Three-phase ACDC circuit

Abstract

The invention relates to a three-phase ACDC circuit which comprises a first controllable rectifier module, a first DCDC module, a second controllable rectifier module and a second DCDC module. The input ends of the first controllable rectifier module and the second controllable rectifier module are respectively connected to a first phase to a third phase of an alternating current power supply, and the output ends of the first controllable rectifier module and the second controllable rectifier module are respectively connected with the first DCDC module and the second DCDC module; the first controllable rectification module and the second controllable rectification module are controlled to be on and off in a power frequency period of the AC power supply to control the current phase of the second controllable rectification module so as to control the current phase of the first controllable rectification module and the second controllable rectification module; therefore, the three-phase power correction in the controllable rectification stage can be realized, and after the three-phase power correction, the lowest voltage is high, the voltage fluctuation amplitude is small, and the average current is small, so that the voltage gain range required to be adjusted by the rear-stage DCDC module is relatively narrow, and the parameter design and the efficiency improvement are facilitated.

Description

Technical Field

[0001] This invention relates to the field of alternating current-direct current (ACDC) conversion, and more specifically, to a three-phase ACDC circuit. Background Technology

[0002] Single-stage AC-DC circuits are widely researched and applied today due to their fewer power devices, lower cost, and higher efficiency. Common single-stage AC-DC circuits typically include an uncontrolled rectifier module and a DC-DC module, such as... Figure 1 The LLC circuit shown is as follows. The AC power from the mains is rectified by the uncontrolled rectifier module and then fed into the DC-DC module. The voltage waveform after uncontrolled rectification is as follows. Figure 2 The current in the subsequent circuit follows the voltage waveform, achieving power factor correction for the three-phase current. Figure 1 In the circuit shown, the voltage after uncontrolled rectification is zero at its minimum, the average current is large, and the voltage fluctuation amplitude is large. Therefore, the voltage gain range that needs to be adjusted in the subsequent DC-DC module is very wide, which brings great difficulties to the circuit parameter design. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a three-phase ACDC circuit that addresses the above-mentioned deficiencies of the prior art. The circuit has a minimum voltage greater than zero, small voltage fluctuation amplitude, and small average current. Therefore, the voltage gain range that the subsequent DC-DC module needs to adjust is narrower, which is beneficial to the parameter design and efficiency improvement of the subsequent DC-DC module.

[0004] The technical solution adopted by the present invention to solve its technical problem is: to construct a three-phase ACCDC circuit, including: a first controllable rectifier module, a first DCCDC module, a second controllable rectifier module, and a second DCCDC module; The first input terminal of the first controllable rectifier module is connected to the first phase of the AC power supply, the second input terminal is connected to the second phase of the AC power supply, the third input terminal is connected to the third phase of the AC power supply, the first output terminal is connected to the first input terminal of the first DC-DC module, the second output terminal is connected to the second input terminal of the first DC-DC module, the first output terminal of the first DC-DC module is connected to the first output terminal, and the second output terminal of the first DC-DC module is connected to the second output terminal. The first input terminal of the second controllable rectifier module is connected to the first phase of the AC power supply, the second input terminal is connected to the second phase of the AC power supply, the third input terminal is connected to the third phase of the AC power supply, the first output terminal is connected to the first input terminal of the second DC-DC module, the second output terminal is connected to the second input terminal of the second DC-DC module, the first output terminal of the second DC-DC module is connected to the first output terminal, and the second output terminal of the second DC-DC module is connected to the second output terminal. The first controllable rectifier module and the second controllable rectifier module are controlled to switch on and off in one power frequency cycle of the AC power supply to control the current phase of the first controllable rectifier module and the second controllable rectifier module, thereby realizing three-phase power correction.

[0005] In the three-phase AC-CDC circuit described in this invention, the first controllable rectifier module includes a first switching device, a second switching device, a third switching device, a fourth switching device, a fifth switching device, and a sixth switching device. The control terminals of the first switching device, the second switching device, the third switching device, the fourth switching device, the fifth switching device, and the sixth switching device respectively receive control signals; The first terminal of the first switching device, the first terminal of the third switching device, and the first terminal of the fifth switching device are connected to the first output terminal of the first controllable rectifier module; the second terminal of the second switching device, the second terminal of the fourth switching device, and the second terminal of the sixth switching device are connected to the second output terminal of the first controllable rectifier module; the second terminal of the first switching device and the first terminal of the second switching device are connected to the first phase of the AC power supply; the second terminal of the third switching device and the first terminal of the fourth switching device are connected to the second phase of the AC power supply; the second terminal of the fifth switching device and the first terminal of the sixth switching device are connected to the third phase of the AC power supply. The first controllable rectifier module is controlled to switch on and off in one power frequency cycle of the AC power supply to control the current phase of the first controllable rectifier module, including: the first switching device, the second switching device, the third switching device, the fourth switching device, the fifth switching device and the sixth switching device are respectively turned on or off based on the control signal so that the current of the first controllable rectifier module follows the phase of each phase of the AC power supply.

[0006] In the three-phase AC-DC circuit described in this invention, the first, second, third, fourth, fifth, and sixth switching devices are respectively turned on or off based on the control signal, so that the current of the first controllable rectifier module follows the phase of each phase of the AC power supply, including... In the first stage, the first switching device and the fourth switching device are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the first phase of the AC power supply. In the second stage, the first switching device and the fourth switching device are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the second phase of the AC power supply. In the third stage, the third and sixth switching devices are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the second phase of the AC power supply. In the fourth stage, the third and sixth switching devices are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the third phase of the AC power supply. In the fifth stage, the fifth switching device and the second switching device are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the third phase of the AC power supply. In the sixth stage, the fifth switching device and the second switching device are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the first phase of the AC power supply. The first stage, the second stage, the third stage, the fourth stage, the fifth stage, and the sixth stage constitute one power frequency cycle of the AC power supply.

[0007] In the three-phase AC-CDC circuit described in this invention, the second controllable rectifier module includes a seventh switching device, an eighth switching device, a ninth switching device, a tenth switching device, an eleventh switching device, and a twelfth switching device. The control terminals of the seventh, eighth, ninth, tenth, eleventh, and twelfth switching devices respectively receive control signals; The first terminals of the seventh, ninth, and eleventh switching devices are connected to the first output terminal of the second controllable rectifier module; the second terminals of the eighth, tenth, and twelfth switching devices are connected to the second output terminal of the second controllable rectifier module; the second terminal of the seventh and eighth switching devices are connected to the first phase of the AC power supply; the second terminal of the ninth and tenth switching devices are connected to the second phase of the AC power supply; and the second terminal of the eleventh and twelfth switching devices are connected to the third phase of the AC power supply. The second controllable rectifier module is controlled to switch on and off in one power frequency cycle of the AC power supply to control the current phase of the second controllable rectifier module, including: the seventh, eighth, ninth, tenth, eleventh and twelfth switching devices are respectively turned on or off based on the control signal to control the current of the second controllable rectifier module to follow the phase of each phase of the AC power supply.

[0008] In the three-phase AC-CDC circuit described in this invention, the seventh, eighth, ninth, tenth, eleventh, and twelfth switching devices are respectively turned on or off based on the control signal to control the current of the second controllable rectifier module to follow the phase of each phase of the AC power supply, including... In the first stage, the tenth and eleventh switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the third phase of the AC power supply. In the second stage, the seventh and twelfth switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the third phase of the AC power supply. In the third stage, the seventh and twelfth switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the first phase of the AC power supply. In the fourth stage, the ninth and eighth switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the first phase of the AC power supply. In the fifth stage, the ninth and eighth switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the second phase of the AC power supply. In the sixth stage, the tenth and eleventh switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the second phase of the AC power supply. The first stage, the second stage, the third stage, the fourth stage, the fifth stage, and the sixth stage constitute one power frequency cycle of the AC power supply.

[0009] In the three-phase AC-CDC circuit described in this invention, the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth switching devices each include a controllable thyristor; the first terminal of the switching device is the cathode of the controllable thyristor, and the second terminal of the switching device is the anode of the controllable thyristor; the control terminal of the switching device is the gate of the controllable thyristor.

[0010] In the three-phase AC-DC circuit described in this invention, the first switching device, the second switching device, the third switching device, the fourth switching device, the fifth switching device, the sixth switching device, the seventh switching device, the eighth switching device, the ninth switching device, the tenth switching device, the eleventh switching device, and the twelfth switching device respectively include a first MOSFET and a second MOSFET; The first terminal of the switching device is the source of the first MOS transistor, and the second terminal of the switching device is the source of the second MOS transistor; the control terminal of the switching device is the gate of the first MOS transistor and the gate of the second MOS transistor; the drain of the first MOS transistor is connected to the drain of the second MOS transistor.

[0011] In the three-phase AC-CDC circuit described in this invention, the first switching device, the second switching device, the third switching device, the fourth switching device, the fifth switching device, the sixth switching device, the seventh switching device, the eighth switching device, the ninth switching device, the tenth switching device, the eleventh switching device, and the twelfth switching device respectively include diodes and MOSFETs; The first terminal of the switching device is the cathode of the diode, and the second terminal of the switching device is the source of the MOS transistor; the control terminal of the switching device is the gate of the MOS transistor; the anode of the diode is connected to the drain of the MOS transistor.

[0012] In the three-phase ACDC circuit described in this invention, the first DCDC module includes a half-bridge LLC module, a bidirectional DCDC conversion module, a single-ended primary inductor conversion module, or a phase-shifting full-bridge module.

[0013] In the three-phase ACDC circuit described in this invention, the second DCDC module includes a half-bridge LLC module, a bidirectional DCDC conversion module, a single-ended primary inductor conversion module, or a phase-shifting full-bridge module.

[0014] The three-phase AC-CDC circuit of the present invention includes: a first controllable rectifier module, a first DC-CDC module, a second controllable rectifier module, and a second DC-CDC module. The input terminals of the first controllable rectifier module and the second controllable rectifier module are respectively connected to the first to third phases of the AC power supply, and the output terminals are respectively connected to the first DC-CDC module and the second DC-CDC module. The first controllable rectifier module and the second controllable rectifier module are controlled to switch on and off in one power frequency cycle of the AC power supply to control the current phase of the first controllable rectifier module and the second controllable rectifier module. This enables three-phase power correction during the controllable rectification stage. After three-phase power correction, the minimum voltage is high, the voltage fluctuation amplitude is small, and the average current is small. Therefore, the voltage gain range that the subsequent DC-CDC module needs to adjust is narrower, which is beneficial to the parameter design and efficiency improvement of the subsequent DC-CDC module. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a circuit diagram of an existing LLC circuit; Figure 2 yes Figure 1 The voltage waveform diagram of the LLC circuit shown; Figure 3 This is a schematic block diagram of a preferred embodiment of the three-phase AC-CDC circuit of the present invention; Figure 4 This is a circuit diagram of a preferred embodiment of the three-phase AC-CDC circuit of the present invention; Figures 5A-5D This is a circuit diagram of a preferred embodiment of the DC-DC module of the three-phase AC-DC circuit of the present invention; Figures 6A-6B This is a circuit diagram of a preferred embodiment of the controllable rectifier module of the three-phase ACDC circuit of the present invention; Figure 7 yes Figure 4 The waveforms of the current, voltage, and control signals in the three-phase AC-DC circuit are shown below. Figures 8A-8F yes Figure 4 The diagram shows the current path of a three-phase AC-CDC circuit at different stages. Figure 9 yes Figure 4 The simulation waveform diagram of the three-phase AC-CDC circuit is shown below; Figure 10 yes Figure 4 The diagram shows the simulated waveforms of the three-phase current and voltage of the three-phase AC-CDC circuit. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] Figure 3 This is a schematic block diagram of a preferred embodiment of the three-phase AC-CDC circuit of the present invention. Figure 3 As shown, the three-phase ACCDC circuit of the present invention includes: a first controllable rectifier module 100, a first DC-DC module 300, a second controllable rectifier module 200, and a second DC-DC module 400. The first controllable rectifier module 100 has its first input terminal connected to phase A of the AC power supply, its second input terminal connected to phase B of the AC power supply, its third input terminal connected to phase C of the AC power supply, its first output terminal connected to the first input terminal of the first DC-DC module 300, its second output terminal connected to the second input terminal of the first DC-DC module 300, its first output terminal connected to the first output terminal, and its second output terminal connected to the second output terminal. Similarly, the second controllable rectifier module 200 has its first input terminal connected to phase A of the AC power supply, its second input terminal connected to phase B of the AC power supply, its third input terminal connected to phase C of the AC power supply, its first output terminal connected to the first input terminal of the second DC-DC module 400, its second output terminal connected to the second input terminal of the second DC-DC module 400, its first output terminal connected to the first output terminal, and its second output terminal connected to the second output terminal. The first controllable rectifier module 100 and the second controllable rectifier module 200 are controlled to switch on and off in one power frequency cycle of the AC power supply to control the current phase of the first controllable rectifier module 100 and the second controllable rectifier module 200, thereby realizing three-phase power correction.

[0018] The three-phase AC-CDC circuit of the present invention includes: a first controllable rectifier module, a first DC-CDC module, a second controllable rectifier module, and a second DC-CDC module. The input terminals of the first controllable rectifier module and the second controllable rectifier module are respectively connected to the first to third phases of the AC power supply, and the output terminals are respectively connected to the first DC-CDC module and the second DC-CDC module. The first controllable rectifier module and the second controllable rectifier module are controlled to switch on and off in one power frequency cycle of the AC power supply to control the current phase of the first controllable rectifier module and the second controllable rectifier module. This enables three-phase power correction during the controllable rectification stage. After three-phase power correction, the minimum voltage is high, the voltage fluctuation amplitude is small, and the average current is small. Therefore, the voltage gain range that the subsequent DC-CDC module needs to adjust is narrower, which is beneficial to the parameter design and efficiency improvement of the subsequent DC-CDC module.

[0019] Figure 4 This is a circuit diagram of a preferred embodiment of the three-phase AC-CDC circuit of the present invention. (In conjunction with...) Figures 3-4 As can be seen, the three-phase ACDC circuit of the present invention includes: a first controllable rectifier module 100, a first DC-DC module 300, a second controllable rectifier module 200, and a second DC-DC module 400. The first controllable rectifier module 100 has its first input terminal connected to phase A of the AC power supply, its second input terminal connected to phase B of the AC power supply, its third input terminal connected to phase C of the AC power supply, its first output terminal connected to the first input terminal of the first DC-DC module 300, its second output terminal connected to the second input terminal of the first DC-DC module 300, its first output terminal connected to the first output terminal, and its second output terminal connected to the second output terminal. Similarly, the second controllable rectifier module 200 has its first input terminal connected to phase A of the AC power supply, its second input terminal connected to phase B of the AC power supply, its third input terminal connected to phase C of the AC power supply, its first output terminal connected to the first input terminal of the second DC-DC module 400, its second output terminal connected to the second input terminal of the second DC-DC module 400, its first output terminal connected to the first output terminal, and its second output terminal connected to the second output terminal.

[0020] Further as Figure 4As shown, the first controllable rectifier module 100 includes a first switching device Q1, a second switching device Q2, a third switching device Q3, a fourth switching device Q4, a fifth switching device Q5, and a sixth switching device Q6; the second controllable rectifier module 200 includes a seventh switching device Q7, an eighth switching device Q8, a ninth switching device Q9, a tenth switching device Q10, an eleventh switching device Q11, and a twelfth switching device Q12. The first DC-DC module 300 and the second DC-DC module 400 can employ any known DC-DC module in the art, for example... Figures 5A-5D The diagram shows a half-bridge LLC module, a bidirectional DC-DC converter module, a single-ended primary inductor converter module, or a phase-shifted full-bridge module. Figure 4 In the preferred embodiment shown, the first DC-DC module 300 and the second DC-DC module 400 are both phase-shifted full-bridge modules. The first DC-DC module 300 includes a switching rectifier bridge QM1~QM4, a resonant capacitor Cr1 and a resonant inductor Lr1, a transformer T1 and diode rectifier bridges D1~D4; the second DC-DC module 400 includes a switching rectifier bridge QM5~QM8, a resonant capacitor Cr2 and a resonant inductor Lr2, a transformer T2 and diode rectifier bridges D5~D8.

[0021] like Figure 4 As shown, the control terminals of the first switching device Q1, the second switching device Q2, the third switching device Q3, the fourth switching device Q4, the fifth switching device Q5, and the sixth switching device Q6 respectively receive control signals; the first terminal of the first switching device Q1, the first terminal of the third switching device Q3, and the first terminal of the fifth switching device Q5 are connected to the first output terminal of the first controllable rectifier module 100; the second terminal of the second switching device Q2, the second terminal of the fourth switching device Q4, and the second terminal of the sixth switching device Q6 are connected to the second output terminal of the first controllable rectifier module 100; the first terminal of the first switching device Q1... The second terminal of the second switching device Q2 and the first terminal of the third switching device Q3 are connected to phase A of the AC power supply; the second terminal of the third switching device Q3 and the first terminal of the fourth switching device Q4 are connected to phase B of the AC power supply; the second terminal of the fifth switching device Q5 and the first terminal of the sixth switching device Q6 are connected to phase C of the AC power supply; the first switching device Q1, the second switching device Q2, the third switching device Q3, the fourth switching device Q4, the fifth switching device Q5 and the sixth switching device Q6 are respectively turned on or off based on the control signal so that the current of the first controllable rectifier module 100 follows the phase of each phase of the AC power supply.

[0022] The second controllable rectifier module 200 includes a seventh switch device Q7, an eighth switch device Q8, a ninth switch device Q9, a tenth switch device Q10, an eleventh switch device Q11, and a twelfth switch device Q12. The control terminals of the seventh switch device Q7, the eighth switch device Q8, the ninth switch device Q9, the tenth switch device Q10, the eleventh switch device Q11, and the twelfth switch device Q12 respectively receive control signals. The first terminals of the seventh switch device Q7, the ninth switch device Q9, and the eleventh switch device Q11 are connected to the first output terminal of the second controllable rectifier module 200. The second terminals of the eighth switch device Q8, the tenth switch device Q10, and the twelfth switch device Q12 are connected to the first output terminal of the second controllable rectifier module 200. The second terminal of the second controllable rectifier module 200 is connected to the second output terminal; the second terminal of the seventh switch Q7 and the first terminal of the eighth switch Q8 are connected to phase A of the AC power supply; the second terminal of the ninth switch Q9 and the first terminal of the tenth switch Q10 are connected to phase B of the AC power supply; the second terminal of the eleventh switch Q11 and the first terminal of the twelfth switch Q12 are connected to phase C of the AC power supply; the seventh switch Q7, the eighth switch Q8, the ninth switch Q9, the tenth switch Q10, the eleventh switch Q11 and the twelfth switch Q12 are respectively turned on or off based on the control signal so that the current of the second controllable rectifier module 200 follows the phase of each phase of the AC power supply.

[0023] exist Figure 4 In the preferred embodiment shown, the first switching device Q1, the second switching device Q2, the third switching device Q3, the fourth switching device Q4, the fifth switching device Q5, the sixth switching device Q6, the seventh switching device Q7, the eighth switching device Q8, the ninth switching device Q9, the tenth switching device Q10, the eleventh switching device Q11, and the twelfth switching device Q12 each include a controllable thyristor; the first terminal of the switching device is the cathode of the controllable thyristor, and the second terminal of the switching device is the anode of the controllable thyristor; the control terminal of the switching device is the gate of the controllable thyristor.

[0024] In other preferred embodiments of the present invention, the first switching device Q1, the second switching device Q2, the third switching device Q3, the fourth switching device Q4, the fifth switching device Q5, the sixth switching device Q6, the seventh switching device Q7, the eighth switching device Q8, the ninth switching device Q9, the tenth switching device Q10, the eleventh switching device Q11, and the twelfth switching device Q12 may also be other switching devices, as long as they are controllable and bidirectionally cut-off switching devices.

[0025] Figures 6A-6B This is a circuit diagram of a preferred embodiment of the controllable rectifier module of the three-phase ACDC circuit of the present invention. Figure 6A As shown, the first switching device, the second switching device Q2, the third switching device Q3, the fourth switching device Q4, the fifth switching device Q5, the sixth switching device Q6, the seventh switching device Q7, the eighth switching device Q8, the ninth switching device Q9, the tenth switching device Q10, the eleventh switching device Q11, and the twelfth switching device Q12 each include a diode DQ1 and a MOSFET QQ1; the first terminal of each switching device is the cathode of the diode DQ1, and the second terminal of each switching device is the source of the MOSFET QQ1; the control terminal of each switching device is the gate of the MOSFET QQ1; the anode of the diode DQ1 is connected to the drain of the MOSFET QQ1. Figure 6B As shown, the first switching device, the second switching device Q2, the third switching device Q3, the fourth switching device Q4, the fifth switching device Q5, the sixth switching device Q6, the seventh switching device Q7, the eighth switching device Q8, the ninth switching device Q9, the tenth switching device Q10, the eleventh switching device Q11, and the twelfth switching device Q12 each include a MOSFET Q1 and a MOSFET Q2; the first terminal of the switching device is the source of the MOSFET Q1, and the second terminal of the switching device is the source of the MOSFET Q2; the control terminal of the switching device is the gate of the MOSFET Q1 and the gate of the MOSFET Q2; the drain of the MOSFET Q1 is connected to the drain of the MOSFET Q2.

[0026] In this invention, in the first stage, the first switching device Q1 and the fourth switching device Q4 are turned on to control the current of the first DC-DC module, thereby making the current of the first controllable rectifier module 100 follow the phase of phase A of the AC power supply. The tenth switching device Q10 and the eleventh switching device Q11 are turned on to control the current of the second DC-DC module, thereby making the current of the second controllable rectifier module 200 follow the phase of phase C of the AC power supply. In the second stage, the first switching device Q1 and the fourth switching device Q4 are turned on to control the current of the first DC-DC module, thereby making the current of the first controllable rectifier module 100 follow the phase of phase B of the AC power supply. The seventh switching device... Device Q7 and the twelfth switch Q12 are turned on to control the current of the second DC-DC module, thereby making the current of the second controllable rectifier module 200 follow the phase of phase C of the AC power supply; in the third stage, the third switch Q3 and the sixth switch Q6 are turned on to control the current of the first DC-DC module, thereby making the current of the first controllable rectifier module 100 follow the phase of phase B of the AC power supply; the seventh switch Q7 and the twelfth switch Q12 are turned on to control the current of the second DC-DC module, thereby making the current of the second controllable rectifier module 200 follow the phase of phase A of the AC power supply; in the fourth stage, the third switch Q3 and the sixth switch Q12 are turned on to control the current of the second DC-DC module, thereby making the current of the second controllable rectifier module 200 follow the phase of phase A of the AC power supply; in the fourth stage, the third switch Q7 and the twelfth switch Q12 are turned on to control the current of the second DC-DC module, thereby making the current of the second controllable rectifier module 200 follow the phase of phase A of the AC power supply; in the fourth stage, the third switch Q7 and the twelfth switch Q12 are turned on to control the current of the second DC-DC module, thereby making the current of the second controllable rectifier module 200 follow the phase of phase A of the AC power supply; in the fifth stage, the third switch Q7 and the twelfth switch Q12 are turned on to control the current of the second DC-DC module, thereby making the current of the second controllable rectifier module 200 follow the phase of phase A of the AC power supply; in the sixth ... Device Q6 is turned on to control the current of the first DC-DC module, thereby making the current of the first controllable rectifier module 100 follow the phase of phase C of the AC power supply. The ninth switch Q9 and the eighth switch Q8 are turned on to control the current of the second DC-DC module, thereby making the current of the second controllable rectifier module 200 follow the phase of phase A of the AC power supply. In the fifth stage, the fifth switch Q5 and the second switch Q2 are turned on to control the current of the first DC-DC module, thereby making the current of the first controllable rectifier module 100 follow the phase of phase C of the AC power supply. The ninth switch Q9 and the eighth switch Q8 are turned on to control the current of the second DC-DC module. The current of the second controllable rectifier module 200 follows the phase of phase B of the AC power supply. In the sixth stage, the fifth switch Q5 and the second switch Q2 are turned on to control the current of the first DC-DC module, thereby making the current of the first controllable rectifier module 100 follow the phase of phase A of the AC power supply. The tenth switch Q10 and the eleventh switch Q11 are turned on to control the current of the second DC-DC module, thereby making the current of the second controllable rectifier module 200 follow the phase of phase B of the AC power supply. The first stage, the second stage, the third stage, the fourth stage, the fifth stage, and the sixth stage constitute one power frequency cycle of the AC power supply.

[0027] Figure 7 yes Figure 4 The diagram shows the current, voltage, and control signal waveforms of the three-phase AC / DC circuit. Figures 8A-8F yes Figure 4 The diagram shows the current path of a three-phase AC-CDC circuit at different stages. Figure 9 yes Figure 4 The following is a simulation waveform diagram of a three-phase AC-CDC circuit. Figure 7 , Figures 8A-8F as well as Figure 9 right Figure 4 The principle and control process of the three-phase AC-CDC circuit shown are explained below.

[0028] Figure 4 The current path of the three-phase AC-CDC circuit shown in the first stage t1 is as follows: Figure 8A As shown, the switching devices Q1 and Q4 of the first controllable rectifier module 100 are turned on, and current flows from phase A to phase B, controlling the current of the first DC-DC module 300 so that the current I1 of the first controllable rectifier module 100 follows the phase of phase A; the switching devices Q11 and Q10 of the second controllable rectifier module 200 are turned on, and current flows from phase C to phase B, controlling the current of the second DC-DC module 400 so that the current I2 of the second controllable rectifier module 200 follows the phase of phase C; since the sum of the three-phase currents is 0, the current of phase B is equal to the sum of the current of phase A and the inverse of the current of phase C, thus achieving three-phase power factor correction in this stage. Those skilled in the art will understand that this is because the rectifier module operates at power frequency, and the current magnitude and phase are determined by the control of the subsequent DC-DC module. The switching of the rectifier module can change the current of the subsequent DC-DC module, thereby achieving control over the current magnitude and phase of the rectifier module. The control process is known to those skilled in the art and will not be elaborated further here. Figure 4 The current path of the three-phase AC-CDC circuit shown in the second stage t2 is as follows: Figure 8B As shown, the switching devices Q1 and Q4 of the first controllable rectifier module 100 are turned on, and the current flows from phase A to phase B, controlling the current of the first DC-DC module 300 so that the current I1 of the first controllable rectifier module 100 follows the phase of phase B; the switching devices Q7 and Q12 of the second controllable rectifier module 200 are turned on, and the current flows from phase A to phase C, controlling the current of the second DC-DC module 400 so that the current I2 of the second controllable rectifier module 200 follows the phase of phase C; since the sum of the three-phase currents is 0, the current of phase A is equal to the sum of the current of phase B and the inverse of the current of phase C, thus achieving three-phase power factor correction in this stage.

[0029] Figure 4The current path of the three-phase AC-CDC circuit shown is as follows during the third stage t3 of operation: Figure 8C As shown, the switching devices Q3 and Q6 of the first controllable rectifier module 100 are turned on, and the current flows from phase B to phase C, controlling the current of the first DC-DC module 300 so that the current I1 of the first controllable rectifier module 100 follows the phase of phase B; the switching devices Q7 and Q12 of the second controllable rectifier module 200 are turned on, and the current flows from phase A to phase C, controlling the current of the second DC-DC module 400 so that the current I2 of the second controllable rectifier module 200 follows the phase of phase A; since the sum of the three-phase currents is 0, the current of phase C is equal to the sum of the current of phase A and the inverse of the current of phase B, thus achieving three-phase power factor correction in this stage.

[0030] Figure 4 The current path of the three-phase AC-CDC circuit shown is as follows during the fourth stage t4 of operation: Figure 8D As shown, the switching devices Q3 and Q6 of the first controllable rectifier module 100 are turned on, and the current flows from phase B to phase C, controlling the current of the first DC-DC module 300 so that the current I1 of the first controllable rectifier module 100 follows the phase of phase C; the switching devices Q9 and Q8 of the second controllable rectifier module 200 are turned on, and the current flows from phase B to phase A, controlling the current of the second DC-DC module 400 so that the current I2 of the second controllable rectifier module 200 follows the phase of phase A; since the sum of the three-phase currents is 0, the phase B current is equal to the phase A current plus the inverse of the phase C current, thus achieving three-phase power factor correction in this stage.

[0031] Figure 4 The current path of the three-phase AC-CDC circuit shown is as follows during the fifth stage t5 operation: Figure 8E As shown, the switching devices Q5 and Q2 of the first controllable rectifier module 100 are turned on, and the current flows from phase C to phase A, controlling the current of the first DC-DC module 300 so that the current I1 of the first controllable rectifier module 100 follows the phase of phase C; the switching devices Q9 and Q8 of the second controllable rectifier module 200 are turned on, and the current flows from phase B to phase A, controlling the current of the second DC-DC module 400 so that the current I2 of the second controllable rectifier module 200 follows the phase of phase B; since the sum of the three-phase currents is 0, the current of phase A is equal to the sum of the current of phase B and the inverse of the current of phase C, thus achieving three-phase power factor correction in this stage.

[0032] Figure 4 The current path of the three-phase AC-CDC circuit shown is as follows during the sixth stage t6 of operation: Figure 8FAs shown, the switching devices Q5 and Q2 of the first controllable rectifier module 100 are turned on, and the current flows from phase C to phase A, controlling the current of the first DC-DC module 300 so that the current I1 of the first controllable rectifier module 100 follows the phase of phase A; the switching devices Q11 and Q10 of the second controllable rectifier module 200 are turned on, and the current flows from phase C to phase B, controlling the current of the second DC-DC module 400 so that the current I2 of the second controllable rectifier module 200 follows the phase of phase B; since the sum of the three-phase currents is 0, the current of phase C is equal to the sum of the current of phase A and the inverse of the current of phase B, thus achieving three-phase power factor correction in this stage.

[0033] The first stage (t1) to the sixth stage (t6) constitutes a complete AC voltage power frequency cycle. Through the above working process, full-cycle voltage and current phase tracking is achieved. The theoretically calculated average voltage after rectification by this rectifier circuit is... Figure 2 The voltage of the steamed bun is 1.299 times that of the medium-sized steamed bun; the simulation results are as follows. Figure 9 As shown, taking a three-phase phase voltage of 220Vac as an example, Figure 1 The average value after rectification in the previous scheme is 343V, while the average value of U1 and U2 after rectification in this invention is 445.6V, a ratio of 1.299, consistent with the theoretical calculation. The above control method can achieve phase following of current and voltage in each phase, as demonstrated by simulation results. Figure 10 The display shows that the subsequent DC-DC circuit has only two channels, one less than the traditional circuit. This invention, by controlling the power frequency rectifier switch, increases the average voltage by 1.299 times compared to the traditional uncontrolled rectifier scheme, significantly reducing voltage fluctuations. Furthermore, the fact that the subsequent DC-DC circuit has only two channels, one less than the traditional circuit, greatly aids in the parameter design and efficiency improvement of the subsequent DC-DC circuit. The solution is novel and has significant application prospects.

[0034] Although the present invention has been described through specific embodiments, those skilled in the art will understand that various modifications and equivalent substitutions can be made to the invention without departing from its scope. Furthermore, various modifications can be made to the invention for specific situations or materials without departing from its scope. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all embodiments falling within the scope of the claims.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-phase AC-DC circuit, characterized by The application relates to a three-phase power correction device. The application relates to a three-phase power correction device. The application relates to a three-phase power correction device. The application relates to a three-phase power correction device. The application relates to a three-phase power correction device.

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The application relates to a three-phase power correction device. The application relates to a three-phase power correction device. The application 3. The three-phase AC-DC circuit of claim 2, wherein, The first, second, third, fourth, fifth, and sixth switching devices are respectively turned on or off based on the control signal so that the current of the first controllable rectifier module follows the phase of each phase of the AC power supply, including... In the first stage, the first switching device and the fourth switching device are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the first phase of the AC power supply. In the second stage, the first switching device and the fourth switching device are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the second phase of the AC power supply. In the third stage, the third and sixth switching devices are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the second phase of the AC power supply. In the fourth stage, the third and sixth switching devices are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the third phase of the AC power supply. In the fifth stage, the fifth switching device and the second switching device are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the third phase of the AC power supply. In the sixth stage, the fifth switching device and the second switching device are turned on to control the current of the first DC-DC module, thereby enabling the current of the first controllable rectifier module to follow the phase of the first phase of the AC power supply. The first stage, the second stage, the third stage, the fourth stage, the fifth stage, and the sixth stage constitute one power frequency cycle of the AC power supply.

4. A three-phase AC-DC circuit according to claim 2 or 3, characterized in that, The second controllable rectifier module includes a seventh switching device, an eighth switching device, a ninth switching device, a tenth switching device, an eleventh switching device, and a twelfth switching device; The control terminals of the seventh, eighth, ninth, tenth, eleventh, and twelfth switching devices respectively receive control signals; The first terminals of the seventh, ninth, and eleventh switching devices are connected to the first output terminal of the second controllable rectifier module; the second terminals of the eighth, tenth, and twelfth switching devices are connected to the second output terminal of the second controllable rectifier module; the second terminal of the seventh and eighth switching devices are connected to the first phase of the AC power supply; the second terminal of the ninth and tenth switching devices are connected to the second phase of the AC power supply; and the second terminal of the eleventh and twelfth switching devices are connected to the third phase of the AC power supply. The second controllable rectifier module is controlled to switch on and off in one power frequency cycle of the AC power supply to control the current phase of the second controllable rectifier module, including: the seventh, eighth, ninth, tenth, eleventh and twelfth switching devices are respectively turned on or off based on the control signal to control the current of the second controllable rectifier module to follow the phase of each phase of the AC power supply.

5. The three-phase AC-DC circuit of claim 4, wherein, The seventh, eighth, ninth, tenth, eleventh, and twelfth switching devices are respectively turned on or off based on the control signal to control the current of the second controllable rectifier module to follow the phase of each phase of the AC power supply, including: In the first stage, the tenth and eleventh switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the third phase of the AC power supply. In the second stage, the seventh and twelfth switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the third phase of the AC power supply. In the third stage, the seventh and twelfth switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the first phase of the AC power supply. In the fourth stage, the ninth and eighth switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the first phase of the AC power supply. In the fifth stage, the ninth and eighth switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the second phase of the AC power supply. In the sixth stage, the tenth and eleventh switching devices are turned on to control the current of the second DC-DC module, thereby enabling the current of the second controllable rectifier module to follow the phase of the second phase of the AC power supply. The first stage, the second stage, the third stage, the fourth stage, the fifth stage, and the sixth stage constitute one power frequency cycle of the AC power supply.

6. The three-phase AC-DC circuit of claim 5, wherein, The first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth switching devices each include a controllable thyristor; the first terminal of the switching device is the cathode of the controllable thyristor, and the second terminal of the switching device is the anode of the controllable thyristor; the control terminal of the switching device is the gate of the controllable thyristor.

7. The three-phase AC-DC circuit of claim 5, wherein, The first switching device, the second switching device, the third switching device, the fourth switching device, the fifth switching device, the sixth switching device, the seventh switching device, the eighth switching device, the ninth switching device, the tenth switching device, the eleventh switching device, and the twelfth switching device each include a first MOSFET and a second MOSFET; The first terminal of the switching device is the source of the first MOS transistor, and the second terminal of the switching device is the source of the second MOS transistor; the control terminal of the switching device is the gate of the first MOS transistor and the gate of the second MOS transistor; the drain of the first MOS transistor is connected to the drain of the second MOS transistor.

8. The three-phase AC-DC circuit of claim 5, wherein, The first switching device, the second switching device, the third switching device, the fourth switching device, the fifth switching device, the sixth switching device, the seventh switching device, the eighth switching device, the ninth switching device, the tenth switching device, the eleventh switching device, and the twelfth switching device each include a diode and a MOSFET. The first terminal of the switching device is the cathode of the diode, and the second terminal of the switching device is the source of the MOS transistor; the control terminal of the switching device is the gate of the MOS transistor; the anode of the diode is connected to the drain of the MOS transistor.

9. The three-phase AC-DC circuit of claim 5, wherein, The first DC-DC module includes a half-bridge LLC module, a bidirectional DC-DC converter module, a single-ended primary inductor converter module, or a phase-shifting full-bridge module.

10. The three-phase AC-DC circuit of claim 5, wherein, The second DC-DC module includes a half-bridge LLC module, a bidirectional DC-DC converter module, a single-ended primary inductor converter module, or a phase-shifting full-bridge module.

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