Power module and charging device

Abstract

Provided in the present application are a power module and a charging device. The power module comprises N staggered parallel PFC circuits and a controller. Each of the staggered parallel PFC circuits comprises a PFC inductor, an autotransformer, a first rectifier bridge arm and a second rectifier bridge arm, wherein the autotransformer comprises a first winding and a second winding coupled to each other, one end of the PFC inductor is used for receiving an alternating current and the other end of the PFC inductor is used for connecting to one end of the first winding and one end of the second winding, the other end of the first winding is used for connecting to the first rectifier bridge arm, and the other end of the second winding is used for connecting to the second rectifier bridge arm. The controller is used for: in response to the absolute value of the difference value between the current of the first winding and the current of the second winding being greater than or equal to a preset value, adjusting the duty ratio of a driving signal of a switching transistor of the first rectifier bridge arm or a switching transistor of the second rectifier bridge arm in a next switching period.

Description

Power modules and charging equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on June 5, 2023, with application number 202310661298.X and application name “Power Module and Charging Device,” the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of new energy technology, and in particular to a power module and a charging device. Background Art

[0004] High-power AC-DC power modules typically utilize interleaved parallel power factor correction (PFC) circuits to achieve high power output. To achieve good current sharing in the PFC circuit, an autotransformer is typically incorporated into the circuit topology. However, due to variations in switching device parameters, switch drive delays, and dead time, the volt-second product of the autotransformer can exceed the allowable value of the core, leading to core saturation and, in turn, failure of the switching devices in the circuit.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a power module and a charging device that can dynamically adjust the excitation current in an autotransformer, thereby solving the problem of core saturation of the autotransformer and protecting devices in the circuit from failure due to core saturation of the autotransformer.

[0007] In a first aspect, an embodiment of the present application provides an AC-DC power module comprising N groups of interleaved parallel PFC circuits and a controller. Each group of interleaved parallel PFC circuits is configured to convert one phase of AC power from an AC power source into DC power and output it to a DC bus, where 1≤N≤3 and N is an integer. Each group of interleaved parallel PFC circuits comprises a PFC inductor, an autotransformer, a first rectifier bridge arm, and a second rectifier bridge arm. The autotransformer comprises a first winding and a second winding coupled to each other. One end of the PFC inductor is configured to receive AC power, and the other end of the PFC inductor is configured to connect one end of the first winding and one end of the second winding. The other end of the first winding is configured to connect to the first rectifier bridge arm, and the other end of the second winding is configured to connect to the second rectifier bridge arm.

[0008] The controller is configured to adjust a duty cycle of a drive signal for a switch of the first rectifier bridge arm or the second rectifier bridge arm in a next switching cycle in response to an absolute value of a difference between a current of the first winding and a current of the second winding being greater than or equal to a preset value. The operating frequency of the switch is greater than the frequency of the alternating current.

[0009] The preset value is the current intensity when the magnetic core of the autotransformer reaches magnetic saturation, that is, the saturation current of the autotransformer.

[0010] When N=1, the AC-DC power module includes a set of interleaved parallel PFC circuits, and one end of the PFC inductor is used to receive single-phase AC power.

[0011] When N=2, the AC-DC power module includes two sets of interleaved parallel PFC circuits, one end of the PFC inductor of each set of interleaved parallel PFC circuits is used to receive one phase of the three-phase AC power, and the PFC inductors of the two sets of interleaved parallel PFC circuits are used to receive AC power of different phases.

[0012] When N=3, the AC-DC power module includes three groups of interleaved parallel PFC circuits, one end of the PFC inductor of each group of interleaved parallel PFC circuits is used to receive one phase of the three-phase AC power, and the PFC inductors of the three groups of interleaved parallel PFC circuits are used to receive AC power of different phases.

[0013] Based on this setting, not only can the problem of damage to the switching devices in the circuit due to saturation of the autotransformer's core be solved, but the controller only starts to adjust the duty cycle of the driving signal of the switching tube when the difference between the currents of the two windings reaches a preset value, thereby simplifying the control strategy of the controller.

[0014] In one possible embodiment, the controller is used to: in response to the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the first winding current being greater than the absolute value of the second winding current, reduce the duty cycle of the drive signal of the switching tube of the first rectifier bridge arm in the next switching cycle.

[0015] Based on this setting, the excitation current of the first winding can be reduced. If, in the next switching cycle, the absolute value of the difference between the current of the first winding and the current of the second winding is still greater than or equal to the preset value, and the absolute value of the current of the first winding is greater than the absolute value of the current of the second winding, the controller will continue to reduce the duty cycle of the drive signal of the switch tube of the first rectifier bridge arm in the next switching cycle until the absolute value of the difference between the current of the first winding and the current of the second winding is less than the preset value. This can prevent the magnetic core of the autotransformer from saturating, thereby preventing the switching devices in the circuit from being damaged due to the saturation of the magnetic core of the autotransformer, thereby improving the operating reliability of the circuit.

[0016] In one possible embodiment, the controller is used to: in response to the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the second winding current being greater than the absolute value of the first winding current, reduce the duty cycle of the drive signal of the switching tube of the second rectifier bridge arm in the next switching cycle.

[0017] Based on this setting, the excitation current of the second winding can be reduced. If, in the next switching cycle, the absolute value of the difference between the current of the first winding and the current of the second winding is still greater than or equal to the preset value, and the absolute value of the current of the second winding is greater than the absolute value of the current of the first winding, the controller will continue to reduce the duty cycle of the drive signal of the switch tube of the second rectifier bridge arm in the next switching cycle until the absolute value of the difference between the current of the first winding and the current of the second winding is less than the preset value. This can prevent the magnetic core of the autotransformer from saturating, so that the switching devices in the circuit will not be damaged due to the saturation of the magnetic core of the autotransformer, thereby improving the operating reliability of the circuit.

[0018] In one possible implementation, each interleaved parallel PFC circuit includes bus capacitors, where the bus capacitors include a positive bus capacitor and a negative bus capacitor connected in series. One end of the positive bus capacitor is connected to the positive DC bus, and the other end of the negative bus capacitor is connected to the negative DC bus.

[0019] The first rectifier bridge arm includes a first diode, a second diode, a third diode, a fourth diode, a first switching tube, and a second switching tube. The first, second, third, and fourth diodes are connected in series, with the cathode of the first diode connected to the positive DC bus and the anode of the fourth diode connected to the negative DC bus. One end of the first switching tube is connected to the midpoint of the series connection of the first and second diodes, and the other end of the first switching tube is connected to the midpoint of the bus capacitor. One end of the second switching tube is connected to the midpoint of the series connection of the third and fourth diodes, and the other end of the second switching tube is connected to the midpoint of the bus capacitor.

[0020] The second rectifier bridge arm includes a fifth diode, a sixth diode, a seventh diode, an eighth diode, a third switch tube, and a fourth switch tube. The fifth diode, the sixth diode, the seventh diode, and the eighth diode are connected in series, the cathode of the fifth diode is connected to the positive DC bus, and the anode of the eighth diode is connected to the negative DC bus. One end of the third switch tube is connected to the midpoint of the series connection of the fifth and sixth diodes, and the other end of the third switch tube is connected to the midpoint of the bus capacitor. One end of the fourth switch tube is connected to the midpoint of the series connection of the seventh and eighth diodes, and the other end of the fourth switch tube is connected to the midpoint of the bus capacitor.

[0021] In one possible embodiment, the controller is used to: reduce the duty cycle of the drive signal of the first switching tube in the next switching cycle in response to the phase voltage of the alternating current being in the positive half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being greater than the absolute value of the current of the second winding.

[0022] Based on this configuration, the excitation current of the first winding can be reduced. If, during the next switching cycle, the absolute value of the difference between the current of the first winding and the current of the second winding is still greater than or equal to the preset value, and the absolute value of the current of the first winding is greater than the absolute value of the current of the second winding, the controller will continue to reduce the duty cycle of the drive signal of the first switching tube in the next switching cycle until the absolute value of the difference between the current of the first winding and the current of the second winding is less than the preset value. This prevents the magnetic core of the autotransformer from saturating, thereby preventing damage to the switching devices in the circuit due to the saturation of the magnetic core of the autotransformer, and improving the operating reliability of the circuit.

[0023] In one possible embodiment, the controller is used to: reduce the duty cycle of the drive signal of the third switching tube in the next switching cycle in response to the phase voltage of the alternating current being in the positive half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being less than the absolute value of the current of the second winding.

[0024] Based on this configuration, the excitation current of the second winding can be reduced. If, during the next switching cycle, the absolute value of the difference between the current of the first winding and the current of the second winding is still greater than or equal to the preset value, and the absolute value of the current of the first winding is less than the absolute value of the current of the second winding, the controller will continue to reduce the duty cycle of the drive signal of the third switch tube in the next switching cycle until the absolute value of the difference between the current of the first winding and the current of the second winding is less than the preset value. This prevents the magnetic core of the autotransformer from saturating, thereby preventing damage to the switching devices in the circuit due to saturation of the magnetic core of the autotransformer, and improving the operating reliability of the circuit.

[0025] In one possible embodiment, the controller is used to: reduce the duty cycle of the drive signal of the second switching tube in the next switching cycle in response to the phase voltage of the alternating current being in the negative half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being greater than the absolute value of the current of the second winding.

[0026] Based on this configuration, the excitation current of the first winding can be reduced. If, during the next switching cycle, the absolute value of the difference between the current of the first winding and the current of the second winding is still greater than or equal to the preset value, and the absolute value of the current of the first winding is greater than the absolute value of the current of the second winding, the controller will continue to reduce the duty cycle of the drive signal of the second switching tube in the next switching cycle until the absolute value of the difference between the current of the first winding and the current of the second winding is less than the preset value. This prevents the magnetic core of the autotransformer from saturating, thereby preventing damage to the switching devices in the circuit due to the saturation of the magnetic core of the autotransformer, and improving the operating reliability of the circuit.

[0027] In one possible embodiment, the controller is used to: reduce the duty cycle of the drive signal of the fourth switching tube in the next switching cycle in response to the phase voltage of the alternating current being in the negative half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being less than the absolute value of the current of the second winding.

[0028] Based on this configuration, the excitation current of the second winding can be reduced. If, during the next switching cycle, the absolute value of the difference between the current of the first winding and the current of the second winding is still greater than or equal to the preset value, and the absolute value of the current of the first winding is less than the absolute value of the current of the second winding, the controller will continue to reduce the duty cycle of the drive signal of the fourth switch tube in the next switching cycle until the absolute value of the difference between the current of the first winding and the current of the second winding is less than the preset value. This prevents the magnetic core of the autotransformer from saturating, thereby preventing damage to the switching devices in the circuit due to saturation of the magnetic core of the autotransformer, and improving the operating reliability of the circuit.

[0029] In one possible embodiment, the first rectifier bridge arm includes a first diode, a second diode, and a first bidirectional switch tube. The first diode and the second diode are connected in series, the cathode of the first diode is connected to the positive DC bus, and the anode of the second diode is connected to the negative DC bus. One end of the first bidirectional switch tube is connected to the midpoint of the series connection of the first diode and the second diode, and the other end of the first bidirectional switch tube is connected to the midpoint of the bus capacitor. The second rectifier bridge arm includes a third diode, a fourth diode, and a second bidirectional switch tube. The third diode and the fourth diode are connected in series, the cathode of the third diode is connected to the positive DC bus, and the anode of the fourth diode is connected to the negative DC bus. One end of the second bidirectional switch tube is connected to the midpoint of the series connection of the third diode and the fourth diode, and the other end of the second bidirectional switch tube is connected to the midpoint of the bus capacitor.

[0030] In one possible embodiment, the controller is used to: in response to the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being greater than the absolute value of the current of the second winding, reduce the duty cycle of the drive signal of the first bidirectional switch tube in the next switching cycle.

[0031] Based on this configuration, the excitation current of the first winding can be reduced. If, during the next switching cycle, the absolute value of the difference between the current of the first winding and the current of the second winding is still greater than or equal to the preset value, and the absolute value of the current of the first winding is greater than the absolute value of the current of the second winding, the controller will continue to reduce the duty cycle of the drive signal of the first bidirectional switch in the next switching cycle until the absolute value of the difference between the current of the first winding and the current of the second winding is less than the preset value. This prevents the magnetic core of the autotransformer from saturating, thereby preventing damage to the switching devices in the circuit due to the saturation of the magnetic core of the autotransformer and improving the operational reliability of the circuit.

[0032] In one possible embodiment, the controller is used to: reduce the duty cycle of the drive signal of the second bidirectional switch tube in the next switching cycle in response to the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being less than the absolute value of the current of the second winding.

[0033] Based on this configuration, the excitation current of the second winding can be reduced. If, during the next switching cycle, the absolute value of the difference between the current of the first winding and the current of the second winding is still greater than or equal to the preset value, and the absolute value of the current of the first winding is less than the absolute value of the current of the second winding, the controller will continue to reduce the duty cycle of the drive signal of the second bidirectional switch in the next switching cycle until the absolute value of the difference between the current of the first winding and the current of the second winding is less than the preset value. This prevents the core of the autotransformer from saturating, thereby preventing damage to the switching devices in the circuit due to saturation of the core of the autotransformer and improving the operational reliability of the circuit.

[0034] In one possible embodiment, the first rectifier bridge arm includes a first and a second switching tube connected in series, with one end of the first switching tube connected to the positive DC bus and one end of the second switching tube connected to the negative DC bus. The second rectifier bridge arm includes a third and a fourth switching tube connected in series, with one end of the third switching tube connected to the positive DC bus and one end of the fourth switching tube connected to the negative DC bus. The other end of the first winding is connected to the midpoint of the series connection of the first and second switching tubes, and the other end of the second winding is connected to the midpoint of the series connection of the third and fourth switching tubes.

[0035] In one possible embodiment, the controller is used to: in response to the phase voltage of the alternating current being in the positive half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being greater than the absolute value of the current of the second winding, reduce the duty cycle of the drive signal of the second switching tube in the next switching cycle.

[0036] In one possible embodiment, the controller is used to: in response to the phase voltage of the alternating current being in the positive half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being less than the absolute value of the current of the second winding, reduce the duty cycle of the drive signal of the fourth switching tube in the next switching cycle.

[0037] In one possible embodiment, the controller is used to: reduce the duty cycle of the drive signal of the first switching tube in the next switching cycle in response to the phase voltage of the alternating current being in the negative half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being greater than the absolute value of the current of the second winding.

[0038] In one possible embodiment, the controller is used to: reduce the duty cycle of the drive signal of the third switching tube in the next switching cycle in response to the phase voltage of the alternating current being in the negative half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being less than the absolute value of the current of the second winding.

[0039] Based on this setting, the controller can adjust the excitation current of the first winding and the excitation current of the second winding of the autotransformer in real time, so that the magnetic core of the autotransformer is not saturated, so that the switching devices in the circuit will not be damaged due to the saturation of the magnetic core of the autotransformer, thereby improving the working reliability of the circuit.

[0040] In a second aspect, embodiments of the present application provide a charging device. The charging device includes at least one AC-DC power module as provided in the first aspect and any one of the possible implementations of the first aspect, a power distribution unit, and at least one charging interface. The input end of the AC-DC power module is used to receive alternating current (AC), the output end of the AC-DC power module is connected to the input end of the power distribution unit, the output end of the power distribution unit is connected to the input end of the charging interface, and the output end of the charging interface is used to output DC.

[0041] In a third aspect, an embodiment of the present application provides a charging device. The charging device includes at least one AC-DC power module as provided in the first aspect and any one of the possible implementation methods of the first aspect, at least one DC-DC power module, a power distribution unit, and at least one charging interface. The input end of the AC-DC power module is used to receive alternating current (AC), the output end of the AC-DC power module is connected to the DC bus of the charging device, the input end of the DC-DC power module is connected to the DC bus of the charging device, the output end of the DC-DC power module is connected to the input end of the power distribution unit, the output end of the power distribution unit is connected to the input end of the charging interface, and the output end of the charging interface is used to output DC power. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG1 is a schematic diagram of a charging pile provided in an embodiment of the present application;

[0043] FIG2 is a circuit connection diagram of an AC-DC power module provided in an embodiment of the present application;

[0044] FIG3 is a connection diagram of the interleaved parallel PFC circuit in FIG2 ;

[0045] FIG4 is a working state table of the circuit shown in FIG3 within one switching cycle;

[0046] FIG5 is a schematic diagram of an equivalent circuit of the circuit shown in FIG3 in one working state;

[0047] FIG6 is a schematic diagram of an equivalent circuit of the circuit shown in FIG3 in another working state;

[0048] FIG7 is a schematic diagram of an equivalent circuit of the circuit shown in FIG3 in another working state;

[0049] FIG8 is a schematic diagram of an equivalent circuit of the circuit shown in FIG3 in another working state;

[0050] FIG9 is another connection diagram of the interleaved parallel PFC circuit in FIG2 ;

[0051] FIG10 is another connection diagram of the interleaved parallel PFC circuit in FIG2 ;

[0052] FIG11 is another connection diagram of the interleaved parallel PFC circuit in FIG2 ;

[0053] FIG12 is a schematic diagram of a charging device provided in an embodiment of the present application;

[0054] FIG13 is a schematic diagram of another charging device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] For ease of understanding, the terms involved in the embodiments of the present application are first explained.

[0056] Connection: should be understood in a broad sense. For example, A and B are connected, which can be either directly connected or indirectly connected through an intermediary.

[0057] The terms "first," "second," etc., in the description are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features indicated. Therefore, a feature specified as "first," "second," etc. may explicitly or implicitly include one or more of the features.

[0058] With the development of new energy technologies, the number of electric vehicles is also increasing, and the slow charging speed of electric vehicles has always been one of the pain points of users. In order to solve this problem, the output power of the charging pile is usually increased to reduce the charging time of the electric vehicle. As shown in Figure 1, a schematic diagram of a charging pile provided in an embodiment of the present application is shown, and the charging pile 10 includes multiple AC-DC power modules, a power distribution unit and a charging interface. Among them, the AC-DC power module is used to convert alternating current into direct current; the power distribution unit is used to connect one of the multiple AC-DC power modules to one of the charging interfaces, or to connect at least two of the multiple AC-DC power modules in parallel or in series to one of the charging interfaces; the charging interface is used to connect the electric vehicle to charge the electric vehicle.

[0059] In order to increase the charging power of the electric vehicle, the AC-DC power module inside the charging pile 10 achieves high power output by adopting an interleaved parallel PFC circuit.

[0060] Figure 2 shows a circuit connection diagram of an AC-DC power module provided in an embodiment of the present application. The AC-DC power module 20 includes N interleaved parallel PFC circuits 201, where 1 ≤ N ≤ 3 and N is an integer. Each interleaved parallel PFC circuit 201 includes a PFC inductor 205, an autotransformer 207, a first rectifier bridge arm 209, and a second rectifier bridge arm 211. The autotransformer 207 includes a first winding 207-1 and a second winding 207-2. One end of the PFC inductor 205 receives AC power, and the other end of the PFC inductor connects one end of the first winding 207-1 to one end of the second winding 207-2. The other end of the first winding 207-1 is connected to the first rectifier bridge arm 209, and the other end of the second winding 207-2 is connected to the second rectifier bridge arm 211.

[0061] The first winding 207-1 and the second winding 207-2 have the same number of turns and are wound around the same magnetic core. The first rectifier bridge arm 209 and the second rectifier bridge arm 211 have the same circuit topology. The drive signals for the first rectifier bridge arm 209 and the second rectifier bridge arm 211 are phase-shifted by a certain angle. This configuration allows the output voltage ripple of the two rectifier bridge arms connected to the same phase of AC power to cancel each other out, reducing the impact of voltage ripple on the circuit.

[0062] Due to the parameter differences of the switching devices in the first rectifier bridge arm 209 and the switching devices in the second rectifier bridge arm 211, the switch drive delay, the different dead time, etc., the volt-second product of the autotransformer 207 will exceed the allowable value of the magnetic core, causing the magnetic core of the autotransformer 207 to saturate, which will cause the switching devices in the circuit to fail due to the saturation of the magnetic core of the autotransformer.

[0063] Based on this, an embodiment of the present application provides an AC-DC power module comprising N interleaved parallel PFC circuits and a controller as shown in FIG2 . The controller can determine whether the autotransformer's magnetic core is saturated based on the difference between the current flowing through the autotransformer's first winding and the current flowing through the autotransformer's second winding. If saturated, the controller adjusts the on-time of the switching tubes in the two rectifier bridge arms to reduce the excitation current in the autotransformer, thereby resolving the issue of autotransformer core saturation and protecting components in the circuit from failure due to autotransformer core saturation.

[0064] FIG2 illustrates the circuit connection method using an AC-DC power module including three interleaved parallel PFC circuits as an example. The three interleaved parallel PFC circuits are connected to a three-phase AC power supply to achieve high current output. In actual application, the number of interleaved parallel PFC circuits can be set according to the power requirements of the load. If the power required by the load is small, the input of the AC-DC power module 20 only needs to be connected to a single-phase AC power supply. In other words, the AC-DC power module 20 only needs to include one interleaved parallel PFC circuit. If the power required by the load is large, the input of the AC-DC power module 20 is connected to a three-phase AC power supply. In other words, the AC-DC power module 20 includes three interleaved parallel PFC circuits, each of which is connected to one phase of the three-phase AC power supply, and different interleaved parallel PFC circuits are connected to different phases of the AC power supply. This application does not limit the number of interleaved parallel PFC circuits; it can be set according to actual load requirements.

[0065] Below, taking a specific circuit as an example, the working principle of the AC-DC power module provided in the embodiment of the present application is described in detail.

[0066] Figure 3 shows a schematic diagram of a connection for the interleaved parallel PFC circuit in Figure 2. The interleaved parallel PFC circuit 301 includes a PFC inductor La, an autotransformer Ta, a first rectifier bridge arm Ra1, a second rectifier bridge arm Ra2, and bus capacitors. The bus capacitors include a positive bus capacitor C1 and a negative bus capacitor C2 connected in series. One end of the positive bus capacitor C1 is connected to the positive DC bus Bus+, and one end of the negative bus capacitor is connected to the negative DC bus Bus-.

[0067] The first rectifier bridge arm Ra1 includes a first diode Da1, a second diode Da2, a third diode Da3, a fourth diode Da4, a first switch Sa1, and a second switch Sa2. The first diode Da1, the second diode Da2, the third diode Da3, and the fourth diode Da4 are connected in series, with the cathode of the first diode Da1 connected to the positive DC bus and the anode of the fourth diode Da4 connected to the negative DC bus. One end of the first switch Sa1 is connected to the midpoint of the series connection of the first diode Da1 and the second diode Da2, and the other end of the first switch Sa1 is connected to the midpoint O of the bus capacitors C1 and C2. One end of the second switch Sa2 is connected to the midpoint of the series connection of the third diode Da3 and the fourth diode Da4, and the other end of the second switch Sa2 is connected to the midpoint O of the bus capacitors C1 and C2.

[0068] Similarly, the second rectifier bridge arm Ra2 includes a fifth diode Da5, a sixth diode Da6, a seventh diode Da7, an eighth diode Da8, a third switch Sa3, and a fourth switch Sa4. The fifth, sixth, seventh, and eighth diodes Da8 are connected in series, with the cathode of the fifth diode Da5 connected to the positive DC bus and the anode of the eighth diode Da8 connected to the negative DC bus. One end of the third switch Sa3 is connected to the midpoint of the series connection of the fifth and sixth diodes Da5 and Da6, and the other end of the third switch Sa3 is connected to the midpoint O of the bus capacitors C1 and C2. One end of the fourth switch Sa4 is connected to the midpoint of the series connection of the seventh and eighth diodes Da7 and Da8, and the other end of the fourth switch Sa4 is connected to the midpoint O of the bus capacitors C1 and C2.

[0069] It should be noted that the midpoint O of the bus capacitors C1 and C2 refers to any point between the two connected bus capacitors. The midpoint of two series-connected diodes refers to any point between the two connected diodes.

[0070] The autotransformer includes a first winding Ta1 and a second winding Ta2. The number of turns of the first winding Ta1 and the number of turns of the second winding Ta2 are equal. One end of the PFC inductor La is used to receive AC power, and the other end of the PFC inductor La is connected to one end of the first winding Ta1 and one end of the second winding Ta2. The other end of the first winding Ta1 is connected to the midpoint of the series connection of the second diode Da2 and the third diode Da3. The other end of the second winding Ta2 is connected to the midpoint of the series connection of the sixth diode Da6 and the seventh diode Da7.

[0071] Please refer to Figure 4, which shows the operating states of the interleaved parallel PFC circuit 301 within a switching cycle T when the phase voltage of the AC power output by the AC power source Ua is in the positive half-cycle. Switching cycle T is the period of the drive signal for the switches in the circuit. The interleaved parallel PFC circuit 301 has four operating states: during the first time period T1, Sa1 is on and Sa2 is off; during the second time period T2, Sa1 is on and Sa2 is on; during the third time period T3, Sa1 is off and Sa2 is on; and during the fourth time period T4, Sa1 is off and Sa2 is off.

[0072] The equivalent circuit diagrams of the interleaved parallel PFC circuit 301 with different switch combinations are shown in Figures 5 to 8. In the following circuit analysis, the current flowing in the interleaved parallel PFC circuit is assumed to be in the positive direction when the phase voltage of the AC power output by the AC power source Ua is in the positive half-cycle. That is, when the phase voltage of the AC power source Ua is in the positive half-cycle, the current Ia1 flowing through the first winding Ta1 detected by the current sensor 303 is greater than or equal to zero, and the current Ia2 flowing through the second winding Ta2 detected by the current sensor 304 is greater than or equal to zero. When the phase voltage of the AC power output by the AC power source Ua is in the negative half-cycle, the current Ia1 detected by the current sensor 303 is less than or equal to zero, and the current Ia2 detected by the current sensor 304 is less than or equal to zero.

[0073] Figure 5 is a schematic diagram of the equivalent circuit when the first switch Sa1 and the third switch Sa3 are simultaneously turned on. When the first switch Sa1 and the third switch Sa3 are simultaneously turned on, the voltage Va1 at the midpoint of the first rectifier bridge arm = 0, the voltage Va2 at the midpoint of the second rectifier bridge arm = 0V, and the voltage Vin at the bridge arm port = 0.5*(Va1+Va2) = 0V.

[0074] Figure 6 is a schematic diagram of the equivalent circuit when the first switch tube Sa1 is turned on and the third switch tube Sa3 is turned off. In this case, the voltage Va1 at the midpoint of the first rectifier bridge arm is 0V, the voltage Va2 at the midpoint of the second rectifier bridge arm is VBus, and the voltage Vin at the bridge arm port is 0.5*(Va1+Va2)=0.5*VBus. The voltage V across the first winding Ta1 is Ta1=Vin-Va1=0.5*Vbus, the voltage across the second winding Ta2 is V Ta2 =Vin-Va2=-0.5*Vbus.

[0075] Figure 7 is a schematic diagram of the equivalent circuit when the first switch tube Sa1 is turned off and the third switch tube Sa3 is turned on. In this case, the voltage Va1 at the midpoint of the first rectifier bridge arm = VBus, the voltage Va2 at the midpoint of the second rectifier bridge arm = 0V, and the voltage Vin at the bridge arm port = 0.5*(Va1+Va2) = 0.5*VBus. The voltage V across the second winding Ta2 is Ta2 =Vin-Va2=0.5*Vbus, the voltage across the first winding Ta1 is V Ta1 =Vin-Va1=-0.5*Vbus.

[0076] Figure 8 is a schematic diagram of the equivalent circuit when both the first switch tube Sa1 and the third switch tube Sa3 are turned off. In this case, the voltage Va1 at the midpoint of the first rectifier bridge arm = VBus, the voltage Va2 at the midpoint of the second rectifier bridge arm = VBus, and the voltage Vin at the bridge arm port = 0.5*(Va1+Va2) = VBus. The voltage V across the first winding Ta1 is Ta1 =Vin-Va1=0V, the voltage across the first winding Ta1 is V Ta1 =Vin-Va1=0V.

[0077] From the above analysis, it can be seen that when the phase voltage of the AC power output by the AC power supply Ua is in the positive half cycle, when the first switch tube Sa1 and the third switch tube Sa3 are not turned on at the same time, a voltage difference will be generated across the first winding Ta1 and the second winding Ta2. Taking the first winding Ta1 as an example, when the first switch tube Sa1 is turned on and the third switch tube Sa3 is turned off, V Ta1 =Vin-Va1=0.5*Vbus, when the first switch tube Sa1 is turned off and the third switch tube Sa3 is turned on, V Ta1 =Vin-Va1=-0.5*Vbus.

[0078] According to the volt-second balance principle, within a switching cycle T, when the circuit operates in steady state, the volt-second product of the autotransformer Ta is balanced, that is, 0.5*Vbus*T1 - 0.5*Vbus*T3 = 0. If the volt-second product of Ta1 is unbalanced within a switching cycle T, the excitation current in Ta1 will continue to accumulate, eventually leading to saturation of the autotransformer Ta's core. From the inductor voltage formula U = L*di / dt, we know that U*dt = L*di. Therefore, adjusting the excitation current within a switching cycle is equivalent to adjusting the volt-second product of Ta1, thereby achieving a balanced volt-second product of Ta1.

[0079] Similarly, if the voltage integral across Ta2 is not zero within a switching period T, the excitation current in Ta2 will continue to increase, eventually leading to saturation of the magnetic core of the autotransformer Ta.

[0080] Therefore, when the phase voltage of the AC power output by the AC power supply Ua is in the positive half cycle, the duty cycle of the drive signal of the first switching tube Sa1 and the third switching tube Sa3 can be adjusted to adjust the magnitude of the excitation current of the autotransformer Ta, so that the autotransformer does not operate in a saturated state.

[0081] When Ia1>0, Ia2>0 and Ia1-Ia2>0, it means that the cumulative on-time of the first switch tube Sa1 is greater than the cumulative on-time of the third switch tube Sa3; when Ia1>0, Ia2>0 and Ia1-Ia2<0, it means that the cumulative on-time of the third switch tube Sa3 is greater than the cumulative on-time of the first switch tube Sa1.

[0082] When the phase voltage of the AC power output by AC power source Ua is in the negative half-cycle, the second switching transistor Sa2 and the fourth switching transistor Sa4 alternately conduct. The circuit's operating principle is the same as that analyzed above and will not be further elaborated here. Similarly, by adjusting the duty cycle of the drive signals of the second switching transistor Sa2 and the fourth switching transistor Sa4, the excitation current of the autotransformer Ta can be adjusted, thereby preventing the autotransformer from operating in a saturated state.

[0083] When Ia1<0, Ia2<0 and Ia1-Ia2>0, it means that the cumulative on-time of the fourth switch tube Sa4 is greater than the cumulative on-time of the second switch tube Sa2; when Ia1<0, Ia2<0 and Ia1-Ia2<0, it means that the cumulative on-time of the second switch tube Sa2 is greater than the cumulative on-time of the fourth switch tube Sa4.

[0084] From the above analysis, it can be seen that based on the difference in the current of the two windings, the difference in the conduction time of the switch tubes in the two rectifier bridge arms can be determined. Therefore, by adjusting the duty cycle of the drive signal of the switch tube in the next switching cycle, the excitation current of the autotransformer Ta can be reduced, thereby solving the problem of core saturation of the autotransformer Ta.

[0085] Referring to Figure 3 , a first current detection module 303 is configured to detect current Ia1 flowing through the first winding Ta1, and a second current detection module 304 is configured to detect current Ia2 flowing through the second winding Ta2. A controller 302 is configured to obtain currents Ia1 and Ia2 and, based on the difference between the currents in the two windings, determine whether to adjust the duty cycle of the switch in the next switching cycle.

[0086] It should be noted that the position of the current detection module shown in FIG. 3 is only an example. The current detection module can be located at any position of the two autotransformer branches, as long as it can detect the current Ia1 flowing through the first winding Ta1 and the current Ia2 flowing through the second winding Ta2.

[0087] In a possible implementation, in response to the absolute value of the difference between the two winding currents being less than the preset value Imax, the controller 302 does not adjust the duty cycle of the driving signal of the switching transistor in the next switching cycle; in response to the absolute value of the difference between the two winding currents being greater than or equal to the preset value Imax, the controller 302 adjusts the duty cycle of the driving signal of the switching transistor in the next switching cycle to reduce the difference between the two winding currents.

[0088] Wherein, the preset value is the current intensity when the core of the autotransformer Ta reaches magnetic saturation, that is, the saturation current of the autotransformer.

[0089] Based on this implementation, not only can the problem of magnetic core saturation of the autotransformer Ta be solved, but also the controller 302 only starts to adjust the duty cycle of the driving signal of the switching transistor when the difference between the two winding currents reaches the preset value, which can simplify the control strategy of the controller.

[0090] In a possible implementation, in response to Ia1>0, Ia2>0 and Ia1 - Ia2≥Imax, the controller 302 is configured to reduce the duty cycle of the driving signal of the first switching transistor Sa1 in the next switching cycle.

[0091] Ia1>0 and Ia2>0 indicate that the phase voltage of the alternating current is in the positive half cycle, that is, in response to the phase voltage of the AC source Ua being in the positive half cycle and |Ia1 - Ia2|≥Imax and |Ia1|>|Ia2|, the controller 302 is configured to reduce the duty cycle of the driving signal of the first switching transistor Sa1 in the next switching cycle.

[0092] Wherein, |Ia1 - Ia2|≥Imax represents the absolute value of the difference between Ia1 and Ia2, |Ia1| represents the absolute value of Ia1, and |Ia2| represents the absolute value of Ia2.

[0093] It can be understood that by this adjustment method, the exciting current of the first winding Ta1 can be reduced. If in the next switching cycle, |Ia1 - Ia2|≥Imax and |Ia1|>|Ia2|, the controller 302 will continue to reduce the duty cycle of the driving signal of the first switching transistor Sa1 until |Ia1 - Ia2|<Imax, so that the magnetic core of the autotransformer Ta is not saturated, thereby preventing the electronic devices in the circuit from being damaged due to the magnetic core saturation of the autotransformer Ta.

[0094] In a possible implementation, in response to Ia1 > 0, Ia2 > 0, and Ia2 - Ia1 ≥ Imax, the controller 302 is configured to reduce the duty cycle of the driving signal of the third switching transistor Sa3 in the next switching cycle.

[0095] That is, in response to the phase voltage of the alternating current being in the positive half cycle, |Ia1 - Ia2| ≥ Imax, and |Ia2| > |Ia1|, the controller 302 is configured to reduce the duty cycle of the driving signal of the third switching transistor Sa3 in the next switching cycle.

[0096] It can be understood that by this adjustment method, the excitation current of the second winding Ta2 can be reduced. If in the next switching cycle, |Ia1 - Ia2| ≥ Imax and |Ia2| > |Ia1|, the controller 302 will continue to reduce the duty cycle of the driving signal of the third switching transistor Sa3 until |Ia1 - Ia2| < Imax, so as to prevent the magnetic core of the autotransformer Ta from saturating, and thus prevent the electronic devices in the circuit from being damaged due to the saturation of the magnetic core of the coupling transformer Ta.

[0097] In a possible implementation, in response to Ia1 < 0, Ia2 < 0, and Ia1 - Ia2 ≥ Imax, the controller 302 is configured to reduce the duty cycle of the driving signal of the fourth switching transistor Sa4 in the next switching cycle.

[0098] That is, in response to the phase voltage of the alternating current being in the negative half cycle, |Ia1 - Ia2| ≥ Imax, and |Ia1| < |Ia2|, the controller 302 is configured to reduce the duty cycle of the driving signal of the fourth switching transistor Sa4 in the next switching cycle.

[0099] It can be understood that by this adjustment method, the excitation current of the second winding Ta2 can be reduced. If in the next switching cycle, |Ia1 - Ia2| ≥ Imax and |Ia2| > |Ia1|, the controller 302 will continue to reduce the duty cycle of the driving signal of the fourth switching transistor Sa4 until |Ia1 - Ia2| < Imax, so as to prevent the magnetic core of the autotransformer Ta from saturating, and thus prevent the electronic devices in the circuit from being damaged due to the saturation of the magnetic core of the coupling transformer Ta.

[0100] In a possible implementation, in response to Ia1 < 0, Ia2 < 0, and Ia2 - Ia1 ≥ Imax, the controller 302 is configured to reduce the duty cycle of the driving signal of the second switching transistor Sa2 in the next switching cycle.

[0101] That is, in response to the phase voltage of the alternating current being in the negative half cycle, |Ia1 - Ia2| ≥ Imax, and |Ia2| < |Ia1|, the controller 302 is configured to reduce the duty cycle of the driving signal of the second switching transistor Sa2 in the next switching cycle.

[0102] It can be understood that by this adjustment method, the excitation current of the first winding Ta1 can be reduced. If in the next switching cycle, |Ia1 - Ia2| ≥ Imax and |Ia1| > |Ia2|, the controller 302 will continue to reduce the duty ratio of the driving signal of the second switching transistor Sa2 until |Ia1 - Ia2| < Imax, so as to prevent the magnetic core of the autotransformer Ta from being saturated, and thus prevent the electronic devices in the circuit from being damaged due to the saturation of the magnetic core of the coupling transformer Ta.

[0103] It should be noted that the operating frequencies of the first switching transistor Sa1, the second switching transistor Sa2, the third switching transistor Sa3, and the fourth switching transistor Sa4 are greater than the operating frequency of the alternating current.

[0104] In a possible implementation manner, as shown in FIG. 9, it is a schematic connection diagram of another interleaved parallel PFC circuit provided by an embodiment of the present application. The working principle of the circuit shown in FIG. 9 is the same as the above analysis, and will not be elaborated here. Different from FIG. 3, the third current detection module is used to detect the total current Iin flowing into the interleaved parallel PFC circuit, and the fourth current detection module is used to detect the current Ia1 flowing through the first winding Ta1, then the current Ia2 flowing through the second winding Ta2 = Iin - Ia1. Or, the third current detection module is used to detect the total current Iin flowing into the interleaved parallel PFC circuit, and the fourth current detection module is used to detect the current Ia2 flowing through the second winding Ta2, then the current Ia1 flowing through the first winding Ta1 = Iin - Ia2.

[0105] As shown in FIG. 10, it is a schematic connection diagram of another interleaved parallel PFC circuit provided by an embodiment of the present application. The interleaved parallel PFC circuit 1001 includes a PFC inductor La, an autotransformer Ta, a first rectifier arm, a second rectifier arm, and a bus capacitor. The bus capacitor includes a positive bus capacitor C1 and a negative bus capacitor C2 connected in series. One end of the positive bus capacitor C1 is connected to the positive DC bus Bus+, the other end of the positive bus capacitor C1 is connected to the midpoint O of the bus capacitor, one end of the negative bus capacitor C2 is connected to the midpoint O of the bus capacitor, and the other end of the negative bus capacitor is connected to the negative DC bus Bus-.

[0106] The first rectifier arm includes a first diode Da1, a second diode Da2, and a first bidirectional switching transistor Sa1. Among them, the first diode Da1 and the second diode Da2 are connected in series. The cathode of the first diode Da1 is connected to the positive DC bus, and the anode of the second diode Da2 is connected to the negative DC bus. One end of the first bidirectional switching transistor Sa1 is connected to the midpoint of the series connection of the first diode Da1 and the second diode Da2, and the other end of the first bidirectional switching transistor Sa1 is connected to the midpoint O of the bus capacitors C1 and C2.

[0107] Similarly, the second rectifier bridge arm includes a third diode Da3, a fourth diode Da4, and a second bidirectional switch Sa2. The third and fourth diodes Da3 and Da4 are connected in series, with the cathode of the third diode Da3 connected to the positive DC bus and the anode of the fourth diode Da4 connected to the negative DC bus. One end of the second bidirectional switch Sa2 is connected to the midpoint of the series connection of the third and fourth diodes Da3 and Da4, and the other end of the second bidirectional switch Sa2 is connected to the midpoint O of the bus capacitors C1 and C2.

[0108] The autotransformer includes a first winding Ta1 and a second winding Ta2. The number of turns of the first winding Ta1 and the number of turns of the second winding Ta2 are equal. One end of the PFC inductor La is used to receive AC power, and the other end of the PFC inductor La is connected to one end of the first winding Ta1 and one end of the second winding Ta2. The other end of the first winding Ta1 is connected to the midpoint of the series connection of the first diode Da1 and the second diode Da2. The other end of the second winding Ta2 is connected to the midpoint of the series connection of the third diode Da3 and the fourth diode Da4.

[0109] The first bidirectional switch Sa1 includes two switch tubes, and the driving timing of the two switch tubes is the same. The second bidirectional switch Sa2 includes two switch tubes, and the driving timing of the two switch tubes is the same.

[0110] The working principle of this circuit is the same as that of the above-mentioned interleaved parallel PFC circuit. When the first bidirectional switch tube Sa1 and the second bidirectional switch tube Sa2 are not turned on at the same time, the autotransformer Ta will generate an excitation current.

[0111] In a possible implementation, in response to Ia1>0, Ia2>0, and Ia1-Ia2≥Imax, the controller 1003 is configured to reduce the duty cycle of the driving signal of the first bidirectional switch Sa1 in the next switching cycle.

[0112] That is, in response to the AC phase voltage being in the positive half cycle, |Ia1-Ia2|≥Imax and |Ia1|>|Ia2|, the controller 1003 is configured to reduce the duty cycle of the driving signal of the first bidirectional switch Sa1 in the next switching cycle.

[0113] In a possible implementation, in response to Ia1<0, Ia2<0, and Ia2-Ia1≥Imax, the controller 1003 is configured to reduce the duty cycle of the driving signal of the first bidirectional switch Sa1 in the next switching cycle.

[0114] That is, in response to the phase voltage of the alternating current being in the negative half cycle, |Ia2 - Ia1| ≥ Imax, and |Ia2| < |Ia1|, the controller 1003 is configured to reduce the duty cycle of the driving signal of the first bidirectional switch Sa1 in the next switching cycle.

[0115] In summary, in response to |Ia1 - Ia2| ≥ Imax and |Ia1| > |Ia2|, the controller 1003 is configured to reduce the duty cycle of the driving signal of the first bidirectional switch Sa1 in the next switching cycle.

[0116] It can be understood that by this adjustment method, the excitation current of the first winding Ta1 can be reduced. If in the next switching cycle, |Ia1 - Ia2| ≥ Imax and |Ia1| > |Ia2|, the controller 1003 will continue to reduce the duty cycle of the driving signal of the first bidirectional switch Sa1 until |Ia1 - Ia2| < Imax, so as to prevent the magnetic core of the autotransformer Ta from saturating, and thus prevent the electronic devices in the circuit from being damaged due to the saturation of the magnetic core of the autotransformer Ta.

[0117] In a possible implementation, in response to Ia1 > 0, Ia2 > 0, and Ia2 - Ia1 ≥ Imax, the controller 1003 is configured to reduce the duty cycle of the driving signal of the second bidirectional switch Sa2 in the next switching cycle.

[0118] That is, in response to the phase voltage of the alternating current being in the positive half cycle, |Ia2 - Ia1| ≥ Imax, and |Ia2| > |Ia1|, the controller 1003 is configured to reduce the duty cycle of the driving signal of the second bidirectional switch Sa2 in the next switching cycle.

[0119] In a possible implementation, in response to Ia1 < 0, Ia2 < 0, and Ia1 - Ia2 ≥ Imax, the controller 1003 is configured to reduce the duty cycle of the driving signal of the second bidirectional switch Sa2 in the next switching cycle.

[0120] In response to the phase voltage of the alternating current being in the negative half cycle, |Ia1 - Ia2| ≥ Imax, and |Ia1| < |Ia2|, the controller 302 is configured to reduce the duty cycle of the driving signal of the second bidirectional switch Sa2 in the next switching cycle.

[0121] In summary, in response to |Ia1 - Ia2| ≥ Imax and |Ia1| < |Ia2|, the controller 302 is configured to reduce the duty cycle of the driving signal of the second bidirectional switch Sa2 in the next switching cycle.

[0122] It can be understood that the excitation current of the second winding Ta2 can be reduced through this adjustment method. If |Ia1 - Ia2| ≥ Imax and |Ia1| < |Ia2| in the next switching cycle, the controller 1003 will continue to reduce the duty cycle of the driving signal of the second bidirectional switch Sa2 until |Ia1 - Ia2| < Imax, so as to prevent the magnetic core of the autotransformer Ta from being saturated, and thus prevent the electronic devices in the circuit from being damaged due to the saturation of the magnetic core of the autotransformer Ta.

[0123] It should be noted that the operating frequencies of the first bidirectional switch Sa1 and the second bidirectional switch Sa2 are greater than the operating frequency of the AC source.

[0124] As shown in FIG. 11, it is a schematic diagram of another interleaved parallel PFC circuit provided by an embodiment of the present application. The interleaved parallel PFC circuit 1101 includes a PFC inductor La, an autotransformer Ta, a first rectifier arm Ra1, a second rectifier arm Ra1, and a bus capacitor. The bus capacitor includes a positive bus capacitor C1 and a negative bus capacitor C2 connected in series. One end of the positive bus capacitor C1 is connected to the positive DC bus Bus+, and one end of the negative bus capacitor is connected to the negative DC bus Bus-.

[0125] The first rectifier arm Ra1 includes a first switch Sa1 and a second switch Sa2 connected in series. One end of the first switch Sa1 is used to connect to the positive DC bus, and one end of the second switch Sa2 is used to connect to the negative DC bus.

[0126] The second rectifier arm Ra2 includes a third switch Sa3 and a fourth switch Sa4 connected in series. One end of the third switch Sa3 is used to connect to the positive DC bus, and one end of the fourth switch Sa4 is used to connect to the negative DC bus. <着

[0127] The autotransformer includes a first winding Ta1 and a second winding Ta2, and the number of turns of the first winding Ta1 is equal to the number of turns of the second winding Ta2. One end of the PFC inductor La is used to receive alternating current, and the other end of the PFC inductor La is connected to one end of the first winding Ta1 and one end of the second winding Ta2. The other end of the first winding Ta1 is connected to the midpoint of the series connection of the first switch Sa1 and the second switch Sa2, and the other end of the second winding Ta2 is connected to the midpoint of the series connection of the third switch Sa3 and the fourth switch Sa4.

[0128] Among them, the operating frequencies of the switches Sa1, Sa2, Sa3, and Sa4 are greater than the frequency of the alternating current Ua.

[0129] The working principle of this circuit is the same as that of the above interleaved parallel PFC circuit. When the first switching transistor Sa1 and the third switching transistor Sa3 are not conducting simultaneously, the autotransformer Ta will generate an exciting current; or, when the second switching transistor Sa2 and the fourth switching transistor Sa4 are not conducting simultaneously, the autotransformer Ta will generate an exciting current.

[0130] In a possible implementation, in response to the phase voltage of the AC source Ua being in the positive half-cycle, |Ia1 - Ia2| ≥ Imax, and |Ia1| > |Ia2|, the controller 1103 is configured to reduce the duty cycle of the drive signal of the second switching transistor Sa2 in the next switching cycle.

[0131] It can be understood that by this adjustment method, the exciting current of the first winding Ta1 can be reduced. If in the next switching cycle, |Ia1 - Ia2| ≥ Imax and |Ia1| > |Ia2|, the controller 1103 will continue to reduce the duty cycle of the drive signal of the second switching transistor Sa2 until |Ia1 - Ia2| < Imax, so as to prevent the core of the autotransformer Ta from saturating, and thus prevent the electronic devices in the circuit from being damaged due to the saturation of the core of the autotransformer Ta.

[0132] In a possible implementation, in response to the phase voltage of the alternating current being in the positive half-cycle, |Ia1 - Ia2| ≥ Imax, and |Ia2| > |Ia1|, the controller 1103 is configured to reduce the duty cycle of the drive signal of the fourth switching transistor Sa4 in the next switching cycle.

[0133] It can be understood that by this adjustment method, the exciting current of the second winding Ta2 can be reduced. If in the next switching cycle, |Ia1 - Ia2| ≥ Imax and |Ia2| > |Ia1|, the controller 1103 will continue to reduce the duty cycle of the drive signal of the fourth switching transistor Sa4 until |Ia1 - Ia2| < Imax, so as to prevent the core of the autotransformer Ta from saturating, and thus prevent the electronic devices in the circuit from being damaged due to the saturation of the core of the autotransformer Ta.

[0134] In a possible implementation, in response to the phase voltage of the alternating current being in the negative half-cycle, |Ia1 - Ia2| ≥ Imax, and |Ia1| < |Ia2|, the controller 1103 is configured to reduce the duty cycle of the drive signal of the third switching transistor Sa3 in the next switching cycle.

[0135] It can be understood that the exciting current of the second winding Ta2 can be reduced by this adjustment method. If |Ia1 - Ia2| ≥ Imax and |Ia2| > |Ia1| in the next switching period, the controller 1103 will continue to reduce the duty cycle of the driving signal of the third switching transistor Sa3 until |Ia1 - Ia2| < Imax, so as to prevent the magnetic core of the autotransformer Ta from being saturated, and thus prevent the electronic devices in the circuit from being damaged due to the saturation of the magnetic core of the autotransformer Ta.

[0136] In a possible implementation manner, in response to the phase voltage of the alternating current being in the negative half-cycle, |Ia1 - Ia2| ≥ Imax and |Ia2| < |Ia1|, the controller 1103 is configured to reduce the duty cycle of the driving signal of the first switching transistor Sa1 in the next switching period.

[0137] It can be understood that the exciting current of the first winding Ta1 can be reduced by this adjustment method. If |Ia1 - Ia2| ≥ Imax and |Ia1| > |Ia2| in the next switching period, the controller 1103 will continue to reduce the duty cycle of the driving signal of the first switching transistor Sa1 until |Ia1 - Ia2| < Imax, so as to prevent the magnetic core of the autotransformer Ta from being saturated, and thus prevent the electronic devices in the circuit from being damaged due to the saturation of the magnetic core of the autotransformer Ta.

[0138] Based on this, an embodiment of the present application further provides a charging device. As shown in FIG. 12, the charging device 120 includes at least one of the above-mentioned AC-DC power modules 1201, a power distribution unit 1203, and at least one charging interface 1205. The input end of the AC-DC power module 1201 is used to receive alternating current, the output end of the AC-DC power module 1201 is connected to the input end of the power distribution unit 1203, the output end of the power distribution unit 1203 is used to connect to the input end of the charging interface 1205, and the output end of the charging interface 1205 is used to output direct current.

[0139] Among them, the AC-DC module 1201 is used to convert alternating current into direct current, and the power distribution unit 1203 is used to distribute the direct current output by the AC-DC power module 1201 to one of the charging interfaces 1205, so as to charge the device to be charged.

[0140] As shown in FIG13 , another charging device is provided in an embodiment of the present application. The charging device 130 includes at least one AC-DC power module 1301 as described above, at least one DC-DC power module 1303, a power distribution unit 1305, and at least one charging interface 1307. The input end of the AC-DC power module 1301 is used to receive alternating current, the output end of the AC-DC power module 1301 is connected to the DC bus of the charging device, the input end of the DC-DC power module 1303 is connected to the DC bus of the charging device, the output end of the DC-DC power module 1303 is connected to the input end of the power distribution unit 1305, the output end of the power distribution unit 1305 is connected to the input end of the charging interface 1307, and the output end of the charging interface 1307 is used to output direct current.

[0141] It should be noted that the AC-DC power module provided in the embodiment of the present application can be applied not only to the above-mentioned charging equipment, but also to devices requiring rectification such as rectifiers or server power supplies, and the present application does not impose any restrictions on this.

[0142] The above description is merely a specific implementation of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. An AC-DC power module, characterized in that: The AC-DC power module includes a controller and N groups of interleaved parallel PFC circuits, wherein: Each group of the interleaved parallel PFC circuits is used to convert one phase of the AC power supply into DC power and output it to the DC bus, wherein 1≤N≤3, and N is an integer; Each group of the interleaved parallel PFC circuits comprises a PFC inductor, an autotransformer, a first rectifier bridge arm and a second rectifier bridge arm, the autotransformer comprises a first winding and a second winding, one end of the PFC inductor is used to receive the alternating current, the other end of the PFC inductor is used to connect one end of the first winding and one end of the second winding, the other end of the first winding is used to connect the first rectifier bridge arm, and the other end of the second winding is used to connect the second rectifier bridge arm; The controller is used to: In response to the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the first winding being greater than the absolute value of the current of the second winding, reducing the duty cycle of the drive signal of the switch tube in the first rectifier bridge arm whose operating frequency is greater than the frequency of the alternating current in the next switching cycle; or In response to the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to a preset value, and the absolute value of the current of the second winding being greater than the absolute value of the current of the first winding, the duty cycle of the drive signal of the switch tube in the second rectifier bridge arm whose operating frequency is greater than the frequency of the alternating current in the next switching cycle is reduced.

2. The power module according to claim 1, characterized in that: The N groups of staggered parallel PFC circuits include bus capacitors, which include a positive bus capacitor and a negative bus capacitor connected in series, one end of the positive bus capacitor is connected to a positive DC bus, and the other end of the negative bus capacitor is connected to a negative DC bus.

3. The power module according to claim 2, characterized in that: The first rectifier bridge arm comprises a first diode, a second diode, a third diode, a fourth diode, a first switch tube and a second switch tube, wherein the first diode, the second diode, the third diode and the fourth diode are connected in series, the cathode of the first diode is connected to the positive DC bus, the anode of the fourth diode is connected to the negative DC bus, one end of the first switch tube is connected, the other end of the first switch tube is connected to the midpoint of the bus capacitor, one end of the second switch tube is connected to the midpoint of the series connection of the third diode and the fourth diode, and the other end of the second switch tube is connected to the midpoint of the bus capacitor; The second rectifier bridge arm includes a fifth diode, a sixth diode, a seventh diode, an eighth diode, a third switch tube and a fourth switch tube, wherein the fifth diode, the sixth diode, the seventh diode and the eighth diode are connected in series, the cathode of the fifth diode is connected to the positive DC bus, the anode of the eighth diode is connected to the negative DC bus, one end of the third switch tube is connected to the midpoint of the series connection of the fifth diode and the sixth diode, the other end of the third switch tube is connected to the midpoint of the bus capacitor, one end of the fourth switch tube is connected to the midpoint of the series connection of the seventh diode and the eighth diode, and the other end of the fourth switch tube is connected to the midpoint of the bus capacitor.

4. The power module according to claim 3, characterized in that: The controller is used to: In response to the phase voltage of the alternating current being in the positive half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to the preset value, and the absolute value of the current of the first winding being greater than the absolute value of the current of the second winding, the duty cycle of the drive signal of the first switching tube in the next switching cycle is reduced.

5. The power module according to claim 3, characterized in that: The controller is used to: In response to the phase voltage of the alternating current being in the positive half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to the preset value, and the absolute value of the current of the first winding being less than the absolute value of the current of the second winding, the duty cycle of the drive signal of the third switch tube in the next switching cycle is reduced.

6. The power module according to claim 3, characterized in that: The controller is used to: In response to the phase voltage of the alternating current being in a negative half cycle, the current of the first winding and the current of the second winding The absolute value of the difference is greater than or equal to the preset value and the absolute value of the current of the first winding is greater than the absolute value of the current of the second winding, thereby reducing the duty cycle of the drive signal of the second switch tube in the next switching cycle.

7. The power module according to claim 3, characterized in that: The controller is used to: In response to the phase voltage of the alternating current being in a negative half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to the preset value, and the absolute value of the current of the first winding being less than the absolute value of the current of the second winding, the duty cycle of the drive signal of the fourth switch tube in the next switching cycle is reduced.

8. The power module according to claim 1, characterized in that: The first rectifier bridge arm comprises a first switch tube and a second switch tube connected in series, one end of the first switch tube is used to connect the positive DC bus, and one end of the second switch tube is used to connect the negative DC bus; The second rectifier bridge arm comprises a third switch tube and a fourth switch tube connected in series; one end of the third switch tube is used to connect the positive DC bus, and one end of the fourth switch tube is used to connect the negative DC bus; The other end of the first winding is used to connect the midpoint of the series connection of the first switch tube and the second switch tube, and the other end of the second winding is used to connect the midpoint of the series connection of the third switch tube and the fourth switch tube.

9. The power module according to claim 8, characterized in that: The controller is used to: In response to the phase voltage of the alternating current being in the positive half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to the preset value, and the absolute value of the current of the first winding being greater than the absolute value of the current of the second winding, the duty cycle of the drive signal of the second switch tube in the next switching cycle is reduced.

10. The power module according to claim 8, characterized in that: The controller is used to: In response to the phase voltage of the alternating current being in the positive half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to the preset value, and the absolute value of the current of the first winding being less than the absolute value of the current of the second winding, the duty cycle of the drive signal of the fourth switch tube in the next switching cycle is reduced.

11. The power module according to claim 8, characterized in that: The controller is used to: In response to the phase voltage of the alternating current being in a negative half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to the preset value, and the absolute value of the current of the first winding being greater than the absolute value of the current of the second winding, the duty cycle of the drive signal of the first switching tube in the next switching cycle is reduced.

12. The power module according to claim 8, characterized in that: The controller is used to: In response to the phase voltage of the alternating current being in a negative half cycle, the absolute value of the difference between the current of the first winding and the current of the second winding being greater than or equal to the preset value, and the absolute value of the current of the first winding being less than the absolute value of the current of the second winding, the duty cycle of the drive signal of the third switch tube in the next switching cycle is reduced.

13. A charging device, characterized in that: The charging device comprises an AC-DC power module as claimed in any one of claims 1 to 12, at least one DC-DC power module, a power distribution unit and at least one charging interface, wherein: The input end of the AC-DC power module is used to receive alternating current, the output end of the AC-DC power module is connected to the DC bus of the charging device, the input end of the DC-DC power module is connected to the DC bus of the charging device, the output end of the DC-DC power module is connected to the input end of the power distribution unit, the output end of the power distribution unit is connected to the input end of the charging interface, and the output end of the charging interface is used to output direct current.

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