Power supply circuit suitable for three-phase power and power factor correction method

Abstract

The invention provides a power supply circuit suitable for three-phase power and a power factor correction method, and belongs to the technical field of power supplies. The power supply circuit comprises three single-stage power modules, the input ends of the three single-stage power modules are respectively configured to receive three line voltage / phase voltage of a three-phase alternating current system, and the output ends of the three single-stage power modules are arranged in parallel. The power supply circuit provided by the invention is low in cost, high in efficiency, simple to control and easy to expand.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of power supply, and in particular relates to a power supply circuit and a power correction method applicable to three-phase power. Background Art

[0002] With the development of new energy electric vehicles, charging piles are becoming more and more popular. High-power fast charging piles usually use three-phase AC input for power supply. The common three-phase AC input power conversion topology generally adopts a two-stage architecture, including power factor correction (Power Factor Correction, referred to as PFC) and DC-DC converter (abbreviated as DC-DC converter).

[0003] However, the use of a two-stage architecture to achieve power conversion and transmission requires not only a large number of components but also complex circuit connections, resulting in problems such as high cost, large energy loss, poor stability, low conversion rate, and poor scalability. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art and to provide a power supply circuit and a power factor control method suitable for three-phase electricity which are low in cost, high in efficiency and simple to control.

[0005] In order to achieve the above-mentioned objectives, in a first aspect, an embodiment of the present disclosure provides a power supply circuit suitable for three-phase electricity, wherein the power supply circuit includes three single-stage power modules, and the input ends of the three single-stage power modules are respectively configured to receive three line voltages / phase voltages of a three-phase alternating current system, and the output ends of the three single-stage power modules are arranged in parallel.

[0006] In some embodiments, input ends of the three single-stage power modules are respectively connected to the AB phase, BC phase, and AC phase of a three-phase alternating current system.

[0007] In some embodiments, input ends of the three single-stage power modules are respectively connected to phase A and a neutral line, phase B and a neutral line, and phase C and a neutral line of a three-phase AC power system.

[0008] In some embodiments, each of the single-stage power modules includes a rectifier unit and a power conversion unit, wherein the rectifier unit is configured to receive a line voltage / phase voltage of the three-phase AC power system and convert the line voltage / phase voltage into a DC voltage; the power conversion unit is connected to the output end of the rectifier unit and is configured to perform voltage conversion on the DC voltage so that the output power of the power conversion unit meets the load requirements.

[0009] In some embodiments, the output ends of the power conversion units are connected in parallel.

[0010] In some embodiments, the power conversion unit includes at least one power conversion sub-unit, each of which includes an energy storage capacitor, a switching tube, a transformer, an inductor and a diode; wherein the first end of the switching tube is connected to the first output end of the rectifier unit; the second end of the switching tube is connected to the first end of the first primary winding of the transformer; the second end of the first primary winding of the transformer is connected to the second output end of the rectifier unit; the first end of the first secondary winding of the transformer is connected to the first end of the energy storage capacitor, and the second end of the energy storage capacitor is connected to the first end of the diode and the first end of the inductor; the second end of the first secondary winding of the transformer is connected to the second end of the diode.

[0011] In some embodiments, when the power conversion unit includes at least two power conversion sub-units, the output ends of the at least two power conversion sub-units are connected in parallel.

[0012] In some embodiments, the power supply circuit also includes a power factor correction unit, which is connected to the power conversion unit. The power factor correction unit is configured to control the state of the switching tube based on the input parameters and output parameters of the power conversion unit to achieve power factor correction of the power supply circuit.

[0013] In some embodiments, the power factor correction unit includes a voltage loop, three current loops corresponding to three single-stage power modules, and three control units, wherein:

[0014] The input end of the voltage loop is connected to the output end of any power conversion unit in the three single-stage power modules;

[0015] The output end of the voltage loop is connected to the input ends of the three current loops respectively;

[0016] The input end of each current loop is also connected to the first output end and the second output end of the rectifier unit in the corresponding single-stage power module;

[0017] The output ends of the three current loops are respectively connected to the first ends of the three control units;

[0018] The second ends of the three control units are respectively connected to the control ends of the three switch tubes in the three single-stage power modules.

[0019] In some embodiments, the voltage loop comprises:

[0020] a voltage comparison unit connected to the output end of any of the power conversion units in the three single-stage power modules, and configured to compare the output voltage of the power conversion unit with a reference voltage to generate a first comparison result;

[0021] The voltage compensation network is connected to the voltage comparison unit and is configured to generate a first feedback voltage according to the first comparison result.

[0022] In some embodiments, for each current loop corresponding to a single-stage power module, the current loop includes:

[0023] a reference current generating unit connected to the output end of the voltage compensation network and the second output end of the rectifying unit in the single-stage power module, and configured to multiply the first feedback voltage by the input voltage of the power conversion unit in the single-stage power module to obtain a reference current;

[0024] a current comparison unit, connected to the reference current generation unit and the first output terminal of the rectification unit respectively, and configured to compare the reference current with the input current of the power conversion unit to generate a second comparison result;

[0025] The current compensation network is connected to the current comparison unit and is configured to generate a second feedback voltage according to the second comparison result.

[0026] In some embodiments, for a control unit corresponding to each single-stage power module, a first end of the control unit is connected to a current compensation network in a current loop corresponding to the single-stage power module, and a second end of the control unit is connected to a control end of a switch tube in the single-stage power module, and is configured to control the state of the switch tube based on a second feedback voltage generated by the current compensation network.

[0027] In some embodiments, for each of the single-stage power modules,

[0028] The power conversion unit also includes a resistor, an input capacitor and an output capacitor; wherein,

[0029] The first end of the input capacitor is connected to the second output end of the rectifier unit;

[0030] The second end of the input capacitor is connected to the first end of the resistor and the first end of the switch tube;

[0031] The second end of the resistor is connected to the first output end of the rectifier unit;

[0032] The first end of the output capacitor is connected to the second end of the inductor, and the second end of the output capacitor is connected to the second end of the first secondary winding of the transformer.

[0033] In some embodiments, the power factor correction unit further includes a second secondary winding arranged on the transformer of each single-stage power module; wherein,

[0034] The second secondary winding of each transformer is connected to a control unit connected to a switch tube of a corresponding single-stage power module and is configured to perform voltage detection on the transformer and output a voltage detection result;

[0035] The control unit is configured to control the state of the switch tube based on the voltage detection result and the second feedback voltage.

[0036] In a second aspect, an embodiment of the present disclosure further provides a method for power factor correction based on a power supply circuit, the method being applied to a power supply circuit as described in any one of the first aspects above, the method comprising:

[0037] Collecting the output voltage of any single-stage power module, and comparing the output voltage with a reference voltage to generate a first comparison result;

[0038] generating a first feedback voltage according to the first comparison result;

[0039] Multiplying the first feedback voltage by the input voltages of the three single-stage power modules respectively to obtain three reference currents;

[0040] Respectively comparing the three reference currents with the three input currents of the three single-stage power modules to generate three second comparison results;

[0041] generating three second feedback voltages according to the three second comparison results respectively;

[0042] The states of the switch tubes in the three single-stage power modules are controlled respectively based on the three second feedback voltages to correct the power factor of the power supply circuit.

[0043] The present disclosure is applicable to a three-phase AC system by connecting three phases of a three-phase AC system to three single-stage power modules, and the outputs of the three single-stage power modules are connected in parallel. Among them, the power supply circuit provided by the present disclosure can adopt a three-phase three-wire AC input, and each of the three line voltages has one or more power conversion submodules, and multiple power conversion submodules are output in parallel. The power supply circuit provided by the present disclosure can also adopt a three-phase four-wire AC input, and each of the three phase voltages has one or more power conversion submodules, and multiple power conversion submodules are output in parallel. In addition, the power factor correction method provided by the present disclosure is that all parallel modules (including three single-stage power modules in parallel, and multiple power conversion submodules in parallel in each single-stage power module) share a voltage loop, and each single-stage power module has a current loop, and the switch tube voltage is controlled to be turned on when the switch tube voltage is at the bottom position. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1A-1B They are schematic diagrams of two topological structures of three-phase power factor correction provided in the prior art;

[0046] Figure 2A-2B They are schematic diagrams of two topological structures of DC-DC conversion provided in the prior art;

[0047] Figure 3 A structural block diagram of a power supply circuit provided in an embodiment of the present disclosure;

[0048] Figure 4 A circuit diagram of a power supply circuit provided in an embodiment of the present disclosure;

[0049] Figure 5 A circuit diagram of another power supply circuit provided in an embodiment of the present disclosure;

[0050] Figure 6 A circuit diagram of another power supply circuit provided in an embodiment of the present disclosure;

[0051] Figure 7 A working waveform of a power supply circuit provided by an embodiment of the present disclosure;

[0052] Figure 8 A continuous conduction mode control logic block diagram taking a single power conversion unit as an example provided in an embodiment of the present disclosure;

[0053] Fig. 9 A flow chart of a power factor correction method provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail and completely in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0055] Commonly used two-stage three-phase power factor correction topologies include three-phase VIENNA (such as Figure 1A As shown) and six-tube three-bridge arm circuit (as shown Figure 1BAs shown); the DC-DC conversion topology commonly used is the full-bridge LLC circuit (as shown Figure 2A As shown) and three-phase LLC circuit (as Figure 2B shown).

[0056] refer to Figure 1A-1B as well as Figure 2A-2B It can be seen that the use of a two-stage architecture to achieve power conversion and transmission requires many components and complex circuit connections, and has problems such as high cost, large energy loss, poor stability, low conversion rate, and poor scalability.

[0057] Based on the above problems existing in the two-stage architecture, the present disclosure proposes a single-stage topology structure to realize power conversion and transmission, and realizes power factor correction, electrical isolation and output voltage and current adjustment through a single-stage circuit. The power supply circuit provided by the present disclosure has low cost, high efficiency, simple control and easy expansion.

[0058] In a first aspect, an embodiment of the present disclosure provides a power supply circuit suitable for three-phase electricity.

[0059] Figure 3 A structural block diagram of a power supply circuit provided in an embodiment of the present disclosure. Figure 4 A circuit diagram of a power supply circuit provided in an embodiment of the present disclosure. Figure 5 A circuit diagram of another power supply circuit provided by an embodiment of the present disclosure. Figure 3-Figure 5 As shown, the power supply circuit includes three single-stage power modules 1, the input ends of the three single-stage power modules 1 are respectively configured to receive three line voltages / phase voltages of a three-phase AC power system, and the output ends of the three single-stage power modules 1 are arranged in parallel.

[0060] The power circuit architecture provided by the embodiment of the present disclosure is composed of three single-stage power modules 1 connected in parallel. Compared with the two-stage architecture used in the prior art to realize power conversion and transmission, the power circuit provided by the present disclosure has simple circuit connection, low cost and strong scalability.

[0061] In some embodiments, the input ends of the three single-stage power modules 1 are respectively connected to the AB phase, BC phase, and AC phase of the three-phase AC system. Figure 4 shown.

[0062] In some embodiments, the input ends of the three single-stage power modules are respectively connected to the A phase and the neutral line N, the B phase and the neutral line N, and the C phase and the neutral line N of the three-phase AC power system. Figure 5 shown.

[0063] in, Figure 4The circuit diagram is a three-phase three-wire system, that is, the three-phase AC system has only three lines, namely three phase lines (A, B, C), and the three phase lines form three line voltages. The power supply circuit provided by the present disclosure can generate a large power by adopting a three-phase three-wire AC input, and is suitable for high-voltage power transmission and high-power equipment.

[0064] Figure 5 It is a three-phase four-wire circuit diagram, that is, the three-phase AC system has four lines, namely three phase lines (A, B, C) and one neutral line (N), and the three phase lines and one neutral line form three phase voltages. The power supply circuit provided by the present disclosure adopts a three-phase four-wire AC input, and the power generated is relatively small, which is suitable for low-voltage power supply and provides a safer power supply environment. At the same time, the neutral line can also reduce the risk of electric shock and equipment failure.

[0065] Figure 4 and Figure 5 The power supply circuit structure is basically the same, the only difference is that Figure 4 The input ends of the three single-stage power modules 1 are respectively configured to receive three line voltages of the three-phase AC power system, and Figure 5 The input ends of the three single-stage power modules 1 are respectively configured to receive three phase voltages of a three-phase alternating current system.

[0066] The power supply circuit provided in the embodiment of the present disclosure can be directly connected to the phase voltage or directly connected to the line voltage. The specific connection can be flexibly determined according to actual needs to meet different application scenarios.

[0067] like Figure 3-Figure 5 As shown, in some embodiments, each single-stage power module 1 includes a rectifier unit 10 and a power conversion unit 20. The rectifier unit 10 is configured to receive a line voltage / phase voltage of the three-phase AC system and convert the line voltage / phase voltage into a DC voltage. The power conversion unit 20 is connected to the output end of the rectifier unit 10 and is configured to perform voltage conversion on the DC voltage so that the output power of the power conversion unit 20 meets the load demand.

[0068] Specifically, each single-stage power module 1 includes a corresponding rectifier unit 10 and a power conversion unit 20 , and each rectifier unit 10 is connected to its corresponding power conversion unit 20 .

[0069] The rectifier unit 10 may be a diode rectifier bridge (eg Figure 4-Figure 5 ) realizes the conversion from AC voltage to DC voltage. Such a configuration makes the structure of the power supply circuit simple and the cost is low. Of course, the rectifier unit 10 can also use other structures to realize the conversion from AC voltage to DC voltage, such as thyristor rectification, MOSFET rectification and other structures, and the present disclosure does not limit this.

[0070] The power conversion unit 20 is responsible for converting one form of electrical energy into another form to meet the specific requirements of different electronic devices and loads, and specifically controls the electrical energy by controlling the voltage.

[0071] In some embodiments, the output terminals of the power conversion units 20 are connected in parallel. Figure 3-Figure 5 As shown, that is, the output ends of the three single-stage power modules are connected in parallel, so that the three output voltages are the same, ensuring that the output powers of the three phases of the three-phase AC power system are the same.

[0072] Figure 6 A circuit diagram of another power supply circuit provided in an embodiment of the present disclosure.

[0073] refer to Figure 4-Figure 6 In some embodiments, the power conversion unit 20 includes at least one power conversion sub-unit 21.

[0074] Specifically, Figure 4 and Figure 5 A power conversion unit 20 includes only one power conversion subunit 21. Figure 6 A power conversion unit 20 includes a plurality of power conversion subunits 21. When a power conversion unit 20 includes a plurality of power conversion subunits 21, the input end of each power conversion subunit 21 is connected to the output end of the rectifier unit 10, and the output ends of each power conversion subunit 21 are connected in parallel. Increasing the number of power conversion subunits 21 in the power conversion unit 20 can increase the output power output by the single-stage power module 1. The specific number of power conversion subunits 21 included in each power conversion unit 20 can be determined according to the power required by the actual load.

[0075] For the convenience of description, the following embodiments are all based on Figure 4-Figure 6 Taking the first single-stage power module 1 (the top single-stage power module 1 in the figure) as an example, the structure of the power supply circuit is described in detail. It can be understood that the other two single-stage power modules 2 in the power supply circuit are Figure 4-Figure 6 The structure and working principle of the first single-stage power module 1 are exactly the same.

[0076] like Figure 4-Figure 6 As shown, in some embodiments, each of the power conversion subunits 21 includes an energy storage capacitor Cr, a switch tube Q1, a transformer, an inductor L1 and a diode D1.

[0077] Among them, the first end of the switch tube Q1 is connected to the first output end of the rectifier unit 10; the second end of the switch tube Q1 is connected to the first end of the first primary winding P of the transformer; the second end of the first primary winding P of the transformer is connected to the second output end of the rectifier unit 10; the first end of the first secondary winding S1 of the transformer is connected to the first end of the energy storage capacitor Cr, and the second end of the energy storage capacitor Cr is connected to the first end of the diode D1 and the first end of the inductor L1; the second end of the first secondary winding S1 of the transformer is connected to the second end of the diode D1.

[0078] Specifically, when the switch tube Q1 is turned on, the excitation current of the transformer rises linearly, the diode D1 is turned off, the energy storage capacitor Cr is discharged, and the current on the inductor L1 rises; when the switch tube Q1 is turned off, the diode D1 is turned on, the excitation current of the transformer charges the energy storage capacitor Cr, and the inductor L1 enters the freewheeling state, and the current decreases. Optionally, the diode D1 can also be replaced by a switch tube, and the present disclosure does not limit this.

[0079] The embodiment of the present disclosure controls the switching on and off of the switch tube Q1 to control the charging and discharging of the energy storage capacitor Cr and the inductor L1 respectively, thereby controlling the output power of the three power conversion units 20 to meet the load demand.

[0080] like Figure 4-Figure 6 As shown, in some embodiments, for each of the single-stage power modules 1, the power conversion unit 20 includes not only a storage capacitor Cr, a switch tube Q1, a transformer, an inductor L1 and a diode D1, but also a resistor RCS, an input capacitor C1 and an output capacitor Co1.

[0081] Among them, the first end of the input capacitor C1 is connected to the second output end of the rectifier unit 10; the second end of the input capacitor C1 is connected to the first end of the resistor RCS and the first end of the switch tube Q1; the second end of the resistor RCS is connected to the first output end of the rectifier unit 10; the first end of the output capacitor Co1 is connected to the second end of the inductor L1, and the second end of the output capacitor Co1 is connected to the second end of the first secondary winding S1 of the transformer.

[0082] Specifically, Figure 4-Figure 6 As shown, the input capacitor C1 and the output capacitor Co1 are used to filter the input or output. The resistor Rcs is arranged between the rectifier unit 10 and the input capacitor, and is used to detect the input current of the power conversion unit 20.

[0083] In some embodiments, when the power conversion unit 20 includes at least two power conversion sub-units 21 , the output ends of the at least two power conversion sub-units 21 are connected in parallel.

[0084] Specifically, refer to Figure 4-Figure 6 ,in, Figure 4 and Figure 5 A power conversion unit 20 includes only one power conversion subunit 21. Figure 6 A power conversion unit 20 includes a plurality of power conversion subunits 21. When a power conversion unit 20 includes a plurality of power conversion subunits 21, the input end of each power conversion subunit 21 is connected to the output end of the rectifier unit 10, and the output ends of each power conversion subunit 21 are connected in parallel. Increasing the number of power conversion subunits 21 in the power conversion unit 20 can increase the output power output by the single-stage power module 1. The specific number of power conversion subunits 21 included in each power conversion unit 20 can be determined according to the power required by the actual load.

[0085] For the three power conversion units 20 in the three single-stage power modules 1 , each power conversion unit 20 may include one or more power conversion sub-units 21 .

[0086] Optionally, the three power conversion units 20 in the three single-stage power modules 1 include the same number of power conversion sub-units 21 in each power conversion unit 20. This arrangement ensures that the output power of the three phases of the three-phase AC power system is the same.

[0087] The embodiment of the present disclosure can meet the application requirements of high power by providing a plurality of power conversion sub-units 21 in the power conversion unit 20 .

[0088] In some embodiments, for a case where a power conversion unit 20 includes multiple power conversion subunits 21, the power conversion unit 20 may include only one input capacitor C1 and one output capacitor Co1. The first end of the input capacitor C1 is connected to the second output end of the rectifier unit 10, and the second end of the input capacitor C1 is connected to the first end of the resistor Rcs and the first ends of the multiple switch tubes Q1 of the multiple power conversion subunits 21; the first end of the output capacitor Co1 is connected to the second ends of the multiple inductors L1 of the multiple power conversion subunits 21, and the second end of the output capacitor Co1 is connected to the second ends of the first secondary windings of the multiple transformers of the multiple power conversion subunits 21. In this configuration, one input capacitor is used to filter the inputs of the multiple power conversion subunits 21, and one output capacitor is used to filter the outputs of the multiple power conversion subunits 21, so that the circuit uses fewer components, has a simple structure, and saves costs.

[0089] In some embodiments, in the case where a power conversion unit 20 includes multiple power conversion subunits 21, the power conversion unit 20 may also include multiple input capacitors C1 and multiple output capacitors Co1 that are arranged one-to-one with the power conversion subunits 21. The first ends of the multiple input capacitors C1 are all connected to the second output end of the rectifier unit 10, the second ends of the multiple input capacitors C1 are connected to the first end of the resistor Rcs, and the second ends of the multiple input capacitors C1 are respectively connected to the first ends of the switch tubes Q1 corresponding to each power conversion subunit 21; the first ends of the multiple output capacitors Co1 are connected to the second ends of the inductors L1 corresponding to each power conversion subunit 21, and the second ends of the output capacitors Co1 are respectively connected to the second ends of the first secondary windings S1 of the transformer corresponding to each power conversion subunit 21. In this configuration, one input capacitor C1 is used to filter the input of one power conversion subunit 21, and one output capacitor Co1 is used to filter the output of one power conversion subunit 21, and the filtering effect is better.

[0090] Of course, for each of the single-stage power modules 1, the number of input capacitors C1 and output capacitors Co1 in the power conversion unit 20 may also be greater than 1 and less than the number of power conversion sub-units 21 in the power conversion unit 20. Specifically, according to the actual scenario, an input capacitor C1 can be used to filter the input of one or more power conversion sub-units 21, and an output capacitor Co1 can be used to filter the output of one or more power conversion sub-units 21. The present disclosure does not impose any restrictions on this.

[0091] Similar to the above-mentioned input capacitor C1 or output capacitor Co1, in some embodiments, the number of the resistors Rcs can be set in one-to-one correspondence with the number of power conversion subunits 21 in the power conversion unit 20, and each resistor Rcs is specifically configured to detect the input current of a corresponding power conversion subunit 21. Optionally, the number of the resistor Rcs can also be 1, which is specifically configured to detect the total input current of all power conversion subunits 21 in the power conversion unit 20, and no further details will be given.

[0092] It is understandable that if Figure 4-Figure 6 As shown, for the other two single-stage power modules 1, their structures and working principles are similar to those of the above-mentioned single-stage power module 1, and will not be repeated here.

[0093] like Figure 3-Figure 5As shown, in some embodiments, the power supply circuit includes not only three single-stage power modules 1, but also a power factor correction unit 30. The power factor correction unit 30 is connected to the power conversion unit 20, and the power factor correction unit 30 is configured to control the state of the switch tube based on the input parameters and output parameters of the power conversion unit 20 to correct the power factor of the power supply circuit.

[0094] Specifically, refer to Figure 3-Figure 5 As shown, the power factor correction unit 30 is capable of controlling the states of the three switch tubes (Q1, Q2 and Q3) in the three power conversion units 20 to control the charging and discharging of the energy storage capacitor Cr and the inductor (L1, L2 or L3) in each power conversion unit 20, thereby controlling the output power of the power conversion unit 20.

[0095] The input parameters include at least the input current and input voltage of each power conversion unit 20 , and the output parameters include at least the output current of each power conversion unit 20 .

[0096] like Figure 3-Figure 5 As shown, in some embodiments, the power factor correction unit 30 includes a voltage loop 31 , three current loops 32 corresponding to three single-stage power modules 1 , and three control units 33 .

[0097] Among them, the input end of the voltage loop 31 is connected to the output end of any power conversion unit 20 in the three single-stage power modules 1; the output end of the voltage loop 31 is respectively connected to the input ends of the three current loops 32; the input end of each current loop 32 is also connected to the first output end and the second output end of the rectifier unit 10 in the corresponding single-stage power module 1; the output ends of the three current loops 32 are respectively connected to the first ends of the three control units 33; the second ends of the three control units 33 are respectively connected to the control ends of the three switching tubes (Q1, Q2, Q3) in the three single-stage power modules 1.

[0098] Specifically, the voltage loop 31 acts on the output side of the power conversion unit 20 to control the output voltage of the power conversion unit 20 so that the output voltage of the power conversion unit 20 is stabilized at a preset value. The current loop 32 acts on the input side of the power conversion unit 20 to make the input current of the power conversion unit 20 change with the input voltage of the power conversion unit 20.

[0099] Although the power supply circuit provided by the present disclosure has a three-phase input, the three power conversion units 20 in the present disclosure are arranged in parallel, so the output voltages of the three power conversion units 20 are the same. Therefore, the present disclosure can use a voltage loop 31 to simultaneously control the switch tubes in the three power conversion units 20. Such an arrangement makes the power supply circuit provided by the present disclosure simpler. Of course, the power factor correction unit 30 can also use three voltage loops 31 to be connected to the output ends of the three power conversion units 20 respectively, and the present disclosure does not limit this.

[0100] Since the power supply circuit provided by the present disclosure is applied to a three-phase AC system, the three input currents of the three power conversion units 20 are 120° out of phase, and the present disclosure needs to track the input current of each phase separately. Therefore, the embodiment of the present disclosure sets three current loops 32 corresponding to the three power conversion units 20 respectively. Such a setting makes the power factor correction unit 30 more accurate in controlling the power conversion unit 20, so that the energy storage capacitor Cr and the inductor in the power conversion unit 20 can be charged and discharged more accurately according to the power required by the load. Of course, the power factor correction unit 30 can also use only one current loop 32. In this case, an additional conversion unit needs to be set to convert the phase of the current received or output by the current loop 32 to meet the phase difference corresponding to the different currents in the three phases to ensure accuracy. The present disclosure does not limit the number of current loops 32.

[0101] In some embodiments, the voltage loop 31 includes a voltage comparison unit and a voltage compensation network.

[0102] Among them, Figure 4-Figure 5 As shown, the voltage comparison unit is connected to the output end of any of the power conversion units 20 in the three single-stage power modules 1, and is configured to compare the output voltage V0 of the power conversion unit 20 with the reference voltage Vref to generate a first comparison result. The voltage compensation network is connected to the voltage comparison unit, and is configured to generate a first feedback voltage VEA according to the first comparison result.

[0103] Specifically, the reference voltage Vref is the voltage required by the load, and the reference voltage Vref can be directly obtained from an external input or determined based on an input instruction, which is not limited in the present disclosure. By comparing the output voltage Vo output by the power conversion unit 20 with the reference voltage Vref, and then compensating the output voltage Vo output by the power conversion unit 20 through a voltage compensation network, a first feedback voltage VEA is formed to keep the output voltage Vo output by the power conversion unit 20 stable.

[0104] like Figure 4-Figure 5As shown, the voltage comparison unit can be a comparator or other structures, and the present disclosure does not limit this. The voltage compensation network can be a compensation network such as an I-type compensation network, an SS compensation network, an LCC compensation network, etc., and can be specifically selected according to the requirements of system stability, response speed, cost, and design complexity, and the present disclosure does not limit this.

[0105] In some embodiments, for each current loop 32 corresponding to a single-stage power module 1 , the current loop 32 includes a reference current generating unit, a current comparing unit, and a current compensation network.

[0106] The reference current generating unit is connected to the output end of the voltage compensation network and the second output end of the rectifier unit 10 in the single-stage power module 1, and is configured to multiply the first feedback voltage VEA with the input voltage Vin_A of the power conversion unit 20 in the single-stage power module 1 to obtain the reference current Iref_A. The current comparison unit is connected to the reference current generating unit and the first output end of the rectifier unit 10, respectively, and is configured to compare the reference current Iref_A with the input current Iin_A of the power conversion unit 20 to generate a second comparison result. The current compensation network is connected to the current comparison unit, and is configured to generate a second feedback voltage VFB_A according to the second comparison result.

[0107] Specifically, Figure 4-Figure 5 As shown, the reference current generating unit can be a multiplier or other structures. The current comparison unit can be a comparator, or other structures such as an adder. The current compensation network can be an I-type current compensation network, a PP-type compensation network, an LCC-type compensation network, etc. The structure selection of the current compensation network depends on the specific application requirements, the characteristics of the system, and the required output characteristics (such as constant current or constant voltage output). Each structure has its specific advantages and limitations, and it needs to be selected according to the actual application scenario during design.

[0108] like Figure 4-Figure 5 As shown, in some embodiments, for the control unit 33 corresponding to each single-stage power module 1, the first end of the control unit 33 is connected to the current compensation network in the current loop 32 corresponding to the single-stage power module 1, and the second end of the control unit 33 is connected to the control end of the switch tube (Q1, Q2 or Q3) in the single-stage power module 1, and is configured to control the state of the switch tube (Q1, Q2 or Q3) based on the second feedback voltage generated by the current compensation network.

[0109] Specifically, the control unit 33 receives the second feedback voltage VFB_A sent by the corresponding current loop 32, calculates the on-time of the corresponding switch tube, and thus controls the off-time of the switch tube to control the charging and discharging of the energy storage capacitor Cr and the inductor L1, so that the power output by the power conversion unit 20 meets the load demand.

[0110] like Figure 4-Figure 5 As shown, in some embodiments, the power factor correction unit 30 also includes a second secondary winding S2 arranged on the transformer of each of the single-stage power modules 1; wherein the second secondary winding S2 arranged on each of the transformers is connected to a control unit 33 connected to the switch tube (Q1, Q2 or Q3) of the corresponding single-stage power module 1, and is configured to perform voltage detection on the transformer and output the voltage detection result; the control unit 33 is configured to control the state of the switch tube (Q1, Q2 or Q3) based on the voltage detection result and the second feedback voltage VFB_A.

[0111] Specifically, Figure 4-Figure 5 As shown, the power factor correction unit 30 is suitable for controlling the power supply circuit in the critical conduction mode. Among them, the second secondary winding S2 on the transformer of the single-stage power module 1 is connected to the control unit 33 connected to the switch tube of the corresponding single-stage power module 1, forming a valley detection circuit. After the control unit 33 detects the valley signal, it controls the corresponding switch tube to turn on. The embodiment of the present disclosure performs valley detection through an auxiliary winding. Of course, other structures can also be used for valley detection. The present disclosure does not limit the method of valley detection.

[0112] In some embodiments, the control unit 33 is further configured to receive the input voltage and output voltage of the power conversion unit 20, and the control unit 33 is specifically configured to control the state of the switch tube based on the input voltage and output voltage of the power conversion unit 20, the voltage detection result and the second feedback voltage. That is, in the embodiment of the present disclosure, compared with Figure 4-Figure 5 Corresponding to the embodiment, the embodiment of the present disclosure adds feedforward which can effectively improve the loop response speed.

[0113] Specifically, the feedforward is added, and the control unit 33 needs to sample the input voltage Vin and the output voltage Vo of the power conversion unit 20, so as to calculate the on-time feedforward value Ton_ff of the switch tube, and then calculate the on-time Ton of the switch tube Q1 through Ton_ffy and VFB. The calculation formula of Ton_ff is as follows:

[0114] Wherein, Nps represents the number of power conversion sub-units 21 included in one power conversion unit 20 .

[0115] Figure 7 1 is a working waveform of a power supply circuit provided by an embodiment of the present disclosure. Figure 7 As shown, i_Q1, i_Q2 and i_Q3 respectively represent the currents of three switch tubes in three single-stage power modules 1; PWM_Q1, PWM_Q2 and PWM_Q3 respectively represent the three control signals output by three control units 33 in three single-stage power modules 1. Figure 7 It can be seen that the currents of the three switching tubes in the three single-stage power conversion modules are the same in magnitude and have a phase difference of 120°.

[0116] Figure 8 The following is a control logic block diagram of a continuous conduction mode using a single power conversion unit 20 as an example provided in an embodiment of the present disclosure. Figure 8 and Figure 4-Figure 5 The difference between the single-stage power module 1 in FIG. 1 and FIG. 2 is only that the control unit 33 is different. In the continuous conduction mode, the control unit receives the constant wave triangular wave and the second feedback voltage VFB output by the current loop, and generates a control signal PWM to control the state of the switch tube.

[0117] The control unit 33 controls the N power conversion sub-units 21 in the power conversion unit 20 to operate in a continuous state, a critical continuous state, or a discontinuous state, with their phases staggered by 360 / N.

[0118] It should be noted that Figure 6 The corresponding power supply circuit does not show the power factor correction unit 30, but for Figure 6 The corresponding power conversion unit 20 includes a plurality of power conversion sub-units 21, and the specific configuration of the power factor correction unit 30 is the same as that described above. Figure 4-Figure 5 Similar to the corresponding embodiment, the power correction unit 30 still only includes one voltage loop 31, three current loops 32 and three control units 33, and the specific structure and working principle will not be repeated here.

[0119] The power circuit structure provided in the embodiment of the present disclosure is suitable for a three-phase AC system by connecting the three phases of the three-phase AC system to three single-stage power modules 1, and the outputs of the three single-stage power modules 1 are connected in parallel. Compared with the prior art that adopts a two-stage architecture to realize power conversion and transmission, the power circuit provided by the present disclosure has simple circuit connection, low cost, and strong scalability. Furthermore, the power conversion unit 20 in each single-stage power module 1 can also be connected in parallel with multiple power conversion sub-units 21 according to the load requirements to meet high-power applications. Furthermore, by adopting a voltage loop and a current loop, the power factor can be controlled.

[0120] In a second aspect, based on the same inventive concept, the embodiments of the present disclosure also provide a power factor correction method.

[0121] Fig. 9 A flowchart of a power factor correction method provided by an embodiment of the present disclosure. The method can be applied to the power supply circuit in any embodiment of the first aspect above, such as Fig. 9 As shown, the method specifically comprises the following steps:

[0122] S901 , collecting the output voltage Vo of any single-stage power module 1 , and comparing the output voltage Vo with a reference voltage Vref to generate a first comparison result.

[0123] S902 : Generate a first feedback voltage VEA according to the first comparison result.

[0124] S903 , multiply the first feedback voltage VEA by the input voltages Vin_A of the three single-stage power modules 1 respectively to obtain three reference currents Iref_A.

[0125] S904 , respectively compare the three reference currents Iref_A with the three input currents Iin_A of the three single-stage power modules 1 to generate three second comparison results.

[0126] S905 , generating three second feedback voltages VFB_A according to the three second comparison results respectively.

[0127] S906 , respectively controlling the states of the switch tubes in the three single-stage power modules 1 based on the three second feedback voltages VFB_A to correct the power factor of the power supply circuit.

[0128] Each control unit 33 in the power factor correction unit 30 in the power supply circuit controls the corresponding switch tube (Q1, Q2 or Q3) to turn on after detecting the respective valley signal. Specifically, the voltage loop 31 in the power factor correction unit 30 in the power supply circuit samples the output voltage Vo of any power conversion unit 20 and compares it with the reference voltage Vref, and then forms a first feedback voltage VEA through a voltage feedback compensation network; the first feedback voltage VEA is sent to the three single-stage power modules 1 respectively, and multiplied with the input voltage (Vin_A, Vin_B, Vin_C) of each power conversion unit 20 to obtain a reference current (Iref_A, Iref_B and Iref_C), and the input current (Iin_A, Iin_B, Iin_C) of each power conversion unit 20 is sampled and compared with the reference current (Iref_A, Iref_B and Iref_C), and a second feedback voltage (VFB_A, VFB_B and VFB_C) is formed through a current compensation network and sent to the respective control units 33, and each control unit 33 calculates the on-time of the switch tube, thereby controlling the corresponding switch tube to be turned off.

[0129] It can be understood that the specific details of the power factor correction method provided in the embodiment of the present disclosure can refer to the specific details of the power supply circuit device embodiment of the first aspect mentioned above, and will not be repeated here.

[0130] The solution provided by the present disclosure is applicable to a three-phase AC system by connecting three single-stage power modules 1 to the three phases of the three-phase AC system, and the outputs of the three single-stage power modules 1 are connected in parallel. Preferably, the power supply circuit provided by the present disclosure can adopt a three-phase three-wire AC input, and each of the three line voltages has one or more power conversion subunits 21, and multiple power conversion subunits 21 are output in parallel. Preferably, the power supply circuit provided by the present disclosure can adopt a three-phase four-wire AC input, and each of the three phase voltages has one or more power conversion subunits 21, and multiple power conversion subunits 21 are output in parallel. Preferably, the power factor correction method provided by the present disclosure is that all parallel modules (including three single-stage power modules 1 in parallel, and multiple power conversion subunits 21 in parallel in each single-stage power module 1) share a voltage loop 31, and each single-stage power module 1 has a current loop 32, and the switch tube voltage is controlled to be turned on when the switch tube voltage is at the valley position.

[0131] Compared with the prior art, the solution provided by the present disclosure has low cost, high efficiency, simple control, and easy expansion. In addition, the secondary current is continuous, and the current ripple flowing through the capacitor is small.

[0132] In a third aspect, an embodiment of the present disclosure further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method described in any one of the second aspects is implemented.

[0133] In a fourth aspect, an embodiment of the present disclosure further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program of the method described in any one of the second aspects above.

[0134] In a fifth aspect, an embodiment of the present disclosure further provides a computer program product, comprising a computer program / instructions, which, when executed by a processor, implement the steps of any one of the methods described in the second aspect above.

[0135] Those skilled in the art will appreciate that the embodiments of the present disclosure may be provided as methods, systems, or computer program products. Therefore, the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present disclosure may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0136] The present disclosure is described with reference to the flowchart and / or block diagram of the method, device (system), and computer program product according to the embodiment of the present disclosure. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the process and / or box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one process or multiple processes in the flowchart and / or one box or multiple boxes in the block diagram.

[0137] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0138] These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0139] The present disclosure uses specific embodiments to illustrate the principles and implementation methods of the present disclosure. The description of the above embodiments is only used to help understand the method of the present disclosure and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present disclosure, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present disclosure.

Claims

1. A power supply circuit suitable for three-phase electricity, characterized in that: The power supply circuit includes three single-stage power modules, the input ends of the three single-stage power modules are respectively configured to receive three line voltages / phase voltages of a three-phase alternating current system, and the output ends of the three single-stage power modules are arranged in parallel.

2. The power supply circuit according to claim 1, characterized in that: The input ends of the three single-stage power modules are respectively connected to the AB phase, BC phase, and AC phase of the three-phase alternating current system.

3. The power supply circuit according to claim 1, characterized in that: The input ends of the three single-stage power modules are respectively connected to the A phase and the neutral line, the B phase and the neutral line, and the C phase and the neutral line of the three-phase AC power system.

4. The power supply circuit according to claim 1, characterized in that: Each of the single-stage power modules includes a rectifier unit and a power conversion unit, wherein: The rectifying unit is configured to receive a line voltage / phase voltage of the three-phase AC power system and convert the line voltage / phase voltage into a DC voltage; The power conversion unit is connected to the output end of the rectifier unit and is configured to perform voltage conversion on the DC voltage so that the output power of the power conversion unit meets the demand of the load.

5. The power supply circuit according to claim 4, characterized in that: The output ends of the power conversion units are connected in parallel.

6. The power supply circuit according to any one of claims 4 or 5, characterized in that: The power conversion unit includes at least one power conversion sub-unit, each of which includes a storage capacitor, a switch tube, a transformer, an inductor and a diode; wherein, The first end of the switch tube is connected to the first output end of the rectifier unit; the second end of the switch tube is connected to the first end of the first primary winding of the transformer; The second end of the first primary winding of the transformer is connected to the second output end of the rectifier unit; The first end of the first secondary winding of the transformer is connected to the first end of the energy storage capacitor, and the second end of the energy storage capacitor is connected to the first end of the diode and the first end of the inductor; The second end of the first secondary winding of the transformer is connected to the second end of the diode.

7. The power supply circuit according to claim 6, characterized in that: When the power conversion unit includes at least two power conversion sub-units, the output ends of the at least two power conversion sub-units are connected in parallel.

8. The power supply circuit according to claim 6, characterized in that: The power supply circuit also includes a power factor correction unit, which is connected to the power conversion unit. The power factor correction unit is configured to control the state of the switching tube based on the input parameters and output parameters of the power conversion unit to correct the power factor of the power supply circuit.

9. The power supply circuit according to claim 8, characterized in that: The power factor correction unit includes a voltage loop, three current loops corresponding to three single-stage power modules, and three control units, wherein: The input end of the voltage loop is connected to the output end of any power conversion unit in the three single-stage power modules; The output end of the voltage loop is connected to the input ends of the three current loops respectively; The input end of each current loop is also connected to the first output end and the second output end of the rectifier unit in the corresponding single-stage power module; The output ends of the three current loops are respectively connected to the first ends of the three control units; The second ends of the three control units are respectively connected to the control ends of the three switch tubes in the three single-stage power modules.

10. The power supply circuit according to claim 9, characterized in that: The voltage loop comprises: a voltage comparison unit connected to the output end of any of the power conversion units in the three single-stage power modules, and configured to compare the output voltage of the power conversion unit with a reference voltage to generate a first comparison result; The voltage compensation network is connected to the voltage comparison unit and is configured to generate a first feedback voltage according to the first comparison result.

11. The power supply circuit according to claim 10, characterized in that: For the current loop corresponding to each single-stage power module, the current loop includes: a reference current generating unit connected to the output end of the voltage compensation network and the second output end of the rectifying unit in the single-stage power module, and configured to multiply the first feedback voltage by the input voltage of the power conversion unit in the single-stage power module to obtain a reference current; a current comparison unit, connected to the reference current generation unit and the first output terminal of the rectification unit respectively, and configured to compare the reference current with the input current of the power conversion unit to generate a second comparison result; The current compensation network is connected to the current comparison unit and is configured to generate a second feedback voltage according to the second comparison result.

12. The power supply circuit according to claim 11, characterized in that: For the control unit corresponding to each single-stage power module, the first end of the control unit is connected to the current compensation network in the current loop corresponding to the single-stage power module, and the second end of the control unit is connected to the control end of the switch tube in the single-stage power module, and is configured to control the state of the switch tube based on the second feedback voltage generated by the current compensation network.

13. The power supply circuit according to claim 12, characterized in that: For each of the single-stage power modules, The power conversion unit also includes a resistor, an input capacitor and an output capacitor; wherein, The first end of the input capacitor is connected to the second output end of the rectifier unit; The second end of the input capacitor is connected to the first end of the resistor and the first end of the switch tube; The second end of the resistor is connected to the first output end of the rectifier unit; The first end of the output capacitor is connected to the second end of the inductor, and the second end of the output capacitor is connected to the second end of the first secondary winding of the transformer.

14. The power supply circuit according to claim 13, characterized in that: The power factor correction unit further includes a second secondary winding arranged on the transformer of each single-stage power module; wherein, The second secondary winding of each transformer is connected to a control unit connected to a switch tube of a corresponding single-stage power module and is configured to perform voltage detection on the transformer and output a voltage detection result; The control unit is configured to control the state of the switch tube based on the voltage detection result and the second feedback voltage.

15. A method for power factor correction based on a power supply circuit, characterized in that: The method is applied to a power supply circuit according to any one of claims 1 to 14, and the method comprises: Collecting the output voltage of any single-stage power module, and comparing the output voltage with a reference voltage to generate a first comparison result; generating a first feedback voltage according to the first comparison result; Multiplying the first feedback voltage by the input voltages of the three single-stage power modules respectively to obtain three reference currents; Respectively comparing the three reference currents with the three input currents of the three single-stage power modules to generate three second comparison results; generating three second feedback voltages according to the three second comparison results respectively; The states of the switch tubes in the three single-stage power modules are controlled respectively based on the three second feedback voltages to correct the power factor of the power supply circuit.

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