A novel four-quadrant converter and its operating mode switching control method

Abstract

The present invention belongs to the field of rail transit current conversion technology, specifically a new type of four-quadrant converter and its working condition switching control method, which solves the technical problems in the background technology, and includes a DC support module, an AC support module, a controller and a circuit conversion device, the AC support module includes an A bridge arm and a B bridge arm with the same structure, and the A and B bridge arms each include eight IGBTs; the circuit conversion device includes a pulse conversion module and a circuit conversion module; after the controller controls the circuit conversion module to complete the main circuit topology structure transformation of the AC support module, it provides a corresponding control algorithm to make the pulse conversion module output a corresponding drive pulse. The modular design of the present invention can be flexibly transformed according to different working conditions, and has higher redundancy, reliability and flexibility; under the working condition where some switching devices are damaged, the operation of the four-quadrant converter can still be guaranteed, which greatly improves the reliability of the whole vehicle operation and can flexibly improve the harmonic characteristics of the current on the bow-net side.

Description

Technical Field

[0001] The present invention belongs to the technical field of rail transit converter technology, and specifically relates to a novel four-quadrant converter and a working condition switching control method thereof. Background Art

[0002] The four-quadrant converter is a core component of the AC power transmission system in the field of rail transit because of its bidirectional power flow characteristics. Its main function is to complete the AC-DC and DC-AC power conversion. The basic main circuit topology of the current four-quadrant converter usually adopts a fixed single-phase two-level topology, and the topology cannot be changed according to the actual situation or working conditions. On the one hand, when a switching device in the power module is damaged, in order to avoid the expansion of the fault, the four-quadrant converter needs to be shut down, which will inevitably cause partial power loss of the whole vehicle, which has a great impact on the reliability and operating efficiency of the electric locomotive; on the other hand, the topology cannot change with the change of working conditions. In the case of limited cooling capacity, the existing technology cannot achieve better harmonic characteristics without changing the switching frequency. Summary of the invention

[0003] The present invention aims to solve the technical problems that a traditional four-quadrant converter adopts a fixed, single single-phase two-level topology structure. When a switching device in a power module is damaged, the converter needs to be shut down as a whole, which will reduce the operating efficiency; and the topology structure cannot be transformed according to actual conditions or working conditions. A new four-quadrant converter and its working condition switching control method are provided.

[0004] The technical means adopted by the present invention to solve the technical problem are: a novel four-quadrant converter, including a DC support module, an AC support module, a controller and a circuit conversion device;

[0005] The circuit conversion device includes a pulse conversion module and a circuit conversion module. The circuit conversion module includes two input terminals and five output terminals. The first input terminal is connected to a selection contactor K A , select contactor K A Including K A1 End and K A2 The second input terminal is connected to the selection contactor K B , select contactor K B Including K B1 End and K B2 The first output terminal is connected to a circuit breaker K U , the second output terminal passes through the circuit breaker K a1 、Circuit breaker K 5 Connect to K A1 Terminal, circuit breaker K a1 and circuit breaker K 5 The first line is formed between them; the third output terminal passes through the circuit breaker K a2、Circuit breaker K 6 Connect to K A2 Terminal, circuit breaker K a2 and circuit breaker K 6 The second circuit is formed between the fourth output terminal and the circuit breaker K b2 、Circuit breaker K 7 Connect to K B2 Terminal, circuit breaker K b2 and circuit breaker K 7 The third line is formed between them; the fifth output terminal passes through the circuit breaker K b1 、Circuit breaker K 8 Connect to K B1 Terminal, circuit breaker K b1 and circuit breaker K 8 A fourth circuit is formed between the circuit breaker K U The other end is connected in parallel with a circuit breaker K 2 、Circuit breaker K 3 and circuit breaker K 4 , circuit breaker K 2 The other end is connected to the second line, circuit breaker K 3 The other end is connected to the second line, circuit breaker K 4 The other end of is connected to the first line, and a circuit breaker K is connected in parallel between the first line and the second line. a12 , a circuit breaker K is connected in parallel between the second line and the third line a2b2 , a circuit breaker K is connected in parallel between the second line and the fourth line a2b1 , a circuit breaker K is connected in parallel between the first line and the fourth line a1b1 , a circuit breaker K is connected in parallel between the third line and the fourth line b12 ;

[0006] The DC support module consists of two support resistors and three support capacitors, of which the first support capacitor C 1 Connected in parallel to both ends of the positive and negative DC busbars DC, the first supporting resistor R 1 and the second supporting resistor R 2 After being connected in series, they are connected in parallel to both ends of the positive and negative DC busbars DC. The second supporting capacitor C 2 And the third support capacitor C 3 After being connected in series, they are connected in parallel to both ends of the positive and negative DC busbars DC. The first supporting resistor R 1 and the second supporting resistor R 2 The midpoint of the line is connected to the second supporting capacitor C 2 And the third support capacitor C 3 The midpoint of the connection is connected as the output tap U of the DC support module O Leading out a first output terminal connected to the circuit conversion device;

[0007] The AC support module includes an A bridge arm and a B bridge arm with the same structure. The A bridge arm includes eight IGBTs, of which the IGBT A11 、IGBT A12 、IGBT A13 、IGBT A14 Circuit formed in series with IGBT A21 、IGBT A22 、IGBT A23 、IGBT A24 The series circuits are connected in parallel to the positive and negative DC bus ends; IGBT A11 and IGBT A12 The midpoint of the connection line is connected to the IGBT A21 and IGBT A22 The midpoints of the wires are connected, IGBT A13 and IGBT A14 The midpoint of the connection line is connected to the IGBT A23 and IGBT A24 The midpoints of the wires are connected, IGBT A12 and IGBT A13 The midpoint A of the connecting line 1O and IGBT A22 and IGBT A23 The midpoint A of the connecting line 2O The output taps of the A bridge arm are connected to the second output terminal and the third output terminal of the circuit conversion device respectively; the B bridge arm includes eight IGBTs, of which the IGBT B11 、IGBT B12 、IGBT B13 、IGBT B14 Circuit formed in series with IGBT B21 、IGBT B22 、IGBT B23 、IGBT B24 The series circuit is connected in parallel to the positive and negative DC bus ends, and the IGBT B11 and IGBT B12 The midpoint of the connection line is connected to the IGBT B21 and IGBT B22 The midpoints of the wires are connected, IGBT B13 and IGBT B14 The midpoint of the connection line is connected to the IGBT B23 and IGBT B24 The midpoints of the wires are connected, IGBT B12 and IGBT B13 The midpoint of the line is B 1O and IGBT B22 and IGBT B23 The midpoint of the line is B 2OThe fifth output terminal and the fourth output terminal of the circuit conversion device are respectively connected as the B bridge arm output tap;

[0008] The pulse conversion module of the circuit conversion device converts the pulse drive of the eight IGBTs of the A bridge arm and the eight IGBTs of the B bridge arm under the control of the controller. The circuit conversion module completes the conversion of the main circuit topology of the AC support module under the control of the controller; the two input terminals of the circuit conversion device are respectively connected to the AC output terminals A and B of the bow network;

[0009] The controller switches different operating conditions according to the instructions. After the control circuit conversion module completes the main circuit topology structure transformation of the AC support module, it provides the corresponding control algorithm to make the pulse conversion module output the corresponding drive pulse.

[0010] Preferably, it also includes a pre-charging device for charging the DC support module. The pre-charging device is connected to the line between the first input terminal or the second input terminal of the circuit conversion module and the AC output terminal of the bow network. The pre-charging device is composed of a pre-charging resistor and a contactor in parallel. Under the control of the controller, when the four-quadrant converter is started, the pre-charging resistor is connected in series to the main circuit.

[0011] Preferably, a main circuit breaker is also connected to the forward output end of the DC bus.

[0012] Preferably, under the control of the controller, nine working conditions can be switched:

[0013] Working condition 1: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse and has full pulse transmission capability. The controller controls the circuit conversion module to enable the circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K 5 、Circuit breaker K a12 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K b12 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 Port, select contactor K B Connect K B1 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized. 1O and A 2O The midpoint of the B bridge arm outputs a tap B 1O and B 2O is connected to the second input terminal of the circuit conversion device, and the DC support module output tap U OThe main circuit after the transformation forms a four-quadrant converter with a two-level main topology circuit with two tubes in parallel; the controller uses a two-level control algorithm to control all IGBTs to achieve a four-quadrant conversion function;

[0014] Working condition 2: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A11 、IGBT A21 、IGBT A14 、IGBT A24 、IGBT B11 、IGBT B21 、IGBT B14 、IGBT B24 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K 5 、Circuit breaker K a12 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K b12 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 Port, select contactor K B Connect K B1 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized. 1O and A 2O The midpoint of the B bridge arm outputs a tap B 1O and B 2O is connected to the second input terminal of the circuit conversion device, and the DC support module output tap U O The main circuit after the transformation forms a four-quadrant converter of a two-level main topology circuit; the controller uses a two-level control algorithm to control all IGBTs to achieve a four-quadrant conversion function;

[0015] Working condition 3: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A12 、IGBT A22 、IGBT A13 、IGBT A23 、IGBT B12 、IGBT B22 、IGBT B13 、IGBT B23The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K 5 、Circuit breaker K a12 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K b12 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 Port, select contactor K B Connect K B1 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized. 1O and A 2O The midpoint of the B bridge arm outputs a tap B 1O and B 2O is connected to the second input terminal of the circuit conversion device, and the DC support module output tap U O The main circuit after the transformation forms a four-quadrant converter of a two-level main topology circuit; the controller uses a two-level control algorithm to control all IGBTs to achieve a four-quadrant conversion function;

[0016] Working condition 4: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A11 、IGBT A12 、IGBT A13 、IGBT A14 、IGBT B11 、IGBT B12 、IGBT B13 、IGBT B14 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 4 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a1b1 、Circuit breaker K 6 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A2 end, select contactor K B Connect K B2 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized.1O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 2O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the transformed main circuit constitutes a four-quadrant converter of a diode-clamped three-level main topology circuit; the controller uses the NPC control algorithm to control all IGBTs to realize the four-quadrant conversion function;

[0017] Working condition 5: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A22 、IGBT A23 、IGBT A24 、IGBT B21 、IGBT B22 、IGBT B23 、IGBT B24 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 2 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b2 、Circuit breaker K 5 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 End, K B Connect K B1 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 2O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 1O Connected to the B terminal of the circuit conversion device, the transformed main circuit constitutes a four-quadrant converter of a diode-clamped three-level main topology circuit; the controller uses the NPC control algorithm to control all IGBTs to realize the four-quadrant conversion function

[0018] Condition 6: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A22 、IGBT A23、IGBT A24 、IGBT B11 、IGBT B12 、IGBT B13 、IGBT B14 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 3 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b1 、Circuit breaker K 5 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A1 End, K B Connect K B2 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the transformed main circuit constitutes a four-quadrant converter of a diode-clamped three-level main topology circuit; the controller uses the NPC control algorithm to control all IGBTs to realize the four-quadrant conversion function;

[0019] Condition 7: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A11 、IGBT A14 、IGBT B11 、IGBT B14 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 4 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a1b1 、Circuit breaker K 6 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A2 End, K B Connect K B2The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 1O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 2O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the converted loop forms a four-quadrant converter of a three-level main topology circuit with active neutral point clamping; the controller uses the ANPC control algorithm to control all IGBTs to realize the four-quadrant conversion function;

[0020] Working condition 8: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A24 、IGBT B21 、IGBT B24 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 2 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b2 、Circuit breaker K 5 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 End, K B Connect K B1 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 2O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 1O Connected to the B terminal of the circuit conversion device, the converted loop forms a four-quadrant converter of a three-level main topology circuit with active neutral point clamping; the controller uses the ANPC control algorithm to control all IGBTs to realize the four-quadrant conversion function;

[0021] Condition 9: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A24 、IGBT B11 、IGBT B14The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 3 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b1 、Circuit breaker K 5 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A1 End, K B Connect K B2 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the converted loop constitutes a four-quadrant converter of a three-level main topology circuit with active neutral point clamping; the controller uses the ANPC control algorithm to control all BTs to realize the four-quadrant conversion function.

[0022] The present invention also provides a novel operating mode switching control method for a four-quadrant converter, which is implemented based on the novel four-quadrant converter described in the present invention and includes the following steps:

[0023] First, the controller performs a self-test on the pre-charging device, circuit conversion device, DC support module and AC support module. If the test results are all normal, the controller can transform the corresponding topology structure according to the application conditions.

[0024] When the application is selected as a two-level four-quadrant topology, use operating condition 1, operating condition 2 or operating condition 3; when operating at high power and full load, use operating condition 1; when the power is half load or light load, use operating condition 2 or operating condition 3; when the system is operating in operating condition 2, if an IGBT failure occurs A12 、IGBT A13 、IGBT B22 、IGBT B23 When any IGBT breaks down and short-circuits, the operating condition 2 can be converted to the operating condition 3 for normal operation;

[0025] When the application is selected as a three-level four-quadrant topology structure and the IGBT switch device used is a Si device, the main circuit topology structure of the diode clamp composed of working condition four, working condition five or working condition six can be adopted;

[0026] When the application scenario is selected as a three-level four-quadrant topology structure and the IGBT switch device used is a SiC device, an active clamping main circuit topology structure consisting of operating condition seven, operating condition eight or operating condition nine can be adopted.

[0027] The beneficial effects of the present invention are as follows: the main features of the converter are modular design and the main circuit topology can be flexibly changed according to different working conditions, with higher redundancy, reliability and flexibility; under conditions where some switching devices are damaged, the operation of the four-quadrant converter can still be guaranteed, which greatly improves the reliability of the whole vehicle operation, and at the same time, according to different working conditions, the harmonic characteristics of the bow-grid side current can be flexibly improved; on the other hand, the topology structure adopts a modular and unified design, the power device and its two bridge arm modules are exactly the same, and redundant design is carried out for different application environments and application requirements, which reduces the types of power modules, reduces the inventory of spare parts, and reduces product costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is the main circuit topology diagram of the locomotive / EMU electric transmission system; Figure 2 This is a circuit topology diagram of a novel four-quadrant converter described in the present invention.

[0030] Figure 3 This is a schematic diagram of different switchable operating conditions of a controller in a novel four-quadrant converter described in the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be noted that the terms “first” and “second” are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] The present invention provides a certain embodiment: a novel four-quadrant converter, such as Figure 1 and Figure 2 As shown, it includes a DC support module, an AC support module, a controller and a circuit conversion device;

[0035] The circuit conversion device includes a pulse conversion module and a circuit conversion module. The circuit conversion module includes two input terminals and five output terminals. Figure 2 As shown, the first input terminal is connected with a selection contactor K A , select contactor K A Including K A1 End and K A2 The second input terminal is connected to the selection contactor K B , select contactor K B Including K B1 End and K B2 The first output terminal is connected to a circuit breaker K U , the second output terminal passes through the circuit breaker K a1 、Circuit breaker K 5 Connect to K A1 Terminal, circuit breaker K a1 and circuit breaker K 5 The first line is formed between them; the third output terminal passes through the circuit breaker K a2 、Circuit breaker K 6 Connect to K A2 Terminal, circuit breaker K a2 and circuit breaker K 6 The second circuit is formed between the fourth output terminal and the circuit breaker K b2 、Circuit breaker K 7 Connect to K B2 Terminal, circuit breaker K b2 and circuit breaker K 7 The third line is formed between them; the fifth output terminal passes through the circuit breaker K b1 、Circuit breaker K 8 Connect to K B1 Terminal, circuit breaker K b1 and circuit breaker K 8 A fourth circuit is formed between the circuit breaker K U The other end is connected in parallel with a circuit breaker K2 、Circuit breaker K 3 and circuit breaker K 4 , circuit breaker K 2 The other end is connected to the second line, circuit breaker K 3 The other end is connected to the second line, circuit breaker K 4 The other end of is connected to the first line, and a circuit breaker K is connected in parallel between the first line and the second line. a12 , a circuit breaker K is connected in parallel between the second line and the third line a2b2 , a circuit breaker K is connected in parallel between the second line and the fourth line a2b1 , a circuit breaker K is connected in parallel between the first line and the fourth line a1b1 , a circuit breaker K is connected in parallel between the third line and the fourth line b12 ;

[0036] The DC support module consists of two support resistors and three support capacitors, of which the first support capacitor C 1 Connected in parallel to both ends of the positive and negative DC busbars DC, the first supporting resistor R 1 and the second supporting resistor R 2 After being connected in series, they are connected in parallel to both ends of the positive and negative DC busbars DC. The second supporting capacitor C 2 And the third support capacitor C 3 After being connected in series, they are connected in parallel to both ends of the positive and negative DC busbars DC. The first supporting resistor R 1 and the second supporting resistor R 2 The midpoint of the line is connected to the second supporting capacitor C 2 And the third support capacitor C 3 The midpoint of the connection is connected as the output tap U of the DC support module O Leading out a first output terminal connected to the circuit conversion device;

[0037] The AC support module includes an A bridge arm and a B bridge arm with the same structure. The A bridge arm includes eight IGBTs, of which the IGBT A11 、IGBT A12 、IGBT A13 、IGBT A14 Circuit formed in series with IGBT A21 、IGBT A22 、IGBT A23 、IGBT A24 The series circuits are connected in parallel to the positive and negative DC bus ends; IGBT A11 and IGBT A12 The midpoint of the connection line is connected to the IGBT A21 and IGBT A22 The midpoints of the wires are connected, IGBT A13 and IGBT A14 The midpoint of the connection line is connected to the IGBTA23 and IGBT A24 The midpoints of the wires are connected, IGBT A12 and IGBT A13 The midpoint A of the connecting line 1O and IGBT A22 and IGBT A23 The midpoint A of the connecting line 2O The output taps of the A bridge arm are connected to the second output terminal and the third output terminal of the circuit conversion device respectively; the B bridge arm includes eight IGBTs, of which the IGBT B11 、IGBT B12 、IGBT B13 、IGBT B14 Circuit formed in series with IGBT B21 、IGBT B22 、IGBT B23 、IGBT B24 The series circuit is connected in parallel to the positive and negative DC bus ends, and the IGBT B11 and IGBT B12 The midpoint of the connection line is connected to the IGBT B21 and IGBT B22 The midpoints of the wires are connected, IGBT B13 and IGBT B14 The midpoint of the connection line is connected to the IGBT B23 and IGBT B24 The midpoints of the wires are connected, IGBT B12 and IGBT B13 The midpoint of the line is B 1O and IGBT B22 and IGBT B23 The midpoint of the line is B 2O The fifth output terminal and the fourth output terminal of the circuit conversion device are respectively connected as the B bridge arm output tap;

[0038] The pulse conversion module of the circuit conversion device converts the pulse drive of the eight IGBTs of the A bridge arm and the eight IGBTs of the B bridge arm under the control of the controller. The circuit conversion module completes the conversion of the main circuit topology of the AC support module under the control of the controller; the two input terminals of the circuit conversion device are respectively connected to the AC output terminals A and B of the bow network;

[0039] The controller switches different operating conditions according to the instructions. After the control circuit conversion module completes the main circuit topology structure transformation of the AC support module, it provides the corresponding control algorithm to make the pulse conversion module output the corresponding drive pulse.

[0040] Specifically, the first supporting capacitor, the first supporting resistor and the second supporting resistor are connected in series to form a branch, the second supporting capacitor and the third supporting capacitor are connected in series to form a branch, the A bridge arm module and the B bridge arm module are arranged in sequence from left to right and connected in parallel to both ends of the positive and negative DC bus. The control algorithm in the controller is easy for those skilled in the art to think of according to needs, which is an existing conventional technology.

[0041] Furthermore, it also includes a pre-charging device for charging the DC support module. The pre-charging device is connected to the line between the first input terminal or the second input terminal of the circuit conversion module and the AC output terminal of the bow network. The pre-charging device is composed of a pre-charging resistor and a contactor in parallel. Under the control of the controller, when the four-quadrant converter is started, the pre-charging resistor is connected in series to the main circuit.

[0042] Specifically, the pre-charging device mainly realizes the pre-charging function, which is mainly composed of a pre-charging resistor and a contactor in parallel. When the four-quadrant converter is started, the pre-charging resistor is connected in series in the main circuit to charge the DC support module to avoid the impact on the DC support module during direct charging.

[0043] Furthermore, a main circuit breaker is connected to the positive output end of the DC bus, which mainly realizes the output and disconnection of the DC bus and the isolation of the DC power supply and the DC load.

[0044] Further, as a specific implementation of this embodiment, under the control of the controller, nine working conditions can be switched, such as Figure 3 As shown,

[0045] Working condition 1: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse and has full pulse transmission capability. The controller controls the circuit conversion module to enable the circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K 5 、Circuit breaker K a12 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K b12 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 Port, select contactor K B Connect K B1 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized. 1O and A 2O The midpoint of the B bridge arm outputs a tap B 1O and B 2O is connected to the second input terminal of the circuit conversion device, and the DC support module output tap UO The main circuit after the transformation forms a four-quadrant converter with a two-level main topology circuit with two tubes in parallel; the controller uses a two-level control algorithm to control all IGBTs to achieve a four-quadrant conversion function;

[0046] Working condition 2: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A11 、IGBT A21 、IGBT A14 、IGBT A24 、IGBT B11 、IGBT B21 、IGBT B14 、IGBT B24 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K 5 、Circuit breaker K a12 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K b12 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 Port, select contactor K B Connect K B1 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized. 1O and A 2O The midpoint of the B bridge arm outputs a tap B 1O and B 2O is connected to the second input terminal of the circuit conversion device, and the DC support module output tap U O The main circuit after the transformation forms a four-quadrant converter of a two-level main topology circuit; the controller uses a two-level control algorithm to control all IGBTs to achieve a four-quadrant conversion function;

[0047] Working condition 3: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A12 、IGBT A22 、IGBT A13 、IGBT A23 、IGBT B12 、IGBT B22 、IGBT B13 、IGBT B23The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K 5 、Circuit breaker K a12 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K b12 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 Port, select contactor K B Connect K B1 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized. 1O and A 2O The midpoint of the B bridge arm outputs a tap B 1O and B 2O is connected to the second input terminal of the circuit conversion device, and the DC support module output tap U O The main circuit after the transformation forms a four-quadrant converter of a two-level main topology circuit; the controller uses a two-level control algorithm to control all IGBTs to achieve a four-quadrant conversion function;

[0048] Working condition 4: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A11 、IGBT A12 、IGBT A13 、IGBT A14 、IGBT B11 、IGBT B12 、IGBT B13 、IGBT B14 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 4 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a1b1 、Circuit breaker K 6 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A2 end, select contactor K B Connect K B2 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized.1O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 2O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the transformed main circuit constitutes a four-quadrant converter of a diode-clamped three-level main topology circuit; the controller uses the NPC control algorithm to control all IGBTs to realize the four-quadrant conversion function;

[0049] Working condition 5: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A22 、IGBT A23 、IGBT A24 、IGBT B21 、IGBT B22 、IGBT B23 、IGBT B24 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 2 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b2 、Circuit breaker K 5 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 End, K B Connect K B1 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 2O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 1O Connected to the B terminal of the circuit conversion device, the transformed main circuit constitutes a four-quadrant converter of a diode-clamped three-level main topology circuit; the controller uses the NPC control algorithm to control all IGBTs to realize the four-quadrant conversion function

[0050] Condition 6: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A22 、IGBT A23、IGBT A24 、IGBT B11 、IGBT B12 、IGBT B13 、IGBT B14 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 3 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b1 、Circuit breaker K 5 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A1 End, K B Connect K B2 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the transformed main circuit constitutes a four-quadrant converter of a diode-clamped three-level main topology circuit; the controller uses the NPC control algorithm to control all IGBTs to realize the four-quadrant conversion function;

[0051] Condition 7: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A11 、IGBT A14 、IGBT B11 、IGBT B14 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 4 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a1b1 、Circuit breaker K 6 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A2 End, K B Connect K B2The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 1O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 2O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the converted loop forms a four-quadrant converter of a three-level main topology circuit with active neutral point clamping; the controller uses the ANPC control algorithm to control all IGBTs to realize the four-quadrant conversion function;

[0052] Working condition 8: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A24 、IGBT B21 、IGBT B24 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 2 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b2 、Circuit breaker K 5 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 End, K B Connect K B1 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 2O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 1O Connected to the B terminal of the circuit conversion device, the converted loop forms a four-quadrant converter of a three-level main topology circuit with active neutral point clamping; the controller uses the ANPC control algorithm to control all IGBTs to realize the four-quadrant conversion function;

[0053] Condition 9: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A24 、IGBT B11 、IGBT B14The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 3 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b1 、Circuit breaker K 5 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A1 End, K B Connect K B2 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the converted loop constitutes a four-quadrant converter of a three-level main topology circuit with active neutral point clamping; the controller uses the ANPC control algorithm to control all BTs to realize the four-quadrant conversion function.

[0054] The present invention also provides a novel operating mode switching control method for a four-quadrant converter, which is implemented based on the novel four-quadrant converter described in the present invention and includes the following steps:

[0055] First, the controller performs a self-test on the pre-charging device, circuit conversion device, DC support module and AC support module. If the test results are all normal, the controller can transform the corresponding topology structure according to the application conditions.

[0056] When the application is selected as a two-level four-quadrant topology, use operating condition 1, operating condition 2 or operating condition 3; when the power is running at full load, use operating condition 1; when the power is running at half load or light load, the power of light load is less than the power at half load, use operating condition 2 or operating condition 3; when the system is working in operating condition 2, if an IGBT failure occurs A12 、IGBT A13 、IGBT B22 、IGBT B23 When any IGBT breaks down and short-circuits, the operating condition 2 can be converted to the operating condition 3 for normal operation;

[0057] When the application is selected as a three-level four-quadrant topology structure and the IGBT switch device used is a Si device, the main circuit topology structure of the diode clamp composed of working condition four, working condition five or working condition six can be adopted;

[0058] When the application scenario is selected as a three-level four-quadrant topology structure and the IGBT switch device used is a SiC device, an active clamping main circuit topology structure consisting of operating condition seven, operating condition eight or operating condition nine can be adopted.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A new type of four-quadrant converter, It is characterized in that It includes a DC support module, an AC support module, a controller and a circuit conversion device; The circuit conversion device includes a pulse conversion module and a circuit conversion module. The circuit conversion module includes two input terminals and five output terminals. The first input terminal is connected to a selection contactor K A , select contactor K A Including K A1 End and K A2 The second input terminal is connected to the selection contactor K B , select contactor K B Including K B1 End and K B2 The first output terminal is connected to a circuit breaker K U The second output terminal passes through the circuit breaker K a1 、Circuit breaker K 5 Connect to K A1 Terminal, circuit breaker K a1 and circuit breaker K 5 The first line is formed between them; the third output terminal passes through the circuit breaker K a2 、Circuit breaker K 6 Connect to K A2 Terminal, circuit breaker K a2 and circuit breaker K 6 The second circuit is formed between the fourth output terminal and the circuit breaker K b2 、Circuit breaker K 7 Connect to K B2 Terminal, circuit breaker K b2 and circuit breaker K 7 The third line is formed between them; the fifth output terminal passes through the circuit breaker K b1 、Circuit breaker K 8 Connect to K B1 Terminal, circuit breaker K b1 and circuit breaker K 8 A fourth circuit is formed between the circuit breaker K U The other end is connected in parallel with a circuit breaker K 2 、Circuit breaker K 3 and circuit breaker K 4 , circuit breaker K 2 The other end is connected to the second line, circuit breaker K 3 The other end is connected to the second line, circuit breaker K 4 The other end of is connected to the first line, and a circuit breaker K is connected in parallel between the first line and the second line. a12 , a circuit breaker K is connected in parallel between the second line and the third line a2b2 , a circuit breaker K is connected in parallel between the second line and the fourth line a2b1 , a circuit breaker K is connected in parallel between the first line and the fourth line a1b1 , a circuit breaker K is connected in parallel between the third line and the fourth line b12 ; The DC support module consists of two support resistors and three support capacitors, of which the first support capacitor C 1 Connected in parallel to both ends of the positive and negative DC busbars DC, the first supporting resistor R 1 and the second supporting resistor R 2 After being connected in series, they are connected in parallel to both ends of the positive and negative DC busbars DC. The second supporting capacitor C 2 And the third support capacitor C 3 After being connected in series, they are connected in parallel to both ends of the positive and negative DC busbars DC. The first supporting resistor R 1 and the second supporting resistor R 2 The midpoint of the line is connected to the second supporting capacitor C 2 And the third support capacitor C 3 The midpoint of the connection is connected as the output tap U of the DC support module O Leading out a first output terminal connected to the circuit conversion module; The AC support module includes an A bridge arm and a B bridge arm with the same structure. The A bridge arm includes eight IGBTs, of which the IGBT A11 、IGBT A12 、IGBT A13 、IGBT A14 Circuit formed in series with IGBT A21 、IGBT A22 、IGBT A23 、IGBT A24 The series circuits are connected in parallel to the positive and negative DC bus ends; IGBT A11 and IGBT A12 The midpoint of the connection line is connected to the IGBT A21 and IGBT A22 The midpoints of the wires are connected, IGBT A13 and IGBT A14 The midpoint of the connection line is connected to the IGBT A23 and IGBT A24 The midpoints of the wires are connected, IGBT A12 and IGBT A13 The midpoint A of the connecting line 1O and IGBT A22 and IGBT A23 The midpoint A of the connecting line 2O The A bridge arm is connected to the second output terminal and the third output terminal of the circuit conversion module as the output tap of the A bridge arm; the B bridge arm includes eight IGBTs, of which the IGBT B11 、IGBT B12 、IGBT B13 、IGBT B14 Circuit formed in series with IGBT B21 、IGBT B22 、IGBT B23 、IGBT B24 The series circuit is connected in parallel to the positive and negative DC bus ends, and the IGBT B11 and IGBT B12 The midpoint of the connection line is connected to the IGBT B21 and IGBT B22 The midpoints of the wires are connected, IGBT B13 and IGBT B14 The midpoint of the connection line is connected to the IGBT B23 and IGBT B24 The midpoints of the wires are connected, IGBT B12 and IGBT B13 The midpoint of the line is B 1O and IGBT B22 and IGBT B23 The midpoint of the line is B 2O The fifth output terminal and the fourth output terminal of the circuit conversion module are respectively connected as the B bridge arm output tap; The pulse conversion module of the circuit conversion device converts the pulse drive of the eight IGBTs of the A bridge arm and the eight IGBTs of the B bridge arm under the control of the controller. The circuit conversion module completes the conversion of the main circuit topology of the AC support module under the control of the controller; the two input ends of the circuit conversion module are respectively connected to the AC output ends A and B of the bow network; The controller switches different operating conditions according to the instructions. After the control circuit conversion module completes the main circuit topology structure transformation of the AC support module, it provides the corresponding control algorithm to make the pulse conversion module output the corresponding drive pulse.

2. A novel four-quadrant converter according to claim 1, It is characterized in that It also includes a pre-charging device for charging the DC support module. The pre-charging device is connected to the line between the first input terminal or the second input terminal of the circuit conversion module and the AC output terminal of the bow network. The pre-charging device is composed of a pre-charging resistor and a contactor in parallel. Under the control of the controller, when the four-quadrant converter is started, the pre-charging resistor is connected in series to the main circuit.

3. A novel four-quadrant converter according to claim 1, It is characterized in that A main circuit breaker is also connected to the positive output end of the DC bus.

4. A novel four-quadrant converter according to any one of claims 1 to 3, It is characterized in that Under the control of the controller, nine working conditions can be switched: Working condition 1: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse and has full pulse transmission capability. The controller controls the circuit conversion module to enable the circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K 5 、Circuit breaker K a12 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K b12 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 Port, select contactor K B Connect K B1 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized. 1O and A 2O The middle point of the B bridge arm outputs a tap B. 1O and B 2O is connected and connected to the second input terminal of the circuit conversion module, and the DC support module output tap U O The main circuit after the transformation forms a four-quadrant converter with a two-level main topology circuit with two tubes in parallel; the controller uses a two-level control algorithm to control all IGBTs to achieve a four-quadrant conversion function; Working condition 2: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A11 、IGBT A21 、IGBT A14 、IGBT A24 、IGBT B11 、IGBT B21 、IGBT B14 、IGBT B24 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K 5 、Circuit breaker K a12 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K b12 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 Port, select contactor K B Connect K B1 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized. 1O and A 2O The midpoint of the B bridge arm outputs a tap B 1O and B 2O is connected to the second input terminal of the circuit conversion device, and the DC support module output tap U O The main circuit after the transformation forms a four-quadrant converter of a two-level main topology circuit; the controller uses a two-level control algorithm to control all IGBTs to achieve a four-quadrant conversion function; Working condition 3: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A12 、IGBT A22 、IGBT A13 、IGBT A23 、IGBT B12 、IGBT B22 、IGBT B13 、IGBT B23 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K 5 、Circuit breaker K a12 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K b12 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 Port, select contactor K B Connect K B1 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized. 1O and A 2O The midpoint of the B bridge arm outputs a tap B 1O and B 2O is connected to the second input terminal of the circuit conversion device, and the DC support module output tap U O The main circuit after the transformation forms a four-quadrant converter of a two-level main topology circuit; the controller uses a two-level control algorithm to control all IGBTs to achieve a four-quadrant conversion function; Working condition 4: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A11 、IGBT A12 、IGBT A13 、IGBT A14 、IGBT B11 、IGBT B12 、IGBT B13 、IGBT B14 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 4 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a1b1 、Circuit breaker K 6 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A2 end, select contactor K B Connect K B2 The remaining circuit breakers are all in the disconnected state, and the midpoint output tap A of the A bridge arm can be realized. 1O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 2O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the transformed main circuit constitutes a four-quadrant converter of a diode-clamped three-level main topology circuit; the controller uses the NPC control algorithm to control all IGBTs to realize the four-quadrant conversion function; Working condition 5: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A22 、IGBT A23 、IGBT A24 、IGBT B21 、IGBT B22 、IGBT B23 、IGBT B24 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 2 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b2 、Circuit breaker K 5 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 End, K B Connect K B1 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 2O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 1O Connected to the B terminal of the circuit conversion device, the transformed main circuit constitutes a four-quadrant converter of a diode-clamped three-level main topology circuit; the controller uses the NPC control algorithm to control all IGBTs to realize the four-quadrant conversion function Condition 6: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A22 、IGBT A23 、IGBT A24 、IGBT B11 、IGBT B12 、IGBT B13 、IGBT B14 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 3 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b1 、Circuit breaker K 5 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A1 End, K B Connect K B2 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the transformed main circuit constitutes a four-quadrant converter of a diode-clamped three-level main topology circuit; the controller uses the NPC control algorithm to control all IGBTs to realize the four-quadrant conversion function; Condition 7: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A11 、IGBT A14 、IGBT B11 、IGBT B14 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 4 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a1b1 、Circuit breaker K 6 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A2 End, K B Connect K B2 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 1O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 2O Connect to the A terminal of the circuit converter, B 2O Connected to the B terminal of the circuit conversion device, the converted loop forms a four-quadrant converter of a three-level main topology circuit with active neutral point clamping; the controller uses the ANPC control algorithm to control all IGBTs to realize the four-quadrant conversion function; Working condition 8: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A24 、IGBT B21 、IGBT B24 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 2 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b2 、Circuit breaker K 5 、Circuit breaker K 8 Close, contactor K will be selected A Connect K A1 End, K B Connect K B1 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 2O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 1O Connected to the B terminal of the circuit conversion device, the converted loop forms a four-quadrant converter of a three-level main topology circuit with active neutral point clamping; the controller uses the ANPC control algorithm to control all IGBTs to realize the four-quadrant conversion function; Condition 9: The controller enables pulse conversion and circuit conversion. The pulse conversion module enables the IGBT pulse. A21 、IGBT A24 、IGBT B11 、IGBT B14 The remaining IGBTs have the ability to transmit high and low levels. The controller controls the circuit conversion module to make the circuit breaker K U 、Circuit breaker K 3 、Circuit breaker K a1 、Circuit breaker K a2 、Circuit breaker K b1 、Circuit breaker K b2 、Circuit breaker K a2b1 、Circuit breaker K 5 、Circuit breaker K 7 Close, contactor K will be selected A Connect K A1 End, K B Connect K B2 The remaining circuit breakers are all disconnected, and the midpoint of the A bridge arm is output to tap A. 2O and U O Connect the midpoint of the B bridge arm to the output tap B 1O and U O Connected, A 1O Connect to the A terminal of the circuit converter, B 2O It is connected to the B terminal of the circuit conversion device, and the converted loop constitutes a four-quadrant converter of a three-level main topology circuit with active neutral point clamping; the controller uses an ANPC control algorithm to control all IGBTs to realize the four-quadrant conversion function.

5. A novel operating mode switching control method for four-quadrant converter, It is characterized in that The method is implemented based on a novel four-quadrant converter according to claim 4, and comprises the following steps: First, the controller performs a self-test on the pre-charging device, circuit conversion device, DC support module and AC support module. If the test results are all normal, the controller can transform the corresponding topology structure according to the application conditions. When the application is selected as a two-level four-quadrant topology, use operating condition 1, operating condition 2 or operating condition 3; when operating at high power and full load, use operating condition 1; when the power is half load or light load, use operating condition 2 or operating condition 3; when the system is operating in operating condition 2, if an IGBT failure occurs A12 、IGBT A13 、IGBT B22 、IGBT B23 When any IGBT breaks down and short-circuits, the operating condition 2 can be converted to the operating condition 3 for normal operation; When the application is selected as a three-level four-quadrant topology structure and the IGBT switch device used is a Si device, the main circuit topology structure of the diode clamp composed of working condition four, working condition five or working condition six can be adopted; When the application scenario is selected as a three-level four-quadrant topology structure and the IGBT switch device used is a SiC device, an active clamping main circuit topology structure consisting of operating condition seven, operating condition eight or operating condition nine can be adopted.

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