WO2019080493A1 - 逆变器的均流方法、装置、逆变系统及无线充电系统 - Google Patents

逆变器的均流方法、装置、逆变系统及无线充电系统

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Publication number
WO2019080493A1
WO2019080493A1 PCT/CN2018/088352 CN2018088352W WO2019080493A1 WO 2019080493 A1 WO2019080493 A1 WO 2019080493A1 CN 2018088352 W CN2018088352 W CN 2018088352W WO 2019080493 A1 WO2019080493 A1 WO 2019080493A1
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WO
WIPO (PCT)
Prior art keywords
inverter
current
reactive current
active
reactive
Prior art date
Application number
PCT/CN2018/088352
Other languages
English (en)
French (fr)
Inventor
毛云鹤
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP18869696.7A priority Critical patent/EP3691104B1/en
Publication of WO2019080493A1 publication Critical patent/WO2019080493A1/zh
Priority to US16/856,435 priority patent/US11677332B2/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
    • 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
    • H02M7/53—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 using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—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 using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—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 using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • 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
    • H02M7/4807—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 having a high frequency intermediate AC stage
    • 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
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/48—Controlling the sharing of the in-phase component
    • 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
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/50—Controlling the sharing of the out-of-phase component
    • 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
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
    • 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
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/20—Circuit arrangements or systems for wireless supply or distribution of electric power using microwaves or radio frequency waves
    • 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
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/02—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from ac mains by converters
    • H02J7/025—
    • 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
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33573—Full-bridge at primary side of an isolation transformer
    • 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
    • H02M7/53—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 using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—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 using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • 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
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/10—Parallel operation of dc sources
    • H02J1/102—Parallel operation of dc sources being switching 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
    • 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
    • H02M7/493—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 the static converters being arranged for operation in parallel

Definitions

  • the present application relates to the field of power electronics, and in particular, to a current sharing method, device, inverter system, and wireless charging system for an inverter.
  • wired charging requires the operator to manually plug in and out the charging gun, which is in danger of being shocked during thunderstorms.
  • wireless charging and wired charging face the same problem, that is, wireless charging also needs to develop in the direction of fast charging.
  • wireless charging systems to high power there are single-machine structures and multi-machine parallel structures.
  • the parallel connection between high-frequency modules may result in uneven output current of each parallel module due to parameter differences and drive delays of each parallel module.
  • Some module outputs The current is large, and some of the output current is small, which causes inconsistent heating between the inverters, and even causes a bomber in severe cases.
  • the traditional technology is to reserve a larger design margin, so that the most heat-generating module can meet the temperature rise requirements, but too much redundant design will lead to a reduction in power density and reliability of the system.
  • the application provides a current sharing method, a device, an inverter system and a wireless charging system of an inverter, which can realize the current sharing of the inverter output current and high reliability.
  • a current sharing method for an inverter for realizing current sharing when a high frequency parallel connection is performed at an output end of a multi-inverter, the multi-inverter including at least two inverters: a first inverse And a second inverter; the outputs of the first inverter and the second inverter are connected in parallel and inductive, the method comprising:
  • the difference between the active current difference of the transformer and the active current difference of the second inverter respectively adjusts a phase difference between the carrier signal generated by the first inverter and the second inverter and the carrier synchronization signal, so that the first An output current of an inverter is equalized with an output current of the second inverter, and the carrier synchronization signal is a pulse signal simultaneously input to the two inverters at the same time.
  • the reactive current of the inverter is adjusted by adjusting the amplitude of the input voltage of the inverter, so that the reactive current output of each inverter is equalized;
  • the phase difference between the carrier self-carrier signal and the carrier synchronization signal adjusts the active current output by the inverter, so that the active current output by each inverter is equalized.
  • adjusting the input voltage amplitude of the first inverter according to the reactive current difference of the first inverter includes:
  • the first inverter self-carrier signal and the carrier synchronization signal are adjusted according to the active current difference of the first inverter
  • the phase difference between the two includes:
  • the reactive current of the collected inverter is made to be different from the reactive current reference value, and the reactive current difference is obtained.
  • the reactive current difference is input to the reactive current regulator for processing, and the voltage trimming amount is obtained, and the voltage is finely adjusted.
  • the amount and the voltage adjustment amount set value are superimposed to obtain the input voltage reference value, and the input voltage amplitude of the inverter is adjusted according to the input voltage reference value, thereby realizing the regulation of the reactive current.
  • the reactive current adjustment method of the inverter provided in this embodiment can adjust the input voltage amplitude of each inverter to achieve the current sharing current of each inverter. Moreover, the reactive current outputted by each inverter reaches a current sharing, and each inverter can be in a soft switching (ZVS, Zero Voltage Switch) working state, and the switching loss of each inverter is reduced.
  • ZVS Zero Voltage Switch
  • the obtaining the active current of the first inverter and the active current of the second inverter specifically :
  • the obtaining the reactive current of the first inverter and the reactive current of the second inverter specifically includes:
  • the inverter output current is a reactive current of the second inverter.
  • the active current of the collected inverter is compared with the active current reference value to obtain the active current difference, and the active current difference is input into the active current regulator for processing, and the angle fine adjustment amount is obtained.
  • the angle adjustment amount and the angle adjustment amount set value are superimposed to obtain a carrier signal phase reference value, and then the phase difference between the carrier self-carrier signal and the carrier synchronization signal is adjusted according to the carrier signal phase reference value, and further Realize the adjustment of the active current.
  • the output voltages of the first inverter and the second inverter are connected in parallel, and the output voltage is The frequency is the same as the switching frequency of the first inverter and the second inverter.
  • the reactive current reference value is a reactive current of the first inverter and a second inverter An average value of the reactive current, the active current reference value being an average of the active current of the first inverter and the active current of the second inverter.
  • an inverter current equalization device for achieving current sharing when the output ends of the multiple inverters are connected in high frequency, the multiple inverters including at least two inverters: a first inverter And a second inverter; the outputs of the first inverter and the second inverter are connected in parallel with each other and are inductive,
  • the current sharing device includes: a first inverter controller, a second inverter controller, a first inductive component, and a second inductive component;
  • An output end of the first inverter is connected to a common parallel point through the first inductive component, and an output end of the second inverter is connected to a common parallel point through the second inductive component, the first inductive component Making an output of the first inverter inductive, the second inductive component causing an output of the second inverter to be inductive;
  • the first inverter controller is configured to compare a reactive current of the first inverter with a reactive current reference value to obtain a reactive current difference of the first inverter, according to the first inverse
  • the reactive current difference of the transformer adjusts the input voltage amplitude of the first inverter; and is also used to compare the active current of the first inverter with the active current reference value to obtain the active power of the first inverter a current difference, the phase difference between the carrier signal generated by the first inverter itself and the carrier synchronization signal is adjusted according to the active current difference of the first inverter; the carrier synchronization signal is for the two inverters simultaneously a pulse signal input simultaneously;
  • the second inverter controller is configured to compare the reactive current of the second inverter with a reactive current reference value to obtain a reactive current difference of the second inverter, according to the second inverse
  • the reactive current difference of the transformer adjusts the input voltage amplitude of the second inverter; and is also used to compare the active current of the second inverter with the active current reference value to obtain the active power of the second inverter
  • the current difference value adjusts a phase difference between the carrier signal generated by the second inverter itself and the carrier synchronization signal according to the active current difference of the second inverter.
  • the reactive current of the inverter is adjusted by adjusting the amplitude of the input voltage of the inverter, so that the reactive current output by each inverter is equalized;
  • the phase difference between the carrier's own carrier signal and the carrier synchronization signal adjusts the active current output by the inverter so that the active current output by each inverter flows.
  • the reactive current and the active current output by each inverter are both currentized, so that the current output of each inverter can be equalized.
  • each inverter can be ensured only by adjusting the input voltage amplitude of each inverter and the phase difference between the carrier signal and the carrier synchronization signal.
  • the output current is equalized.
  • the current sharing device provided by the above embodiment in the high frequency parallel connection of the inverter can select the host and the slave in a predetermined mechanism in the inverter controllers such as the first inverter controller and the second inverter controller. machine.
  • the carrier synchronization signal can be generated by the host and sent to the slave.
  • the first inverter controller and the second inverter controller select a master and a slave by using a predetermined mechanism
  • the carrier synchronization signal is generated by the host and sent to the slave.
  • the method further includes: a first reactive current sampling circuit, a first active current sampling circuit, and a second reactive current sampling circuit And a second active current sampling circuit;
  • the first reactive current sampling circuit is configured to obtain a reactive current of the first inverter
  • the first active current sampling circuit is configured to obtain an active current of the first inverter
  • the second reactive current sampling circuit is configured to obtain a reactive current of the second inverter
  • the second active current sampling circuit is configured to obtain an active current of the second inverter
  • the host is configured to obtain an average value of the reactive current from the reactive current of the first inverter and the reactive current of the second inverter, and use the average value of the reactive current as the reactive current reference a value, and the reactive current reference value is sent to the slave; and is further configured to obtain an active current average from an active current of the first inverter and an active current of the second inverter, The active current average is used as the active current reference value, and the active current reference value is sent to the slave.
  • the method further includes: a first reactive current sampling circuit, a first active current sampling circuit, and a second reactive current sampling circuit And a second active current sampling circuit;
  • the first reactive current sampling circuit is configured to obtain a reactive current of the first inverter
  • the first active current sampling circuit is configured to obtain an active current of the first inverter
  • the second reactive current sampling circuit is configured to obtain a reactive current of the second inverter
  • the second active current sampling circuit is configured to obtain an active current of the second inverter
  • the first inverter controller is configured to obtain an average value of reactive current from a reactive current of the first inverter and a reactive current of the second inverter, and use the average value of the reactive current as
  • the reactive current reference value is further configured to obtain an active current average value from an active current of the first inverter and an active current of the second inverter, and use the average value of the active current as the active current reference value;
  • the second inverter controller is configured to obtain an average value of the reactive current from the reactive current of the first inverter and the reactive current of the second inverter, and use the average value of the reactive current as
  • the reactive current reference value is further configured to obtain an active current average value from an active current of the first inverter and an active current of the second inverter, and use the average value of the active current as the active current reference value.
  • an inverter system including the current sharing device, and further includes at least two inverters: a first inverter and a second inverter;
  • the input end of the first inverter is connected to the first adjustable power source
  • the input end of the second inverter is connected to the second adjustable power source.
  • the method further includes: a first DC-DC converter and a second DC-DC converter;
  • the first adjustable power source is a first DC adjustable power source
  • the second adjustable power source is a second DC adjustable power source
  • the first DC-DC converter is configured to convert a voltage output by the first DC adjustable power supply to an input end of the first inverter
  • the second DC-DC converter is configured to convert a voltage output by the second DC adjustable power supply to an input end of the second inverter
  • the method further includes: a first AC-DC converter and a second AC-DC converter;
  • the first adjustable power source is a first AC adjustable power source
  • the second adjustable power source is a second AC adjustable power source
  • the first AC-DC converter is configured to rectify the first AC adjustable power source into DC power and then deliver the signal to the input end of the first inverter;
  • the second AC-DC converter is configured to rectify the second AC adjustable power supply to DC power and then to the input end of the second inverter.
  • a fourth aspect provides a wireless charging system, including the current sharing device, further comprising at least two inverters: a first inverter and a second inverter;
  • the method further includes: a first adjustable power source, a second adjustable power source, a wireless transmitting circuit, and a wireless receiving circuit;
  • the input end of the first inverter is connected to the first adjustable power source
  • the input end of the second inverter is connected to the second adjustable power source
  • An output end of the first inverter is connected to an input end of the wireless transmitting circuit
  • An output end of the second inverter is connected to an input end of the wireless transmitting circuit
  • the wireless transmitting circuit transmits power through a wireless manner, and the wireless receiving circuit wirelessly receives power transmitted by the wireless transmitting circuit to supply power to the load.
  • the current sharing device provided by the above embodiments can also be applied to the field of induction heating, in which case the load can be a device requiring heating, for example, various profiles require heating to melt or deform. Specifically, it may be casting of an aluminum device or the like.
  • the wireless transmitting circuit includes a transmitting compensation network and a transmitting coil; and the wireless receiving circuit includes a receiving compensation network and a receiving coil;
  • An input end of the transmission compensation network is used as an input end of the wireless transmission circuit, and an output end of the transmission compensation network is connected to the transmitting coil;
  • the receiving coil is connected to an input end of the receiving compensation network, and an output end of the receiving compensation network is connected to a load.
  • the embodiments of the present application have the following advantages:
  • the method is applied to the case where at least two inverter high-frequency outputs are connected in parallel, and each inverter output is inductive.
  • the reactive current of each inverter is compared with the reactive current reference value to obtain the reactive current difference of each inverter, and the respective inverses are adjusted according to the reactive current difference of each inverter.
  • Transformer input voltage amplitude compare the active current of each inverter with the active current reference value to obtain the active current difference of each inverter, and adjust each inverter according to the active current difference of each inverter The phase difference between the carrier signal and the carrier synchronization signal, wherein the carrier synchronization signal is a given signal.
  • the current sharing method adjusts the reactive current of the inverter output by adjusting the amplitude of the input voltage of the inverter under the condition that the output end of the inverter is inductive, so that the output of each inverter is The reactive current is equalized; the active current outputted by the inverter is adjusted by adjusting the phase difference between the carrier signal of each inverter and the carrier synchronization signal, so that the active current output by each inverter is equalized.
  • the reactive current and the active current output from each inverter are equalized, which ensures the current sharing of the output of each inverter.
  • the current sharing method does not need to set a large number of large-scale hardware electronic devices in the circuit, and can ensure each inverse only by adjusting the input voltage amplitude of each inverter and the phase difference between the self-carrier signal and the carrier synchronization signal.
  • the current output of the transformer is currentized.
  • FIG. 1 is a flowchart of a current sharing method for a high frequency parallel connection of an inverter according to Embodiment 1 of the present application;
  • Figure 2a is a waveform diagram of the inverter output current and the inverter output voltage
  • 2b is a schematic diagram showing a droop characteristic curve of an input voltage of the inverter and a reactive current of the inverter;
  • 2c is a schematic diagram showing a phase difference between a synchronous carrier signal and a carrier signal of the inverter and a droop characteristic curve of the active current;
  • FIG. 3 is a circuit diagram of a current sharing circuit according to an embodiment of the present application.
  • FIG. 4 is a flowchart of a method for adjusting reactive current of an inverter provided by Embodiment 2 of the method of the present application;
  • FIG. 5 is a schematic diagram of a reactive current adjustment process of an inverter provided in Embodiment 2 of the method of the present application;
  • FIG. 6 is a flowchart of a method for adjusting an active current of an inverter according to Embodiment 3 of the present application;
  • Figure 7a is a waveform diagram of an inverter output voltage and a carrier synchronization signal
  • FIG. 7b is a schematic diagram of an active current adjustment process of an inverter provided in Embodiment 3 of the present application.
  • FIG. 8 is a structural diagram of a current sharing device when a high frequency parallel connection of an inverter according to Embodiment 1 of the present application.
  • Figure 8b is a structural diagram of an H-bridge inverter
  • FIG. 9 is a structural diagram of a current sharing device when a high frequency parallel connection of an inverter according to Embodiment 2 of the present application.
  • FIG. 10 is a structural diagram of a current sharing device when a high frequency parallel connection of an inverter according to Embodiment 3 of the present application;
  • FIG. 11 is a structural diagram of an inverter system in which a high frequency parallel connection of an inverter is provided according to Embodiment 1 of the present application;
  • FIG. 12 is a structural diagram of an inverter system when a high frequency parallel connection of an inverter according to Embodiment 2 of the present application;
  • FIG. 13 is a structural diagram of another inverter system when the inverter is connected in high frequency in parallel according to Embodiment 2 of the present application;
  • FIG. 14 is a structural diagram of an inverter system when a high frequency parallel connection of an inverter is provided in Embodiment 3 of the system of the present application;
  • FIG. 15 is a structural diagram of another inverter system when the inverter is connected in high frequency in parallel according to Embodiment 3 of the system of the present application;
  • FIG. 16 is a structural diagram of another inverter system when the inverter is connected in high frequency in parallel according to Embodiment 3 of the system of the present application.
  • the embodiment of the present application provides a current sharing method for an inverter, which is used to ensure current sharing between respective inverters connected in parallel at an output end.
  • the inverters When multiple inverters are connected in parallel, the inverters may have different output currents due to differences in parameters and drive delays, that is, some inverter output currents. Larger, some inverter output current is smaller, which leads to different heating of each inverter. In severe cases, the explosion phenomenon may even occur.
  • the embodiment of the present application provides a current sharing method when a high frequency parallel connection of an inverter is applied to a case where at least two high frequency output ends of the inverter are connected in parallel, and each inverter output is The end is emotional.
  • the current sharing method adjusts the reactive current of the inverter by adjusting the amplitude of the input voltage of the inverter under the condition that the output of the inverter is inductive, so that the output of each inverter is not
  • the working current is equalized;
  • the active current outputted by the inverter is adjusted by adjusting the phase difference between the carrier signal of each inverter and the carrier synchronization signal, so that the active current output by each inverter is equalized.
  • the reactive current and the active current output from each inverter are equalized, which ensures the current sharing of the output of each inverter.
  • the current sharing method does not need to set a large-sized hardware electronic device in the circuit, and can ensure each inverter only by adjusting the input voltage amplitude of each inverter and the phase difference between the self-carrier signal and the carrier synchronization signal.
  • the output current is equalized.
  • FIG. 1 a flow chart of a current sharing method for a high frequency parallel connection of an inverter according to an embodiment of the present invention is provided.
  • the method is applied to achieve current sharing when the high-frequency parallel connection is performed at the output end of the multi-inverter, and the plurality of inverters include at least two inverters: a first inverter and a second inverter, and the first inverse
  • the outputs of the transformer and the second inverter are connected in parallel and inductive.
  • High-frequency parallel connection means that the frequency of the output voltage of each inverter connected in parallel is the same as the switching frequency of the inverter, generally several hundred Hz to several hundred kHz.
  • the high-frequency output voltage of the inverter is different from the power frequency output voltage of the inverter.
  • the high-frequency output voltage of the inverter is the same square wave as the inverter switching frequency, and the power frequency output voltage of the inverter is usually working. Frequency sine wave.
  • the high frequency harmonics are interference signals and need to be filtered out.
  • the high-frequency output voltage of the inverter is the same square wave as the inverter's own switching frequency. Therefore, the high-frequency signal is not an interference signal.
  • the applied inverter output should be inductive.
  • it can be realized by connecting an inductor at the output end of each inverter, and the inductiveness means that the phase of the output voltage of the inverter leads the phase of the inductor current.
  • the inductance of the inductor does not need to be too large, so that the output of the inverter is inductive.
  • the inductance here is different from the inductance that uses multiple inductors to achieve parallel current sharing.
  • the inductive reactance value of the inductor needs to be large enough to achieve the current sharing effect, and the method provided in this embodiment only needs to connect the inductor with a small inductive reactance value at the output end of the inverter. Inductors with smaller inductive reactance are smaller in size and lower in cost.
  • the current sharing method is applicable to an inverter in which two or more high-frequency output terminals are connected in parallel.
  • the output ends of the two inverters are connected in parallel as an example.
  • the current sharing method includes:
  • Step 101 Comparing the reactive current of the first inverter and the reactive current of the second inverter with the reactive current reference value, respectively obtaining the reactive current difference and the second inverse of the first inverter The reactive current difference of the transformer; Since the output terminals of each inverter are inductive, the reactive current output of each inverter can be adjusted by adjusting the input voltage amplitude of each inverter.
  • a current sensor such as a Hall element or a CT can be used to sample the output current of the inverter, and the active current and the reactive current are decomposed to obtain the reactive current output by each inverter, and the reactive current output by each inverter is The reactive current reference value is compared. It is also possible to perform sampling using the positional relationship between the reactive current and the output voltage.
  • the output current of each inverter is collected as the reactive current of each inverter.
  • the inverter output voltage is positive and negative, including the output voltage transition from positive to negative, and also includes the output voltage from negative to positive transition.
  • the current values corresponding to points 1 and 3 are the reactive current values output by the inverter.
  • the average value of the reactive current of each inverter can be calculated, and the average value of the reactive current is taken as the reactive current reference value.
  • a certain current value can be set as the reference value of the reactive current, and the method for determining the reference value of the reactive current is not limited herein.
  • the reactive current difference may be a difference obtained by subtracting the reactive current output from each inverter and the reactive current reference value.
  • Step 102 Comparing the active current of the first inverter and the active current of the second inverter with the active current reference value, respectively obtaining the active current difference of the first inverter and the active power of the second inverter Current difference
  • the active current outputted by each inverter can be adjusted by adjusting the phase difference between the self-carrier signal and the carrier synchronization signal of each inverter.
  • a current sensor such as a Hall element or a CT can be used to sample the inverter output current, and the active current and the reactive current are decomposed, and the active current output from each inverter is obtained, and the active current and the active power output from each inverter are obtained. Current reference values are compared. It is also possible to perform sampling using the positional relationship between the reactive current and the output voltage. Specifically, at the midpoint of the positive half cycle or the negative half cycle of each inverter output voltage, the output current of each inverter is collected as the active current of each inverter. As shown in Figure 2a, the current values corresponding to points 2 and 4 are the active current values of the inverter.
  • the average value of the active current of each inverter is obtained by using the active current of each inverter, and the average value of the active current can be used as the active current reference value.
  • a certain current value can be set as the active current reference value, and the method for determining the active current reference value is not limited herein.
  • the active current difference may be a difference obtained by subtracting the active current output from each inverter and the active current reference value.
  • Step 103 Adjusting the input voltage amplitudes of the first inverter and the second inverter according to the reactive current difference of the first inverter and the reactive current difference of the second inverter, respectively;
  • the active current difference of the first inverter and the active current difference of the second inverter respectively adjust a phase difference between a carrier signal generated by the first inverter and the second inverter and a carrier synchronization signal,
  • the current output of the first inverter and the output current of the second inverter are both currentized;
  • the carrier synchronization signal is a pulse signal input to the two inverters at the same time.
  • the input voltage amplitude of each inverter is adjusted, thereby adjusting the reactive current output by the inverter, so that the reactive current and reactive current reference values of the respective inverters are adjusted.
  • the difference is within the preset range, that is, the reactive current of each inverter is close to or equal to the reactive current reference value, so that the reactive current of each inverter reaches the current sharing.
  • the difference between the current and the active current reference value is within a preset range, that is, the active current of each inverter is close to or equal to the active current reference value, so that the active current of each inverter reaches a current sharing.
  • Steps 101 and 102 are two separate steps. Steps 101 and 102 are generally performed in synchronization with the sequence. That is, it is necessary to synchronously adjust the reactive current and the active current of each inverter to ensure that the reactive current and the active current of each inverter reach the current sharing at the same time, thereby ensuring that the current output by each inverter reaches the current sharing.
  • FIG. 2b the figure is a schematic diagram of the droop characteristic curve of the input voltage of the inverter and the reactive current of the inverter.
  • the horizontal axis is the reactive current
  • the vertical axis is the input voltage
  • the straight line indicates the droop characteristic of the input voltage and the reactive current.
  • the reactive current is I kq_set
  • the corresponding input voltage is U bus_set
  • the reactive current is I kq
  • the corresponding input voltage is U bus ; that is, different reactive currents correspond to different input voltages, but the input voltage and The reactive current satisfies the droop characteristic shown in Figure 2b.
  • FIG. 2c the figure is a schematic diagram of the phase difference between the synchronous carrier signal and the carrier signal of the inverter and the droop characteristic curve of the active current.
  • the horizontal axis represents the active current
  • the vertical axis represents the phase difference
  • the straight line represents the phase difference and the droop characteristic of the active current.
  • FIG. 3 a circuit diagram of a current sharing circuit is provided based on the current sharing method provided in this embodiment.
  • the current sharing circuit can be applied to the field of wireless charging to provide a large charging power for fast charging. It can also be used in the field of induction heating to provide greater power for fast heating.
  • the first to Nth inverters are all inverters, and the first to Nth inverters are connected in parallel, and one inductor is connected in series at each of the positive and negative outputs of each inverter to ensure the output of each inverter. The end is emotional.
  • the input terminals of the respective inverters are respectively connected to independent variable DC power sources to adjust the input voltage amplitude of each inverter.
  • the reactive current output of each inverter is adjusted by adjusting the input voltage amplitude of each inverter, so that the reactive current output by each inverter is equalized.
  • the active current output by the inverter can be adjusted by adjusting the phase difference between the carrier signal of each inverter and the carrier synchronization signal, so that the active current output by each inverter is currentized.
  • Each inverter is connected in parallel via an inductor to a positive common parallel point A and a negative common parallel point B, and the two ends of the latter device are respectively connected with a positive common parallel point A and a negative common parallel point B.
  • the post-stage device may be a transmitter compensation network, a transmitting coil, and the like to convert a high-frequency alternating current into an alternating magnetic field on the transmitting coil, and then convert the alternating magnetic field into another by electromagnetic induction.
  • the AC voltage or DC voltage to which the load is supplied for wireless charging.
  • the current sharing method provided in this embodiment adjusts the reactive current of the inverter by adjusting the amplitude of the input voltage of the inverter under the condition that the output end of the inverter is inductive, so that the output of each inverter is not
  • the work current is equalized;
  • the active current output by the inverter is adjusted by adjusting the phase difference between the carrier signal of each inverter and the carrier synchronization signal, so that the active current output by each inverter is equalized.
  • the reactive current and the active current output by each inverter are both currentized, so that the current output of each inverter can be equalized.
  • the current sharing method does not need to set a large number of large-scale hardware electronic devices in the circuit, and can ensure each inverse only by adjusting the input voltage amplitude of each inverter and the phase difference between the self-carrier signal and the carrier synchronization signal.
  • the current output of the transformer is currentized.
  • the method provided in this embodiment is applied to the inverter high frequency parallel, which is different from the inverter power frequency parallel connection.
  • photovoltaic grid-connected power generation belongs to the inverter power frequency parallel.
  • the pulse width modulation (PWM) technique is adopted, that is, the current sharing control is realized by adjusting the conduction pulse width of each bridge arm switch tube.
  • the current sharing of each inverter is not realized by adjusting the PWM, but the current sharing is realized by adjusting the DC bus voltage of each inverter and the phase difference between the carrier signal of each inverter and the carrier synchronization signal. control.
  • the method provided by the embodiment of the present application can achieve equal reactive currents of the respective inverters, and the active currents are also equal.
  • the reactive currents of the inverters are equal, the sharing of the total reactive power is achieved, so that the switching tubes of the respective inverters can achieve the effect of soft switching, thereby reducing the power consumption of the switching tubes and improving the power efficiency.
  • the current sharing method achieved by the embodiment of the present application achieves the effect of equalizing the output current of the inverter by adjusting the reactive current and the active current of the inverter to achieve current sharing.
  • the method of adjusting the reactive current and the method of adjusting the active current are described in detail below.
  • FIG. 4 it is a flowchart of a method for adjusting reactive current of an inverter provided by this embodiment.
  • the reactive current adjustment method is applicable to an inverter in which two or more high-frequency output terminals are connected in parallel.
  • the output ends of two inverters are connected in parallel as an example.
  • the current sharing method includes:
  • Step 401 Obtain a first voltage trimming amount according to a reactive current difference of the first inverter, and obtain a second voltage trimming amount according to a reactive current difference of the second inverter.
  • the reactive current difference of each inverter is correspondingly input to the reactive current regulator, and after being compensated by the reactive current regulator, the corresponding inverter is obtained.
  • the voltage trimming amount of the device is obtained.
  • Each inverter can be equipped with a reactive current regulator accordingly to obtain a voltage trimming amount corresponding to each inverter.
  • a reactive current regulator which is not limited herein.
  • Step 402 Superimposing the first voltage trimming amount and the first voltage adjusting amount setting value to obtain an input voltage reference value of the first inverter; and setting the second voltage trimming amount and the second voltage adjusting amount setting value Superimposed to obtain the input voltage reference value of the second inverter.
  • the voltage trimming amounts of the respective inverters obtained in step 401 are correspondingly superimposed with the voltage adjustment amount setting values of the respective inverters, thereby obtaining the input voltage reference values of the respective inverters.
  • the voltage adjustment amount setting value of each inverter is a preset value.
  • the voltage adjustment amount setting values of the respective inverters are set according to actual conditions.
  • the voltage adjustment amount setting values of the respective inverters can be set according to the power required by the load connected to the rear stage of the inverter. .
  • Step 403 Adjust the input voltage amplitude of the first inverter according to the input voltage reference value of the first inverter; adjust the input voltage of the second inverter according to the input voltage reference value of the second inverter. Amplitude.
  • the input voltage amplitudes of the respective inverters are adjusted accordingly.
  • variable DC power supply connected to each inverter can be adjusted, and the voltage amplitude outputted by each variable DC power supply is adjusted accordingly to the input voltage reference value obtained in step 402.
  • the reactive current reaches the reactive current reference value, or close to the reactive current reference value, that is, the reactive current equalization of each inverter output is realized.
  • FIG. 5 it is a schematic diagram of the reactive current adjustment process of the inverter.
  • the reactive current of the collected inverter is made to be different from the reactive current reference value, and the reactive current difference is obtained.
  • the reactive current difference is input to the reactive current regulator for processing, and the voltage trimming amount is obtained, and the voltage is finely adjusted.
  • the amount and the voltage adjustment amount set value are superimposed to obtain the input voltage reference value, and the input voltage amplitude of the inverter is adjusted according to the input voltage reference value, thereby realizing the regulation of the reactive current.
  • the reactive current adjustment method of the inverter provided in this embodiment can adjust the input voltage amplitude of each inverter to achieve the current sharing current of each inverter. Moreover, the reactive current outputted by each inverter reaches a current sharing, and each inverter can be in a soft switching (ZVS, Zero Voltage Switch) working state, and the switching loss of each inverter is reduced.
  • ZVS Zero Voltage Switch
  • the current sharing method is applicable to an inverter in which two or more high frequency output terminals are connected in parallel, for convenience of description, In this embodiment, the output ends of the two inverters are connected in parallel as an example.
  • the current sharing method includes:
  • Step 601 Obtain a first angle trimming amount according to the active current difference of the first inverter, and obtain a second angle trimming amount according to the active current difference of the second inverter.
  • the active current difference of each inverter After obtaining the active current difference of each inverter, the active current difference of each inverter is correspondingly input into the active current regulator, and after the compensation process by the active current regulator, the angle fine adjustment corresponding to different inverters is obtained. the amount.
  • each inverter can be equipped with an active current regulator correspondingly to obtain an angular fine adjustment amount corresponding to each inverter.
  • an active current regulator correspondingly to obtain an angular fine adjustment amount corresponding to each inverter.
  • Step 602 Superimposing the first angle trimming amount and the first angle adjusting amount setting value to obtain a first inverter self-carrier signal phase reference value; and setting the second angle trimming amount and the second angle adjusting amount setting value Phase superposition, obtaining the second inverter self-carrier signal phase reference value.
  • the angle trimming amounts of the respective inverters obtained in step 601 are correspondingly superimposed with the angle adjustment amount setting values of the respective inverters, thereby obtaining the respective carrier self-carrier signal phase reference values.
  • the angle adjustment amount setting value of each inverter is a preset angle value, and the angle adjustment amount setting value is specifically related to the power of the connected rear stage device, and if the connected rear stage device power changes, the angle adjustment The volume setting also needs to be changed accordingly.
  • the angle adjustment amount setting value may be 0.
  • the angle adjustment amount setting value may be set to any angle value according to an actual situation, and is not limited herein.
  • Step 603 Adjust a phase difference between the first inverter self-carrier signal and the carrier synchronization signal according to the first inverter self-carrier signal phase reference value; according to the second inverter self-carrier signal phase reference value, The phase difference between the second inverter self carrier signal and the carrier synchronization signal is adjusted.
  • the phase difference between each inverter's own carrier signal and the carrier synchronization signal is adjusted accordingly.
  • each carrier's own carrier signal can be adjusted such that the phase difference between each carrier's own carrier signal and the carrier synchronization signal is the carrier-specific carrier signal phase reference value.
  • phase difference between the carrier signal and the carrier synchronization signal of the inverter itself is proportional to the active current of the inverter
  • the difference between the active current and the active current reference value of each inverter is within a preset range, that is, the active current output by each inverter reaches or approaches the active current reference value, thereby realizing the active output of each inverter output. Current is equalized.
  • the phase of the inverter output voltage can represent the carrier's own carrier signal
  • the phase difference angle ⁇ between the phase of the output voltage and the carrier synchronization signal is the inverter's own carrier signal and carrier synchronization. The phase difference between the signals.
  • FIG. 7b it is a schematic diagram of an active current adjustment process for the inverter.
  • the active current of the collected inverter is compared with the active current reference value to obtain the active current difference, and the active current difference is input into the active current regulator for processing, and the angle fine adjustment amount is obtained.
  • the angle adjustment amount and the angle adjustment amount set value are superimposed to obtain a carrier signal phase reference value, and then the phase difference between the carrier self-carrier signal and the carrier synchronization signal is adjusted according to the carrier signal phase reference value, and further Realize the adjustment of the active current.
  • the active current adjustment method of the inverter provided in this embodiment can adjust the active current output by each inverter to achieve current sharing by adjusting the phase difference between the carrier signal of each inverter and the carrier synchronization signal.
  • the current of the parallel output of each inverter is adjusted to achieve the current sharing.
  • the embodiment of the present application further provides a current sharing device when the inverter is connected in high frequency, and the working principle is detailed in the following with reference to the accompanying drawings. Introduction.
  • FIG. 8a a structural diagram of a current sharing device when the inverter is connected in high frequency in parallel is provided.
  • the device is applied in parallel to at least the following two inverter high frequency outputs.
  • the two inverters include a first inverter 801 and a second inverter 802.
  • the current sharing device includes a first inverter controller 803, a second inverter controller 804, a first inductive component 805, and a second inductive component 806.
  • the current sharing device is applicable to an inverter in which two or more high-frequency output terminals are connected in parallel.
  • the output ends of the two inverters are connected in parallel as an example.
  • Each inverter is equipped with a corresponding inverter controller, and communication can be performed between each inverter controller.
  • each inverter may be the same, and the structure of each inverter controller may be the same.
  • the output end of the first inverter 801 is connected to the common parallel point through the first inductor component 805, the output end of the second inverter 802 is connected to the common parallel point through the second inductor component 806, and the first inductor component 805 makes the first inverter
  • the output of the second inverter component 806 renders the output of the second inverter inductive.
  • a post-stage device 807 is coupled to the first inductive component 805 and the second inductive component 806.
  • the post-stage device 807 can be a device for transmitting a compensation network, a transmit coil, or the like for charging a load.
  • the first inverter controller 803 is configured to compare the reactive current of the first inverter 801 with the reactive current reference value to obtain a reactive current difference of the first inverter 801, according to the first inverter
  • the reactive current difference of the 801 is used to adjust the input voltage amplitude of the first inverter 801; and is also used to compare the active current of the first inverter 801 with the active current reference value to obtain the first inverter 801.
  • the active current difference adjusts the phase difference between the carrier signal generated by the first inverter 801 and the carrier synchronization signal according to the active current difference of the first inverter 801.
  • the second inverter controller 804 is configured to compare the reactive current of the second inverter 802 with the reactive current reference value to obtain a reactive current difference of the second inverter 802, according to the second inverter
  • the reactive current difference of the 802 is used to adjust the input voltage amplitude of the second inverter 802; and is also used to compare the active current of the second inverter 802 with the active current reference value to obtain the second inverter 802.
  • the active current difference adjusts a phase difference between the carrier signal generated by the second inverter 802 and the carrier synchronization signal according to the active current difference of the second inverter 802.
  • the carrier synchronization signal is a pulse signal that is simultaneously input to the two inverters.
  • the first inverter 801 and the second inverter 802 may be an H-bridge inverter. As shown in FIG. 8b, the switch arms S1 and S2 form a bridge arm 1, and the switch tubes S3 and S4 form a bridge arm. 2, Uak is the midpoint voltage of the bridge arm 1, Ubk is the midpoint voltage of the bridge arm 2, and the difference between Uak and Ubk is the output voltage of the inverter. The output voltage of the inverter can be adjusted by adjusting the DC adjustable power supply Vdck.
  • the device shown in FIG. 8a is the device corresponding to the first embodiment of the method.
  • the specific method reference may be made to the description of the method embodiment 1, and details are not described herein again.
  • the current sharing device adjusts the reactive current of the inverter by adjusting the amplitude of the input voltage of the inverter under the condition that the output end of the inverter is inductive, so that the output of each inverter is not
  • the work current is equalized;
  • the active current output by the inverter is adjusted by adjusting the phase difference between the carrier signal of each inverter and the carrier synchronization signal, so that the active current output by each inverter is equalized.
  • the reactive current and the active current output by each inverter are both currentized, so that the current output of each inverter can be equalized.
  • each inverter can be ensured only by adjusting the input voltage amplitude of each inverter and the phase difference between the carrier signal and the carrier synchronization signal.
  • the output current is equalized.
  • the current sharing device provided by the above embodiment in the high frequency parallel connection of the inverter can select the host and the slave in a predetermined mechanism in the inverter controllers such as the first inverter controller and the second inverter controller. machine.
  • the carrier synchronization signal can be generated by the host and sent to the slave.
  • the host may be determined according to the order of power-on, that is, each inverter controller determines that the first power-on inverter controller is the master, and the other inverter controllers are slaves.
  • the host and the slave can also be selected according to other predetermined mechanisms, and no limitation is made herein.
  • the current sharing device After selecting the master and the slave, the current sharing device provided by the present application generally adopts the following two implementation manners to determine and send the reactive current reference value and the active current reference value to the respective inverter controllers.
  • the host determines the reactive current reference value and the active current reference value of the current sharing device, and the host sends the reactive current reference value and the active current reference value to the respective slaves.
  • the host and each slave determine the reactive current reference value and the active current reference value of the current sharing device, and the host and each slave directly use the reactive current reference value and the active current reference value determined by themselves. .
  • the current sharing device in the following embodiments is applicable to an inverter in which two or more high frequency output terminals are connected in parallel.
  • the output of two inverters is used in the following embodiments. The ends are connected in parallel as an example.
  • Each inverter is equipped with a corresponding inverter controller, and communication can be performed between each inverter controller.
  • the current sharing device in the following embodiments assumes that the first inverter controller is the master and the other inverter controllers are the slaves.
  • FIG. 9 is a structural diagram of another current sharing device when the inverter is connected in high frequency in parallel according to the embodiment.
  • the current sharing device includes, in addition to the components included in the first embodiment, a first reactive current sampling circuit 901, a first active current sampling circuit 902, a second reactive current sampling circuit 903, and a second active current sampling circuit. 904.
  • the first reactive current sampling circuit 901 is configured to obtain a reactive current of the first inverter 801.
  • the first active current sampling circuit 902 is configured to obtain an active current of the first inverter 801.
  • the second reactive current sampling circuit 903 is configured to obtain a reactive current of the second inverter 802.
  • the second active current sampling circuit 904 is configured to obtain an active current of the second inverter 802.
  • the reactive current reference value is sent to the slave machine; and is used to obtain an active current average value from the active current of the first inverter 801 and the active current of the second inverter 802, and the active current average value is used as the active power
  • a current reference value and an active current reference value is sent to the slave.
  • the first inverter controller 803 is a host, and the host transmits a carrier synchronization signal to the carrier synchronization signal bus, and the carrier synchronization signal bus transmits the carrier synchronization signal to the other slaves.
  • the first reactive current sampling circuit 901 collects the reactive current of the first inverter, and sends the collected reactive current of the first inverter to the first inverter controller 803;
  • the first active current sampling circuit 902 collects the active current of the first inverter, and sends the collected active current of the first inverter to the first inverter controller 803.
  • the first reactive current sampling circuit 901 and the first active current sampling circuit 902 can both collect the reactive current and the active current of the first inverter from the positive output end of the first inverter;
  • the negative output end of the inverter collects the reactive current and the active current of the first inverter; and the first inverse is also collected from the positive output end of the first inverter and the negative output end of the first inverter respectively
  • the reactive current and the active current of the transformer do not limit the position of the current collected by the first reactive current sampling circuit and the first active current sampling circuit.
  • the first inverter controller 803 transmits the reactive current and the active current of the first inverter to the wired communication bus.
  • the working modes of the other inverter modules in collecting and transmitting the reactive current and the active current are the same as those in the first inverter module, and are not described here.
  • the first inverter controller 803 acts as a host, collects reactive current and active current sent by each inverter to the wired communication bus, calculates an average value of the reactive current according to the reactive current sent by each inverter, and The average value of the reactive current is used as the reference value of the reactive current; the average value of the active current is calculated according to the active current sent by each inverter, and the average value of the active current is used as the reference value of the active current.
  • the first inverter controller 803 sends the reactive current reference value and the active current reference value to the wired communication bus, and sends the reactive current reference value and the active current reference value to each inverter control by the wired communication bus. Device.
  • the other inverter controller acts as a slave, receives the reactive current reference value and the active current reference value sent by the host to the wired communication bus, and adjusts the reactive power of each inverter according to the reactive current reference value and the active current reference value. Current and active current.
  • the host and the slave are determined in each inverter controller, and the carrier synchronization signal is sent by the host, and the reactive current reference value and the active current reference value of the current sharing device are determined by the host.
  • the reactive current of the inverter is adjusted by adjusting the amplitude of the input voltage of the inverter, so that the reactive current output by each inverter is equalized;
  • the phase difference between the carrier's own carrier signal and the carrier synchronization signal adjusts the active current output by the inverter so that the active current output by each inverter flows.
  • the reactive current and the active current output by each inverter are both currentized, so that the current output of each inverter can be equalized.
  • each inverter can be ensured only by adjusting the input voltage amplitude of each inverter and the phase difference between the carrier signal and the carrier synchronization signal.
  • the output current is equalized.
  • the current sharing device in the second implementation is described below.
  • FIG. 10 it is a structural diagram of a current sharing device when the inverter is connected in high frequency in parallel according to the embodiment.
  • the current sharing device includes, in addition to the components included in the first embodiment, a first reactive current sampling circuit 1001, a first active current sampling circuit 1002, a second reactive current sampling circuit 1003, and a second active current sampling circuit. 1004.
  • the first reactive current sampling circuit 1001 is configured to obtain a reactive current of the first inverter.
  • the first active current sampling circuit 1002 is configured to obtain an active current of the first inverter.
  • the second reactive current sampling circuit 1003 is configured to obtain a reactive current of the second inverter.
  • the second active current sampling circuit 1004 is configured to obtain an active current of the second inverter.
  • the first inverter controller 801 is configured to obtain an average value of the reactive current from the reactive current of the first inverter 801 and the reactive current of the second inverter 802, and use the average value of the reactive current as the reactive current
  • the reference value is also used to obtain an active current average value from the active current of the first inverter 801 and the active current of the second inverter 802, and the average value of the active current is used as the active current reference value.
  • the second inverter controller 802 is configured to obtain an average value of the reactive current from the reactive current of the first inverter 801 and the reactive current of the second inverter 802, and use the average value of the reactive current as the
  • the working current reference value is also used to obtain an active current average value from the active current of the first inverter 801 and the active current of the second inverter 802, and the average value of the active current is used as the active current reference value.
  • the first inverter controller 803 is a host, and the host sends a carrier synchronization signal to the carrier synchronization signal bus, and the carrier synchronization signal bus transmits the carrier synchronization signal to other slaves.
  • the first reactive current sampling circuit 1001 collects the reactive current of the first inverter, and transmits the collected reactive current of the first inverter to the first inverter controller 803;
  • the first active current sampling circuit 1002 collects the active current of the first inverter, and sends the collected active current of the first inverter to the first inverter controller 803.
  • the first reactive current sampling circuit 1001 and the first active current sampling circuit 1002 can both collect the reactive current and the active current of the first inverter from the positive output end of the first inverter;
  • the negative output end of the inverter collects the reactive current and the active current of the first inverter; and the first inverse is also collected from the positive output end of the first inverter and the negative output end of the first inverter respectively
  • the reactive current and the active current of the transformer do not limit the position of the current collected by the first reactive current sampling circuit and the first active current sampling circuit.
  • the first inverter controller 803 transmits the reactive current and the active current of the first inverter to the wired communication bus.
  • the other inverter module works in the same way as the first inverter module, and the reactive current of the inverter is collected by the corresponding reactive current sampling circuit, and the reactive current is sent to the corresponding inverter controller;
  • the active current sampling circuit collects the active current of the inverter and sends the active current to the corresponding inverter controller.
  • the inverter current and the active current of each inverter are then sent to the wired communication bus by the respective inverter controllers.
  • Each inverter controller collects the reactive current sent by each inverter controller on the wired communication bus, and calculates the average value of the reactive current according to each reactive current, and takes the average value of the reactive current as reactive power. Current reference value. Further, according to the reactive current reference value, the reactive current of the corresponding inverter is adjusted such that the difference between the reactive current and the reactive current reference value of the inverter is within a preset range.
  • Each inverter controller collects the active current sent by each inverter controller on the wired communication bus, and calculates an average value of the active current according to each active current, and takes the average value of the active current as the active current reference value. Further, according to the active current reference value, the active current of the corresponding inverter is adjusted such that the difference between the active current and the active current reference value of the inverter is within a preset range.
  • the master and the slave are determined in each inverter controller, and the carrier synchronization signal is sent by the host. Both the master and the slave receive the reactive current and active current of each inverter on the wired communication bus. Both the master and the slave calculate the reactive current reference value and the active current reference according to the reactive current and active current of each inverter. value.
  • the reactive current of the inverter is adjusted by adjusting the amplitude of the input voltage of the inverter, so that the reactive current output by each inverter is equalized;
  • the phase difference between the carrier's own carrier signal and the carrier synchronization signal adjusts the active current output by the inverter so that the active current output by each inverter flows.
  • the reactive current and the active current output by each inverter are both currentized, so that the current output of each inverter can be equalized.
  • each inverter can be ensured only by adjusting the input voltage amplitude of each inverter and the phase difference between the carrier signal and the carrier synchronization signal.
  • the output current is equalized.
  • the embodiment of the present application further provides an inverter system for the high frequency parallel connection of the inverter, and the working principle thereof is described below with reference to the accompanying drawings. detailed introduction.
  • FIG. 11 a structural diagram of an inverter system in which a high frequency parallel connection of an inverter is provided is provided in this embodiment.
  • the system includes the current sharing device in the above device embodiment, and further includes at least two inverter high frequency output terminals connected in parallel: a first inverter 801 and a second inverter 802.
  • the input end of the first inverter 801 is connected to the first adjustable power source Vdc1.
  • the input of the second inverter 802 is connected to the second adjustable power source Vdc2.
  • the input voltage amplitude of the inverter is adjusted, thereby adjusting the reactive current of the inverter, so that the reactive current output by each inverter is flow.
  • the inverter system provided in this embodiment is applied to a structural diagram in the field of wireless charging.
  • Each inverter is connected in parallel to the positive common parallel point A and the negative common parallel point B.
  • Each inverter converts the DC voltage input from the adjustable power source into a high frequency alternating current voltage, and the high frequency alternating current voltage passes through the transmitting end compensation network 1101.
  • An alternating current is generated on the transmitting coil, and the alternating current produces an alternating magnetic field.
  • the receiving coil induces an alternating voltage at both ends of the receiving coil through electromagnetic induction, and the receiving end compensates the network 1102 and the rectifying and filtering circuit 1103 to convert the induced alternating current voltage into a direct current voltage required by the load.
  • the inverter system adjusts the reactive current of the inverter by adjusting the amplitude of the input voltage of the inverter under the condition that the output end of the inverter is inductive, so that the output of each inverter is not
  • the work current is equalized;
  • the active current output by the inverter is adjusted by adjusting the phase difference between the carrier signal of each inverter and the carrier synchronization signal, so that the active current output by each inverter is equalized.
  • the reactive current and the active current output by each inverter are both currentized, so that the current output of each inverter can be equalized.
  • each inverter can be ensured only by adjusting the input voltage amplitude of each inverter and the phase difference between the self-carrier signal and the carrier synchronization signal.
  • the output current is equalized.
  • the adjustable power supply in the inverter system provided in the first embodiment of the system may be a DC adjustable power supply or an AC adjustable power supply.
  • the rectifier is required to rectify the AC to DC and provide the inverter. The input of the device.
  • the adjustable power supply is a DC adjustable power supply.
  • FIG. 12 a structural diagram of another inverter system provided in this embodiment is shown.
  • the adjustable power supply in the system is a DC adjustable power supply.
  • the first DC-DC converter 1201 connected to the first inverter 801 is shown in FIG. 12, and the first A DC adjustable power supply Vdc1.
  • the DC-DC converter connected to the remaining inverters can be the same as the first DC-DC converter, and the remaining DC adjustable power supplies can also be the same as the first DC adjustable power supply.
  • the first DC-DC converter 1201 is configured to convert the voltage outputted by the first DC adjustable power supply Vdc1 to the input end of the first inverter.
  • the output voltage of the remaining DC adjustable power supply is converted by the DC-DC converter corresponding thereto to output the voltage of the DC adjustable power supply.
  • the DC-DC converter may be a Boost boost circuit, a Buck step-down circuit, or a Boost-Buck buck-boost circuit, and the type of the DC-DC converter is not limited herein.
  • the DC adjustable power supply can also be composed of two DC adjustable power supplies connected in series, as shown in FIG. 13, the first DC adjustable power supply is composed of a DC adjustable power supply Vdc1u and a DC adjustable power supply Vdc1d connected in series.
  • the input voltage amplitude of each inverter can be adjusted by adjusting each DC adjustable power supply and each DC-DC converter, and then The reactive current output of each inverter is adjusted to achieve current sharing. Then, the phase difference between each carrier's own carrier signal and the carrier synchronization signal is adjusted to adjust the active current output by the inverter, so that the active current output by each inverter is currentized.
  • the reactive current and the active current output by each inverter are both currentized, so that the current output of each inverter can be equalized.
  • the adjustable power supply is an AC adjustable power supply.
  • FIG. 14 a structural diagram of still another inverter system according to the embodiment is shown.
  • the adjustable power supply in the system is an AC adjustable power supply.
  • first AC-DC converter 1401 connected to the first inverter 801 is shown in FIG. 14 and the first AC adjustable power supply Vin1.
  • the AC-DC converter connected to the remaining inverters can be the same as the first AC-DC converter, and the remaining AC adjustable power supplies can also be the same as the first AC adjustable power supply.
  • the first AC-DC converter 1401 is configured to rectify the first AC adjustable power supply Vin1 to DC power and then to the input end of the first inverter.
  • the voltage output of the remaining AC adjustable power supply is processed by the corresponding AC-DC converter to convert the voltage outputted by the AC adjustable power supply.
  • a Power Factor Correction (PFC) circuit 1501 can be used to convert the AC voltage in the power grid into a DC voltage.
  • the PFC circuit includes a rectifier circuit
  • the power grid can be The AC voltage in the rectifier is rectified to a DC voltage.
  • the DC voltage is adjusted by the DC-DC converter 1502 as the input voltage of the inverter, thereby adjusting the reactive current output by the inverter.
  • the function of adjusting the input voltage of the inverter can also be realized by setting only the PFC circuit in the system.
  • the command issued by the inverter controller is sent to the PFC circuit 1501, according to which the PFC circuit 1501 converts the AC voltage in the power grid into the required DC voltage, and uses the DC voltage as an inverter.
  • the input voltage of the device achieves the purpose of regulating the reactive current.
  • the input voltage amplitude of each inverter can be adjusted by adjusting each AC adjustable power supply and each AC-DC converter, and then The reactive current output of each inverter is adjusted to achieve current sharing. Then, the phase difference between each carrier's own carrier signal and the carrier synchronization signal is adjusted to adjust the active current output by the inverter, so that the active current output by each inverter is currentized.
  • the reactive current and the active current output by each inverter are both currentized, so that the current output of each inverter can be equalized.
  • the embodiment of the present application further provides a wireless charging system, for example, when used for charging an electric vehicle, the load may be a battery of the electric vehicle.
  • the load may be a battery of the electric vehicle.
  • the wireless charging system provided in this embodiment includes the current sharing device in the above embodiment, and further includes at least two inverter high frequency output terminals connected in parallel: a first inverter and a second inverter; and further includes: An adjustable power source, a second adjustable power source, a wireless transmitting circuit and a wireless receiving circuit;
  • the input end of the first inverter is connected to the first adjustable power source
  • the input end of the second inverter is connected to the second adjustable power source
  • An output end of the first inverter is connected to an input end of the wireless transmitting circuit
  • An output end of the second inverter is connected to an input end of the wireless transmitting circuit
  • the wireless transmitting circuit transmits power through a wireless manner, and the wireless receiving circuit wirelessly receives power transmitted by the wireless transmitting circuit to supply power to the load.
  • the wireless transmitting circuit includes a transmitting compensation network and a transmitting coil;
  • the wireless receiving circuit includes a receiving compensation network and a receiving coil;
  • An input end of the transmission compensation network is used as an input end of the wireless transmission circuit, and an output end of the transmission compensation network is connected to the transmitting coil;
  • a receiving coil is coupled to the input of the receiving compensation network, and an output of the receiving compensation network is coupled to the load.
  • the inverter system provided by the above embodiments can also be applied to the field of induction heating, in which case the load can be a device requiring heating, for example, various profiles require heating to melt or deform. Specifically, it may be casting of an aluminum device or the like.

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Abstract

本申请公开了一种逆变器的均流方法、装置、逆变系统及无线充电系统，用于实现多逆变器均流，方法包括：将第一逆变器的无功电流和第二逆变器的无功电流分别与无功电流参考值进行比较，分别获得第一逆变器和第二逆变器的无功电流差值；将第一逆变器和第二逆变器的有功电流分别与有功电流参考值进行比较，分别获得第一逆变器和第二逆变器的有功电流差值；根据第一逆变器和第二逆变器的无功电流差值分别调节第一逆变器和第二逆变器的输入电压幅值，根据第一逆变器和第二逆变器的有功电流差值分别调节第一逆变器和第二逆变器自身产生的载波信号与载波同步信号之间的相位差，以使两个逆变器的输出电流实现均流。

Description

逆变器的均流方法、装置、逆变系统及无线充电系统
本申请要求于2017年10月24日提交中国专利局、申请号为201711000947.2、申请名称为“逆变器的均流方法、装置、逆变系统及无线充电系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电力电子技术领域，尤其涉及一种逆变器的均流方法、装置、逆变系统及无线充电系统。
背景技术
随着能源的枯竭以及环境污染越来越严重，新能源汽车的应用越来越普及，例如电动汽车。但是，电动汽车的充电问题成为急需解决的问题，目前有线充电桩的发展非常快，但是充电面临的一个问题是小功率充电的时间比较长，如果电动汽车充电能够像燃油汽车加油那么快必须要提高充电功率。所以有线充电已经向350kW、500kW的方向发展。
但是，有线充电面临的问题是有线充电需要操作人员手动插拔充电枪，在雷雨天有被电击的危险。
另外，电动汽车的电池电压范围确定后，充电功率越大则充电枪的充电线缆就越粗越笨重，甚至导致人工拿不动充电线缆，而需要机械装置来辅助操作。另外经常插拔线缆很容易损坏，造成维护成本高。
为了解决有线充电存在的以上问题，无线充电技术应运而生。
无线充电的供电电源和负载之间没有电气连接，不需要充电枪。而且充电自动进行，充电过程安全、方便。
但是，无线充电和有线充电面临相同的问题，就是无线充电同样需要向快充的方向发展。在无线充电系统向高功率方向发展的过程中，有单机结构和多机并联结构。
当采用多个高频模块并联的模式进行供电时，高频模块间的并联可能由于每个并联模块的参数差异、驱动延时等原因造成每个并联模块的输出电流不均，有的模块输出电流大，有的输出电流小，由此导致逆变器间的发热不一致，严重时甚至导致炸机。
传统技术是通过预留更大的设计裕度，使发热最严重的模块也能满足温升的要求，但是太大的冗余设计会导致系统的功率密度降低，可靠性降低。
发明内容
本申请提供了一种逆变器的均流方法、装置、逆变系统及无线充电系统，能够实现逆变器输出电流的均流，而且可靠性高。
第一方面，提供一种逆变器的均流方法，用于在多逆变器的输出端高频并联时实现均流，所述多逆变器至少包括两个逆变器：第一逆变器和第二逆变器；所述第一逆变器和第二逆变器的输出端相互并联并呈感性，所述方法包括：
将所述第一逆变器的无功电流和所述第二逆变器的无功电流分别与无功电流参考值进行比较，分别获得第一逆变器的无功电流差值和第二逆变器的无功电流差值；
将所述第一逆变器的有功电流和第二逆变器的有功电流分别与有功电流参考值进行比较，分别获得第一逆变器的无功电流差值和第二逆变器的有功电流差值；
根据所述第一逆变器无功电流差值和第二逆变器的无功电流差值分别调节第一逆变器和第二逆变器的输入电压幅值，根据所述第一逆变器有功电流差值和第二逆变器的有功电流差值分别调节第一逆变器和第二逆变器自身产生的载波信号与载波同步信号之间的相位差，以使所述第一逆变器的输出电流与所述第二逆变器的输出电流实现均流，所述载波同步信号为同时对所述两个逆变器同时输入的脉冲信号。
在逆变器的输出端呈感性的条件下，通过调节逆变器输入电压幅值，调节逆变器输出的无功电流，使得各个逆变器输出的无功电流均流；通过调节各个逆变器自身载波信号与载波同步信号之间的相位差，调节逆变器输出的有功电流，使得各个逆变器输出的有功电流均流。
在第一方面的第一种可能的实现方式中，根据第一逆变器的无功电流差值调节第一逆变器的输入电压幅值，具体包括：
根据第一逆变器的无功电流差值获得第一电压微调量；
将所述第一电压微调量与第一电压调节量设定值相叠加获得第一逆变器的输入电压给定值；
根据所述第一逆变器的输入电压给定值调节所述第一逆变器的输入电压幅值；
根据第二逆变器的无功电流差值调节第二逆变器的输入电压幅值，具体包括：
根据第二逆变器的无功电流差值获得第二电压微调量；
将所述第二电压微调量与第二电压调节量设定值相叠加获得第二逆变器的输入电压给定值；
根据所述第二逆变器的输入电压给定值调节所述第二逆变器的输入电压幅值。
结合第一方面及上述任一种可能的实现方式中，在第二种可能的实现方式中，根据第一逆变器的有功电流差值调节第一逆变器自身载波信号与载波同步信号之间的相位差，具体包括：
根据所述第一逆变器的有功电流差值获得第一角度微调量；
将所述第一角度微调量与第一角度调节量设定值相叠加获得第一逆变器自身载波信号相位给定值；
根据所述第一逆变器自身载波信号相位给定值调节第一逆变器自身载波信号与载波同步信号之间的相位差；
根据第二逆变器的有功电流差值调节第二逆变器自身载波信号与所述载波同步信号之间的相位差，具体包括：
根据所述第二逆变器的有功电流差值获得第二角度微调量；
将所述第二角度微调量与第二角度调节量设定值相叠加获得第二逆变器自身载波信号相位给定值；
根据所述第二逆变器自身载波信号相位给定值调节第二逆变器自身载波信号与载波同步信号之间的相位差。
将采集的逆变器的无功电流与无功电流参考值做差，得到无功电流差值，将该无功电流差值输入无功电流调节器进行处理，得到电压微调量，将电压微调量与电压调节量设定值进行叠加，即可得到输入电压给定值，根据该输入电压给定值，调节逆变器的输入电压幅值，进而实现无功电流的调节。
本实施例提供的逆变器的无功电流调节方法，能够通过调节各个逆变器的输入电压幅值，使得各个逆变器输出的无功电流达到均流。并且，各个逆变器输出的无功电流达到均流，还可以使得各个逆变器处于软开关(ZVS，Zero Voltage Switch)工作状态，降低各个逆变器的开关损耗。
结合第一方面及上述任一种可能的实现方式中，在第三种可能的实现方式中，所述获得所述第一逆变器的有功电流和第二逆变器的有功电流，具体包括：
在第一逆变器输出电压正半周期或负半周期的中点时刻采集第一逆变器输出电流为所述第一逆变器的有功电流；在第二逆变器输出电压正半周期或负半周期的中点时刻采集第二逆变器输出电流为所述第二逆变器的有功电流；
所述获得所述第一逆变器的无功电流和第二逆变器的无功电流，具体包括：
在第一逆变器输出电压正负跳变时刻采集第一逆变器输出电流为所述第一逆变器的无功电流；在第二逆变器输出电压正负跳变时刻采集第二逆变器输出电流为所述第二逆变器的无功电流。
将采集的逆变器的有功电流与有功电流参考值做差，得到有功电流差值，将该有功电流差值输入有功电流调节器进行处理，得到角度微调量。将角度微调量与角度调节量设定值进行叠加，即可得到载波信号相位给定值，进而根据该载波信号相位给定值，调节逆变器自身载波信号与载波同步信号的相位差，进而实现有功电流的调节。
结合第一方面及上述任一种可能的实现方式中，在第四种可能的实现方式中，所述第一逆变器和第二逆变器的输出电压并联在一起，且所述输出电压的频率与所述第一逆变器和第二逆变器的开关频率相同。
结合第一方面及上述任一种可能的实现方式中，在第五种可能的实现方式中，所述无功电流参考值为所述第一逆变器的无功电流和第二逆变器的无功电流的平均值，所述有功电流参考值为所述第一逆变器的有功电流和第二逆变器的有功电流的平均值。
第二方面，提供一种逆变器均流装置，用于在多逆变器的输出端高频并联时实现均流，所述多逆变器至少包括两个逆变器：第一逆变器和第二逆变器；所述第一逆变器和第二逆变器的输出端相互并联并呈感性，
该均流装置包括：第一逆变器控制器、第二逆变器控制器、第一电感组件和第二电感组件；
所述第一逆变器的输出端通过所述第一电感组件连接公共并联点，所述第二逆变器的输出端通过所述第二电感组件连接公共并联点，所述第一电感组件使所述第一逆变器的输出端呈现感性，所述第二电感组件使所述第二逆变器的输出端呈现感性；
所述第一逆变器控制器，用于将所述第一逆变器的无功电流与无功电流参考值进行比较，获得第一逆变器的无功电流差值，根据第一逆变器的无功电流差值调节第一逆变器的输入电压幅值；还用于将所述第一逆变器的有功电流与有功电流参考值进行比较，获得第一逆变器的有功电流差值，根据第一逆变器的有功电流差值调节第一逆变器自身产生的载波信号与载波同步信号之间的相位差；所述载波同步信号为同时对所述两个逆变器同时输入的脉冲信号；
所述第二逆变器控制器，用于将所述第二逆变器的无功电流与无功电流参考值进行比较，获得第二逆变器的无功电流差值，根据第二逆变器的无功电流差值调节第二逆变器的输入电压幅值；还用于将所述第二逆变器的有功电流与有功电流参考值进行比较，获得第二逆变器的有功电流差值，根据第二逆变器的有功电流差值调节第二逆变器自身产生的载波信号与所述载波同步信号之间的相位差。
在逆变器的输出端呈感性的条件下，通过调节逆变器输入电压幅值，调节逆变器输出的无功电流，使得各逆变器输出的无功电流均流；通过调节各个逆变器自身载波信号与载波同步信号之间的相位差，调节逆变器输出的有功电流，使得各逆变器输出的有功电流均流。各逆变器输出的无功电流和有功电流都实现均流，即可保证各逆变器输出的电流均流。该均流装置中无需设置较多体积较大的硬件电子器件，仅通过调节各逆变器输入电压幅值，以及自身载波信号与载波同步信号之间的相位差，即可保证各个逆变器输出的电流均流。
上述实施例提供的逆变器高频并联时的均流装置，可以在第一逆变器控制器和第二逆变器控制器等逆变器控制器中，以预定机制选择出主机和从机。载波同步信号可以由主机产生，并将其发送给从机。
在第二方面的第一种可能的实现方式中，所述第一逆变器控制器和第二逆变器控制器以预定机制选择出主机和从机；
所述载波同步信号由所述主机产生，并发送给所述从机。
结合第二方面及上述任一种可能的实现方式中，在第二种可能的实现方式中，还包括：第一无功电流采样电路、第一有功电流采样电路、第二无功电流采样电路和第二有功电流采样电路；
所述第一无功电流采样电路，用于获得所述第一逆变器的无功电流；
所述第一有功电流采样电路，用于获得所述第一逆变器的有功电流；
所述第二无功电流采样电路，用于获得所述第二逆变器的无功电流；
所述第二有功电流采样电路，用于获得所述第二逆变器的有功电流；
所述主机，用于由所述第一逆变器的无功电流和第二逆变器的无功电流获得无功电流平均值，将所述无功电流平均值作为所述无功电流参考值，并将所述无功电流参考值发送给所述从机；还用于由所述第一逆变器的有功电流和第二逆变器的有功电流获得有功电流平均值，将所述有功电流平均值作为所述有功电流参考值，并将所述有功电流参考值发送给所述从机。
结合第二方面及上述任一种可能的实现方式中，在第三种可能的实现方式中，还包括：第一无功电流采样电路、第一有功电流采样电路、第二无功电流采样电路和第二有功电流 采样电路；
所述第一无功电流采样电路，用于获得所述第一逆变器的无功电流；
所述第一有功电流采样电路，用于获得所述第一逆变器的有功电流；
所述第二无功电流采样电路，用于获得所述第二逆变器的无功电流；
所述第二有功电流采样电路，用于获得所述第二逆变器的有功电流；
所述第一逆变器控制器，用于由所述第一逆变器的无功电流和第二逆变器的无功电流获得无功电流平均值，将所述无功电流平均值作为所述无功电流参考值；还用于由所述第一逆变器的有功电流和第二逆变器的有功电流获得有功电流平均值，将所述有功电流平均值作为所述有功电流参考值；
所述第二逆变器控制器，用于由所述第一逆变器的无功电流和第二逆变器的无功电流获得无功电流平均值，将所述无功电流平均值作为所述无功电流参考值；还用于由所述第一逆变器的有功电流和第二逆变器的有功电流获得有功电流平均值，将所述有功电流平均值作为所述有功电流参考值。
第三方面，提供一种逆变系统，包括所述的均流装置，还至少包括以下两个逆变器：第一逆变器和第二逆变器；
所述第一逆变器的输入端连接第一可调电源；
所述第二逆变器的输入端连接第二可调电源。
在第三方面的第一种可能的实现方式中，还包括：第一直流-直流变换器和第二直流-直流变换器；
所述第一可调电源为第一直流可调电源，所述第二可调电源为第二直流可调电源；
所述第一直流-直流变换器，用于将所述第一直流可调电源输出的电压进行转换后输送给所述第一逆变器的输入端；
所述第二直流-直流变换器，用于将所述第二直流可调电源输出的电压进行转换后输送给所述第二逆变器的输入端；
结合第三方面及上述任一种可能的实现方式中，在第二种可能的实现方式中，还包括：第一交流-直流变换器和第二交流-直流变换器；
所述第一可调电源为第一交流可调电源，所述第二可调电源为第二交流可调电源；
所述第一交流-直流变换器，用于将所述第一交流可调电源整流为直流电后输送给所述第一逆变器的输入端；
所述第二交流-直流变换器，用于将所述第二交流可调电源整流为直流电后输送给所述第二逆变器的输入端。
第四方面，提供一种无线充电系统，包括所述的均流装置，还包括至少以下两个逆变器：第一逆变器和第二逆变器；
还包括：第一可调电源、第二可调电源、无线发射电路和无线接收电路；
所述第一逆变器的输入端连接第一可调电源；
所述第二逆变器的输入端连接第二可调电源；
所述第一逆变器的输出端连接所述无线发射电路的输入端；
所述第二逆变器的输出端连接所述无线发射电路的输入端；
所述无线发射电路通过无线方式将电能发射出去，所述无线接收电路通过无线方式接收所述无线发射电路发射的电能以给负载供电。
以上实施例提供的均流装置还可以应用于感应加热领域，此时负载可以为需要加热的设备，例如各种型材需要加热融化或变形。具体可以为铝质设备的铸造等。
在第四方面的第一种可能的实现方式中，所述无线发射电路包括发射补偿网络和发射线圈；所述无线接收电路包括接收补偿网络和接收线圈；
所述发射补偿网络的输入端作为所述无线发射电路的输入端，所述发射补偿网络的输出端连接所述发射线圈；
所述接收线圈连接所述接收补偿网络的输入端，所述接收补偿网络的输出端连接负载。
从以上技术方案可以看出，本申请实施例具有以下优点：
该方法应用于至少两个逆变器高频输出端并联的情况，并且各个逆变器输出端呈感性。具体实现时，将各个逆变器的无功电流与无功电流参考值进行比较，获得各个逆变器的无功电流差值，根据各个逆变器的无功电流差值相应地调节各个逆变器输入电压幅值；将各个逆变器的有功电流与有功电流参考值进行比较，获得各个逆变器的有功电流差值，根据各个逆变器的有功电流差值，调节各个逆变器自身的载波信号与载波同步信号之间的相位差，其中，载波同步信号为给定信号。
本申请实施例提供的均流方法，在逆变器的输出端呈感性的条件下，通过调节逆变器输入电压幅值，调节逆变器输出的无功电流，使得各个逆变器输出的无功电流均流；通过调节各个逆变器自身载波信号与载波同步信号之间的相位差，调节逆变器输出的有功电流，使得各个逆变器输出的有功电流均流。各个逆变器输出的无功电流和有功电流都实现均流，即可保证各个逆变器输出的电流均流。该均流方法无需在电路中设置较多体积较大的硬件电子器件，仅通过调节各逆变器输入电压幅值，以及自身载波信号与载波同步信号之间的相位差，即可保证各个逆变器输出的电流均流。
附图说明
图1为本申请方法实施例一提供的一种逆变器高频并联时的均流方法的流程图；
图2a为逆变器输出电流和逆变器输出电压的波形图；
图2b为逆变器的输入电压与逆变器的无功电流的下垂特性曲线示意图；
图2c为同步载波信号与逆变器的载波信号的相位差与有功电流的下垂特性曲线示意图；
图3为本申请实施例提供的一种均流电路的电路图；
图4为本申请方法实施例二提供的逆变器的无功电流调节方法的流程图；
图5为本申请方法实施例二提供的逆变器的无功电流调节过程的示意图；
图6为本申请方法实施例三提供的逆变器的有功电流调节方法的流程图；
图7a为逆变器输出电压与载波同步信号的波形图；
图7b为本申请方法实施例三提供的逆变器的有功电流调节过程的示意图；
图8a为本申请装置实施例一提供的一种逆变器高频并联时的均流装置的结构图；
图8b为H桥逆变器的结构图；
图9为本申请装置实施例二提供的一种逆变器高频并联时的均流装置的结构图；
图10为本申请装置实施例三提供的一种逆变器高频并联时的均流装置的结构图；
图11为本申请系统实施例一提供的一种逆变器高频并联时的逆变系统的结构图；
图12为本申请系统实施例二提供的一种逆变器高频并联时的逆变系统的结构图；
图13为本申请系统实施例二提供的另一种逆变器高频并联时的逆变系统的结构图；
图14为本申请系统实施例三提供的一种逆变器高频并联时的逆变系统的结构图；
图15为本申请系统实施例三提供的另一种逆变器高频并联时的逆变系统的结构图；
图16为本申请系统实施例三提供的又一种逆变器高频并联时的逆变系统的结构图。
具体实施方式
本申请实施例提供了一种逆变器的均流方法，用于保证输出端并联的各个逆变器之间实现均流。
随着电动汽车的普及，电动汽车的充电问题越来越受关注。目前主要利用有线充电桩对电动汽车进行充电。然而，有线充电桩的充电功率较小，利用其对电动汽车进行充电往往需要较长的时间。若要实现电动汽车的快速充电，则需要提高有线充电桩的充电功率。而提高有线充电桩的充电功率，则会出现背景技术中所介绍的人工无法拿动充电线缆以及充电线缆的维护成本提高等技术问题。
为了解决上述有线充电存在的技术问题，电动汽车的无线充电技术应运而生。利用无线充电技术实现对电动汽车的快速充电，同样也需要提高充电功率。例如将多个逆变器的输出端并联在一起提供更大的充电功率。
此外，在感应加热领域，同样需要将多个逆变器高频并联在一起，以提供更大的加热功率。
而采用多个逆变器输出端并联的模式时，由于各个逆变器可能在参数、驱动延时等方面存在差异，会导致各个逆变器输出电流不均，即有的逆变器输出电流较大，有的逆变器输出电流较小，进而导致各个逆变器的发热不同，严重时甚至可能发生炸机现象。
因此，为了防止发生上述现象，应保证各个并联逆变器的输出电流均流。
目前一般通过在各个逆变器输出端连接电感等硬件器件，抑制多个逆变器并联运行时由于输出电流不均而出现环流和发热不均现象。并且，为了有效地抑制环流现象，一般需要选取感抗值较大的电感感抗值较大的电感，体积均较大，将其应用于实际产品中，一方面导致所占空间较大，另一方面是成本较高。
为了解决上述技术问题，本申请实施例提供了一种逆变器高频并联时的均流方法，该方法应用于至少两个逆变器高频输出端并联的情况，并且各个逆变器输出端呈感性。具体地，将各个逆变器的无功电流与无功电流参考值进行比较，获得各个逆变器的无功电流差值，根据各个逆变器的无功电流差值相应地调节各逆变器输入电压幅值；将各个逆变器的有功电流与有功电流参考值进行比较，获得各个逆变器的有功电流差值，根据各个逆变器的有功电流差值，调节各个逆变器自身的载波信号与载波同步信号之间的相位差，其中，载波同步信号为给定信号。
本申请实施例提供的均流方法，在逆变器输出端呈感性的条件下，通过调节逆变器输入电压幅值，调节逆变器输出的无功电流，使得各个逆变器输出的无功电流均流；通过调节各个逆变器自身载波信号与载波同步信号之间的相位差，调节逆变器输出的有功电流，使得各个逆变器输出的有功电流均流。各个逆变器输出的无功电流和有功电流都实现均流，即可保证各个逆变器输出的电流均流。该均流方法无需在电路中设置体积较大的硬件电子器件，仅通过调节各个逆变器输入电压幅值，以及自身载波信号与载波同步信号之间的相位差，即可保证各个逆变器输出的电流均流。
方法实施例一
参见图1，为本实施例提供的一种逆变器高频并联时的均流方法的流程图。
该方法应用于在多逆变器的输出端高频并联时实现均流，多个逆变器至少包括以下两个逆变器：第一逆变器和第二逆变器，并且第一逆变器和第二逆变器的输出端相互并联并呈感性。
本申请实施例提供的方法适用于逆变器高频并联。高频并联是指各个逆变器并联在一起的输出电压的频率与逆变器的开关频率相同，一般为几百Hz到几百kHz。逆变器的高频输出电压区别于逆变器的工频输出电压，逆变器的高频输出电压是与逆变器开关频率相同的方波，而逆变器工频输出电压通常为工频的正弦波。对于逆变器的工频输出，高频谐波属于干扰信号，需要滤除。而逆变器的高频输出电压则是与逆变器自身开关频率相同的方波，因此，高频信号不是干扰信号。
本实施例提供的方法，所应用的逆变器输出端应呈感性。具体的，可以通过在各个逆变器的输出端连接电感来实现，呈感性是指逆变器的输出电压的相位超前电感电流的相位。电感的感抗值不需要过大，保证逆变器的输出端呈感性即可。此处的电感不同于利用电感实现多个逆变器并联均流的电感。如果利用电感实现均流，电感的感抗值需要足够大，才可以起到均流效果，而本实施例提供的方法仅需要在逆变器输出端连接感抗值较小的电感即可。感抗值较小的电感的体积较小，并且成本均较低。
该均流方法适用于两个或两个以上高频输出端并联在一起的逆变器，为了描述方便，本实施例中以两个逆变器的输出端并联在一起为例进行介绍。该均流方法包括：
步骤101：将第一逆变器的无功电流和第二逆变器的无功电流均与无功电流参考值进行比较，分别获得第一逆变器的无功电流差值和第二逆变器的无功电流差值；。由于各个逆变器的输出端均呈感性，因此，可以通过调节各个逆变器的输入电压幅值，调节各个逆变器输出的无功电流。
一般可以利用霍尔元件、CT等电流传感器采样逆变器输出电流，并进行有功电流和无功电流的分解获取各个逆变器输出的无功电流，将各个逆变器输出的无功电流与无功电流参考值进行比较。也可以利用无功电流和输出电压的位置关系进行采样。
具体的，在各个逆变器输出电压正负跳变时刻，采集各个逆变器的输出电流为各个逆变器的无功电流。需要说明的是，逆变器输出电压正负跳变，包括输出电压从正到负跳变，也包括输出电压从负到正跳变。如图2所示，点1和点3对应的电流值即为逆变器输出的 无功电流值。
此外，获得各个逆变器的无功电流后，可以计算各个逆变器的无功电流的平均值，将该无功电流的平均值作为无功电流参考值。当然，也可以根据实际情况，设定某一电流值作为无功电流参考值，在此不对无功电流参考值的确定方法做任何限定。
具体的，该无功电流差值可以为各个逆变器输出的无功电流与无功电流参考值相减得到的差值。
步骤102：将第一逆变器的有功电流和第二逆变器的有功电流均与有功电流参考值进行比较，分别获得第一逆变器的有功电流差值和第二逆变器的有功电流差值；
由于各个逆变器的输出端呈感性，因此，可以通过调节各个逆变器的自身载波信号与载波同步信号之间的相位差，调节各个逆变器输出的有功电流。
一般可以利用霍尔元件、CT等电流传感器采样逆变器输出电流，并进行有功电流和无功电流的分解，获取各个逆变器输出的有功电流，将各个逆变器输出的有功电流与有功电流参考值进行比较。也可以利用无功电流和输出电压的位置关系进行采样。具体的，在各个逆变器输出电压正半周期或负半周期的中点时刻，采集各个逆变器输出电流为各个逆变器的有功电流。如图2a所示，点2和点4对应的电流值即为逆变器的有功电流值。
利用各个逆变器的有功电流获得各个逆变器的有功电流的平均值，可以将该有功电流的平均值作为有功电流参考值。当然，也可以根据实际情况，设定某一电流值作为有功电流参考值，在此不对有功电流参考值的确定方法做任何限定。
具体的，该有功电流差值可以为各个逆变器输出的有功电流与有功电流参考值相减得到的差值。
步骤103：分别根据所述第一逆变器的无功电流差值和第二逆变器的无功电流差值调节第一逆变器和第二逆变器的输入电压幅值；根据所述第一逆变器的有功电流差值和第二逆变器的有功电流差值分别调节第一逆变器和第二逆变器自身产生的载波信号与载波同步信号之间的相位差，以使所述第一逆变器的输出电流与所述第二逆变器的输出电流实现均流；所述载波同步信号为同时对所述两个逆变器输入的脉冲信号。
根据各个逆变器的无功电流差值，调节各个逆变器的输入电压幅值，进而调节逆变器输出的无功电流，以使各个逆变器的无功电流与无功电流参考值的差值，均在预设的范围内，即各个逆变器的无功电流均接近或等于无功电流参考值，从而各个逆变器的无功电流达到均流。
根据各个逆变器的有功电流差值，调节各个逆变器自身载波信号与载波同步信号之间的相位差，进而调节各个逆变器的有功电流，以使调节后的各个逆变器的有功电流与有功电流参考值之间的差值，均在预设的范围内，即各个逆变器的有功电流均接近或等于有功电流参考值，从而各个逆变器的有功电流达到均流。
步骤101与步骤102为独立的两个步骤，没有先后顺序一般需要同步执行步骤101和步骤102。即需要同步调节各个逆变器的无功电流和有功电流，以保证各个逆变器的无功电流和有功电流同时达到均流，进而，保证各个逆变器输出的电流达到均流。
为了更本领域技术人员更直观地理解本申请实施例提供的方法，下面结合下垂特性曲线介绍有功电流调节和无功电流调节的原理。
参见图2b，该图为逆变器的输入电压与逆变器的无功电流的下垂特性曲线示意图。
从图2b中可以看出，横轴为无功电流，纵轴为输入电压，直线表示输入电压与无功电流的下垂特性。当无功电流为I kq_set时，对应的输入电压为U bus_set；当无功电流为I kq时，对应的输入电压为U bus；即不同的无功电流对应不同的输入电压，但是输入电压和无功电流满足图2b所示的下垂特性。
参见图2c，该图为同步载波信号与逆变器的载波信号的相位差与有功电流的下垂特性曲线示意图。
从图2c中可以看出，横轴为有功电流，纵轴为相位差，直线表示相位差与有功电流的下垂特性。当有功电流为时，对应的相位差为；当有功电流为时，对应的相位差为；即不同的有功电流对应不同的相位差，但是相位差和有功电流满足图2c所示的下垂特性。
只有逆变器的输出端呈感性时才满足图2b和图2c所示的下垂特性。
下面结合实际的应用场景，对本实施例提供的均流方法进行介绍：
如图3所示，为基于本实施例提供的均流方法，提供的一种均流电路的电路图。
该均流电路可以应用于无线充电领域，以提供较大的充电功率，实现快速充电。也可以应用于感应加热领域，提供较大的功率，以实现快速加热。
第一至第N逆变器均为逆变器，第一至第N逆变器并联连接，并且在每个逆变器的正负输出端各串联一个电感，以保证各个逆变器的输出端呈感性。
各个逆变器的输入端分别连接独立的可变直流电源，以便调节各个逆变器的输入电压幅值。通过调节各个逆变器的输入电压幅值调节各个逆变器输出的无功电流，使得各个逆变器输出的无功电流均流。可以通过调节各个逆变器自身载波信号与载波同步信号之间的相位差调节逆变器输出的有功电流，使得各个逆变器输出的有功电流均流。
各个逆变器经电感并联至正公共并联点A和负公共并联点B，后级设备的两端分别连接正公共并联点A和负公共并联点B。具体的，后级设备可以为发射端补偿网络、发射线圈等部件，以实现在发射线圈上将高频交流电流转换为交变磁场，进而通过电磁感应，将交变磁场再转换为可为其他负载进行供电的交流电压或直流电压，以实现无线充电。
本实施例提供的均流方法，在逆变器的输出端呈感性的条件下，通过调节逆变器输入电压幅值，调节逆变器输出的无功电流，使得各逆变器输出的无功电流均流；通过调节各个逆变器自身载波信号与载波同步信号之间的相位差，调节逆变器输出的有功电流，使得各逆变器输出的有功电流均流。各逆变器输出的无功电流和有功电流都实现均流，即可保证各逆变器输出的电流均流。该均流方法无需在电路中设置较多体积较大的硬件电子器件，仅通过调节各逆变器输入电压幅值，以及自身载波信号与载波同步信号之间的相位差，即可保证各个逆变器输出的电流均流。
本实施例提供的方法应用于逆变器高频并联，区别于逆变器工频并联。其中光伏并网发电属于逆变器工频并联。对于光伏并网发电领域的多个逆变器并联均流控制，采用的是脉冲宽度调制(PWM，Pulse Width Modulation)技术，即通过调节每个桥臂开关管的导通 脉冲宽度实现均流控制。而本实施例并不是通过调节PWM来实现各个逆变器的均流，而是通过调节各个逆变器的直流母线电压以及各个逆变器自身载波信号与载波同步信号的相位差来实现均流控制。
另外，本申请实施例提供的方法可以实现各个逆变器的无功电流相等，有功电流也相等。当各个逆变器的无功电流相等时，实现对于总的无功功率的均分，从而可以使各个逆变器的开关管达到软开关的效果，从而降低开关管的功耗，提高电能效率。
本申请实施例提供的均流方法，通过调节逆变器的无功电流和有功电流达到均流，进而达到逆变器输出电流均流的效果。下面分别对无功电流的调节方法和有功电流的调节方法进行详细介绍。
首先，介绍逆变器无功电流的调节方法。
方法实施例二
参见图4，为本实施例提供的逆变器的无功电流调节方法的流程图。
该无功电流调节方法适用于两个或两个以上高频输出端并联在一起的逆变器，为了描述方便，本实施例中以两个逆变器的输出端并联在一起为例进行介绍。该均流方法包括：
步骤401：根据第一逆变器的无功电流差值获得第一电压微调量；根据第二逆变器的无功电流差值获得第二电压微调量。
获得各个逆变器的无功电流差值后，将各个逆变器的无功电流差值相应地输入无功电流调节器，经无功电流调节器进行补偿处理后，获得对应于不同逆变器的电压微调量。
每个逆变器均可相应地配备一个无功电流调节器，以获得对应于各个逆变器的电压微调量。当然，也可以多个逆变器通过一个无功电流调节器，获取对应于各个逆变器的电压微调量，在此不做任何限定。
步骤402：将第一电压微调量与第一电压调节量设定值相叠加，获得第一逆变器的输入电压给定值；将第二电压微调量与第二电压调节量设定值相叠加，获得第二逆变器的输入电压给定值。
将在步骤401中获得的各个逆变器的电压微调量，相对应的与各个逆变器的电压调节量设定值进行叠加，从而获得各个逆变器的输入电压给定值。
各个逆变器的电压调节量设定值为预先设定的值。一般根据实际情况，设定各个逆变器的电压调节量设定值，具体的，可以根据逆变器后级连接的负载所需要的功率，设定各个逆变器的电压调节量设定值。
步骤403：根据第一逆变器的输入电压给定值，调节第一逆变器的输入电压幅值；根据第二逆变器的输入电压给定值，调节第二逆变器的输入电压幅值。
根据步骤402中获得的各个逆变器的输入电压给定值，相应地调节各个逆变器的输入电压幅值。
具体的，可以调节各个逆变器连接的可变直流电源，将各个可变直流电源输出的电压幅值，相应地调节为在步骤402中获得的输入电压给定值。当然，也可以通过调节各个逆变器连接的变压设备，将各个逆变器的输入电压幅值，相应地调节为输入电压给定值。
通过调节输入电压幅值调节各个逆变器输出的无功电流，以使各个逆变器输出的无功电流与无功电流参考值的差值在预设的范围内，即各个逆变器输出的无功电流达到无功电流参考值，或接近无功电流参考值，即实现各个逆变器输出的无功电流均流。
如图5所示，为对逆变器的无功电流调节过程的示意图。
将采集的逆变器的无功电流与无功电流参考值做差，得到无功电流差值，将该无功电流差值输入无功电流调节器进行处理，得到电压微调量，将电压微调量与电压调节量设定值进行叠加，即可得到输入电压给定值，根据该输入电压给定值，调节逆变器的输入电压幅值，进而实现无功电流的调节。
本实施例提供的逆变器的无功电流调节方法，能够通过调节各个逆变器的输入电压幅值，使得各个逆变器输出的无功电流达到均流。并且，各个逆变器输出的无功电流达到均流，还可以使得各个逆变器处于软开关(ZVS，Zero Voltage Switch)工作状态，降低各个逆变器的开关损耗。
下面介绍逆变器的有功电流调节方法。
方法实施例三
参见图6，为本实施例提供的逆变器的有功电流调节方法的流程图，该均流方法适用于两个或两个以上高频输出端并联在一起的逆变器，为了描述方便，本实施例中以两个逆变器的输出端并联在一起为例进行介绍。该均流方法包括：
步骤601：根据第一逆变器的有功电流差值获得第一角度微调量；根据第二逆变器的有功电流差值获得第二角度微调量。
获得各个逆变器的有功电流差值后，将各个逆变器的有功电流差值相应地输入有功电流调节器，经有功电流调节器进行补偿处理后，获得对应于不同逆变器的角度微调量。
需要说明的是，每个逆变器均可相应地配备一个有功电流调节器，以获得对应于各个逆变器的角度微调量。当然，也可以多个逆变器通过一个有功电流调节器，获取对应于各个逆变器的角度微调量，在此不做任何限定。
步骤602：将第一角度微调量与第一角度调节量设定值相叠加，获得第一逆变器自身载波信号相位给定值；将第二角度微调量与第二角度调节量设定值相叠加，获得第二逆变器自身载波信号相位给定值。
将在步骤601中获得的各个逆变器的角度微调量，相对应的与各个逆变器的角度调节量设定值进行叠加，从而获得各个逆变器自身载波信号相位给定值。
各个逆变器的角度调节量设定值为预先设定的角度值，该角度调节量设定值具体与连接的后级设备的功率相关，若连接的后级设备功率发生改变，该角度调节量设定值也需要相应的改变。该角度调节量设定值可以为0，当然，也可以根据实际情况，设定为任一角度值为角度调节量设定值，在此不做任何限定。
步骤603：根据第一逆变器自身载波信号相位给定值，调节第一逆变器自身载波信号与载波同步信号之间的相位差；根据第二逆变器自身载波信号相位给定值，调节第二逆变器自身载波信号与载波同步信号之间的相位差。
根据步骤602中获得的各个逆变器自身载波信号相位给定值，相应地调节各个逆变器自身载波信号与载波同步信号之间的相位差。
具体的，可以调节各个逆变器自身载波信号，使得各个逆变器自身载波信号与载波同步信号之间的相位差为各个逆变器自身载波信号相位给定值。
由于逆变器自身的载波信号与载波同步信号之间的相差，和逆变器的有功电流成正比，因此，通过调节逆变器自身的载波信号与载波同步信号之间的相差，即可使得各个逆变器输出的有功电流与有功电流参考值的差值在预设范围内，即各个逆变器输出的有功电流均达到或接近有功电流参考值，从而，实现各个逆变器输出的有功电流均流。
如图7a所示，逆变器输出电压的相位可以表示逆变器自身载波信号，该输出电压的相位与载波同步信号之间的相位差角δ，即为逆变器自身载波信号与载波同步信号之间的相位差。
如图7b所示，为对逆变器的有功电流调节过程的示意图。
将采集的逆变器的有功电流与有功电流参考值做差，得到有功电流差值，将该有功电流差值输入有功电流调节器进行处理，得到角度微调量。将角度微调量与角度调节量设定值进行叠加，即可得到载波信号相位给定值，进而根据该载波信号相位给定值，调节逆变器自身载波信号与载波同步信号的相位差，进而实现有功电流的调节。
本实施例提供的逆变器有功电流调节方法，能够通过调节各个逆变器自身载波信号与载波同步信号之间的相位差，调节各个逆变器输出的有功电流达到均流。
结合方法实施例二提供的逆变器无功电流调节方法，在有功电流与无功电流均达到均流的条件下，实现调节并联各个逆变器输出的电流达到均流。
基于上述实施例提供的逆变器高频并联时的均流方法，本申请实施例还提供了一种逆变器高频并联时的均流装置，下面结合附图对其工作原理进行详细的介绍。
装置实施例一
参见图8a，为本实施例提供的一种逆变器高频并联时的均流装置的结构图。
该装置应用于至少以下两个逆变器高频输出端并联。两个逆变器包括：第一逆变器801和第二逆变器802。
该均流装置包括：第一逆变器控制器803、第二逆变器控制器804、第一电感组件805和第二电感组件806。
该均流装置适用于两个或两个以上高频输出端并联在一起的逆变器，为了描述方便，本实施例中以两个逆变器的输出端并联在一起为例进行介绍。其中，每个逆变器均配备一个对应的逆变器控制器，且每个逆变器控制器之间可以进行通讯。
需要说明的是，每个逆变器的结构可以相同，每个逆变器控制器的结构也可以相同。
第一逆变器801的输出端通过第一电感组件805连接公共并联点，第二逆变器802的输出端通过第二电感组件806连接公共并联点，第一电感组件805使第一逆变器的输出端呈现感性，第二电感组件806使第二逆变器的输出端呈现感性。
在第一电感组件805和第二电感组件806后连接后级设备807，后级设备807可以为 发射补偿网络、发射线圈等用于为负载充电的设备。
第一逆变器控制器803，用于将第一逆变器801的无功电流与无功电流参考值进行比较，获得第一逆变器801的无功电流差值，根据第一逆变器801的无功电流差值调节第一逆变器801的输入电压幅值；还用于将第一逆变器801的有功电流与有功电流参考值进行比较，获得第一逆变器801的有功电流差值，根据第一逆变器801的有功电流差值调节第一逆变器801自身产生的载波信号与载波同步信号之间的相位差。
第二逆变器控制器804，用于将第二逆变器802的无功电流与无功电流参考值进行比较，获得第二逆变器802的无功电流差值，根据第二逆变器802的无功电流差值调节第二逆变器802的输入电压幅值；还用于将第二逆变器802的有功电流与有功电流参考值进行比较，获得第二逆变器802的有功电流差值，根据第二逆变器802的有功电流差值调节第二逆变器802自身产生的载波信号与载波同步信号之间的相位差。所述载波同步信号为同时对所述两个逆变器同时输入的脉冲信号。
其中，第一逆变器801和第二逆变器802可以为H桥结构的逆变器，如图8b所示，由开关管S1和S2构成桥臂1，开关管S3和S4构成桥臂2，Uak为桥臂1的中点电压，Ubk为桥臂2的中点电压，Uak与Ubk的差值为该逆变器的输出电压。通过调节直流可调电源Vdck，可以调节逆变器的输出电压。
本实施例图8a所示的装置是方法实施例一对应的装置，具体方法可以参考方法实施例一的描述，在此不再赘述。
本实施例提供的均流装置，在逆变器的输出端呈感性的条件下，通过调节逆变器输入电压幅值，调节逆变器输出的无功电流，使得各逆变器输出的无功电流均流；通过调节各个逆变器自身载波信号与载波同步信号之间的相位差，调节逆变器输出的有功电流，使得各逆变器输出的有功电流均流。各逆变器输出的无功电流和有功电流都实现均流，即可保证各逆变器输出的电流均流。该均流装置中无需设置较多体积较大的硬件电子器件，仅通过调节各逆变器输入电压幅值，以及自身载波信号与载波同步信号之间的相位差，即可保证各个逆变器输出的电流均流。
上述实施例提供的逆变器高频并联时的均流装置，可以在第一逆变器控制器和第二逆变器控制器等逆变器控制器中，以预定机制选择出主机和从机。载波同步信号可以由主机产生，并将其发送给从机。
具体的，可以按照上电的先后顺序确定主机，即各个逆变器控制器中，确定最先上电的逆变器控制器为主机，其他逆变器控制器为从机。当然，也可以按照其他预定机制选择主机和从机，在此不做任何限定。
在选择出主机和从机后，本申请提供的均流装置一般采用以下两种实现方式，确定并发送无功电流参考值以及有功电流参考值至各个逆变器控制器。
第一种实现方式，由主机确定该均流装置的无功电流参考值和有功电流参考值，并由主机将无功电流参考值和有功电流参考值发送至各个从机。
第二种实现方式，由主机和各个从机确定该均流装置的无功电流参考值和有功电流参考值，主机和各个从机直接利用自身确定出的无功电流参考值和有功电流参考值。
下面对以上两种实现方式进行具体介绍。
需要说明的是，以下实施例中的均流装置适用于两个或两个以上高频输出端并联在一起的逆变器，为了便于描述，以下实施例中均以两个逆变器的输出端并联在一起为例进行介绍。
其中，每个逆变器均配备一个对应的逆变器控制器，且每个逆变器控制器之间可以进行通讯。并且，以下实施例中的均流装置均假定第一逆变器控制器为主机，其他逆变器控制器为从机。
首先对第一种实现方式中的均流装置进行介绍。
装置实施例二
参见图9，为本实施例提供的另一种逆变器高频并联时的均流装置的结构图。
该均流装置除了装置实施例一所包括的部件外，还包括：第一无功电流采样电路901、第一有功电流采样电路902、第二无功电流采样电路903和第二有功电流采样电路904。
第一无功电流采样电路901，用于获得第一逆变器801的无功电流。
第一有功电流采样电路902，用于获得第一逆变器801的有功电流。
第二无功电流采样电路903，用于获得第二逆变器802的无功电流。
第二有功电流采样电路904，用于获得第二逆变器802的有功电流。
主机，用于由第一逆变器801的无功电流和第二逆变器802的无功电流获得无功电流平均值，将无功电流平均值作为所述无功电流参考值，并将所述无功电流参考值发送给所述从机；还用于由第一逆变器801的有功电流和第二逆变器802的有功电流获得有功电流平均值，将有功电流平均值作为有功电流参考值，并将有功电流参考值发送给所述从机。
如图9所示，第一逆变器控制器803为主机，由主机发送载波同步信号至载波同步信号总线，载波同步信号总线将该载波同步信号发送至其他各个从机。
如图9所示，第一无功电流采样电路901采集第一逆变器的无功电流，并将采集到的第一逆变器的无功电流发送至第一逆变器控制器803；第一有功电流采样电路902采集第一逆变器的有功电流，并将采集到的第一逆变器的有功电流发送至第一逆变器控制器803。
第一无功电流采样电路901与第一有功电流采样电路902，可以均从第一逆变器的正输出端，采集第一逆变器的无功电流和有功电流；也可以均从第一逆变器的负输出端，采集第一逆变器的无功电流和有功电流；还可以分别从第一逆变器的正输出端和第一逆变器的负输出端，采集第一逆变器的无功电流和有功电流，在此不对第一无功电流采样电路和第一有功电流采样电路采集电流的位置做限定。
第一逆变器控制器803将第一逆变器的无功电流和有功电流发送至有线通信总线。
其他逆变模块在采集和发送无功电流、有功电流方面的工作方式，与第一逆变模块中的工作方式相同，在此不再赘述。
第一逆变器控制器803作为主机，采集各个逆变器发送至有线通信总线的无功电流和有功电流，根据各个逆变器发送的无功电流，计算无功电流平均值，并将该无功电流平均值作为无功电流参考值；根据各个逆变器发送的有功电流，计算有功电流平均值，并将该 有功电流平均值作为有功电流参考值。
第一逆变器控制器803将无功电流参考值和有功电流参考值，发送至有线通信总线，由有线通信总线将该无功电流参考值和有功电流参考值，发送至各个逆变器控制器。
其他逆变器控制器作为从机，接收主机发送至有线通信总线的无功电流参考值和有功电流参考值，进而根据无功电流参考值和有功电流参考值，调节各个逆变器的无功电流和有功电流。
本实施例提供的均流装置，在各个逆变器控制器中确定主机和从机，由主机发送载波同步信号，并由主机确定该均流装置的无功电流参考值和有功电流参考值。在逆变器的输出端呈感性的条件下，通过调节逆变器输入电压幅值，调节逆变器输出的无功电流，使得各逆变器输出的无功电流均流；通过调节各个逆变器自身载波信号与载波同步信号之间的相位差，调节逆变器输出的有功电流，使得各逆变器输出的有功电流均流。各逆变器输出的无功电流和有功电流都实现均流，即可保证各逆变器输出的电流均流。该均流装置中无需设置较多体积较大的硬件电子器件，仅通过调节各逆变器输入电压幅值，以及自身载波信号与载波同步信号之间的相位差，即可保证各个逆变器输出的电流均流。
下面介绍对第二种实现方式中的均流装置。
装置实施例三
参见图10，为本实施例提供的又一种逆变器高频并联时的均流装置的结构图。
该均流装置除了装置实施例一所包括的部件外，还包括：第一无功电流采样电路1001、第一有功电流采样电路1002、第二无功电流采样电路1003和第二有功电流采样电路1004。
第一无功电流采样电路1001，用于获得第一逆变器的无功电流。
第一有功电流采样电路1002，用于获得第一逆变器的有功电流。
第二无功电流采样电路1003，用于获得第二逆变器的无功电流。
第二有功电流采样电路1004，用于获得第二逆变器的有功电流。
第一逆变器控制器801，用于由第一逆变器801的无功电流和第二逆变器802的无功电流获得无功电流平均值，将无功电流平均值作为无功电流参考值；还用于由第一逆变器801的有功电流和第二逆变器802的有功电流获得有功电流平均值，将有功电流平均值作为所述有功电流参考值。
第二逆变器控制器802，用于由第一逆变器801的无功电流和第二逆变器802的无功电流获得无功电流平均值，将无功电流平均值作为所述无功电流参考值；还用于由第一逆变器801的有功电流和第二逆变器802的有功电流获得有功电流平均值，将有功电流平均值作为有功电流参考值。
如图10所示，第一逆变器控制器803为主机，由主机发送载波同步信号至载波同步信号总线，载波同步信号总线将该载波同步信号发送至其他从机。
如图10所示，第一无功电流采样电路1001采集第一逆变器的无功电流，并将采集到的第一逆变器的无功电流发送至第一逆变器控制器803；第一有功电流采样电路1002采集第一逆变器的有功电流，并将采集到的第一逆变器的有功电流发送至第一逆变器控制器 803。
第一无功电流采样电路1001与第一有功电流采样电路1002，可以均从第一逆变器的正输出端，采集第一逆变器的无功电流和有功电流；也可以均从第一逆变器的负输出端，采集第一逆变器的无功电流和有功电流；还可以分别从第一逆变器的正输出端和第一逆变器的负输出端，采集第一逆变器的无功电流和有功电流，在此不对第一无功电流采样电路和第一有功电流采样电路采集电流的位置做限定。
第一逆变器控制器803将第一逆变器的无功电流和有功电流发送至有线通信总线。
其他逆变模块与第一逆变模块的工作方式相同，由相应的无功电流采样电路采集逆变器的无功电流，并将无功电流发送至对应的逆变器控制器；由相应的有功电流采样电路采集逆变器的有功电流，并将有功电流发送至对应的逆变器控制器。再由各个逆变器控制器将各个逆变器的无功电流和有功电流发送至有线通信总线。
每个逆变器控制器在有线通信总线上，采集各个逆变器控制器发送的无功电流，并根据各个无功电流，计算无功电流平均值，将该无功电流平均值作为无功电流参考值。进而，根据该无功电流参考值，调节相对应的逆变器的无功电流，使该逆变器的无功电流与无功电流参考值之间的差值在预设的范围内。
每个逆变器控制器在有线通信总线上，采集各个逆变器控制器发送的有功电流，并根据各个有功电流，计算有功电流平均值，将该有功电流平均值作为有功电流参考值。进而，根据该有功电流参考值，调节相对应的逆变器的有功电流，使该逆变器的有功电流与有功电流参考值之间的差值在预设的范围内。
本实施例提供的均流装置，在各个逆变器控制器中确定主机和从机，由主机发送载波同步信号。主机和从机均接收有线通信总线上的各个逆变器的无功电流和有功电流，主机和从机均根据各个逆变器的无功电流和有功电流计算无功电流参考值和有功电流参考值。在逆变器的输出端呈感性的条件下，通过调节逆变器输入电压幅值，调节逆变器输出的无功电流，使得各逆变器输出的无功电流均流；通过调节各个逆变器自身载波信号与载波同步信号之间的相位差，调节逆变器输出的有功电流，使得各逆变器输出的有功电流均流。各逆变器输出的无功电流和有功电流都实现均流，即可保证各逆变器输出的电流均流。该均流装置中无需设置较多体积较大的硬件电子器件，仅通过调节各逆变器输入电压幅值，以及自身载波信号与载波同步信号之间的相位差，即可保证各个逆变器输出的电流均流。
基于上述实施例提供的逆变器高频并联时的均流方法和装置，本申请实施例还提供了一种逆变器高频并联时的逆变系统，下面结合附图对其工作原理进行详细的介绍。
系统实施例一
参见图11，为本实施例提供的一种逆变器高频并联时的逆变系统的结构图。
该系统包括上述装置实施例中的均流装置，还包括至少以下两个逆变器高频输出端并联：第一逆变器801和第二逆变器802。
需要说明的是，为了更清楚的介绍逆变系统中的其他部件，在附图中将均流装置进行了简化，仅以各个逆变器来表示装置实施例中的均流装置。
第一逆变器801的输入端连接第一可调电源Vdc1。
第二逆变器802的输入端连接第二可调电源Vdc2。
通过调节各个逆变器的输入端连接的可调电源的电压幅值，调节逆变器的输入电压幅值，进而调节逆变器的无功电流，使得各个逆变器输出的无功电流均流。
如图11所示，为本实施例提供的逆变系统应用于无线充电领域的结构图。各个逆变器并联连接至正公共并联点A和负公共并联点B，各个逆变器将可调电源输入的直流电压，逆变为高频交流电压，高频交流电压通过发射端补偿网络1101，在发射线圈上产生交变的电流，交变的电流产生交变的磁场。
接收线圈通过电磁感应，在接收线圈两端感应出交流电压，经接收端补偿网络1102和整流滤波电路1103，将感应出的交流电压转换为负载所需的直流电压。
本实施例提供的逆变系统，在逆变器的输出端呈感性的条件下，通过调节逆变器输入电压幅值，调节逆变器输出的无功电流，使得各逆变器输出的无功电流均流；通过调节各个逆变器自身载波信号与载波同步信号之间的相位差，调节逆变器输出的有功电流，使得各逆变器输出的有功电流均流。各逆变器输出的无功电流和有功电流都实现均流，即可保证各逆变器输出的电流均流。该逆变系统中无需设置较多体积较大的硬件电子器件，仅通过调节各逆变器输入电压幅值，以及自身载波信号与载波同步信号之间的相位差，即可保证各个逆变器输出的电流均流。
系统实施例一提供的逆变系统中的可调电源，可以为直流可调电源，也可以为交流可调电源，当为交流可调电源时，需要整流器将交流整流为直流后提供为逆变器的输入端。
下面介绍可调电源为直流可调电源的实施例。
系统实施例二
参见图12，为本实施例提供的另一种逆变系统的结构图。
该系统中可调电源为直流可调电源，为了使附图能够表示的更清晰，图12中仅画出了与第一逆变器801相连的第一直流-直流变换器1201，以及第一直流可调电源Vdc1。与其余逆变器相连的直流-直流变换器均可以与第一直流-直流变换器相同，其余直流可调电源也均可以与第一直流可调电源相同。
第一直流-直流变换器1201，用于将第一直流可调电源Vdc1输出的电压进行转换后输送给所述第一逆变器的输入端。
相应地，其余直流可调电源输出的电压，经与之对应的直流-直流变换器，将直流可调电源输出的电压进行转换。
需要说明的是，直流-直流变换器可以为Boost升压电路，也可以为Buck降压电路，还可以为Boost-Buck升降压电路，在此不对直流-直流变换器的类型进行限定。
此外，直流可调电源还可以由两个直流可调电源串联组成，如图13所示，第一直流可调电源由直流可调电源Vdc1u和直流可调电源Vdc1d串联组成。
本实施例提供的逆变系统，在逆变器的输出端呈感性的条件下，可以通过调节各个直流可调电源以及各个直流-直流变换器，调节各个逆变器的输入电压幅值，进而调节各个逆 变器输出的无功电流达到均流。再对各个逆变器自身载波信号与载波同步信号之间的相位差进行调节，以调节逆变器输出的有功电流，使得各逆变器输出的有功电流均流。各逆变器输出的无功电流和有功电流都实现均流，即可保证各逆变器输出的电流均流。
下面介绍可调电源为交流可调电源实施例。
系统实施例三
参见图14，为本实施例提供的又一种逆变系统的结构图。
该系统中可调电源为交流可调电源，为了使附图能够表示的更清晰，图14中仅画出了与第一逆变器801相连的第一交流-直流变换器1401，以及第一交流可调电源Vin1。与其余逆变器相连的交流-直流变换器均可以与第一交流-直流变换器相同，其余交流可调电源也均可以与第一交流可调电源相同。
第一交流-直流变换器1401，用于将第一交流可调电源Vin1整流为直流电后输送给第一逆变器的输入端。
相应地，其余交流可调电源输出的电压，经与之对应的交流-直流变换器处理，将交流可调电源输出的电压进行转换。
此外，如图15所示，还可以采用功率因素校正(PFC，Power Factor Correction)电路1501，将电网中的交流电压变换为直流电压，具体的，由于PFC电路中包含整流电路，因此可以将电网中的交流电压整流为直流电压。再根据逆变器控制器发出的指令，利用直流-直流变换器1502调节该直流电压作为逆变器的输入电压，进而调节逆变器输出的无功电流。
由于PFC电路中的交流-直流变换器也可以受逆变器控制器的控制，因此，系统中仅设置PFC电路也可以实现调节逆变器输入电压的功能。如图16所示，将逆变器控制器发出的指令发送至PFC电路1501，根据该指令，PFC电路1501将电网中的交流电压转换为所需要的直流电压，并将该直流电压作为逆变器的输入电压，实现调节无功电流的目的。
本实施例提供的逆变系统，在逆变器的输出端呈感性的条件下，可以通过调节各个交流可调电源以及各个交流-直流变换器，调节各个逆变器的输入电压幅值，进而调节各个逆变器输出的无功电流达到均流。再对各个逆变器自身载波信号与载波同步信号之间的相位差进行调节，以调节逆变器输出的有功电流，使得各逆变器输出的有功电流均流。各逆变器输出的无功电流和有功电流都实现均流，即可保证各逆变器输出的电流均流。
本申请实施例还提供一种无线充电系统，例如用于为电动汽车充电时，负载可以为电动汽车的蓄电池。具体可以参见图11-16所示的系统示意图。
本实施例提供的无线充电系统，包括以上实施例中的均流装置，还包括至少以下两个逆变器高频输出端并联：第一逆变器和第二逆变器；还包括：第一可调电源、第二可调电源、无线发射电路和无线接收电路；
所述第一逆变器的输入端连接第一可调电源；
所述第二逆变器的输入端连接第二可调电源；
所述第一逆变器的输出端连接所述无线发射电路的输入端；
所述第二逆变器的输出端连接所述无线发射电路的输入端；
所述无线发射电路通过无线方式将电能发射出去，所述无线接收电路通过无线方式接收所述无线发射电路发射的电能以给负载供电。
其中，无线发射电路包括发射补偿网络和发射线圈；所述无线接收电路包括接收补偿网络和接收线圈；
发射补偿网络的输入端作为所述无线发射电路的输入端，所述发射补偿网络的输出端连接所述发射线圈；
接收线圈连接所述接收补偿网络的输入端，所述接收补偿网络的输出端连接负载。
另外，以上实施例提供的逆变系统还可以应用于感应加热领域，此时负载可以为需要加热的设备，例如各种型材需要加热融化或变形。具体可以为铝质设备的铸造等。
以上所述，以上实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围。

Claims (15)

  1. 一种逆变器的均流方法，用于在多逆变器的输出端高频并联时实现均流，其特征在于，所述多逆变器至少包括两个逆变器：第一逆变器和第二逆变器；所述第一逆变器和第二逆变器的输出端相互并联并呈感性，所述方法包括：
    将所述第一逆变器的无功电流和所述第二逆变器的无功电流分别与无功电流参考值进行比较，分别获得第一逆变器的无功电流差值和第二逆变器的无功电流差值；
    将所述第一逆变器的有功电流和第二逆变器的有功电流分别与有功电流参考值进行比较，分别获得第一逆变器的无功电流差值和第二逆变器的有功电流差值；
    根据所述第一逆变器无功电流差值和第二逆变器的无功电流差值分别调节第一逆变器和第二逆变器的输入电压幅值，根据所述第一逆变器有功电流差值和第二逆变器的有功电流差值分别调节第一逆变器和第二逆变器自身产生的载波信号与载波同步信号之间的相位差，以使所述第一逆变器的输出电流与所述第二逆变器的输出电流实现均流，所述载波同步信号为同时对所述两个逆变器同时输入的脉冲信号。
  2. 根据权利要求1所述的逆变器均流方法，其特征在于，根据第一逆变器的无功电流差值调节第一逆变器的输入电压幅值，具体包括：
    根据第一逆变器的无功电流差值获得第一电压微调量；
    将所述第一电压微调量与第一电压调节量设定值相叠加获得第一逆变器的输入电压给定值；
    根据所述第一逆变器的输入电压给定值调节所述第一逆变器的输入电压幅值；
    根据第二逆变器的无功电流差值调节第二逆变器的输入电压幅值，具体包括：
    根据第二逆变器的无功电流差值获得第二电压微调量；
    将所述第二电压微调量与第二电压调节量设定值相叠加获得第二逆变器的输入电压给定值；
    根据所述第二逆变器的输入电压给定值调节所述第二逆变器的输入电压幅值。
  3. 根据权利要求1所述的逆变器均流方法，其特征在于，根据第一逆变器的有功电流差值调节第一逆变器自身载波信号与载波同步信号之间的相位差，具体包括：
    根据所述第一逆变器的有功电流差值获得第一角度微调量；
    将所述第一角度微调量与第一角度调节量设定值相叠加获得第一逆变器自身载波信号相位给定值；
    根据所述第一逆变器自身载波信号相位给定值调节第一逆变器自身载波信号与载波同步信号之间的相位差；
    根据第二逆变器的有功电流差值调节第二逆变器自身载波信号与所述载波同步信号之间的相位差，具体包括：
    根据所述第二逆变器的有功电流差值获得第二角度微调量；
    将所述第二角度微调量与第二角度调节量设定值相叠加获得第二逆变器自身载波信号相位给定值；
    根据所述第二逆变器自身载波信号相位给定值调节第二逆变器自身载波信号与载波 同步信号之间的相位差。
  4. 根据权利要求1-3任一项所述的逆变器均流方法，其特征在于，所述获得所述第一逆变器的有功电流和第二逆变器的有功电流，具体包括：
    在第一逆变器输出电压正半周期或负半周期的中点时刻采集第一逆变器输出电流为所述第一逆变器的有功电流；在第二逆变器输出电压正半周期或负半周期的中点时刻采集第二逆变器输出电流为所述第二逆变器的有功电流；
    所述获得所述第一逆变器的无功电流和第二逆变器的无功电流，具体包括：
    在第一逆变器输出电压正负跳变时刻采集第一逆变器输出电流为所述第一逆变器的无功电流；在第二逆变器输出电压正负跳变时刻采集第二逆变器输出电流为所述第二逆变器的无功电流。
  5. 根据权利要求1-3任一项所述的逆变器均流方法，其特征在于，所述第一逆变器和第二逆变器的输出电压并联在一起，且所述第一逆变器的输出电压的频率与所述第一逆变器的开关频率相同，所述第二逆变器的输出电压的频率与所述第二逆变器的开关频率相同。
  6. 根据权利要求1-3任一项所述的逆变器均流方法，其特征在于，所述无功电流参考值为所述第一逆变器的无功电流和第二逆变器的无功电流的平均值，所述有功电流参考值为所述第一逆变器的有功电流和第二逆变器的有功电流的平均值。
  7. 一种逆变器均流装置，其特征在于，用于在多逆变器的输出端高频并联时实现均流，所述多逆变器至少包括两个逆变器：第一逆变器和第二逆变器；所述第一逆变器和第二逆变器的输出端相互并联并呈感性，
    该均流装置包括：第一逆变器控制器、第二逆变器控制器、第一电感组件和第二电感组件；
    所述第一逆变器的输出端通过所述第一电感组件连接公共并联点，所述第二逆变器的输出端通过所述第二电感组件连接公共并联点，所述第一电感组件使所述第一逆变器的输出端呈现感性，所述第二电感组件使所述第二逆变器的输出端呈现感性；
    所述第一逆变器控制器，用于将所述第一逆变器的无功电流与无功电流参考值进行比较，获得第一逆变器的无功电流差值，根据第一逆变器的无功电流差值调节第一逆变器的输入电压幅值；还用于将所述第一逆变器的有功电流与有功电流参考值进行比较，获得第一逆变器的有功电流差值，根据第一逆变器的有功电流差值调节第一逆变器自身产生的载波信号与载波同步信号之间的相位差；所述载波同步信号为同时对所述两个逆变器同时输入的脉冲信号；
    所述第二逆变器控制器，用于将所述第二逆变器的无功电流与无功电流参考值进行比较，获得第二逆变器的无功电流差值，根据第二逆变器的无功电流差值调节第二逆变器的输入电压幅值；还用于将所述第二逆变器的有功电流与有功电流参考值进行比较，获得第二逆变器的有功电流差值，根据第二逆变器的有功电流差值调节第二逆变器自身产生的载波信号与所述载波同步信号之间的相位差。
  8. 根据权利要求7所述的逆变器均流装置，其特征在于，所述第一逆变器控制器和第二逆变器控制器以预定机制选择出主机和从机；
    所述载波同步信号由所述主机产生，并发送给所述从机。
  9. 根据权利要求8所述的逆变器均流装置，其特征在于，还包括：第一无功电流采样电路、第一有功电流采样电路、第二无功电流采样电路和第二有功电流采样电路；
    所述第一无功电流采样电路，用于获得所述第一逆变器的无功电流；
    所述第一有功电流采样电路，用于获得所述第一逆变器的有功电流；
    所述第二无功电流采样电路，用于获得所述第二逆变器的无功电流；
    所述第二有功电流采样电路，用于获得所述第二逆变器的有功电流；
    所述主机，用于由所述第一逆变器的无功电流和第二逆变器的无功电流获得无功电流平均值，将所述无功电流平均值作为所述无功电流参考值，并将所述无功电流参考值发送给所述从机；还用于由所述第一逆变器的有功电流和第二逆变器的有功电流获得有功电流平均值，将所述有功电流平均值作为所述有功电流参考值，并将所述有功电流参考值发送给所述从机。
  10. 根据权利要求7或8所述的逆变器均流装置，其特征在于，还包括：第一无功电流采样电路、第一有功电流采样电路、第二无功电流采样电路和第二有功电流采样电路；
    所述第一无功电流采样电路，用于获得所述第一逆变器的无功电流；
    所述第一有功电流采样电路，用于获得所述第一逆变器的有功电流；
    所述第二无功电流采样电路，用于获得所述第二逆变器的无功电流；
    所述第二有功电流采样电路，用于获得所述第二逆变器的有功电流；
    所述第一逆变器控制器，用于由所述第一逆变器的无功电流和第二逆变器的无功电流获得无功电流平均值，将所述无功电流平均值作为所述无功电流参考值；还用于由所述第一逆变器的有功电流和第二逆变器的有功电流获得有功电流平均值，将所述有功电流平均值作为所述有功电流参考值；
    所述第二逆变器控制器，用于由所述第一逆变器的无功电流和第二逆变器的无功电流获得无功电流平均值，将所述无功电流平均值作为所述无功电流参考值；还用于由所述第一逆变器的有功电流和第二逆变器的有功电流获得有功电流平均值，将所述有功电流平均值作为所述有功电流参考值。
  11. 一种逆变系统，其特征在于，包括权利要求7-10任一项所述的均流装置，还至少包括以下两个逆变器：第一逆变器和第二逆变器；
    所述第一逆变器的输入端连接第一可调电源；
    所述第二逆变器的输入端连接第二可调电源。
  12. 根据权利要求11所述的逆变系统，其特征在于，还包括：第一直流-直流变换器和第二直流-直流变换器；
    所述第一可调电源为第一直流可调电源，所述第二可调电源为第二直流可调电源；
    所述第一直流-直流变换器，用于将所述第一直流可调电源输出的电压进行转换后输送给所述第一逆变器的输入端；
    所述第二直流-直流变换器，用于将所述第二直流可调电源输出的电压进行转换后输送给所述第二逆变器的输入端；
  13. 根据权利要求11所述的逆变系统，其特征在于，还包括：第一交流-直流变换器和第二交流-直流变换器；
    所述第一可调电源为第一交流可调电源，所述第二可调电源为第二交流可调电源；
    所述第一交流-直流变换器，用于将所述第一交流可调电源整流为直流电后输送给所述第一逆变器的输入端；
    所述第二交流-直流变换器，用于将所述第二交流可调电源整流为直流电后输送给所述第二逆变器的输入端。
  14. 一种无线充电系统，其特征在于，包括权利要求7-10任一项所述的均流装置，还包括至少以下两个逆变器：第一逆变器和第二逆变器；
    还包括：第一可调电源、第二可调电源、无线发射电路和无线接收电路；
    所述第一逆变器的输入端连接第一可调电源；
    所述第二逆变器的输入端连接第二可调电源；
    所述第一逆变器的输出端连接所述无线发射电路的输入端；
    所述第二逆变器的输出端连接所述无线发射电路的输入端；
    所述无线发射电路通过无线方式将电能发射出去，所述无线接收电路通过无线方式接收所述无线发射电路发射的电能以给负载供电。
  15. 根据权利要求14所述的无线充电系统，其特征在于，所述无线发射电路包括发射补偿网络和发射线圈；所述无线接收电路包括接收补偿网络和接收线圈；
    所述发射补偿网络的输入端作为所述无线发射电路的输入端，所述发射补偿网络的输出端连接所述发射线圈；
    所述接收线圈连接所述接收补偿网络的输入端，所述接收补偿网络的输出端连接负载。
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EP3691104A4 (en) 2020-11-18
CN109698630B (zh) 2020-06-26
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