Control method of single-stage AC / DC conversion circuit, controller and power supply module

Abstract

The invention provides a control method of a single-stage AC / DC conversion circuit, a controller and a power supply module. The single-stage AC-DC conversion circuit comprises a primary side bridge arm switching circuit, an isolation circuit and a secondary side bridge arm switching circuit. The method comprises the following steps: acquiring an alternating current side voltage, and determining a maximum phase voltage and a minimum phase voltage based on the alternating current side voltage; and in response to a shutdown instruction, controlling the primary side bridge arm circuit corresponding to the maximum phase voltage and the primary side bridge arm circuit corresponding to the minimum phase voltage to act, so that an electrical loop is formed between the midpoints of the two bridge arms and the primary side of the isolation circuit, and the direction of the inductive current and the direction of the inductive voltage on the primary side of the isolation circuit in the electrical loop are opposite. The invention aims to realize safe shutdown of the primary side bridge arm switching circuit in the single-stage AC / DC conversion circuit and improve the safety and stability of the shutdown execution process of the single-stage AC / DC conversion circuit.

Description

Technical Field

[0001] The present application relates to the technical field of single-stage AC-DC conversion circuit control, and particularly relates to a control method, a controller, and a power supply module for a single-stage AC-DC conversion circuit. Background Art

[0002] Compared with the traditional two-stage structure, the single-stage AC-DC conversion circuit omits the intermediate bus capacitor and has advantages such as high power density, high efficiency, and long service life. However, in the case of needing to stop, for example, when the current operation ends and needs to stop to complete shutdown, if all the switching tubes on the primary side bridge arm switching circuit are directly turned off, there may be a situation of overvoltage of the switching tubes caused by the interruption of the inductor current on the primary side of the isolation circuit, which affects the safety and reliability of the single-stage AC-DC conversion circuit during the shutdown process, and further affects the overall safety and stability of the single-stage AC-DC conversion circuit. Summary of the Invention

[0003] To achieve the above object, the present application proposes a control method, a controller, and a power supply module for a single-stage AC-DC conversion circuit, aiming to achieve safe shutdown of the primary side bridge arm switching circuit in the single-stage AC-DC conversion circuit and improve the safety and stability of the single-stage AC-DC conversion circuit during the shutdown process.

[0004] The present application proposes a control method for a single-stage AC-DC conversion circuit. The single-stage AC-DC conversion circuit includes a primary side bridge arm switching circuit, an isolation circuit, and a secondary side bridge arm switching circuit. The primary side bridge arm switching circuit includes three primary side bridge arm circuits. The midpoints of the three primary side bridge arm circuits are used to be electrically connected to the AC side. The first ends of the three primary side bridge arm circuits are respectively connected to the first end of the primary side of the isolation circuit, and the second ends of the three primary side bridge arm circuits are respectively connected to the second end of the primary side of the isolation circuit. It is characterized in that the control method of the single-stage AC-DC conversion circuit includes:

[0005] Obtain the AC side voltage;

[0006] In response to a shutdown instruction, based on the AC side voltage, control the primary side bridge arm circuit corresponding to the maximum phase voltage and the primary side bridge arm circuit corresponding to the minimum phase voltage to act, so that an electrical loop is formed between the midpoints of the two bridge arms and the primary side of the isolation circuit, and in the electrical loop, the direction of the inductor current on the primary side of the isolation circuit is opposite to the direction of the inductor voltage.

[0007] Optionally, the obtaining of the AC side voltage includes:

[0008] Obtain the working mode and determine the AC side voltage based on the working mode;

[0009] Wherein, the working modes include a rectification mode, a V2G inversion mode, and a V2L inversion mode;

[0010] When the working mode is the rectification mode and the V2G inversion mode, the AC side voltage includes the AC voltage of the AC power source connected to the AC side;

[0011] When the working mode is the V2L inversion mode, the AC side voltage includes the AC voltage output from the primary side bridge arm switching circuit to the AC side.

[0012] Optionally, controlling the operation of the primary side bridge arm circuit corresponding to the maximum phase voltage and the primary side bridge arm circuit corresponding to the minimum phase voltage based on the AC side voltage includes:

[0013] Based on the AC side voltage, determining the sector position of the AC side voltage in a preset AC voltage sector;

[0014] Based on the sector position, controlling the operation of the primary side bridge arm circuit corresponding to the maximum phase voltage and the primary side bridge arm circuit corresponding to the minimum phase voltage; wherein, the preset AC voltage sector includes a three-phase AC line voltage sector or a three-phase AC phase voltage sector.

[0015] Optionally, forming an electrical loop between the midpoints of the two bridge arms and the primary side of the isolation circuit includes;

[0016] When the inductor current on the primary side of the isolation circuit is a positive current, an electrical loop is formed between the midpoint of the primary side bridge arm circuit corresponding to the minimum phase voltage, the upper bridge arm circuit of the primary side bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the lower bridge arm circuit of the primary side bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage;

[0017] When the current on the primary side of the isolation circuit is a negative current, an electrical loop is formed between the midpoint of the primary side bridge arm circuit corresponding to the minimum phase voltage, the lower bridge arm circuit of the primary side bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the upper bridge arm circuit of the primary side bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage.

[0018] Optionally, the primary side bridge arm circuit includes two bidirectional switch units electrically connected to each other, the bridge arm midpoint includes the connection point of the two bidirectional switch units, and the bidirectional switch unit includes an upper switch tube and a lower switch tube;

[0019] The diode modules in the upper switching tubes are arranged with their anodes facing each other with respect to the diode modules in the lower switching tubes. The operations of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage include:

[0020] Controlling the upper switching tube in the upper bridge arm circuit and the lower switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state, and controlling the lower switching tube in the upper bridge arm circuit and the upper switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in the conducting state;

[0021] Controlling the lower switching tube in the upper bridge arm circuit and the upper switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the non-conducting state, and controlling the upper switching tube in the upper bridge arm circuit and the lower switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in the non-conducting state;

[0022] Or,

[0023] The diode modules in the upper switching tubes are arranged with their cathodes facing each other with respect to the diode modules in the lower switching tubes. The operations of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage include:

[0024] Controlling the upper switching tube in the upper bridge arm circuit and the lower switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in the conducting state, and controlling the lower switching tube in the upper bridge arm circuit and the upper switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state;

[0025] Controlling the lower switching tube in the upper bridge arm circuit and the upper switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in the non-conducting state, and controlling the upper switching tube in the upper bridge arm circuit and the lower switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the non-conducting state.

[0026] Optionally, the operations of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to form an electrical loop between the midpoints of the bridge arms and the primary side of the isolation circuit include:

[0027] Obtaining the inductor current on the primary side of the isolation circuit;

[0028] When the inductor current is a positive current, control the upper arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage and the lower arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state, so as to form the electrical loop between the midpoint of the bridge arm of the primary bridge arm circuit corresponding to the minimum phase voltage, the upper arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the lower arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage;

[0029] When the inductor current is a negative current, control the lower arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage and the upper arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state, so as to form the electrical loop between the midpoint of the bridge arm of the primary bridge arm circuit corresponding to the minimum phase voltage, the lower arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the upper arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage.

[0030] Optionally, after controlling the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to act, so as to form an electrical loop between the midpoints of their bridge arms and the primary side of the isolation circuit and the directions of the inductor current and the inductor voltage on the primary side of the isolation circuit in the electrical loop are opposite, the method further includes:

[0031] After a preset first time period, control the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to be in the stopped working state; or,

[0032] After the step of controlling the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to act in response to the shutdown instruction, so as to form an electrical loop between the midpoints of their bridge arms and the primary side of the isolation circuit, the method further includes:

[0033] Obtain the inductor current on the primary side of the isolation circuit;

[0034] When the inductor current is less than a preset first current threshold, control the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to be in the stopped working state.

[0035] The present application also provides a controller, which includes: a memory, a processor, and a control program for a single-stage AC-DC conversion circuit stored on the memory and executable on the processor. The control program for the single-stage AC-DC conversion circuit is configured to implement the control method for the single-stage AC-DC conversion circuit as described in any one of the above.

[0036] The present application provides a power module, including the control method for the single-stage AC-DC conversion circuit as described in any one of the above; and / or, the controller as described above.

[0037] The control method for the single-stage AC-DC conversion circuit of the present application includes: obtaining the AC-side voltage; in response to a shutdown instruction, based on the AC-side voltage, controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage, so that an electrical loop is formed between the midpoints of the two bridge arms and the primary side of the isolation circuit, and in the electrical loop, the direction of the inductor current on the primary side of the isolation circuit is opposite to the direction of the inductor voltage. Through the above settings, when the single-stage AC-DC conversion circuit needs to shut down, the controller can control the above-mentioned primary bridge arm circuit to operate to form a corresponding electrical loop, and make the direction of the inductor current transmitted in the electrical loop opposite to the direction of the inductor voltage applied across the inductor, so that the inductor current gradually decreases until it reaches zero. In this way, when the inductor current drops below a certain value, the controller can control all the switching tubes in the primary bridge arm switching circuit to be in a non-conducting state, so as to achieve the safe shutdown of the primary bridge arm switching circuit in the single-stage AC-DC conversion circuit, thereby improving the safety and stability of the single-stage AC-DC conversion circuit during the shutdown process. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0039] Figure 1 It is a schematic flowchart of an embodiment of the control method for the single-stage AC-DC conversion circuit of the present application;

[0040] Figure 2 It is a schematic flowchart of another embodiment of the control method for the single-stage AC-DC conversion circuit of the present application;

[0041] Figure 3 It is a schematic flowchart of yet another embodiment of the control method for the single-stage AC-DC conversion circuit of the present application;

[0042] Figure 4 It is a schematic flowchart of still another embodiment of the control method for the single-stage AC-DC conversion circuit of the present application;

[0043] Figure 5 It is a schematic diagram of the circuit topology of the single-stage AC-DC conversion circuit in the prior art;

[0044] Figure 6 It is a schematic diagram of the sectors of the three-phase AC phase voltage;

[0045] Figure 7 It is a schematic diagram of the inductor current flow direction when the maximum phase voltage is Ua, the minimum phase voltage is Uc, and the inductor current is positive in an embodiment of the single-stage AC-DC conversion circuit of the present application;

[0046] Figure 8 For corresponding Figure 7 Schematic diagrams of the primary side voltage waveform, primary side current waveform, and secondary side voltage waveform;

[0047] Figure 9 It is a schematic diagram of the inductor current flow direction when the maximum phase voltage is Ua, the minimum phase voltage is Uc, and the inductor current is negative in an embodiment of the single-stage AC-DC conversion circuit of the present application;

[0048] Figure 10 For corresponding Figure 9 Schematic diagrams of the primary side voltage waveform, primary side current waveform, and secondary side voltage waveform;

[0049] Figure 11 It is a schematic diagram of the driving signal waveforms output to each switch tube in the primary side bridge arm switch circuit when the maximum phase voltage is Ua and the minimum phase voltage is Uc in an embodiment of the single-stage AC-DC conversion circuit of the present application;

[0050] Figure 12 In an embodiment of the control method for the single-stage AC-DC conversion circuit of the present application, when stopping in different sectors, for Figure 5 Schematic table of the driving signals sent to each switch tube in the primary side bridge arm switch circuit shown;

[0051] The realization, functional features, and advantages of the purpose of the present application will be further described with reference to the embodiments and the accompanying drawings. Specific Embodiments

[0052] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without making creative efforts belong to the scope of protection of the present application.

[0053] It should be noted that if there are directional indications (such as up, down, left, right, front, back, etc.) involved in the embodiments of the present application, the directional indications are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0054] In addition, if there are descriptions such as "first", "second", etc. involved in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0055] The single-stage AC-DC conversion circuit omits the intermediate bus capacitor compared with the traditional two-stage structure, and has advantages such as high power density, high efficiency, and long life. However, when it needs to stop, for example, when the current work is over and it needs to stop to complete shutdown, if all the switching tubes on the primary side bridge arm switching circuit are directly turned off, there may be a situation where the switching tubes are overvoltage due to the interruption of the inductor current on the primary side of the isolation circuit, which affects the safety and reliability of the single-stage AC-DC conversion circuit during the shutdown process, and further affects the overall safety and stability of the single-stage AC-DC conversion circuit.

[0056] It should be understood that referring to Figure 5 , in the prior art, when the single-stage AC-DC conversion circuit needs to stop due to shutdown requirements or fault reasons, since there is no capacitor connected in parallel at both ends of the primary side on the primary side, the shutdown strategy for the secondary side bridge arm switching circuit is not applicable to the primary side bridge arm switching circuit. However, if all the switching tubes in the primary side bridge arm switching circuit are directly switched to the non-conducting state, the inductor current on the primary side of the isolation circuit will cause the voltage stress of the switching tubes on the primary side bridge arm circuit in the primary side bridge arm switching circuit to be too large, and it is easy to damage the switching tubes.

[0057] For this reason, the present application proposes a control method for a single-stage AC-DC conversion circuit. The single-stage AC-DC conversion circuit includes a primary side bridge arm switching circuit, an isolation circuit, and a secondary side bridge arm switching circuit. The primary side bridge arm switching circuit includes three primary side bridge arm circuits. The bridge arm midpoints of the three primary side bridge arm circuits are used to be electrically connected to the AC side. The first ends of the three primary side bridge arm circuits are respectively connected to the first end of the primary side of the isolation circuit, and the second ends of the three primary side bridge arm circuits are respectively connected to the second end of the primary side of the isolation circuit.

[0058] Among them, the above control method can be stored and executed by using the memory in the controller. The controller can be implemented by, for example, MCU, DSP (Digital Signal Process), FPGA (Field Programmable Gate Array), PLC, SOC (System On Chip), etc. The single-stage AC-DC conversion circuit can be integrated with the controller in the same device, such as an on-vehicle charger, a single-stage AC-DC conversion circuit module, a charging pile, a power supply device, etc., or can be independently set and electrically connected to the device provided with the single-stage AC-DC conversion circuit to realize the control of the single-stage AC-DC conversion circuit. Refer to Figure 5 The following shows a circuit topology schematic diagram of a single-stage AC-DC conversion circuit in the prior art. Among them, the primary side bridge arm switch circuit includes three primary side bridge arm circuits. The midpoints of the three primary side bridge arm circuits are respectively electrically connected to the AC side through filter circuits, such as electrically connected to the AC power grid on the AC side, for accessing three-phase AC voltage ( Figure 5 Ua, Ub, and Uc shown in are only used to represent the AC voltages of different phases accessed). The primary side of the isolation circuit consists of the primary side of the transformer, a capacitor, and an inductor. The two ends of the primary side of the isolation circuit are respectively electrically connected to the two ends of the three primary side bridge arm circuits. The voltage across the inductor is the inductor voltage, and the current flowing through the inductor is the inductor current (primary side current). In an example, refer to Figure 5 As shown, the primary side bridge arm circuit can be composed of two bidirectional switch units. The two bidirectional switch units include two switch tubes arranged opposite to each other. The primary side bridge arm switch circuit under this topology can, under the control of the controller, realize the frequency conversion processing of the AC voltage accessed on the AC side and output it to the primary side of the isolation circuit, or perform frequency conversion processing on the AC voltage coming from the primary side and then output it, that is, it has the ability of bidirectional frequency conversion. The secondary side bridge arm switch circuit is implemented by using a full-bridge switch circuit. The secondary side bridge arm switch circuit can, under the control of the controller, realize bidirectional AC-DC conversion, or realize single-phase rectification and single-phase inversion.

[0059] Refer to Figure 1 , in an embodiment of the present application, the control method of the single-stage AC-DC conversion circuit includes:

[0060] Step S100: Obtain the AC side voltage;

[0061] In this embodiment, the AC-side voltage of the single-stage AC-DC conversion circuit can be the voltage output to the AC side, such as the AC voltage when output to an AC device; or the voltage on the AC side, such as the voltage on the power grid when connected to the power grid. A voltage detection circuit can be provided in the single-stage AC-DC conversion circuit or in a device provided with the single-stage AC-DC conversion circuit to detect the voltage on the AC side of the single-stage AC-DC conversion circuit. Among them, the voltage detection circuit can be implemented by using a voltage detection chip or a resistor voltage division circuit.

[0062] In addition, it should be understood that from the above content, the AC-side voltage can be the voltage on the AC side or the voltage output by the single-stage AC-DC conversion circuit to the AC side. Therefore, in one embodiment, for the single-stage AC-DC conversion circuit with the ability of bidirectional inversion / rectification, the controller can determine the corresponding AC-side voltage based on the current working mode. Among them, the obtaining of the AC-side voltage includes: obtaining the working mode and determining the AC-side voltage based on the working mode; among them, the working mode includes a rectification mode, a V2G inversion mode, and a V2L inversion mode. In the rectification mode, the AC voltage of the AC power supply connected to the AC side of the single-stage AC-DC conversion circuit will be processed by the primary side bridge arm switch circuit, the isolation circuit, and the secondary side bridge arm switch circuit and then converted into a corresponding DC voltage and output to the DC side. Among them, the AC power supply includes: an AC power supply device, a power grid, etc. In this mode, the AC-side voltage includes the AC voltage of the AC power supply connected to the AC side. For example, the AC voltage on the connected power grid. In the V2G inversion mode, the single-stage AC-DC conversion circuit will process the DC voltage connected to the DC side through the secondary side bridge arm switch circuit, the isolation circuit, and the primary side bridge arm switch circuit and then convert it into a corresponding AC voltage and output it to the AC power supply on the AC side. For example, when the current AC power supply is a 220V 50Hz power grid, the single-stage AC-DC conversion circuit can convert the DC voltage connected to the DC side and output an AC voltage of 220V / 50Hz to the power grid in the V2G inversion mode. In this mode, the AC-side voltage includes the AC voltage of the AC power supply connected to the AC side. For example, the AC voltage on the connected power grid. In the V2L inversion mode, an AC electrical device is connected to the AC side of the single-stage AC-DC conversion circuit. The single-stage AC-DC conversion circuit will process the DC voltage connected to the DC side through the secondary side bridge arm switch circuit, the isolation circuit, and the primary side bridge arm switch circuit and then convert it into a corresponding AC voltage and output it to the AC electrical device to provide electrical energy for the AC electrical device. In this mode, the AC-side voltage includes the AC voltage output from the primary side bridge arm switch circuit to the AC side. This AC voltage is a preset AC voltage information, and the controller will execute the following control process according to this preset AC voltage information. For example, when the controller judges the sector position of the three-phase AC line voltage in the following embodiment, the AC voltage information includes a preset three-phase AC line voltage sector diagram.

[0063] Step S200: In response to a shutdown instruction, based on the AC-side voltage, control the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to act, so that an electrical loop is formed between the midpoints of the two bridge arms and the primary side of the isolation circuit, and in the electrical loop, the direction of the inductor current on the primary side of the isolation circuit is opposite to the direction of the inductor voltage.

[0064] In this embodiment, optionally, the shutdown instruction may be output from other circuit modules in a device provided with a single-stage AC-DC conversion circuit to the controller. For example, after the trigger module is triggered by the user as required, it outputs a shutdown instruction, or the communication module receives a shutdown instruction sent by other devices / other external terminals. Optionally, the shutdown instruction may also be given by the AC-side device to which the current device provided with the single-stage AC-DC conversion circuit is connected. For example, for a vehicle-mounted charger with a current single-stage AC-DC conversion circuit, the connected AC-side device is a charging pile. Optionally, the shutdown instruction may also be generated by the controller. For example, based on the detection of the working state of the single-stage AC-DC conversion circuit, the controller determines that the single-stage AC-DC conversion circuit is in a fault state, or receives a fault signal sent by an external device, then the controller will also generate a shutdown instruction by itself to perform a shutdown operation.

[0065] Optionally, in an embodiment, the controller may, based on the AC-side voltage obtained in the above embodiment, determine the maximum phase voltage and the minimum phase voltage among them by comparison, and then control the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage. For example, when the current single-stage AC-DC conversion circuit is operating in the rectification mode and needs to be shut down, refer to Figure 5 , Figure 5 wherein the midpoints abc of the bridge arms in the single-stage AC-DC conversion circuit are respectively connected to the three-phase voltages Ua\Ub\Uc output by the AC-side power supply through filter circuits. When the controller determines that the maximum phase voltage is Ua and the minimum phase voltage is Uc, it will control the two primary bridge arm circuits where the midpoint a of the bridge arm and the midpoint c of the bridge arm are located to operate.

[0066] It should be understood that during the normal operation of the single-stage AC-DC conversion circuit, the control unit for controlling the operation of the single-stage AC-DC conversion circuit will control the operation of the primary bridge arm switch circuit and the secondary bridge arm switch circuit according to the sector position of the current AC-side voltage in the preset AC voltage sector. Among them, the preset AC voltage sector includes a three-phase AC line voltage sector or a three-phase AC phase voltage sector. Therefore, optionally, refer to Figure 2 , in another embodiment, the controlling the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to act based on the AC-side voltage includes:

[0067] Step S210: Determine the sector position where the AC-side voltage is located in a preset AC voltage sector based on the AC-side voltage;

[0068] Step S220: Control the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage based on the sector position; wherein, the preset AC voltage sector includes a three-phase AC line voltage sector or a three-phase AC phase voltage sector.

[0069] In this embodiment, the preset AC sector can also be different firing sectors obtained from the AC-side voltage or current state. The controller can determine the AC line voltage or the AC phase voltage based on the AC-side voltage and substitute it into the preset AC sector to determine the sector position; or, the controller can also directly use the sector position determined based on the AC-side voltage at the moment before shutdown (i.e., the normal operation of the single-stage AC-DC conversion circuit) and directly use it as the sector position during shutdown execution, thereby reducing the process of detecting the current AC phase voltage and calculating the maximum and minimum phase voltages, and effectively improving the response speed. After the controller determines the sector position, it can directly issue corresponding drive signals to all the switching tubes in the primary bridge arm switch circuit based on the sector position. For example, referring to Figure 5 、 Figure 6 and Figure 12 , the R & D personnel pre-store the mapping table shown in Figure 12 in the controller. The controller can directly output corresponding drive signals to all the switching tubes based on the obtained sector position and the mapping table, so as to control the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage, thereby skipping the process of judging and confirming the primary bridge arm circuits corresponding to the maximum and minimum phase voltages in the above embodiment and improving the response speed of executing shutdown.

[0070] In one embodiment, an electrical loop is formed between the midpoints of the two bridge arms and the primary side of the isolation circuit, including;

[0071] When the inductor current on the primary side of the isolation circuit is a positive current, an electrical loop is formed among the midpoint of the primary bridge arm circuit corresponding to the minimum phase voltage, the upper bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage;

[0072] When the current on the primary side of the isolation circuit is a negative current, an electrical loop is formed among the midpoint of the bridge arm of the primary-side bridge arm circuit corresponding to the minimum phase voltage, the lower bridge arm circuit of the primary-side bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the upper bridge arm circuit of the primary-side bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage.

[0073] In this embodiment, when the inductor current is a positive current, for example, referring to Figure 5 , the inductor current flows from the positive terminal of the inductor to the negative terminal, which is a positive current. At this time, the controller will control the operation of the primary-side bridge arm circuits corresponding to the maximum phase voltage and the minimum phase voltage to form the electrical loop among the midpoint of the bridge arm of the primary-side bridge arm circuit corresponding to the minimum phase voltage, the upper bridge arm circuit of the primary-side bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the lower bridge arm circuit of the primary-side bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage. It can be understood that the above electrical loop also includes units connected to the AC side, such as the power grid, AC equipment, AC power supply, etc. Referring to Figure 7 and Figure 8 , taking the relationship of the current three-phase AC voltage as Ua>Ub>Uc, that is, the sector position is the first sector position and the second sector position as an example for explanation. The controller will control the operation of the primary-side bridge arm circuit corresponding to Ua and the primary-side bridge arm circuit corresponding to Uc, so that the inductor current, which is a positive current, will be transmitted in the electrical loop formed by the midpoint and the lower bridge arm circuit of the primary-side bridge arm circuit corresponding to Ua, the primary side of the isolation circuit, and the midpoint and the upper bridge arm circuit of the primary-side bridge arm circuit corresponding to Uc. At this time, the voltage across the inductor is uca - n·uBAT < 0, that is, a negative voltage. Since the direction of the inductor voltage applied across the inductor is opposite to the direction of the inductor current, based on the principle of volt-second balance, the inductor current will gradually decrease until it reaches zero. Similarly, when the inductor current is a negative current, for example, referring to Figure 5 , the inductor current flows from the negative terminal of the inductor to the positive terminal, which is a negative current. At this time, the controller will control the operation of the primary-side bridge arm circuits corresponding to the maximum phase voltage and the minimum phase voltage to form the electrical loop among the midpoint of the bridge arm of the primary-side bridge arm circuit corresponding to the minimum phase voltage, the lower bridge arm circuit of the primary-side bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the upper bridge arm circuit of the primary-side bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage. It can be understood that the above electrical loop also includes units connected to the AC side, such as the power grid, AC equipment, AC power supply, etc. Referring to Figure 9 and Figure 10, taking the relationship of the current three-phase AC voltages as Ua > Ub > Uc, that is, the sector position is the first sector position and the second sector position as an example for illustration. The controller will control the operation of the primary bridge arm circuit corresponding to Ua and the operation of the primary bridge arm circuit corresponding to Uc, so that the inductor current, which is a negative current, will be transmitted in the electrical loop formed by the midpoint of the bridge arm of the primary bridge arm circuit corresponding to Uc and the lower bridge arm circuit, the primary side of the isolation circuit, and the midpoint of the bridge arm of the primary bridge arm circuit corresponding to Ua and the upper bridge arm circuit. At this time, the voltage across the inductor is uac + n·uBAT > 0, that is, a positive voltage. Since the direction of the inductor voltage applied across the inductor is opposite to the direction of the inductor current, based on the principle of volt-second balance, the inductor current will gradually decrease until it reaches zero. Thus, through the above settings, when the inductor current drops below a certain value, the controller can control all the switching tubes in the primary bridge arm switching circuit to be in a non-conducting state, so as to achieve the safe shutdown of the primary bridge arm switching circuit in the single-stage AC-DC conversion circuit, thereby improving the safety and stability of the single-stage AC-DC conversion circuit during the shutdown process.

[0074] In addition, in an embodiment, the controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the operation of the primary bridge arm circuit corresponding to the minimum phase voltage in response to the shutdown instruction, so as to form an electrical loop between the midpoints of their bridge arms and the primary side of the isolation circuit further includes: in response to the shutdown instruction, controlling the primary bridge arm circuits other than the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage among the three primary bridge arm circuits to be in a stopped working state. In this embodiment, it can be understood that for the primary bridge arm circuits other than the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage among the three primary bridge arm circuits, since they do not participate in the construction process of the above electrical loop, when the controller receives the shutdown instruction, it can directly control this primary bridge arm circuit to be in a stopped working state, that is, control all the switching tubes in this primary bridge arm circuit to be in a non-conducting state. In an example, referring to Figure 11 and Figure 5 , still taking u a > u b > u c as an example for illustration, when the controller receives the shutdown instruction, it will directly control the middle primary bridge arm circuit of the primary bridge arm switching circuit corresponding to ub to be in a stopped working state, that is, as shown in Figure 11 , drive signals with low levels are sent to the four switching tubes Qb1 - Qb4, so that the four switching tubes are all in a non-conducting state.

[0075] The control method of the single-stage AC-DC conversion circuit of the present application includes: obtaining the AC-side voltage; in response to a shutdown instruction, based on the AC-side voltage, controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage, so that an electrical loop is formed between the midpoints of the two bridge arms and the primary side of the isolation circuit, and in the electrical loop, the direction of the inductor current on the primary side of the isolation circuit is opposite to the direction of the inductor voltage. Through the above settings, when the single-stage AC-DC conversion circuit needs to shut down, the controller can control the operation of the above primary bridge arm circuit to form a corresponding electrical loop, and make the inductor current transmitted in the electrical loop and the inductor voltage applied across the inductor have opposite directions, so that the inductor current gradually decreases until it reaches zero. In this way, when the inductor current drops below a certain value, the controller can then control all the switching tubes in the primary bridge arm switching circuit to be in a non-conducting state, so as to achieve the safe shutdown of the primary bridge arm switching circuit in the single-stage AC-DC conversion circuit, thereby improving the safety and stability of the single-stage AC-DC conversion circuit during the shutdown process.

[0076] In an embodiment of the present application, the primary bridge arm circuit includes two bidirectional switch units electrically connected to each other, the midpoint of the bridge arm includes the connection point of the two bidirectional switch units, and the bidirectional switch unit includes an upper switching tube and a lower switching tube;

[0077] Optionally, referring to Figure 5 , in an embodiment, the diode modules in the upper switching tubes are arranged with their anodes facing each other with the diode modules in the lower switching tubes, and the controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage includes:

[0078] Controlling the upper switching tube in the upper bridge arm circuit and the lower switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in a conducting state, and controlling the lower switching tube in the upper bridge arm circuit and the upper switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in a conducting state;

[0079] Controlling the lower switching tube in the upper bridge arm circuit and the upper switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in a non-conducting state, and controlling the upper switching tube in the upper bridge arm circuit and the lower switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in a non-conducting state.

[0080] In this embodiment, in response to a shutdown instruction, the controller will send corresponding drive signals to all the upper and lower switching tubes in the primary bridge arm circuit corresponding to the maximum phase voltage and all the upper and lower switching tubes in the primary bridge arm circuit corresponding to the minimum phase voltage. In an example, referring to Figure 5 andFigure 12 , based on the above embodiments of determining the primary side bridge arm circuit corresponding to the maximum phase voltage and the primary side bridge arm circuit corresponding to the minimum phase voltage according to the sector position of the three-phase AC phase voltage, the R & D personnel can store Figure 12 the sector position - shutdown drive signal mapping table shown in Figure 6 in the controller. After determining the sector position where the current three-phase AC voltage is located in

[0081] during the process of the above embodiments, the controller can output corresponding drive signals to each upper switch tube and lower switch tube based on the above mapping table to control their states. Figure 5 It can be understood that, referring to Figure 5 , since the primary side bridge arm circuit is composed of two bidirectional switch units, and diode modules are provided corresponding to the anodes in the two upper and lower switch tubes of each bidirectional switch unit. Therefore, when the controller receives a shutdown instruction, it only needs to control the upper switch tube in the upper bridge arm circuit and the lower switch tube in the lower bridge arm circuit of the primary side bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state, and control the lower switch tube in the upper bridge arm circuit and the upper switch tube in the lower bridge arm circuit of the primary side bridge arm circuit corresponding to the minimum phase voltage to be in the conducting state; and, control the lower switch tube in the upper bridge arm circuit and the upper switch tube in the lower bridge arm circuit of the primary side bridge arm circuit corresponding to the maximum phase voltage to be in the non-conducting state, and control the upper switch tube in the upper bridge arm circuit and the lower switch tube in the lower bridge arm circuit of the primary side bridge arm circuit corresponding to the minimum phase voltage to be in the non-conducting state. Then, regardless of whether the direction of the current inductor current is positive or negative, a corresponding electrical loop can be adaptively formed on the

[0082] single-stage AC-DC conversion circuit shown in Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 and Figure 12 , taking the relationship of the current three-phase AC voltage as Ua>Ub>Uc, that is, the sector position is the first sector position and the second sector position as an example for illustration. Referring to Figure 7 and Figure 9 , after the controller outputs corresponding Figure 11 drive signals to each upper and lower switch tube based on the shutdown instruction, Qa1, Qa4, Qc2, and Qc3 are in the conducting state, and Qa2, Qa3, Qc1, and Qc2 are in the non-conducting state.

[0083] Referring toFigure 7 , if the inductor current is a positive current, then it will flow from the midpoint c of the bridge arm, through the diode modules of Qc2 and Qc1, the primary side of the isolation circuit, Qa4, the diode modules of Qa3, and the midpoint a of the bridge arm, thus forming an electrical loop to transmit the positive current on this electrical loop. At this time, the voltage across the inductor is uca-n·uBAT < 0, that is, a negative voltage, so the inductor current will gradually decrease.

[0084] Reference Figure 9 , if the inductor current is a negative current, then it will flow from the midpoint c of the bridge arm, through the diode modules of Qc3 and Qc4, the primary side of the isolation circuit, Qa1, the diode modules of Qa2, and the midpoint a of the bridge arm, thus forming an electrical loop to transmit the negative current on this electrical loop. At this time, the voltage across the inductor is uac+n·uBAT > 0, that is, a positive voltage, so the inductor current will gradually decrease.

[0085] Through the above settings, the control method of the single-stage AC-DC conversion circuit of the present application, when the single-stage AC-DC conversion circuit satisfies Figure 5 the circuit topology shown, there is no need to set an additional current detection component for detecting the direction of the inductor current in the single-stage AC-DC conversion circuit or in the device provided with the single-stage AC-DC conversion circuit. Only by controlling the corresponding upper and lower switching tubes can corresponding electrical loops be adaptively formed when the inductor current is positive or negative, thus not only realizing the reduction of the inductor current at the stop moment, but also streamlining the circuit architecture and reducing the cost of the entire circuit and the device provided with the circuit. In addition, it can be understood that during the actual operation control of the single-stage AC-DC conversion circuit shown in Figure 5 , since four switching tubes in the primary side bridge arm circuit corresponding to its maximum phase voltage and minimum phase voltage are always in the conducting state, when the controller outputs the corresponding drive signal waveform in response to the stop command, there is no need to change the drive signals of the four switching tubes that were originally in the conducting state. Only the remaining switching tubes in the primary side bridge arm circuit corresponding to the maximum phase voltage and minimum phase voltage need to be controlled to be in the non-conducting state. For example, refer to Figure 12 , Figure 12 is a schematic diagram of the drive signals issued by the controller for each switching tube corresponding to the above Figure 7 and Figure 9 cases. At the stop moment t1, Qa1, Qa4, Qc2, and Qc3 that were originally in the conducting state will continue to be in the conducting state, and the others will be in the non-conducting state. With such a setting, the response time of the controller at the stop moment is effectively reduced, thereby reducing the stop time required for the primary side bridge arm circuit of the single-stage AC-DC conversion circuit.

[0086] Similarly, in another embodiment, the cathodes of the diode modules in the upper switching tube and the diode modules in the lower switching tube are arranged opposite to each other. Controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage includes:

[0087] Controlling the upper switching tube in the upper bridge arm circuit and the lower switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in the conducting state, and controlling the lower switching tube in the upper bridge arm circuit and the upper switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state;

[0088] Controlling the lower switching tube in the upper bridge arm circuit and the upper switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in the non-conducting state, and controlling the upper switching tube in the upper bridge arm circuit and the lower switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the non-conducting state.

[0089] In this embodiment, in each bidirectional switch unit, the cathodes of the diode modules in the upper switching tube and the diode modules in the lower switching tube are arranged opposite to each other. Therefore, when the controller responds to the stop instruction, corresponding drive signals will be sent to the four switching tubes in the primary bridge arm circuit corresponding to the minimum phase voltage and the four switching tubes in the primary bridge arm circuit corresponding to the maximum phase voltage, so that the upper switching tube in the upper bridge arm circuit and the lower switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage are in the conducting state, and controlling the lower switching tube in the upper bridge arm circuit and the upper switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state; and, making the lower switching tube in the upper bridge arm circuit and the upper switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage be in the non-conducting state, and controlling the upper switching tube in the upper bridge arm circuit and the lower switching tube in the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the non-conducting state. With such a setting, the control method of this embodiment can achieve the same technical effect as the embodiment in which the anodes of the diode modules of the upper and lower switching tubes are arranged opposite to each other, that is, no additional current detection component is required, and an appropriate electrical circuit can be automatically formed adaptively when the inductor current is a positive current or a negative current, so as to achieve the effect of reducing the inductor current. Other effects and control processes can refer to the above embodiment, and will not be elaborated here.

[0090] Refer to Figure 3 , in another embodiment of the present application, controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to form an electrical circuit between the midpoints of the bridge arms and the primary side of the isolation circuit includes:

[0091] Step S230, obtaining the inductor current on the primary side of the isolation circuit;

[0092] Step S240: When the inductor current is a positive current, control the upper-arm circuit of the primary-side bridge arm corresponding to the minimum phase voltage and the lower-arm circuit of the primary-side bridge arm corresponding to the maximum phase voltage to be both in the conducting state, so as to form an electrical loop among the midpoint of the bridge arm of the primary-side bridge arm corresponding to the minimum phase voltage, the upper-arm circuit of the primary-side bridge arm corresponding to the minimum phase voltage, the primary side of the isolation circuit, the lower-arm circuit of the primary-side bridge arm corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage;

[0093] Step S250: When the inductor current is a negative current, control the lower-arm circuit of the primary-side bridge arm corresponding to the minimum phase voltage and the upper-arm circuit of the primary-side bridge arm corresponding to the maximum phase voltage to be both in the conducting state, so as to form an electrical loop among the midpoint of the bridge arm of the primary-side bridge arm corresponding to the minimum phase voltage, the lower-arm circuit of the primary-side bridge arm corresponding to the minimum phase voltage, the primary side of the isolation circuit, the upper-arm circuit of the primary-side bridge arm corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage.

[0094] In this embodiment, in a single-stage AC-DC conversion circuit or a device provided with a single-stage AC-DC conversion circuit, a current detection component for detecting the inductor current on the primary side of the isolation circuit may also be provided. Optionally, the current detection component is implemented by a current detection module; optionally, the current detection component may also be implemented by a current detection circuit composed of a current detection resistor, a Hall device, or a magnetic device. The controller may determine the direction and value of the inductor current on the primary side of the isolation circuit based on the result detected by the current detection component.

[0095] When the controller determines that the inductor current is a positive current, corresponding drive signals are respectively output to the primary-side bridge arm circuit corresponding to the minimum phase voltage and the primary-side bridge arm circuit corresponding to the maximum phase voltage in the primary-side bridge arm switching circuit, so that the upper-arm circuit of the primary-side bridge arm corresponding to the minimum phase voltage and the lower-arm circuit of the primary-side bridge arm corresponding to the maximum phase voltage are both in the conducting state. At the same time, it can be understood that based on the well-known common sense of control in the art, to prevent a short circuit caused by the simultaneous conduction of the upper and lower arms in the primary-side bridge arm circuit, the controller will also control the lower-arm circuit of the primary-side bridge arm corresponding to the minimum phase voltage and the upper-arm circuit of the primary-side bridge arm corresponding to the maximum phase voltage to be in the non-conducting state. Thus, at this time, the voltage applied across the inductor is a negative voltage, opposite to the direction of the inductor current which is a positive current, and the inductor current will gradually decrease.

[0096] Similarly, when the controller determines that the inductor current is a negative current, it controls the lower arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage and the upper arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be both in the conducting state. At the same time, it can be understood that based on the common knowledge of control in the art, to prevent a short circuit caused by the simultaneous conduction of the upper and lower arms in the primary bridge arm circuit, the controller will also control the upper arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage and the lower arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the non-conducting state at this time. In this way, the voltage applied across the inductor is a positive voltage, which is opposite to the direction of the inductor current that is a negative current, and the inductor current will gradually decrease.

[0097] Through the above settings, for a single-stage AC-DC conversion circuit that does not have the ability of the bidirectional switch unit in the primary bridge arm switch circuit in the above embodiments to form a corresponding electrical circuit loop both when the inductor current is a positive current or a negative current with only one set of control logic. For example, the primary bridge arm circuit uses two switching devices to implement so that the primary bridge arm switch circuit only has the ability of single-phase frequency conversion, or the primary bridge arm circuit is not composed of the two bidirectional switch units in the above embodiments. Therefore, in order to ensure the formation of a corresponding electrical circuit loop based on the inductor current, in this embodiment, the controller can determine the specific situation of the inductor current through the current detection component, and thus adaptively control the operation of the primary bridge arm circuits corresponding to the maximum phase voltage and the minimum phase voltage to form a corresponding electrical circuit loop to reduce the inductor current, and further enable the safe shutdown of the primary bridge arm switch circuit in such a single-stage AC-DC conversion circuit to still have the ability of safe shutdown, effectively improving the safety and stability of the single-stage AC-DC conversion circuit during the shutdown process.

[0098] In addition, it can be understood that for the single-stage AC-DC conversion circuit corresponding to the embodiment in which the primary bridge arm circuit consists of two bidirectional switch units, the controller can also perform adaptive control on multiple switching tubes in the primary bridge arm circuit based on the results detected by the current detection component currently.

[0099] It should be understood that during the process of the above embodiments, the inductor current will gradually decrease. After decreasing to a certain extent, the primary bridge arm switch circuit of the single-stage AC-DC conversion circuit can be controlled to be all in the stopped working state to achieve the shutdown of the primary bridge arm switch circuit of the single-stage AC-DC conversion circuit.

[0100] For this reason, based on any of the above embodiments, optionally, in an embodiment of the present application, refer to Figure 4, after operating the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to form an electrical loop between the midpoints of the bridge arms of the two and the primary side of the isolation circuit and with the directions of the inductor current and inductor voltage on the primary side of the isolation circuit being opposite in the electrical loop, the method further includes:

[0101] Step S300, after a preset first duration, control the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to both be in a stopped working state.

[0102] In this embodiment, the preset first duration can be preset by the R & D personnel in the controller. Among them, in one example, the preset first duration can be a duration greater than or equal to one switching period; in another example, during R & D, the R & D personnel can actually test the time taken for the inductor current to drop to a preset first current threshold (which can be set by the R & D personnel) or to zero after the controller executes the above actions, and based on the results of multiple tests, determine the final preset first duration. For example, take the maximum duration among multiple test durations as the preset first duration. Thus, after the controller operates the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to form an electrical loop between the midpoints of the bridge arms of the two and the primary side of the isolation circuit and with the directions of the inductor current and inductor voltage on the primary side of the isolation circuit being opposite in the electrical loop, it will start timing, and after the timing duration reaches the preset first duration, it is determined that the current inductor current has dropped to a safe value. At this time, it will control the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to both be in a stopped working state, that is, control all the switching tubes in the two primary bridge arm circuits to be in a non-conducting state, thereby completing the shutdown operation of the primary bridge arm switching circuit of the single-stage AC-DC conversion circuit.

[0103] Optionally, in another embodiment, after the step of, in response to a shutdown instruction, controlling the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to operate so as to form an electrical loop between the midpoints of the bridge arms of the two and the primary side of the isolation circuit, the method further includes:

[0104] Obtain the inductor current on the primary side of the isolation circuit;

[0105] When the inductor current is less than a preset first current threshold, control the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to both be in a stopped working state.

[0106] In this embodiment, in a single-stage AC-DC conversion circuit or a device provided with a single-stage AC-DC conversion circuit, a current detection component electrically connected to the controller is further provided, and the current detection component can be implemented with reference to the same embodiment in the above-mentioned embodiment. The controller can determine the current value of the inductor current on the primary side of the isolation circuit based on the detection result of the current detection component, and when the inductor current is less than a preset first current threshold (the preset first current threshold can be set by the R & D personnel themselves, for example, set to a value approaching 0), it is determined that the current inductor current has dropped to a safe value. At this time, it will control the primary side bridge arm circuit corresponding to the maximum phase voltage and the primary side bridge arm circuit corresponding to the minimum phase voltage to be in a stopped working state, that is, control all the switching tubes in the two primary side bridge arm circuits to be in a non-conducting state, thereby completing the shutdown operation of the primary side bridge switch circuit of the single-stage AC-DC conversion circuit.

[0107] This application also proposes a controller, including: a memory, a processor, and a control program of a single-stage AC-DC conversion circuit stored on the memory and executable on the processor, and the control program of the single-stage AC-DC conversion circuit is configured to implement the control method of the single-stage AC-DC conversion circuit as described in any one of the above.

[0108] It should be noted that since this application includes the control method of the above single-stage AC-DC conversion circuit. Therefore, all the technical solutions included in this application also at least have all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0109] This application also proposes a power module, including the control method of the single-stage AC-DC conversion circuit as described in any one of the above; and / or, the controller as described above.

[0110] In this embodiment, the power module includes an on-vehicle charger or other types of power modules.

[0111] It should be noted that since this application includes the control method and / or controller of the above single-stage AC-DC conversion circuit. Therefore, all the technical solutions included in this application also at least have all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0112] The above content is only an embodiment of this application, and does not limit the patent scope of this application. All equivalent structural transformations made under the application concept of this application by using the content of the specification and drawings of this application, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of this application.

Claims

1. Control method of single-stage AC-DC conversion circuit, the single-stage AC-DC conversion circuit includes a primary side bridge arm switching circuit, an isolation circuit and a secondary side bridge arm switching circuit, the primary side bridge arm switching circuit includes three primary side bridge arm circuits, the midpoints of the bridge arms of the three primary side bridge arm circuits are used for electrically connecting to the AC side, the first ends of the three primary side bridge arm circuits are respectively connected to the first end of the primary side of the isolation circuit, and the second ends of the three primary side bridge arm circuits are respectively connected to the second end of the primary side of the isolation circuit; characterized in that, The control method of the single-stage AC-DC conversion circuit includes: Obtaining the AC-side voltage; In response to a shutdown instruction, based on the AC-side voltage, controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage, so that an electrical loop is formed between the midpoints of the two bridge arms and the primary side of the isolation circuit, and in the electrical loop, the direction of the inductor current on the primary side of the isolation circuit is opposite to the direction of the inductor voltage.

2. The control method of the single-stage AC-DC conversion circuit according to claim 1, characterized in that The obtaining of the AC-side voltage includes: Obtaining the operating mode and determining the AC-side voltage based on the operating mode; Wherein, the operating mode includes a rectification mode, a V2G inversion mode, and a V2L inversion mode; In the case where the operating mode is the rectification mode and the V2G inversion mode, the AC-side voltage includes the AC voltage of the AC power supply connected to the AC side; In the case where the operating mode is the V2L inversion mode, the AC-side voltage includes the AC voltage output from the primary bridge arm switch circuit to the AC side.

3. The control method of the single-stage AC-DC conversion circuit according to claim 1, wherein The controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage based on the AC-side voltage includes: Based on the AC-side voltage, determining the sector position where the AC-side voltage is located in a preset AC voltage sector; Based on the sector position, controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage; wherein, the preset AC voltage sector includes a three-phase AC line voltage sector or a three-phase AC phase voltage sector.

4. The control method of the single-stage AC-DC conversion circuit according to claim 1, characterized in that, The formation of the electrical loop between the midpoints of the two bridge arms and the primary side of the isolation circuit includes; When the inductor current on the primary side of the isolation circuit is a positive current, an electrical loop is formed between the midpoint of the primary bridge arm circuit corresponding to the minimum phase voltage, the upper bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the lower bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage; When the current on the primary side of the isolation circuit is a negative current, an electrical loop is formed between the midpoint of the primary bridge arm circuit corresponding to the minimum phase voltage, the lower bridge arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the upper bridge arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage.

5. The control method of the single-stage AC-DC conversion circuit according to claim 4, characterized in that, The primary bridge arm circuit includes two bidirectional switch units electrically connected to each other, the bridge arm midpoint includes the connection point of the two bidirectional switch units, and the bidirectional switch unit includes an upper switch tube and a lower switch tube; The diode modules in the upper switch tubes are arranged with their anodes facing each other with the diode modules in the lower switch tubes, and the controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage includes: Control the upper switch in the upper arm circuit and the lower switch in the lower arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state, and control the lower switch in the upper arm circuit and the upper switch in the lower arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in the conducting state; Control the lower switch in the upper arm circuit and the upper switch in the lower arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the non-conducting state, and control the upper switch in the upper arm circuit and the lower switch in the lower arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in the non-conducting state; Or, The cathode of the diode module in the upper switch is arranged opposite to the cathode of the diode module in the lower switch. The actions of controlling the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage include: Control the upper switch in the upper arm circuit and the lower switch in the lower arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in the conducting state, and control the lower switch in the upper arm circuit and the upper switch in the lower arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state; Control the lower switch in the upper arm circuit and the upper switch in the lower arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage to be in the non-conducting state, and control the upper switch in the upper arm circuit and the lower switch in the lower arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the non-conducting state.

6. The control method of the single-stage AC-DC conversion circuit according to claim 4, characterized in that The actions of controlling the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to form an electrical loop between the midpoints of the bridge arms and the primary side of the isolation circuit include: Obtain the inductor current on the primary side of the isolation circuit; When the inductor current is a positive current, control both the upper arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage and the lower arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state, so as to form the electrical loop between the midpoint of the bridge arm of the primary bridge arm circuit corresponding to the minimum phase voltage, the upper arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the lower arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage; When the inductor current is a negative current, control both the lower arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage and the upper arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage to be in the conducting state, so as to form the electrical loop between the midpoint of the bridge arm of the primary bridge arm circuit corresponding to the minimum phase voltage, the lower arm circuit of the primary bridge arm circuit corresponding to the minimum phase voltage, the primary side of the isolation circuit, the upper arm circuit of the primary bridge arm circuit corresponding to the maximum phase voltage, and the midpoint of the bridge arm corresponding to the maximum phase voltage.

7. The control method of the single-stage AC-DC conversion circuit according to any one of claims 1-6, characterized in that, In response to a shutdown instruction, controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage, so that an electrical loop is formed between the midpoints of the two bridge arms and the primary side of the isolation circuit, further includes: In response to a shutdown instruction, controlling the primary bridge arm circuits other than the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage among the three primary bridge arm circuits to be in a stopped working state.

8. The control method of the single-stage AC-DC conversion circuit according to any one of claims 1-6, characterized in that, After controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage so that an electrical loop is formed between the midpoints of the two bridge arms and the primary side of the isolation circuit and the directions of the inductor current and the inductor voltage on the primary side of the isolation circuit in the electrical loop are opposite, the method further includes: After a preset first time period, controlling both the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to be in a stopped working state; or, After the step of, in response to a shutdown instruction, controlling the operation of the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage so that an electrical loop is formed between the midpoints of the two bridge arms and the primary side of the isolation circuit, the method further includes: Obtaining the inductor current on the primary side of the isolation circuit; When the inductor current is less than a preset first current threshold, controlling both the primary bridge arm circuit corresponding to the maximum phase voltage and the primary bridge arm circuit corresponding to the minimum phase voltage to be in a stopped working state.

9. A controller, characterized in that, The controller includes: a memory, a processor, and a control program of a single-stage AC-DC conversion circuit stored on the memory and executable on the processor, and the control program of the single-stage AC-DC conversion circuit is configured to implement the control method of the single-stage AC-DC conversion circuit as described in any one of claims 1 to 8 above.

10. A power supply module, characterized in that, Including the control method of the single-stage AC-DC conversion circuit as described in any one of claims 1-8; and / or, the controller as described in claim 9.

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