Power conversion circuit, control method thereof, and computer readable storage medium

Abstract

The application provides an electric energy conversion circuit, a control method thereof and a computer readable storage medium. The electric energy conversion circuit comprises a direct current power port, a direct current-alternating current conversion circuit, a plurality of voltage reduction chopper circuits, a detection circuit and a controller. The direct current-alternating current conversion circuit comprises a plurality of commutation switch tubes. Each voltage reduction chopper circuit comprises a chopper switch tube and a first inductor. The controller is used for judging whether the circuit generates an electric arc according to a detection signal, controlling each chopper switch tube and each commutation switch tube to be turned off in a first arc extinguishing period after it is determined that the electric arc is generated, so that each first inductor releases part of energy to the direct current power port and the remaining part of energy, and controlling each chopper switch tube to be turned off and each commutation switch tube to be turned on in a second arc extinguishing period after it is determined that the electric energy conversion circuit generates the electric arc, so that each first inductor continues to flow through the turned-on plurality of commutation switch tubes, and then each first inductor latches the remaining part of energy.

Description

Technical Field

[0001] This application relates to the field of electronic circuit protection, and in particular to an electrical energy conversion circuit and its control method, as well as a computer-readable storage medium. Background Technology

[0002] The H-bridge circuit is a typical DC motor control circuit. It is named "H-bridge" because its circuit shape resembles the letter H. The H-bridge circuit inverts DC power into AC power of a certain frequency or a variable frequency by opening and closing a switch, which can be used to drive AC equipment.

[0003] H-bridge circuits can be used in motor drive circuits and radio frequency power supplies. Existing H-bridge circuits typically include four switching transistors, forming two bridge arms connected in parallel between a DC power supply. These four transistors work together to convert the DC power supplied by the DC power supply into AC power. However, existing H-bridge circuits cannot output a stepped waveform and have poor arc suppression capabilities. Summary of the Invention

[0004] In view of this, the main purpose of this application is to propose an energy conversion circuit and its control method, as well as a computer-readable storage medium, in order to solve the problems that the existing H-bridge circuit cannot output a stepped wave and has poor arc suppression capability.

[0005] To achieve the above objectives, a first aspect of this application provides a power conversion circuit, comprising a DC power port, a DC-AC conversion circuit, multiple buck chopper circuits, a detection circuit, and a controller. The DC power port receives a first DC voltage. The DC-AC conversion circuit includes a DC input port, an AC output port, and multiple commutator switches, each of which includes a control terminal. Each buck chopper circuit is electrically connected between the DC power port and the DC input port of the DC-AC conversion circuit. Each buck chopper circuit can receive the first DC voltage provided by the DC power port and convert the first DC voltage to a second DC voltage. Each buck chopper circuit includes a chopper switch and a first inductor, the chopper switch including a control terminal. The DC input port of the DC-AC conversion circuit receives the second DC voltage, and the DC-AC conversion circuit can convert the received second DC voltage into an AC voltage and output the AC voltage through the AC output port. The voltage conversion times of the multiple buck chopper circuits are staggered. The detection circuit is electrically connected to the DC-AC conversion circuit. The detection circuit detects the AC voltage or AC current output by the DC-AC conversion circuit and outputs a corresponding detection signal, which is either a current signal or a voltage signal. The controller is electrically connected to the detection circuit, the control terminals of each of the chopper switches, and the control terminals of each of the commutator switches. The controller receives the detection signal output by the detection circuit and determines whether the power conversion circuit generates an arc based on the detection signal. During the first arc-extinguishing period after determining that the power conversion circuit has generated an arc, the controller controls each of the chopper switches and each of the commutator switches to disconnect, causing the DC-AC conversion circuit and the multiple buck chopper circuits to stop power conversion. This also causes each of the first inductors to release a portion of its energy to the DC power port, leaving some energy remaining. The controller is further configured to, during a second arc-extinguishing period after determining that an arc has been generated in the power conversion circuit, control all chopper switches to disconnect and control all commutator switches to turn on, so that each first inductor continues to flow through the multiple turned-on commutator switches, thereby causing each first inductor to latch the remaining energy. The start time of the second arc-extinguishing period is the end time of the first arc-extinguishing period.

[0006] The power conversion circuit provided in this application can adjust the amplitude of the AC voltage through multiple step-down chopper circuits, thereby achieving stepped waves with different output amplitudes suitable for different loads. Furthermore, during the first arc-extinguishing period after an arc is detected, the power conversion circuit controls all the chopper switches and commutator switches to be disconnected, causing the DC-AC conversion circuit and the multiple step-down chopper circuits to stop power conversion. This allows each first inductor to release a portion of its energy to the DC power port, leaving a remaining portion. During the second arc-extinguishing period after an arc is detected in the power conversion circuit, the circuit controls all the chopper switches to be disconnected and all the commutator switches to be turned on, allowing each first inductor to continue flowing through the turned-on commutator switches. This allows each first inductor to latch the remaining energy. On the one hand, during the first arc-extinguishing period, the DC-AC conversion circuit... The multiple buck chopper circuits all stop power conversion, which can disconnect the circuit in time to prevent the arc from intensifying further. Furthermore, allowing each first inductor to release some energy ensures that the current remains below the safe current threshold, protecting the components in the circuit. On the other hand, during the second arc-extinguishing period, allowing each first inductor to freewheel through the multiple conducting commutator switches allows each first inductor to latch some energy. Therefore, when the power conversion circuit restarts after arc extinguishing, the current in each first inductor does not need to rise from zero, allowing the load current to quickly rise to the stable operating current. This not only saves energy but also makes the power conversion circuit start up more smoothly, avoiding secondary arcing due to restarting.

[0007] A second aspect of this application also provides a control method for a power conversion circuit, the power conversion circuit including a DC power supply port, a DC-AC conversion circuit, multiple buck chopper circuits, and a detection circuit. The DC power supply port is used to receive a first DC voltage. The DC-AC conversion circuit includes a DC input port, an AC output port, and multiple commutator switches, each of which includes a control terminal. Each buck chopper circuit is electrically connected between the DC power supply port and the DC input port of the DC-AC conversion circuit. Each buck chopper circuit can receive the first DC voltage provided by the DC power supply port and convert the first DC voltage to a second DC voltage. Each buck chopper circuit includes a chopper switch and a first inductor, the chopper switch including a control terminal. The DC input port of the DC-AC conversion circuit is used to receive the second DC voltage, and the DC-AC conversion circuit can convert the received second DC voltage into an AC voltage and output the AC voltage through the AC output port. The voltage conversion times of the multiple buck chopper circuits are staggered. The detection circuit is electrically connected to the AC output port of the DC-AC conversion circuit. The detection circuit is used to detect the AC voltage or AC current output by the DC-AC conversion circuit and output a corresponding detection signal, which is a current signal or a voltage signal.

[0008] The control method for the power conversion circuit includes: controlling the plurality of buck chopper circuits to convert the first DC voltage into the second DC voltage, and controlling the DC-AC conversion circuit to convert the second DC voltage into an AC voltage with a period of a preset working cycle, and outputting the AC voltage through the AC output port; acquiring the detection signal; determining whether the power conversion circuit generates an electric arc based on the detection signal; if it is determined that the power conversion circuit has not generated an electric arc, then continuing to control the plurality of buck chopper circuits to convert the first DC voltage into the second DC voltage, and controlling the DC-AC conversion circuit to convert the second DC voltage into an AC voltage with a period of a preset working cycle, and outputting the AC voltage through the AC output port; and, if it is determined that the power conversion circuit has generated an electric arc, ... Then, an arc-extinguishing control process is executed; wherein, the arc-extinguishing control process includes: during a first arc-extinguishing period after the power conversion circuit generates an arc, controlling all the chopper switches and all the commutator switches to be disconnected, so that the DC-AC conversion circuit and the plurality of buck chopper circuits stop power conversion, and causing each first inductor to release part of its energy to the DC power supply port and retain some energy; and during a second arc-extinguishing period after the power conversion circuit generates an arc, controlling all the chopper switches to be disconnected, and controlling all the commutator switches to be turned on, so that each first inductor continues current through the turned-on plurality of commutator switches, thereby causing each first inductor to latch the remaining energy; wherein, the start time of the second arc-extinguishing period is the end time of the first arc-extinguishing period.

[0009] A third aspect of this application also provides a computer-readable storage medium storing executable instructions that, when executed by a processor, implement the control method for the power conversion circuit described in the second aspect above.

[0010] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the power conversion circuit provided in the embodiments of this application;

[0012] Figure 2 for Figure 1 The timing diagram of the control signals output by the controller in the process of executing the arc extinguishing control procedure;

[0013] Figure 3 for Figure 1 The diagram shows the current flow direction of the power conversion circuit during the first and third arc-extinguishing periods.

[0014] Figure 4 for Figure 1 The diagram shows the current flow direction of the power conversion circuit during the second arc extinguishing period.

[0015] Figure 5 for Figure 1 The diagram shows the current waveform of the first inductor L11 when the power conversion circuit executes the arc extinguishing control process.

[0016] Figure 6 A flowchart illustrating the control method for the power conversion circuit provided in the embodiments of this application;

[0017] Figure 7 for Figure 6 The first detailed flowchart for step 64;

[0018] Figure 8 for Figure 6 The second detailed flowchart for step 64.

[0019] The annotations in the attached figures are explained as follows:

[0020] Power conversion circuit 100

[0021] Load device 200

[0022] DC power port 10

[0023] 20 step-down chopper circuit

[0024] DC-AC converter circuit 30

[0025] First power supply terminal S+

[0026] Second power supply terminal S-

[0027] DC input port 31

[0028] First input terminal 311

[0029] Second input terminal 312

[0030] Zener capacitors C1 and C2

[0031] First diodes D11 and D12

[0032] First inductors L11, L12

[0033] Chopper switching transistors M11 and M12

[0034] Second diode D2

[0035] Third diode D3

[0036] AC output port 32

[0037] First output terminal 321

[0038] Second output terminal 322

[0039] First commutator switch Q1

[0040] Second commutator switch Q2

[0041] Third commutator switch Q3

[0042] Fourth commutator switch Q4

[0043] Load connection port 40

[0044] Detection circuit 50

[0045] Controller 60

[0046] Second inductors L21, L22, L23

[0047] Preset working cycle T

[0048] First conversion period T1

[0049] Second converter period T2

[0050] First Dead Zone Time T10

[0051] Second Dead Zone Time T20

[0052] The first arc extinguishing period is t0~t1

[0053] The second arc extinguishing period t1~t2

[0054] The third arc extinguishing period t2~t3

[0055] First discharge path B1

[0056] Second discharge path B2

[0057] Third discharge path B3

[0058] First latching path B4

[0059] Second latch path B5

[0060] Fourth discharge path B6

[0061] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0062] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0063] Furthermore, the terms "first," "second," etc., used in this application's specification are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Additionally, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0064] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0065] Please see Figure 1 This application provides a power conversion circuit 100 for providing AC power to a load device 200. The power conversion circuit 100 includes a DC power port 10, multiple step-down chopper circuits 20, a DC-AC conversion circuit 30, a detection circuit 50, and a controller 60.

[0066] The DC power port 10 is used to receive a first DC voltage.

[0067] The DC-AC conversion circuit 30 (also called an H-bridge circuit) includes a DC input port 31, an AC output port 32, and multiple commutator switches, each of which includes a control terminal. Each buck chopper circuit 20 is electrically connected between the DC power supply port 10 and the DC input port 31 of the DC-AC conversion circuit 30. Each buck chopper circuit 20 can receive a first DC voltage provided by the DC power supply port 10 and convert the first DC voltage to a second DC voltage. Each buck chopper circuit 20 includes a chopper switch and a first inductor, the chopper switch including a control terminal. The DC input port 31 of the DC-AC conversion circuit 30 receives the second DC voltage, converts the received second DC voltage into an AC voltage, and outputs the AC voltage through the AC output port 32. The voltage conversion times of the multiple buck chopper circuits 20 are staggered.

[0068] The detection circuit 50 is electrically connected to the AC output port 32 of the DC-AC conversion circuit 30. The detection circuit 50 is used to detect the AC voltage or AC current output by the DC-AC conversion circuit 30 and output a corresponding detection signal, which is a current signal or a voltage signal.

[0069] The controller 60 is electrically connected to the detection circuit 50, the control terminals of each of the chopper switches, and the control terminals of each of the commutator switches. The controller 60 receives the detection signal output by the detection circuit 50, determines whether the power conversion circuit 100 generates an arc based on the detection signal, and, after determining that the power conversion circuit 100 generates an arc, controls each of the chopper switches and each of the commutator switches to disconnect during a first arc-extinguishing period, causing the DC-AC conversion circuit 30 and the plurality of buck chopper circuits 20 to stop power conversion, and causing each first inductor to release part of its energy to the DC power port 10, leaving some energy remaining. The controller 60 is also used to control each of the chopper switches to disconnect and control each of the commutator switches to turn on during a second arc-extinguishing period after determining that the power conversion circuit 100 generates an arc, causing each first inductor to continue flowing through the turned-on commutator switches, thereby causing each first inductor to latch the remaining energy. The start time of the second arc-extinguishing period is the end time of the first arc-extinguishing period.

[0070] It should be noted that existing H-bridge circuits receive a constant DC voltage, therefore the amplitude of the output AC voltage is also constant, and they cannot output stepped waves with different amplitudes. The power conversion circuit 100 provided in this application, by setting multiple buck chopper circuits 20 between the DC power port 10 and the DC-AC conversion circuit 30, converts the received first DC voltage into a second DC voltage and outputs it to the DC-AC conversion circuit 30. The DC-AC conversion circuit 30 then converts the second DC voltage back into AC voltage. Thus, the amplitude of the AC voltage can be adjusted by using multiple buck chopper circuits 20, thereby achieving stepped waves with different output amplitudes, suitable for different loads. Furthermore, by setting multiple buck chopper circuits 20 in parallel and controlling them to alternately perform voltage conversion, the current can be shared among the multiple buck chopper circuits 20. On the one hand, this reduces the current of each buck chopper circuit 20, which is beneficial for device selection; on the other hand, it reduces the ripple content in the AC voltage and AC current output by the DC-AC conversion circuit 30.

[0071] An electric arc is a gas discharge phenomenon, a momentary spark produced when current passes through certain insulating media (such as air). As can be seen from glow discharge curves, abnormal glow discharges produce arcing, a sharp increase in current, and a decrease in voltage, similar to a short circuit. This can lead to problems such as damage to sputtered circuits and damage to deposited films. Therefore, arc suppression is crucial for power conversion circuits.

[0072] The power conversion circuit 100 provided in this application, during the first arc extinguishing period after detecting an electric arc, controls all the chopper switches and all the commutator switches to be turned off, causing the DC-AC conversion circuit 30 and the plurality of buck chopper circuits 20 to stop power conversion, and causing each first inductor to release part of its energy to the DC power supply port, leaving a portion of its energy remaining. During the second arc extinguishing period after determining that the power conversion circuit has generated an arc, it controls all the chopper switches to be turned off and all the commutator switches to be turned on, causing each first inductor to continue flowing through the turned-on commutator switches, thereby causing each first inductor to latch the remaining energy. On the one hand, during the first arc extinguishing period, the DC-AC conversion circuit... Both circuit 30 and the multiple step-down chopper circuits 20 stop power conversion, which can disconnect the circuit in time to prevent the arc from intensifying further. In addition, each first inductor releases some energy, which can ensure that the current is below the safe current threshold and protect the components in the circuit. On the other hand, during the second arc extinguishing period, each first inductor is allowed to freewheel through the multiple commutator switches, which can lock in some energy. Therefore, when the power conversion circuit 100 restarts after the arc extinguishing, the current in each first inductor does not need to rise from zero. The load current can rise rapidly to the current when it is stable. This not only saves energy, but also makes the power conversion circuit 100 start up more smoothly and avoids secondary arcing due to restarting.

[0073] For example, the DC power port 10 is used to be electrically connected to an AC-DC conversion circuit or an energy storage element (such as a battery, supercapacitor, etc.), and the DC power port 10 is used to receive a first DC voltage provided by the AC-DC conversion circuit or the energy storage element.

[0074] In this embodiment, the power conversion circuit 100 further includes a voltage regulator capacitor C1, which is electrically connected to the DC power port 10. The voltage regulator capacitor C1 is used to stabilize the first DC voltage. When each of the first inductors releases energy to the DC power port 10, the released energy can charge the voltage regulator capacitor C1.

[0075] For example, the controller 60 can determine whether the power conversion circuit 100 has generated an electric arc by comparing the current or voltage waveforms of two consecutive cycles. Specifically, if the waveforms of two consecutive cycles differ significantly, it is determined that the power conversion circuit 100 has generated an electric arc. Of course, other methods can be used to detect electric arcs in other embodiments, which are not limited here.

[0076] Furthermore, the controller 60 is also configured to control all the chopper switches and all the commutator switches to disconnect during the third arc-extinguishing period after the power conversion circuit 100 generates an arc, and to continue controlling the plurality of buck chopper circuits 20 to convert the first DC voltage into the second DC voltage at the end of the third arc-extinguishing period, and to control the DC-AC conversion circuit 30 to convert the second DC voltage into an AC voltage with a period of a preset operating period T. The start time of the third arc-extinguishing period is the end time of the second arc-extinguishing period.

[0077] Thus, after executing the arc extinguishing control process, the controller 60 automatically controls the power conversion circuit 100 to restart and continue power conversion, achieving a high degree of automation and eliminating the need for manual operation. Furthermore, by setting a third arc extinguishing period before restarting, all chopper switches and commutator switches are disconnected, preventing short circuits in the DC-AC conversion circuit 30.

[0078] Furthermore, the DC power port 10 includes a first power terminal S+ and a second power terminal S-, and the DC input port 31 includes a first input terminal 311 and a second input terminal 312, with the first input terminal 311 and the first power terminal S+ being electrically connected.

[0079] In this embodiment, the number of the plurality of buck chopper circuits 20 is two. Each buck chopper circuit 20 includes a first diode, a first inductor, a chopper switch, and a voltage regulator capacitor C2. The voltage regulator capacitor C2 is shared by all the buck chopper circuits 20. Figure 2 As shown, the first buck chopper circuit 20 includes a first diode D11, a first inductor L11, a chopper switch M11, and the voltage regulator capacitor C2. The second buck chopper circuit 20 includes a first diode D12, a first inductor L12, a chopper switch M12, and the voltage regulator capacitor C2.

[0080] Since the two buck chopper circuits 20 have the same circuit structure and working principle, the first buck chopper circuit 20 will be described in detail below.

[0081] The first diode D11 includes an anode and a cathode, and the cathode of the first diode D11 is electrically connected to the first power supply terminal S+.

[0082] The first inductor L11 is electrically connected between the anode of the first diode D11 and the second input terminal 312 of the DC-AC conversion circuit 30.

[0083] The chopper switch M11 is electrically connected between the second power supply terminal S- and the anode of the first diode D11.

[0084] The voltage stabilizing capacitor C2 includes a first terminal and a second terminal that are electrically connected to the first input terminal 311 and the second input terminal 312 of the DC-AC conversion circuit 30 in a one-to-one correspondence.

[0085] When the first buck chopper circuit 20 performs voltage conversion, the chopper switch M11 is alternately turned on or off. When the chopper switch M11 is turned on, the turned-on chopper switch M11 and the first inductor L11 form a charging path for charging the voltage regulator capacitor C2. The first DC voltage provided by the DC power supply port 10 charges the voltage regulator capacitor C2 through the charging path, so that the voltage difference between the two ends of the voltage regulator capacitor C2 is the second DC voltage. When the chopper switch M11 is turned off, the first inductor L11 and the first diode D11 form a freewheeling path, so that the voltage difference between the two ends of the voltage regulator capacitor C2 is maintained at the second DC voltage.

[0086] The voltage value of the second DC voltage is proportional to the conduction time of the chopper switch M11 in one working cycle. Therefore, the voltage value of the second DC voltage can be adjusted by adjusting the conduction time (i.e., duty cycle) of the chopper switch M11 in one working cycle.

[0087] Furthermore, the power conversion circuit 100 also includes a second diode D2 and a third diode D3.

[0088] The second diode D2 includes an anode and a cathode. The anode of the second diode D2 is electrically connected to the second power supply terminal S-, and the cathode of the second diode D2 is electrically connected to the second terminal of the voltage regulator capacitor C2. The second diode D2 is used to enable unidirectional conduction from the second power supply terminal S- to the second terminal of the voltage regulator capacitor C2, thereby preventing the DC power supply port 10 from directly charging the voltage regulator capacitor C2.

[0089] The third diode D3 includes an anode and a cathode. The anode of the third diode D3 is electrically connected to the second terminal of the voltage stabilizing capacitor C2, and the cathode of the third diode D3 is electrically connected to the second input terminal 312. The third diode D3 is used to enable unidirectional conduction from the second terminal of the voltage stabilizing capacitor C2 to the second input terminal 312.

[0090] Furthermore, the AC output port 32 includes a first output terminal 321 and a second output terminal 322.

[0091] The plurality of commutator switches in the DC-AC conversion circuit 30 include a first commutator switch Q1, a second commutator switch Q2, a third commutator switch Q3, and a fourth commutator switch Q4.

[0092] The first commutator switch Q1 is electrically connected between the first input terminal 311 and the first output terminal 321.

[0093] The second commutator switch Q2 is electrically connected between the first input terminal 311 and the second output terminal 322.

[0094] The third commutator switch Q3 is electrically connected between the second input terminal 312 and the first output terminal 321.

[0095] The fourth commutator switch Q4 is electrically connected between the second input terminal 312 and the second output terminal 322.

[0096] When the DC-AC conversion circuit 30 performs power conversion, the first commutator switch Q1 and the fourth commutator switch Q4 form a first commutation path, and the second commutator switch Q2 and the third commutator switch Q3 form a second commutation path. The first commutation path and the second commutation path are alternately turned on, so that the DC-AC conversion circuit 30 outputs the AC voltage based on the second DC voltage.

[0097] Furthermore, when it is determined that the power conversion circuit 100 does not generate an electric arc, the controller 60 is also used to control the plurality of step-down chopper circuits 20 to convert the first DC voltage into the second DC voltage, and to control the DC-AC conversion circuit 30 to convert the second DC voltage into an AC voltage with a period of a preset working period T.

[0098] like Figure 2 As shown, each preset working cycle T includes a first commutation period T1, a first dead time period T10, a second commutation period T2, and a second dead time period T20 arranged in sequence. Specifically, the controller 60 is used to control the first commutator switch Q1 and the fourth commutator switch Q4 to be turned on during the first commutation period T1, thereby enabling the first commutation path to be open; to control the second commutator switch Q2 and the third commutator switch Q3 to be turned on during the second commutation period T2, thereby enabling the second commutation path to be open; and to control the plurality of commutator switches to be turned off during the first dead time period T10 and the second dead time period T20.

[0099] In this application, the duration of the first arc-extinguishing period is greater than or equal to the duration of the first dead time period, and greater than or equal to the duration of the second dead time period. This allows for a sufficiently long discharge time to be reserved for each of the first inductors, enabling the current in the first inductor to drop below a safe current threshold.

[0100] In one implementation, the duration of the first arc-extinguishing period is greater than or equal to the remaining duration of the operating cycle in which the moment when the power conversion circuit 100 generates an arc occurs. For example... Figure 2 As shown, the controller 60 detects an electric arc at time t0. The end time of the first arc-extinguishing period is time t1, the end time of the second arc-extinguishing period is time t2, and the end time of the third arc-extinguishing period (the time of restart after arc extinguishing) is time t3. Therefore, the first arc-extinguishing period is the time period t0 to t1, the second arc-extinguishing period is the time period t1 to t2, and the third arc-extinguishing period is the time period t2 to t3. The sum of the duration from the start time of the working cycle T containing time t0 to time t0 and the duration of the first arc-extinguishing period is exactly equal to a preset working cycle T. In other words, the duration of the first arc-extinguishing period is exactly equal to the remaining duration of the working cycle in which the moment when the power conversion circuit 100 generates an electric arc occurs.

[0101] It is easy to understand that the longer the duration of the first arc-extinguishing period, the more energy each of the first inductors releases. If the duration of the first arc-extinguishing period is set too short, the current of the first inductor may not have dropped below the safe current threshold. If the duration of the first arc-extinguishing period is set too long, the energy stored in the first inductor may be completely released. Therefore, when restarting after the arc extinguishing ends, each of the first inductors needs to be recharged so that the current of each of the first inductors rises from zero. Thus, the load current needs to go through a charging period to reach the current when it is in stable operation.

[0102] According to circuit principles, the discharge rate of the first inductor is determined by the inductance value of the first inductor, the capacitance values ​​of the voltage stabilizing capacitor C1 and the voltage stabilizing capacitor C2. Therefore, the duration of the first arc-extinguishing period can be determined based on the inductance value of the first inductor, the capacitance values ​​of the voltage stabilizing capacitor C1 and the voltage stabilizing capacitor C2. Under the condition that the current of the first inductor can be reduced to below the safe current threshold, the shorter the duration of the first arc-extinguishing period, the more beneficial it is for the first inductor to lock in energy.

[0103] Furthermore, please refer again. Figure 1 The power conversion circuit 100 also includes a load connection port 40 and several second inductors.

[0104] The load connection port 40 is used for electrical connection with the load device 200.

[0105] The plurality of second inductors are electrically connected between the load connection port 40 and the AC output port 32 of the DC-AC conversion circuit 30. During the second arc-extinguishing period t1 to t2, the plurality of second inductors can release energy to the load device 200 through the conducting plurality of commutator switches. For example Figure 1 As shown, the plurality of second inductors include L21, L22 and L23, which are used to convert the AC voltage output from the AC output port 32 of the DC-AC conversion circuit 30 into a square wave voltage and provide it to the load device 200.

[0106] For example, the first commutator switch Q1, the second commutator switch Q2, the third commutator switch Q3, the fourth commutator switch Q4, the chopper switch M11, and the chopper switch M12 are all NMOS transistors, and each NMOS transistor includes a parasitic diode flowing from the source to the drain.

[0107] Please refer to the following: Figures 2-5 , Figure 2 This is a timing diagram of the control signals output by the controller 60 when executing the arc extinguishing control process. Figure 3 This is a schematic diagram of the current flow in the power conversion circuit 100 during the first arc extinguishing period t0~t1 and the third arc extinguishing period t2~t3. Figure 4 This is a schematic diagram showing the current flow direction of the power conversion circuit 100 during the second arc extinguishing period t1 to t2. Figure 5 The following is a waveform diagram of the current in the first inductor L11 during the arc extinguishing control process of the power conversion circuit 100. Figures 2-5 The arc extinguishing control process is described in detail.

[0108] like Figure 3 As shown, during the first arc extinguishing period t0 to t1, the first commutator switch Q1, the second commutator switch Q2, the third commutator switch Q3, the fourth commutator switch Q4, the chopper switch M11, and the chopper switch M12 are all disconnected.

[0109] The second diode D2, the third diode D3, the first inductor L11, and the first diode D11 are sequentially connected to form a first discharge path B1. The first inductor L11 releases part of its energy to the voltage regulator capacitors C1 and C2 through the first discharge path B1, and retains the remaining energy. Figure 5 As shown, the first inductor L11 discharges during the first arc extinguishing period t0 to t1, and the current iL11 of the first inductor L11 decreases from i1 to i2, where i2 is lower than the safe current threshold.

[0110] The second diode D2, the third diode D3, the first inductor L12 and the first diode D12 are connected in sequence to form a second discharge path B2. The first inductor L12 releases part of the energy to the voltage regulator capacitor C1 and the voltage regulator capacitor C2 through the second discharge path B2 and the remaining energy is discharged.

[0111] The second diode D2, the third diode D3, the parasitic diode of the third commutator switch Q3, the second inductors L21 to L23, the load device 200, and the parasitic diode of the second commutator switch Q2 are connected in sequence to form a third discharge path B3. The second inductors L21 to L23 release energy to the voltage regulator capacitors C1 and C2 and the load device 200 through the third discharge path B3.

[0112] like Figure 4 As shown, during the second arc extinguishing period t1 to t2, the first converter switch Q1, the second converter switch Q2, the third converter switch Q3, and the fourth converter switch Q4 are all turned on, while the chopper switch M11 and the chopper switch M12 are all turned off.

[0113] The first diode D11, the conducting first commutator switch Q1, the conducting third commutator switch Q3, and the first inductor L11 are sequentially connected to form the first latching path B4. Since the first inductor L11 still has some energy remaining, based on the characteristic that inductor current cannot change abruptly, the first inductor L11 can freewheel through the first latching path B4. Because the impedance of the first latching path B4 is negligible, the first latching path B4 can almost completely latch the remaining energy of the first inductor L11. Figure 5 As shown, the current iL11 of the first inductor L11 hardly decreases during the second arc extinguishing period t1~t2, and is almost locked at i2.

[0114] The first diode D12, the conducting second commutation switch Q2, the conducting fourth commutation switch Q4, and the first inductor L12 are sequentially connected to form the second latching path B5. Since the first inductor L12 still has some energy remaining, and based on the characteristic that inductor current cannot change abruptly, the first inductor L12 can freewheel through the second latching path B5. Because the impedance of the second latching path B5 is negligible, it can almost completely latch the remaining energy of the first inductor L12.

[0115] The fourth commutator switch Q4, the parasitic diode of the third commutator switch Q3, the second inductor L21 to the second inductor L23, and the load device 200 are sequentially connected to form a fourth discharge path B6. The second inductor L21 to the second inductor L23 continue to release energy to the load device 200 through the fourth discharge path B6, thereby completely releasing the energy in the second inductor L21 to the second inductor L23.

[0116] Please refer to it again. Figure 3 During the third arc extinguishing period t2 to t3, the first commutator switch Q1, the second commutator switch Q2, the third commutator switch Q3, the fourth commutator switch Q4, the chopper switch M11, and the chopper switch M12 are all disconnected.

[0117] The second diode D2, the third diode D3, the first inductor L11, and the first diode D11 are sequentially connected to form a first discharge path B1. The first inductor L11 then releases part of its energy and the remaining energy to the voltage regulator capacitors C1 and C2 through the first discharge path B1. Figure 5 As shown, the first inductor L11 continues to discharge during the third arc extinguishing period t2 to t3, and the current iL11 of the first inductor L11 decreases from i3 to i4, with a very small decrease.

[0118] The second diode D2, the third diode D3, the first inductor L12 and the first diode D12 are connected in sequence to form the second discharge path B2. The first inductor L12 releases part of the energy and the remaining energy to the voltage regulator capacitor C1 and voltage regulator capacitor C2 through the second discharge path B2.

[0119] For example, the duration of the third arc-extinguishing period t2 to t3 is equal to the duration of the second dead time period T20. Since the duration of the third arc-extinguishing period t2 to t3 is relatively short, the energy in the first inductor L11 and the first inductor L12 will not be completely released. In order to lock in the energy in the first inductor L11 and the first inductor L12 as much as possible, the duration of the third arc-extinguishing period t2 to t3 can be set as short as possible.

[0120] Please refer to the following: Figure 1 and Figure 6 Based on the same inventive concept, this application also provides a control method for an energy conversion circuit, the control method being used to control the energy conversion circuit 100 described in any of the above embodiments.

[0121] The power conversion circuit 100 includes a DC power port 10, multiple step-down chopper circuits 20, a DC-AC conversion circuit 30, a detection circuit 50, and a controller 60.

[0122] The DC power port 10 is used to receive a first DC voltage.

[0123] The DC-AC conversion circuit 30 (also called an H-bridge circuit) includes a DC input port 31, an AC output port 32, and multiple commutator switches, each of which includes a control terminal. Each buck chopper circuit 20 is electrically connected between the DC power supply port 10 and the DC input port 31 of the DC-AC conversion circuit 30. Each buck chopper circuit 20 can receive a first DC voltage provided by the DC power supply port 10 and convert the first DC voltage to a second DC voltage. Each buck chopper circuit 20 includes a chopper switch and a first inductor, the chopper switch including a control terminal. The DC input port 31 of the DC-AC conversion circuit 30 receives the second DC voltage, converts the received second DC voltage into an AC voltage, and outputs the AC voltage through the AC output port 32. The voltage conversion times of the multiple buck chopper circuits 20 are staggered.

[0124] The detection circuit 50 is electrically connected to the DC-AC conversion circuit 30. The detection circuit 50 is used to detect the AC voltage or AC current output by the DC-AC conversion circuit 30 and output a corresponding detection signal, which is a current signal or a voltage signal.

[0125] The controller 60 is electrically connected to the detection circuit 50, the control terminals of each of the chopper switches, and the control terminals of each of the commutator switches. The controller 60 receives the detection signal output by the detection circuit 50, determines whether the power conversion circuit 100 generates an arc based on the detection signal, and, after determining that the power conversion circuit 100 generates an arc, controls each of the chopper switches and each of the commutator switches to disconnect during a first arc-extinguishing period, causing the DC-AC conversion circuit 30 and the plurality of buck chopper circuits 20 to stop power conversion, and causing each first inductor to release part of its energy to the DC power port 10, leaving some energy remaining. The controller 60 is also used to control each of the chopper switches to disconnect and control each of the commutator switches to turn on during a second arc-extinguishing period after determining that the power conversion circuit 100 generates an arc, causing each first inductor to continue flowing through the turned-on commutator switches, thereby causing each first inductor to latch the remaining energy. The start time of the second arc-extinguishing period is the end time of the first arc-extinguishing period.

[0126] like Figure 6 As shown, the control method for the power conversion circuit includes:

[0127] Step 61: Control the plurality of step-down chopper circuits 20 to convert the first DC voltage into the second DC voltage, and control the DC-AC conversion circuit 30 to convert the second DC voltage into an AC voltage with a period of a preset working period T, and output the AC voltage through the AC output port 32.

[0128] Step 62: Obtain the detection signal.

[0129] Step 63: Determine whether the power conversion circuit 100 generates an electric arc based on the detection signal. If it is determined that the power conversion circuit 100 does not generate an electric arc, then continue to execute step 61, continue to control the plurality of step-down chopper circuits 20 to convert the first DC voltage into the second DC voltage, and control the DC-AC conversion circuit 30 to convert the second DC voltage into an AC voltage with a period of a preset working period T, and output the AC voltage through the AC output port 32. If it is determined that the power conversion circuit 100 has generated an electric arc, then execute step 64.

[0130] Step 64: Execute the arc extinguishing control process.

[0131] Please see Figure 7 In one embodiment, step 64 includes steps 641 to 642, as follows:

[0132] Step 641: During the first arc extinguishing period after the power conversion circuit 100 generates an arc, control each of the chopper switches and each of the commutator switches to disconnect, so that the DC-AC conversion circuit 30 and the plurality of buck chopper circuits 20 stop power conversion, and each of the first inductors releases part of its energy to the DC power supply port 10 and retains the remaining energy.

[0133] Step 642: During the second arc extinguishing period after the power conversion circuit 100 generates an arc, control all the chopper switches to be turned off and control all the commutator switches to be turned on, so that each first inductor can continue current through the multiple commutator switches that are turned on, thereby enabling each first inductor to latch the remaining energy.

[0134] The start time of the second arc extinguishing period is the end time of the first arc extinguishing period.

[0135] Please see Figure 8 In another embodiment, step 64 includes steps 641 to 643, as follows:

[0136] Step 641: During the first arc extinguishing period after the power conversion circuit 100 generates an arc, control each of the chopper switches and each of the commutator switches to disconnect, so that the DC-AC conversion circuit 30 and the plurality of buck chopper circuits 20 stop power conversion, and each of the first inductors releases part of its energy to the DC power supply port 10 and retains the remaining energy.

[0137] Step 642: During the second arc extinguishing period after the power conversion circuit 100 generates an arc, control all the chopper switches to be turned off and control all the commutator switches to be turned on, so that each first inductor can continue current through the multiple commutator switches that are turned on, thereby enabling each first inductor to latch the remaining energy.

[0138] Step 643: During the third arc-extinguishing period after the power conversion circuit 100 generates an arc, control all the chopper switches and all the commutator switches to disconnect. At the end of the third arc-extinguishing period, step 61 is executed again.

[0139] The start time of the third arc extinguishing period is the end time of the second arc extinguishing period.

[0140] Based on the same inventive concept, this application also provides a computer-readable storage medium storing executable instructions, which, when executed by a processor, implement the control method of the power conversion circuit described above.

[0141] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0142] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0143] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0144] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0145] Memory may include non-persistent memory in computer-readable storage media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of a computer-readable storage medium.

[0146] Computer-readable storage media include both permanent and non-permanent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable storage media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0147] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. An electrical energy conversion circuit, characterized in that, The power conversion circuit includes: A DC power supply port is used to receive a first DC voltage. A DC-AC converter circuit and multiple buck chopper circuits are provided. The DC-AC converter circuit includes a DC input port, an AC output port, and multiple commutator switches, each of which includes a control terminal. Each buck chopper circuit is electrically connected between the DC power supply port and the DC input port of the DC-AC converter circuit. Each buck chopper circuit can receive a first DC voltage provided by the DC power supply port and convert the first DC voltage to a second DC voltage. Each buck chopper circuit includes a chopper switch and a first inductor, the chopper switch including a control terminal. The DC input port of the DC-AC converter circuit receives the second DC voltage, and the DC-AC converter circuit can convert the received second DC voltage into an AC voltage and output the AC voltage through the AC output port. The voltage conversion times of the multiple buck chopper circuits are staggered. A detection circuit, electrically connected to the AC output port of the DC-AC conversion circuit, is used to detect the AC voltage or AC current output by the DC-AC conversion circuit and output a corresponding detection signal, wherein the detection signal is a current signal or a voltage signal; and The controller is electrically connected to the detection circuit, the control terminals of each of the chopper switches, and the control terminals of each of the commutator switches. The controller receives the detection signal output by the detection circuit, determines whether an arc is generated in the power conversion circuit based on the detection signal, and, during a first arc-extinguishing period after determining that an arc has been generated in the power conversion circuit, controls each of the chopper switches and each of the commutator switches to disconnect, causing the DC-AC conversion circuit and the plurality of buck chopper circuits to stop power conversion, and causing each of the first inductors to release a portion of energy to the DC power supply port while retaining a portion of the energy. The controller is also used during a second arc-extinguishing period after determining that an arc has been generated in the power conversion circuit, to control each of the chopper switches to disconnect and control each of the commutator switches to turn on, causing each of the first inductors to continue flowing through the turned-on commutator switches, thereby causing each of the first inductors to latch the remaining energy. The start time of the second arc-extinguishing period is the end time of the first arc-extinguishing period.

2. The power conversion circuit as described in claim 1, characterized in that, The controller is further configured to control all the chopper switches and all the commutator switches to disconnect during the third arc extinguishing period after the power conversion circuit generates an arc, and to continue controlling the plurality of buck chopper circuits to convert the first DC voltage into the second DC voltage at the end of the third arc extinguishing period, and to control the DC-AC conversion circuit to convert the second DC voltage into an AC voltage with a period of a preset working cycle; wherein the start time of the third arc extinguishing period is the end time of the second arc extinguishing period.

3. The power conversion circuit as described in claim 1 or 2, characterized in that, The DC power port includes a first power terminal and a second power terminal, and the DC input port includes a first input terminal and a second input terminal, wherein the first input terminal and the first power terminal are electrically connected. Each of the buck chopper circuits includes: The first diode includes an anode and a cathode, and the cathode of the first diode is electrically connected to the first power supply terminal. The first inductor is electrically connected between the anode of the first diode and the second input terminal; The chopper switch is electrically connected between the second power supply terminal and the anode of the first diode; and A voltage regulator capacitor shared by all buck chopper circuits, the voltage regulator capacitor includes a first end and a second end that are electrically connected to the first input terminal and the second input terminal respectively; The chopper switch is alternately turned on and off. When the chopper switch is turned on, the turned-on chopper switch and the first inductor form a charging path for charging the voltage regulator capacitor. The first DC voltage provided by the DC power supply port charges the voltage regulator capacitor through the charging path, so that the voltage difference between the two ends of the voltage regulator capacitor is the second DC voltage. When the chopper switch is turned off, the first inductor and the first diode form a freewheeling path, so that the voltage difference between the two ends of the voltage regulator capacitor is maintained at the second DC voltage.

4. The power conversion circuit as described in claim 3, characterized in that, The power conversion circuit also includes: A second diode includes an anode and a cathode. The anode of the second diode is electrically connected to the second power supply terminal, and the cathode of the second diode is electrically connected to the second terminal of the voltage-stabilizing capacitor. The second diode is used to enable unidirectional conduction from the second power supply terminal to the second terminal of the voltage-stabilizing capacitor. The third diode includes an anode and a cathode. The anode of the third diode is electrically connected to the second terminal of the voltage-stabilizing capacitor, and the cathode of the third diode is electrically connected to the second input terminal. The third diode is used to enable unidirectional conduction from the second terminal of the voltage-stabilizing capacitor to the second input terminal.

5. The power conversion circuit as described in claim 4, characterized in that, The AC output port includes a first output terminal and a second output terminal; The plurality of commutator switches in the DC-AC conversion circuit include: The first commutator switch is electrically connected between the first input terminal and the first output terminal; The second commutator switch is electrically connected between the first input terminal and the second output terminal; The third commutator switch is electrically connected between the second input terminal and the first output terminal; and The fourth commutator switch is electrically connected between the second input terminal and the second output terminal; The first commutator switch and the fourth commutator switch form a first commutator path, and the second commutator switch and the third commutator switch form a second commutator path. The first commutator path and the second commutator path are alternately turned on, so that the DC-AC conversion circuit outputs the AC voltage based on the second DC voltage.

6. The power conversion circuit as described in claim 5, characterized in that, When it is determined that no electric arc is generated in the power conversion circuit, the controller is further configured to control the plurality of buck chopper circuits to convert the first DC voltage into the second DC voltage, and to control the DC-AC conversion circuit to convert the second DC voltage into an AC voltage with a period of a preset working cycle; wherein, each preset working cycle includes a first commutation period, a first dead period, a second commutation period, and a second dead period arranged in sequence; specifically, the controller is configured to control the first commutation switch and the fourth commutation switch to be turned on during the first commutation period, thereby enabling the first commutation path to be turned on; control the second commutation switch and the third commutation switch to be turned on during the second commutation period, thereby enabling the second commutation path to be turned on; and control the plurality of commutation switches to be turned off during the first dead period and the second dead period. The duration of the first arc extinguishing period is greater than or equal to the duration of the first dead zone period, and is greater than or equal to the duration of the second dead zone period.

7. The power conversion circuit as described in claim 1, characterized in that, The power conversion circuit also includes: A load connection port is used for electrical connection to a load device; and Several second inductors are electrically connected between the load connection port and the AC output port of the DC-AC conversion circuit; during the second arc extinguishing period after the controller determines that the power conversion circuit has generated an arc, the several second inductors can release energy to the load device through the multiple commutator switches that are turned on.

8. A control method for an electrical energy conversion circuit, characterized in that, The power conversion circuit includes: A DC power supply port is used to receive a first DC voltage. A DC-AC converter circuit and multiple buck chopper circuits are provided. The DC-AC converter circuit includes a DC input port, an AC output port, and multiple commutator switches, each of which includes a control terminal. Each buck chopper circuit is electrically connected between the DC power supply port and the DC input port of the DC-AC converter circuit. Each buck chopper circuit can receive a first DC voltage provided by the DC power supply port and convert the first DC voltage to a second DC voltage. Each buck chopper circuit includes a chopper switch and a first inductor, the chopper switch including a control terminal. The DC input port of the DC-AC converter circuit receives the second DC voltage, and the DC-AC converter circuit can convert the received second DC voltage into an AC voltage and output the AC voltage through the AC output port. The voltage conversion times of the multiple buck chopper circuits are staggered. The detection circuit is electrically connected to the DC-AC conversion circuit. The detection circuit is used to detect the AC voltage or AC current output by the DC-AC conversion circuit and output a corresponding detection signal, which is a current signal or a voltage signal. The control method for the power conversion circuit includes: The system controls the plurality of step-down chopper circuits to convert the first DC voltage into the second DC voltage, and controls the DC-AC conversion circuit to convert the second DC voltage into an AC voltage with a period of a preset working cycle, and outputs the AC voltage through the AC output port. Acquire the detection signal; Based on the detection signal, it is determined whether the power conversion circuit generates an electric arc; If it is determined that no electric arc is generated in the power conversion circuit, then the plurality of step-down chopper circuits are controlled to convert the first DC voltage into the second DC voltage, and the DC-AC conversion circuit is controlled to convert the second DC voltage into an AC voltage with a period of a preset working cycle, and the AC voltage is output through the AC output port; and If it is determined that an electric arc has been generated in the power conversion circuit, then the arc extinguishing control process is executed; The arc extinguishing control process includes: During the first arc-extinguishing period after the power conversion circuit generates an arc, all the chopper switches and all the commutator switches are turned off, causing the DC-AC conversion circuit and the plurality of buck chopper circuits to stop power conversion, and causing each of the first inductors to release part of its energy to the DC power supply port, with the remaining energy; and During the second arc-extinguishing period after the power conversion circuit generates an arc, all the chopper switches are turned off and all the commutator switches are turned on, so that each first inductor continues to flow through the multiple turned-on commutator switches, thereby allowing each first inductor to latch the remaining energy; wherein, the start time of the second arc-extinguishing period is the end time of the first arc-extinguishing period.

9. The control method for the power conversion circuit as described in claim 8, characterized in that, The control method for the power conversion circuit also includes: During the third arc-extinguishing period after the generation of an electric arc in the power conversion circuit, all the chopper switches and all the commutator switches are controlled to disconnect; and At the end of the third arc extinguishing period, the plurality of step-down chopper circuits are controlled to convert the first DC voltage into the second DC voltage, and the DC-AC conversion circuit is controlled to convert the second DC voltage into an AC voltage with a period of a preset working cycle; wherein, the start time of the third arc extinguishing period is the end time of the second arc extinguishing period.

10. A computer-readable storage medium, characterized in that, The device stores executable instructions, which, when executed by a processor, implement the control method for the power conversion circuit as described in claim 8 or 9.

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