WO2022160207A1 - 一种变换电路、变换电路预充电控制方法及光伏系统 - Google Patents

一种变换电路、变换电路预充电控制方法及光伏系统 Download PDF

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Publication number
WO2022160207A1
WO2022160207A1 PCT/CN2021/074236 CN2021074236W WO2022160207A1 WO 2022160207 A1 WO2022160207 A1 WO 2022160207A1 CN 2021074236 W CN2021074236 W CN 2021074236W WO 2022160207 A1 WO2022160207 A1 WO 2022160207A1
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Prior art keywords
unit
switch
input
sub
circuit
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PCT/CN2021/074236
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English (en)
French (fr)
Inventor
许富强
王均
于心宇
辛凯
石磊
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华为数字能源技术有限公司
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Priority to PCT/CN2021/074236 priority Critical patent/WO2022160207A1/zh
Priority to AU2021424908A priority patent/AU2021424908A1/en
Priority to EP21921817.9A priority patent/EP4246790A4/en
Priority to CN202180072802.1A priority patent/CN116472662A/zh
Publication of WO2022160207A1 publication Critical patent/WO2022160207A1/zh
Priority to US18/329,902 priority patent/US20230318434A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H02M1/0058—Transistor switching losses by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0083—Converters characterised by their input or output configuration
    • H02M1/0093—Converters characterised by their input or output configuration wherein the output is created by adding a regulated voltage to or subtracting it from an unregulated input
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0095—Hybrid converter topologies, e.g. NPC mixed with flying capacitor, thyristor converter mixed with MMC or charge pump mixed with buck
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/36—Means for starting or stopping converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/01—Resonant DC/DC converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1582—Buck-boost converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • H02J2300/26—The renewable source being solar energy of photovoltaic origin involving maximum power point tracking control for photovoltaic sources
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/487—Neutral point clamped inverters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Definitions

  • the present application relates to the field of electronic technology, and in particular, to a conversion circuit, a precharge control method for the conversion circuit, and a photovoltaic system.
  • Traditional DC converters generally use magnetic components such as inductors and transformers to transfer energy, so that traditional DC converters work in a hard switching state.
  • the hard switching state has a large switching loss in the DC converter, which reduces the working efficiency of the DC converter.
  • the magnetic components such as inductors and transformers are relatively large, so the power density of traditional DC converters is low.
  • resonant switched capacitor converters In order to improve the performance of DC converters, new DC converters have been proposed, such as resonant switched capacitor converters (RSCCs).
  • the resonant unit In the RSCC, the resonant unit is used to transmit energy, so that the power switching device in the RSCC can work in a soft switching state, thereby improving the working efficiency of the RSCC.
  • the resonant unit generally includes a resonant inductor and a resonant capacitor. Compared with magnetic components such as inductors and transformers in traditional DC converters, the resonant unit has a smaller volume. Therefore, the RSCC has a higher power density.
  • an RSCC can be used for voltage conversion, such as boost conversion, buck conversion, voltage polarity conversion and other application scenarios.
  • an RSCC includes a plurality of switch tubes (switches), a plurality of capacitors, a plurality of diodes and a resonance unit, and the resonance unit usually includes a resonance inductor and a resonance capacitor.
  • Figure 1 shows a topology diagram of an RSCC circuit. After supplying the input voltage to the RSCC, the output target voltage can be achieved by controlling the off-states of multiple switches. Since the RSCC is in the working state of outputting the target voltage, the voltage of the output filter capacitor is almost zero.
  • the current generated by the resonant inductance in the resonant unit has an impact on the power switch tube in the RSCC, which affects the performance of the switch tube, resulting in a decrease in the working performance of the RSCC.
  • the present application provides a conversion circuit, a precharge control method for the conversion circuit, and a photovoltaic system, which are used to avoid additional cost, avoid current generation in the circuit when the RSCC is in a working state and cause an impact on the switch, and ensure the working performance of the RSCC.
  • the present application provides a conversion circuit, including: a first power supply, a resonant switched capacitor converter RSCC, and a control circuit.
  • the RSCC includes a switch unit, an output filter unit, a first input end S1, a second input end S2 and an output end S3, and the switch unit is connected between the first input end S1 and the second input end S2 , the output filtering unit is connected between the second input end S2 and the output end S3.
  • One pole of the first power supply is connected to the first input terminal S1, the other pole of the first power supply is connected to the second input terminal S2, and the first power supply is used to provide input for the RSCC Voltage.
  • the control circuit is connected to the switch unit, and is configured to control the switch unit in the RSCC to transmit the power provided by the first power source to the output filter unit before controlling the RSCC to work.
  • the RSCC in the conversion circuit can be used in a DC-DC conversion scenario, such as a DC-DC conversion circuit, which can perform step-up conversion, step-down conversion, or polarity conversion.
  • the control circuit in the conversion circuit can control the RSCC to work. Before controlling the RSCC to work, the control circuit controls the switch unit in the RSCC to transmit the electric energy provided by the first power source to the output filtering unit, so as to increase the voltage of the output filtering unit. Since the output filter unit has stored energy, its voltage is not zero.
  • the control circuit controls the operation of the RSCC, the current formed in the circuit is weak, and the influence on the switch unit in the RSCC is weak, which can ensure the performance of the switch unit.
  • the control circuit can make the first power supply charge the output filter unit, increase the voltage of the output filter unit, and can ensure the power density of the RSCC without adding an additional charging circuit.
  • the RSCC further includes a resonance unit and a clamping unit.
  • the clamping unit is connected in parallel with the output filtering unit.
  • the switch unit is connected to one end of the resonance unit, and the other end of the resonance unit is connected to the clamping unit.
  • the control circuit controls the switch unit in the RSCC to transmit the power provided by the first power source to the output filtering unit, the control circuit is specifically configured to: control the switch unit to transmit the power provided by the first power source to the output filter unit. the resonance unit; controlling the switch unit to transmit the electric energy in the resonance unit to the output filtering unit.
  • the control circuit can transmit the energy provided by the first power source to the resonance unit by controlling the switch unit, so that the first power source can charge the resonance unit. Then, the control switch unit transmits the power in the resonance unit to the output filter unit, so that the resonance unit can charge the output filter unit. Since the resonance unit and the output filter unit store electric energy, the voltage of the resonance unit is not zero, and the voltage of the output filter unit is not zero, which can reduce the current formed in the circuit when the RSCC works.
  • the control circuit controls the switch unit to transmit the power provided by the first power supply to the resonance unit, the first power supply, the switch unit, the resonance unit, the The clamping unit forms a first path, the switching unit and the second input end S2 are disconnected, and the clamping unit and the output end S3 are disconnected.
  • the control circuit controls the switch unit to transmit the electrical energy in the resonance unit to the output filter unit, the switch unit, the resonance unit, the clamping unit, and the output filter unit form a first Two channels, the clamping unit and the second input end S2 are disconnected.
  • the resonance unit in the RSCC can be used as an energy transfer unit.
  • the control circuit controls the switch unit to transmit the power provided by the first power source to the output filter unit
  • the switch unit can be controlled first, so that the first power source, the switch unit, the resonance unit and the clamping unit form a first path, and the first power source can pass through The first path charges the resonance unit.
  • the control circuit controls the switch unit, so that the switch unit, the resonance unit, the clamp unit and the output filter unit form a second channel, and the resonance unit can charge the output filter unit via the second channel.
  • the RSCC further includes an input filter unit, and the input filter unit is connected in parallel with the switch unit.
  • the input filtering unit is used for storing electric energy provided by the first power source.
  • the input filtering unit includes a first sub-input filtering unit and a second sub-input filtering unit, the first sub-input filtering unit is connected in series with the second sub-input filtering unit, and the first sub-input filtering unit is connected to the second sub-input filtering unit. One end connected to the second sub-input filtering unit is connected to the switch unit.
  • control circuit controls the switch unit to transmit the power provided by the first power source to the resonance unit
  • control circuit is specifically configured to: control the switch unit to provide the first power source to the first sub-input filter The power in the unit is transmitted to the resonance unit; or, the switch unit is controlled to provide the first power to the power in the first sub-input filtering unit and to the second sub-input filtering unit The power is transmitted to the resonant unit.
  • the input filter unit is connected in parallel with the switch unit, and the input filter unit is connected between the two poles of the first power supply.
  • the first power source may provide power to the input filtering unit.
  • the input filtering unit may also store electrical energy provided by the first power source.
  • the input filtering unit in RSCC may include multiple sub-input filtering units.
  • the control circuit may use one or more sub-input filter units in the input filter unit as an energy transfer unit in the process of controlling the switch unit to transmit the electrical energy provided by the first power source to the resonance unit.
  • the control circuit may control the switching unit to transmit the power in the one or more sub-input filtering units to the resonance unit.
  • the control circuit uses one or more sub-input filtering units in the input filtering unit as an energy transfer unit, which can flexibly and finely charge the resonance unit.
  • the control circuit controls the switch unit to transmit the power provided by the first power supply to the first sub-input filtering unit to the resonance unit
  • the first sub-input A third path is formed between the filter unit, the switch unit, the resonance unit, and the clamp unit, the switch unit and the first input end S1 are disconnected, and the switch unit and the second The circuit between the input ends S2 is disconnected, and the clamping unit and the output filtering unit are disconnected.
  • control circuit controls the switch unit to transmit the power provided by the first power source to the first sub-input filtering unit and the power provided to the second sub-input filtering unit to the resonance unit Controlling the switch unit to transmit the power in the first sub-input filtering unit and the power in the second sub-input filtering unit to the resonance unit, the first sub-input filtering unit, the second sub-input filtering unit A fourth path is formed between the filter unit, the switch unit, the resonance unit, and the clamp unit, the switch unit and the second input end S2 are disconnected, and the clamp unit and the output Open circuit between filter units.
  • the control circuit controls the switch unit, so that the first sub-input filter unit, the switch unit, the resonance unit, and the clamp unit form a third path.
  • the first sub-input filtering unit may charge the resonance unit via the third channel.
  • the control circuit controls the switching unit, and a fourth path is formed between the first sub-input filtering unit, the second sub-input filtering unit, the switching unit, the resonance unit, and the clamping unit.
  • the first sub-input filtering unit and the second sub-input filtering unit may charge the resonance unit via the fourth channel.
  • control circuit is further configured to control the switch unit to transmit the power in the first sub-input filtering unit to the output filtering unit.
  • control circuit may control the switch unit, so that the resonance unit may charge the output filter unit.
  • the control circuit can also control the switch unit to make the first sub-input filter unit charge the output filter unit.
  • the control circuit can use the sub-input filtering unit in the input filtering unit as an energy transfer unit. For example, the first sub-input filtering unit charges the output filtering unit, and the control circuit can flexibly and finely charge the output filtering unit to protect the transformation components in a circuit.
  • the control circuit controls the switch unit to transmit the power in the resonance unit to the output filter unit
  • the clamping unit forms a fifth path, the switch unit and the first sub-input filtering unit are disconnected, and the switch unit and the second input end S2 are disconnected.
  • the control circuit uses the resonance unit in the RSCC as an energy transfer unit. After the resonant unit is charged, the control circuit can control the switch unit so that the resonant unit, the switch unit, the output filter unit and the clamp unit form a fifth channel.
  • the resonance unit may charge the output filtering unit via the fifth channel.
  • the control circuit controls the switch unit to transmit the power in the first sub-input filtering unit to the output filtering unit
  • the first sub-input filtering unit, the switch unit, the resonance unit, the clamping unit, and the output filtering unit form a sixth channel
  • the switch unit and the second input end S2 are disconnected, and the switch unit and the first input end
  • the circuit between S1 is disconnected, and the circuit between the clamping unit and the second input end S2 is disconnected.
  • the control circuit uses the resonance unit and the first sub-input filtering unit in the RSCC as the energy transfer unit.
  • the control circuit controls the switch unit so that the first sub-input filter unit, the switch unit, the resonance unit, the clamp unit and the output filter unit form a sixth channel.
  • the first sub-input filtering unit and the resonance unit can charge the output filtering unit.
  • the first power source includes: at least one photovoltaic string and a first DC-DC boost circuit.
  • the positive pole of the at least one photovoltaic string is connected to the positive input terminal of the first DC-DC boost circuit, and the negative pole of the at least one photovoltaic string is connected to the negative pole of the first DC-DC boost circuit input connection.
  • the positive output terminal of the first DC-DC boost circuit is connected to the first input terminal S1, and the negative output terminal of the first DC-DC boost circuit is connected to the second input terminal S2.
  • the first DC-DC boost circuit is used for converting the voltage provided by the at least one photovoltaic string into the input voltage.
  • the conversion circuit may be applied to a photovoltaic power generation scenario.
  • the first power source may include a photovoltaic string and a first DC-DC boost circuit.
  • the control circuit controls the switch unit in the RSCC to transmit the power provided by the first power source to the output filter unit before controlling the work of the RSCC, which can ensure the work performance of the switch unit in the RSCC, thereby ensuring the work performance of the conversion circuit in the photovoltaic power generation scene.
  • the present application provides a photovoltaic system, comprising at least one conversion circuit as in the first aspect, a plurality of photovoltaic strings, at least one second DC-DC boost circuit, and a DC-AC inverter circuit.
  • the positive output terminal of each second DC-DC boost circuit is connected to the positive input terminal of the DC-AC inverter circuit, and the negative output terminal of each second DC-DC boost circuit is respectively connected to one of the
  • the second input terminal S2 of the RSCC in the conversion circuit is connected to the zero-level terminal of the DC-AC inverter circuit; wherein, the negative output terminal of each second DC-DC boost circuit is connected to a different output terminal in the conversion circuit.
  • the second input terminal S2 of RSCC is connected to the zero-level terminal of the DC-AC inverter circuit.
  • the output end S3 of the RSCC in each of the conversion circuits is connected to the negative input end of the DC-AC inverter circuit.
  • the positive input terminal of each second DC-DC boost circuit is connected to the positive terminal of at least one photovoltaic string, and the negative input terminal of each second DC-DC boost circuit is connected to the at least one photovoltaic string. negative electrode.
  • Each of the second DC-DC boost circuits is used for boosting the voltage provided by the connected photovoltaic strings to obtain a first input voltage, and providing the first input to the DC-AC inverter circuit Voltage.
  • a second input voltage is provided to the DC-AC inverter circuit.
  • the output end of the DC-AC inverter circuit is used for connecting with a power grid, so as to convert the first input voltage and the second input voltage into AC voltage and then provide them to the power grid.
  • the photovoltaic system includes any one of the conversion circuits in the first aspect, and the RSCC in the conversion circuit can provide a second input voltage for the DC-AC inverter circuit in the photovoltaic system when working.
  • the control circuit in the conversion circuit can control the switch unit in the RSCC to transmit the electric energy provided by the first power supply to the output filter unit in the RSCC before controlling the operation of the RSCC, so as to avoid the current generated in the circuit to the switch when the RSCC is in the working state.
  • the impact of the unit ensures the working performance of the switch unit, thereby ensuring the working performance of the RSCC and the working performance of the photovoltaic system. And there is no need to increase the cost of additional charging circuits and control switches.
  • an embodiment of the present application provides a conversion circuit precharge control method, which is applied to a conversion circuit, where the conversion circuit includes a first power supply, a resonant switched capacitor converter RSCC, and the RSCC includes a switching unit and an output filtering unit.
  • the method may be performed by a control circuit or a controller, and the method includes: the control circuit controls the switch unit to transmit the power provided by the first power source to the output filter unit.
  • the control circuit controls the RSCC to work if it is determined that the output filtering unit voltage is greater than a preset threshold.
  • the control circuit controls the switch unit in the RSCC to transmit the power provided by the first power source to the output filter unit, so as to increase the voltage of the output filter unit. Since the output filter unit stores electrical energy, its voltage is not zero.
  • the control circuit controls the operation of the RSCC, the current formed in the circuit is weak, and the influence on the switch unit in the RSCC is weak, which can ensure the performance of the switch unit.
  • the control circuit can make the first power supply charge the output filter unit, increase the voltage of the output filter unit, and can ensure the power density of the RSCC without adding an additional charging circuit.
  • the RSCC further includes a resonance unit;
  • the controlling the switching unit to transmit the power provided by the first power source to the output filtering unit includes: a control circuit controlling the switching unit to The power provided by the first power source is transmitted to the resonance unit.
  • the control circuit controls the switch unit to transmit the power in the resonance unit to the output filter unit.
  • the control circuit can transmit the energy provided by the first power source to the resonance unit by controlling the switch unit, so that the first power source can charge the resonance unit. Then, the control switch unit transmits the power in the resonance unit to the output filter unit, so that the resonance unit can charge the output filter unit. Since the resonance unit and the output filter unit store electric energy, the voltage of the resonance unit is not zero, and the voltage of the output filter unit is not zero, which can reduce the current formed in the circuit when the RSCC works.
  • the RSCC further includes an input filtering unit, and the input filtering unit includes a first sub-input filtering unit and a second sub-input filtering unit; the method further includes: the control circuit controls the switch unit to The electrical energy in the first sub-input filtering unit is transmitted to the output filtering unit.
  • control circuit may also control the switch unit to make the first sub-input filtering unit charge the output filtering unit.
  • the control circuit can use the sub-input filtering unit in the input filtering unit as an energy transfer unit.
  • the first sub-input filtering unit charges the output filtering unit, and the control circuit can flexibly and finely charge the output filtering unit to protect the transformation components in a circuit.
  • the controlling the switch unit to transmit the power provided by the first power source to the resonance unit includes: a control circuit controlling the switch unit to provide the first power source to the first power source.
  • the power in a sub-input filtering unit is transmitted to the resonance unit; or, the control circuit controls the switching unit to provide the first power to the power in the first sub-input filtering unit and to the first sub-input filtering unit.
  • the electrical energy in the two sub-input filtering units is transmitted to the resonance unit.
  • the control circuit may use one or more sub-input filter units in the input filter unit as an energy transfer unit during the process of controlling the switch unit to transmit the power provided by the first power source to the resonance unit.
  • the control circuit may control the switching unit to transmit the power in the one or more sub-input filtering units to the resonance unit. For example, by transferring the energy in the first sub-input filtering unit to the resonance unit, the impact on the switch unit caused by the current generated during the charging of the resonance unit can be reduced.
  • the control circuit uses one or more sub-input filtering units in the input filtering unit as an energy transfer unit, which can flexibly and finely charge the resonance unit.
  • an embodiment of the present application provides a conversion circuit precharge control method, which is applied to a control circuit or a controller.
  • the method may include the following steps: controlling the switch unit to transmit the power in the first sub-input filtering unit to the resonance unit until the resonance unit voltage is greater than a first preset threshold.
  • operation 1 and operation 2 are performed.
  • operation 1 is to control the switch unit to transmit the power in the first sub-input filter unit and the power in the second sub-input filter unit to the resonance unit
  • operation 2 is to control the switch unit to transfer the power in the resonance unit to the first sub-filter unit.
  • the power in the input filter unit is transmitted to the output filter unit.
  • operation 3 and operation 4 are performed, wherein operation 3 is to control the switch unit to transmit the electric energy in the first sub-input filtering unit to the resonance unit, and operation 3 is to control the switch unit to transmit the electric energy in the resonance unit transmitted to the output filter unit.
  • the controller may control the switch unit to transmit the electrical energy in the first sub-input filtering unit to the resonance unit in each control cycle, until the voltage of the resonance unit is greater than the first preset threshold, so that the voltage of the resonance unit can be adjusted gradually increases and is greater than the first preset threshold. Then, the first sub-input filtering unit and the resonance unit are used as the energy transfer unit, and the controller can transmit the electric energy provided by the first power source to the output filtering unit by performing operation 1 and operation 2 according to the first preset manner, and In this process, the current generated by the circuit is relatively weak, which ensures the working performance of the switching unit. After the controller performs operation 2, the output filter unit voltage is not zero. By performing operation 3 and operation 4 according to the second preset manner, the controller can also realize that the power provided by the first power source is transmitted to the output filtering unit, and the output filtering unit is provided with more power.
  • the controller may further control the switch unit to transmit the power in the resonance unit and the power in the first sub-input filtering unit to In the output filtering unit, until the voltage of the resonance unit is less than or equal to the sum of the voltage of the output filtering unit and the voltage of the first sub-input filtering unit.
  • the controller controls the switch unit according to the second preset mode, so that the resonance unit and the first sub-input filtering unit charge the output filtering unit, so that the voltage of the resonance unit is less than or equal to the sum of the voltage of the output filter unit and the voltage of the first sub-input filter unit, which can reduce the current spike generated in the subsequent charging process of the controller and affect the working performance of the switch unit.
  • the controller may perform operation 5 according to the third preset method. and operation 6 until the output filter unit voltage is greater than the input voltage provided by the first power supply, wherein operation 5 is to control the switch unit to transmit the power in the first sub-input filter unit and the power in the second sub-input filter unit to the resonance unit Among them, operation 6 is to control the switch unit to transmit the power in the resonance unit to the output filter unit.
  • the controller may perform operations 5 and 6 according to the third preset manner, so that the voltage of the output filtering unit is the input voltage.
  • the controller can control the RSCC to work.
  • the controller may control the switch unit to convert the electric energy in the resonance unit. It is transmitted to the output filtering unit until the voltage of the resonance unit is equal to the first preset threshold. Or control the switch unit to transmit the electric energy in the first sub-input filter unit to the output filter unit until the voltage of the resonance unit is equal to the first preset threshold.
  • an embodiment of the present application provides a computer-readable storage medium, where the computer-readable storage medium includes a computer program, and when the computer program runs on a processor, the processor causes the processor to execute the third embodiment of the present application.
  • an embodiment of the present application provides a computer program product that, when the computer program product runs on an electronic device, enables the electronic device to execute the third aspect and any possible design of the third aspect of the embodiment of the present application.
  • 1 is a schematic structural diagram of a conversion circuit comprising RSCC
  • FIG. 2 is a schematic structural diagram of a conversion circuit capable of realizing precharging of RSCC
  • FIG. 3 is a schematic structural diagram of a conversion circuit
  • FIG. 4 is a schematic diagram of a path in a conversion circuit in a charging process
  • FIG. 5 is a schematic diagram of a path in a conversion circuit in a charging process
  • FIG. 6 is a schematic structural diagram of a conversion circuit
  • FIG. 8 is a schematic diagram of a path in a conversion circuit in a charging process
  • FIG. 9 is a schematic diagram of a path in a conversion circuit in a charging process
  • FIG. 10 is a schematic diagram of a path in a conversion circuit in a charging process
  • FIG. 11 is a schematic diagram of a path in a conversion circuit in a charging process
  • FIG. 12 is a schematic diagram of a path in a conversion circuit in a charging process
  • FIG. 13 is a schematic structural diagram of a conversion circuit
  • 15 is a schematic flowchart of a method for precharging a conversion circuit
  • 16 is a schematic diagram of a path in a conversion circuit in a charging process
  • 17 is a schematic diagram of a path in a conversion circuit in a charging process
  • FIG. 18 is a schematic diagram of a path in a conversion circuit in a charging process
  • 19 is a schematic diagram of a path in a conversion circuit in a charging process
  • 20 is a schematic structural diagram of a power supply
  • 21 is a schematic structural diagram of a photovoltaic system
  • FIG. 22 is a schematic structural diagram of a photovoltaic system.
  • RSCC Magnetic components such as inductors and transformers in traditional DC converters are bulky, which makes the power density of traditional DC converters low.
  • RSCC is a new type of DC converter.
  • the resonant unit using resonant inductance and resonant capacitor transmits energy.
  • the volume of the resonant unit is small, so the RSCC has a high power density.
  • the resonant unit can also make the power switching device in the RSCC work in a soft switching state, improve the working efficiency of the RSCC, and also improve the performance of the system using the RSCC.
  • an RSCC can be used in DC-DC conversion circuits, and can perform voltage conversion on DC voltage, such as boost conversion, step-down conversion, voltage polarity conversion, etc., and output the converted DC voltage.
  • an RSCC includes a plurality of switch tubes (switches), a plurality of capacitors, a plurality of diodes and a resonance unit. After providing the input voltage to the RSCC, the output target voltage is achieved by controlling the off-states of multiple switches.
  • FIG. 1 A transform circuit topology including RSCC is shown in FIG. 1 .
  • the conversion circuit includes a power supply (the input voltage is Vin) and RSCC.
  • the RSCC includes three connection terminals, which are the first input terminal 1 and the second input terminal 2 respectively. One end of the power supply is connected to the first input terminal 1, and the other end of the power supply is connected to the second input terminal 2 (in Figure 1, the positive pole of the power supply is connected to the first input terminal 1, and the negative pole of the power supply is connected to the second input terminal 2 as an example. ).
  • RSCC includes a first branch formed by series connected filter capacitor C1, filter capacitor C2 and output filter capacitor C3, a second branch formed by series connected switch T1, switch T2, switch T3 and switch T4, diode D3 and diode D4 branch, diode D1, diode D2 and resonant unit.
  • the resonance unit includes a resonance capacitance Cr and a resonance inductance Lr connected in series.
  • one end of the filter capacitor C1 is connected to the first input terminal 1, and the other end is connected to the filter capacitor C2.
  • One end of the output filter capacitor C3 is connected to the filter capacitor C2, and the other end is connected to the output terminal 3.
  • one end of the switch T1 is connected to the first input terminal 1, and the other end is connected to the switch T2.
  • One end of the switch T4 is connected to the switch T3, and the other end is connected to the cathode of the diode D3.
  • the anode of the diode D3 is connected to the cathode of the diode D4 , and the anode of the diode D4 is connected to the output terminal 3 .
  • the control terminals of the switch T1, the switch T2, the switch T3 and the switch T4 in the RSCC can be connected to the control circuit.
  • the control circuit can send a driving signal or a pulse signal to the switch to control the switch to be in an on state or in an off state.
  • the control circuit can also send the drive signal corresponding to the control sequence to each switch according to the preset control sequence and the drive signal of each switch corresponding to each control sequence, so that the RSCC is in a working state and realizes the input
  • the voltage is converted to the target output voltage.
  • the voltage of the output filter capacitor C3 is almost zero, and the voltage of the resonant capacitor Cr is also almost zero.
  • the current generated by the resonant inductor Lr will have an impact on power components such as switches, affecting the performance of the switching components, resulting in a decrease in the working performance of the RSCC.
  • the power components such as the output filter capacitor and the resonant capacitor in the RSCC can be charged before the control circuit controls the RSCC to be in the working state.
  • the current generated by the resonant inductor Lr is reduced, thereby reducing the impact of the current on each switch.
  • the charging circuit and the switch control unit are connected to the RSCC.
  • the charging circuit can charge the output filter capacitor C3, and can also charge the resonant capacitor Cr.
  • the switch control unit can control the charging circuit to charge the output filter capacitor C3 and the resonant capacitor Cr respectively, so that the voltages of the output filter capacitor C3 and the resonant capacitor Cr are not zero before the RSCC is in the working state.
  • Adding a charging circuit and a switch-controlled power supply can avoid the impact of the current formed by the resonant inductor Lr on each switch when the RSCC is in a working state.
  • this charging method increases the cost of the conversion circuit, and also increases the area of the conversion circuit, resulting in a decrease in the power density of the conversion circuit.
  • an embodiment of the present application provides a method for charging an output filter capacitor in an RSCC, which can be applied to a conversion circuit including an RSCC, so as not to increase additional costs, and to avoid generating a current pair in the circuit when the RSCC is in a working state
  • the switch causes an impact to ensure the working performance of the RSCC.
  • the conversion circuit provided in this embodiment of the present application may include an RSCC 31 , a first power supply 32 and a control circuit 33 .
  • the RSCC 31 may include a switching unit 301, an output filtering unit 304, a first input S1, a second input S2 and an output S3.
  • the switch unit 301 may be connected between the first input terminal S1 and the second input terminal S2.
  • the control circuit 33 is connected to the switch unit 301 and can control the switch unit 301 .
  • the output filtering unit 304 may be connected between the second input terminal S2 and the output terminal S3.
  • the output filter unit 304 may include at least one capacitor, such as an output filter capacitor.
  • Two poles of the first power supply 32 are respectively connected to the first input end S1 and the second input end S2 of the RSCC 31 .
  • the positive pole of the first power supply 32 is connected to the first input terminal S1
  • the negative pole of the first power supply 32 is connected to the second input terminal S2.
  • the first power source 32 can provide power for the RSCC 31 .
  • the control circuit 33 can be used for the output filtering charging method in the RSCC provided in this application.
  • the control circuit 33 may control the switch unit 301 to transmit the power provided by the first power source to the output filter unit 304 before controlling the RSCC to work.
  • the control circuit 33 controls the RSCC 31 to work, which may refer to controlling the RSCC 31 to be in a working state.
  • the RSCC 31 is controlled to convert the input voltage provided by the first power supply 32 into a target voltage, or a target output voltage.
  • the target voltage can be supplied to a load, for example, an inverter circuit and the like, via the second input terminal S2 and the output terminal S3 of the RSCC 31 .
  • RSCC 31 can be used in boost conversion, buck conversion, polarity conversion and other scenarios.
  • a boost conversion scenario the value of the target voltage can be greater than the input voltage.
  • a buck conversion scenario the value of the target voltage can be smaller than the input voltage.
  • the target voltage can be equal to the absolute value of the input voltage, and the polarity is opposite.
  • RSCC31 can also be applied to other voltage conversion scenarios, which will not be listed here.
  • the control circuit 33 may be implemented as a controller.
  • the control circuit 33 may also include a plurality of control units, and different control units may be used to control the RSCC to be in different operating states.
  • the first control unit is used to control the RSCC 31 to be in a working state
  • the second control unit is used to control the switch unit 301 to transmit the power provided by the first power supply 32 to the output filtering unit 304 before the RSCC 31 is working.
  • the process in which the control circuit 33 controls the switching unit 301 to transmit the power provided by the first power supply 32 to the output filtering unit 304 before the RSCC 31 works can be regarded as controlling the RSCC 31 to be in a precharged state.
  • the control circuit 33 can control the switch unit 301 to transmit the power provided by the first power source 32 to the output filter unit 304, so that the first power source 32 can charge the output filter unit 304 in the RSCC 31.
  • the control circuit 33 may send (or provide) a control signal or a driving signal to the control switch unit 301 .
  • the switch unit 301 can transmit the power provided by the first power supply 32 to the output filter unit 304 when receiving the control signal or the driving signal.
  • the switching unit 301 may also not transmit the power provided by the first power supply 32 to the output filtering unit 304 when no control signal or driving signal is received.
  • the control circuit 33 continues to send a control signal or a driving signal to the switch unit 301 within a preset time period.
  • the switching unit 301 continuously transmits the power provided by the first power supply 32 to the output filtering unit 304 within a preset time period.
  • the preset duration may be less than one control period.
  • the duration of the charging of the output filter unit 304 is different, and the voltage increase of the output filter unit 304 is also different.
  • the duration of the control circuit 33 sending the control signal or the driving signal to the switch unit 301 is different, and the situation of increasing the voltage across the output filtering unit is also different.
  • the control circuit may continue to send the control signal or the driving signal to the switch unit 301 within the first time period.
  • the control circuit may also continuously send a control signal or a driving signal to the switch unit 301 within the second time period. If the first duration and the second duration are different values, the voltage increase after the output filter unit 304 is charged for the first duration is different from the voltage increase after the output filter unit 304 is charged for the second duration.
  • the control circuit 33 may control the switch unit 301 to transmit the power of the first power supply 32 to the output filter unit 304 multiple times, so that the output filter unit 304 may be charged multiple times.
  • the duration of each time the control circuit 33 controls the switch unit 301 to transmit the power of the first power source 32 to the output filter unit 304 may be the same or different.
  • the control circuit 33 can continuously send the control signal or the driving signal to the switch unit 301 in the same period or in different periods in each control cycle, so that the switch unit 301 transmits the power of the first power source 32 to the output filter unit 304.
  • the embodiments of the present application provide a method for charging the output filter capacitor in the RSCC, which can ensure the performance of the power components in the conversion circuit and the power density of the conversion circuit, and does not need to increase the cost of the conversion circuit.
  • the RSCC 31 may also include a resonance unit 302 and a clamping unit 303.
  • the clamping unit 303 is connected in parallel with the output filtering unit 304.
  • the clamping unit 303 can be used to restrict the voltage of the second input terminal S2 from changing.
  • the switch unit 301 is connected to one end of the resonance unit 302 , and the other end of the resonance unit 302 is connected to the clamping unit 303 .
  • the resonant unit 302 may include a resonant capacitor and a resonant inductor connected in series. The resonant unit 302 can be used for transferring energy, so that the switching device in the switching unit 301 works in a soft switching state.
  • An input filtering unit 305 may also be included in the RSCC 31.
  • the input filtering unit 305 is connected in parallel with the switching unit 301, and can be used to stabilize the input voltage provided by the first power supply 32 when the RSCC 31 is in a working state.
  • the input filtering unit 305 may include at least one capacitor connected in series.
  • the input filter unit 305 is connected between the two poles of the first power supply 32 .
  • the first power supply 32 can directly provide power to the input filter unit 305 , and the input filter unit 305 can also be used to store the power provided by the first power supply 32 .
  • the first end 301a of the switch unit 301 is connected to the first input end S1 of the RSCC 31 and the input end 305a of the input filtering unit 305, respectively.
  • the second terminal 301b of the switch unit 301 is connected to the second input terminal S2.
  • the third end 301c of the switch unit 301 is connected to the first end 302a of the resonance unit 302 .
  • the fourth terminal 301 d of the switch unit 301 may be connected to the control circuit 33 .
  • the second end 302b of the resonance unit 302 is connected to the first input end 303a of the clamping unit 303 .
  • the second input end 303b of the clamping unit 303 is connected to the output end S3 of the RSCC 31 .
  • the output terminal 303c of the clamping unit 303 is connected to the second input terminal S2 of the RSCC 31 .
  • the input terminal 305a of the input filtering unit 305 is connected to the first input terminal S1 and the first terminal 301a of the switching unit 301, respectively.
  • the output terminal 305b of the input filtering unit 305 is connected to the second input terminal S2 and the input terminal 304a of the output filtering unit 304, respectively.
  • the input terminal 304a of the output filtering unit 304 is connected to the output terminal 305b and the second input terminal S2 of the input filtering unit 305, respectively.
  • the output terminal 304b of the output filtering unit 304 is connected to the output terminal S3 of the RSCC 31.
  • the resonance unit 302 may also be used to transfer electrical energy, or the resonance unit 302 may be used as an energy transfer unit (an energy relay unit, an energy relay component, or an energy relay module).
  • the control circuit 33 controls the switch unit 301 in the RSCC 31 to transmit the power provided by the first power source 32 to the output filtering unit 304
  • the switch unit 301 can be controlled to transmit the power provided by the first power source 32 to the output filter unit 304.
  • the resonance unit 302 can realize that the first power supply 32 charges the resonance unit 302 .
  • the switch unit 301 is controlled to transmit the power in the resonance unit 302 to the output filter unit 304 , so that the resonance unit 302 can charge the output filter unit 304 .
  • the resonance unit 302 can be used as an energy transfer medium to receive charging from the first power source 32 .
  • the resonant unit 302 can also provide power to the output filtering unit 304 after being charged, and charge the output filtering unit 304 .
  • the control circuit 33 controls the switching unit 301 to charge the output filtering unit 304 and the resonance unit 302 in the RSCC 31, which can ensure the performance of the switching elements in the conversion circuit, and the performance of the conversion circuit. power density, and using the components in the conversion circuit to charge the resonant capacitor and output filter capacitor in the RSCC without adding extra cost.
  • the switch unit 301 may include a plurality of switches connected in series.
  • the control circuit 33 controls the switch unit 301 to transmit the power provided by the first power source 32 to the resonance unit 302 , the control circuit 33 can control the on-off state of each switch in the switch unit 301 to make the first power source 32
  • the switch unit 301, the resonance unit 302, and the clamp unit 303 form a first path, the switch unit 301 and the second input end S2 are disconnected, and the second input end 303b of the clamp unit 303 and the output end S3 are disconnected.
  • the first end 302a of the resonance unit 302 is connected to one pole of the first power supply 32 via the switch unit 301, and the second end 302b of the resonance unit 302 is connected to the other pole of the first power supply 32 via the clamping unit 303, and the first power supply 32
  • the resonance unit 302 may be charged.
  • FIG. 4 shows the path and disconnection conditions in the RSCC 31 during the charging process of the first power supply 32 to the resonant unit 302, wherein the thick line shows the first path in the RSCC 31, and the dashed line shows the case where the RSCC 31 is disconnected.
  • the control circuit 33 may control the switch unit 301 for multiple times to transmit the power provided by the first power source 32 to the resonance unit 302, so that the resonance unit 302 is charged multiple times. After the resonance unit 302 charges the output filter unit 304, the voltage decreases. In order to further reduce the current generated by the inductance in the resonance unit 302 when the RSCC 31 is in the working state.
  • the control circuit 33 can control the switch unit 301 again to transmit the power provided by the first power source 32 to the resonance unit 302 , so that the first power source 32 charges the resonance unit 302 again.
  • the time period for which the resonant power supply 302 is charged each time may be the same or different.
  • the control circuit 33 can control the charging duration of the resonance unit 302 to be the preset duration by controlling the switch unit 301 to continuously transmit the power provided by the first power source 32 to the resonance unit 302 within a preset duration.
  • the preset duration may be less than the duration corresponding to one control period.
  • the duration corresponding to one control period may be 55 microseconds
  • the preset duration may be 1.8%*55 microseconds
  • the preset duration may also be 2%*55 microseconds.
  • the control circuit 33 controls the switch unit 301 to transmit the power in the resonance unit 302 to the output filter unit 304
  • the control circuit 33 can control the on-off state of each switch in the switch unit 301, so that the switch unit 301, the resonance unit 302, the clamp The unit 303 and the output filtering unit 304 form a second path, the second end 301b of the switch unit 301 is connected to the second input end S2, and the output end 303c of the clamping unit 303 is disconnected from the second input end S2.
  • the resonance unit 302 stores the electric energy provided by the first power supply 32. Since the voltage of the output filter unit 304 is almost zero, after the second path is formed, the resonance unit 302 discharges, so that the resonance unit 302 charges the output filter unit 304. Fig.
  • FIG. 5 shows the path and disconnection in the RSCC 31 during the charging process of the resonant unit 302 to the output filter unit 304, wherein the thick line shows the second path in the RSCC 31, and the dashed line shows the disconnection of the RSCC 31.
  • the output filtering unit 304 can also be charged multiple times.
  • the control circuit 33 can control the switch unit 301 to transmit the power in the resonance unit 302 to the output filter unit 304 for many times.
  • the control circuit 33 may control the switching unit 301 to transmit the power in the resonance unit 302 to the output filtering unit 304 after the resonance unit 302 is recharged. Each time the output filtering unit 304 is charged may be the same or different.
  • control circuit 33 may determine whether the voltage of the resonance unit 302 is within the first voltage range after the resonance unit 302 charges the output filtering unit 304 . If the voltage of the resonance unit 302 is less than the minimum value in the first voltage range, the control circuit 33 may control the switch unit 301 to transmit the power provided by the first power source 32 to the resonance unit 302 .
  • the first voltage range may also be determined according to the voltage provided by the first power supply 32 .
  • the value in the first voltage range can be any value close to 0.5Vin, which is half the voltage value of the output voltage Vin of the first power supply 32 .
  • the minimum value in the first voltage range may be 0.48Vin, and the first voltage range may be [0.48Vin, Vin].
  • the first voltage range may also consist of discrete values, such as ⁇ 0.48Vin, 0.485Vin, 0.5Vin, 0.51Vin ⁇ .
  • a value range of 0.5Vin, which is close to the half voltage value of the output voltage Vin of the first power supply 32 can be configured according to the component parameters in the RSCC.
  • control circuit 33 may also determine whether the voltage of the output filtering unit 304 is greater than or equal to a preset voltage value after the resonance unit 302 charges the output filtering unit 304 . If the voltage across the output filtering unit 303 is greater than or equal to the preset voltage value, the control circuit 33 may determine that the charging of the output filtering unit 304 in the RSCC 31 is completed.
  • the preset voltage value may be the input voltage Vin.
  • the control circuit 33 can also control the RSCC 31 to be in a working state and output the target voltage after determining that the output filtering unit 304 is charged.
  • the control circuit 33 may also determine whether the voltage of the resonance unit 302 is within the first voltage range after determining that the charging of the output filtering unit 304 is completed. If the voltage of the resonance unit 302 is less than the minimum value within the first voltage range, the control circuit 33 may control the switch unit 301 one or more times to transmit the power provided by the first power supply 32 to the resonance unit 302, so that the voltage of the resonance unit 302 is greater than or equal to Minimum value in the first voltage range.
  • the control circuit 33 determines that the voltage of the output filtering unit 304 is greater than or equal to the preset voltage value, and that the voltage of the resonance unit 302 is greater than or equal to the minimum value within the first voltage range, and the charging of the output filtering unit 304 and the resonance unit 302 can be determined to be completed. Then control the RSCC 31 to be in a working state and output the target voltage.
  • the switch unit 301 may include at least two switches, two of the at least two switches are connected in series, and a connection line between the two switches is provided with a first node, the first node It can be used as the third terminal 301c of the switch unit 301 .
  • the switches in the embodiments of the present application may be power switch tubes, such as field effect transistors.
  • the switches are field effect transistors with parasitic diodes as an example, and are not limited to the specific forms of the switches in the embodiments of the present application.
  • the switch unit 301 may include two switches connected in series. As shown in FIG. 6, the switch unit 301 includes a switch T5 and a switch T6. The end of the switch T5 that is not connected to the switch T6 may serve as the first end 301 a of the switch unit 301 . The end of the switch T6 that is not connected to the switch T5 can be used as the second end 301b of the switch unit 301 .
  • the first node M1 in the switch unit is disposed on the connection line between the switch T6 and the switch T5 , and can be used as the third end 301c of the switch unit 301 , and the first node M1 is connected to the first end 302a of the resonance unit 302 .
  • the clamping unit 303 may include two diodes connected in series, and a second node M2 is provided on the connection line between the two diodes as the first input end 303 a of the clamping unit 303 .
  • the second nodes M2 are respectively connected to the anode of one diode and the cathode of the other diode.
  • the diode whose cathode is connected to the second node M2 can be the first diode
  • the anode of the first diode can be used as the second input terminal 303b of the clamping unit 303 and is connected to the output terminal S3 of the RSCC 31.
  • the other diode is a second diode, the anode of the second diode is connected to the second node M2, and the cathode of the second diode can be used as the output end 303c of the clamping unit 303 and the second input end S2 of the RSCC 31. connect.
  • the clamping unit 303 includes a diode D5 and a diode D6 connected in series, the anode of the diode D5 is connected to the cathode of the diode D6, the cathode of the diode D5 is the output end 303c of the clamping unit 303, and the anode of the diode D5 can be used as the output terminal 303c of the clamping unit 303.
  • the first input terminal 303 a of the clamping unit 303 is the second output terminal 303b of the clamping unit 303 .
  • the resonance unit 302 is connected between the first node M1 and the second node M2. Since the diode has the characteristic of forward conduction, when the current output by the resonance unit 302 flows through the second node M2, the cathode of the diode D6 is connected to the second node M2, the current cannot flow into the diode D6, and the diode D6 is in an off state, which can make the clamping unit
  • the circuit is disconnected between the second input terminal 303b of 303 and the output terminal S3 of RSCC 31 .
  • the clamping unit 303 may also include a diode and a switch, and the diode and the switch are connected in series.
  • the second node M2 is disposed on the connection line between the diode and the switch, and serves as the first input terminal 303 a of the clamping unit 303 .
  • the end of the switch that is not connected to the second node M2 can be used as the second input end 303 b of the clamping unit 303 .
  • the cathode of the diode can be used as the output terminal 303c of the clamping unit 303 .
  • the control circuit 33 can control the on-off state of the switch.
  • the control circuit 33 can control the switch in the clamping unit 303 to be in an off state, and can open the circuit between the second input end 303b of the clamping unit 303 and the output end S3 of the RSCC 31 .
  • the control circuit 33 can also control the switch in the clamping unit 303 to be in a conducting state, so that the second input end 303b of the clamping unit 303 and the output end S3 of the RSCC 31 can be turned on.
  • clamping unit 303 may also be composed of other elements, so as to be able to implement the role or function of the clamping unit 303 in the RSCC 31 in the embodiment of the present application. This embodiment of the present invention does not limit this too much.
  • the resonant inductor and the resonant capacitor in the resonant unit 302 may be connected in series.
  • the resonance unit 302 may include a capacitor C6 and an inductor L1 connected in series, one end of the capacitor C6 not connected to the inductor L1 may be used as the first end 302a of the resonance unit 302, and one end of the inductor L1 not connected to the capacitor C6 may be used as a resonance Second end 302b of cell 302 .
  • the second end 302b of the resonance unit 302 may be connected to the second node M2 between the diode D5 and the diode D6.
  • the first end 302a of the resonance unit 302 may be connected to the first node M1 between the switch T5 and the switch T6.
  • the input filtering unit 305 may include a capacitor C4.
  • the output filtering unit 304 may include a capacitor C5.
  • the control circuit 33 may be connected to each of the at least two switches in the switch unit 301, and the control circuit 33 may control the on-off state of each switch.
  • the control circuit 33 can make the first power supply 32, the switch unit 301, the resonance unit 302, and the clamp unit 303 form a first path by controlling the on-off states of at least two switches of the switch unit 301, and the switch unit 301 and the second input
  • the circuit between the terminals S2 is disconnected, and the circuit between the clamping unit 303 and the output end S3 of the RSCC 31 is disconnected, so as to control the first power supply 32 to charge the resonance unit 302 and the input filtering unit 305 .
  • the switch unit 301 may include two switches, switch T5 and switch T6.
  • the control circuit 33 is connected to the switch T5 and the switch T6, respectively.
  • the control circuit 33 can control the switch T5 in the switch unit 301 to be turned on and the switch T6 to be turned off, and one pole of the first power supply 32 is connected to the resonance unit 302 through the switch T5 in the switch unit 301 .
  • the voltages of the resonant capacitor C6 in the resonant unit 302 are different, so that the induced current generated by the resonant inductor L1 is input into the clamping unit 303 , and then flows into the other pole of the first power supply 32 through the diode D5 in the clamping unit 303 .
  • the second end 302b of the resonance unit 302 is conducted through the diode D5 in the clamping unit 303 and the other pole of the first power supply, so that the first power supply 32, the switching unit 301, the resonance unit 302, and the clamping unit 303 are formed first path.
  • the power provided by the first power source 32 is transmitted to the resonance unit 302 through the switch T5 in the switch unit 301 , so that the first unit 32 can charge the resonance capacitor C6 in the resonance unit 302 .
  • Two poles of the first power supply 32 are respectively connected to two ends of the capacitor C4 in the input filtering unit 305 , and the capacitor C4 can store the electric energy provided by the first power supply 32 .
  • control circuit 33 may also control the switch T5 to be turned off and the switch T6 to be turned on, and the capacitor C6 in the resonance unit 302 is connected to the input end 305a of the input filtering unit 305 via the switch T6 in the switch unit 301 .
  • the output end 304b of the output filtering unit 304 is connected to the inductor L1 in the resonance unit 302 via the diode D6 in the clamping unit 303, so that a second connection is formed between the resonance unit 302, the switching unit 301, the output filtering unit 304 and the clamping unit 303. path.
  • the electrical energy in the resonant capacitor C6 in the resonant unit 302 can be transmitted to the output filter unit 304 via the switch T6 in the switch unit 301 , so that the resonant unit 302 can charge the output filter unit 304 .
  • the control circuit 33 may transmit the energy of the resonance unit 302 as an intermediate medium for multiple times.
  • the control circuit 33 can control the switch unit 301 to transmit the power provided by the first power supply 32 to the output filter unit 305 by controlling the on-off states of the switch T5 and the switch T6 in the switch unit 301 in multiple control cycles.
  • control circuit 33 can cause the switch unit 301 to transmit the power provided by the first power supply 32 to the output filter unit 305 according to the preset control operations in each control cycle.
  • the control circuit 33 may perform a control operation of continuously sending a control signal or a driving signal to the switch T5.
  • the control circuit 33 may provide the switch T5 with a pulse signal whose pulse width is a preset duration in the first control period. After the switch T5 receives the pulse signal, it is in a conducting state until the pulse ends. The switch T6 is in an open-circuit state when no pulse signal is received.
  • the duration of the first control period may be 55 microseconds, the preset duration may be 1.8%*55 microseconds, and the preset duration may also be 2%*55 microseconds.
  • the control circuit 33 may perform the control operation of continuously sending the control signal or the driving signal to the switch T5 in the first half cycle of the first control cycle.
  • the control circuit 33 may also perform the control operation of continuously sending the control signal or the driving signal to the switch T5 in the second half of the first control period.
  • the switch T5 is in an on state
  • the switch T6 is in an off state
  • the power provided by the first power supply 32 is transmitted to the resonance unit 302 through the switch T5.
  • the control circuit 33 may perform a control operation of continuously sending a control signal or a driving signal to the switch T6.
  • the control circuit 33 may provide the switch T6 with a pulse signal whose pulse width is a preset duration in the second control period. After the switch T6 receives the pulse signal, it is in a conducting state until the pulse ends. The switch T5 is in an open state when no pulse signal is received.
  • the duration of the second control period may be 55 microseconds, the preset duration may be 1.8%*55 microseconds, and the preset duration may also be 2%*55 microseconds.
  • the control circuit 33 may perform the control operation of continuously sending the control signal or the driving signal to the switch T6 in the first half cycle of the second control cycle.
  • the control circuit 33 may also perform the control operation of continuously sending the control signal or the driving signal to the switch T6 in the second half of the first control period.
  • the switch T6 is in an on state
  • the switch T5 is in an off state
  • the power in the resonance unit 302 is transmitted to the output filtering unit 304 through the switch T6.
  • the plurality of control periods may include at least one first control period and at least one second control period.
  • the control operations performed by the control circuit 33 in different control cycles are different.
  • the control circuit 33 can make the first power supply 32 charge the resonance unit 302 and the resonance unit 302 charge the output filtering unit 304 by performing different control operations in different periods, and the two charging processes are alternately performed.
  • control circuit 33 may determine the voltage across the element through a conditioning circuit connected in parallel with the element. For example, the voltage of the capacitor C5 and the like are determined by a conditioning circuit in parallel with the capacitor C5 in the output filtering unit 304 .
  • the control circuit 33 can also determine the voltage across the element through an analog-digital sampling circuit connected in parallel with the element, such as the voltage of the capacitor C6 through an analog-digital sampling circuit connected in parallel with the capacitor in the resonance unit 302 .
  • the input filtering unit 305 may also store the electrical energy provided by the first power supply 32 . In scenarios where the input filtering unit 305 may include multiple sub-input filtering units.
  • the control circuit 33 may also use the sub-input filtering unit in the input filtering unit 305 as an energy transfer medium.
  • the control circuit 33 can control the switch unit 301 to transmit the electric energy in the sub-input filtering unit to the resonance unit 302 , so that the sub-input filtering unit in the input filtering unit 305 can charge the resonance unit 302 .
  • the charging voltage of the resonant unit 302 by the sub-input filtering unit is lower than the input voltage provided by the first power supply 32, and the current peak generated during charging is small, which can reduce the current impact on the switches in the circuit.
  • the input filtering unit 305 including two sub-input filtering units As shown in FIG. 7 , the two sub-input filtering units in the input filtering unit 305 are respectively denoted as a first sub-input filtering unit 305N1 and a second sub-input filtering unit 305N2.
  • the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2 are connected in series.
  • the input of the second sub-input filtering unit 305N2 is connected to the first input S1 of the RSCC 31, and the output of the second sub-input filtering unit 305N2 is connected to the input of the first sub-input filtering unit 305N1.
  • the output terminal of the first sub-input filtering unit 305N1 is connected to the second input terminal S2 and the input terminal 304a of the output filtering unit 304, respectively.
  • the first sub-input filtering unit 305N1 may include at least one capacitor connected in series.
  • the second sub-input filtering unit 305N2 may include at least one capacitor connected in series.
  • the first terminal 301a of the switch unit 301 is respectively connected to the first input terminal S1 of the RSCC 31 and the input terminal of the second sub-input filtering unit 305N2.
  • the second terminal 301b of the switch unit 301 is connected to the second input terminal S2.
  • the third end 301c of the switch unit 301 is connected to the first end 302a of the resonance unit 302 .
  • the fourth terminal 301 d of the switch unit 301 may be connected to the control circuit 33 .
  • the control circuit 33 can control the switch unit 301 .
  • the fifth terminal 301e of the switch unit 301 is respectively connected to the output terminal of the second sub-input filtering unit 305N2 and the input terminal of the first sub-input filtering unit 305N1. In other words, the fifth terminal 301e of the switch unit 301 is connected between the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2.
  • the first end 302a of the resonance unit 302 is connected to the third end 301c of the switch unit 301 , and the second end 302b of the resonance unit 302 is connected to the first input end 303a of the clamping unit 303 .
  • the first input end 303a of the clamping unit 303 is connected to the second end 302b of the resonance unit 302 .
  • the second input end 303b of the clamping unit 303 is connected to the output end S3 of the RSCC 31 .
  • the output terminal 303c of the clamping unit 303 is connected to the second input terminal S2 of the RSCC 31 .
  • the input terminal 304a of the output filtering unit 304 is connected to the output terminal 305b and the second input terminal S2 of the input filtering unit 305, respectively.
  • the output terminal 304b of the output filtering unit 304 is connected to the output terminal S3 of the RSCC 31.
  • the output filtering unit 304 may include at least one capacitor. Two poles of the first power supply 32 are respectively connected to the first input end S1 and the second input end S2 of the RSCC 31 .
  • the control circuit 33 may control the switch unit 301 to open the circuit between the first input terminal S1 and the second input terminal S1.
  • the open circuit between the input terminals S2 causes the switch unit 301 to stop transmitting power.
  • a path is formed between the first power supply 32 and the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2, and the first power supply 32 can charge the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2.
  • control circuit 33 may control the circuit breaker between the switch unit 301 and the second sub-input filtering unit 305N2, and the circuit breaker between the switch unit 301 and the second input end S2 of the RSCC 31, that is, the control circuit 33 controls the circuit breaker in the RSCC 31.
  • the switching unit 301, the resonance unit 302, the clamping unit 303 and the output filtering unit 304 are disconnected, so that the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2 are connected in series between the two poles of the first power supply 32, so that the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2 are connected in series.
  • FIG. 8 shows the on and off conditions in the conversion circuit during the charging process of the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2, wherein the thick line shows the conducting part and the dashed line shows the off-circuit part.
  • the control circuit 33 may control the switch unit 301 to filter the first sub-input filtering unit 305N1 and the second sub-input
  • the power in any one of the sub-input filtering units in the unit 305N2 is transmitted to the resonance unit.
  • the control circuit 33 controls the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 to the resonance unit 302 , so that the first sub-input filtering unit 305N1 can charge the resonance unit 302 .
  • the power in the first sub-input filtering unit 305N1 is less than the power provided by the first power supply 32, and the resonant unit 302 is charged by the first sub-input filtering unit 305N1, which can reduce the current generated in the circuit.
  • the control circuit 33 controls the switch unit 301 to transmit the power in the first sub-input filter unit 305N1 to the resonance unit 302, the control circuit 33 can control the on-off state of each switch in the switch unit 301 to make the first sub-input filter unit 305N1 , a fourth channel is formed between the switch unit 301, the resonance unit 302, and the clamping unit 303, the circuit between the switch unit 301 and the first input S1 is open, and the circuit between the switch unit 301 and the second input end S2 of the RSCC 31 is open, and the clamp The circuit between the bit unit 303 and the output filtering unit 304 is disconnected, and the first sub-input filtering unit 305N1 can charge the resonance unit 302 through the fourth channel.
  • the resonant unit 302 is charged by a part of the input filter units in the plurality of input filter units, which can reduce the impact of the current on the elements in the RSCC 31 during the charging process, and further protect the elements in the conversion circuit.
  • the control circuit 33 When the control circuit 33 controls the switch unit 301 to transmit the power provided by the first power supply 32 to the resonance unit 302, the control circuit 33 may also control the switch unit 301 to input the first sub-input filtering unit 305N1 and the second sub-input The power in the filtering unit 305N2 is transmitted to the resonance unit 302 for charging.
  • the control circuit 33 can control the on-off state of each switch in the switch unit 301, so that the first sub-input filtering unit 305N1, the second sub-input filtering unit 305N2, the switching unit 301, the resonance unit 302, and the clamping unit 303 form a first sub-input filtering unit.
  • FIG. 10 shows the channel and disconnection conditions in the RSCC 31 when the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2 charge the resonance unit 302 together, wherein the thick line shows the fifth channel, and the dashed line shows the fifth channel. out of the circuit breaker.
  • control circuit 33 When the control circuit 33 controls the switch unit 301 to transmit the power provided by the first power source 32 to the resonance unit 302 , the control circuit 33 may also control the switch unit 301 to transmit the power provided by the first power source 32 to the resonance unit 302 middle.
  • a path is formed between the first power supply 32 , the switch unit 301 , the resonance unit 302 , and the clamp unit 303 , the switch unit 301 and the second input end S2 are disconnected, and the clamp unit 303 and the output end Open circuit between S3.
  • the control circuit 33 controls the switching unit 301 to transmit the electric energy in the resonance unit 302 to the output filtering unit 304
  • the control circuit 33 can control the switching unit 301 to transmit the electric energy in the resonance unit 302 and the first sub-input filtering unit 305N1 to the output filtering unit 304.
  • the resonance unit 302 and the first sub-input filtering unit 305N1 can be implemented to charge the output filtering unit 304.
  • the control circuit 33 can control the on-off state of each switch in the switch unit 301, so that the first sub-input filter unit 305N1, the switch unit 301, the resonance unit 302, the clamp unit 303, and the output filter unit 304 form a sixth channel, the switch unit
  • the circuit between the second terminal 301b of the 301 and the second input terminal S2 of the RSCC 31 is disconnected, and the circuit between the first terminal 301a of the switch unit 301 and the first input terminal S1 of the RSCC 31 is disconnected.
  • the resonance unit 302 and the first sub-input filtering unit 305N1 charge the output filtering unit 304 through the sixth channel.
  • Figure 11 shows the channel and open circuit conditions in the RSCC 31 during the charging process of the resonant unit 302 and the first sub-input filtering unit 305N1 to the output filtering unit 304, wherein the thick line shows the sixth channel, and the dashed line shows the open circuit part.
  • control circuit 33 controls the switching unit 301 to transmit the electric energy in the resonance unit 302 to the output filtering unit 304
  • the control circuit 33 can control the switching unit 301 to transmit the electric energy in the resonance unit 302 to the output filtering unit 304, and the resonance unit can be realized 302 charges the output filtering unit 304 .
  • the control circuit 33 can control the on-off state of each switch in the switch unit 301, so that the resonance unit 302, the switch unit 301, the output filter unit 304 and the clamp unit 303 form a seventh channel, and the first end 301a of the switch unit 301 is connected to the RSCC 31 is disconnected between the first input end S1, the second end 301b of the switch unit 301 and the second input end S2 of the RSCC 31 are disconnected, and the fifth end 301e of the switch unit 301 is disconnected from the first sub-input filtering unit 305N1 road.
  • FIG. 12 shows the channel and disconnection conditions in the RSCC 31 during the charging process of the resonant unit 302 to the output filtering unit 304, wherein the thick line shows the seventh channel, and the dashed line shows the disconnection part.
  • the switch unit 301 in this embodiment of the present application may further include a switch T7 , a switch T8 , a diode D7 and a diode D8 .
  • One end of the switch T7 is respectively connected to the switch T5 and the cathode of the diode D8, and one end of the switch T7 not connected to the switch T5 can be used as the first end 301a of the switch unit 301, and is connected to the first input end S1 of the RSCC 31.
  • One end of the switch T8 is connected to the anode of the switch T6 and the diode D7 respectively, and one end of the switch T8 not connected to the switch T6 can be used as the second end 301b of the switch unit 301, and is connected to the second input end S2 of the RSCC 31.
  • the first node M1 between the switch T5 and the switch T6 may be the third terminal 301 c of the switch unit 301 .
  • the anode of diode D8 is connected to the cathode of diode D7.
  • the connection point between the cathode of the diode D7 and the anode of the diode D8 in the switch unit 301 may serve as the fifth terminal 303 e of the switch unit 301 .
  • the control circuit 33 can control all the four switches in the switch unit 301 to be in the off state, that is, the control circuit 33 controls the switch T7, the switch T5, the switch T6, and the switch T8 to be in the off state, so as to control the switch unit 301 to stop transmission. power, so that the first power supply 32 can charge the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2.
  • the control circuit 33 can control the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 to the resonance unit 302 by controlling the switch T7, the switch T6, the switch T8 to be in an off state, and the switch T5 to be in an on state,
  • the first sub-input filtering unit 305N1 can be made to charge the resonance unit 302 .
  • the control circuit 33 can also control the switch T6 and the switch T8 to be in the off state by the switch T7 and the switch T5 being in the on state, so that the control switch unit 301 can control the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2.
  • the power is transmitted to the resonance unit 302, so that the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2 can charge the resonance unit 302 together.
  • the control circuit 33 can control the switch T7, the switch T5, and the switch T8 to be in an off state, and control the switch T6 to be in an on state, so that the switch unit 301 can transmit the electrical energy in the resonance unit 302 and the first sub-input filtering unit 305N1 to the output filtering unit.
  • the unit 304 can make the resonance unit 302 and the first sub-input filtering unit 305N1 charge the output filtering unit 304 together.
  • the control circuit 33 can also control the switch T7 and the switch T5 to be in the off state, and control the switch T6 and the switch T8 to be in the on state, so that the switch unit 301 transmits the power in the resonance unit 302 to the output filter unit 304, so that the resonance unit can be 302 charges the output filtering unit 304 .
  • control circuit 33 can change the voltage at the first node M1 in the switch unit 301 and the voltage at the second node M2 in the clamp unit 303 by controlling the conduction state of each switch in the switch unit 301 .
  • the switch T7 and the switch T5 are in the on state
  • the switch T6 and the switch T8 are in the off state
  • the voltage value at the first node M1 is equal to the voltage value of the first input terminal S1
  • the voltage value at the second node M2 is equal to the first The voltage value of the two input terminals S2.
  • the resonance unit 302 may be charged by the first power supply 32, or the resonance unit 302 may be charged by the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2 together.
  • the switch T6 is in the on state, the switch T5, the switch T7 and the switch T8 are in the off state, the voltage value at the first node M1 is equal to the voltage of the node between the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N1, The voltage value at the second node M2 is equal to the voltage value of the second input terminal S2.
  • the resonance unit 302 may be charged by the first sub-input filtering unit 305N1.
  • the resonant unit 302 is in a charged state, the switches for transmitting power in the resonant unit 302 are different, and the voltage source at the first node M1 has various possibilities.
  • the output filtering unit includes a plurality of sub-output filtering units, and there are more ways for the resonance unit 302 to be charged. Therefore, the control circuit 33 also has more control modes for controlling the switching unit 301 to transmit the power provided by the first power source 32 to the resonance unit 302 .
  • the switch T7, the switch T5 and the switch T8 are in the off state
  • the control switch T6 is in the on state
  • the voltage value at the first node M1 is equal to that between the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N1
  • the voltage of the node, the voltage value at the second node M2 is equal to the voltage value of the output terminal 304 b of the output filtering unit 304 .
  • the resonance unit 302 and the first sub-input filtering unit 305N1 charge the output filtering unit 304 together.
  • the switch T7 and the switch T5 are in the off state, the control switch T6 and the switch T8 are in the on state, the voltage value at the first node M1 is equal to the voltage value of the second input terminal S2, and the voltage value at the second node M2 is equal to the output filter The voltage value at the output 304b of the cell 304 .
  • the resonance unit 302 charges the output filtering unit 304 .
  • the output filter unit 304 is in a charged state, and the switches in the resonance unit 302 for transmitting the power provided by the resonance unit 302 are different, and the power in the resonance unit 302 is transmitted to other
  • the unit for example, the first sub-input filtering unit 305N1, and the output filtering unit 304.
  • the output filtering unit includes a plurality of sub-output filtering units, and the output filtering unit 304 is charged in more ways. Therefore, the control circuit 33 also has more control methods for controlling the switching unit 301 to transmit the power in the resonance unit 302 to the output filtering unit 304 .
  • control circuit 33 can finely control the charging process of the output filtering unit 304 by using the aforementioned various control operations.
  • control circuit 33 first controls the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 to the resonance unit 302, and the first sub-input filtering unit 305N1 charges the resonance unit 302, and the first sub-input filtering unit 305N1 charges the resonance unit 302.
  • the electric energy is less than that provided by the first power source 32 , and the current generated during the charging of the resonance unit 302 is smaller.
  • the first power source 32 directly charges the current during the charging process of the resonance unit 302 .
  • the resonance unit 302 is charged by the first sub-input filtering unit 305N1, a certain amount of electric energy is stored in the resonance unit 302, and the current during the charging of the resonance unit 302 by the first power supply 32 is smaller to avoid impact on the switch unit 301.
  • the control circuit 33 may perform any one of the aforementioned control operations for charging the resonance unit 302 , and may also perform any one of the aforementioned control operations for charging the output filtering unit 304 .
  • the period of performing the control operation in which the resonance unit 302 is charged does not overlap with the period in which the control operation in which the output filtering unit 304 is charged is performed.
  • control circuit 33 may control the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2 to the resonance unit 302 in the first half cycle of the first control cycle.
  • the control circuit 33 may control the resonant unit 302 to control the switch unit 301 to transmit the power in the resonant unit 302 to the output filter unit 304 in the second half of the first control cycle.
  • the control circuit 33 may control the switch unit 301 to transmit the power in the first sub-input filtering unit 305 and the power in the resonance unit 302 to the output filtering unit 304 in the second half of a control cycle.
  • control circuit 33 may control the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 to the resonance unit 302 in the first half cycle of the second control cycle.
  • the control circuit 33 may control the switch unit 301 to transmit the power in the resonance unit 302 to the output filter unit 304 in the second half cycle of the second control cycle.
  • the control circuit 33 may control the switching unit 301 to transmit the power in the first sub-input filtering unit 305 and the power in the resonance unit 302 to the output filtering unit 304 together in the second half of the second control period.
  • the control circuit 33 can also perform any one of the aforementioned control operations for charging the resonance unit 302 and perform any one of the aforementioned control operations for charging the output filtering unit 304 multiple times. Wherein, the period of performing the control operation in which the resonance unit 302 is charged does not overlap with the period in which the control operation in which the output filtering unit 304 is charged is performed. Between adjacent two control operations performed by the control circuit 33 for the resonant unit 302 to be charged, the control circuit 33 performs one control operation for the output filter unit 304 to be charged.
  • control circuit 33 may control the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2 to the resonance unit during the first period of the first half of the third control cycle. 302.
  • the switching unit 301 is controlled to transmit the power in the first sub-input filtering unit 305N1 to the resonance unit 302 .
  • the control circuit 33 may control the resonance unit 302 to control the switch unit 301 to transmit the power in the resonance unit 302 to the output filter unit 304 during the second period of the first half of the first control cycle.
  • control the switch unit 301 to transmit the power in the first sub-input filtering unit 305 and the power in the resonance unit 302 to the output filtering unit 304 .
  • the control circuit 33 may control the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2 to the resonance unit 302 during the third period of the second half of the third control cycle.
  • the switching unit 301 is controlled to transmit the power in the first sub-input filtering unit 305N1 to the resonance unit 302 .
  • the control circuit 33 may control the resonance unit 302 to control the switch unit 301 to transmit the power in the resonance unit 302 to the output filter unit 304 in the fourth period of the second half of the first control period.
  • control the switch unit 301 to transmit the power in the first sub-input filtering unit 305 and the power in the resonance unit 302 to the output filtering unit 304 .
  • control circuit 33 can also control the switch unit 301 more finely to transmit the power provided by the first power supply 32 to the output filter unit 304 .
  • the following embodiments of the present application provide a control method, which can be applied to the conversion circuit corresponding to FIG. 7 .
  • the method may include multiple steps, and the control circuit may execute at least one step in one control cycle.
  • the control circuit can also perform a step multiple times within a control cycle. As shown in Figure 14, the method includes the following steps:
  • step S1401 the control circuit 33 controls the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 to the resonance unit 302 until the voltage of the resonance unit 302 is greater than the first preset threshold.
  • the control switch unit 301 can be controlled to transmit the power provided by the first power supply 32 to the output filter unit 304 by executing a preconfigured control operation.
  • the control circuit 33 may first perform the control operation of step S1401, so that the voltage of the resonance unit 302 is greater than the first preset threshold, which can reduce the current spikes generated in the subsequent charging process.
  • the first preset threshold may be a minimum value within the first voltage range.
  • Step S1402 the control circuit 33 performs operation 1 and operation 2 according to the first preset mode.
  • operation 1 is to control the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 and the power in the second sub-input filtering unit 305N2 to the resonance unit 302
  • operation 2 is to control the switch unit 301 to transfer the power in the resonance unit 302 to the resonance unit 302 .
  • the electrical energy of the first sub-input filtering unit 305N1 is transmitted to the output filtering unit 304 .
  • the first preset mode may be an alternate mode of "operation 1, operation 2, operation 1, operation 2".
  • the control circuit 33 may control the duration for which operation 1 is performed. For example, by controlling the duration of the high-level pulse or controlling the duration of the low-level pulse, the duration of the control operation 1 can be controlled, that is, the control of the first sub-input filtering unit 305N1 and the second sub-input filtering unit 305N2 to resonate The duration for which the unit 302 is charged. Similarly, the control circuit 33 may also control the duration of other charging operations.
  • the first preset mode may also be an alternate mode of "operation 2, operation 1, operation 2, operation 1 --.
  • the control circuit 33 uses the first sub-input filtering unit 305N1 and the resonance unit 302 as an intermediate medium for energy transmission, and performs a control operation according to the first preset mode, which can transfer the energy in the second sub-input filtering unit 305N2 to the output filtering unit 304. , it can also be understood that the second sub-input filtering unit 305N2 charges the output filtering unit 304 . In step S1402, the voltage of the second sub-input filtering unit 305N2 decreases, and the voltage of the first sub-input filtering unit 305N1 increases.
  • step S1403 the control circuit 33 determines whether the voltage of the output filtering unit 304 is greater than the second preset threshold, if not, the next step is to perform step S1404, and if so, the next step is to perform step S1405.
  • the control circuit 33 may monitor the voltage of the output filtering unit 304 in the process of performing the operation 1 and the operation 2 alternately. If the voltage of the output filtering unit 304 is greater than the second preset value, it may be considered that the preliminary charging of the output filtering unit 304 to the second sub-input filtering unit 305N2 is completed.
  • the second preset threshold may be a minimum value within the second voltage range.
  • the value in the third voltage range may be any value close to the voltage value of 0.3 times the output voltage Vin of the first power supply 32 .
  • the minimum value in the third voltage range may be 0.3Vin
  • the second voltage range may be [0.3Vin, Vin].
  • the second voltage range may also consist of discrete values, such as ⁇ 0.3Vin, 0.31Vin, 0.315Vin, 0.35Vin ⁇ .
  • the numerical range of the voltage value close to 0.3 times the output voltage Vin of the first power supply 32 can be configured according to the component parameters in the RSCC 31 .
  • step S1404 the control circuit 33 determines whether the voltage of the first sub-input filtering unit 305N1 is greater than the third preset threshold, if yes, the next step is to perform step S1402, if not, the next step is to perform step S1405.
  • the control circuit 33 may also monitor the voltage of the first sub-input filtering unit 305N1 in the process of alternately performing the operation 1 and the operation 2.
  • the third preset threshold may be the minimum value within the second voltage range.
  • the minimum value in the second voltage range can be determined according to the input voltage Vin provided by the first power supply 32 and the preset threshold ref.
  • the preset threshold ref is 30V
  • the minimum value of the second voltage range may be (0.5Vin+30)V.
  • the second voltage range may be [0.5Vin+ref, Vin].
  • the second voltage range may also be composed of discrete values, eg, ⁇ 0.48Vin+ref, 0.485Vin+ref, 0.5Vin+ref ⁇ .
  • the preset threshold ref may be configured according to the parameters of the components in the RSCC 31 or the scene of applying the conversion circuit.
  • the preset threshold ref may also be determined according to a test situation of the influence of precharging on the working performance of the conversion circuit. Exemplarily, Vin is 1500V, ref is 30V, and the third threshold may be 780V.
  • operation 1 and operation 2 may also be alternately performed by the control circuit 33 until the voltage of the first sub-input filtering unit 305N1 is within the second voltage range.
  • the control circuit 33 may alternately perform operation 1 and operation 2 until the voltage of the first sub-input filtering unit 305N1 is greater than the second preset threshold.
  • This embodiment of the present application does not specifically limit the order in which steps S1403 and S1404 are executed.
  • step S1405 the control circuit 33 determines whether the voltage of the resonance unit 302 is greater than the sum of the voltage of the output filtering unit 304 and the voltage of the first sub-input filtering unit 305N1.
  • the control circuit 33 can also monitor the voltage of the resonance unit 302. If it is determined that the voltage of the resonance unit 302 is greater than the sum of the voltage of the output filter unit 304 and the voltage of the first sub-input filter unit 305N1, the control circuit 33 can control the switch unit 301 to switch the power in the resonance unit 302. and the power in the first input power supply is transmitted to the output filtering unit 304 . Conversely, if the control circuit 33 determines that the voltage of the resonance unit 302 is less than or equal to the sum of the voltage of the input filter unit and the voltage of the first sub-input filter unit 305N1, it can control the switch unit 301 to transmit the power in the first sub-input filter unit 305N1 to the resonance unit. 302.
  • Step S1406 the control switch unit 301 transmits the power in the resonance unit 302 and the power in the first sub-input filtering unit 305N1 to the output filtering unit 304 until the voltage of the resonance unit 302 is less than or equal to the voltage of the output filtering unit 304 and the first sub-filter unit 304.
  • the control circuit 33 uses the first sub-input filtering unit 305N1 as an energy transmission medium, so that the energy in the resonance unit 302 can be transmitted to the output filtering unit 304, the voltage of the resonance unit 302 decreases, and the voltage of the output filtering unit 304 increases .
  • step S1407 the control circuit 33 executes operation 3 and operation 4 according to the second preset mode, wherein operation 3 is to control the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 to the resonance unit 302, and operation 3 is:
  • operation 3 is to control the switch unit 301 to transmit the power in the first sub-input filtering unit 305N1 to the resonance unit 302, and operation 3 is:
  • the control switch unit 301 transmits the power in the resonance unit 302 to the output filter unit 304 .
  • step S1406 When the control circuit 33 performs step S1406, the voltage of the resonance unit 302 drops, and the voltage value of the resonance unit 302 drops to less than or equal to the sum of the voltage of the output filtering unit 304 and the voltage of the first sub-input filtering unit 305N1, the resonance unit 302 cannot continue to The energy is transmitted to the output filtering unit 304, and the output filtering unit 304 cannot be charged.
  • the control circuit 33 performs operation 3 to boost the voltage of the resonance unit 302 .
  • the control circuit 33 performs operation 4 to cause the resonance unit 302 to charge the output filtering unit 304 .
  • the second preset mode may be an alternate mode of "operation 3, operation 4, operation 3, operation 4".
  • the control circuit 33 can control the duration of performing the operation 3, for example, by controlling the duration of the high-level pulse or the duration of the low-level pulse, so as to control the duration of the operation 3. Similarly, the control circuit 33 may also control the duration of operation 4 .
  • the second preset mode may also be an alternate mode of "operation 4, operation 3, operation 4, operation 3".
  • the control circuit 33 uses the resonance unit 302 as an intermediate medium for energy transmission, and performs the control operation according to the second preset mode, which can transfer the energy in the first sub-input filtering unit 305N1 to the output filtering unit 304, and can realize the first sub-input filtering.
  • Unit 305N1 charges output filtering unit 304 .
  • the control circuit 33 performs step S1407, the voltage of the first sub-input filtering unit 305N1 decreases, and the voltage of the output filtering unit 304 increases.
  • step S1408 the control circuit 33 determines whether the voltage of the output filtering unit 304 is greater than the second preset threshold. If not, the next step is to perform step S1409. If yes, the next step is to perform step S1410.
  • step S1407 the execution of step S1407 can be ended, and step S1410 can be executed. If the control circuit 33 determines that the voltage of the output filtering unit 304 is less than or equal to the second preset threshold, the determination process of step S1409 may be performed.
  • step S1409 the control circuit 33 determines whether the voltage of the first sub-input filtering unit 305N1 is less than or equal to the third preset threshold.
  • step S1407 when the control circuit 33 executes steps S1408 and S1409, step S1407 may also be executed. In other words, the control circuit 33 may also execute steps S1408 and S1409 during the process of executing step S1407.
  • step S1410 the control circuit 33 determines whether the voltage of the resonance unit 302 is greater than the fourth preset threshold, if yes, the next step is to perform step S1411, and if not, the next step is to perform step S1412.
  • the fourth preset threshold may be a value greater than half of the input voltage Vin of the first power supply 32 , for example, 0.55 Vin.
  • Step S1411 the control circuit 33 controls the switch unit 301 to transmit the power in the resonance unit 302 to the output filter unit 304 until the voltage of the resonance unit 302 is greater than or equal to the first preset threshold.
  • step S1412 the control circuit 33 determines whether the voltage of the resonance unit 302 is less than the first preset threshold value, if yes, the next step is to perform step S1413, if not, the next step is to perform step S1414.
  • Step S1413 the control circuit 33 controls the switch unit 301 to transmit the power in the resonance unit 302 and the power in the first sub-input filtering unit 305N1 to the output filtering unit 304 .
  • Step S1414 the control circuit 33 performs operations 5 and 6 according to the third preset mode, until the voltage of the output filtering unit 304 is greater than the input voltage provided by the first power supply 32, wherein the operation 5 is to control the switch unit 301 to input the first sub-input.
  • the power in the filtering unit 305N1 and the power in the second sub-input filtering unit 305N2 are transmitted to the resonance unit 302 , and operation 6 is to control the switch unit 301 to transmit the power in the resonance unit 302 to the output filtering unit 304 .
  • step S1415 the control circuit 33 determines whether the voltage of the output filtering unit 304 is greater than or equal to the input voltage provided by the first power supply 32. If yes, step S1414 is performed next; if not, step S1416 is performed next.
  • step S1416 the control circuit 33 controls the switch unit 301 to make the RSCC 31 in a working state.
  • the control circuit 33 can control the switch unit 301 to control the RSCC 31 to output the target voltage, so that the conversion circuit is in a working state.
  • the sequence between the steps is only used as an example, and not as a specific limitation on the sequential execution sequence of the steps.
  • the embodiment of the present application also provides another control method, which can be applied to the conversion circuit corresponding to FIG. 13 .
  • the method may include multiple steps, and the control circuit 33 may execute at least one step in one control cycle.
  • the method may include multiple steps, and the control circuit 33 may execute at least one step in one control cycle.
  • the control circuit 33 may also execute a step multiple times within one control cycle. As shown in Figure 15, the method includes the following steps:
  • Step S1501 the control circuit 33 sends a control signal with a pulse width of a preset duration to the switch T5 in each control cycle until the voltage of the resonance unit 302 is greater than the first preset threshold.
  • the control circuit 33 can control the switch to be turned on by sending a pulse signal to the switch.
  • the control circuit 33 may control the switch to be turned on by not sending a pulse signal to the switch.
  • the control circuit 33 sends a pulse signal to the switch to control the switch to be turned on as an example to introduce the embodiment of the present application, and not as a specific limitation to the embodiment of the present application.
  • step S1501 performed by the control circuit 33, the switch T5 is in the conducting state after receiving the control signal, and the switch T5 may remain in the conducting state until no control signal is received.
  • the control switch T7, the switch T6, and the switch T8 are in an off state in each control cycle.
  • the preset duration is less than the duration of one control period.
  • the duration of one control period may be 55 microseconds, the preset duration may be 1.8%*55 microseconds, and the preset duration may also be 2%*55 microseconds.
  • the preset duration may be located in the first half of a control cycle, or in the second half of the cycle.
  • the switch T5 is in an on state, and the other switches are in an off state.
  • the switch unit 301 transmits the power in the first sub-input filtering unit 305N1 to the resonance unit 302 .
  • the control circuit 33 can send a control signal with a pulse width of a preset duration to the switch T5 for many times, so that the voltage of the resonance unit 302 gradually increases until the voltage of the resonance unit 302 is greater than the first preset threshold, and the control circuit 33 can execute the steps.
  • the first preset threshold may be a minimum value within the first voltage range.
  • control circuit 33 may control all switches in the switch unit 301 to be in an off state, so that the first power supply 32 charges the first sub-input filtering unit 305N1.
  • Step S1502 the control circuit 33 continues to send a control signal to the switch T5 in the first control cycle, sends a control signal with a pulse width of a preset duration to the switch T7 during the first period, and sends a pulse width of a pulse width to the switch T6 during the second period.
  • a control signal with a preset duration wherein the first control period includes at least one first period and at least one second period, and the first period and the second period have no intersection.
  • the control circuit 33 can control the switch T5 to be in an on state in the first control period, and control the switch T8 to be in an off state in the first control period.
  • the control circuit 33 can control the switch T7 to be in an on state during a first period of time in the first control cycle, control the switch T6 to be in an on state during a second period of time in the first control cycle, and there is no connection between the first period and the second period. intersection.
  • the first control period may also include a plurality of first time periods and a plurality of second time periods.
  • the first first period can be before the first second period or after the first second period. Between two adjacent first time periods, there is a second time period.
  • the control circuit 33 may control the switch T7 and the switch T6 to alternately be in a conducting state in the first control period. When the switch T7 is in the ON state, the switch T6 may be in the OFF state. When the switch T7 is in the off state, the switch T6 may be in the on state.
  • the control circuit 33 controls the switch T5 to be in the on state, the switch T8 in the off state, the switch T7 in the on state, and the switch T6 in the off state.
  • the power in the first sub-input filtering unit 305N1 and the power in the second sub-input filtering unit 305N2 are transmitted to the resonance unit 302 .
  • the control circuit 33 controls the switch T5 to be in the on state, the switch T8 in the off state, the switch T7 in the off state, and the switch T6 in the on state, the switch T5 and the switch T6 can filter the first sub-input
  • the power in unit 305N1 and the power in resonance unit 302 are transferred to output filter unit 304 .
  • step S1503 it is determined whether the voltage of the output filtering unit 304 is greater than the second preset threshold value, if not, the next step is to perform step S1504, and if yes, the next step is to perform step S1505.
  • the control circuit 33 may collect the voltage of the output filtering unit 304 through the collecting device during the process of executing step S1502, and determine the magnitude relationship between the voltage of the output filtering unit 304 and the second preset threshold. In other words, step S1503 and step S1502 can be processed in parallel.
  • step S1504 the control circuit 33 determines whether the voltage of the first sub-input filtering unit 305N1 is greater than the third preset threshold.
  • the control circuit 33 may collect the voltage of the first sub-input filtering unit 305N1 through the acquisition device during the process of executing step S1502, and determine the magnitude relationship between the voltage of the first sub-input filtering unit 305N1 and the third preset threshold. In other words, steps S1504, S1502, and S1503 can be processed in parallel. The control circuit 33 may execute step S1504 in parallel after executing step S1502.
  • step S1502 If the voltage of the first sub-input filtering unit 305N1 is greater than the third preset threshold, the control circuit 33 performs the operation in step S1502 again.
  • the control circuit 33 performs the control operation of step S1502 in the next control cycle, that is, the next control cycle is regarded as the first control cycle.
  • the control circuit 33 executes steps S1503 and S1504 to determine the timing to end the execution of step S1502 by judging that the voltage of the output filtering unit 304 or the voltage of the first sub-input filtering unit 305N1 satisfies the conditions.
  • This embodiment of the present application provides two conditions for determining that the execution of step S1502 is ended.
  • the control circuit 33 may determine to end the execution of step S1502 only by judging that the voltage of the output filtering unit 304 satisfies the condition, or determine to end the execution of step S1502 only by judging that the voltage of the first sub-input filtering unit 305N1 satisfies the condition.
  • the control circuit 33 may execute step S1503 after executing step S1502. Or after step S1502 is performed, step S1504 is performed.
  • step S1505 the control circuit 33 determines whether the voltage of the resonance unit 302 is greater than the sum of the voltage of the output filtering unit 304 and the voltage of the first sub-input filtering unit 305N1.
  • Step S1506 in each control cycle, the control circuit 33 sends a control signal to the switch T6 and sends a control signal with a pulse width of a preset duration until the voltage of the resonance unit 302 is less than or equal to the voltage of the output filtering unit 304 and the first sub-input filtering unit. The sum of the 305N1 voltages.
  • the control circuit 33 may control the switch T7 , the switch T5 and the switch T8 to be in an off state in each control cycle, and control the switch T6 to be in an on state in a preset period of time in each control cycle. As shown in FIG. 18 , the control circuit 33 continues to send a control signal to the switch T6 within a preset period in each control cycle, so that the switch T6 can be continuously turned on during the preset period, and the switch T6 can The energy in the resonance unit 302 is transmitted to the output filtering unit 304, so that the voltage of the output filtering unit 304 can be gradually increased.
  • steps S1505 and S1506 may determine that the resonance unit 302 charges the output filtering unit 304 when the resonance unit 302 has more power. If the resonant unit 302 has less power, the control circuit 33 may directly execute step S1507 to make the first sub-input filtering unit 305N1 charge the resonant unit 302 .
  • the voltage of the resonance unit 302 drops from a voltage greater than the sum of the voltage of the first sub-input filtering unit 305N1 and the voltage of the output filtering unit 304 to equal to the voltage of the first sub-input filtering unit 305N1 and the output filtering unit 304
  • the circuit is in a steady state, and the resonant unit 302 stops discharging.
  • step S1507 the control circuit 33 continues to send a control signal to the switch T6 in the second control cycle, sends a control signal with a pulse width of a preset duration to the switch T5 in the third period, and sends a pulse width to the switch T8 in the fourth period.
  • the switch T6 can be controlled to be in an on state in the second control period, and the switch T7 can be in an off state in the second control period.
  • the control circuit 33 may control the switch T5 to be in an on state for a third period of time in the second control period, and control the switch T8 to be in an on state for a fourth period of time in the second control period. Among them, there is no intersection between the third period and the fourth period.
  • the second control period may also include a plurality of third time periods and a plurality of fourth time periods.
  • the first third period can be before the first fourth period or after the first fourth period. Between two adjacent third time periods, there is a fourth time period.
  • the control circuit 33 may control the switch T5 and the switch T8 to alternately be in a conducting state in the second control period. When the switch T5 is in the ON state, the switch T8 may be in the OFF state. When the switch T8 is in the off state, the switch T5 may be in the on state.
  • the control circuit 33 controls the switch T6 to be in the on state, the switch T7 in the off state, the switch T8 in the on state, and the switch T5 in the off state, and the switch T6 and the switch T8 can resonate.
  • the power in unit 302 is passed to output filtering unit 304 .
  • the control circuit 33 controls the switch T6 to be in the on state, the switch T7 in the off state, the switch T8 in the off state, and the switch T5 in the on state, and the switch T5 can input the first sub-input to the filter unit 305N1
  • the power is transmitted to the output filtering unit 304 .
  • step S1508 the control circuit 33 determines whether the voltage of the output filtering unit 304 is greater than the second preset threshold, if not, the next step is to perform step S1509, and if so, the next step is to perform step S1510.
  • step S1507 the voltage of the output filtering unit 304, the voltage 305N2 of the second sub-input filtering unit 305N2, and the voltage of the first sub-input filtering unit 305N1 will all change. If the control circuit 33 determines that the voltage of the output filtering unit 304 is greater than the second preset threshold, the execution of step S1507 can be ended, and step S1510 can be executed. If the control circuit 33 determines that the voltage of the output filtering unit 304 is less than or equal to the second preset threshold, the determination process of step S1509 may be performed.
  • Step S1509 the control circuit 33 judges whether the voltage of the first sub-input filtering unit 305N1 is less than or equal to the third preset threshold, if so, the next step is to perform step S1501, if not, the next step is to perform step S1507.
  • step S1507 when the control circuit 33 executes steps S1508 and S1509, step S1507 may also be executed. In other words, the control circuit 33 may also execute steps S1508 and S1509 during the process of executing step S1507.
  • the control circuit 33 executes steps S1503 and S1504 in order to determine the timing to end the execution of step S1507 by judging that the voltage of the output filtering unit 304 or the voltage of the first sub-input filtering unit 305N1 satisfies the conditions.
  • This embodiment of the present application provides two conditions for determining that the execution of step S1507 is ended.
  • control circuit 33 may determine to end the execution of step S1507 only by judging that the voltage of the output filtering unit 304 satisfies the condition, or determine to end the execution of step S1507 only by judging that the voltage of the first sub-input filtering unit 305N1 satisfies the condition. In other words, the control circuit 33 may execute step S1508 after executing step S1507. Or after step S1507 is performed, step S1509 is performed.
  • step S1510 the control circuit 33 determines whether the voltage of the resonance unit 302 is greater than the fourth preset threshold, if yes, the next step is to perform step S1511, if not, the next step is to perform step S1512.
  • the fourth preset threshold may be a value greater than half of the input voltage Vin of the first power supply 32 , for example, 0.55 Vin.
  • step S1511 the control circuit 33 continues to send a control signal to the switch T6 and a control signal with a preset duration to the switch T8 in each control cycle until the voltage of the resonance unit 302 is less than or equal to the fourth preset threshold.
  • the control circuit 33 controls the switch T6 to be in the on state, the switch T7 in the off state, the switch T8 in the on state, and the switch T5 in the off state.
  • the power in the resonance unit 302 is transmitted to the output filter unit 304 .
  • the control circuit 33 controls the switch T6 and the switch T8 to transmit the power in the resonance unit 302 to the output filter unit 304 by executing step S1511 , and reduces the voltage across the resonance unit 302 .
  • the control circuit 33 may execute step S1511 after determining that the voltage of the resonance unit 302 is less than or equal to the fourth preset threshold.
  • step S1512 the control circuit 33 determines whether the voltage of the resonance unit 302 is lower than the first preset threshold value, if yes, the next step is to perform step S1513, if not, the next step is to perform step S1514.
  • step S1513 the control circuit 33 sends a control signal with a pulse width of a preset duration to the switch T5 in each control cycle until the voltage of the resonance unit 302 is greater than the first preset threshold.
  • step S1513 the switch T5 transmits the power in the first sub-input filtering unit 305N1 to the resonance unit 302, as shown in FIG. 16 .
  • the control circuit 33 may also monitor whether the voltage of the resonance unit 302 is between the first preset threshold and the fourth preset threshold during the execution of step S1513. If the control circuit 33 determines that the voltage of the resonance unit 302 is between the first preset threshold value and the fourth preset threshold value in the process of executing step S1513, step S1514 may also be directly executed.
  • the process of the control circuit 33 performing steps S1510 to S1512 can be understood as that the control circuit 33 adjusts the voltage value of the resonance unit 302 to be greater than the first preset threshold by controlling the switches in the switch unit 301 .
  • Step S1514 in the third control cycle, the control circuit 33 sends a control signal with a preset pulse width to the switch T5 and the switch T7 during the fifth period, and sends a pulse width of the preset period to the switch T6 and the switch T8 during the sixth period.
  • the control circuit 33 controls the switch T5 and the switch T7 to be in a conducting state during the fifth period in the third control cycle. As shown in FIG. 17 , the switch T5 and the switch T7 can input the first sub-input filter unit 305N1 with the electrical energy and the second The power in the sub-input filtering unit 305N2 is transmitted to the resonance unit 302 .
  • the control circuit 33 controls the switch T6 and the switch T8 to be in a conducting state during the sixth period in the third control cycle. As shown in FIG. 19 , the switch T6 and the switch T8 can transmit the power in the resonance unit 302 to the output filtering unit 304 .
  • step S1515 the control circuit 33 determines whether the voltage of the output filtering unit 304 is not less than the input voltage provided by the first power supply 32. If yes, the next step is to perform step S1514. If not, the next step is to perform step S1516.
  • step S1516 the control circuit 33 controls the switch unit 301 to make the RSCC 31 output the target voltage.
  • the control circuit 33 can control the switches in the switch unit 301 according to a preset control mode, so that the RSCC 31 can output the target voltage, thereby controlling the conversion circuit to be in a working state.
  • the conversion circuit and control method provided by the present application can be applied to scenarios using power electronic converters, such as photovoltaic power generation systems, electric vehicles, and renewable energy systems.
  • the first power source in the conversion circuit provided by the embodiment of the present application may include at least one photovoltaic string and a DC-DC boost circuit.
  • the DC-DC boost circuit is connected to the at least one photovoltaic string, and is used for boosting the voltage provided by the at least one photovoltaic string.
  • the output end of the DC-DC boost circuit can be used as the two poles of the first power supply to be connected to the first input end and the second input end of the RSCC, respectively, to provide an input voltage for the RSCC.
  • the application also provides a photovoltaic system, as shown in FIG. 21 , the system includes at least two photovoltaic strings, a Maximum Power Point Tracking (MPPT) combiner box, a DC-AC inverter circuit, and cables.
  • MPPT Maximum Power Point Tracking
  • the output end of the DC-AC inverter circuit is connected to the grid.
  • the photovoltaic power generation system also includes a control circuit, which can control the photovoltaic string, the MPPT combiner box and the DC-AC inverter circuit.
  • the MPPT combiner box can include two DC-DC boost circuits and one RSCC.
  • Each DC-DC boost circuit is connected to at least one PV string, the positive input terminal of the DC-DC boost circuit is connected to the positive terminal of the PV string, and the negative input terminal of the DC-DC boost circuit is connected to the negative terminal of the PV string connected.
  • the RSCC may be any RSCC provided in the foregoing embodiments.
  • the switch unit in the RSCC is connected with the control circuit.
  • the positive output terminal of one of the two DC-DC boost circuits is connected with the positive input terminal of the DC-AC inverter circuit.
  • the two DC-DC boost circuits are respectively denoted as a first DC-DC boost circuit and a second DC-DC boost circuit.
  • the positive output terminal of the second DC-DC boost circuit is connected to the positive input terminal of the DC-AC inverter circuit.
  • the negative output terminal of the second DC-DC boost circuit is connected to the zero-level terminal of the DC-AC inverter circuit.
  • the positive input terminal M1 of the RSCC is connected to the positive output terminal of the first DC-DC booster circuit, and the negative input terminal S2 of the RSCC is respectively connected to the negative output terminal of the first DC-DC booster circuit and the second DC-DC booster circuit.
  • the negative output terminal of the voltage circuit is connected.
  • the positive output terminal M4 of the RSCC is respectively connected to the negative output terminal of the second DC-DC boost circuit and the zero-level terminal of the DC-AC inverter circuit.
  • the negative output terminal M4 of the RSCC is connected to the negative input terminal of the DC-AC inverter circuit.
  • both the negative input terminal M2 and the positive output terminal M4 of the RSCC are connected to the negative output terminal of the second DC-DC boost circuit.
  • the negative input terminal M2 and the positive output terminal M4 of the RSCC may be the same terminal, such as the second input terminal S2 of the RSCC 31 in the foregoing embodiment.
  • the positive input terminal M1 of the RSCC may be the first input terminal S1 of the RSCC 31 .
  • the negative output terminal M3 of the RSCC can be the output terminal S3 of the RSCC 31 .
  • the first DC-DC boost circuit and the photovoltaic string connected to the first DC-DC boost circuit can be used as a power source to provide an input voltage for the RSCC.
  • the photovoltaic string connected to the first DC-DC boost circuit and the first DC-DC boost circuit can be used as the first power source in the foregoing embodiment to provide electrical energy for the RSCC.
  • the RSCC can be used to convert the input voltage provided by the first DC-DC boost circuit into a target voltage with opposite polarity, so as to protect the voltage from the first DC-DC boost circuit.
  • Component performance of PV strings connected to a voltage circuit can be used to convert the input voltage provided by the first DC-DC boost circuit into a target voltage with opposite polarity, so as to protect the voltage from the first DC-DC boost circuit.
  • the first DC-DC boost circuit and the photovoltaic string connected to the first DC-DC boost circuit may be regarded as the first DC-DC boost circuit in the foregoing embodiments.
  • the power supply provides an input voltage for the RSCC with the first DC-DC boost circuit.
  • the photovoltaic system provided by the implementation of the present application may include the conversion circuit provided in the foregoing embodiments.
  • the MMPT combiner box and the DC-AC inverter circuit in the photovoltaic system provided by the present application can form a string-type high-voltage inverter.
  • the photovoltaic system provided by the present application can also be regarded as a system including a string-type high-voltage inverter.
  • the photovoltaic system may include a DC-AC inverter circuit, multiple MPPT combiner boxes, and multiple photovoltaic strings.
  • the photovoltaic system can also be referred to as a photovoltaic power generation system based on a string high-voltage inverter.
  • Each MPPT combiner box includes an RSCC and two DC-DC boost circuits, wherein the two DC-DC boost circuits are a second DC-DC boost circuit and a first DC-DC boost circuit, respectively.
  • the positive output terminal of the RSCC in each MPPT combiner box is connected to the zero-level terminal of the DC-AC inverter circuit, and the negative output terminal of the RSCC is connected to the negative input terminal of the DC inverter circuit.
  • the positive output terminal of the second DC boost conversion circuit in each MPPT is connected to the positive input terminal of the DC-AC inverter circuit.
  • pre-charging the RSCC in each MPPT can protect the performance of components such as the output filter capacitor of the RSCC, and also ensure the working performance of the RSCC, so as to protect the working performance of the photovoltaic power generation system.
  • pre-charging the RSCC does not require additional components, which improves the power density of the RSCC, reduces the complexity of the photovoltaic power generation system, and simplifies the control process of the photovoltaic power generation system.
  • the photovoltaic system and photovoltaic power generation system provided by the embodiments of the present application can be applied to application scenarios of large-scale photovoltaic power plants, application scenarios of small and medium-sized distributed power plants, and application scenarios of household photovoltaic power generation systems.
  • Photovoltaic systems and photovoltaic power generation systems can convert light energy into direct current, and then convert direct current into alternating current to provide alternating current for loads or grids, also known as photovoltaic inverter systems, or photovoltaic inverter systems.

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Abstract

本申请提供一种变换电路、变换电路预充电控制方法及光伏系统，用于不增加额外成本，并避免在RSCC处于工作状态瞬间电路中产生电流对开关造成冲击，保障RSCC的工作性能。变换电路包括：第一电源、谐振开关电容变换器RSCC和控制电路。RSCC包括开关单元、输出滤波单元、第一输入端，第二输入端和输出端，开关单元连接在第一输入端和第二输入端之间，输出滤波单元连接在第二输入端和输出端之间。第一电源的一极与第一输入端连接，第一电源的另一极与第二输入端连接，第一电源用于为RSCC提供输入电压。控制电路与开关单元连接，用于在控制RSCC工作前，控制RSCC中的开关单元将第一电源提供的电能传输至输出滤波单元。

Description

一种变换电路、变换电路预充电控制方法及光伏系统 技术领域
本申请涉及电子技术领域，尤其涉及一种变换电路、变换电路预充电控制方法及光伏系统。
背景技术
传统直流变换器普遍采用电感、变压器等磁性元件传递能量，使传统直流变换器工作在硬开关状态。硬开关状态对直流变换器中开关损耗较大，降低了直流变换器的工作效率。并且电感、变压器等磁性元件体积较大，因而传统直流变换器功率密度较低。
为了提升直流变换器的性能，新型直流变换器被提出，如谐振开关电容变换器(resonant switched capacitor converter，RSCC)。RSCC中利用谐振单元传递能量，可使RSCC中的功率开关器件工作在软开关状态，提升RSCC的工作效率。谐振单元一般包括谐振电感和谐振电容，具相比于传统直流变换器中的电感、变压器等磁性元件，具有更小的体积，RSCC也因此具有较高的功率密度。
RSCC可以用于电压变换，如升压变换、降压变换、电压极性变换等应用场景。通常，RSCC包括多个开关管(开关)，多个电容，多个二极管和谐振单元，谐振单元通常包括谐振电感和谐振电容。图1中示出一种RSCC电路拓扑结构图。为RSCC提供输入电压后，通过控制多个开关的关断状态，可以实现输出目标电压。由于RSCC处于输出目标电压的工作状态之前，输出滤波电容的电压几乎为零。在RSCC处于工作状态的瞬间，谐振单元中谐振电感产生的电流对RSCC中的功率开关管造成冲击，影响开关管的性能，导致RSCC工作性能下降。
发明内容
本申请提供一种变换电路、变换电路预充电控制方法及光伏系统，用于不增加额外成本，并避免在RSCC处于工作状态瞬间电路中产生电流对开关造成冲击，保障RSCC的工作性能。
第一方面，本申请提供一种变换电路，包括：第一电源、谐振开关电容变换器RSCC和控制电路。所述RSCC包括开关单元、输出滤波单元、第一输入端S1，第二输入端S2和输出端S3，所述开关单元连接在所述第一输入端S1和所述第二输入端S2之间，所述输出滤波单元连接在所述第二输入端S2和所述输出端S3之间。所述第一电源的一极与所述第一输入端S1连接，所述第一电源的另一极与所述第二输入端S2连接，所述第一电源用于为所述RSCC提供输入电压。所述控制电路与所述开关单元连接，用于在控制所述RSCC工作前，控制所述RSCC中的所述开关单元将所述第一电源提供的电能传输至所述输出滤波单元。
本申请实施例中，变换电路中的RSCC可用于直流-直流变换场景中，如直流-直流变换电路，可以进行升压变换、降压变换或者极性变换等。变换电路中的控制电路可以控制RSCC工作。控制电路在控制RSCC工作前，控制RSCC中的开关单元将第一电源提供的电能传输至输出滤波单元中，提升输出滤波单元的电压。由于输出滤波单元中存储有电能， 其电压不为零。控制电路在控制RSCC工作的瞬间，电路中形成的电流较弱，对RSCC中的开关单元影响较弱，可以保障开关单元的性能。控制电路通过控制RSCC中的开关单元，可使第一电源对输出滤波单元充电，提升输出滤波单元的电压，并且不需要增加额外的充电电路，也可以保障RSCC的功率密度。
一种可能的设计中，所述RSCC还包括谐振单元和钳位单元。所述钳位单元与所述输出滤波单元并联。所述开关单元与所述谐振单元的一端连接，所述谐振单元的另一端与所述钳位单元连接。所述控制电路控制所述RSCC中的开关单元将所述第一电源提供的电能传输至所述输出滤波单元时，具体用于：控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元；控制所述开关单元将所述谐振单元中的电能传输至所述输出滤波单元。
本申请实施例中，控制电路可以通过控制开关单元将第一电源提供的能量传输至谐振单元中，可使第一电源对谐振单元充电。然后在控制开关单元将谐振单元中电能传输至输出滤波单元，可使谐振单元对输出滤波单元充电。由于谐振单元和输出滤波单元中存储有电能，谐振单元电压不为零，输出滤波单元电压不为零，可以降低RSCC工作的瞬间，电路中形成的电流。
一种可能的设计中，所述控制电路控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元时，所述第一电源、所述开关单元、所述谐振单元、所述钳位单元形成第一通路，所述开关单元和所述第二输入端S2之间断路，所述钳位单元与所述输出端S3之间断路。所述控制电路控制所述开关单元将所述谐振单元中的电能传输至所述输出滤波单元中时，所述开关单元、所述谐振单元、所述钳位单元、所述输出滤波单元形成第二通路，所述钳位单元与所述第二输入端S2之间断路。
本申请实施例中，RSCC中的谐振单元可以作为能量中转单元。控制电路控制开关单元将第一电源提供的电能传输至输出滤波单元过程中，可以先控制开关单元，使第一电源、开关单元、谐振单元、钳位单元形成第一通路，第一电源可以经由第一通路对谐振单元进行充电。然后控制电路控制开关单元，使开关单元、谐振单元、钳位单元和输出滤波单元形成第二通路，谐振单元可以经由第二通路对输出滤波单元进行充电。
一种可能的设计中，所述RSCC还包括输入滤波单元，所述输入滤波单元与所述开关单元并联。所述输入滤波单元用于存储所述第一电源提供的电能。所述输入滤波单元包括第一子输入滤波单元和第二子输入滤波单元，所述第一子输入滤波单元与所述第二子输入滤波单元串联连接，所述第一子输入滤波单元与所述第二子输入滤波单元连接的一端与所述开关单元连接。所述控制电路控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元时，具体用于：控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能传输至所述谐振单元中；或者，控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能和提供给所述第二子输入滤波单元中的电能传输至所述谐振单元中。
本申请实施例中，输入滤波单元与开关单元并联，输入滤波单元连接在第一电源的两极之间。第一电源可以将电能提供给输入滤波单元。输入滤波单元也可以存储第一电源提供的电能。RSCC中的输入滤波单元可以包括多个子输入滤波单元。控制电路在控制开关单元将第一电源提供的电能传输至谐振单元过程中，可以将输入滤波单元中的一个或多个子输入滤波单元做为能量中转单元。控制电路可以控制开关单元将一个或多个子输入滤波单元中的电能传输至谐振单元中。如，将第一子输入滤波单元中的能量传输至谐振单元中， 可以降低对谐振单元充电过程中产生电流对开关单元的冲击。控制电路将输入滤波单元中的一个或多个子输入滤波单元做为能量中转单元，可以灵活地，精细地对谐振单元进行充电。
一种可能的设计中，所述控制电路控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能传输至所述谐振单元中时，所述第一子输入滤波单元、所述开关单元、所述谐振单元、所述钳位单元之间形成第三通路，所述开关单元与所述第一输入端S1之间断路，所述开关单元与所述第二输入端S2之间断路，所述钳位单元与所述输出滤波单元断路。所述控制电路控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能和提供给所述第二子输入滤波单元中的电能传输至所述谐振单元中时控制所述开关单元将所述第一子输入滤波单元中的电能和所述第二子输入滤波单元电能传输至所述谐振单元中，所述第一子输入滤波单元、所述第二子输入滤波单元、所述开关单元、所述谐振单元、所述钳位单元之间形成第四通路，所述开关单元与所述第二输入端S2之间断路，所述钳位单元与所述输出滤波单元之间断路。
本申请实施例中，控制电路控制开关单元，使第一子输入滤波单元、开关单元、谐振单元、钳位单元之间形成给第三通路。第一子输入滤波单元可以经由第三通路对谐振单元进行充电。控制电路控制开关单元，所述第一子输入滤波单元、所述第二子输入滤波单元、所述开关单元、所述谐振单元、所述钳位单元之间形成第四通路。第一子输入滤波单元和第二子输入滤波单元可以经由第四通路对谐振单元进行充电。
一种可能的设计中，所述控制电路还用于控制所述开关单元将所述第一子输入滤波单元中的电能传输至所述输出滤波单元中。
本申请实施例中，控制电路可以通过控制开关单元，使谐振单元可以对输出滤波单元进行充电。控制电路还可以通过控制开关单元，使第一子输入滤波单元对输出滤波单元进行充电。控制电路可以将输入滤波单元中的子输入滤波单元作为能量中转单元，例如，第一子输入滤波单元对输出滤波单元进行充电，控制电路可以灵活地，精细地对输出滤波单元进行充电，保护变换电路中的元件。
一种可能的设计中，所述控制电路控制所述开关单元将所述谐振单元中的电能传输至所述输出滤波单元中时，所述谐振单元、所述开关单元、所述输出滤波单元和所述钳位单元形成第五通路，所述开关单元与所述第一子输入滤波单元之间断路，所述开关单元与所述第二输入端S2之间断路。
本申请实施例中，控制电路将RSCC中的谐振单元可以作为能量中转单元。控制电路可以在谐振单元被充电后，通过控制开关单元，使谐振单元、开关单元、输出滤波单元和钳位单元形成第五通路。谐振单元可以经由第五通路对输出滤波单元进行充电。
一种可能的设计中，所述控制电路控制所述开关单元将所述第一子输入滤波单元中的电能传输至所述输出滤波单元中时，所述第一子输入滤波单元、所述开关单元、所述谐振单元、所述钳位单元、所述输出滤波单元形成第六通路，所述开关单元与所述第二输入端S2之间断路，所述开关单元与所述第一输入端S1之间断路，所述钳位单元与所述第二输入端S2之间断路。
本申请实施例中，控制电路将RSCC中的谐振单元和第一子输入滤波单元作为能量中转单元。控制电路通过控制开关单元，使第一子输入滤波单元、开关单元、谐振单元、钳位单元、输出滤波单元形成第六通路。第一子输入滤波单元和谐振单元可以对输出滤波单 元进行充电。
一种可能的设计中，所述第一电源包括：至少一个光伏组串和第一直流-直流升压电路。所述至少一个光伏组串的正极与所述第一直流-直流升压电路的正极输入端连接，所述至少一个光伏组串的负极与所述第一直流-直流升压电路的负极输入端连接。所述第一直流-直流升压电路的正极输出端连接所述第一输入端S1，所述第一直流-直流升压电路的负极输出端连接所述第二输入端S2。所述第一直流-直流升压电路用于将所述至少一个光伏组串提供的电压转化为所述输入电压。
本申请实施例中，变换电路可以应用于光伏发电场景中。第一电源可以包括光伏组串和第一直流-直流升压电路。控制电路在控制RSCC工作前控制RSCC中的开关单元将第一电源提供的电能传输至输出滤波单元中，可以保障RSCC中开关单元的工作性能，从而保障光伏发电场景中变换电路的工作性能。
第二方面，本申请提供一种光伏系统，包括至少一个如第一方面中的变换电路、多个光伏组串、至少一个第二直流-直流升压电路、直流-交流逆变电路。每个第二直流-直流升压电路的正极输出端与所述直流-交流逆变电路的正极输入端连接，所述每个第二直流-直流升压电路的负极输出端分别与一个所述变换电路中的RSCC的第二输入端S2和所述直流-交流逆变电路的零电平端连接；其中，每个第二直流-直流升压电路的负极输出端连接不同所述变换电路中的RSCC的第二输入端S2。每个所述变换电路中的RSCC的输出端S3与所述直流-交流逆变电路的负极输入端连接。每个所述第二直流-直流升压电路的正极输入端连接至少一个光伏组串的正极，所述每个第二直流-直流升压电路的负极输入端连接所述至少一个光伏组串的负极。每个所述第二直流-直流升压电路用于将所连接的光伏组串提供的电压进行升压处理得到第一输入电压，并向所述直流-交流逆变电路提供所述第一输入电压。所述变换电路中的所述RSCC工作时，向所述直流-交流逆变电路提供第二输入电压。所述直流-交流逆变电路的输出端用于与电网连接，以将所述第一输入电压和所述第二输入电压转化为交流电压后提供给所述电网。
本申请实施例中，光伏系统中包括第一方面中的任意一种变换电路，变换电路中的RSCC工作时可以为光伏系统中的直流-交流逆变电路提供第二输入电压。变换电路中的控制电路可以在控制RSCC工作前，控制RSCC中的开关单元将第一电源提供的电能传输至RSCC中的输出滤波单元，避免RSCC处于工作状态的瞬间，电路中产生的电流对开关单元产生冲击，保障开关单元的工作性能，从而保障RSCC的工作性能，也可以保障光伏系统的工作性能。并且不需要增加额外的充电电路和控制开关等成本。
第三方面，本申请实施例提供一种变换电路预充电控制方法，应用于变换电路，所述变换电路包括第一电源、谐振开关电容变换器RSCC，所述RSCC包括开关单元和输出滤波单元。该方法可以由控制电路或者控制器执行，所述方法包括：控制电路控制所述开关单元将所述第一电源提供的电能传输至所述输出滤波单元。控制电路若确定所述输出滤波单元电压大于预设阈值，控制所述RSCC工作。
本申请实施例中，控制电路在控制RSCC工作前，控制RSCC中的开关单元将第一电源提供的电能传输至输出滤波单元中，提升输出滤波单元的电压。由于输出滤波单元中存储有电能，其电压不为零。控制电路在控制RSCC工作的瞬间，电路中形成的电流较弱，对RSCC中的开关单元影响较弱，可以保障开关单元的性能。控制电路通过控制RSCC中的开关单元，可使第一电源对输出滤波单元充电，提升输出滤波单元的电压，并且不需要 增加额外的充电电路，也可以保障RSCC的功率密度。
一种可能的设计中，所述RSCC还包括谐振单元；所述控制所述开关单元将所述第一电源提供的电能传输至所述输出滤波单元，包括：控制电路控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元。控制电路控制所述开关单元将所述谐振单元中的电能传输至所述输出滤波单元。
本申请实施例中，控制电路可以通过控制开关单元将第一电源提供的能量传输至谐振单元中，可使第一电源对谐振单元充电。然后在控制开关单元将谐振单元中电能传输至输出滤波单元，可使谐振单元对输出滤波单元充电。由于谐振单元和输出滤波单元中存储有电能，谐振单元电压不为零，输出滤波单元电压不为零，可以降低RSCC工作的瞬间，电路中形成的电流。
一种可能的设计中，所述RSCC还包括输入滤波单元，所述输入滤波单元包括第一子输入滤波单元和第二子输入滤波单元；所述方法还包括：控制电路控制所述开关单元将所述第一子输入滤波单元中的电能传输至所述输出滤波单元中。
本申请实施例中，控制电路还可以通过控制开关单元，使第一子输入滤波单元对输出滤波单元进行充电。控制电路可以将输入滤波单元中的子输入滤波单元作为能量中转单元，例如，第一子输入滤波单元对输出滤波单元进行充电，控制电路可以灵活地，精细地对输出滤波单元进行充电，保护变换电路中的元件。
一种可能的设计中，所述控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元，包括：控制电路控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能传输至所述谐振单元中；或者，控制电路控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能和提供给所述第二子输入滤波单元中的电能传输至所述谐振单元中。
本申请实施例中，控制电路在控制开关单元将第一电源提供的电能传输至谐振单元过程中，可以将输入滤波单元中的一个或多个子输入滤波单元做为能量中转单元。控制电路可以控制开关单元将一个或多个子输入滤波单元中的电能传输至谐振单元中。如，将第一子输入滤波单元中的能量传输至谐振单元中，可以降低对谐振单元充电过程中产生电流对开关单元的冲击。控制电路将输入滤波单元中的一个或多个子输入滤波单元做为能量中转单元，可以灵活地，精细地对谐振单元进行充电。
第四方面，本申请实施例提供一种变换电路预充电控制方法，应用于控制电路或者控制器。该方法可以包括以下步骤：控制开关单元将第一子输入滤波单元中的电能传输至谐振单元中，直至谐振单元电压大于第一预设阈值。根据第一预设方式，执行操作1和操作2。其中，操作1为控制开关单元将第一子输入滤波单元中的电能和第二子输入滤波单元中的电能传输至谐振单元中，操作2为控制开关单元将谐振单元中的电能和第一子输入滤波单元中的电能传输至输出滤波单元中。根据第二预设方式，执行操作3和操作4，其中，操作3为控制开关单元将第一子输入滤波单元中的电能传输至谐振单元中，操作3为控制开关单元将谐振单元中的电能传输至输出滤波单元中。
本申请实施例中，控制器可以在每个控制周期内控制开关单元将第一子输入滤波单元中的电能传输至谐振单元中，直至谐振单元电压大于第一预设阈值，可使谐振单元电压逐渐增大，并大于第一预设阈值。然后将第一子输入滤波单元和谐振单元作为能量中转单元，控制器通过根据第一预设方式，执行操作1和操作2，可实现将第一电源提供的电能传输 至输出滤波单元中，并且这个过程中，电路产生的电流较弱，保障开关单元的工作性能。控制器执行操作2后，输出滤波单元电压不为零。控制器通过根据第二预设方式，执行操作3和操作4，也可实现第一电源提供的电能传输至输出滤波单元，并且输出滤波单元被提供更多的电能。
一种可能的设计中，控制器在根据第二预设方式，执行操作3和操作4之前，控制器还可以控制开关单元将谐振单元中的电能和第一子输入滤波单元中的电能传输至输出滤波单元中，直至谐振单元电压小于或等于输出滤波单元电压与第一子输入滤波单元电压之和。
本申请实施例中，控制器根据第二预设方式，执行操作3和操作4之前，通过控制开关单元，使谐振单元和第一子输入滤波单元对输出滤波单元进行充电，使得谐振单元电压小于或等于输出滤波单元电压与第一子输入滤波单元电压之和，可以降低控制器后续充电过程中产生的电流尖峰，影响开关单元的工作性能。
一种可能的设计中，控制器在根据第二预设方式，执行操作3和操作4之后，若谐振单元的电压等于第一预设阈值，控制器可以根据第三预设方式，执行操作5和操作6，直至输出滤波单元电压大于第一电源提供的输入电压，其中，操作5为控制开关单元将第一子输入滤波单元中的电能和第二子输入滤波单元中的电能传输至谐振单元中，操作6为控制开关单元将谐振单元中的电能传输至输出滤波单元中。
本申请实施例中，控制器可以根据第三预设方式，执行操作5和操作6，使输出滤波单元的电压为输入电压。输出滤波单元的电压大于或等于输入电压，可以确定完成充电过程。控制器可以控制RSCC工作。
一种可能的设计中，控制器在根据第二预设方式，执行操作3和操作4之后，若谐振单元的电压不等于第一预设阈值，控制器可以控制开关单元将谐振单元中的电能传输至输出滤波单元中，直至谐振单元的电压等于第一预设阈值。或者控制开关单元将第一子输入滤波单元中的电能传输至输出滤波单元中，直至谐振单元的电压等于第一预设阈值。
第五方面，本申请实施例提供一种计算机可读存储介质，所述计算机可读存储介质包括计算机程序，当计算机程序在处理器上运行时，使得所述处理器执行本申请实施例第三方面及第三方面任一可能设计的技术方案或者第四方面及第四方面任一可能设计的技术方案。
第六方面，本申请实施例提供一种计算机程序产品，当所述计算机程序产品在电子设备上运行时，使得所述电子设备执行本申请实施例第三方面及第三方面任一可能设计的技术方案或者第四方面及第四方面任一可能设计的技术方案。
附图说明
图1为一种包括RSCC的变换电路的结构示意图；
图2为一种能够实现对RSCC预充电的变换电路的结构示意图；
图3为一种变换电路的结构示意图；
图4为一种充电过程中变换电路中的通路示意图；
图5为一种充电过程中变换电路中的通路示意图；
图6为一种变换电路的结构示意图；
图7为一种变换电路的结构示意图；
图8为一种充电过程中变换电路中的通路示意图；
图9为一种充电过程中变换电路中的通路示意图；
图10为一种充电过程中变换电路中的通路示意图；
图11为一种充电过程中变换电路中的通路示意图；
图12为一种充电过程中变换电路中的通路示意图；
图13为一种变换电路的结构示意图；
图14为一种变换电路预充电方法的示意流程图；
图15为一种变换电路预充电方法的示意流程图；
图16为一种充电过程中变换电路中的通路示意图；
图17为一种充电过程中变换电路中的通路示意图；
图18为一种充电过程中变换电路中的通路示意图；
图19为一种充电过程中变换电路中的通路示意图；
图20为一种电源的结构示意图；
图21为一种光伏系统的结构示意图；
图22为一种光伏系统的结构示意图。
具体实施方式
光伏发电系统、电动汽车、可再生能源系统对电力电子变换器需求不断增加。传统直流变换器普遍采用电感、变压器等磁性元件传递能量。因直流变换器工作在硬开关状态，使得传统直流变换器中开关损耗大，工作效率低，同时也影响使用直流变换器的系统的性能，如影响光伏发电系统的性能。
传统直流变换器中电感、变压器等磁性元件体积较大，使传统直流变换器的功率密度较低。区别于传统直流变换器，RSCC是一种新型直流变换器。RSCC中利用谐振电感和谐振电容的谐振单元传递能量。通常谐振单元的体积较小，因而RSCC具有较高的功率密度。谐振单元还可以使RSCC中的功率开关器件工作在软开关状态，提升RSCC的工作效率，也可以提升使用RSCC的系统的性能。
RSCC可以用于直流-直流变换电路中，可以对直流电压进行电压变换，如升压变换、降压变换、电压极性变换等，并输出变换后的直流电压。通常，RSCC包括多个开关管(开关)，多个电容，多个二极管和谐振单元。为RSCC提供输入电压后，通过控制多个开关的关断状态，实现输出目标电压。
图1中示出一种包括RSCC的变换电路拓扑结构。变换电路包括电源(输入电压为Vin)和RSCC。RSCC包括三个连接端点，分别为第一输入端点1和第二输入端点2。电源的一端与第一输入端点1连接，电源的另一端与第二输入端点2连接(图1中以电源的正极与第一输入端点1连接，电源的负极与第二输入端点2连接作为举例)。RSCC包括由串联连接的滤波电容C1、滤波电容C2和输出滤波电容C3形成的第一支路，由串联连接的开关T1、开关T2、开关T3和开关T4、二极管D3和二极管D4形成的第二支路，二极管D1，二极管D2以及谐振单元。谐振单元包括串联连接的谐振电容Cr和谐振电感Lr。
第一支路中，滤波电容C1的一端与第一输入端点1连接，另一端与滤波电容C2连接。输出滤波电容C3的一端与滤波电容C2连接，另一端与输出端点3连接。
第二支路中，开关T1的一端与第一输入端点1连接，另一端与开关T2连接。开关 T4的一端与开关T3连接，另一端与二极管D3的阴极连接。二极管D3的阳极与二极管D4的阴极连接，二极管D4的阳极与输出端点3连接。
滤波电容C1和滤波电容C2之间设置节点P1，开关T1和开关T2之间设置节点P2，开关T3和开关T4之间设置节点P3，开关T2和开关T3支架设置节点P4，二极管D3和二极管D4之间设置节点P5。二极管D1的阳极分别连接节点P1和二极管D2的阴极，二极管D1的阴极连接节点P2。二极管D2的阳极连接节点P3。谐振单元连接在节点P4和节点P5之间。
RSCC中开关T1、开关T2、开关T3和开关T4的控制端可以与控制电路连接。控制电路可以向开关发送驱动信号或者脉冲信号，控制开关处于导通状态或者处于断开状态。控制电路还可以根据预设控制时序以及各控制时序所对应的各开关的驱动信号，通过在不同控制时序上，向各开关发送与控制时序对应的驱动信号，使RSCC处于工作状态，实现将输入电压变换为目标输出电压。
由于在RSCC处于工作状态之前，输出滤波电容C3的电压几乎为零，谐振电容Cr的电压也几乎为零。在RSCC开始工作的瞬间，谐振电感Lr产生的电流会对开关等功率元件产生冲击，影响开关元件的性能，导致RSCC工作性能下降。
为避免在RSCC开始工作的瞬间，谐振电感Lr产生的电流对各开关的冲击，在控制电路控制RSCC处于工作状态之前可以对RSCC中的输出滤波电容，谐振电容等功率元件进行充电，使在RSCC开始工作的瞬间，减小谐振电感Lr产生的电流，从而降低电流对各开关的冲击。
如图2所示，将充电电路和开关控制单元接入RSCC中。充电电路可以对输出滤波电容C3充电，也可以对谐振电容Cr充电。开关控制单元可以控制充电电路分别对输出滤波电容C3和谐振电容Cr进行充电，使输出滤波电容C3和谐振电容Cr在RSCC处于工作状态之前的电压不为零。增加充电电路和开关控制电源，可以避免RSCC在处于工作状态时，谐振电感Lr形成的电流对各开关产生冲击。但是这种充电方式增加了变换电路的成本，也增加了变换电路的面积，导致变换电路的功率密度下降。
基于上述问题，本申请实施例提供一种对RSCC中的输出滤波电容充电的方法，可以应用于包括RSCC的变换电路，以不增加额外成本，并避免在RSCC处于工作状态瞬间电路中产生电流对开关造成冲击，保障RSCC的工作性能。
如图3所示，本申请实施例提供的变换电路可以包括RSCC 31、第一电源32和控制电路33。RSCC 31可以包括开关单元301，输出滤波单元304，第一输入端S1，第二输入端S2和输出端S3。开关单元301可以连接在第一输入端S1和第二输入端S2之间。控制电路33与开关单元301连接，可以对开关单元301进行控制。
输出滤波单元304可以连接在第二输入端S2和输出端S3之间。输出滤波单元304可以包括至少一个电容，例如输出滤波电容。
第一电源32的两极分别与RSCC 31的第一输入端S1和第二输入端S2连接。例如，第一电源32的正极与第一输入端S1连接，第一电源32的负极与第二输入端S2连接。第一电源32可以为RSCC 31提供电能。
控制电路33可以用于本申请提供的对RSCC中的输出滤波充电方法。控制电路33可以在控制RSCC工作前，控制开关单元301将第一电源提供的电能传输至输出滤波单元304。本申请实施例中，控制电路33控制RSCC 31工作，可以指控制RSCC 31处于工作状态。 例如，控制RSCC 31将第一电源32提供的输入电压，转换为目标电压，或者称目标输出电压。目标电压可以经由RSCC 31的第二输入端S2和输出端S3输出提供给负载，例如，逆变电路等。RSCC 31可以应用在升压变换、降压变换、极性变换等场景中。在升压变换场景中，目标电压的数值可以大于输入电压。在降压变换场景中，目标电压的数值可以小于输入电压。在极性变换场景中，目标电压可以与输入电压绝对值相等，极性相反。RSCC31也可以应用于其它电压变换场景中，此处不再一一列举。
控制电路33可以实施为控制器。控制电路33也可以包括多个控制单元，不同控制单元可以用于控制RSCC处于不同的运行状态。例如，第一控制单元用于控制RSCC 31处于工作状态，第二控制单元用于在RSCC 31工作前控制开关单元301将第一电源32提供的电能传输至输出滤波单元304中。控制电路33在RSCC 31工作前控制开关单元301将第一电源32提供的电能传输至输出滤波单元304中的过程，可以视为控制RSCC 31处于预充电状态。
本申请实施例中，控制电路33可以控制开关单元301将第一电源32提供的电能传输至输出滤波单元304，实现第一电源32对RSCC 31中的输出滤波单元304充电。控制电路33可以向控制开关单元301发送(或提供)控制信号或者驱动信号。开关单元301可以在接收控制信号或者驱动信号时，将第一电源32提供的电能传输至输出滤波单元304。开关单元301也可以在未接收到控制信号或者驱动信号时，不将第一电源32提供的电能传输至输出滤波单元304。
防止充电时电路中的电流过大，会影响开关单元301中开关的性能，控制电路33还可以控制开关单元301将第一电源32提供的电能传输至输出滤波单元304的持续时长。例如，控制电路33在预设时长内持续向开关单元301发送控制信号或者驱动信号。开关单元301在预设时长内持续地将第一电源32提供的电能传输至输出滤波单元304中。其中，预设时长可以小于一个控制周期。
输出滤波单元304被充电的时长不同，输出滤波单元304电压增加情况也不同。换句话说，控制电路33向开关单元301发送控制信号或者驱动信号的持续时长不同，输出滤波单元两端增加电压情况也不同。例如，控制电路可以在第一时长内持续向开关单元301发送控制信号或者驱动信号。控制电路也可以在第二时长内持续向开关单元301发送控制信号或者驱动信号。若第一时长和第二时长是不同的数值，输出滤波单元304被充电第一时长后的电压增加量，与输出滤波单元304被充电第二时长后的电压增加量不同。
一种可能的实施方式中，控制电路33可以多次控制开关单元301将第一电源32的电能传输至输出滤波单元304中，可使输出滤波单元304被多次充电。控制电路33每次控制开关单元301将第一电源32的电能传输至输出滤波单元304中的持续时长可以相同，也可以不同。换句话说，控制电路33可以在每个控制周期中的相同时段或者不同时段内，持续向开关单元301发送控制信号或者驱动信号，使开关单元301将第一电源32的电能传输至输出滤波单元304中。
输出滤波单元304被充电后，电压不为零，可以降低RSCC 31处于工作状态的瞬间产生的电流对开关单元301产生冲击。可见，本申请实施例提供对RSCC中的输出滤波电容充电的方法，可以保障变换电路中功率元件的性能，以及变换电路的功率密度，并且还不需要增加变换电路的成本。
RSCC 31中还可以包括谐振单元302和钳位单元303。所述钳位单元303与所述输出 滤波单元304并联。钳位单元303可以用于限制第二输入端S2的电压不发生改变。
所述开关单元301与所述谐振单元302的一端连接，所述谐振单元302的另一端与所述钳位单元303连接。谐振单元302可以包括串联的谐振电容和谐振电感。谐振单元302可以用于传递能量，使开关单元301中的开关器件工作在软开关状态。
RSCC 31中也可以包括输入滤波单元305。输入滤波单元305与开关单元301并联连接，可以用于在RSCC 31处于工作状态时，对第一电源32提供的输入电压进行稳压。输入滤波单元305可以包括至少一个串联的电容。输入滤波单元305连接在第一电源32的两极之间，第一电源32可以直接为输入滤波单元305提供电能，输入滤波单元305也可以用于存储第一电源32提供的电能。
本申请实施例中，开关单元301的第一端301a分别连接RSCC 31的第一输入端S1和输入滤波单元305的输入端305a。开关单元301的第二端301b连接第二输入端S2。开关单元301的第三端301c与谐振单元302的第一端302a连接。开关单元301的第四端301d可以与控制电路33连接。
谐振单元302的第二端302b与钳位单元303的第一输入端303a连接。钳位单元303的第二输入端303b与RSCC 31的输出端S3连接。钳位单元303的输出端303c与RSCC 31的第二输入端S2连接。
输入滤波单元305的输入端305a分别与第一输入端S1和开关单元301的第一端301a连接。输入滤波单元305的输出端305b分别与第二输入端S2和输出滤波单元304的输入端304a连接。输出滤波单元304的输入端304a分别与输入滤波单元305的输出端305b和第二输入端S2连接。输出滤波单元304的输出端304b与RSCC 31的输出端S3连接。
本申请实施例中，谐振单元302还可以用于中转电能，或者说谐振单元302作为能量中转单元(能量中继单元、能量中继组件或者能量中继模组)。控制电路33控制RSCC 31中的开关单元301将所述第一电源32提供的电能传输至所述输出滤波单元304时，可以控制所述开关单元301将所述第一电源32提供的电能传输至所述谐振单元302，可以实现第一电源32对谐振单元302充电。然后控制所述开关单元301将所述谐振单元302中的电能传输至所述输出滤波单元304，可以实现谐振单元302对输出滤波单元304充电。应理解的是，谐振单元302可以作为能量中转媒介，接受第一电源32的充电。谐振单元302也可以在被充电后将电能提供给输出滤波单元304，对输出滤波单元304充电。
输出滤波单元304因被充电，其电压不为零。谐振单元302在对输出滤波单元304充电后，谐振单元302中的电能减少，电压下降。虽然谐振单元302电压下降，但其电压值也大于零。RSCC 31处于工作状态的瞬间，谐振单元302中的谐振电感产生较弱的电流，降低对开关单元301的冲击。可见，本申请实施例提供变换电路中，控制电路33通过控制开关单元301，使RSCC 31中的输出滤波单元304和谐振单元302被充电，可以保障变换电路中开关元件的性能，以及变换电路的功率密度，并且利用变换电路中的元件，对RSCC中的谐振电容和输出滤波电容充电，还可以不增加额外的成本。
开关单元301可以包括多个串联连接的开关。本申请实施例中，控制电路33控制开关单元301将第一电源32提供的电能传输至谐振单元302时，控制电路33可以控制开关单元301中的各开关的导断状态，使第一电源32、开关单元301、谐振单元302、钳位单元303形成第一通路，开关单元301和第二输入端S2之间断路，钳位单元303的第二输入端303b与输出端S3之间断路。谐振单元302的第一端302a经由开关单元301与第一 电源32的一极连通，谐振单元302的第二端302b经由钳位单元303与第一电源32的另一极连通，第一电源32可以对谐振单元302进行充电。
在第一电源32对谐振单元302充电过程中，钳位单元303的第二输入端303b和输出滤波单元304的输出端304b之间断路，第一通路中的电流没有流入输出滤波单元304，可使得输出滤波单元304两端断路。图4中示出第一电源32对谐振单元302充电过程中，RSCC 31中的通路和断路情况，其中，粗线示出RSCC 31中的第一通路，虚线示出RSCC31中断路情况。
一种可能的实施方式中，控制电路33可以多次控制开关单元301将第一电源32提供的电能传输至谐振单元302，使谐振单元302被多次充电。谐振单元302对输出滤波单元304充电后，电压降低。为进一步减小RSCC 31处于工作状态瞬间谐振单元302中的电感产生的电流。控制电路33可以再次控制开关单元301将第一电源32提供的电能传输至谐振单元302中，使第一电源32再次对谐振单元302充电。
谐振电源302每次被充电的时长可以相同，也可以不同。控制电路33可以通过控制开关单元301在预设时长内持续地将第一电源32提供的电能传输至谐振单元302的方式，实现控制谐振单元302被充电的时长为所述预设时长。预设时长可以小于一个控制周期对应的时长。例如，一个控制周期对应的时长可以是55微秒，预设时长可以是1.8％*55微秒，预设时长也可以是2％*55微秒。
控制电路33控制开关单元301将谐振单元302中的电能传输至输出滤波单元304时，控制电路33可以控制开关单元301中的各开关的导断状态，使开关单元301、谐振单元302、钳位单元303、输出滤波单元304形成第二通路，开关单元301的第二端301b与第二输入端S2之间导通，钳位单元303的输出端303c与第二输入端S2之间断路。谐振单元302中存储有第一电源32提供的电能，由于输出滤波单元304的电压几乎为零，在形成第二通路后，谐振单元302进行放电，实现谐振单元302对输出滤波单元304充电。图5中示出谐振单元302对输出滤波单元304充电过程中，RSCC31中的通路和断路情况，其中，粗线示出RSCC 31中第二通路，虚线示出RSCC 31中断路情况。
输出滤波单元304也可以被多次充电。控制电路33可以多次控制开关单元301将谐振单元302中的电能传输至输出滤波单元304。控制电路33可以在谐振单元302被再次充电后，控制开关单元301将谐振单元302中的电能传输至输出滤波单元304。输出滤波单元304每次被充电的时长可以相同，也可以不同。
一个示例中，控制电路33可以在谐振单元302对输出滤波单元304充电后，判断谐振单元302电压是否在第一电压范围内。若谐振单元302电压小于第一电压范围内的最小值，控制电路33可以控制开关单元301将第一电源32提供的电能传输至谐振单元302中。
本申请实施例中，第一电压范围也可以根据第一电源32提供的电压确定。第一电压范围内的数值可以是接近第一电源32输出电压Vin的一半电压值0.5Vin的任意数值。例如，第一电压范围中的最小值可以为0.48Vin，第一电压范围可以为[0.48Vin，Vin]。第一电压范围也可以由不连续的数值，如{0.48Vin，0.485Vin，0.5Vin，0.51Vin}。本申请实施例中，接近第一电源32输出电压Vin的一半电压值0.5Vin的数值范围可以根据RSCC中的元件参数进行配置。
另一个示例中，控制电路33也可以在谐振单元302对输出滤波单元304充电后，判断输出滤波单元304电压是否大于或等于预设电压值。若输出滤波单元303两端的电压大 于或等于预设电压值，控制电路33可以确定完成对RSCC 31中的输出滤波单元304的充电。本申请实施例中，预设电压值可以是输入电压Vin。
控制电路33还可以在确定完成对输出滤波单元304充电后，控制RSCC 31处于工作状态，输出目标电压。控制电路33也可以在确定完成对输出滤波单元304充电后，确定谐振单元302电压是否在第一电压范围内。若谐振单元302电压小于第一电压范围内的最小值，控制电路33可以一次或者多次控制开关单元301将第一电源32提供的电能传输至谐振单元302中，使谐振单元302电压大于或等于第一电压范围内的最小值。控制电路33确定输出滤波单元304电压大于或等于预设电压值，谐振单元302电压大于或等于第一电压范围内的最小值，可以确定完成对输出滤波单元304和谐振单元302充电。然后控制RSCC 31处于工作状态，输出目标电压。
一种可能的实施方式中，开关单元301可以包括至少两个开关，至少两个开关中的两个开关串联连接，并且这两个开关之间的连接线上设置有第一节点，第一节点可作为开关单元301的第三端301c。本申请实施例中的开关可以是功率开关管，例如场效应晶体管。本申请实施例的附图中以开关为带有寄生二极管的场效应晶体管作为举例，并不作为本申请实施例中开关的具体形态进行限定。
一个示例中，开关单元301可以包括串联连接的两个开关。如图6所示，开关单元301包括开关T5和开关T6。开关T5不与开关T6连接的一端可作为开关单元301的第一端301a。开关T6不与开关T5连接的一端可作为开关单元301的第二端301b。开关单元中第一节点M1设置在开关T6与开关T5之间的连接线上，可以作为开关单元301的第三端301c，第一节点M1与谐振单元302的第一端302a连接。
本申请实施例中，钳位单元303可以包括两个串联连接的二极管，两个二极管之间的连接线上设置有第二节点M2，作为钳位单元303的第一输入端303a。第二节点M2分别连接一个二极管的阳极和另一个二极管的阴极。两个二极管中，阴极与第二节点M2连接的二极管可为第一二极管，第一二极管的阳极可作为钳位单元303的第二输入端303b，与RSCC 31的输出端S3连接。另一个二极管为第二二极管，第二二极管的阳极连接第二节点M2，第二二极管的阴极可作为钳位单元303的输出端303c，与RSCC 31的第二输入端S2连接。
如图6所示，钳位单元303包括串联连接的二极管D5和二极管D6，二极管D5的阳极连接二极管D6的阴极，二极管D5的阴极为钳位单元303的输出端303c，二极管D5的阳极可作为钳位单元303的第一输入端303a。二极管D6的阳极为钳位单元303的第二输出端303b。
谐振单元302连接在第一节点M1和第二节点M2之间。由于二极管具有正向导通的特性，谐振单元302输出的电流流经第二节点时M2，二极管D6的阴极连接第二节点M2，电流无法流入二极管D6，二极管D6为截止状态，可使钳位单元303的第二输入端303b与RSCC 31的输出端S3之间断路。
一个示例中，钳位单元303也可以包括一个二极管和开关，二极管和开关串联连接。第二节点M2设置在二极管和开关之间的连接线上，作为钳位单元303的第一输入端303a。开关不与第二节点M2连接的一端可作为钳位单元303的第二输入端303b。二极管的阴极可作为钳位单元303的输出端303c。控制电路33可以控制该开关的通断状态。控制电路33可以控制钳位单元303中的开关处于断开状态，可使钳位单元303的第二输入端303b 与RSCC 31的输出端S3之间断路。控制电路33也可以控制钳位单元303中的开关处于导通状态，可使钳位单元303的第二输入端303b与RSCC 31的输出端S3之间导通。
应理解的是，钳位单元303还可以由其它元件组成，以能够实现本申请实施例中RSCC31中钳位单元303的作用或功能。本发明实施例对此不作过多限定。
谐振单元302中的谐振电感和谐振电容可以串联连接。如图6所示，谐振单元302可以包括串联连接的电容C6和电感L1，电容C6不连接电感L1的一端可作为谐振单元302的第一端302a，电感L1不与电容C6连接的一端作为谐振单元302的第二端302b。谐振单元302的第二端302b可以与二极管D5和二极管D6之间的第二节点M2连接。谐振单元302的第一端302a可以与开关T5和开关T6之间的第一节点M1连接。
输入滤波单元305可以包括电容C4。输出滤波单元304可以包括电容C5。控制电路33可与开关单元301中的至少两个开关中的每个开关连接，控制电路33可以控制每个开关的通断状态。控制电路33可以通过控制开关单元301的至少两个开关的通断状态，实现使第一电源32、开关单元301、谐振单元302、钳位单元303形成第一通路，开关单元301和第二输入端S2之间断路，钳位单元303与RSCC 31的输出端S3之间断路，实现控制第一电源32对谐振单元302和输入滤波单元305充电。
例如，开关单元301可以包括两个开关，开关T5和开关T6。控制电路33分别与开关T5和开关T6连接。控制电路33可以控制开关单元301中的开关T5导通、开关T6断开，第一电源32的一极经由开关单元301中的开关T5与谐振单元302之间导通。谐振单元302中的谐振电容C6的电压不同，使谐振电感L1产生的感应电流输入钳位单元303中，然后经由钳位单元303中的二极管D5，流入第一电源32的另一极。使谐振单元302的第二端302b经由钳位单元303中的二极管D5与第一电源的另一极之间导通，使第一电源32、开关单元301、谐振单元302、钳位单元303形成第一通路。第一电源32提供的电能经由开关单元301中的开关T5传输至谐振单元302中，可实现第一单元32对谐振单元302中的谐振电容C6充电。第一电源32的两极分别连接输入滤波单元305中的电容C4的两端，电容C4可存储第一电源32提供的电能。
本申请实施例中，控制电路33还可以控制开关T5断开，控制开关T6导通，谐振单元302中的电容C6经由开关单元301中开关T6与输入滤波单元305的输入端305a连通。输出滤波单元304的输出端304b经由钳位单元303中的二极管D6与谐振单元302中的电感L1连通，使谐振单元302、开关单元301、输出滤波单元304和钳位单元303之间形成第二通路。谐振单元302中的谐振电容C6中的电能可以经由开关单元301中的开关T6传输至输出滤波单元304中，可实现谐振单元302对输出滤波单元304充电。
本申请实施例中，在对输出滤波单元304充电过程中，控制电路33可以多次将谐振单元302能量传输的中间媒介。控制电路33可以在多个控制周期中，通过对开关单元301中的开关T5和开关T6的通断状态进行控制，实现控制开关单元301将第一电源32提供的电能传输至输出滤波单元305。
在多个控制周期中，控制电路33可以根据预先设置各控制周期中的控制操作，使开关单元301将第一电源32提供的电能传输至输出滤波单元305。
在第一控制周期中，控制电路33可以执行向开关T5持续发送控制信号或者驱动信号的控制操作。例如，控制电路33可以在第一控制周期中，向开关T5提供脉冲宽度为预设时长的脉冲信号。开关T5接收到脉冲信号后，处于导通状态直至脉冲结束。开关T6在未 接收到脉冲信号，处于断路状态。第一控制周期的时长可以是55微秒，预设时长可以是1.8％*55微秒，预设时长也可以是2％*55微秒。控制电路33可以在第一控制周期中的前半个周期内执行向开关T5持续发送控制信号或者驱动信号的控制操作。控制电路33也可以在第一控制周期中的后半个周期内执行向开关T5持续发送控制信号或者驱动信号的控制操作。开关T5处于导通状态，开关T6处于断开状态，第一电源32提供的电能通过开关T5传输至谐振单元302中。
在第二控制周期中，控制电路33可以执行向开关T6持续发送控制信号或者驱动信号的控制操作。例如，控制电路33可以在第二控制周期中，向开关T6提供脉冲宽度为预设时长的脉冲信号。开关T6接收到脉冲信号后，处于导通状态直至脉冲结束。开关T5在未接收到脉冲信号，处于断路状态。第二控制周期的时长可以是55微秒，预设时长可以是1.8％*55微秒，预设时长也可以是2％*55微秒。控制电路33可以在第二控制周期中的前半个周期内执行向开关T6持续发送控制信号或者驱动信号的控制操作。控制电路33也可以在第一控制周期中的后半个周期内执行向开关T6持续发送控制信号或者驱动信号的控制操作。开关T6处于导通状态，开关T5处于断开状态，谐振单元302中的电能通过开关T6传输至输出滤波单元304中。
多个控制周期中可以包括至少一个第一控制周期，以及至少一个第二控制周期。控制电路33在不同控制周期内执行的控制操作不同。控制电路33通过在不同周期内执行不同的控制操作，可使第一电源32对谐振单元302充电后以及谐振单元302对输出滤波单元304充电，这两个充电过程交替进行。
在实际应用场景中，控制电路33可以通过与元件并联连接的调理电路确定元件两端的电压。例如通过与输出滤波单元304中的电容C5并联的调理电路确定电容C5的电压等。控制电路33也可以通过与元件并联的模拟数字采样电路，确定元件两端的电压，例如通过与谐振单元302中的电容并联的模拟数字采样电路，确定电容C6的电压等。
输入滤波单元305也可以存储第一电源32提供的电能。在输入滤波单元305可以包括多个子输入滤波单元的场景中。控制电路33也可以将输入滤波单元305中的子输入滤波单元作为能量中转媒介。
控制电路33可以控制开关单元301将子输入滤波单元中的电能传输至谐振单元302中，实现输入滤波单元305中的子输入滤波单元对谐振单元302充电。子输入滤波单元对谐振单元302充电电压小于第一电源32提供的输入电压，充电时产生的电流尖峰较小，可以减轻电路中的开关受到的电流冲击。
下面以输入滤波单元305包括两个子输入滤波单元作为举例进行说明。如图7所示，输入滤波单元305中的两个子输入滤波单元，分别记为第一子输入滤波单元305N1和第二子输入滤波单元305N2。第一子输入滤波单元305N1和第二子输入滤波单元305N2串联连接。第二子输入滤波单元305N2的输入端连接RSCC 31的第一输入端S1，第二子输入滤波单元305N2的输出端连接第一子输入滤波单元305N1的输入端。第一子输入滤波单元305N1的输出端分别与第二输入端S2和输出滤波单元304的输入端304a连接。本申请实施例中，第一子输入滤波单元305N1可以包括至少一个串联的电容。第二子输入滤波单元305N2可以包括至少一个串联的电容。
开关单元301的第一端301a分别连接RSCC 31的第一输入端S1连接和第二子输入滤波单元305N2的输入端。开关单元301的第二端301b连接第二输入端S2。开关单元301 的第三端301c与谐振单元302的第一端302a连接。开关单元301的第四端301d可以与控制电路33连接。控制电路33可以对开关单元301进行控制。开关单元301的第五端301e分别与第二子输入滤波单元305N2的输出端，以及第一子输入滤波单元305N1的输入端连接。换句话说，开关单元301的第五端301e连接在第一子输入滤波单元305N1和第二子输入滤波单元305N2之间的。
谐振单元302的第一端302a与开关单元301的第三端301c连接，谐振单元302的第二端302b与钳位单元303的第一输入端303a连接。钳位单元303的第一输入端303a与谐振单元302的第二端302b连接。钳位单元303的第二输入端303b与RSCC 31的输出端S3连接。钳位单元303的输出端303c与RSCC 31的第二输入端S2连接。
输出滤波单元304的输入端304a分别与输入滤波单元305的输出端305b和第二输入端S2连接。输出滤波单元304的输出端304b与RSCC 31的输出端S3连接。输出滤波单元304可以包括至少一个电容。第一电源32的两极分别与RSCC 31的第一输入端S1和第二输入端S2连接。
控制电路33控制所述开关单元301将所述第一电源32提供的电能传输至所述谐振单元302之前，控制电路33可以控制开关单元301与第一输入端S1之间断路，以及与第二输入端S2之间断路，使开关单元301停止传输电能。第一电源32与第一子输入滤波单元305N1、第二子输入滤波单元305N2之间形成通路，第一电源32可以对第一子输入滤波单元305N1、第二子输入滤波单元305N2进行充电。示例性的，控制电路33可以控制开关单元301与第二子输入滤波单元305N2之间断路、开关单元301与RSCC 31的第二输入端S2之间断路，也即控制电路33控制RSCC 31中的开关单元301、谐振单元302、钳位单元303以及输出滤波单元304之间断路，使第一子输入滤波单元305N1和第二子输入滤波单元305N2串联在第一电源32两极之间，从而使第一电源32对第一子输入滤波单元305N1和第二子输入滤波单元305N2充电。图8中示出第一子输入滤波单元305N1和第二子输入滤波单元305N2充电过程中，变换电路中通路和断路情况，其中，粗线示出导通部分，虚线示出断路部分。
控制电路33控制所述开关单元301将所述第一电源32提供的电能传输至所述谐振单元302时，控制电路33可以控制开关单元301将第一子输入滤波单元305N1和第二子输入滤波单元305N2中的任意一个子输入滤波单元中的电能传输至谐振单元中。例如，控制电路33控制开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302中，可使第一子输入滤波单元305N1对谐振单元302进行充电。第一子输入滤波单元305N1中的电能少于第一电源32所提供的电能，由第一子输入滤波单元305N1对谐振单元302充电，可以降低电路中产生的电流。
控制电路33控制开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302时，控制电路33可以控制开关单元301中的各开关的导断状态，使第一子输入滤波单元305N1、开关单元301、谐振单元302、钳位单元303之间形成第四通路，开关单元301和第一输入端S1之间断路，开关单元301与RSCC 31的第二输入端S2之间断路，钳位单元303与输出滤波单元304之间断路，第一子输入滤波单元305N1可以通过第四通路可以对谐振单元302进行充电。图9中示出第一子输入滤波单元305N1对谐振单元302充电过程中，RSCC 31中通路和断路情况，其中，粗线示出第四通路，虚线示出断路部分。本申请实施例中，通过多个输入滤波单元中的一部分输入滤波单元对谐振单元302进行充 电，可以降低充电过程中电流对RSCC 31中元件的冲击，进一步对变换电路中元件进行保护。
控制电路33控制所述开关单元301将所述第一电源32提供的电能传输至所述谐振单元302时，控制电路33还可以控制开关单元301将第一子输入滤波单元305N1和第二子输入滤波单元305N2中的电能传输至谐振单元302中进行充电。控制电路33可以控制开关单元301中的各开关的导断状态，使第一子输入滤波单元305N1、第二子输入滤波单元305N2、开关单元301、谐振单元302、钳位单元303之间形成第五通路，控制开关单元301与RSCC 31的第二输入端S2之间断路，钳位单元303与输出滤波单元304之间断路，第一子输入滤波单元305N1和第二子输入滤波单元305N2可以通过第五通路可以对谐振单元302进行充电。图10中示出在第一子输入滤波单元305N1和第二子输入滤波单元305N2一同对谐振单元302充电过程中，RSCC 31中通路和断路情况，其中，粗线示出第五通路，虚线示出断路部分。
控制电路33控制所述开关单元301将所述第一电源32提供的电能传输至所述谐振单元302时，控制电路33还可以控制开关单元301将第一电源32提供的电能传输至谐振单元302中。第一电源32、开关单元301、谐振单元302、钳位单元303之间形成通路，所述开关单元301和所述第二输入端S2之间断路，所述钳位单元303与所述输出端S3之间断路。
控制电路33控制开关单元301将谐振单元302中的电能传输至输出滤波单元304中时，控制电路33可以控制开关单元301将谐振单元302和第一子输入滤波单元305N1中的电能传输至输出滤波单元304中，可实现谐振单元302和第一子输入滤波单元305N1对输出滤波单元304充电。控制电路33可以控制开关单元301中的各开关的导断状态，使第一子输入滤波单元305N1、开关单元301、谐振单元302、钳位单元303、输出滤波单元304形成第六通路，开关单元301的第二端301b与RSCC 31的第二输入端S2之间断路，开关单元301的第一端301a与RSCC 31的第一输入端S1之间断路。谐振单元302和第一子输入滤波单元305N1通过第六通路对输出滤波单元304充电。图11中示出谐振单元302和第一子输入滤波单元305N1对输出滤波单元304充电过程中，RSCC 31中通路和断路情况，其中，粗线示出第六通路，虚线示出断路部分。
控制电路33控制开关单元301将谐振单元302中的电能传输至输出滤波单元304中时，控制电路33可以控制开关单元301将谐振单元302中的电能传输至输出滤波单元304中，可实现谐振单元302对输出滤波单元304充电。控制电路33可以控制开关单元301中的各开关的导断状态，使谐振单元302、开关单元301、输出滤波单元304和钳位单元303形成第七通路，开关单元301的第一端301a与RSCC 31的第一输入端S1之间断路，开关单元301的第二端301b与RSCC 31的第二输入端S2之间断路，开关单元301的第五端301e与第一子输入滤波单元305N1之间断路。图12中示出谐振单元302对输出滤波单元304充电过程中，RSCC 31中通路和断路情况，其中，粗线示出第七通路，虚线示出断路部分。
如图13所示，本申请实施例中开关单元301还可以包括开关T7、开关T8、二极管D7和二极管D8。开关T7的一端分别与开关T5和二极管D8的阴极连接，开关T7不连接开关T5的一端可作为开关单元301的第一端301a，与RSCC 31的第一输入端S1连接。开关T8的一端分别与开关T6和二极管D7的阳极连接，开关T8不连接开关T6的一端可 作为开关单元301的第二端301b，与RSCC 31的第二输入端S2连接。开关T5与开关T6之间的第一节点M1可为开关单元301的第三端301c。二极管D8的阳极与二极管D7的阴极连接。开关单元301中的二极管D7的阴极与二极管D8的阳极之间的连接点可作为开关单元301的第五端303e。
控制电路33可以通过控制开关单元301中的四个开关全部处于断开状态，也即控制电路33控制开关T7，开关T5，开关T6，开关T8均处于断开状态，实现控制开关单元301停止传输电能，使得第一电源32可以对第一子输入滤波单元305N1和第二子输入滤波单元305N2进行充电。
控制电路33可以通过控制开关T7，开关T6，开关T8处于断开状态，以及开关T5处于导通状态，实现控制开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302中，可使第一子输入滤波单元305N1对谐振单元302充电。
控制电路33也可以通过开关T7和开关T5处于导通状态，控制开关T6和开关T8处于断开状态，实现控制开关单元301将第一子输入滤波单元305N1和第二子输入滤波单元305N2中的电能传输至谐振单元302中，可使第一子输入滤波单元305N1和第二子输入滤波单元305N2一同对谐振单元302进行充电。
控制电路33可以通过控制开关T7、开关T5和开关T8处于断开状态，控制开关T6处于导通状态，实现开关单元301将谐振单元302和第一子输入滤波单元305N1中的电能传输至输出滤波单元304，可使谐振单元302和第一子输入滤波单元305N1一同对输出滤波单元304充电。
控制电路33也可以通过控制开关T7和开关T5处于断开状态，控制开关T6和开关T8处于导通状态，实现开关单元301将谐振单元302中的电能传输至输出滤波单元304，可使谐振单元302对输出滤波单元304充电。
根据前述实施例，控制电路33通过控制开关单元301中各开关的导通状态，可以改变开关单元301中的第一节点M1处的电压和钳位单元303中第二节点M2处的电压。
例如，开关T7和开关T5处于导通状态，开关T6和开关T8处于断开状态，第一节点M1处的电压值等于第一输入端S1的电压值，第二节点M2处的电压值等于第二输入端S2的电压值。在变换电路中，可以由第一电源32对谐振单元302充电，或者由第一子输入滤波单元305N1和第二子输入滤波单元305N2一同对谐振单元302充电。
开关T6处于导通状态，开关T5、开关T7和开关T8处于断开状态，第一节点M1处的电压值等于第一子输入滤波单元305N1与第二子输入滤波单元305N1之间节点的电压，第二节点M2处的电压值等于第二输入端S2的电压值。在变换电路中，可以由第一子输入滤波单元305N1对谐振单元302充电。
这两种情形下，谐振单元302都处于被充电状态，谐振单元302中传输电能的开关不同，第一节点M1处的电压来源有多种可能。在输出滤波单元中包括多个子输出滤波单元数量，谐振单元302被充电的方式也更多。因而控制电路33也具有更多控制开关单元301将第一电源32提供的电能传输至谐振单元302的控制方式。
再例如，开关T7、开关T5和开关T8处于断开状态，控制开关T6处于导通状态，第一节点M1处的电压值等于第一子输入滤波单元305N1与第二子输入滤波单元305N1之间节点的电压，第二节点M2处的电压值等于输出滤波单元304的输出端304b的电压值。在变换电路中，谐振单元302和第一子输入滤波单元305N1一同对输出滤波单元304充电。
开关T7和开关T5处于断开状态，控制开关T6和开关T8处于导通状态，第一节点M1处的电压值等于第二输入端S2的电压值，第二节点M2处的电压值等于输出滤波单元304的输出端304b的电压值。在变换电路中，谐振单元302对输出滤波单元304充电。
类似地，这两种情形下，输出滤波单元304都处于被充电状态，谐振单元302中传输谐振单元302中所提供的电能的开关不同，谐振单元302中的电能经第一节点M1传输给其它单元也有多种可能，例如第一子输入滤波单元305N1，输出滤波单元304。在输出滤波单元中包括多个子输出滤波单元数量，输出滤波单元304被充电的方式也更多。因而控制电路33也具有更多控制开关单元301将谐振单元302中的电能传输至输出滤波单元304的控制方式。
应理解的是，在实际应用场景中，对RSCC 31中输出滤波单元304充电时，为避免充电时电路中可能产生的对开关单元301具有冲击的电流。控制电路33可以利用前述多种控制操作，精细化地控制输出滤波单元304被充电的过程。
例如，控制电路33先控制开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302中，由第一子输入滤波单元305N1对谐振单元302充电，第一子输入滤波单元305N1中的电能少于第一电源32所提供的电能，对谐振单元302充电过程中产生的电流较小。
相比于谐振单元302中没有电能时，第一电源32直接对谐振单元302充电过程中的电流。谐振单元302被第一子输入滤波单元305N1充电后，谐振单元302中存储有一定的电能，第一电源32对谐振单元302充电过程中的电流更小，避免对开关单元301产生冲击。
一个控制周期内，控制电路33可以执行前述任意一种使谐振单元302被充电的控制操作，也可以执行前述任意一种使输出滤波单元304被充电的控制操作。其中，执行谐振单元302被充电的控制操作的时段与执行输出滤波单元304被充电的控制操作的时段不重叠。
一个示例中，控制电路33可以在第一控制周期中的前半个周期，控制开关单元301将第一子输入滤波单元305N1和第二子输入滤波单元305N2中的电能传输至谐振单元302中。控制电路33可以在第一控制周期中的后半个周期，控制谐振单元302控制开关单元301将谐振单元302中的电能传输至输出滤波单元304中。或者控制电路33可以在一个控制周期中的后半个周期，控制开关单元301将第一子输入滤波单元305中的电能和谐振单元302中的电能传输至输出滤波单元304中。
另一个示例中，控制电路33可以在第二控制周期中的前半个周期，控制开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302中。控制电路33可以在第二控制周期中的后半个周期，控制开关单元301将谐振单元302中的电能传输至输出滤波单元304中。或者控制电路33可以在第二控制周期中的后半个周期，控制开关单元301将第一子输入滤波单元305中的电能和谐振单元302中的电能一同传输至输出滤波单元304中。
一个控制周期内，控制电路33也可以多次执行前述任意一种使谐振单元302被充电的控制操作，以及多次执行前述任意一种使输出滤波单元304被充电的控制操作。其中，执行谐振单元302被充电的控制操作的时段与执行输出滤波单元304被充电的控制操作的时段不重叠。控制电路33所执行的相邻两次谐振单元302被充电的控制操作之间，控制 电路33执行一次使输出滤波单元304被充电的控制操作。
一个示例中，控制电路33可以在第三控制周期中的前半个周期的第一时段，控制开关单元301将第一子输入滤波单元305N1和第二子输入滤波单元305N2中的电能传输至谐振单元302中。或者，控制开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302中。控制电路33可以在第一控制周期中的前半个周期的第二时段，控制谐振单元302控制开关单元301将谐振单元302中的电能传输至输出滤波单元304中。或者控制开关单元301将第一子输入滤波单元305中的电能和谐振单元302中的电能传输至输出滤波单元304中。
控制电路33可以在第三控制周期中的后半个周期的第三时段，控制开关单元301将第一子输入滤波单元305N1和第二子输入滤波单元305N2中的电能传输至谐振单元302中。或者，控制开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302中。控制电路33可以在第一控制周期中的后半个周期的第四时段，控制谐振单元302控制开关单元301将谐振单元302中的电能传输至输出滤波单元304中。或者控制开关单元301将第一子输入滤波单元305中的电能和谐振单元302中的电能传输至输出滤波单元304中。
应理解的是，控制电路33还可以更为精细地控制开关单元301将第一电源32提供的电能传输至输出滤波单元304中。下面本申请实施例提供一种控制方法，可以应用于如图7所对应的变换电路，该方法可以包括多个步骤，控制电路可以在一个控制周期内可以执行至少一个步骤。控制电路也可以在一个控制周期内多次执行一个步骤。如图14所示，方法包括如下步骤：
步骤S1401，控制电路33控制开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302中，直至谐振单元302电压大于第一预设阈值。
控制电路33控制RSCC 31工作前，可以通过执行预先配置的控制操作，实现控制开关单元301将第一电源32提供的电能传输至输出滤波单元304中。控制电路33可以先执行步骤S1401的控制操作，使得谐振单元302电压大于第一预设阈值，可以降低后续充电过程中产生的电流尖峰。第一预设阈值可以是第一电压范围内的最小值。
步骤S1402，控制电路33根据第一预设方式，执行操作1和操作2。其中，操作1为控制开关单元301将第一子输入滤波单元305N1中的电能和第二子输入滤波单元305N2中的电能传输至谐振单元302中，操作2为控制开关单元301将谐振单元302中的电能和第一子输入滤波单元305N1中的电能传输至输出滤波单元304中。
第一预设方式可以是“操作1，操作2，操作1，操作2…”的交替方式。控制电路33可以控制执行操作1的持续时长。例如通过控制高电平脉冲的持续时间，或者控制低电平脉冲的持续时间，实现控制操作1的持续时长，也即实现控制第一子输入滤波单元305N1和第二子输入滤波单元305N2对谐振单元302充电的持续时长。类似地，控制电路33也可以控制其它充电操作的持续时长。第一预设方式也可以是“操作2，操作1，操作2，操作1…”的交替方式。
控制电路33将第一子输入滤波单元305N1和谐振单元302作为能量传输的中间媒介，按照第一预设方式执行控制操作，可以将第二子输入滤波单元305N2中能量转移到输出滤波单元304中，也可以理解为第二子输入滤波单元305N2对输出滤波单元304充电。在步骤S1402中，第二子输入滤波单元305N2电压下降，第一子输入滤波单元305N1电压上 升。
步骤S1403，控制电路33判断输出滤波单元304电压是否大于第二预设阈值，若否，下一步执行步骤S1404，若是，下一步执行步骤S1405。
控制电路33在交替执行操作1和操作2的过程中，可以监控输出滤波单元304电压。若输出滤波单元304电压大于第二预设值可以视为完成对第二子输入滤波单元305N2对输出滤波单元304初步充电。
本申请实施例中，第二预设阈值可以是第二电压范围内的最小数值。其中第三电压范围内的数值可以是接近第一电源32输出电压Vin的0.3倍的电压值的任意数值。例如，第三电压范围中的最小值可以为0.3Vin，第二电压范围可以为[0.3Vin，Vin]。第二电压范围也可以由不连续的数值，如{0.3Vin，0.31Vin，0.315Vin，0.35Vin}。本申请实施例中，接近第一电源32输出电压Vin的0.3倍的电压值的数值范围可以根据RSCC 31中的元件参数进行配置。
步骤S1404，控制电路33判断第一子输入滤波单元305N1电压是否大于第三预设阈值，若是，下一步执行步骤S1402，若否，下一步执行步骤S1405。
控制电路33在交替执行操作1和操作2的过程中，也可以监控第一子输入滤波单元305N1电压。第三预设阈值可以是第二电压范围内的最小数值。第二电压范围中的最小值可以根据第一电源32提供的输入电压Vin和预设阈值ref确定。例如，预设阈值ref为30V，第二电压范围的最小值可为(0.5Vin+30)V。例如第二电压范围可以为[0.5Vin+ref，Vin]。第二电压范围也可以是由不连续的数值组成，例如，{0.48Vin+ref，0.485Vin+ref，0.5Vin+ref}。本申请实施例中，预设阈值ref可以根据RSCC 31中的元件的参数或者应用变换电路的场景进行配置。预设阈值ref也可以是根据预充电对变换电路工作性能影响的测试情况确定出的。示例性的，Vin为1500V，ref为30V，第三阈值可以为780V。
本申请实施例中步骤S1402至步骤S1403的过程，也可以通过控制电路33可以交替执行操作1和操作2，直至第一子输入滤波单元305N1电压在第二电压范围内。或者控制电路33可以交替执行操作1和操作2，直至第一子输入滤波单元305N1电压大于第二预设阈值实现。本申请实施例不对步骤S1403和步骤S1404执行的先后顺序进行具体限定。
步骤S1405，控制电路33判断谐振单元302电压是否大于输出滤波单元304电压与第一子输入滤波单元305N1电压之和，若是，下一步执行步骤S1406，若否，下一步执行步骤S1407。
控制电路33也可以监控谐振单元302电压，若确定谐振单元302电压大于输出滤波单元304电压与第一子输入滤波单元305N1电压之和，控制电路33可以控制开关单元301将谐振单元302中的电能和第一输入电源中的电能传输至输出滤波单元304。反之，控制电路33若确定谐振单元302电压小于或等于输入滤波单元电压与第一子输入滤波单元305N1电压之和，可以控制开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302中。
步骤S1406，控制开关单元301将谐振单元302中的电能和第一子输入滤波单元305N1中的电能传输至输出滤波单元304中，直至谐振单元302电压小于或等于输出滤波单元304电压与第一子输入滤波单元305N1电压之和。
控制电路33通过执行步骤S1406的操作，将第一子输入滤波单元305N1作为能量传输媒介，可使谐振单元302中的能量传输给输出滤波单元304，谐振单元302电压下降， 输出滤波单元304电压上升。
步骤S1407，控制电路33根据第二预设方式，执行操作3和操作4，其中，操作3为控制开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302中，操作3为控制开关单元301将谐振单元302中的电能传输至输出滤波单元304中。
控制电路33执行步骤S1406的过程中，谐振单元302电压下降，谐振单元302电压数值下降到小于或者等于输出滤波单元304电压与第一子输入滤波单元305N1电压之和时，谐振单元302无法继续将能量传输给输出滤波单元304，无法对输出滤波单元304充电。控制电路33执行操作3可以提升谐振单元302电压。控制电路33执行操作4可以使谐振单元302对输出滤波单元304充电。
本申请实施例中，第二预设方式可以是“操作3，操作4，操作3，操作4…”的交替方式。控制电路33可以控制执行操作3的持续时长，例如通过控制高电平脉冲的持续时间，或者控制低电平脉冲的持续时间，实现控制操作3的持续时长。类似地，控制电路33也可以控制操作4的持续时长。第二预设方式也可以是“操作4，操作3，操作4，操作3…”的交替方式。
控制电路33将谐振单元302作为能量传输的中间媒介，按照第二预设方式执行控制操作，可以将第一子输入滤波单元305N1中能量转移到输出滤波单元304中，可实现第一子输入滤波单元305N1对输出滤波单元304充电。控制电路33执行步骤S1407的过程中，第一子输入滤波单元305N1电压下降，输出滤波单元304电压上升。
步骤S1408，控制电路33判断输出滤波单元304电压是否大于第二预设阈值，若否，下一步执行步骤S1409，若是，下一步执行步骤S1410。
控制电路33在交替执行操作3和操作4的过程中，输出滤波单元304电压、第二子输入滤波单元305N2电压305N2、第一子输入滤波单元305N1电压均会发生改变。控制电路33若确定输出滤波单元304电压大于第二预设阈值可以结束执行步骤S1407，执行步骤S1410。控制电路33若确定输出滤波单元304电压小于或等于第二预设阈值，可以执行步骤S1409的判断过程。
步骤S1409，控制电路33判断第一子输入滤波单元305N1电压是否小于或等于第三预设阈值，若是，下一步执行步骤S1401，若否，下一步执行步骤S1407。
本申请实施例中，控制电路33执行步骤S1408和步骤S1409时，也可以执行步骤S1407。换句话说，控制电路33在执行步骤S1407的过程中，也可以执行步骤S1408和步骤S1409。
步骤S1410，控制电路33判断谐振单元302电压是否大于第四预设阈值，若是，下一步执行步骤S1411，若否，下一步执行步骤S1412。
本申请实施例中，第四预设阈值可以为大于第一电源32输入电压Vin的一半的数值，例如0.55Vin。
步骤S1411，控制电路33控制开关单元301将谐振单元302中的电能传输至输出滤波单元304中，直至谐振单元302电压大于或等于第一预设阈值。
步骤S1412，控制电路33判断谐振单元302电压是否小于第一预设阈值，若是，下一步执行步骤S1413，若否，下一步执行步骤S1414。
步骤S1413，控制电路33控制开关单元301将谐振单元302中的电能和第一子输入滤波单元305N1中的电能传输至输出滤波单元304中。
步骤S1414，控制电路33根据第三预设方式，执行操作5和操作6，直至输出滤波单 元304电压大于第一电源32提供的输入电压，其中，操作5为控制开关单元301将第一子输入滤波单元305N1中的电能和第二子输入滤波单元305N2中的电能传输至谐振单元302中，操作6为控制开关单元301将谐振单元302中的电能传输至输出滤波单元304中。
步骤S1415，控制电路33判断输出滤波单元304电压是否大于或等于第一电源32提供的输入电压，若是，下一步执行步骤S1414，若否，下一步执行步骤S1416。
步骤S1416，控制电路33控制开关单元301，使RSCC 31处于工作状态。
若输出滤波单元304电压大于或等于第一电源32提供的输入电压，可视为完成对输出滤波单元304预充电过程。控制电路33可以通过控制开关单元301，实现控制RSCC 31输出目标电压，使变换电路处于工作状态。
本申请实施例中，各步骤之间的顺序仅作为举例，并不作为各步骤先后执行顺序的具体限定。另外，本申请实施例还提供另一种控制方法，可以应用于如图13所对应的变换电路，该方法可以包括多个步骤，控制电路33可以在一个控制周期内可以执行至少一个步骤。路，该方法可以包括多个步骤，控制电路33可以在一个控制周期内可以执行至少一个步骤。控制电路33也可以在一个控制周期内多次执行一个步骤。如图15所示，方法包括如下步骤：
步骤S1501，控制电路33在每个控制周期中，向开关T5发送脉冲宽度为预设时长的控制信号，直至谐振单元302电压大于第一预设阈值。
控制电路33可以通过向开关发送脉冲信号，控制开关导通。控制电路33也可以通过不向开关发送脉冲信号，控制开关导通。本申请实施例中，以控制电路33通过向开关发送脉冲信号，控制开关导通作为一种举例对本申请实施例进行介绍，并不作为对本申请实施例的具体限定。
控制电路33执行步骤S1501的操作过程中，开关T5在接收到控制信号处于导通状态，开关T5可以保持导通状态，直至接收不到控制信号。控制开关T7、开关T6、开关T8在每个控制周期内处于断开状态。
通常，预设时长小于一个控制周期的时长。一个控制周期的时长可以是55微秒，预设时长可以是1.8％*55微秒，预设时长也可以是2％*55微秒。预设时长可以位于一个控制周期中的前半个周期，或者位于后半个周期。
开关T5处于导通状态，其它开关处于断开状态。如图16所示，开关单元301将第一子输入滤波单元305N1中的电能传输至谐振单元302中。控制电路33可以通过多次执行向开关T5发送脉冲宽度为预设时长的控制信号，使谐振单元302电压逐渐增大，直至谐振单元302电压大于第一预设阈值后，控制电路33可以执行步骤S1502。第一预设阈值可以是第一电压范围内的最小值。
在步骤S1501之前，控制电路33可以控制开关单元301中的全部开关处于断开状态，使第一电源32对第一子输入滤波单元305N1充电。
步骤S1502，控制电路33在第一控制周期中，持续向开关T5发送控制信号，在第一时段向开关T7发送脉冲宽度为预设时长的控制信号，在第二时段向开关T6发送脉冲宽度为预设时长的控制信号，其中，第一控制周期包括至少一个第一时段和至少一个第二时段，第一时段和第二时段无交集。
控制电路33可以控制开关T5在第一控制周期中均处于导通状态，控制开关T8在第一控制周期中均处于断开状态。控制电路33可以控制开关T7在第一控制周期中的第一时 段处于导通状态，控制开关T6在第一控制周期中的第二时段处于导通状态，第一时段和第二时段之间无交集。
第一控制周期也可以包括多个第一时段和多个第二时段。首个第一时段可以在首个第二时段之前，也可以在首个第二时段之后。两个相邻的第一时段之间，存在一个第二时段。控制电路33可以在第一控制周期中控制开关T7和开关T6交替处于导通状态。开关T7处于导通状态时，开关T6可以处于断开状态。开关T7处于断开状态时，开关T6可以处于导通状态。
在变换电路中，如图17所示，控制电路33控制开关T5处于导通状态，开关T8处于断开状态，开关T7处于导通状态，开关T6处于断开状态，开关T5和开关T7可将第一子输入滤波单元305N1中的电能和第二子输入滤波单元305N2中的电能传输至谐振单元302中。
如图18所示，控制电路33控制开关T5处于导通状态，开关T8处于断开状态，开关T7处于断开状态，开关T6处于导通状态，开关T5和开关T6可将第一子输入滤波单元305N1中的电能和谐振单元302中的电能传输至输出滤波单元304中。
步骤S1503，判断输出滤波单元304电压是否大于第二预设阈值，若否，下一步执行步骤S1504，若是，下一步执行步骤S1505。
控制电路33可以在执行步骤S1502的过程中，通过采集装置采集输出滤波单元304电压，并判断输出滤波单元304电压与第二预设阈值的大小关系。换句话说，步骤S1503和步骤S1502可以并行处理。
步骤S1504，控制电路33判断第一子输入滤波单元305N1电压是否大于第三预设阈值，若是，下一步执行步骤S1502，若否，下一步执行步骤S1505。
控制电路33可以在执行步骤S1502的过程中，通过采集装置采集第一子输入滤波单元305N1电压，并判断第一子输入滤波单元305N1电压与第三预设阈值的大小关系。换句话说，步骤S1504、步骤S1502、步骤S1503可以并行处理。控制电路33也可以在执行步骤S1502后，并行执行步骤S1504。
若第一子输入滤波单元305N1电压大于第三预设阈值，控制电路33再次执行步骤S1502中的操作。控制电路33在下一个控制周期中，执行步骤S1502的控制操作，也即将下一个控制周期作为第一控制周期。
本申请实施例中，控制电路33执行步骤S1503和步骤S1504，目的是通过判断输出滤波单元304电压或者第一子输入滤波单元305N1电压满足条件，确定结束执行步骤S1502的时机。本申请实施例提供了两种判定结束执行步骤S1502的条件。在实际应用场景中，控制电路33也可以仅通过判断输出滤波单元304电压满足条件，确定结束执行步骤S1502，也可以仅通过判断第一子输入滤波单元305N1电压满足条件，确定结束执行步骤S1502。换句话说，控制电路33在执行步骤S1502后，可以执行步骤S1503。或者在执行步骤S1502后，执行步骤S1504。
步骤S1505，控制电路33判断谐振单元302电压是否大于输出滤波单元304电压与第一子输入滤波单元305N1电压之和，若是，下一步执行步骤S1506，若否，下一步执行步骤S1507。
步骤S1506，控制电路33在每个控制周期中，向开关T6发送控制信号发送脉冲宽度为预设时长的控制信号，直至谐振单元302电压小于或等于输出滤波单元304电压与第一 子输入滤波单元305N1电压之和。
控制电路33可以控制开关T7、开关T5和开关T8在每个控制周期内处于断开状态，控制开关T6在每个控制周期中的预设时段内处于导通状态。如图18所示，控制电路33在每个控制周期中的预设时段内持续向开关T6发送控制信号，使得开关T6可以在所述预设时段内持续地处于导通状态，开关T6可以将谐振单元302中的能量传输给输出滤波单元304，可使输出滤波单元304电压缓缓上升。
本申请实施例中，步骤S1505和步骤S1506可以确定谐振单元302中具有较多电量的情形下，谐振单元302对输出滤波单元304进行充电。若谐振单元302中具有较少电量的情形下，控制电路33可以直接执行步骤S1507，使第一子输入滤波单元305N1对谐振单元302充电。
控制电路33在执行步骤S1506中过程中，谐振单元302电压由大于第一子输入滤波单元305N1电压与输出滤波单元304电压的总和，下降至等于第一子输入滤波单元305N1电压与输出滤波单元304电压的总和时，电路处于稳态，谐振单元302停止放电。
步骤S1507，控制电路33在第二控制周期中，持续向开关T6发送控制信号，在第三时段向开关T5发送脉冲宽度为预设时长的控制信号，在第四时段向开关T8发送脉冲宽度为预设时长的控制信号，其中，第二控制周期包括至少一个第三时段和至少一个第四时段，第三时段和第四时段无交集。
控制电路33执行步骤S1507时，可以控制开关T6在第二控制周期内均处于导通状态，开关T7在第二控制周期均处于断开状态。控制电路33可以控制开关T5在第二控制周期中的第三时段处于导通状态，控制开关T8在第二控制周期中的第四时段处于导通状态。其中，第三时段和第四时段之间无交集。
第二控制周期也可以包括多个第三时段和多个第四时段。首个第三时段可以在首个第四时段之前，也可以在首个第四时段之后。两个相邻的第三时段之间，存在一个第四时段。控制电路33可以在第二控制周期中控制开关T5和开关T8交替处于导通状态。开关T5处于导通状态时，开关T8可以处于断开状态。开关T8处于断开状态时，开关T5可以处于导通状态。
变换电路中，如图19所示，控制电路33控制开关T6处于导通状态，开关T7处于断开状态，开关T8处于导通状态，开关T5处于断开状态，开关T6和开关T8可将谐振单元302中的电能传输至输出滤波单元304中。
如图16所示，控制电路33控制开关T6处于导通状态，开关T7处于断开状态，开关T8处于断开状态，开关T5处于导通状态，开关T5可将第一子输入滤波单元305N1中的电能传输至输出滤波单元304中。
步骤S1508，控制电路33判断输出滤波单元304电压是否大于第二预设阈值，若否，下一步执行步骤S1509，若是，下一步执行步骤S1510。
控制电路33在执行步骤S1507过程中，输出滤波单元304电压、第二子输入滤波单元305N2电压305N2、第一子输入滤波单元305N1电压均会发生改变。控制电路33若确定输出滤波单元304电压大于第二预设阈值可以结束执行步骤S1507，执行步骤S1510。控制电路33若确定输出滤波单元304电压小于或等于第二预设阈值，可以执行步骤S1509的判断过程。
步骤S1509，控制电路33判断第一子输入滤波单元305N1电压是否小于或等于第三 预设阈值，若是，下一步执行步骤S1501，若否，下一步执行步骤S1507。
本申请实施例中，控制电路33执行步骤S1508和步骤S1509时，也可以执行步骤S1507。换句话说，控制电路33在执行步骤S1507的过程中，也可以执行步骤S1508和步骤S1509。控制电路33执行步骤S1503和步骤S1504，目的是通过判断输出滤波单元304电压或者第一子输入滤波单元305N1电压满足条件，确定结束执行步骤S1507的时机。本申请实施例提供了两种判定结束执行步骤S1507的条件。在实际应用场景中，控制电路33也可以仅通过判断输出滤波单元304电压满足条件，确定结束执行步骤S1507，也可以仅通过判断第一子输入滤波单元305N1电压满足条件，确定结束执行步骤S1507。换句话说，控制电路33在执行步骤S1507后，可以执行步骤S1508。或者在执行步骤S1507后，执行步骤S1509。
步骤S1510，控制电路33判断谐振单元302电压是否大于第四预设阈值，若是，下一步执行步骤S1511，若否，下一步执行步骤S1512。
本申请实施例中，第四预设阈值可以为大于第一电源32输入电压Vin的一半的数值，例如0.55Vin。
步骤S1511，控制电路33在每个控制周期中，持续向开关T6发送控制信号，向开关T8发送脉冲宽度为预设时长的控制信号，直至谐振单元302电压小于或等于第四预设阈值。
在变换电路中，如图19所示，控制电路33控制开关T6处于导通状态，开关T7处于断开状态，开关T8处于导通状态，开关T5处于断开状态，开关T6和开关T8可将谐振单元302中的电能传输至输出滤波单元304中。控制电路33通过执行步骤S1511，控制开关T6和开关T8将谐振单元302中的电能传输至输出滤波单元304中，降低谐振单元302两端的电压。控制电路33可以确定谐振单元302电压小于或等于第四预设阈值后，执行步骤S1511。
步骤S1512，控制电路33判断谐振单元302电压是否小于第一预设阈值，若是，下一步执行步骤S1513，若否，下一步执行步骤S1514。
步骤S1513，控制电路33在每个控制周期中，向开关T5发送脉冲宽度为预设时长的控制信号，直至谐振单元302电压大于第一预设阈值。
控制电路33在执行步骤S1513过程中，开关T5将第一子输入滤波单元305N1中的电能传输至谐振单元302中，如图16所示。控制电路33也可以在执行步骤S1513过程中，可以监控谐振单元302电压是否在第一预设阈值和第四预设阈值之间。控制电路33在执行步骤S1513过程中若确定谐振单元302电压在第一预设阈值和第四预设阈值之间，也可以直接执行步骤S1514。
本申请实施例中，控制电路33执行步骤S1510至步骤S1512的过程可理解为，控制电路33通过对开关单元301中开关的控制，调整谐振单元302的电压值大于第一预设阈值。
步骤S1514，控制电路33在第三控制周期中，在第五时段向开关T5和开关T7发送脉冲宽度为预设时长的控制信号，在第六时段向开关T6和开关T8发送脉冲宽度为预设时长的控制信号，其中，第三控制周期包括至少一个第五时段和至少一个第六时段，第五时段和第六时段无交集。
控制电路33控制开关T5和开关T7在第三控制周期中的第五时段处于导通状态，如图17所示，开关T5和开关T7可以将第一子输入滤波单元305N1中的电能和第二子输入 滤波单元305N2中的电能传输至谐振单元302中。
控制电路33控制开关T6和开关T8在第三控制周期中的第六时段处于导通状态，如图19所示，开关T6和开关T8可以将谐振单元302中的电能传输至输出滤波单元304中。
步骤S1515，控制电路33判断输出滤波单元304电压是否不小于第一电源32提供的输入电压，若是，下一步执行步骤S1514，若否，下一步执行步骤S1516。
步骤S1516，控制电路33控制开关单元301，使RSCC 31输出目标电压。
控制电路33可以按照预设控制方式，控制开关单元301中的开关，使得RSCC 31可以输出目标电压，从而控制变换电路处于工作状态。
本申请实施例中，各步骤之间的顺序仅作为举例，并不作为各步骤先后执行顺序的具体限定。
本申请提供的变换电路以及控制方法可以应用于光伏发电系统、电动汽车、可再生能源系统等使用电力电子变换器的场景中。如图20所示，本申请实施例提供的变换电路中的第一电源可以包括至少一个光伏组串和直流-直流升压电路。直流-直流升压电路与至少一个光伏组串连接，用于将至少一个光伏组串提供的电压进行升压处理。直流-直流升压电路的输出端可以作为第一电源的两极分别与RSCC的第一输入端和第二输入端连接，为RSCC提供输入电压。
本申请还提供一种光伏系统，如图21所示，系统包括至少两个光伏组串、最大功率跟踪(Maximum Power Point Tracking，MPPT)汇流箱、直流交流逆变电路以及线缆等。直流-交流逆变电路的输出端与电网连接。光伏发电系统还包括控制电路，可以对控制光伏组串，MPPT汇流箱和直流-交流逆变电路进行控制。
MPPT汇流箱可以包括两个直流-直流升压电路和一个RSCC。每个直流-直流升压电路与至少一个光伏组串连接，直流-直流升压电路的正极输入端与光伏组串的正极相连，直流-直流升压电路的负极输入端与光伏组串的负极相连。其中，RSCC可以是前述实施例中提供的任意一种RSCC。RSCC中的开关单元与控制电路连接。
两个直流-直流升压电路中的一个直流-直流升压电路的正极输出端与直流-交流逆变电路的正极输入端连接。便于描述，将两个直流-直流升压电路分别记为第一直流-直流升压电路和第二直流-直流升压电路。其中，第二直流-直流升压电路的正极输出端与直流-交流逆变电路的正极输入端连接。第二直流-直流升压电路的负极输出端与直流-交流逆变电路类的零电平端连接。
RSCC的正极输入端M1与第一直流-直流升压电路的正极输出端连接，RSCC的负极输入端S2分别与第一直流-直流升压电路的负极输出端和第二直流-直流升压电路的负极输出端连接。RSCC的正极输出端M4分别与第二直流-直流升压电路的负极输出端和直流-交流逆变电路的零电平端连接。RSCC的负极输出端M4与直流-交流逆变电路的负极输入端连接。
本申请实施例中，RSCC的负极输入端M2和正极输出端M4均与第二直流-直流升压电路的负极输出端连接。RSCC的负极输入端M2和正极输出端M4可以是同一个端点，如前述实施例中RSCC 31的第二输入端S2。RSCC的正极输入端M1可以是RSCC 31的第一输入端S1。RSCC的负极输出端M3可以为RSCC 31的输出端S3。第一直流-直流升压电路和与第一直流-直流升压电路连接的光伏组串可以作为电源，为RSCC提供输入电压。
第一直流-直流升压电路所连接的光伏组串，与第一直流-直流升压电路可以作为前述 实施例中的第一电源为RSCC提供电能。在本申请实施例提供的光伏发电系统中，RSCC可以用于将第一直流-直流升压电路提供的输入电压转化为极性相反为的目标电压，以保护与第一直流-直流升压电路相连的光伏组串的元件性能。
应理解的是，本申请实施例提供的光伏系统中，第一直流-直流升压电路、与第一直流-直流升压电路连接的光伏组串可以视为前述实施例中的第一电源，为与第一直流-直流升压电路的RSCC提供输入电压。换句话说，本申请实施提供的光伏系统可以包括如前述实施例中提供的变换电路。
本申请提供的光伏系统中的MMPT汇流箱以及直流-交流逆变电路可以组成组串式高压型逆变器。本申请提供的光伏系统也可视为包括组串式高压逆变器的系统。
一种可能的实施方式中，如图22所示，光伏系统可以包括直流-交流逆变电路、多个MPPT汇流箱和多个光伏组串。该光伏系统也可以称为基于组串式高压型逆变器的光伏发电系统。每个MPPT汇流箱中包括RSCC和两个直流-直流升压电路，其中，两个直流-直流升压电路分别为第二直流-直流升压电路和第一直流-直流升压电路。每个MPPT汇流箱中RSCC的正极输出端连接直流-交流逆变电路的零电平端，RSCC的负极输出端连接直流逆变电路的负极输入端。每个MPPT中的第二直流升压变换电路的正极输出端与直流-交流逆变电路的正极输入端连接。
在光伏发电系统工作前，对每个MPPT中的RSCC进行预充电，可以保护RSCC的输出滤波电容等元件的性能，也可以保障RSCC的工作性能，从而实现保护光伏发电系统工作性能。并且，对RSCC进行预充电，不需要增加额外的元件，提升了RSCC的功率密度，也降低了光伏发电系统的复杂度，可以简化光伏发电系统的控制流程。
本申请实施例提供的光伏系统、光伏发电系统可以应用于大型光伏电站应用场景、中小型分布式电站应用场景、户用光伏发电系统应用场景。光伏系统、光伏发电系统可以将光能转化为直流电，然后将直流电转化为交流电，为负载或电网提供交流电，也可称为光伏逆变系统，或光伏逆变器系统。
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的保护范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (19)

  1. 一种变换电路，其特征在于，包括：第一电源、谐振开关电容变换器RSCC和控制电路；
    所述RSCC包括开关单元、输出滤波单元、第一输入端S1，第二输入端S2和输出端S3，所述开关单元连接在所述第一输入端S1和所述第二输入端S2之间，所述输出滤波单元连接在所述第二输入端S2和所述输出端S3之间；
    所述第一电源的一极与所述第一输入端S1连接，所述第一电源的另一极与所述第二输入端S2连接，所述第一电源用于为所述RSCC提供输入电压；
    所述控制电路与所述开关单元连接，用于在控制所述RSCC工作前，控制所述RSCC中的所述开关单元将所述第一电源提供的电能传输至所述输出滤波单元。
  2. 如权利要求1所述的电路，其特征在于，所述RSCC还包括谐振单元和钳位单元；所述钳位单元与所述输出滤波单元并联；所述开关单元与所述谐振单元的一端连接，所述谐振单元的另一端与所述钳位单元连接；
    所述控制电路控制所述RSCC中的开关单元将所述第一电源提供的电能传输至所述输出滤波单元时，具体用于：
    控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元；
    控制所述开关单元将所述谐振单元中的电能传输至所述输出滤波单元。
  3. 如权利要求2所述的电路，其特征在于，所述控制电路控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元时，所述第一电源、所述开关单元、所述谐振单元、所述钳位单元形成第一通路，所述开关单元和所述第二输入端S2之间断路，所述钳位单元与所述输出端S3之间断路；
    所述控制电路控制所述开关单元将所述谐振单元中的电能传输至所述输出滤波单元中时，所述开关单元、所述谐振单元、所述钳位单元、所述输出滤波单元形成第二通路，所述钳位单元与所述第二输入端S2之间断路。
  4. 如权利要求2或3所述的电路，其特征在于，所述开关单元包括串联的第一开关和第二开关，所述第一开关的一端与所述第一输入端S1连接，所述第一开关的另一端与所述第二开关的一端连接，所述第二开关的另一端与所述第二输入端S2连接；
    所述控制电路控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元时，所述控制电路具体用于：
    控制所述第一开关导通以及所述第二开关断开；
    所述控制电路控制所述开关单元将所述谐振单元中的电能传输至所述输出滤波单元中时，所述控制电路具体用于：
    控制所述第一开关断开以及所述第二开关导通。
  5. 如权利要求2所述的电路，其特征在于，所述RSCC还包括输入滤波单元，所述输入滤波单元与所述开关单元并联；所述输入滤波单元用于存储所述第一电源提供的电能；
    所述输入滤波单元包括第一子输入滤波单元和第二子输入滤波单元，所述第一子输入滤波单元与所述第二子输入滤波单元串联连接，所述第一子输入滤波单元与所述第二子输入滤波单元连接的一端与所述开关单元连接；
    所述控制电路控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元时， 具体用于：
    控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能传输至所述谐振单元中；或者，
    控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能和提供给所述第二子输入滤波单元中的电能传输至所述谐振单元中。
  6. 如权利要求5所述的电路，其特征在于，所述控制电路控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能传输至所述谐振单元中时，所述第一子输入滤波单元、所述开关单元、所述谐振单元、所述钳位单元之间形成第三通路，所述开关单元与所述第一输入端S1之间断路，所述开关单元与所述第二输入端S2之间断路，所述钳位单元与所述输出滤波单元断路；
    所述控制电路控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能和所述第一电源提供给所述第二子输入滤波单元中的电能传输至所述谐振单元中时，所述第一子输入滤波单元、所述第二子输入滤波单元、所述开关单元、所述谐振单元、所述钳位单元之间形成第四通路，所述开关单元与所述第二输入端S2之间断路，所述钳位单元与所述输出滤波单元之间断路。
  7. 如权利要求5所述的电路，其特征在于，所述控制电路还用于控制所述开关单元将所述第一子输入滤波单元中的电能传输至所述输出滤波单元中。
  8. 如权利要求5至7任一所述的电路，其特征在于，所述控制电路控制所述开关单元将所述谐振单元中的电能传输至所述输出滤波单元中时，所述谐振单元、所述开关单元、所述输出滤波单元和所述钳位单元形成第五通路，所述开关单元与所述第一子输入滤波单元之间断路，所述开关单元与所述第二输入端S2之间断路。
  9. 如权利要求7所述的电路，其特征在于，所述控制电路控制所述开关单元将所述第一子输入滤波单元中的电能传输至所述输出滤波单元中时，所述第一子输入滤波单元、所述开关单元、所述谐振单元、所述钳位单元、所述输出滤波单元形成第六通路，所述开关单元与所述第二输入端S2之间断路，所述开关单元与所述第一输入端S1之间断路，所述钳位单元与所述第二输入端S2之间断路。
  10. 如权利要求5-9任一所述的电路，其特征在于，所述开关单元包括串联连接的第一二极管和第二二极管，以及依次串联连接的第三开关、第四开关、第五开关和第六开关；所述第一二极管的阴极与所述第三开关和所述第四开关之间的连接点连接，所述第一二极管的阳极分别连接所述第二二极管的阴极、所述第一子输入滤波单元和所述第二子输入滤波单元；所述第二二极管的阳极与所述第五开关和所述第六开关之间的连接点连接。
  11. 如权利要求10所述的电路，其特征在于，所述控制电路控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能传输至所述谐振单元中时，所述控制电路具体用于：
    控制所述第四开关导通，以及所述第三开关、所述第五开关和所述第六开关断开；或者，
    所述控制电路控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能和提供给所述第二子输入滤波单元中的电能传输至所述谐振单元中时，所述控制电路具体用于：
    控制所述第三开关和所述第四开关导通，以及所述第五开关和所述六开关断开。
  12. 如权利要求10所述的电路，其特征在于，所述控制电路控制所述开关单元将所述第一子输入滤波单元中的电能传输至所述输出滤波单元中时，所述控制电路具体用于：
    控制所述第五开关导通，所述第三开关、所述第四开关和所述第六开关断开。
  13. 如权利要求10所述的电路，其特征在于，所述控制电路控制所述开关单元将所述谐振单元中的电能传输至所述输出滤波单元中时，所述控制电路具体用于：
    控制所述第三开关和所述第四开关断开，所述第五开关和所述第六开关导通。
  14. 如权利要求1-13任一项所述的电路，其特征在于，所述第一电源包括：至少一个光伏组串和第一直流-直流升压电路；
    所述至少一个光伏组串的正极与所述第一直流-直流升压电路的正极输入端连接，所述至少一个光伏组串的负极与所述第一直流-直流升压电路的负极输入端连接；
    所述第一直流-直流升压电路的正极输出端连接所述第一输入端S1，所述第一直流-直流升压电路的负极输出端连接所述第二输入端S2；
    所述第一直流-直流升压电路用于将所述至少一个光伏组串提供的电压转化为所述输入电压。
  15. 一种变换电路预充电控制方法，其特征在于，应用于变换电路，所述变换电路包括第一电源、谐振开关电容变换器RSCC，所述RSCC包括开关单元和输出滤波单元，所述方法包括：
    控制所述开关单元将所述第一电源提供的电能传输至所述输出滤波单元；
    若确定所述输出滤波单元电压大于预设阈值，控制所述RSCC工作。
  16. 如权利要求15所述的方法，其特征在于，所述RSCC还包括谐振单元；所述控制所述开关单元将所述第一电源提供的电能传输至所述输出滤波单元，包括：
    控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元；
    控制所述开关单元将所述谐振单元中的电能传输至所述输出滤波单元。
  17. 如权利要求16所述的方法，其特征在于，所述RSCC还包括输入滤波单元，所述输入滤波单元包括第一子输入滤波单元和第二子输入滤波单元；所述方法还包括：
    控制所述开关单元将所述第一子输入滤波单元中的电能传输至所述输出滤波单元中。
  18. 如权利要求17所述的方法，其特征在于，所述控制所述开关单元将所述第一电源提供的电能传输至所述谐振单元，包括：
    控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能传输至所述谐振单元中；或者，
    控制所述开关单元将所述第一电源提供给所述第一子输入滤波单元中的电能和提供给所述第二子输入滤波单元中的电能传输至所述谐振单元中。
  19. 一种光伏系统，其特征在于，包括至少一个如权利要求14所述的变换电路、多个光伏组串、至少一个第二直流-直流升压电路、直流-交流逆变电路；
    每个第二直流-直流升压电路的正极输出端与所述直流-交流逆变电路的正极输入端连接，所述每个第二直流-直流升压电路的负极输出端分别与一个所述变换电路中的RSCC的第二输入端S2和所述直流-交流逆变电路的零电平端连接；其中，每个第二直流-直流升压电路的负极输出端连接不同所述变换电路中的RSCC的第二输入端S2；
    每个所述变换电路中的RSCC的输出端S3与所述直流-交流逆变电路的负极输入端连接；
    每个所述第二直流-直流升压电路的正极输入端连接至少一个光伏组串的正极，所述每个第二直流-直流升压电路的负极输入端连接所述至少一个光伏组串的负极；
    每个所述第二直流-直流升压电路用于将所连接的光伏组串提供的电压进行升压处理得到第一输入电压，并向所述直流-交流逆变电路提供所述第一输入电压；
    所述变换电路中的所述RSCC工作时，向所述直流-交流逆变电路提供第二输入电压，其中，所述第二输入电压的极性与所述第一输入电压的极性相反；
    所述直流-交流逆变电路的输出端用于与电网连接，以将所述第一输入电压和所述第二输入电压转化为交流电压后提供给所述电网。
PCT/CN2021/074236 2021-01-28 2021-01-28 一种变换电路、变换电路预充电控制方法及光伏系统 WO2022160207A1 (zh)

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