CN115085322A - Power supply system, energy storage converter and pre-charging method - Google Patents

Power supply system, energy storage converter and pre-charging method Download PDF

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Publication number
CN115085322A
CN115085322A CN202210784559.2A CN202210784559A CN115085322A CN 115085322 A CN115085322 A CN 115085322A CN 202210784559 A CN202210784559 A CN 202210784559A CN 115085322 A CN115085322 A CN 115085322A
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CN
China
Prior art keywords
power supply
circuit
inverter circuit
switch
switching power
Prior art date
Legal status (The legal status 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 status listed.)
Pending
Application number
CN202210784559.2A
Other languages
Chinese (zh)
Inventor
邓凯
申智
汪昌友
黄瑞
孙鹏鹏
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sungrow Power Supply Co Ltd
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Sungrow Power Supply Co Ltd
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Filing date
Publication date
Application filed by Sungrow Power Supply Co Ltd filed Critical Sungrow Power Supply Co Ltd
Priority to CN202210784559.2A priority Critical patent/CN115085322A/en
Publication of CN115085322A publication Critical patent/CN115085322A/en
Pending legal-status Critical Current

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    • 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
    • H02J7/007—Regulation of charging or discharging current or voltage
    • 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
    • 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
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00304—Overcurrent protection
    • 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
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • 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
    • H02J7/04—Regulation of charging current or voltage
    • H02J7/06—Regulation of charging current or voltage using discharge tubes or semiconductor devices
    • 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
    • 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
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc 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
    • H02M7/217—Conversion of ac power input into dc 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
    • 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
    • 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
    • H02M7/66—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal
    • H02M7/68—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters
    • H02M7/72—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/79—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with 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
    • H02M7/797—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output with 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The embodiment of the application discloses a power supply system, an energy storage converter and a pre-charging method, which comprises the following steps: an inverter circuit and a pre-charge circuit; the pre-charging circuit includes: the system comprises a rectification circuit, a switching power supply and a pre-charging branch circuit; the first end and the second end of the inverter circuit are respectively connected with the first end of the pre-charging branch circuit and the power grid; the pre-charging branch comprises a first switch and a first resistor which are connected in series; the first end of the rectifying circuit is connected with the second end of the inverter circuit, and the second end of the rectifying circuit is connected with the second end of the pre-charging branch circuit through a switching power supply; the second end of the pre-charging branch is connected with a direct-current power supply; when the input voltage of the inverter circuit is smaller than the first preset voltage, the first switch is closed, the rectifying circuit rectifies the alternating current into direct current and supplies the direct current to the switching power supply, and the switching power supply boosts the output voltage of the rectifying circuit and then pre-charges the first end of the inverter circuit. The switching power supply can boost voltage, the peak value of the direct current bus voltage is larger than the peak value of the alternating current voltage, and when the relay is closed, larger voltage impact cannot exist.

Description

Power supply system, energy storage converter and pre-charging method
Technical Field
The application relates to the technical field of power supplies, in particular to a power supply system, an energy storage converter and a pre-charging method.
Background
With the continuous development of new energy, the new energy field includes a Power Converter (PCS), which generally can be used as a bidirectional Converter, a dc side of which is connected to an energy storage battery, and an ac side of which is connected to a Power grid or a load. The energy storage converter can convert direct current output by the energy storage battery into alternating current to feed back to a power grid, and can also convert the alternating current into the direct current to charge the energy storage battery.
However, if the dc side of the energy storage converter is disconnected from the energy storage battery, the dc bus voltage on the dc side is 0, so that the dc bus needs to be charged, and when the dc bus voltage reaches a preset voltage, the relay between the energy storage converter and the power grid is controlled to be closed. However, the charging schemes of the prior art all have problems, and the surge voltage still exists when the relay is closed.
Disclosure of Invention
In order to solve the above problem, embodiments of the present application provide a power supply system, an energy storage converter, and a pre-charging method, which can reduce an impulse voltage when an ac-side relay is closed.
The present application provides a power supply system, comprising: an inverter circuit and a pre-charge circuit; the pre-charging circuit includes: the device comprises a rectifying circuit, a switching power supply and a pre-charging branch circuit;
the first end of the inverter circuit is used for being connected with the first end of the pre-charging branch circuit, and the second end of the inverter circuit is used for being connected with a power grid or a load; the pre-charging branch circuit at least comprises a first switch and a first resistor which are connected in series;
the first end of the rectifying circuit is connected with the second end of the inverter circuit, and the second end of the rectifying circuit is connected with the second end of the pre-charging branch circuit through a switching power supply; the second end of the pre-charging branch is used for connecting a direct-current power supply;
when the input voltage of the inverter circuit is smaller than the first preset voltage, the first switch is closed, the rectifying circuit is used for rectifying alternating current into direct current and supplying the direct current to the switching power supply, and the switching power supply is used for pre-charging the first end of the inverter circuit through the pre-charging branch circuit after boosting the output voltage of the rectifying circuit.
Preferably, the precharge circuit further includes: a second resistor;
the first end of the switching power supply is connected with the second end of the rectifying circuit, and the second end of the switching power supply is connected with the first end of the inverter circuit through a second resistor; the resistance value of the second resistor is larger than that of the first resistor;
when the input voltage of the inverter circuit is smaller than a second preset voltage value, the first switch is controlled to be switched off, and the switch power supply precharges the first end of the inverter circuit through the second resistor; when the input voltage of the inverter circuit is greater than the second preset voltage value and less than the first preset voltage value, the first switch is closed, and the switch power supply precharges the first end of the inverter circuit through the precharging branch circuit.
Preferably, the power supply system comprises a plurality of inverter circuits and a plurality of pre-charging circuits, wherein the inverter circuits correspond to the pre-charging circuits one to one;
the first ends of the inverter circuits are all used for connecting a direct-current power supply, and the second ends of the inverters are all used for connecting a power grid or a load;
each pre-charge circuit further includes: a diode;
the anode of the diode is connected with the switching power supply, and the cathode of the diode is connected with the first end of the inverter circuit.
Preferably, each of the precharge circuits further includes: a second switch;
the input end of the inverter circuit is connected with a direct-current power supply through a second switch;
the input voltage of the inverter circuit is greater than the first preset voltage, and the second switch is closed.
Preferably, each of the precharge circuits further includes: a third switch;
the positive input end of the inverter circuit is connected with the positive end of the direct-current power supply through the pre-charging branch circuit, and the negative input end of the inverter circuit is connected with the negative end of the direct-current power supply through the third switch.
Preferably, the power supply system further includes: the capacitor is connected between the second end of the pre-charging branch circuit and the first end of the inverter circuit;
the capacitor, the inverter circuit, the pre-charging branch circuit, the switching power supply and the rectifying circuit are all positioned in the energy storage converter; the rectifying circuit is a rectifying circuit in an auxiliary power supply of the energy storage converter.
Preferably, the rectifier circuit is an uncontrolled rectifier circuit comprising diodes.
The present application further provides an energy storage converter, including: an inverter circuit and a pre-charging circuit; the pre-charging circuit includes: the system comprises a rectification circuit, a switching power supply and a pre-charging branch circuit; the first end of the inverter circuit is used for being connected with the first end of the pre-charging branch circuit, and the second end of the inverter circuit is used for being connected with a power grid or a load; the pre-charging branch circuit at least comprises a first switch and a first resistor which are connected in series;
the first end of the rectifying circuit is connected with the second end of the inverter circuit, and the second end of the rectifying circuit is connected with the second end of the pre-charging branch circuit through a switching power supply; the second end of the pre-charging branch is used for connecting a direct-current power supply;
when the input voltage of the inverter circuit is smaller than the first preset voltage, the first switch is closed, the rectifying circuit is used for rectifying alternating current into direct current and supplying the direct current to the switching power supply, and the switching power supply is used for pre-charging the first end of the inverter circuit through the pre-charging branch circuit after boosting the output voltage of the rectifying circuit.
Preferably, the method further comprises the following steps: a second resistor;
the first end of the switching power supply is connected with the second end of the rectifying circuit, and the second end of the switching power supply is connected with the first end of the inverter circuit through a second resistor; the resistance value of the second resistor is larger than that of the first resistor;
when the input voltage of the inverter circuit is smaller than a second preset voltage value, the first switch is controlled to be switched off, and the switch power supply precharges the first end of the inverter circuit through the second resistor; when the input voltage of the inverter circuit is greater than the second preset voltage value and less than the first preset voltage value, the first switch is closed, and the switch power supply precharges the first end of the inverter circuit through the precharging branch circuit.
Preferably, the number of the energy storage converters is multiple, the input ends of the energy storage converters are all connected with a direct current power supply, and the output ends of the energy storage converters are all used for connecting a power grid or a load;
the pre-charging circuit in each energy storage converter further comprises: a diode;
the anode of the diode is connected with the switching power supply, and the cathode of the diode is connected with the first end of the inverter circuit.
Preferably, each of the precharge circuits further includes: a third switch;
the positive input end of the inverter circuit is connected with the positive end of the direct-current power supply through the pre-charging branch circuit, and the negative input end of the inverter circuit is connected with the negative end of the direct-current power supply through the third switch.
Preferably, the rectifying circuit is a rectifying circuit in an auxiliary power supply in the energy storage converter.
The present application provides a pre-charging method of a power supply system, the power supply system including: an inverter circuit and a pre-charge circuit; the pre-charging circuit includes: the device comprises a rectifying circuit, a switching power supply and a pre-charging branch circuit; the first end of the inverter circuit is used for being connected with the first end of the pre-charging branch circuit, and the second end of the inverter circuit is used for being connected with a power grid or a load; the pre-charging branch circuit at least comprises a first switch and a first resistor which are connected in series; the first end of the rectifying circuit is connected with the second end of the inverter circuit, and the second end of the rectifying circuit is connected with the second end of the pre-charging branch circuit through a switching power supply; the second end of the pre-charging branch is used for connecting a direct-current power supply;
the method comprises the following steps:
when the input voltage of the inverter circuit is smaller than a first preset voltage, the first switch is controlled to be closed, the rectifying circuit is used for rectifying alternating current into direct current and supplying the direct current to the switching power supply, and the switching power supply is used for pre-charging the first end of the inverter circuit through the pre-charging branch circuit after boosting the output voltage of the rectifying circuit.
Preferably, the precharge circuit further includes: a second resistor; the first end of the switching power supply is connected with the second end of the rectifying circuit, and the second end of the switching power supply is connected with the first end of the inverter circuit through a second resistor; the resistance value of the second resistor is larger than that of the first resistor;
switching power supply passes through the pre-charge branch road and for inverter circuit's first end pre-charge, specifically includes:
when the input voltage of the inverter circuit is smaller than a second preset voltage value, the first switch is controlled to be switched off, and the switch power supply precharges the first end of the inverter circuit through the second resistor;
when the input voltage of the inverter circuit is greater than the second preset voltage value and less than the first preset voltage value, the first switch is closed, and the switch power supply precharges the first end of the inverter circuit through the precharging branch circuit.
Therefore, the embodiment of the application has the following beneficial effects:
the power supply system provided by the application comprises an inverter circuit and a pre-charging circuit; the pre-charging circuit includes: the device comprises a rectifying circuit, a switching power supply and a pre-charging branch circuit; the first end of the inverter circuit is used for being connected with the first end of the pre-charging branch circuit, and the second end of the inverter circuit is used for being connected with a power grid or a load; the pre-charging branch circuit at least comprises a first switch and a first resistor which are connected in series; the first end of the rectifying circuit is connected with the second end of the inverter circuit, and the second end of the rectifying circuit is connected with the second end of the pre-charging branch circuit through a switching power supply; the second end of the pre-charging branch is used for connecting a direct-current power supply;
the application provides a switching power supply can step up, is about to be the output voltage of rectifier circuit and steps up the back and precharge for inverter circuit's input, can guarantee like this that the peak value of direct current bus voltage is greater than alternating voltage's peak value, and then when the relay of interchange side is closed, can not have voltage impact because of the voltage difference.
Drawings
FIG. 1 is a schematic diagram of a power supply system;
fig. 2 is a schematic diagram of a power supply system according to an embodiment of the present disclosure;
fig. 3 is a schematic diagram of another power supply system provided in an embodiment of the present application;
fig. 4 is a schematic diagram of a power supply system according to an embodiment of the present application;
fig. 5 is a schematic diagram of another power supply system provided in an embodiment of the present application;
fig. 6 is a schematic diagram of another power supply system provided in the embodiment of the present application;
fig. 7 is a schematic diagram of an energy storage converter according to an embodiment of the present application;
fig. 8 is a flowchart of a pre-charging method of a power supply system according to an embodiment of the present disclosure.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, an application scenario of the power supply system provided in the embodiments of the present application is described below with reference to the accompanying drawings.
The embodiment of the application does not specifically limit the application scenario of the inverter circuit, and can be applied to any power supply situation where one side is alternating current and the other side is direct current, such as an energy storage scenario, a photovoltaic scenario, a charger scenario, and the like.
For convenience of understanding, the application of the inverter circuit in an energy storage scenario is described as an example, an input end of the inverter circuit may be connected to an energy storage battery, and an output end of the inverter circuit is connected to a power grid.
In practical products, the inverter circuit is generally located on an inverter circuit board, and the input end of the inverter circuit is connected with a direct current bus capacitor, so that the inverter circuit further comprises a capacitor plate.
Referring to fig. 1, a schematic diagram of a power supply system is shown.
The power supply system comprises a capacitance plate 105, an inverter circuit board 104a and a pre-charging circuit 1000, wherein the pre-charging circuit comprises a resistor R, a rectifier bridge 101a and a switch 102. The pre-charging circuit further comprises a pre-charging branch, wherein the pre-charging branch comprises a resistor R1 and a switch K1 which are connected in series. In addition, a pass switch K2 for normal operation is also included.
The output end of the inverter circuit board 104a is connected with the power grid through two-stage relays connected in series. The two-stage relays are respectively K3 and K4. When the output end of the inverter circuit board 104a is connected with the power grid, K3 and K4 are both closed.
When the capacitor plate 105 is disconnected with the direct-current power supply, the scheme that the rectifier bridge 101 is connected with the resistor R in series in fig. 1 is adopted for pre-charging the capacitor plate 105, and during pre-charging, K1-1 is closed and K2-1 is opened; after the pre-charging is finished, K2-1 is closed, and K1-1 is opened. The maximum value of the DC bus voltage is smaller than the voltage peak value of the power grid, and a large surge voltage still exists when K3 and K4 are closed.
In order to reduce the voltage impact when the relay is closed, the embodiment of the present application provides a new pre-charging circuit, which is described in detail below with reference to the accompanying drawings.
Referring to fig. 2, the figure is a schematic diagram of a power supply system according to an embodiment of the present application.
The power supply system provided by the embodiment of the application comprises: an inverter circuit 104 and a precharge circuit; the pre-charging circuit includes: a rectifying circuit 101, a switching power supply 103 and a pre-charging branch circuit;
in this embodiment, the first end of the inverter circuit 104 is connected to the capacitor plate 105.
A first end of the inverter circuit 104 is used for connecting a first end of the pre-charging branch, and a second end of the inverter circuit 104 is used for connecting a power grid or a load; the pre-charging branch circuit at least comprises a first switch K1-1 and a first resistor R1-1 which are connected in series;
the first end of the rectifying circuit 101 is connected with the second end of the inverter circuit, and the second end of the rectifying circuit 101 is connected with the second end of the pre-charging branch circuit through the switching power supply 103; the second end of the pre-charging branch is used for connecting a direct-current power supply;
when the input voltage of the inverter circuit 104 is less than the first preset voltage, the first switch is closed, the rectifier circuit 101 is configured to rectify the alternating current into a direct current to be provided to the switching power supply 103, and the switching power supply 103 pre-charges the first end of the inverter circuit 104 through the pre-charging branch after boosting the output voltage of the rectifier circuit 101. When the voltage is precharged to a certain voltage, the direct current power supply is connected, so that overshoot voltage and overshoot current cannot be generated for a subsequent circuit due to too high voltage of the direct current power supply, and the safety of the subsequent circuit is protected.
The pre-charge circuit further includes: a second switch K2-1;
the input end of the inverter circuit is connected with a direct-current power supply through a second switch K2-1;
the input voltage of the inverter circuit is greater than the first preset voltage, and the second switch is closed.
Specifically, during pre-charging, K1-1 is closed, the rectifying circuit 101 takes power from the alternating current side, the power is rectified into direct current and is supplied to the input end of the switching power supply 103, the voltage of the switching power supply 103 is boosted and converted and then the input end of the capacitor plate 105 is charged through K1-1 and R1-1, the voltage of the capacitor plate 105 is increased along with the increase of the charging time, after the pre-charging meets the requirement, the second switch K2-1 can be controlled to be closed, at the moment, the K1-1 can be controlled to be opened, or the K1-1 can be not controlled, and when the K2-1 is closed, the K1-1 and the R1-1 of the pre-charging branch are automatically bypassed.
The embodiment of the present application does not specifically limit the specific implementation form of the switching power supply 103, and for example, a flyback switching power supply may be used. Specifically, the switching power supply 103 may boost the output voltage of the rectifying circuit 101 and provide the boosted output voltage to the input end of the capacitor plate 105, and the switch in the switching power supply 103 provided in the embodiment of the present application is controlled by a weak current signal, and does not need a high voltage switch or a high voltage relay. In addition, the transformer in the switching power supply 103 is a high-frequency transformer, and is not a line-frequency transformer, so that the volume and cost of the whole pre-charging circuit can be effectively reduced by using the high-frequency transformer. In addition, since no transformer is present in fig. 1, the peak value of the dc bus voltage is smaller than the peak value of the ac voltage. The switching power supply 103 in the embodiment of the present application may be a high frequency power supply, and may also boost the output voltage of the rectifying circuit, that is, pre-charge the input terminal of the inverter circuit after boosting, so as to ensure that the peak value of the dc bus voltage is greater than the peak value of the ac voltage, and further when the relay on the ac side is closed, there is no voltage impact due to the voltage difference.
In addition, in order to reduce the cost, the rectifying circuit may be a rectifying circuit in an auxiliary power supply in the power electronic device in which the inverter circuit is located, for example, when the power electronic device is an energy storage converter, the energy storage converter includes an auxiliary power supply, and the auxiliary power supply is used for supplying power to the control circuit, for example, the auxiliary power supply can generally output a voltage of 24V or 12V. The rectifier circuit in the embodiment of the application can directly adopt the uncontrolled rectifier circuit in the auxiliary power supply, and the rectifier circuit does not need to be additionally arranged, so that the hardware overhead can be saved, and the size of a hardware circuit is reduced. It should be understood that the switch tubes in the non-controlled rectifying circuit are all diodes, and are not required to be controlled, so that the control difficulty can be reduced.
Taking the field of energy storage as an example, the dc power source is an energy storage battery, see fig. 3, which is a schematic diagram of another power supply system provided in the embodiment of the present application.
The power supply system provided in fig. 3 includes a power storage converter PCS, wherein the capacitor plate 105, the inverter circuit 104, the rectifier circuit 101, the switching power supply 103, and the pre-charge circuit are all located inside the power storage converter PCS.
That is, the positive input terminal of the capacitor plate 105 is connected to the positive terminal BAT of the battery through the pre-charge branch, and the negative input terminal of the capacitor plate 105 is connected to the negative terminal BAT of the battery. For example, when the battery voltage is low or the battery is disconnected from capacitor plate 105, the pre-charge circuit takes power from the ac side to charge the input of capacitor plate 105, i.e., to charge the dc bus capacitor.
In addition, in order to effectively reduce the rated power of the switching power supply, the precharge circuit provided in the embodiment of the present application further includes a second resistor, which is described in detail below with reference to the accompanying drawings.
Referring to fig. 4, the figure is a schematic diagram of a power supply system provided in an embodiment of the present application.
The power supply system provided in this embodiment is described by taking the energy storage converter PCS as an example, and the pre-charging circuit further includes: a second resistor R2-1;
the first end of the switching power supply 103 is connected with the second end of the rectifying circuit, and the second end of the switching power supply 103 is connected with the first end of the inverter circuit 104 through a second resistor R2-1; the resistance value of the second resistor R2-1 is larger than that of the first resistor R1-1;
when the input voltage of the inverter circuit 104 is smaller than a second preset voltage value, the first switch K1-1 is controlled to be switched off, and the switching power supply 103 pre-charges the first end of the inverter circuit 104 through a second resistor R2-1; when the input voltage of the inverter circuit 104 is greater than the second preset voltage value and less than the first preset voltage value, the first switch K1-1 is closed, and the switching power supply 103 precharges the first end of the inverter circuit 104 through the precharge branch.
For example, the ac voltage of the grid is 800V for example, and the output voltage boosted by the switching power supply 103 may be 1300V. The resistance value of R2-1 can be selected to be integral multiple of that of R1-1, for example, R1-1 can be 2k or 3k ohm, and R2-1 can be about 20k ohm. The above is merely an example, as long as the resistance of R2-1 is greater than that of R1-1.
The pre-charging circuit provided by the embodiment of the application is designed to be double-path output, namely, one path of the pre-charging circuit is directly connected with the positive end of a battery, and the other path of the pre-charging circuit is connected with the input end of a capacitor plate through a second resistor connected in series. The power supply system provided by this embodiment can use the pre-charging resistor with a larger resistance value to limit the current, that is, to limit the current through the second resistor, in order to avoid an excessive inrush current and an excessive power required by the switching power supply when pre-charging is started. When the voltage is charged to a certain value, such as a first preset voltage, the current can be limited by switching to a first smaller resistor. Therefore, when the switch is switched on for pre-charging, the power required by the switching power supply can be reduced, and the reduction of the size and the cost of the switching power supply is facilitated.
It should be noted that the fans inside the energy storage converter need to be guaranteed not to run before the ac side two-stage series relays (K3 and K4) are not closed, and thus there is enough power to support other loads inside the energy storage converter.
In addition, in an actual product, in order to improve the capacity of the whole power supply system, a plurality of inverter circuits can be included, and the inverter circuits are connected in parallel to connect a power grid or a load. The case of a plurality of inverter circuits is described below.
Referring to fig. 5, the schematic diagram of another power supply system provided in the embodiment of the present application is shown.
For a power supply system with a plurality of inverter circuits connected in parallel, if the output voltage time of the switching power supply is inconsistent when the direct current sides are connected in parallel, part of the switching power supply can be overloaded and run until the voltage of the switching power supply is pulled down, so that the switching power supply is shut down. Therefore, in order to solve the above problem caused by time inconsistency, the precharge circuit in the power supply system provided in the embodiment of the present application further includes a diode, and an output port of the switching power supply is connected in series with an anti-reverse diode, so as to avoid the generation of an overload loop.
As shown in fig. 5, the power supply system includes a plurality of inverter circuits and a plurality of pre-charge circuits, and the inverter circuits and the pre-charge circuits correspond to each other one to one;
the first ends of the inverter circuits are all used for connecting a direct-current power supply, and the second ends of the inverters are all used for connecting a power grid or a load;
each pre-charge circuit further includes: a diode;
the anode of the diode is connected with the switching power supply, and the cathode of the diode is connected with the first end of the inverter circuit.
The number of the inverter circuits connected in parallel is not particularly limited in this embodiment, and is, for example, n, where n is an integer greater than or equal to 2. In FIG. 5, the power supply system includes n PCS, namely PCS-1 to PCS-n. The devices and connections in PCS-1 to PCS-n are the same, and PCS-1 is described first below.
The output end of the capacitor plate 1 is connected with the first end of the inverter circuit 1, and the second end of the inverter circuit 1 is connected with a power grid through two-stage relays K3-1 and K4-1 which are connected in series. The first end of the rectifying circuit 101 is connected to a power grid, the second end of the rectifying circuit 101 is connected to the first end of the switching power supply 103, the second end of the switching power supply 103 is connected to the positive input end of the capacitor plate 1 through a second resistor R2-1 and a diode D1-1, the second end of the switching power supply 103 is connected to the positive terminal BAT + of the battery through a diode D2-1, and the K1-1, the K2-1 and the R1-1 of the pre-charging branch are the same as those in fig. 4 and are not described herein again.
Similarly, the output end of a capacitor plate n in the PCS-n is connected with the first end of an inverter circuit n, and the second end of the inverter circuit n is connected with a power grid through two-stage relays K3-n and K4-n which are connected in series. The first end of the rectifying circuit 10n is connected with a power grid, the second end of the rectifying circuit 10n is connected with the first end of the switching power supply 103n, the second end of the switching power supply 103n is connected with the positive input end of the capacitor plate n through a second resistor R2-n and a diode D1-n, the second end of the switching power supply 103n is connected with the positive terminal BAT + of the battery through a diode D2-n, the pre-charging branch comprises K1-n and R1-n which are connected in series, the first end of the capacitor plate n is connected with BAT + through K1-n and R1-n which are connected in series, and the first end of the capacitor plate n is connected with BAT + through K2-n.
Since the working principle of the precharge circuit has been described in the above embodiments, the present embodiment mainly describes the added anti-reverse diode, and when a plurality of PCS are connected in parallel, if the time of the output voltage of the switching power supply in each PCS is not consistent, part of the switching power supply may be overloaded to operate until the voltage of the switching power supply is pulled down, and the switching power supply is turned off. Therefore, in order to prevent the switching power supply from being overloaded when the output voltages of the switching power supplies do not coincide in time, a diode is connected to the second terminal of the switching power supply, and the reverse blocking function is performed due to the presence of the anti-reverse diode, that is, the switching power supply 103 does not become a load of the switching voltage 103n, and the switching power supply 103n does not become a load of the switching power supply 103.
Since the output of the switching power supply comprises two outputs, each output is connected with a diode, for example, the PCS1 comprises D1-1 and D2-1.
In addition, in order to avoid the situation that when a plurality of PCS are connected in parallel, the output voltages of the switching power supplies are not consistent, which results in overload of a part of the switching power supplies, the embodiment of the present application further provides another solution, see fig. 6, which is a schematic diagram of another power supply system provided by the embodiment of the present application.
In the power supply system provided in this embodiment, each of the precharge circuits further includes: a third switch;
the positive input end of the inverter circuit is connected with the positive end of the direct-current power supply through the pre-charging branch circuit, and the negative input end of the inverter circuit is connected with the negative end of the direct-current power supply through the third switch.
As can be seen from comparing fig. 5 and 6, no anti-reverse diode is provided in fig. 6, the input terminals of the capacitor plate include a positive input terminal and a negative input terminal, a third switch is added to the negative input terminal of the capacitor plate, a third switch K5-1 is added to PCS1, and a third switch K5-n is added to PCSn. That is, the negative input terminal of the capacitor plate 1 is connected to BAT through the third switch K5-1, and the negative input terminal of the capacitor plate n is connected to BAT through the third switch K5-n.
The power supply system provided by the embodiment of the application can avoid overload of the switching power supply by controlling the third switch, for example, the output voltage of the switching power supply can be detected, and when the output voltage of the switching power supply is greater than a preset target voltage, the third switch is controlled to be closed, otherwise, the third switch is controlled to be opened.
Comparing fig. 5 and fig. 6, the problem of overload of the switching power supply can be solved, and the scheme of fig. 5 is relatively simpler, and because the diode automatically realizes reverse cut-off, a controller is not needed for control.
It should be understood that each switch in the power supply system provided by the embodiments of the present application requires a controller to drive to control the state of the switch, for example, the controller sends a driving signal to the switch. The type of the switch is not particularly limited in the present application, and all the switches are controllable switch tubes. For example, the controllable switch tube may be of any one of the following types: relays, Insulated Gate Bipolar Transistors (IGBTs), Metal Oxide Semiconductor field Effect transistors (MOSFETs, hereinafter referred to as MOS transistors), SiC MOSFETs (Silicon Carbide field Effect transistors), and the like. When the switching transistor is an MOS transistor, the switching transistor may specifically be a PMOS transistor or an NMOS transistor, which is not specifically limited in this application embodiment.
Based on the power supply system provided by the above embodiment, the embodiment of the present application further provides an energy storage converter, which is described in detail below with reference to the accompanying drawings.
Referring to fig. 7, the figure is a schematic diagram of an energy storage converter according to an embodiment of the present application.
The energy storage converter that this embodiment provided includes: an inverter circuit 104 and a precharge circuit; the pre-charging circuit includes: a rectifying circuit 101, a switching power supply 103 and a pre-charging branch 701; a first end of the inverter circuit 104 is used for connecting a first end of the pre-charging branch 701, and a second end of the inverter circuit 104 is used for connecting a power grid or a load; the pre-charging branch 701 at least comprises a first switch and a first resistor which are connected in series;
a first end of the rectifying circuit 101 is connected with a second end of the inverter circuit 104, and a second end of the rectifying circuit 101 is connected with a second end of the pre-charging branch 701 through the switching power supply 103; the second end of the pre-charging branch 701 is used for connecting a direct-current power supply;
when the input voltage of the inverter circuit 104 is less than the first preset voltage, the first switch is closed, the rectifier circuit 101 is configured to rectify the ac power into the dc power and provide the dc power to the switching power supply 103, and the switching power supply 103 precharges the first end of the inverter circuit 104 through the precharge branch 701.
The embodiment of the present application does not specifically limit the specific implementation form of the switching power supply 103, and for example, a flyback switching power supply may be used. Specifically, the switching power supply 103 may boost the output voltage of the rectifying circuit 101 and provide the boosted output voltage to the input end of the capacitor plate 105, and the switch in the switching power supply 103 provided in the embodiment of the present application is controlled by a weak current signal, and does not need a high voltage switch or a high voltage relay. In addition, the transformer in the switching power supply 103 is a high-frequency transformer, and is not a line-frequency transformer, so that the volume and cost of the whole pre-charging circuit can be effectively reduced by using the high-frequency transformer. In addition, since no transformer is present in fig. 1, the peak value of the dc bus voltage is smaller than the peak value of the ac voltage. The switching power supply 103 in the embodiment of the present application may be a high frequency power supply, and may also boost voltage, that is, the output voltage of the rectifying circuit may be boosted to precharge the input terminal of the inverter circuit, so as to ensure that the peak value of the dc bus voltage is greater than the peak value of the ac voltage, and further, when the relay on the ac side is closed, there is no voltage impact due to the voltage difference.
Energy storage converter still includes: a second resistor;
the first end of the switching power supply is connected with the second end of the rectifying circuit, and the second end of the switching power supply is connected with the first end of the inverter circuit through a second resistor; the resistance value of the second resistor is larger than that of the first resistor;
when the input voltage of the inverter circuit is smaller than a second preset voltage value, the first switch is controlled to be switched off, and the switch power supply precharges the first end of the inverter circuit through the second resistor; when the input voltage of the inverter circuit is greater than the second preset voltage value and less than the first preset voltage value, the first switch is closed, and the switch power supply precharges the first end of the inverter circuit through the precharging branch circuit.
When the number of the energy storage converters is multiple, the input ends of the energy storage converters are all connected with a direct-current power supply, and the output ends of the energy storage converters are all used for connecting a power grid or a load;
the pre-charging circuit in each energy storage converter further comprises: a diode;
the anode of the diode is connected with the switching power supply, and the cathode of the diode is connected with the first end of the inverter circuit.
Each pre-charge circuit further includes: a third switch;
the positive input end of the inverter circuit is connected with the positive end of the direct-current power supply through the pre-charging branch circuit, and the negative input end of the inverter circuit is connected with the negative end of the direct-current power supply through the third switch.
The rectifying circuit is a rectifying circuit in an auxiliary power supply in the energy storage converter.
For the specific operating principle and the internal connection relationship of the energy storage converter, reference may be made to the description of the above embodiment of the power supply system, and details are not described herein again.
Based on the power supply system and the energy storage converter provided by the above embodiments, the embodiments of the present application further provide a pre-charging method for the power supply system, which is described in detail below with reference to the accompanying drawings.
Referring to fig. 8, the figure is a flowchart of a pre-charging method of a power supply system according to an embodiment of the present application.
In the precharge method of the power supply system provided in this embodiment, the power supply system includes: an inverter circuit and a pre-charge circuit; the pre-charging circuit includes: the device comprises a rectifying circuit, a switching power supply and a pre-charging branch circuit; the first end of the inverter circuit is used for being connected with the first end of the pre-charging branch circuit, and the second end of the inverter circuit is used for being connected with a power grid or a load; the pre-charging branch circuit at least comprises a first switch and a first resistor which are connected in series; the first end of the rectifying circuit is connected with the second end of the inverter circuit, and the second end of the rectifying circuit is connected with the second end of the pre-charging branch circuit through a switching power supply; the second end of the pre-charging branch is used for connecting a direct-current power supply;
the method comprises the following steps:
s801: detecting an input voltage of the inverter circuit;
s802: when the input voltage of the inverter circuit is judged to be smaller than the first preset voltage, the first switch is controlled to be closed, the rectifying circuit is used for rectifying alternating current into direct current and supplying the direct current to the switching power supply, and the switching power supply precharges the first end of the inverter circuit through the precharging branch.
The pre-charge circuit further includes: a second resistor; the first end of the switching power supply is connected with the second end of the rectifying circuit, and the second end of the switching power supply is connected with the first end of the inverter circuit through a second resistor; the resistance value of the second resistor is larger than that of the first resistor;
switching power supply passes through the pre-charge branch road and for inverter circuit's first end pre-charge, specifically includes:
when the input voltage of the inverter circuit is smaller than a second preset voltage value, the first switch is controlled to be switched off, and the switch power supply precharges the first end of the inverter circuit through the second resistor;
when the input voltage of the inverter circuit is greater than the second preset voltage value and less than the first preset voltage value, the first switch is closed, and the switch power supply precharges the first end of the inverter circuit through the precharging branch circuit.
According to the method, the switching power supply can be boosted, namely the output voltage of the rectifying circuit is boosted and then is pre-charged to the input end of the inverter circuit, so that the peak value of the direct-current bus voltage is greater than the peak value of the alternating-current voltage, and voltage impact caused by voltage difference can be avoided when the relay on the alternating-current side is closed.
It should be noted that, in the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. For the system or the device disclosed by the embodiment, the description is simple because the system or the device corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.

Claims (14)

1. A power supply system, comprising: an inverter circuit and a pre-charging circuit; the pre-charge circuit includes: the device comprises a rectifying circuit, a switching power supply and a pre-charging branch circuit;
the first end of the inverter circuit is used for being connected with the first end of the pre-charging branch circuit, and the second end of the inverter circuit is used for being connected with a power grid or a load; the pre-charging branch circuit at least comprises a first switch and a first resistor which are connected in series;
the first end of the rectifying circuit is connected with the second end of the inverter circuit, and the second end of the rectifying circuit is connected with the second end of the pre-charging branch circuit through the switching power supply; the second end of the pre-charging branch is used for connecting a direct-current power supply;
when the input voltage of the inverter circuit is smaller than a first preset voltage, the first switch is closed, the rectifying circuit is used for rectifying alternating current into direct current and supplying the direct current to the switching power supply, and the switching power supply pre-charges the first end of the inverter circuit through the pre-charging branch circuit after boosting the output voltage of the rectifying circuit.
2. The power supply system of claim 1, wherein the pre-charge circuit further comprises: a second resistor;
the first end of the switching power supply is connected with the second end of the rectifying circuit, and the second end of the switching power supply is connected with the first end of the inverter circuit through the second resistor; the resistance value of the second resistor is larger than that of the first resistor;
when the input voltage of the inverter circuit is smaller than a second preset voltage value, the first switch is controlled to be switched off, and the switch power supply pre-charges the first end of the inverter circuit through the second resistor; when the input voltage of the inverter circuit is greater than the second preset voltage value and less than the first preset voltage, the first switch is closed, and the switch power supply precharges the first end of the inverter circuit through the precharge branch.
3. The power supply system according to claim 1 or 2, wherein the power supply system includes a plurality of inverter circuits and a plurality of precharge circuits, the inverter circuits and the precharge circuits corresponding to one another;
the first ends of the inverter circuits are all used for being connected with the direct-current power supply, and the second ends of the inverters are all used for being connected with a power grid or a load;
each of the precharge circuits further includes: a diode;
the anode of the diode is connected with the switching power supply, and the cathode of the diode is connected with the first end of the inverter circuit.
4. The power supply system of claim 3, wherein each of the pre-charge circuits further comprises: a second switch;
the input end of the inverter circuit is connected with the direct-current power supply through the second switch;
the input voltage of the inverter circuit is greater than a first preset voltage, and the second switch is closed.
5. The power supply system of claim 4, wherein each of the pre-charge circuits further comprises: a third switch;
the positive input end of the inverter circuit is connected with the positive end of the direct-current power supply through the pre-charging branch circuit, and the negative input end of the inverter circuit is connected with the negative end of the direct-current power supply through the third switch.
6. The power supply system according to any one of claims 1 to 5, characterized in that the power supply system further comprises: the capacitor is connected between the second end of the pre-charging branch circuit and the first end of the inverter circuit;
the capacitor, the inverter circuit, the pre-charging branch circuit, the switching power supply and the rectifying circuit are all positioned in the energy storage converter; the rectifying circuit is a rectifying circuit in an auxiliary power supply of the energy storage converter.
7. The power supply system according to any one of claims 1 to 6, wherein the rectifying circuit is an uncontrolled rectifying circuit comprising a diode.
8. An energy storage converter, comprising: an inverter circuit and a pre-charge circuit; the pre-charge circuit includes: the device comprises a rectifying circuit, a switching power supply and a pre-charging branch circuit; the first end of the inverter circuit is used for being connected with the first end of the pre-charging branch circuit, and the second end of the inverter circuit is used for being connected with a power grid or a load; the pre-charging branch circuit at least comprises a first switch and a first resistor which are connected in series;
the first end of the rectifying circuit is connected with the second end of the inverter circuit, and the second end of the rectifying circuit is connected with the second end of the pre-charging branch circuit through the switching power supply; the second end of the pre-charging branch is used for connecting a direct-current power supply;
when the input voltage of the inverter circuit is smaller than a first preset voltage, the first switch is closed, the rectifying circuit is used for rectifying alternating current into direct current and supplying the direct current to the switching power supply, and the switching power supply pre-charges the first end of the inverter circuit through the pre-charging branch circuit after boosting the output voltage of the rectifying circuit.
9. The energy storage converter according to claim 8, further comprising: a second resistor;
the first end of the switching power supply is connected with the second end of the rectifying circuit, and the second end of the switching power supply is connected with the first end of the inverter circuit through the second resistor; the resistance value of the second resistor is larger than that of the first resistor;
when the input voltage of the inverter circuit is smaller than a second preset voltage value, the first switch is controlled to be switched off, and the switch power supply pre-charges the first end of the inverter circuit through the second resistor; when the input voltage of the inverter circuit is greater than the second preset voltage value and less than the first preset voltage, the first switch is closed, and the switch power supply precharges the first end of the inverter circuit through the precharge branch.
10. The energy storage converter according to claim 8 or 9, wherein there are a plurality of energy storage converters, the input ends of the plurality of energy storage converters are connected to the dc power source, and the output ends of the plurality of energy storage converters are connected to a grid or a load;
the pre-charging circuit in each of the energy storage converters further comprises: a diode;
the anode of the diode is connected with the switching power supply, and the cathode of the diode is connected with the first end of the inverter circuit.
11. The energy storage converter according to claim 10, wherein each of the pre-charging circuits further comprises: a third switch;
the positive input end of the inverter circuit is connected with the positive end of the direct-current power supply through the pre-charging branch circuit, and the negative input end of the inverter circuit is connected with the negative end of the direct-current power supply through the third switch.
12. The energy storage converter according to any of claims 8-11, wherein said rectifying circuit is a rectifying circuit in an auxiliary power supply in said energy storage converter.
13. A pre-charging method of a power supply system, the power supply system comprising: an inverter circuit and a pre-charge circuit; the pre-charge circuit includes: the device comprises a rectifying circuit, a switching power supply and a pre-charging branch circuit; the first end of the inverter circuit is used for being connected with the first end of the pre-charging branch circuit, and the second end of the inverter circuit is used for being connected with a power grid or a load; the pre-charging branch circuit at least comprises a first switch and a first resistor which are connected in series; the first end of the rectifying circuit is connected with the second end of the inverter circuit, and the second end of the rectifying circuit is connected with the second end of the pre-charging branch circuit through the switching power supply; the second end of the pre-charging branch is used for connecting a direct-current power supply;
the method comprises the following steps:
when the input voltage of the inverter circuit is smaller than a first preset voltage, the first switch is controlled to be closed, the rectifying circuit is used for rectifying alternating current into direct current and supplying the direct current to the switching power supply, and the first end of the inverter circuit is precharged through the precharging branch circuit after the output voltage of the rectifying circuit is boosted by the switching power supply.
14. The precharge method as claimed in claim 13, wherein the precharge circuit further comprises: a second resistor; the first end of the switching power supply is connected with the second end of the rectifying circuit, and the second end of the switching power supply is connected with the first end of the inverter circuit through the second resistor; the resistance value of the second resistor is larger than that of the first resistor;
the switching power supply is through the pre-charge branch road is the first end pre-charge of inverter circuit specifically includes:
when the input voltage of the inverter circuit is smaller than a second preset voltage value, the first switch is controlled to be switched off, and the switch power supply pre-charges the first end of the inverter circuit through the second resistor;
when the input voltage of the inverter circuit is greater than the second preset voltage value and less than the first preset voltage value, the first switch is closed, and the switch power supply precharges the first end of the inverter circuit through the precharging branch.
CN202210784559.2A 2022-07-05 2022-07-05 Power supply system, energy storage converter and pre-charging method Pending CN115085322A (en)

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CN202210784559.2A CN115085322A (en) 2022-07-05 2022-07-05 Power supply system, energy storage converter and pre-charging method

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