Isolation matrix converter and control method

Abstract

The present application discloses a separation matrix converter and a control method, the converter includes a bidirectional switch module, a transformer, a resonant inductor, a resonant capacitor, and a bridge arm capacitor, the bidirectional switch module is connected in series with the bridge arm capacitor to form a bridge arm of the converter, each bridge arm of the converter includes at least one bidirectional switch module, the primary winding of the transformer is connected in series with the resonant inductor and the resonant capacitor and then connected to both ends of the bridge arm of the converter, the bidirectional switch module includes a clamp capacitor and a bidirectional switch unit, the bidirectional switch unit forms two bridge arms of the module, both ends of the clamp capacitor are connected to both ends of the two bridge arms of the module, the clamp capacitor forms a clamp absorption circuit with the two upper bridge arms or the two lower bridge arms of the two bridge arms, the bidirectional switch unit includes at least two controllable switching tubes, the clamp capacitor suppresses voltage spikes generated when the switching tubes in the bidirectional switch module are operated, thereby protecting the switching tubes, further protecting the safety of the entire converter, and improving the reliability of the entire converter.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to a Chinese patent application bearing application number 202210565545.1 and entitled "Isolation Matrix Converter and Control Method," filed with the State Intellectual Property Office of the People's Republic of China on May 23, 2022, the entire contents of which are incorporated herein by reference. [Technical field] The present application relates to the technical field of power electronics, and in particular to an isolated matrix converter and a control method. [Background technology]

[0002] The isolation matrix converter generally includes a bidirectional switch and a transformer, and the input end of the transformer further includes a resonant circuit. Generally, the isolation matrix converter can realize AC to AC conversion and AC to DC conversion. For example, the input is AC and the output is DC.

[0003] Please refer to FIG. 1, which is a schematic diagram of an isolated matrix converter provided by the prior art.

[0004] As shown in Figure 1, the input terminal of this isolation matrix converter is connected to a three-phase AC power supply. Each phase of the isolation matrix converter includes a bidirectional switch. The anti-parallel diodes of the two series-connected switching tubes are reversed, allowing current to flow in both directions. The primary winding of the transformer is connected in series with an inductor and a capacitor to form LLC resonance. However, the voltage clamp of the bidirectional switch in the isolation matrix converter shown in Figure 1 is the line voltage of the AC power. When passing through the resonance region, the switching tube experiences a large current switching. This voltage spike can be too high and cause overvoltage failure of the switching tube. Summary of the Invention [Problem to be solved by the invention]

[0005] In view of this, the embodiments of the present application provide an isolated matrix converter and a control method that can suppress voltage spikes caused when a switching tube operates and protect the switching tube. [Means for solving the problem]

[0006] The present application provides an isolation matrix converter, which includes a bidirectional switch module, a transformer, a resonant inductor, a resonant capacitor, and a bridge arm capacitor; the bidirectional switch module is connected in series with the bridge arm capacitor to form a bridge arm of the converter, and each bridge arm of the converter includes at least one bidirectional switch module; a primary winding of the transformer is connected in series with the resonant inductor and the resonant capacitor, and then connected to both ends of a bridge arm of the converter; The bidirectional switch module includes a clamp capacitor and a bidirectional switch unit, the bidirectional switch unit forms two bridge arms of the module, both ends of the clamp capacitor are connected to both ends of the two bridge arms of the module, the clamp capacitor forms a clamp absorption circuit with two upper bridge arms or two lower bridge arms of the two bridge arms, and the bidirectional switch unit includes at least two controllable switching tubes; The clamp capacitor is used to suppress voltage spikes that occur when the switching tube in the bidirectional switch module operates.

[0007] Preferably, when the bidirectional switch module includes two controllable switching tubes, the two controllable switching tubes are located in the same two upper bridge arms or the same two lower bridge arms.

[0008] Preferably, the bidirectional switch module includes four controllable switching tubes, namely, a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube; a first end of the first switching tube and a first end of the third switching tube are both connected to a first end of the clamp capacitor, a second end of the second switching tube and a second end of the fourth switching tube are both connected to a second end of the clamp capacitor, a second end of the first switching tube is connected to the first end of the second switching tube, and a second end of the third switching tube is connected to the first end of the fourth switching tube; The common end of the first switching tube and the second switching tube is a first end of the bidirectional switch module, and the common end of the third switching tube and the fourth switching tube is a second end of the bidirectional switch module.

[0009] Preferably, the bidirectional switch module includes three controllable switching tubes, namely, a first switching tube, a second switching tube, and a third switching tube, and one diode, namely, a first diode; The first switching tube and the second switching tube are connected in series to form a first bridge arm of the module, and the third switching tube and the first diode are connected in series to form a second bridge arm of the module.

[0010] Preferably, the bidirectional switch module includes two controllable switching tubes, a first switching tube and a second switching tube, and two diodes, a first diode and a second diode; The first switching tube and the first diode are connected in series to form a first bridge arm of the module, and the second switching tube and the second diode are connected in series to form a second bridge arm of the module.

[0011] Preferably, the converter includes at least two bidirectional switch modules connected in series; The converter further includes a controller, and the controller specifically controls and operates the controllable switching tube in the bidirectional switch unit to discharge the clamp capacitor until the voltage of the clamp capacitor is smaller than a second preset voltage when the voltage of the clamp capacitor is larger than a first preset voltage, thereby balancing the voltage between the at least two bidirectional switch modules, and the first preset voltage is larger than the second preset voltage.

[0012] Preferably, the converter includes at least two bidirectional switch modules connected in series; The converter further includes a controller, and the controller specifically controls and operates a controllable switching tube in the bidirectional switch unit to charge the clamp capacitor until the voltage of the clamp capacitor is greater than a fourth preset voltage when the voltage of the clamp capacitor is less than a third preset voltage, thereby balancing the voltages between the at least two bidirectional switch modules; The third preset voltage is less than the fourth preset voltage.

[0013] Preferably, when the isolated matrix converter is a three-phase isolated matrix converter, each phase of the three-phase isolated matrix converter includes at least one bidirectional switch module; The converter further includes a controller, and the controller further controls the switching tube that is not subjected to a voltage stress of a phase having the highest absolute value of a phase voltage to always be turned on, and the switching tube that is subjected to the voltage stress of the highest phase to perform a switching operation at a preset duty ratio; The controller further controls the switching tube of the phase having the second highest absolute value of the phase voltage, which is not subjected to voltage stress when the switching tube of the highest phase is turned on, to turn on before the bidirectional switch module of the highest phase is turned off, and the switching tube of the second highest phase, which is subjected to voltage stress, to turn on after the bidirectional switch module of the highest phase is turned off; The controller further controls the switching tube that is not subjected to voltage stress when the bidirectional switch module of the second highest phase, which is the phase having the smallest absolute value of the phase voltage, is turned on so that it turns on before the bidirectional switch module of the second highest phase is turned off, and the switching tube that is subjected to voltage stress turns on after the bidirectional switch module of the second highest phase is turned off.

[0014] Preferably, when the bridge arm of each of the converters includes a plurality of the bidirectional switch units, the plurality of bidirectional switch units are connected in series.

[0015] Preferably, the secondary winding of the transformer is connected to a rectifier bridge, the rectifier bridge including at least one of a diode or a controllable switching tube.

[0016] Preferably, the transformer includes a plurality of secondary windings, each secondary winding being connected to a corresponding rectifier bridge.

[0017] The present application further provides a control method for an isolated matrix converter, the isolated matrix converter including a bidirectional switch module, a transformer, a resonant inductor, a resonant capacitor, and a bridge arm capacitor, the bidirectional switch module being connected in series with the bridge arm capacitor to form a bridge arm of the converter, each bridge arm of the converter including at least one bidirectional switch module, a primary winding of the transformer being connected in series with the resonant inductor and the resonant capacitor and then connected to both ends of the bridge arm of the converter, the bidirectional switch module including a clamp capacitor and a bidirectional switch unit, the bidirectional switch unit forming two bridge arms of the module, both ends of the clamp capacitor being connected to both ends of the two bridge arms of the module, the clamp capacitor forming a clamp absorption circuit with two upper bridge arms or two lower bridge arms of the two bridge arms, the bidirectional switch unit including at least two controllable switching tubes, The method comprises: controlling and operating a switching tube in the bidirectional switch module; and controlling the clamp capacitor to suppress voltage spikes during operation of a switching tube in the bidirectional switch module.

[0018] Preferably, when the bidirectional switch module includes two controllable switching tubes, the two controllable switching tubes are located in the same two upper bridge arms or the same two lower bridge arms.

[0019] Preferably, the bidirectional switch module includes four controllable switching tubes, namely, a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube; a first end of the first switching tube and a first end of the third switching tube are both connected to a first end of the clamp capacitor, a second end of the second switching tube and a second end of the fourth switching tube are both connected to a second end of the clamp capacitor, a second end of the first switching tube is connected to the first end of the second switching tube, and a second end of the third switching tube is connected to the first end of the fourth switching tube; The common end of the first switching tube and the second switching tube is a first end of the bidirectional switch module, and the common end of the third switching tube and the fourth switching tube is a second end of the bidirectional switch module.

[0020] Preferably, the converter includes at least two bidirectional switch modules connected in series; The method further includes controlling and operating a controllable switching tube in the bidirectional switch unit to discharge the clamp capacitor until the voltage of the clamp capacitor is less than a second preset voltage when the voltage of the clamp capacitor is greater than a first preset voltage, thereby balancing the voltage between the at least two bidirectional switch modules, wherein the first preset voltage is greater than the second preset voltage.

[0021] Preferably, the converter includes at least two bidirectional switch modules connected in series; When the voltage of the clamp capacitor is smaller than a third preset voltage, controlling and operating a controllable switching tube in the bidirectional switch unit to charge the clamp capacitor until the voltage of the clamp capacitor is greater than a fourth preset voltage, thereby balancing the voltage between the at least two bidirectional switch modules; The third preset voltage is less than the fourth preset voltage.

[0022] Preferably, when the isolated matrix converter is a three-phase isolated matrix converter, each phase of the three-phase isolated matrix converter includes at least one bidirectional switch module; The method comprises: controlling the switching tube that is not subjected to the voltage stress of the phase having the highest absolute value of the phase voltage to always be on, and the switching tube that is subjected to the voltage stress of the highest phase to perform a switching operation at a preset duty ratio; Controlling the phase having the second highest absolute value of phase voltage so that the switching tube that is not subjected to voltage stress when the highest phase switching tube is turned on is turned on before the highest phase bidirectional switch module is turned off, and the switching tube that is subjected to voltage stress of the second highest phase is turned on after the highest phase bidirectional switch module is turned off; The method further includes a step of controlling the switching tube that is not subjected to voltage stress when the bidirectional switch module of the second highest phase, which is the phase having the smallest absolute value of the phase voltage, is turned on so that it turns on before the bidirectional switch module of the second highest phase is turned off, and the switching tube that is subjected to voltage stress turns on after the bidirectional switch module of the second highest phase is turned off.

[0023] As such, the embodiment of the present application has the following beneficial effects. The isolation matrix converter includes a bidirectional switch module, the bidirectional switch module including a clamp capacitor and a bidirectional switch unit, the bidirectional switch unit forming two bridge arms of the module, both ends of the clamp capacitor connected to both ends of the two bridge arms of the module, the clamp capacitor forming a clamp absorption circuit with the two upper bridge arms or the two lower bridge arms of the two bridge arms, the bidirectional switch unit including at least two controllable switching tubes, the clamp capacitor capable of suppressing voltage spikes generated by the switching tubes during operation, thereby protecting the switching tubes and further protecting the safety and reliability of the entire converter. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic diagram of an isolated matrix converter provided by the prior art; [Figure 2] FIG. 1 is a schematic diagram of an isolated matrix converter provided by an embodiment of the present application. [Figure 3] FIG. 10 is a schematic diagram of yet another isolated matrix converter provided by an embodiment of the present application. [Figure 4] FIG. 1 is a schematic diagram of a bidirectional switch module provided by an embodiment of the present application. [Figure 5] FIG. 10 is a schematic diagram of yet another bidirectional switch module provided by an embodiment of the present application. [Figure 6] FIG. 10 is a schematic diagram of another bidirectional switch module provided by an embodiment of the present application. [Figure 7] FIG. 10 is a schematic diagram of another bidirectional switch module provided by an embodiment of the present application. [Figure 8] FIG. 10 is a schematic diagram of yet another isolated matrix converter provided by an embodiment of the present application. [Figure 9] FIG. 10 is a schematic diagram of another isolated matrix converter provided by an embodiment of the present application. [Figure 10] 1 is an oscillogram of a three-phase AC voltage provided by an embodiment of the present application. [Figure 11] FIG. 10 is a driving timing diagram of a bidirectional switch module of an isolated matrix converter provided by an embodiment of the present application. [Figure 12A] 1 is a diagram illustrating the operation principle of the switching operation in the bidirectional switch module provided by the embodiment of the present application; [Figure 12B] 1 is a diagram illustrating the operation principle of the switching operation in the bidirectional switch module provided by the embodiment of the present application; [Figure 12C] 1 is a diagram illustrating the operation principle of the switching operation in the bidirectional switch module provided by the embodiment of the present application; [Figure 12D] 1 is a diagram illustrating the operation principle of the switching operation in the bidirectional switch module provided by the embodiment of the present application; [Figure 13] FIG. 10 is a voltage stress schematic diagram of the turn-off process of Q4 provided by an embodiment of the present application. [Figure 14] 1 is a flowchart of a control method for an isolated matrix converter provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0025] In order to help those skilled in the art better understand the technical solution provided by this application, a specific application scenario will be first introduced below.

[0026] The isolated matrix converter provided by the embodiments of the present application may be a DC-AC-DC converter or an AC-AC-DC converter, i.e., the input may be DC or AC, but the output is generally DC. Also, the input may be three-phase or one-phase, and the output may be one-phase, i.e., it outputs DC to a load.

[0027] The isolated matrix converter provided by the embodiments of the present application is not limited to a specific application scenario. For example, if the transformer of the isolated matrix converter has multiple secondary windings, each secondary winding can be connected to a rectifier bridge, and the output of each rectifier bridge can be connected to a load, such as charging for new energy vehicles, that is, applied to a charging pile scenario, and each output can be connected to a charging gun to provide DC charging for the new energy vehicles.

[0028] The isolation matrix converter may also provide power for other electrical equipment, for example electrical use in a machine room such as a server.

[0029] Furthermore, if the rectifier bridge connected to the secondary winding of the transformer of the isolation matrix converter includes a controllable switching tube, the isolation matrix converter may be a bidirectional converter, i.e., energy can flow in both directions, for example, converting DC to AC or AC to DC.

[0030] Converter implementation example The isolated matrix converter provided by the embodiment of the present application will be described in detail below with reference to the accompanying drawings, taking a three-phase AC input as an example.

[0031] Please refer to FIG. 2, which is a schematic diagram of an isolation matrix converter provided by an embodiment of the present application.

[0032] The isolation matrix converter provided in this embodiment includes a bidirectional switch module 100, a transformer Tx, a resonant inductor Lr, a resonant capacitor Cr, and a bridge arm capacitor. As shown in FIG. 2 , taking a three-phase AC input as an example, the isolation matrix converter corresponds to a three-phase bridge arm, where the bridge arm capacitor of phase A is CA, the bridge arm capacitor of phase B is CB, and the bridge arm capacitor of phase C is CC.

[0033] The bidirectional switch modules 100 are connected in series to the bridge arm capacitors to form the bridge arms of the converter. Each bridge arm of the isolation matrix converter includes at least one bidirectional switch module. The embodiments of the present application do not specifically limit the number of bidirectional switch modules 100 included in each phase bridge arm. In FIG. 2, each phase bridge arm includes multiple bidirectional switch modules 100 connected in series. For example, the n bidirectional switch modules of the A-phase bridge arm are MA1 to MAn, respectively. By the same principle, the n bidirectional switch modules of the B-phase bridge arm are MB1 to MBn, respectively, and the n bidirectional switch modules of the C-phase bridge arm are MC1 to MCn, respectively. n is an integer greater than or equal to 1.

[0034] The upper half bridge arm of each phase of the isolated matrix converter is a bidirectional switch module, and the lower half bridge arm is a bridge arm capacitor. The bidirectional switch module is connected in series with the bridge arm capacitor to form the entire bridge arm of each phase.

[0035] The primary winding of the transformer is connected in series to the resonant inductor Lr and the resonant capacitor Cr and connected to both ends of the bridge arm of the isolation matrix converter, and the primary winding of the transformer is connected in series to the resonant inductor Lr and the resonant capacitor Cr to form LLC series resonance.

[0036] The bidirectional switch module includes a clamp capacitor and a bidirectional switch unit, the bidirectional switch unit forms two bridge arms of the module, both ends of the clamp capacitor are connected to both ends of the two bridge arms of the module, the clamp capacitor forms a clamp absorption circuit with two upper bridge arms or two lower bridge arms of the two bridge arms, and the bidirectional switch unit includes at least two controllable switching tubes; The clamp capacitor is used to suppress voltage spikes generated by the switching tube in the bidirectional switch unit during its operation.

[0037] The bidirectional switch module in the isolation matrix converter provided by the embodiments of the present application must include at least two controllable switching tubes, i.e., it may include four, three, or two, but including only one controllable switching tube will not enable charging and discharging of the clamp capacitor. If the bidirectional switch module includes two controllable switching tubes, the two controllable switching tubes must be located in the same two upper bridge arms or two lower bridge arms.

[0038] 2, the bidirectional switch module is shown to include four controllable switching tubes, namely, a first switching tube Q1, a second switching tube Q2, a third switching tube Q3, and a fourth switching tube Q4. To form a free-wheeling loop, each switching tube includes an anti-parallel diode, i.e., the anti-parallel diode of the first switching tube Q1 is D1, the anti-parallel diode of the second switching tube Q2 is D2, the anti-parallel diode of the third switching tube Q3 is D3, and the anti-parallel diode of the fourth switching tube Q4 is D4.

[0039] a first end of the first switching tube Q1 and a first end of the third switching tube Q3 are both connected to a first end of the clamp capacitor C1; a second end of the second switching tube Q2 and a second end of the fourth switching tube Q4 are both connected to a second end of the clamp capacitor C1; a second end of the first switching tube Q1 is connected to a first end of the second switching tube Q2; and a second end of the third switching tube Q3 is connected to a first end of the fourth switching tube Q4; The common end of the first switching tube Q1 and the second switching tube Q2 is the first end of the bidirectional switch module, and the common end of the third switching tube Q3 and the fourth switching tube Q4 is the second end of the bidirectional switch module.

[0040] 2, the output terminal of the isolation matrix converter is connected to a full-bridge rectifier bridge, and the rectifier bridge includes four diodes, namely, a fourth diode D4, a fifth diode D5, a sixth diode D6, and a seventh diode D7. The fourth diode D4 and the fifth diode D5 are connected in series to form one bridge arm of the rectifier bridge, and the sixth diode D6 and the seventh diode D7 are connected in series to form the other bridge arm of the rectifier bridge. The output terminal of the rectifier bridge is connected to the output capacitor Cbus.

[0041] 2 only shows that the rectifier bridge includes diodes, but the rectifier bridge may also include controllable switching tubes or a combination of controllable switching tubes and diodes. If the bridge arms of the rectifier bridge include controllable switching tubes, the isolation matrix converter can achieve bidirectional power conversion, i.e., DC to AC conversion. One side of the rectifier bridge is the input end.

[0042] In FIG. 2, if each phase bridge arm includes only one bidirectional switch module, as shown in FIG. 3, this figure is a schematic diagram of yet another isolated matrix converter provided by an embodiment of the present application.

[0043] In FIG. 3, each phase bridge arm includes only one bidirectional switch module, and the rest is the same as in FIG. 2, and will not be described here.

[0044] The bidirectional switch modules in FIGS. 2 and 3 are all controllable switching tubes, and the following will introduce a case where a combination of controllable switching tubes and diodes is included.

[0045] In the isolation matrix converter provided by the embodiment of the present application, the bidirectional switch module includes two controllable switching tubes, a first switching tube and a second switching tube, and two diodes, a first diode and a second diode, where the first switching tube and the first diode are connected in series to form a first bridge arm of the module, and the second switching tube and the second diode are connected in series to form a second bridge arm of the module. The first switching tube and the second switching tube are merely names of the switching tubes and do not specifically indicate their positions.

[0046] The embodiment of the present application does not specifically limit the positions of the two diodes, and for example, they may be located on two upper half bridge arms at the same time, or on two lower half bridge arms at the same time.

[0047] Please refer to FIG. 4, which is a schematic diagram of a bidirectional switch module provided by an embodiment of the present application.

[0048] 4, the two upper half bridge arms are controllable switching tubes, and the two lower half bridge arms are diodes. That is, Q1 and Q3 are both controllable switching tubes, D2 and D4 are both diodes, and Q1 includes an anti-parallel diode D1, and Q3 includes an anti-parallel diode D3. A clamp capacitor C1 is connected to both ends of the bridge arms of the module.

[0049] Please refer to FIG. 5, which is a schematic diagram of yet another bidirectional switch module provided by an embodiment of the present application.

[0050] 5, the two upper half bridge arms are diodes, and the two lower half bridge arms are controllable switching tubes. That is, Q12 and Q14 are both controllable switching tubes, D11 and D13 are both diodes, Q12 includes an anti-parallel diode D12, and Q14 includes an anti-parallel diode D14. A clamp capacitor C1 is connected to both ends of the bridge arms of the module.

[0051] 4 and 5 both show the case where two controllable switching tubes and two diodes are included, and hereinafter, the drawings will be combined to show the case where the bidirectional switch module includes three controllable switching tubes and one diode, i.e., the bidirectional switch module includes three controllable switching tubes, namely, the first switching tube, the second switching tube, and the third switching tube, and one diode, namely, the first diode, and the first switching tube and the second switching tube are connected in series to form the first bridge arm of the module, and the third switching tube and the first diode are connected in series to form the second bridge arm of the module.

[0052] Please refer to FIG. 6, which is a schematic diagram of another bidirectional switch module provided by an embodiment of the present application.

[0053] In Figure 6, the left bridge arm includes two controllable switching tubes Q1 and Q2, the upper half bridge arm on the right includes controllable switching tube Q3, and the lower half bridge arm on the right includes diode D4. The anti-parallel diode of Q1 is D1, the anti-parallel diode of Q2 is D2, and the anti-parallel diode of Q3 is D3. A clamp capacitor C1 is connected across both ends of the bridge arms of the module.

[0054] Please refer to FIG. 7, which is a schematic diagram of another bidirectional switch module provided by an embodiment of the present application.

[0055] In Figure 7, the left bridge arm includes two controllable switching tubes Q1 and Q2, the upper half bridge arm on the right includes diode D3, and the lower half bridge arm on the right includes controllable switching tube Q4. The anti-parallel diode of Q1 is D1, the anti-parallel diode of Q2 is D2, and the anti-parallel diode of Q4 is D4. A clamp capacitor C1 is connected across both ends of the bridge arms of the module.

[0056] 6 and 7 only illustrate the position of one diode, and the diode can be located in any of the four half-bridge arms. Figures 6 and 7 include three controllable switching tubes, ensuring that the voltage of each bidirectional switch module can be controlled. Specifically, the duty cycle of the controllable switching tubes can be adjusted to adjust the module voltage.

[0057] The secondary winding of the transformer is connected to a rectifier bridge, which includes at least one of a diode or a controllable switching tube.

[0058] When the rectifier bridge includes a diode, refer to FIG. 3, and the transformer in FIG. 3 has only one secondary winding. Below, we will introduce the case where the transformer includes multiple secondary windings.

[0059] The transformer includes multiple secondary windings, each connected to a corresponding rectifier bridge, and can accommodate multiple output ports, allowing for flexible voltage and power adjustment for each output port by adding a post-stage converter.

[0060] Please refer to FIG. 8, which is a schematic diagram of yet another isolated matrix converter provided by an embodiment of the present application.

[0061] 8, the transformer includes n secondary windings, where n is an integer greater than 1, and each winding is connected to a corresponding rectifier bridge. For example, the first rectifier bridge includes four diodes D5 to D8, and the output capacitor of the first rectifier bridge is Cbus1. The nth rectifier bridge includes four diodes Dn5 to Dn8, and the output capacitor of the nth rectifier bridge is Cbusn.

[0062] The isolated matrix converter shown in Figure 8 can be applied to electric vehicle charging scenarios, where each rectifier bridge corresponds to one charging gun to charge the electric vehicle. For example, the input voltage of the isolated matrix converter can be AC ​​10 kV or AC 35 kV.

[0063] The isolated matrix converters introduced above are all based on the example of a rectifier bridge including a diode. Below, we will introduce the case where the rectifier bridge includes a controllable switching tube.

[0064] Please refer to FIG. 9, which is a schematic diagram of another isolated matrix converter provided by an embodiment of the present application.

[0065] 9 includes four controllable switching tubes, namely Q5 to Q8, each of which includes a corresponding anti-parallel diode, namely D5 to D8, respectively. The output capacitor of the rectifier bridge is C1.

[0066] The isolated matrix converter shown in FIG. 9 is connected to the photovoltaic array on the right side, that is, the right side is the input end and the left side is the AC output end, realizing AC grid connection of photovoltaic power generation.

[0067] The embodiments of the present application do not specifically limit the application scenario of the isolated matrix converter, the number of bidirectional switch modules, the number of rectifier bridges, the type of switching tube in the rectifier bridges, or the type of switching tube in each bidirectional switch module. The various implementation methods introduced above can be freely combined.

[0068] The following describes in detail the working principle of the isolation matrix converter provided by the embodiment of the present application with reference to the accompanying drawings. The circuit of the isolation matrix converter is shown in Figure 3, taking the bidirectional switch module as an example, where all the controllable switching tubes are used.

[0069] Please refer to FIG. 10, which is an oscillogram of a three-phase AC voltage provided by an embodiment of the present application.

[0070] If the voltage waveform of a three-phase power grid is as shown in Figure 10, phases A, B, and C differ by 120 degrees, and from 0 to 30 degrees, the absolute value of phase A voltage is the largest, the absolute value of phase B is the smallest, and the absolute value of phase C is the second smallest. In addition, the phase A voltage is opposite to the phase B voltage and the phase C voltage. As shown in the circuit of Figure 3, Q2 and Q4 in the bidirectional switch module are the main switching tubes. When Q1 and Q3 are turned off, the switching timing of Q2 and Q4 tubes during normal operation is as shown in Figure 11.

[0071] Please refer to FIG. 11, which is a driving timing diagram of the bidirectional switch module of the isolated matrix converter provided by the embodiment of the present application.

[0072] When the isolated matrix converter is a three-phase isolated matrix converter, each phase of the three-phase isolated matrix converter includes at least one bidirectional switch module; The converter further includes a controller; When the three-phase voltages shown in Fig. 10 are combined, the absolute value of the A-phase voltage is the highest, the absolute value of the C-phase voltage is the second highest, and the absolute value of the B-phase voltage is the smallest. In Fig. 11, Qa2 indicates the drive timing of Q2 in A-phase, Qa4 indicates the drive timing of Q4 in A-phase, Qc2 indicates the drive timing of Q2 in C-phase, Qc4 indicates the drive timing of Q4 in C-phase, Qb2 indicates the drive timing of Q2 in B-phase, and Qb4 indicates the drive timing of Q4 in B-phase.

[0073] The controller further controls the switching tube that is not subjected to the voltage stress of the phase having the highest absolute value of the phase voltage to always be on, and the switching tube that is subjected to the voltage stress of the highest phase to operate at a preset duty ratio or a preset switching frequency, for example, a duty ratio of 50%.

[0074] The controller further controls the phase having the second highest absolute value of the phase voltage, so that the switching tube that is not subjected to voltage stress when the highest phase switching tube is turned on turns on before the highest phase bidirectional switch module turns off, and the switching tube that is subjected to voltage stress of the second highest phase turns on after the highest phase bidirectional switch module turns off, and both switches turn off simultaneously, and the Q4 duty ratio is the actual duty ratio of the unit, and this duty ratio is determined according to the relationship between the phase voltage value and the highest phase voltage.

[0075] The controller further controls the switching tube that is not subjected to voltage stress when the bidirectional switch module of the second-highest phase, which has the smallest absolute value of the phase voltage, turns on before the bidirectional switch module of the second-highest phase turns off, and the switching tube that is subjected to voltage stress turns on after the bidirectional switch module of the second-highest phase turns off, and both switches turn off simultaneously, and the Q2 duty ratio is the actual duty ratio of the unit, which is determined according to the relationship between the phase voltage value and the highest phase voltage value.

[0076] The specific locations of the above switching tubes in the bidirectional switch module can be determined according to the actual topology structure, and different bidirectional switch modules may show different switching tubes, for example, if the upper two half-bridge arms include controllable switching tubes, it is different from if the lower two half-bridge arms include controllable switching tubes. However, regardless of the structure of the bidirectional switch module, the above are divided into switching tubes that are subject to voltage stress and switching tubes that are not subject to voltage stress.

[0077] For ease of understanding, the absolute value of the phase voltage of the A phase is the highest in the range of 0 to 30 degrees shown in FIG. 10, and this will be taken as an example below.

[0078] The controller further controls the second switching tube Q2 of the phase with the highest absolute value of the phase voltage to be turned on, and the fourth switching tube Q4 of the highest phase to perform a switching operation at a preset duty ratio or a preset switching frequency, for example, the preset duty ratio is 50%; The fourth switching tube Q4 of the phase having the second highest absolute value of the phase voltage is turned on before the fourth switching tube Q4 of the highest phase is turned off, and the second switching tube Q2 of the phase having the second highest absolute value of the phase voltage is turned on after the fourth switching tube Q4 of the phase having the second highest absolute value is turned off; The second switching tube Q2 of the phase having the smallest absolute value of the phase voltage is controlled to turn on before the second switching tube Q2 and fourth switching tube Q4 of the second highest phase are turned off, and the fourth switching tube Q4 of the phase having the smallest absolute value of the phase voltage is controlled to turn on after the second switching tube Q2 and fourth switching tube Q4 of the second highest phase are turned off.

[0079] The above Q2 and Q4 indicate the second and fourth switching tubes in each phase, and the four switching tubes in each phase have the same numbers and are distinguished only by different phases.

[0080] When the converter includes at least two bidirectional switch modules connected in series, the controller specifically controls and operates the controllable switching tube in the bidirectional switch unit such that, when the voltage of the clamp capacitor is greater than a first preset voltage, the clamp capacitor is discharged until the voltage of the clamp capacitor is less than a second preset voltage, and the first preset voltage is greater than the second preset voltage, thereby balancing the voltages between the at least two bidirectional switch modules; When the converter includes at least two bidirectional switch modules connected in series, the controller specifically controls and operates the controllable switching tube in the bidirectional switch unit so that, when the voltage of the clamp capacitor is smaller than a third preset voltage, the clamp capacitor is charged until the voltage of the clamp capacitor is greater than a fourth preset voltage, thereby balancing the voltages between the at least two bidirectional switch modules, and the third preset voltage is smaller than the fourth preset voltage; The second preset voltage is greater than the third preset voltage.

[0081] For the converter provided by this embodiment, if the converter includes at least two bidirectional switch modules connected in series, the operation of the controllable switching tube in the bidirectional switch module can be controlled to charge or discharge the clamp capacitor, and the voltage on the clamp capacitor can be changed to achieve voltage balance among the multiple series-connected bidirectional switch modules. When the voltages are balanced, the voltage stresses on the switching tubes in the multiple bidirectional switch modules are equal, so that the switching tubes in some bidirectional switch modules do not experience large voltage stresses and the switching tubes in other bidirectional switch modules do not experience small voltage stresses, thereby better protecting the switching tubes.

[0082] Please refer to FIGS. 12A to 12D, which are diagrams illustrating the operation principle of the switching operation in the bidirectional switch module provided by the embodiment of the present application.

[0083] As shown in Figures 12A to 12D, when the A-phase switching tube Q4 is turned off between 0 and 30 degrees, the clamp capacitor C1 operates as follows: when Q4 is turned off, the parasitic inductor in the loop may generate a high voltage spike at Q4; however, due to the presence of C1, the voltage spike is limited to the voltage of C1; that is, C1 clamps the spike voltage and effectively suppresses the voltage spike.

[0084] To ensure that C1 effectively protects the controllable switching tube, the voltage across C1 must be controlled within a reasonable range. For example, the normal voltage is set to V0. When the voltage is higher than the first preset voltage V1, the module enters overvoltage discharge mode. When the voltage is lower than the second preset voltage V2, the module exits overvoltage discharge mode. When the voltage is lower than the third preset voltage V3, the module enters low-voltage charging mode. When the voltage is higher than the fourth preset voltage V4, the module exits low-voltage charging mode. The following describes the charge / discharge mode operation of clamp capacitor C1 when phase A is at its maximum (0-30°), intermediate (30-60°), and minimum (60-90°) temperatures.

[0085] Between 0 and 30 degrees, when the voltage across the clamp capacitor C1 of the bidirectional switch module for phase A is lower than V2, the module enters bus undervoltage charging mode. In this mode, the long-pass tube Q2 of the module is turned off and the module does not start up Q4 when it should be turned on. The main power loop current charges C1. If the voltage across C1 of the module is higher than V4, Q2 continues to enter the long-pass state in the next switching period, and Q4 switches according to the configured logic. If the voltage across the absorbing clamp capacitor C1 of the module is higher than V1, the module enters bus overvoltage discharge mode. In this mode, the long-pass tube Q2 of the module is turned off and Q1 is shut down when Q4 is turned on, and the loop current charges C1. If each phase bridge arm contains multiple bidirectional switch modules connected in series, when Q4 turns off, Q1 is turned off and Q2 is turned on simultaneously to reduce voltage stress on the other modules in phase A. It continues discharging in the next switching period, and when the voltage across C1 becomes lower than V2, it exits the discharging mode.

[0086] Between 30 and 60 degrees, if the voltage of the clamp capacitor C1 of the A-phase bidirectional switch module is lower than V3, the module enters bus undervoltage charging mode. During normal operation, Q2 of the module turns on for a certain period before Q4 turns off in preparation for Q4's zero-voltage turn-on. However, in charging mode, Q2 will not turn on, and Q4 will not turn on within this period, allowing the loop current to charge C1. If charging is not completed within this period, it will continue until charging is completed in the next switching period. If the voltage of the absorption clamp capacitor C1 of the module is higher than V1, the module enters bus overvoltage discharge mode, preventing Q2 from starting up. If Q4 needs to start up normally, Q1 will start up when Q4 starts up, allowing the main loop current to discharge C1. However, before the current reverses, capacitor Cx must be discharged.

[0087] Between 60 and 90 degrees, when the voltage of the clamp capacitor C1 of the A-phase bidirectional switch module is lower than V3, the module enters bus undervoltage charging mode. Normally, Q4 turns on before Q2 and Q4 of the middle phase C turn on, creating a zero-voltage turn-on condition for Q2. In charging mode, Q4 and Q2 do not start up together within a cycle. When the voltage of the absorbing clamp capacitor C1 of the module is higher than V1, the module enters bus overvoltage discharging mode. Q4 turns on normally, but when Q2 turns on normally, Q1 turns on instead of Q2. When Q2 and Q4 should turn off normally, Q1 and Q4 turn off, thereby discharging to C1.

[0088] Below, we will specifically explain how C1 suppresses voltage spikes when Q4 is turned off.

[0089] In FIG. 12A, the A-phase current enters from Q4, flows through Q2 and D2, and flows out from the upper end of Q2, and in this case, both Q1 and Q3 are turned off.

[0090] 12B, Q4 turns off, Q1 and Q3 remain off, and current charges the junction capacitor Co4 of Q4 and discharges the junction capacitor Co3 of Q3.

[0091] In FIG. 12C, Q4 turns off, Q1 and Q3 remain off, and the voltage formed by the current in the junction capacitor Co4 of Q4 reaches the voltage across the clamp capacitor C1. In this case, Co3 discharges to 0, and then D3 turns on to suppress the spike in the voltage of Q4 and protect the safety of Q4.

[0092] In FIG. 12D, the current flows through the parasitic inductance of the loop (meaning the large loop of the entire isolation matrix converter), and after D3, C1, and D2 resonate to 0, the current flows in the opposite direction to charge and discharge the junction capacitors (Co3 and Co4) of Q3 and Q4, until the total voltage of Q4 in all the series-connected bidirectional switch modules reaches the line voltage of the AC input, causing the voltage across Q4 to decrease and the voltage across Q3 to increase.

[0093] Without C1, the voltages of Co3 and Co4 would be large, which would require Q3 and Q4 to be subjected to high voltage stress, causing damage if the withstand voltage is exceeded.

[0094] In order to more clearly understand the effect of the clamp capacitor of the bidirectional switch module in the isolation matrix converter provided by the present application in suppressing spike voltages during switching tube operation, the following will be presented in detail with oscillograms.

[0095] Please refer to FIG. 13, which is a voltage stress diagram of the turn-off process of Q4 provided by an embodiment of the present application.

[0096] 13, due to the presence of the clamp capacitor C1, a voltage stress level H exists when Q4 is turned off, i.e., the voltage is clamped. Without the clamp capacitor C1, a high spike voltage would appear during the turn-off process of Q4, which could affect Q4, for example, exceeding the withstand voltage of Q4 and potentially damaging it. Using the same principle, other switching tubes can be protected by C1 from being affected by the spike voltage during the switching process.

[0097] The above embodiment is introduced by taking the A phase as an example, and the operation processes of the switching tubes of other phases and different phase sections are similar, and therefore will not be described in detail here.

[0098] If the switching tubes in the bidirectional switch modules are of a non-fully controlled type (ie, including a combination of a controllable switching tube and a diode), the charge / discharge mode of each bidirectional switch module is controlled only in a specific phase section.

[0099] In all of the solutions described above, Q2 and Q4 in the bidirectional switch module are described as the main switches. In actual use, Q1 and Q3 may be used as the main switches, and Q2 and Q4 may be used as voltage adjusting switching tubes for clamping capacitor C1. The relevant timings need to be adjusted accordingly, and no further explanation is given here.

[0100] The isolated matrix converter provided by the embodiment of the present application includes a clamp capacitor in the bidirectional switch module, which can suppress spike voltages in the switching tube during switching, thereby protecting the switching tube and further ensuring the safety and reliability of the entire converter. In addition, controlling the charge and discharge modes of the clamp capacitor can better control the voltage stress of the converter.

[0101] In addition, in the isolation matrix converter provided by the embodiments of the present application, each phase may include multiple bidirectional switch modules connected in series. In this way, when the voltage of the bridge arm is high, the voltage received by each bidirectional switch module can be reduced, which further contributes to the selection of the type of controllable switching tube in the bidirectional switch module and reduces the cost of the converter.

[0102] The bidirectional switch module in the above embodiment is presented in the form of a bridge arm, i.e., a two-level topology is presented as an example, but it may also be designed as a three-level full-bridge or multi-level topology such as I-NPC or A-NPC.

[0103] Method Example Based on the isolated matrix converter provided by the above embodiment, the embodiment of the present application further provides a control method for the isolated matrix converter, which will be described in detail below in conjunction with the accompanying drawings.

[0104] Please refer to FIG. 14, which is a flowchart of a control method for an isolated matrix converter provided by an embodiment of the present application.

[0105] Regarding the control method for the isolated matrix converter provided by this embodiment, the isolated matrix converter includes a bidirectional switch module, a transformer, a resonant inductor, a resonant capacitor, and a bridge arm capacitor, the bidirectional switch module is connected in series with the bridge arm capacitor to form a bridge arm of the converter, each bridge arm of the converter includes at least one bidirectional switch module, and the primary winding of the transformer is connected in series with the resonant inductor and the resonant capacitor and then connected to both ends of the bridge arm of the converter, the bidirectional switch module includes a clamp capacitor and a bidirectional switch unit, the bidirectional switch unit forms two bridge arms of the module, and both ends of the clamp capacitor are connected to both ends of the two bridge arms of the module, the clamp capacitor forms a clamp absorption circuit with two upper bridge arms or two lower bridge arms of the two bridge arms, and the bidirectional switch unit includes at least two controllable switching tubes, The method comprises: S1401: controlling and operating a switching tube in a bidirectional switch unit; S1402: Controlling the clamp capacitor to suppress voltage spikes occurring during the operation of the switching tube.

[0106] In the control method for an isolated matrix converter provided by the embodiment of the present application, a clamp capacitor is included in the bidirectional switch module. The clamp capacitor can be used to suppress spike voltages in the switching tube during the switching process, thereby protecting the switching tube and further ensuring the safety and reliability of the entire converter.

[0107] When the bidirectional switch module includes two controllable switching tubes, the two controllable switching tubes are located in the same two upper bridge arms or the same two lower bridge arms.

[0108] The bidirectional switch module includes four controllable switching tubes, namely, a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube; a first end of the first switching tube and a first end of the third switching tube are both connected to a first end of the clamp capacitor, a second end of the second switching tube and a second end of the fourth switching tube are both connected to a second end of the clamp capacitor, a second end of the first switching tube is connected to a first end of the second switching tube, and a second end of the third switching tube is connected to a first end of the fourth switching tube; The common end of the first switching tube and the second switching tube is the first end of the bidirectional switch module, and the common end of the third switching tube and the fourth switching tube is the second end of the bidirectional switch module.

[0109] The method provided by this embodiment includes, when the converter includes at least two bidirectional switch modules connected in series, The method further includes a step of balancing the voltages between the at least two bidirectional switch modules by controlling and operating the controllable switching tubes in the bidirectional switch unit such that, when the voltage of the clamp capacitor is greater than a first preset voltage, the clamp capacitor is discharged until the voltage of the clamp capacitor is less than a second preset voltage; and when the first preset voltage is greater than the second preset voltage and the switching tubes are controlled and operated such that the clamp capacitor is discharged, the bidirectional switch module must include at least three switching tubes.

[0110] The method provided by this embodiment includes, when the converter includes at least two bidirectional switch modules connected in series, Further comprising: when the voltage of the clamp capacitor is smaller than a third preset voltage, controlling and operating the controllable switching tube in the bidirectional switch unit to charge the clamp capacitor until the voltage of the clamp capacitor is larger than a fourth preset voltage, thereby balancing the voltage between the at least two bidirectional switch modules, wherein the third preset voltage is smaller than the fourth preset voltage; The second preset voltage is greater than the third preset voltage.

[0111] Regarding the method provided by this embodiment, when the converter includes at least two bidirectional switch modules connected in series, the operation of the controllable switching tube in the bidirectional switch module can be controlled to charge or discharge the clamp capacitor, and the voltage on the clamp capacitor can be changed to achieve voltage balance among the multiple series-connected bidirectional switch modules. When the voltages are balanced, the voltage stresses on the switching tubes in the multiple bidirectional switch modules are equal, so that the switching tubes in some bidirectional switch modules do not experience large voltage stresses and the switching tubes in other bidirectional switch modules do not experience small voltage stresses, thereby better protecting the switching tubes.

[0112] When the isolated matrix converter is a three-phase isolated matrix converter, each phase of the three-phase isolated matrix converter includes at least one bidirectional switch module; The method comprises: controlling the switching tube that is not subjected to the voltage stress of the phase having the highest absolute value of the phase voltage to always be on, and the switching tube that is subjected to the voltage stress of the highest phase to perform a switching operation at a preset duty ratio; Controlling the phase having the second highest absolute value of phase voltage so that the switching tube that is not subjected to voltage stress when the highest phase switching tube is turned on is turned on before the highest phase bidirectional switch module is turned off, and the switching tube that is subjected to voltage stress of the second highest phase is turned on after the highest phase bidirectional switch module is turned off; The method further includes a step of controlling the switching tube that is not subjected to voltage stress when the bidirectional switch module of the second highest phase, which is the phase having the smallest absolute value of the phase voltage, is turned on so that it turns on before the bidirectional switch module of the second highest phase is turned off, and the switching tube that is subjected to voltage stress turns on after the bidirectional switch module of the second highest phase is turned off.

[0113] The above description of the disclosed embodiments will enable one skilled in the art to make or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An isolation matrix converter, comprising: a bidirectional switch module, a transformer, a resonant inductor, a resonant capacitor, and a bridge arm capacitor; the bidirectional switch module is connected in series with the bridge arm capacitor to form a bridge arm of the converter, and each bridge arm of the converter includes at least one bidirectional switch module; a primary winding of the transformer is connected in series with the resonant inductor and the resonant capacitor, and then connected to both ends of a bridge arm of the converter; The bidirectional switch module includes a clamp capacitor and a bidirectional switch unit, the bidirectional switch unit forms two bridge arms of the module, both ends of the clamp capacitor are connected to both ends of the two bridge arms of the module, the clamp capacitor forms a clamp absorption circuit with two upper bridge arms or two lower bridge arms of the two bridge arms, and the bidirectional switch unit includes at least two controllable switching tubes; The clamp capacitor is used to suppress voltage spikes that occur when a switching tube in the bidirectional switch module operates. A converter characterized by:

2. Two of the at least two controllable switching tubes included in the bidirectional switch module are located in the same two upper bridge arms or the same two lower bridge arms; 2. The converter according to claim 1 .

3. The bidirectional switch module includes four controllable switching tubes, namely, a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube; a first end of the first switching tube and a first end of the third switching tube are both connected to a first end of the clamp capacitor, a second end of the second switching tube and a second end of the fourth switching tube are both connected to a second end of the clamp capacitor, a second end of the first switching tube is connected to the first end of the second switching tube, and a second end of the third switching tube is connected to the first end of the fourth switching tube; a common end of the first switching tube and the second switching tube is a first end of the bidirectional switch module, and a common end of the third switching tube and the fourth switching tube is a second end of the bidirectional switch module; 3. The converter according to claim 2.

4. The bidirectional switch module includes three controllable switching tubes, namely, a first switching tube, a second switching tube, and a third switching tube, and one diode, namely, a first diode; the first switching tube and the second switching tube are connected in series to form a first bridge arm of the module, and the third switching tube and the first diode are connected in series to form a second bridge arm of the module.

3. The converter according to claim 2.

5. The bidirectional switch module includes two controllable switching tubes, a first switching tube and a second switching tube, and two diodes, a first diode and a second diode; the first switching tube and the first diode are connected in series to form a first bridge arm of the module, and the second switching tube and the second diode are connected in series to form a second bridge arm of the module.

3. The converter according to claim 2.

6. the converter includes at least two bidirectional switch modules connected in series; The converter further includes a controller, and the controller specifically controls and operates a controllable switching tube in the bidirectional switch unit to discharge the clamp capacitor until the voltage of the clamp capacitor is smaller than a second preset voltage when the voltage of the clamp capacitor is larger than a first preset voltage, thereby balancing the voltage between the at least two bidirectional switch modules, and the first preset voltage is larger than the second preset voltage.

5. The converter according to claim 1, wherein the first and second electrodes are electrically connected to each other.

7. the converter includes at least two bidirectional switch modules connected in series; The converter further includes a controller, and the controller specifically controls and operates a controllable switching tube in the bidirectional switch unit to charge the clamp capacitor until the voltage of the clamp capacitor is greater than a fourth preset voltage when the voltage of the clamp capacitor is less than a third preset voltage, thereby balancing the voltages between the at least two bidirectional switch modules; the third preset voltage is less than the fourth preset voltage; 6. The converter according to claim 1, wherein the first and second electrodes are electrically connected to each other.

8. the isolated matrix converter is a three-phase isolated matrix converter, and each phase of the three-phase isolated matrix converter includes at least one of the bidirectional switch modules; The converter further includes a controller, and the controller further controls the switching tube that is not subjected to a voltage stress of a phase having the highest absolute value of a phase voltage to always be turned on, and the switching tube that is subjected to the voltage stress of the highest phase to perform a switching operation at a preset duty ratio; The controller further controls the switching tube of the phase having the second highest absolute value of the phase voltage, which is not subjected to voltage stress when the switching tube of the highest phase is turned on, to turn on before the bidirectional switch module of the highest phase is turned off, and the switching tube of the phase having the second highest absolute value of the phase voltage is turned on after the bidirectional switch module of the highest phase is turned off; The controller further controls the switching tube that is not subjected to voltage stress when the bidirectional switch module of the second highest phase, which is the phase having the smallest absolute value of the phase voltage, is turned on so that it turns on before the bidirectional switch module of the second highest phase is turned off, and the switching tube that is subjected to voltage stress turns on after the bidirectional switch module of the second highest phase is turned off.

6. The converter according to claim 2, wherein the first and second electrodes are electrically connected to the first and second electrodes.

9. When each bridge arm of the converter includes a plurality of the bidirectional switch units, the plurality of bidirectional switch units are connected in series.

6. The converter according to claim 1, wherein the first and second electrodes are electrically connected to each other.

10. a secondary winding of the transformer connected to a rectifier bridge, the rectifier bridge including at least one of a diode or a controllable switching tube; 6. The converter according to claim 1, wherein the first and second electrodes are electrically connected to each other.

11. The transformer includes a plurality of secondary windings, each secondary winding being connected to a corresponding rectifier bridge.

10. The converter of claim 9.

12. a control method for an isolation matrix converter, the isolation matrix converter including a bidirectional switch module, a transformer, a resonant inductor, a resonant capacitor, and a bridge arm capacitor, the bidirectional switch module being connected in series with the bridge arm capacitor to form a bridge arm of the converter, each bridge arm of the converter including at least one bidirectional switch module, a primary winding of the transformer being connected in series with the resonant inductor and the resonant capacitor and then connected to both ends of the bridge arm of the converter, the bidirectional switch module including a clamp capacitor and a bidirectional switch unit, the bidirectional switch unit forming two bridge arms of the module, both ends of the clamp capacitor being connected to both ends of the two bridge arms of the module, the clamp capacitor forming a clamp absorption circuit with two upper bridge arms or two lower bridge arms of the two bridge arms, the bidirectional switch unit including at least two controllable switching tubes; The method comprises: and controlling and operating a switching tube in the bidirectional switch module to charge or discharge the clamp capacitor to change the voltage of the clamp capacitor, the clamp capacitor being used to limit a voltage spike generated when the switching tube in the bidirectional switch module operates to the voltage of the clamp capacitor. A control method comprising:

13. Two of the at least two controllable switching tubes included in the bidirectional switch module are located in the same two upper bridge arms or the same two lower bridge arms; 13. The control method according to claim 12.

14. The bidirectional switch module includes four controllable switching tubes, namely, a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube; a first end of the first switching tube and a first end of the third switching tube are both connected to a first end of the clamp capacitor, a second end of the second switching tube and a second end of the fourth switching tube are both connected to a second end of the clamp capacitor, a second end of the first switching tube is connected to the first end of the second switching tube, and a second end of the third switching tube is connected to the first end of the fourth switching tube; a common end of the first switching tube and the second switching tube is a first end of the bidirectional switch module, and a common end of the third switching tube and the fourth switching tube is a second end of the bidirectional switch module; 14. The control method according to claim 13.

15. the converter includes at least two bidirectional switch modules connected in series; When the voltage of the clamp capacitor is greater than a first preset voltage, controlling and operating a controllable switching tube in the bidirectional switch unit to discharge the clamp capacitor until the voltage of the clamp capacitor is less than a second preset voltage, thereby balancing the voltage between the at least two bidirectional switch modules, wherein the first preset voltage is greater than the second preset voltage; The control method according to any one of claims 12 to 13.

16. the converter includes at least two bidirectional switch modules connected in series; When the voltage of the clamp capacitor is smaller than a third preset voltage, controlling and operating a controllable switching tube in the bidirectional switch unit to charge the clamp capacitor until the voltage of the clamp capacitor is greater than a fourth preset voltage, thereby balancing the voltage between the at least two bidirectional switch modules; the third preset voltage is less than the fourth preset voltage; 15. The control method according to claim 13 or 14.

17. the isolated matrix converter is a three-phase isolated matrix converter, and each phase of the three-phase isolated matrix converter includes at least one of the bidirectional switch modules; The method comprises: controlling the switching tube that is not subjected to the voltage stress of the phase having the highest absolute value of the phase voltage to always be on, and the switching tube that is subjected to the voltage stress of the highest phase to perform a switching operation at a preset duty ratio; controlling the switching tube of the phase having the second highest absolute value of the phase voltage, which is not subjected to voltage stress when the switching tube of the highest phase is turned on, to turn on before the bidirectional switch module of the highest phase is turned off, and the switching tube of the phase having the second highest absolute value of the phase voltage, which is subjected to voltage stress, to turn on after the bidirectional switch module of the highest phase is turned off; controlling the switching tube that is not subjected to voltage stress when the bidirectional switch module of the second highest phase, which is the phase having the smallest absolute value of the phase voltage, is turned on before the bidirectional switch module of the second highest phase is turned off, and the switching tube that is subjected to voltage stress is turned on after the bidirectional switch module of the second highest phase is turned off, 14. The control method according to claim 13.

Images