Hydrogen production power supply soft start method and system

Abstract

The application discloses a hydrogen production power supply soft starting method and system. The method comprises the following steps: closing a line two switch K2 and opening a line one switch K1; during the working process of the line two, a rectifier converter unit is started in a phase control mode, a phase control angle of the rectifier converter unit is gradually increased, an AC / DC converter unit works in a boosting state, the phase control angle of the rectifier converter unit is gradually increased until the output bus voltage of the AC / DC converter unit reaches a preset voltage; and the system comprises a first switch, the line one switch, the line two switch, the rectifier converter unit, the AC / DC converter unit and an electrolytic cell. The hydrogen production power supply soft starting method and system adopt a first-stage hydrogen production AC / DC topology to realize the soft starting of an output bus, meet the demand of the load starting of the electrolytic cell, maintain the power quality characteristics of the AC / DC+DC / DC two-stage topology, and are simple and low in cost.

Description

Technical Field

[0001] This application relates to the field of hydrogen production technology, and in particular to a soft-start method and system for hydrogen production power supply. Background Technology

[0002] Against the backdrop of the need for carbon peaking and carbon neutrality, carbon conservation and emission reduction have become a consensus in the energy industry. In addition to wind power and photovoltaics, hydrogen energy has also become a major area of ​​demand for new energy sources. In 2020, my country's hydrogen production reached 25 million tons, accounting for more than 40% of global production, making it the world's largest hydrogen producer, and hydrogen production has steadily increased over the past five years. Hydrogen production through water electrolysis is favored due to its environmental friendliness and large reserves.

[0003] A hydrogen production system mainly consists of a transformer, a hydrogen production power supply, and an electrolyzer. The hydrogen production power supplies used in large quantities on the market are primarily thyristor power supplies, whose main advantage is low cost, but their power quality characteristics are poor, and they cause significant harmonic pollution to the power grid.

[0004] To address the issues with thyristor rectifier power supplies, new energy vehicle control manufacturers have introduced IGBT rectifier power supply solutions. Currently, the main application is a two-stage AC / DC + DC / DC topology, as shown in the following example. Figure 1 and Figure 2 As shown, this scheme is costly and cannot meet the requirements for starting the electrolytic cell under load. When the input is the grid voltage, the output voltage is at least the uncontrolled rectified voltage, and the output voltage cannot be slowly soft-started. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to propose a soft-start method and system for hydrogen production power supply. The soft-start method and system for hydrogen production power supply adopts a single-stage hydrogen production AC / DC topology to realize the soft start of the output bus, meet the requirements of electrolyzer load start-up, maintain the power quality characteristics of the AC / DC+DC / DC two-stage topology, and is simple and low in cost.

[0006] To solve the above-mentioned technical problems, the present invention provides a soft-start method for a hydrogen production power supply, comprising a first switch Q1, a line one switch K1, a line two switch K2, a rectifier converter unit and an AC / DC converter unit, and an electrolyzer. Line one includes: the first switch Q1 and the line one switch K1; line two includes: the first switch Q1, the line two switch K2, the rectifier converter unit and the AC / DC converter unit, and the electrolyzer. The method includes the following steps: closing the line two switch K2 and opening the line one switch K1; during the operation of line two... During the process, the rectifier converter unit starts in phase control mode, and its phase control angle gradually increases. The AC / DC converter unit operates in boost mode, and the phase control angle of the rectifier converter unit gradually increases until the output bus voltage of the AC / DC converter unit reaches the preset voltage. During the operation of line two, after the output bus voltage of the AC / DC converter unit reaches the preset voltage, when the zero point of the input voltage of the rectifier converter unit is detected, the switch K1 of line one closes and the switch K2 of line two opens, and the AC / DC converter unit enters a stable operating state.

[0007] Preferably, the rise rate of the output bus voltage of the AC / DC converter unit is controlled by the phase control angle of the rectifier converter unit.

[0008] Preferably, the phase control angle is an angular quantity in the instantaneous value of the AC current of the rectifier converter unit.

[0009] Preferably, the rectifier converter unit is composed of a thyristor full-bridge rectifier topology, and the AC / DC converter unit is composed of a three-phase full-bridge Boost topology.

[0010] To solve the above-mentioned technical problems, the present invention also provides a system employing the above-mentioned soft-start method for hydrogen production power supply, comprising a first switch Q1, a line one switch K1, a line two switch K2, a rectifier converter unit and an AC / DC converter unit, and an electrolyzer. Line one includes: the first switch Q1 and the line one switch K1; line two includes: the first switch Q1, the line two switch K2, the rectifier converter unit and the AC / DC converter unit, and the electrolyzer. The AC / DC converter unit includes an AC / DC converter unit main circuit and an inductor L1 connected to the input terminal of the AC / DC converter unit main circuit. The input terminal of the rectifier converter unit is connected to the first phase voltage output of the power grid. The output terminals of the rectifier converter unit are connected to the input terminals of inductor L1 and the second phase voltage output terminal. The first switch Q1 includes three input terminals and three output terminals, namely: input terminal 1, input terminal 3, input terminal 5, output terminal 2, output terminal 4, and output terminal 6. The output terminal 6 of the first switch Q1 is connected to the input terminal 5 of inductor L1. The output terminal 2 of the first switch Q1 is connected to the input terminal 1 of line 2 switch K2 and the input terminal 1 of line 1 switch K1. The output terminal 4 of the first switch Q1 is connected to the input terminal 3 of line 2 switch K2 and the input terminal 3 of line 1 switch K1. The output terminal 6 of the first switch Q1 is connected to the input terminal 5 of inductor L1.

[0011] Preferably, the rectifier converter unit includes four thyristors, namely: a first thyristor D1, a second thyristor D2, a third thyristor D3, and a fourth thyristor D4;

[0012] The two output terminals of the line switch K2 are connected to the two anode terminals of the first thyristor D1 and the cathode terminal of the second thyristor D2. The four output terminals of the line switch K2 are connected to the two anode terminals of the third thyristor D3 and the cathode terminal of the third thyristor D4. The cathode terminals of the first thyristor D1 and the third thyristor D3 are connected and their outputs are connected to the input terminal of the inductor L1. The two anode terminals of the second thyristor D2 and the fourth thyristor D4 are connected and their outputs are connected to the three input terminals of the inductor L1.

[0013] Preferably, the main circuit of the AC / DC converter unit includes six IGBT devices, and the AC / DC converter unit also includes a bus capacitor C1 connected to the output terminal of the main circuit of the AC / DC converter unit. The six IGBT devices are: a first IGBT device, a second IGBT device, a third IGBT device, a fourth IGBT device, a fifth IGBT device, and a sixth IGBT device.

[0014] The two output terminals of inductor L1 are connected to the two emitter terminals of the first IGBT device and the one collector terminal of the second IGBT device; the four output terminals of inductor L1 are connected to the two emitter terminals of the third IGBT device and the one collector terminal of the fourth IGBT device; the six output terminals of inductor L1 are connected to the two emitter terminals of the fifth IGBT device and the one collector terminal of the sixth IGBT device; the one collector terminal of the first IGBT device, the one collector terminal of the third IGBT device, and the one collector terminal of the fifth IGBT device are connected together, and the output is connected to the anode terminal of the bus capacitor; the two emitter terminals of the second IGBT device, the two emitter terminals of the fourth IGBT device, and the two emitter terminals of the sixth IGBT device are connected together, and the output is connected to the two cathode terminals of the bus capacitor C1.

[0015] Preferably, the rectifier converter unit includes two thyristors and two diodes, namely: a first diode D1, a second thyristor TR2, a third diode D3, and a fourth thyristor TR4; the AC / DC converter unit also includes a bus capacitor C1 connected to the output terminal of the main circuit of the AC / DC converter unit.

[0016] The two output terminals of switch K2 in line 2 are connected to the two anode terminals of the first diode D1 and the cathode terminal of the second thyristor TR2; the four output terminals of switch K2 in line 2 are connected to the two anode terminals of the third diode D3 and the cathode terminal of the fourth thyristor TR4; the cathode terminals of the first diode D1 and the third diode D3 are connected together, and their outputs are connected to the input terminals of inductor L1; the two anode terminals of the second thyristor TR2 and the fourth thyristor TR4 are connected together, and their outputs are connected to the three input terminals of inductor L1.

[0017] Preferably, the rectifier converter unit includes two thyristors and two diodes, namely: a first thyristor TR1, a second diode D2, a third thyristor TR3, and a fourth diode D4; the AC / DC converter unit also includes a bus capacitor C1 connected to the output terminal of the main circuit of the AC / DC converter unit.

[0018] The two output terminals of switch K2 in line 2 are connected to the two anode terminals of the first thyristor TR1 and the cathode terminal of the second diode D2; the four output terminals of switch K2 in line 2 are connected to the two anode terminals of the third thyristor TR3 and the cathode terminal of the fourth diode D4; the cathode terminals of the first thyristor TR1 and the third thyristor TR3 are connected together, and their outputs are connected to the input terminal 1 of inductor L1; the two anode terminals of the second diode D2 and the fourth diode D4 are connected together, and their outputs are connected to the input terminal 3 of inductor L1.

[0019] After adopting the above method and system, a first switch Q1, a line one switch K1, a line two switch K2, a rectifier converter unit and an AC / DC converter unit, and an electrolytic cell are provided. Line two includes: the first switch Q1, the line two switch K2, the rectifier converter unit and the AC / DC converter unit, and the electrolytic cell. Line one includes: the first switch Q1 and the line one switch K1. The method includes the following steps: the line two switch K2 is closed, and the line one switch K1 is open; during the operation of line two, the rectifier converter unit starts in a phase-controlled manner, and its phase control angle gradually increases. The AC / DC converter unit operates in a boost state, and the rectifier converter unit... The phase angle of the AC / DC converter unit gradually increases until the output bus voltage of the AC / DC converter unit reaches the preset voltage. During the operation of line two, after the output bus voltage of the AC / DC converter unit reaches the preset voltage, when the input voltage of the rectifier converter unit is detected to have crossed the zero point, switch K1 of line one closes and switch K2 of line two opens, and the AC / DC converter unit enters a stable operating state. This soft-start method and system for hydrogen production power supply adopts a single-stage hydrogen production AC / DC topology to achieve soft start of the output bus, meeting the requirements for load start of the electrolyzer, maintaining the power quality characteristics of the AC / DC + DC / DC two-stage topology, and is simple and low-cost to implement. Attached Figure Description

[0020] Figure 1 A system for existing AC / DC + DC / DC two-stage hydrogen production topology schemes Figure 1 ;

[0021] Figure 2 A system for existing AC / DC + DC / DC two-stage hydrogen production topology schemes Figure 2 ;

[0022] Figure 3 This is a system connection diagram of the hydrogen production power supply soft-start method and system of the present invention;

[0023] Figure 4 This is a flowchart of the soft-start method for hydrogen production power supply of the present invention;

[0024] Figure 5 This is an overall system diagram of Embodiment 1 or Embodiment 3 of the hydrogen production power supply soft-start method and system of the present invention;

[0025] Figure 6 This is an overall system diagram of Embodiment Six of the hydrogen production power supply soft-start method and system of the present invention;

[0026] Figure 7 This is an overall system diagram of Embodiment Seven of the Hydrogen Production Power Supply Soft Start Method and System of the present invention.

[0027] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer and more understandable, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit the scope of this application.

[0029] In the description of this application, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," and "right," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] Example 1

[0031] Please see Figure 3 , Figure 4 and Figure 5 This embodiment discloses a soft-start method for a hydrogen production power supply, providing a first switch Q1, a line one switch K1, a line two switch K2, a rectifier converter unit, an AC / DC converter unit, and an electrolyzer. Line one includes: the first switch Q1 and the line one switch K1; line two includes: the first switch Q1, the line two switch K2, the rectifier converter unit, the AC / DC converter unit, and the electrolyzer. The method includes the following steps: the line two switch K2 is closed, and the line one switch K1 is open; during the operation of line two, the rectifier converter unit is started in a phase-controlled manner, and its phase control angle gradually increases; the AC / DC converter unit operates in a boost state, and the phase control angle of the rectifier converter unit gradually increases until the output bus voltage of the AC / DC converter unit reaches a preset voltage.

[0032] During the operation of Line 2, after the output bus voltage of the AC / DC converter unit reaches the preset voltage, when the input voltage of the rectifier converter unit is detected to have crossed zero, the switch K1 of Line 1 closes and the switch K2 of Line 2 opens, and the AC / DC converter unit enters a stable operating state.

[0033] Example 2

[0034] This embodiment is based on Embodiment 1. In this embodiment, the rise rate of the output bus voltage of the AC / DC converter unit is controlled by the phase control angle of the rectifier converter unit.

[0035] The phase control angle is the angular quantity in the instantaneous value of the AC current of the rectifier converter unit.

[0036] The rectifier converter unit consists of a thyristor full-bridge rectifier topology, and the AC / DC converter unit consists of a three-phase full-bridge boost converter topology.

[0037] Example 3

[0038] Please see Figure 5 This embodiment discloses a system employing the soft-start method for hydrogen production power supply described in Embodiment 1, including a first switch Q1, a line one switch K1, a line two switch K2, a rectifier converter unit, an AC / DC converter unit, and an electrolyzer. Line two includes: the first switch Q1, the line two switch K2, the rectifier converter unit, the AC / DC converter unit, and the electrolyzer. Line one includes: the first switch Q1 and the line one switch K1. The AC / DC converter unit includes an AC / DC converter unit main circuit and an inductor L1 connected to the input terminal of the AC / DC converter unit main circuit. The input terminal of the rectifier converter unit is connected to the first phase voltage output of the power grid. The first switch Q1 has three input terminals and three output terminals: input terminal 1, input terminal 3, input terminal 5, output terminal 2, output terminal 4, and output terminal 6. The output terminal 6 of the first switch Q1 is connected to the input terminal 5 of the inductor L1. The output terminal 2 of the first switch Q1 is connected to the input terminal 1 of the line 2 switch K2 and the input terminal 1 of the line 1 switch K1. The output terminal 4 of the first switch Q1 is connected to the input terminal 3 of the line 2 switch K2 and the input terminal 3 of the line 1 switch K1. The output terminal 6 of the first switch Q1 is connected to the input terminal 5 of the inductor L1.

[0039] Example 4

[0040] This embodiment is based on Embodiment 3. In this embodiment, the rectifier converter unit includes four thyristors, namely: a first thyristor, a second thyristor, a third thyristor, and a fourth thyristor.

[0041] The two output terminals of the line switch K2 are connected to the two anode terminals of the first thyristor and the one cathode terminal of the second thyristor. The four output terminals of the line switch K2 are connected to the two anode terminals of the third thyristor and the one cathode terminal of the third thyristor. The one cathode terminal of the first thyristor and the one cathode terminal of the third thyristor are connected together, and the output is connected to the one input terminal of the inductor L1. The two anode terminals of the second thyristor and the two anode terminals of the fourth thyristor are connected together, and the output is connected to the three input terminals of the inductor L1.

[0042] Example 5

[0043] This embodiment is based on embodiment three. In this embodiment, the main circuit of the AC / DC converter unit includes six IGBT devices. The AC / DC converter unit also includes a bus capacitor C1 connected to the output terminal of the main circuit of the AC / DC converter unit. The six IGBT devices are: the first IGBT device, the second IGBT device, the third IGBT device, the fourth IGBT device, the fifth IGBT device, and the sixth IGBT device.

[0044] The two output terminals of inductor L1 are connected to the two emitter terminals of the first IGBT device and the one collector terminal of the second IGBT device; the four output terminals of inductor L1 are connected to the two emitter terminals of the third IGBT device and the one collector terminal of the fourth IGBT device; the six output terminals of inductor L1 are connected to the two emitter terminals of the fifth IGBT device and the one collector terminal of the sixth IGBT device; the one collector terminal of the first IGBT device, the one collector terminal of the third IGBT device, and the one collector terminal of the fifth IGBT device are connected together, and the output is connected to the anode terminal of the bus capacitor; the two emitter terminals of the second IGBT device, the two emitter terminals of the fourth IGBT device, and the two emitter terminals of the sixth IGBT device are connected together, and the output is connected to the two cathode terminals of the bus capacitor C1.

[0045] Example 6

[0046] Please see Figure 6 This embodiment is based on Embodiment 3. In this embodiment, the rectifier converter unit includes two thyristors and two diodes, namely: a first diode, a second thyristor, a third diode, and a fourth thyristor; the AC / DC converter unit also includes a bus capacitor C1 connected to the output terminal of the main circuit of the AC / DC converter unit.

[0047] The two output terminals of switch K2 in line 2 are connected to the two anode terminals of the first diode D1 and the cathode terminal of the second thyristor; the four output terminals of switch K2 in line 2 are connected to the two anode terminals of the third diode and the cathode terminal of the fourth thyristor; the cathode terminal of the first diode D1 and the cathode terminal of the third diode D3 are connected together, and the output is connected to the input terminal of inductor L1; the two anode terminals of the second thyristor TR2 and the two anode terminals of the fourth thyristor TR4 are connected together, and the output is connected to the three input terminals of inductor L1.

[0048] Example 7

[0049] Please see Figure 7This embodiment is based on Embodiment 3. In this embodiment, the main circuit of the rectifier converter unit includes two thyristors and two diodes, namely: a first thyristor, a second diode, a third thyristor, and a fourth diode; the AC / DC converter unit also includes a bus capacitor C1 connected to the output terminal of the main circuit of the AC / DC converter unit.

[0050] The two output terminals of switch K2 in line 2 are connected to the two anode terminals of the first thyristor and the one cathode terminal of the second diode; the four output terminals of switch K2 in line 2 are connected to the two anode terminals of the third thyristor and the one cathode terminal of the fourth diode; the one cathode terminal of the first thyristor and the one cathode terminal of the third thyristor are connected together, and the output is connected to the input terminal 1 of inductor L1; the two anode terminals of the second diode and the two anode terminals of the fourth diode are connected together, and the output is connected to the three input terminals of inductor L1.

[0051] The soft-start method and system for hydrogen production power supply adopts a single-stage hydrogen production AC / DC topology to achieve soft start of the output bus, meeting the load start requirements of the electrolyzer, maintaining the power quality characteristics of the AC / DC+DC / DC two-stage topology, and is simple and low-cost to implement.

[0052] The preferred embodiments of this application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and spirit of this application shall be within the scope of the claims.

Claims

1. A soft-start method for a hydrogen production power source, characterized in that, The system provides a first switch Q1, a line one switch K1, a line two switch K2, a rectifier converter unit, an AC / DC converter unit, and an electrolytic cell. Line one includes the first switch Q1 and the line one switch K1, while line two includes the first switch Q1, the line two switch K2, the rectifier converter unit, the AC / DC converter unit, and the electrolytic cell. The method includes the following steps: the line two switch K2 is closed, and the line one switch K1 is opened; during the operation of line two, the rectifier converter unit is started in a phase-controlled manner, and its phase control angle gradually increases; the AC / DC converter unit operates in a boost state, and the phase control angle of the rectifier converter unit gradually increases until the output bus voltage of the AC / DC converter unit reaches a preset voltage. During the operation of Line 2, after the output bus voltage of the AC / DC converter unit reaches the preset voltage, when the input voltage of the rectifier converter unit is detected to have crossed the zero point, the switch K1 of Line 1 closes and the switch K2 of Line 2 opens, and the AC / DC converter unit enters a stable operating state. The system employing the aforementioned soft-start method for hydrogen production power supply includes a first switch Q1, a line one switch K1, a line two switch K2, a rectifier converter unit, an AC / DC converter unit, and an electrolyzer. Line one includes the first switch Q1 and the line one switch K1. Line two includes the first switch Q1, the line two switch K2, the rectifier converter unit, the AC / DC converter unit, and the electrolyzer. The AC / DC converter unit includes an AC / DC converter unit main circuit and an inductor L1 connected to the input terminal of the AC / DC converter unit main circuit. The input terminal of the rectifier converter unit is connected to the first phase voltage output terminal and the second phase voltage output terminal of the power grid. At the output end, the output terminal of the rectifier converter unit is connected to input terminal 1 and input terminal 3 of inductor L1; the first switch Q1 includes three input terminals and three output terminals, namely: input terminal 1, input terminal 3, input terminal 5, output terminal 2, output terminal 4, and output terminal 6; the output terminal 6 of the first switch Q1 is connected to input terminal 5 of inductor L1; the output terminal 2 of the first switch Q1 is connected to input terminal 1 of line 2 switch K2 and input terminal 1 of line 1 switch K1; the output terminal 4 of the first switch Q1 is connected to input terminal 3 of line 2 switch K2 and input terminal 3 of line 1 switch K1; the output terminal 6 of the first switch Q1 is connected to input terminal 5 of inductor L1.

2. The soft-start method for hydrogen production power supply according to claim 1, characterized in that, The rise rate of the output bus voltage of the AC / DC converter unit is controlled by the phase control angle of the rectifier converter unit.

3. The soft-start method for hydrogen production power supply according to claim 2, characterized in that, The phase control angle is the angular quantity in the instantaneous value of the AC current of the rectifier converter unit.

4. The soft-start method for hydrogen production power supply according to claim 1, characterized in that, The rectifier converter unit consists of a thyristor full-bridge rectifier topology, and the AC / DC converter unit consists of a three-phase full-bridge boost converter topology.

5. The method according to claim 1, characterized in that, The rectifier converter unit includes four thyristors: a first thyristor D1, a second thyristor D2, a third thyristor D3, and a fourth thyristor D4. The two output terminals of the line switch K2 are connected to the two anode terminals of the first thyristor D1 and the cathode terminal of the second thyristor D2. The four output terminals of the line switch K2 are connected to the two anode terminals of the third thyristor D3 and the cathode terminal of the third thyristor D4. The cathode terminals of the first thyristor D1 and the third thyristor D3 are connected and their outputs are connected to the input terminal of the inductor L1. The two anode terminals of the second thyristor D2 and the fourth thyristor D4 are connected and their outputs are connected to the three input terminals of the inductor L1.

6. The method according to claim 1, characterized in that, The AC / DC converter unit main circuit includes six IGBT devices, and the AC / DC converter unit also includes a bus capacitor C1 connected to the output terminal of the AC / DC converter unit main circuit. The six IGBT devices are: first IGBT device, second IGBT device, third IGBT device, fourth IGBT device, fifth IGBT device, and sixth IGBT device. The two output terminals of inductor L1 are connected to the two emitter terminals of the first IGBT device and the one collector terminal of the second IGBT device; the four output terminals of inductor L1 are connected to the two emitter terminals of the third IGBT device and the one collector terminal of the fourth IGBT device; the six output terminals of inductor L1 are connected to the two emitter terminals of the fifth IGBT device and the one collector terminal of the sixth IGBT device; the one collector terminal of the first IGBT device, the one collector terminal of the third IGBT device, and the one collector terminal of the fifth IGBT device are connected together, and the output is connected to the anode terminal of the bus capacitor; the two emitter terminals of the second IGBT device, the two emitter terminals of the fourth IGBT device, and the two emitter terminals of the sixth IGBT device are connected together, and the output is connected to the two cathode terminals of the bus capacitor C1.

7. The method according to claim 1, characterized in that, The rectifier converter unit includes two thyristors and two diodes, namely: a first diode D1, a second thyristor TR2, a third diode D3, and a fourth thyristor TR4; the AC / DC converter unit also includes a bus capacitor C1 connected to the output terminal of the main circuit of the AC / DC converter unit. The two output terminals of switch K2 in line 2 are connected to the two anode terminals of the first diode D1 and the cathode terminal of the second thyristor TR2; the four output terminals of switch K2 in line 2 are connected to the two anode terminals of the third diode D3 and the cathode terminal of the fourth thyristor TR4; the cathode terminals of the first diode D1 and the third diode D3 are connected together, and the output is connected to the input terminal of inductor L1. The anode terminals of the second thyristor TR2 and the anode terminals of the fourth thyristor TR4 are connected, and the output is connected to the input terminals of the inductor L1.

8. The method according to claim 1, characterized in that, The rectifier converter unit includes two thyristors and two diodes, namely: a first thyristor TR1, a second diode D2, a third thyristor TR3, and a fourth diode D4; the AC / DC converter unit also includes a bus capacitor C1 connected to the output terminal of the main circuit of the AC / DC converter unit. The two output terminals of switch K2 in line 2 are connected to the two anode terminals of the first thyristor TR1 and the cathode terminal of the second diode D2; the four output terminals of switch K2 in line 2 are connected to the two anode terminals of the third thyristor TR3 and the cathode terminal of the fourth diode D4; the cathode terminals of the first thyristor TR1 and the third thyristor TR3 are connected together, and their outputs are connected to the input terminal 1 of inductor L1; the two anode terminals of the second diode D2 and the fourth diode D4 are connected together, and their outputs are connected to the input terminal 3 of inductor L1.

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