An online multi-mode control method for a switched reluctance motor power converter

Abstract

The present invention relates to a multi-mode on-line regulation method for a switched reluctance motor power converter, which can switch and control the switched reluctance motor to operate in a three-phase four-leg drive mode, a three-phase full-bridge drive mode, and a Miller converter drive mode; among them, the three-phase four-leg drive mode and the three-phase full-bridge drive mode can achieve bipolar control of the switched reluctance motor, while the Miller converter can meet the requirements of unipolar control of the switched reluctance motor. Therefore, through this control strategy, multi-mode drive of unipolar drive and bipolar control of the switched reluctance motor can be realized. At the same time, since the three-phase four-leg consists of four independent legs, the topological structure is simple, commercial modular integration can be achieved, the system volume cost can be effectively reduced, the reliability of the power system can be enhanced, and it has important application prospects in electric vehicle drive systems, aerospace, home appliance motor drives, electric tool motors, and mine motor drives.

Description

Technical Field

[0001] The present invention relates to a multi-mode online regulation method for a switched reluctance motor power converter, belonging to the technical field of switched reluctance motor control. Background Art

[0002] The speed regulation system of switched reluctance motors combines the advantages of traditional AC and DC drive systems, with a strong structure, simplicity, low cost, large starting torque, and high efficiency, showing strong market competitiveness in multiple fields such as traction transportation, general industry, aviation industry, and household appliances. The power converter is the core of the switched reluctance motor drive control. The traditional power converter uses an asymmetric half-bridge mode to achieve unipolar control of the current. To improve the utilization rate of the motor winding, the bipolar current control method has also developed to a certain extent. In the traditional variable frequency control of AC motors, the three-phase full-bridge power converter is the main power topology structure, and the inverter with the three-phase full-bridge power converter as the power topology occupies the most important share in the field of motor drive power converters. Therefore, mature power modules have been developed for the single-phase, two-phase, and three-phase power bridge arms of the three-phase full-bridge power converter, which greatly facilitates the modular design of the power motor power converter. However, in traditional inverters, three-phase asymmetric half-bridges, or traditional three-phase four-arm power converters, only single unipolar drive control or bipolar control of the current can be achieved, but it is impossible to achieve multiple-mode power topology switching under a set of power converter topologies and flexibly switch between unipolar drive control and bipolar control of the motor current. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a multi-mode online regulation method for a switched reluctance motor power converter, which can achieve efficient switching of a three-phase switched reluctance motor operating in a three-phase four-arm drive mode, a three-phase full-bridge drive mode, and a Miller converter drive mode.

[0004] The present invention adopts the following technical solutions to solve the above technical problems: The present invention designs a multi-mode online regulation method for a switched reluctance motor power converter to achieve switching of a three-phase switched reluctance motor operating in a three-phase four-arm drive mode, a three-phase full-bridge drive mode, and a Miller converter drive mode. The switched reluctance motor power converter includes a DC power supply V dc , a capacitor C, a first IGBT transistor S1, a second IGBT transistor S2, a third IGBT transistor S3, a fourth IGBT transistor S4, a fifth IGBT transistor S5, a sixth IGBT transistor S6, a seventh IGBT transistor S7, an eighth IGBT transistor S8, and diodes corresponding to each IGBT transistor one by one;

[0005] Among them, the collectors of the IGBT transistors are respectively connected to the cathodes of the corresponding diodes, and the emitters of the IGBT transistors are respectively connected to the anodes of the corresponding diodes; the positive pole of the DC power supply V dc , one end of the capacitor C, the collector of the first IGBT transistor S1, the collector of the third IGBT transistor S3, the collector of the fifth IGBT transistor S5, and the collector of the seventh IGBT transistor S7 are connected to each other. The negative pole of the DC power supply V dc , the other end of the capacitor C, the emitter of the second IGBT transistor S2, the emitter of the fourth IGBT transistor S4, the emitter of the sixth IGBT transistor S6, and the emitter of the eighth IGBT transistor S8 are connected to each other; one end of the A-phase winding in the three-phase switched reluctance motor is respectively connected to the emitter of the first IGBT transistor S1 and the collector of the second IGBT transistor S2; one end of the B-phase winding in the three-phase switched reluctance motor is respectively connected to the emitter of the fifth IGBT transistor S5 and the collector of the sixth IGBT transistor S6; one end of the C-phase winding in the three-phase switched reluctance motor is respectively connected to the emitter of the third IGBT transistor S3 and the collector of the fourth IGBT transistor S4; the other ends of the A-phase winding, B-phase winding, and C-phase winding in the three-phase switched reluctance motor are jointly connected to the emitter of the seventh IGBT transistor S7 and the collector of the eighth IGBT transistor S8;

[0006] The first IGBT transistor S1 and the second IGBT transistor S2, the third IGBT transistor S3 and the fourth IGBT transistor S4, the fifth IGBT transistor S5 and the sixth IGBT transistor S6 form three-phase bridge arms, and the seventh IGBT transistor S7 and the eighth IGBT transistor S8 form a common bridge arm; based on all four groups of bridge arms being in the working state, the power converter is in a three-phase four-bridge-arm drive mode; based on only three-phase bridge arms being in the working state, the power converter is in a three-phase full-bridge drive mode; based on only the upper bridge arms of the three-phase bridge arms and the lower bridge arm of the common bridge arm working together, the power converter is in a Miller converter topology 1 drive mode; based on only the lower bridge arms of the three-phase bridge arms and the upper bridge arm of the common bridge arm working together, the power converter is in a Miller converter topology 2 drive mode.

[0007] As a preferred technical solution of the present invention: based on working in the three-phase four-bridge-arm drive mode, three-phase full-bridge drive mode, Miller converter topology 1 drive mode, and Miller converter topology 2 drive mode corresponding to the three-phase switched reluctance motor, define the mode selection signal g7 corresponding to the seventh IGBT transistor S7, the mode selection signal g8 corresponding to the eighth IGBT transistor S8, and the mode control signal g corresponding to the upper bridge arms of the three-phase bridge arms, namely the first IGBT transistor S1, the third IGBT transistor S3, and the fifth IGBT transistor S5+ , the mode selection signals g corresponding to the second IGBT transistor S2, the fourth IGBT transistor S4, and the sixth IGBT transistor S6 in the lower bridge arms of the three-phase bridge arm - , and perform the following steps:

[0008] Step A. According to the rotor position angle θ of the three-phase switched reluctance motor, combined with the preset turn-on angle θ corresponding to the motor operating mode on and turn-off angle θ off , perform angle position control to obtain the conduction signals g1, g2, g3, g4, g5, g6 corresponding to the A-phase winding, B-phase winding, and C-phase winding of the three-phase switched reluctance motor respectively, and then enter Step B;

[0009] Step B. According to the three-phase winding currents i a 、i b 、i c of the three-phase switched reluctance motor, combined with the current chopping comparison values ±i chop , perform current bipolar chopping control to obtain the current chopping control signals g a 、g b 、g c corresponding to the A-phase winding, B-phase winding, and C-phase winding of the three-phase switched reluctance motor respectively, and then enter Step C;

[0010] Step C. Perform a logical AND operation on the conduction signal g1, the current chopping control signal g a , and the mode selection signal g + to obtain the control signal g1' corresponding to the first IGBT transistor S1; perform a logical AND operation on the conduction signal g2, the current chopping control signal g a , and the mode selection signal g - to obtain the control signal g2' corresponding to the second IGBT transistor S2; perform a logical AND operation on the conduction signal g3, the current chopping control signal g b , and the mode selection signal g + to obtain the control signal g3' corresponding to the third IGBT transistor S3; perform a logical AND operation on the conduction signal g4, the current chopping control signal g b , and the mode selection signal g - to obtain the control signal g4' corresponding to the fourth IGBT transistor S4; perform a logical AND operation on the conduction signal g5, the current chopping control signal g c , and the mode selection signal g + to obtain the control signal g5' corresponding to the fifth IGBT transistor S5; perform a logical AND operation on the conduction signal g6, the current chopping control signal g c , and the mode selection signal g -Perform a logical AND operation to obtain a control signal g6' corresponding to the sixth IGBT transistor S6; perform a logical exclusive OR operation on the conduction signals g1, g3, g5, and perform a logical AND operation on the operation result and the mode selection signal g8 to obtain a control signal g8' corresponding to the eighth IGBT transistor S8; perform a logical exclusive OR operation on the conduction signals g2, g4, g6, and perform a logical AND operation on the operation result and the mode selection signal g7 to obtain a control signal g7' corresponding to the seventh IGBT transistor S7; then enter step D;

[0011] Step D. Apply the control signals g1', g2', g3', g4', g5', g6', g7', g8' corresponding to the first IGBT transistor S1, the second IGBT transistor S2, the third IGBT transistor S3, the fourth IGBT transistor S4, the fifth IGBT transistor S5, the sixth IGBT transistor S6, the seventh IGBT transistor S7, and the eighth IGBT transistor S8 respectively, and control the first IGBT transistor S1, the second IGBT transistor S2, the third IGBT transistor S3, the fourth IGBT transistor S4, the fifth IGBT transistor S5, the sixth IGBT transistor S6, the seventh IGBT transistor S7, and the eighth IGBT transistor S8 respectively.

[0012] As a preferred technical solution of the present invention: The three-phase switched reluctance motor operates in a three-phase four-leg drive mode according to the following steps;

[0013] Step I1. Set the on interval of the switched reluctance motor to 0-18°;

[0014] Step I2. All IGBT transistors in the power converter are operating normally, and the power converter is in the three-phase four-leg drive mode. The bipolar excitation of the three-phase four-leg power converter has a period of every 90° mechanical rotation, which is equivalent to one electrical cycle of the switched reluctance motor. Then, when it is 0 - 3°, the first IGBT transistor S1 and the sixth IGBT transistor S6 are working, and two phases of the three-phase switched reluctance motor BA conduct overlapped; when it is 3 - 15°, the first IGBT transistor S1 and the eighth IGBT transistor S8 are working, and phase A of the three-phase switched reluctance motor conducts alone; when it is 15 - 18°, the first IGBT transistor S1 and the fourth IGBT transistor S4 are working, and two phases of the three-phase switched reluctance motor AC conduct overlapped; when it is 18 - 30°, the seventh IGBT transistor S7 and the fourth IGBT transistor S4 are working, and phase C of the three-phase switched reluctance motor conducts alone; when it is 30 - 33°, the fifth IGBT transistor S5 and the fourth IGBT transistor S4 are working, and two phases of the three-phase switched reluctance motor CB conduct overlapped; when it is 33 - 45°, the eighth IGBT transistor S8 and the fifth IGBT transistor S5 are working, and phase B of the three-phase switched reluctance motor conducts alone; when it is 45 - 48°, the second IGBT transistor S2 and the fifth IGBT transistor S5 are working, and two phases of the three-phase switched reluctance motor BA conduct overlapped; when it is 48 - 60°, the seventh IGBT transistor S7 and the second IGBT transistor S2 are working, and phase A of the three-phase switched reluctance motor conducts alone; when it is 60 - 63°, the third IGBT transistor S3 and the second IGBT transistor S2 are working, and two phases of the three-phase switched reluctance motor AC conduct overlapped; when it is 63 - 75°, the third IGBT transistor S3 and the eighth IGBT transistor S8 are working, and phase C of the three-phase switched reluctance motor conducts alone; when it is 75 - 78°, the third IGBT transistor S3 and the sixth IGBT transistor S6 are working, and two phases of the three-phase switched reluctance motor CB conduct overlapped; when it is 78 - 90°, the seventh IGBT transistor S7 and the sixth IGBT transistor S6 are working, and phase B of the three-phase switched reluctance motor conducts alone.

[0015] As a preferred technical solution of the present invention: The three-phase switched reluctance motor operates in the corresponding three-phase full-bridge drive mode of the power converter according to the following steps;

[0016] Step II1. The turn-on interval of the switched reluctance motor is set to 0 - 30°;

[0017] Step II2. The first IGBT transistor S1 to the sixth IGBT transistor S6 in the power converter operate normally, the seventh IGBT transistor S7 and the eighth IGBT transistor S8 stop operating, and the power converter is in the three-phase full-bridge drive mode. Then, when it is 0-15°, the first IGBT transistor S1 and the sixth IGBT transistor S6 operate, and two phases of the three-phase switched reluctance motor BA conduct overlapped; when it is 15-30°, the first IGBT transistor S1 and the fourth IGBT transistor S4 operate, and two phases of the three-phase switched reluctance motor AC conduct overlapped; when it is 30-45°, the fifth IGBT transistor S5 and the fourth IGBT transistor S4 operate, and two phases of the three-phase switched reluctance motor CB conduct overlapped; when it is 45-60°, the second IGBT transistor S2 and the fifth IGBT transistor S5 operate, and two phases of the three-phase switched reluctance motor BA conduct overlapped; when it is 60-75°, the third IGBT transistor S3 and the second IGBT transistor S2 operate, and two phases of the three-phase switched reluctance motor AC conduct overlapped; when it is 75-90°, the third IGBT transistor S3 and the sixth IGBT transistor S6 operate, and two phases of the three-phase switched reluctance motor CB conduct overlapped.

[0018] As a preferred technical solution of the present invention: The three-phase switched reluctance motor operates in the corresponding Miller converter topology 1 drive mode of the power converter according to the following steps;

[0019] Step III1. The turn-on interval of the switched reluctance motor is set to 0-13°;

[0020] Step III2. The first IGBT transistor S1, the third IGBT transistor S3, the fifth IGBT transistor S5, and the eighth IGBT transistor S8 in the power converter operate normally, the second IGBT transistor S2, the fourth IGBT transistor S4, the sixth IGBT transistor S6, and the seventh IGBT transistor S7 stop operating, and the power converter is in the Miller converter topology 1 drive mode. Then, when it is 0-13°, the first IGBT transistor S1 and the eighth IGBT transistor S8 operate, and the A phase of the three-phase switched reluctance motor conducts alone; when it is 15-28°, the third IGBT transistor S3 and the eighth IGBT transistor S8 operate, and the C phase of the three-phase switched reluctance motor conducts alone; when it is 30-43°, the fifth IGBT transistor S5 and the eighth IGBT transistor S8 operate, and the B phase of the three-phase switched reluctance motor conducts alone.

[0021] As a preferred technical solution of the present invention: The three-phase switched reluctance motor operates in the corresponding Miller converter topology 2 drive mode of the power converter according to the following steps;

[0022] Step IV1. The turn-on interval of the switched reluctance motor is set to 0-13°;

[0023] Step IV2. The first IGBT transistor S1, the third IGBT transistor S3, the fifth IGBT transistor S5, and the eighth IGBT transistor S8 in the power converter stop working, while the second IGBT transistor S2, the fourth IGBT transistor S4, the sixth IGBT transistor S6, and the seventh IGBT transistor S7 work normally. The power converter is in the Miller converter topology 2 drive mode. Among them, from 0 to 13°, the second IGBT transistor S2 and the seventh IGBT transistor S7 work, and phase A of the three-phase switched reluctance motor conducts independently; from 15 to 28°, the fourth IGBT transistor S4 and the seventh IGBT transistor S7 work, and phase C of the three-phase switched reluctance motor conducts independently; from 30 to 43°, the sixth IGBT transistor S6 and the seventh IGBT transistor S7 work, and phase B of the three-phase switched reluctance motor conducts independently.

[0024] For the multi-mode online regulation method of the switched reluctance motor power converter described in the present invention, compared with the prior art by adopting the above technical solutions, the following technical effects are achieved:

[0025] The multi-mode online regulation method of the switched reluctance motor power converter designed in the present invention realizes flexible switching between multiple modes through the logical change of switching devices, and can switch and control the switched reluctance motor to work in the three-phase four-leg drive mode, the three-phase full-bridge drive mode, and the Miller converter drive mode; among them, the three-phase four-leg drive mode and the three-phase full-bridge drive mode can achieve bipolar control of the switched reluctance motor, while the Miller converter can meet the unipolar control requirements of the switched reluctance motor. Therefore, through this control strategy, multi-mode drive of unipolar drive and bipolar control of the switched reluctance motor can be realized. At the same time, since the three-phase four-leg consists of four independent legs and has a simple topological structure, it can be realized for commercial modular integration, which can effectively reduce the system volume cost and enhance the reliability of the power system, and has an important application prospect in electric vehicle drive systems, aerospace, household appliance motor drives, electric tool motors, and mining motor drives. Description of the Drawings

[0026] Figure 1 It is the switched reluctance motor power converter designed in the present invention switched to the three-phase four-leg drive mode;

[0027] Figure 2 It is a schematic diagram of the multi-mode online regulation method of the switched reluctance motor power converter designed in the present invention;

[0028] Figure 3 It is the switched reluctance motor power converter designed in the present invention switched to the three-phase full-bridge drive mode;

[0029] Figure 4It is the design of the present invention that the power converter of the switched reluctance motor switches to the driving mode of Miller converter topology 1;

[0030] Figure 5 It is the design of the present invention that the power converter of the switched reluctance motor switches to the driving mode of Miller converter topology 2. Specific embodiments

[0031] The following further elaborates on the specific embodiments of the present invention in conjunction with the accompanying drawings of the specification.

[0032] The present invention designs a power converter for a switched reluctance motor, which is used to realize the switching of a three-phase switched reluctance motor to operate in a three-phase four-leg driving mode, a three-phase full-bridge driving mode, and a Miller converter driving mode, as Figure 1 shown, and the specific design includes a DC power supply V dc , a capacitor C, a first IGBT transistor S1, a second IGBT transistor S2, a third IGBT transistor S3, a fourth IGBT transistor S4, a fifth IGBT transistor S5, a sixth IGBT transistor S6, a seventh IGBT transistor S7, an eighth IGBT transistor S8, and diodes corresponding to each IGBT transistor one by one.

[0033] Among them, the collectors of each IGBT transistor are respectively connected to the negative electrodes of the corresponding diodes, and the emitters of each IGBT transistor are respectively connected to the positive electrodes of the corresponding diodes; the positive electrode of the DC power supply V dc , one end of the capacitor C, the collector of the first IGBT transistor S1, the collector of the third IGBT transistor S3, the collector of the fifth IGBT transistor S5, and the collector of the seventh IGBT transistor S7 are connected to each other. The negative electrode of the DC power supply V dc , the other end of the capacitor C, the emitter of the second IGBT transistor S2, the emitter of the fourth IGBT transistor S4, the emitter of the sixth IGBT transistor S6, and the emitter of the eighth IGBT transistor S8 are connected to each other; one end of the A-phase winding in the three-phase switched reluctance motor is respectively connected to the emitter of the first IGBT transistor S1 and the collector of the second IGBT transistor S2; one end of the B-phase winding in the three-phase switched reluctance motor is respectively connected to the emitter of the fifth IGBT transistor S5 and the collector of the sixth IGBT transistor S6; one end of the C-phase winding in the three-phase switched reluctance motor is respectively connected to the emitter of the third IGBT transistor S3 and the collector of the fourth IGBT transistor S4; the other ends of the A-phase winding, B-phase winding, and C-phase winding in the three-phase switched reluctance motor are commonly connected to the emitter of the seventh IGBT transistor S7 and the collector of the eighth IGBT transistor S8.

[0034] The first IGBT transistor S1 and the second IGBT transistor S2, the third IGBT transistor S3 and the fourth IGBT transistor S4, the fifth IGBT transistor S5 and the sixth IGBT transistor S6 form three-phase bridge arms, and the seventh IGBT transistor S7 and the eighth IGBT transistor S8 form a common bridge arm; as shown in Table 1.

[0035] Table 1

[0036] Operating mode S7 S8 S1, S3, S5 S2, S4, S6 Three-phase four-leg 1 1 1 1 Three-phase full-bridge 0 0 1 1 Miller converter 1 0 1 1 0 Miller converter 2 1 0 0 1

[0037] Based on all four groups of bridge arms being in the working state, the power converter is in a three-phase four-bridge-arm drive mode; based on only three-phase bridge arms being in the working state, the power converter is in a three-phase full-bridge drive mode; based on only the upper bridge arms of the three-phase bridge arms and the lower bridge arms of the common bridge arm working together, the power converter is in a Miller converter topology 1 drive mode; based on only the lower bridge arms of the three-phase bridge arms and the upper bridge arms of the common bridge arm working together, the power converter is in a Miller converter topology 2 drive mode.

[0038] Furthermore, a multi-mode online regulation method based on the above-mentioned switched reluctance motor power converter is designed. When working in the three-phase four-bridge-arm drive mode, three-phase full-bridge drive mode, Miller converter topology 1 drive mode, and Miller converter topology 2 drive mode corresponding to the three-phase switched reluctance motor, define the mode selection signal g7 corresponding to the seventh IGBT transistor S7, the mode selection signal g8 corresponding to the eighth IGBT transistor S8, the mode control signal g corresponding to the first IGBT transistor S1, the third IGBT transistor S3, and the fifth IGBT transistor S5 of the upper bridge arms of the three-phase bridge arms + and the mode selection signal g corresponding to the second IGBT transistor S2, the fourth IGBT transistor S4, and the sixth IGBT transistor S6 of the lower bridge arms of the three-phase bridge arms - , and perform the following steps as Figure 2 shown.

[0039] Step A. According to the rotor position angle θ of the three-phase switched reluctance motor, combined with the preset turn-on angle θ on and turn-off angle θ off corresponding to the motor working mode, perform angle position control to obtain the conduction signals g1, g2, g3, g4, g5, g6 corresponding to the A-phase winding, B-phase winding, and C-phase winding of the three-phase switched reluctance motor respectively, and then enter Step B.

[0040] Step B. According to the three-phase winding currents i a , i b , i c of the three-phase switched reluctance motor, combined with the current chopping comparison values ±i chop, perform current bipolar chopper control to obtain current chopper control signals g corresponding to the A-phase winding, B-phase winding, and C-phase winding of the three-phase switched reluctance motor respectively a 、g b 、g c , and then enter step C.

[0041] Step C. Perform logical AND operations on the conduction signal g1, current chopper control signal g a 、mode selection signal g + to obtain the control signal g1' corresponding to the first IGBT transistor S1; perform logical AND operations on the conduction signal g2, current chopper control signal g a 、mode selection signal g - to obtain the control signal g2' corresponding to the second IGBT transistor S2; perform logical AND operations on the conduction signal g3, current chopper control signal g b 、mode selection signal g + to obtain the control signal g3' corresponding to the third IGBT transistor S3; perform logical AND operations on the conduction signal g4, current chopper control signal g b 、mode selection signal g - to obtain the control signal g4' corresponding to the fourth IGBT transistor S4; perform logical AND operations on the conduction signal g5, current chopper control signal g c 、mode selection signal g + to obtain the control signal g5' corresponding to the fifth IGBT transistor S5; perform logical AND operations on the conduction signal g6, current chopper control signal g c 、mode selection signal g - to obtain the control signal g6' corresponding to the sixth IGBT transistor S6; perform logical exclusive OR operations on the conduction signals g1, g3, g5, and perform logical AND operations on the operation result and the mode selection signal g8 to obtain the control signal g8' corresponding to the eighth IGBT transistor S8; perform logical exclusive OR operations on the conduction signals g2, g4, g6, and perform logical AND operations on the operation result and the mode selection signal g7 to obtain the control signal g7' corresponding to the seventh IGBT transistor S7; then enter step D.

[0042] Step D. Apply control signals g1', g2', g3', g4', g5', g6', g7', g8' corresponding to the first IGBT transistor S1, the second IGBT transistor S2, the third IGBT transistor S3, the fourth IGBT transistor S4, the fifth IGBT transistor S5, the sixth IGBT transistor S6, the seventh IGBT transistor S7, and the eighth IGBT transistor S8 respectively, and control the first IGBT transistor S1, the second IGBT transistor S2, the third IGBT transistor S3, the fourth IGBT transistor S4, the fifth IGBT transistor S5, the sixth IGBT transistor S6, the seventh IGBT transistor S7, and the eighth IGBT transistor S8 respectively.

[0043] Regarding the operation of the switched reluctance motor when switching between the three-phase four-leg drive mode, the three-phase full-bridge drive mode, and the Miller converter drive mode of the power converter, in practical applications, the specific design is as follows. The switched reluctance motor operates in the three-phase four-leg drive mode corresponding to Figure 1 as shown.

[0044] Step I1. Set the conduction interval of the switched reluctance motor to 0 - 18°.

[0045] Step I2. All IGBT transistors in the power converter are operating normally. The power converter is in a three-phase four-leg drive mode. The bipolar excitation of the three-phase four-leg power converter has a period of every 90° mechanical rotation, which is equivalent to one electrical cycle of the switched reluctance motor. Then, when it is 0 - 3°, the first IGBT transistor S1 and the sixth IGBT transistor S6 are working, and two phases of the three-phase switched reluctance motor BA conduct overlapped; when it is 3 - 15°, the first IGBT transistor S1 and the eighth IGBT transistor S8 are working, and phase A of the three-phase switched reluctance motor conducts alone; when it is 15 - 18°, the first IGBT transistor S1 and the fourth IGBT transistor S4 are working, and two phases of the three-phase switched reluctance motor AC conduct overlapped; when it is 18 - 30°, the seventh IGBT transistor S7 and the fourth IGBT transistor S4 are working, and phase C of the three-phase switched reluctance motor conducts alone; when it is 30 - 33°, the fifth IGBT transistor S5 and the fourth IGBT transistor S4 are working, and two phases of the three-phase switched reluctance motor CB conduct overlapped; when it is 33 - 45°, the eighth IGBT transistor S8 and the fifth IGBT transistor S5 are working, and phase B of the three-phase switched reluctance motor conducts alone; when it is 45 - 48°, the second IGBT transistor S2 and the fifth IGBT transistor S5 are working, and two phases of the three-phase switched reluctance motor BA conduct overlapped; when it is 48 - 60°, the seventh IGBT transistor S7 and the second IGBT transistor S2 are working, and phase A of the three-phase switched reluctance motor conducts alone; when it is 60 - 63°, the third IGBT transistor S3 and the second IGBT transistor S2 are working, and two phases of the three-phase switched reluctance motor AC conduct overlapped; when it is 63 - 75°, the third IGBT transistor S3 and the eighth IGBT transistor S8 are working, and phase C of the three-phase switched reluctance motor conducts alone; when it is 75 - 78°, the third IGBT transistor S3 and the sixth IGBT transistor S6 are working, and two phases of the three-phase switched reluctance motor CB conduct overlapped; when it is 78 - 90°, the seventh IGBT transistor S7 and the sixth IGBT transistor S6 are working, and phase B of the three-phase switched reluctance motor conducts alone.

[0046] In the application, the three-phase switched reluctance motor operates under the three-phase four-leg drive mode corresponding to Figure 1 as shown. When performing bipolar excitation, the conduction interval of the switched reluctance motor needs to be set to 0 - 18°, all legs are operating normally, and the switching devices follow the logic in Table 2.

[0047] Table 2

[0048] Position interval Conducting phase Working switch <![CDATA[i a direction]]> <![CDATA[i c direction]]> <![CDATA[i b direction]]> (0°，3°) BA <![CDATA[S1,S6]]> + - (3°，15°) A <![CDATA[S1,S8]]> + (15°，18°) AC <![CDATA[S1,S4]]> + - (18°，30°) C <![CDATA[S7,S4]]> - (30°，33°) CB <![CDATA[S5,S4]]> - + (33°，45°) B <![CDATA[S8,S5]]> + (45°，48°) BA <![CDATA[S2,S5]]> - + (48°，60°) A <![CDATA[S7,S2]]> - (60°，63°) AC <![CDATA[S3,S2]]> - + (63°，75°) C <![CDATA[S3,S8]]> + (75°，78°) CB <![CDATA[S3,S6]]> + - (78°，90°) B <![CDATA[S7,S6]]> -

[0049] There are three operating modes in the three-phase four-leg drive mode: excitation, freewheeling, and demagnetization. Each operating mode is further divided into single-phase operation and two-phase overlapping operation. Taking phase A winding as an example, there are:

[0050] The A-phase is separately excited. The winding of the A-phase is powered by a DC positive voltage through switch S1 and S8 or switch S2 and S7. When switches S1 and S8 are working, the current in the A-phase winding is in the positive direction; when switches S2 and S7 are working, the current in the A-phase winding is in the negative direction. The voltage equation for this mode can be expressed as:

[0051]

[0052] The A-phase and the C-phase are in series for excitation. The DC positive voltage V dc acts on the series connection of the A-phase and the C-phase through switch S3 and S2 or switch S1 and S4. When switches S2 and S3 are working, the current in the A-phase winding is in the negative direction; when switches S1 and S4 are working, the current in the A-phase winding is in the positive direction. The voltage equation for this mode can be written as:

[0053]

[0054] The A-phase is separately for freewheeling. The winding of the A-phase freewheels through switch S2 and D8 or switch S8 and D2. When switches S2 and D8 are working, the current in the A-phase winding is in the negative direction; when switches S8 and D2 are both working, the current in the A-phase winding is in the positive direction. The voltage equation for this mode can be expressed as:

[0055]

[0056] The windings of the A-phase and the C-phase are in series for freewheeling. The windings of the A-phase and the C-phase freewheel through switch S2 and D4 or switch S4 and D2. When switches S2 and D4 are working, the current in the A-phase winding is in the negative direction and the current in the C-phase winding is in the positive direction; when switches S4 and D2 are both working, the current in the A-phase winding is in the positive direction and the current in the C-phase winding is in the negative direction. The voltage equation for this mode can be expressed as:

[0057]

[0058] The A-phase is separately demagnetized. The winding of the A-phase is demagnetized through switch D8 and D1 or switch D7 and D2. When switches D8 and D1 are working, the current in the A-phase winding is in the negative direction; when switches D7 and D2 are both working, the current in the A-phase winding is in the positive direction. The voltage equation for this mode can be expressed as:

[0059]

[0060] The windings of the A-phase and the C-phase are in series for demagnetization. The windings of the A-phase and the C-phase are demagnetized through switch D4 and D1 or switch D3 and D2. When switches D4 and D1 are working, the current in the A-phase winding is in the negative direction and the current in the C-phase winding is in the positive direction; when switches D3 and D2 are both working, the current in the A-phase winding is in the positive direction and the current in the C-phase winding is in the negative direction. The voltage equation for this mode can be expressed as:

[0061]

[0062] The design is as follows. The three-phase switched reluctance motor operates in the three-phase full-bridge drive mode corresponding to the power converter as Figure 3 shown.

[0063] Step II1. The conduction interval of the switched reluctance motor is set to 0 - 30°.

[0064] Step II2. The first IGBT transistor S1 to the sixth IGBT transistor S6 in the power converter work normally, and the seventh IGBT transistor S7 and the eighth IGBT transistor S8 stop working. The power converter is in the three-phase full-bridge drive mode. Then, from 0 to 15°, the first IGBT transistor S1 and the sixth IGBT transistor S6 work, and the BA phases of the three-phase switched reluctance motor conduct in overlap; from 15 to 30°, the first IGBT transistor S1 and the fourth IGBT transistor S4 work, and the AC phases of the three-phase switched reluctance motor conduct in overlap; from 30 to 45°, the fifth IGBT transistor S5 and the fourth IGBT transistor S4 work, and the CB phases of the three-phase switched reluctance motor conduct in overlap; from 45 to 60°, the second IGBT transistor S2 and the fifth IGBT transistor S5 work, and the BA phases of the three-phase switched reluctance motor conduct in overlap; from 60 to 75°, the third IGBT transistor S3 and the second IGBT transistor S2 work, and the AC phases of the three-phase switched reluctance motor conduct in overlap; from 75 to 90°, the third IGBT transistor S3 and the sixth IGBT transistor S6 work, and the CB phases of the three-phase switched reluctance motor conduct in overlap.

[0065] In application, the three-phase switched reluctance motor operates in the three-phase full-bridge drive mode corresponding to the power converter as Figure 3 shown. This drive mode is transformed by withdrawing the common bridge arm from the three-phase four-leg structure. The withdrawal of the common bridge arm forces two-phase windings to work together to achieve current circulation in this mode. When performing bipolar excitation, the conduction interval of the switched reluctance motor needs to be set to 0 - 30°, and all phase bridge arms work normally. The switching devices follow the logic in Table 3.

[0066] Table 3

[0067] Position interval Conducting phase Working switch <![CDATA[i a direction]]> <![CDATA[i c direction]]> <![CDATA[i b direction]]> (0°，15°) BA <![CDATA[S1,S6]]> + - (15°，30°) AC <![CDATA[S1,S4]]> + - (30°，45°) CB <![CDATA[S5,S4]]> - + (45°，60°) BA <![CDATA[S2,S5]]> - + (60°，75°) AC <![CDATA[S3,S2]]> - + (75°，90°) CB <![CDATA[S3,S6]]> + -

[0068] There are three operating modes in the three-phase full-bridge drive mode: excitation, freewheeling, and demagnetization. Each operating mode requires two-phase overlap operation. Taking phase A as an example, there are:

[0069] Series excitation of phases AC. The windings of phases AC are excited through switches S1, S4 or S3, S2. The current when S1, S4 work is A + C -, when S3 and S2 are working, the current flow direction is A - C + . The voltage equation of this mode can be expressed as:

[0070]

[0071] For the series freewheeling of phases A and C, the windings of phases A and C are freewheeled through switch S1 and diode D3 or switch S3 and diode D1. When S1 and D3 are working, the current is A + C - , when S3 and D1 are working, the current is A - C + . The voltage equation of this mode can be expressed as:

[0072]

[0073] Phase B is in series with phase A for demagnetization. The windings of phases B and A are demagnetized through diodes D6, D1 or diodes D2, D5. When D6 and D1 are working, the current is B + A - , when D5 and D2 are working, the current is B - A + . The voltage equation of this mode can be expressed as:

[0074]

[0075] And according to the following steps, the three-phase switched reluctance motor works under the Miller converter topology 1 drive mode corresponding to the power converter as Figure 4 shown

[0076] Step III1. The conduction interval of the switched reluctance motor is set to 0 - 13°.

[0077] Step III2. The first IGBT transistor S1, the third IGBT transistor S3, the fifth IGBT transistor S5, and the eighth IGBT transistor S8 in the power converter work normally, and the second IGBT transistor S2, the fourth IGBT transistor S4, the sixth IGBT transistor S6, and the seventh IGBT transistor S7 stop working. The power converter is in the Miller converter topology 1 drive mode. Then, from 0 - 13°, the first IGBT transistor S1 and the eighth IGBT transistor S8 work, and phase A of the three-phase switched reluctance motor conducts alone; from 15 - 28°, the third IGBT transistor S3 and the eighth IGBT transistor S8 work, and phase C of the three-phase switched reluctance motor conducts alone; from 30 - 43°, the fifth IGBT transistor S5 and the eighth IGBT transistor S8 work, and phase B of the three-phase switched reluctance motor conducts alone.

[0078] In the application, the three-phase switched reluctance motor operates under the driving mode of the Miller converter topology 1 as shown in Figure 4 . This driving mode is transformed by withdrawing the lower half-switching devices of the phase bridge arm and the upper half-switching devices of the common bridge arm on the basis of the three-phase four-leg. The withdrawal of the four switching devices determines the current flow direction: from the phase winding to the neutral point N. In this mode, it is unipolar excitation. The on-interval of the switched reluctance motor is generally set to 0 - 13°, and the switching devices follow the logic in Table 4.

[0079] Table 4

[0080] Position interval Conducting phase Working switch <![CDATA[i a direction]]> <![CDATA[i c direction]]> <![CDATA[i b direction]]> (0°，13°) A <![CDATA[S1,S8]]> + (15°，28°) C <![CDATA[S3,S8]]> + (30°，43°) B <![CDATA[S5,S8]]> +

[0081] There are three operating modes in the driving mode of the Miller converter topology 1: excitation, freewheeling, and demagnetization. Taking phase A as an example, there are:

[0082] Excitation operating mode. The phase A winding is supplied with a DC positive voltage through the upper transistor S1 and the lower transistor S8 of the common transistor. The current direction is positive. The voltage equation of this mode can be expressed as:

[0083]

[0084] The operating mode of 0-voltage freewheeling is used for chopper control. This operating mode works when the common transistor S8 is turned off and S1 continues to conduct. The current on the phase A winding conducts freewheeling through the switching transistor S1 and the upper diode D7 of the common transistor. The voltage equation of this mode can be expressed as:

[0085]

[0086] -V dc Freewheeling operating mode. It should be noted that the conduction interval of this operating mode depends on the turn-on and turn-off angles. Generally (the turn-on angle is set to 0°, and the turn-off angle is set to 13°), since the conduction interval of each phase is only 15°, the conduction interval of this operating mode is not enough, but this operating mode still exists. This operating mode works when the switching transistors S1 and S8 are both turned off. The current on the phase A winding conducts freewheeling through D2, D7, -V dc for freewheeling. The voltage equation of this mode can be expressed as:

[0087]

[0088] According to the following steps, the three-phase switched reluctance motor operates under the driving mode of the Miller converter topology 2 as shown in Figure 5 .

[0089] Step IV1. The on-interval of the switched reluctance motor is set to 0 - 13°.

[0090] Step IV2. The first IGBT transistor S1, the third IGBT transistor S3, the fifth IGBT transistor S5, and the eighth IGBT transistor S8 in the power converter stop working, while the second IGBT transistor S2, the fourth IGBT transistor S4, the sixth IGBT transistor S6, and the seventh IGBT transistor S7 work normally. The power converter is in the driving mode of Miller converter topology 2. Among them, from 0 to 13°, the second IGBT transistor S2 and the seventh IGBT transistor S7 work, and phase A of the three-phase switched reluctance motor conducts independently; from 15 to 28°, the fourth IGBT transistor S4 and the seventh IGBT transistor S7 work, and phase C of the three-phase switched reluctance motor conducts independently; from 30 to 43°, the sixth IGBT transistor S6 and the seventh IGBT transistor S7 work, and phase B of the three-phase switched reluctance motor conducts independently.

[0091] In application, the three-phase switched reluctance motor works under the driving mode of Miller converter topology 2 corresponding as Figure 5 shown. This driving mode is transformed from the three-phase four-leg driving mode by making the upper half-switching devices on the phase leg and the lower half-switching devices on the common leg stop working. The stop working of the four switching devices determines the current flow direction: from the neutral point N to the phase winding. In this mode, it is unipolar excitation, and the conduction interval of the switched reluctance motor is generally set to 0 - 13°, and the switching devices follow the logic in Table 5.

[0092] Table 5

[0093] Position interval Conducting phase Working switch <![CDATA[i a direction]]> <![CDATA[i c direction]]> <![CDATA[i b direction]]> (0°，13°) A <![CDATA[S2,S7]]> - (15°，28°) C <![CDATA[S4,S7]]> - (30°，43°) B <![CDATA[S6,S7]]> -

[0094] Three working modes in the driving mode of Miller converter topology 2: excitation, freewheeling, and demagnetization. Taking phase A as an example, there are:

[0095] In the excitation working mode, phase A winding is supplied with DC positive voltage through the lower transistor S2 and the upper transistor S7 of the common transistor, and the current direction is negative. The voltage equation of this mode can be expressed as:

[0096]

[0097] The working mode of 0-voltage freewheeling is used for chopper control. This working mode works when the common transistor S7 is turned off and S2 continues to conduct. The current on phase A winding conducts freewheeling through the switching transistor S2 and the lower diode D8 of the common transistor. The voltage equation of this mode can be expressed as:

[0098]

[0099] -V dcThe freewheeling operation mode, which operates when both switch tubes S2 and S7 are turned off. The current in the A-phase winding passes through D1, D8, and -V dc for freewheeling operation. The voltage equation for this mode can be expressed as:

[0100]

[0101] The above-described multi-mode online regulation method for a switched reluctance motor power converter realizes flexible switching between multiple modes through the logical changes of switching devices, and can switch the switched reluctance motor to operate in a three-phase four-leg drive mode, a three-phase full-bridge drive mode, and a Miller converter drive mode; among them, the three-phase four-leg drive mode and the three-phase full-bridge drive mode can achieve bipolar control of the switched reluctance motor, while the Miller converter can meet the requirements of unipolar control of the switched reluctance motor. Therefore, through this control strategy, multi-mode drive of unipolar drive and bipolar control of the switched reluctance motor can be realized. At the same time, since the three-phase four-leg consists of four independent legs, the topological structure is simple, and commercial modular integration can be achieved, which can effectively reduce the system volume cost and enhance the reliability of the power system, and has important application prospects in electric vehicle drive systems, aerospace, home appliance motor drives, electric tool motors, and mine motor drives.

[0102] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art.

Claims

1. A multi-mode on-line regulation method for a switched reluctance motor power converter, which is used to realize the switching of a three-phase switched reluctance motor operating in a three-phase four-leg drive mode, a three-phase full-bridge drive mode, and a Miller converter drive mode, and is characterized in that: The switched reluctance motor power converter includes a DC power supply V dc , a capacitor C, a first IGBT transistor S1, a second IGBT transistor S2, a third IGBT transistor S3, a fourth IGBT transistor S4, a fifth IGBT transistor S5, a sixth IGBT transistor S6, a seventh IGBT transistor S7, an eighth IGBT transistor S8, and diodes corresponding to each IGBT transistor one by one; wherein, the collectors of each IGBT transistor are respectively connected to the negative electrodes of the corresponding diodes, and the emitters of each IGBT transistor are respectively connected to the positive electrodes of the corresponding diodes; the positive electrode of the DC power supply V dc , one end of the capacitor C, the collector of the first IGBT transistor S1, the collector of the third IGBT transistor S3, the collector of the fifth IGBT transistor S5, and the collector of the seventh IGBT transistor S7 are connected to each other; the negative electrode of the DC power supply V dc , the other end of the capacitor C, the emitter of the second IGBT transistor S2, the emitter of the fourth IGBT transistor S4, the emitter of the sixth IGBT transistor S6, and the emitter of the eighth IGBT transistor S8 are connected to each other; one end of the A-phase winding in the three-phase switched reluctance motor is respectively connected to the emitter of the first IGBT transistor S1 and the collector of the second IGBT transistor S2; one end of the B-phase winding in the three-phase switched reluctance motor is respectively connected to the emitter of the fifth IGBT transistor S5 and the collector of the sixth IGBT transistor S6; one end of the C-phase winding in the three-phase switched reluctance motor is respectively connected to the emitter of the third IGBT transistor S3 and the collector of the fourth IGBT transistor S4; the other ends of the A-phase winding, B-phase winding, and C-phase winding in the three-phase switched reluctance motor are commonly connected to the emitter of the seventh IGBT transistor S7 and the collector of the eighth IGBT transistor S8; The first IGBT transistor S1 and the second IGBT transistor S2, the third IGBT transistor S3 and the fourth IGBT transistor S4, the fifth IGBT transistor S5 and the sixth IGBT transistor S6 form three-phase bridge arms, and the seventh IGBT transistor S7 and the eighth IGBT transistor S8 form a common bridge arm; based on all four sets of bridge arms being in the working state, the power converter is in a three-phase four-bridge-arm drive mode; based on only the three-phase bridge arms being in the working state, the power converter is in a three-phase full-bridge drive mode; based on only the upper bridge arms of the three-phase bridge arms and the lower bridge arms of the common bridge arm working together, the power converter is in a Miller converter topology 1 drive mode; based on only the lower bridge arms of the three-phase bridge arms and the upper bridge arms of the common bridge arm working together, the power converter is in a Miller converter topology 2 drive mode.

2. The multi-mode online regulation method for a switched reluctance motor power converter according to claim 1, characterized in that: Based on working under the three-phase four-leg drive mode, three-phase full-bridge drive mode, Miller converter topology 1 drive mode, and Miller converter topology 2 drive mode corresponding to a three-phase switched reluctance motor, define the mode selection signal g7 corresponding to the seventh IGBT transistor S7, the mode selection signal g8 corresponding to the eighth IGBT transistor S8, and the mode control signal g corresponding to the first IGBT transistor S1, the third IGBT transistor S3, and the fifth IGBT transistor S5 in the upper bridge arm of the three-phase bridge arm + , and the mode selection signal g corresponding to the second IGBT transistor S2, the fourth IGBT transistor S4, and the sixth IGBT transistor S6 in the lower bridge arm of the three-phase bridge arm - , and perform the following steps: Step A. According to the rotor position angle θ of the three-phase switched reluctance motor, combining the preset conduction angle θ corresponding to the motor operating mode on and the turn-off angle θ off , perform angle position control to obtain the conduction signals g1, g2, g3, g4, g5, g6 corresponding to the A-phase winding, B-phase winding, and C-phase winding of the three-phase switched reluctance motor respectively, and then enter Step B; Step B. According to the three-phase winding currents i a 、i b 、i c of the three-phase switched reluctance motor, combined with the current chopping comparison values ±i chop , perform bipolar current chopping control to obtain the current chopping control signals g a 、g b 、g c corresponding to the A-phase winding, B-phase winding, and C-phase winding of the three-phase switched reluctance motor respectively, and then enter Step C; Step C. Perform a logical AND operation on the conduction signal g1, the current chopping control signal g a , and the mode selection signal g + to obtain the control signal g1' corresponding to the first IGBT transistor S1; perform a logical AND operation on the conduction signal g2, the current chopping control signal g a , and the mode selection signal g - to obtain the control signal g2' corresponding to the second IGBT transistor S2; perform a logical AND operation on the conduction signal g3, the current chopping control signal g b , and the mode selection signal g + to obtain the control signal g3' corresponding to the third IGBT transistor S3; perform a logical AND operation on the conduction signal g4, the current chopping control signal g b , and the mode selection signal g - to obtain the control signal g4' corresponding to the fourth IGBT transistor S4; perform a logical AND operation on the conduction signal g5, the current chopping control signal g c , and the mode selection signal g + to obtain the control signal g5' corresponding to the fifth IGBT transistor S5; perform a logical AND operation on the conduction signal g6, the current chopping control signal g c , and the mode selection signal g - to obtain the control signal g6' corresponding to the sixth IGBT transistor S6; perform a logical exclusive OR operation on the conduction signals g1, g3, and g5, and perform a logical AND operation on the operation result and the mode selection signal g8 to obtain the control signal g8' corresponding to the eighth IGBT transistor S8; perform a logical exclusive OR operation on the conduction signals g2, g4, and g6, and perform a logical AND operation on the operation result and the mode selection signal g7 to obtain the control signal g7' corresponding to the seventh IGBT transistor S7; then proceed to Step D; Step D. Apply control signals g1', g2', g3', g4', g5', g6', g7', g8' corresponding to the first IGBT transistor S1, the second IGBT transistor S2, the third IGBT transistor S3, the fourth IGBT transistor S4, the fifth IGBT transistor S5, the sixth IGBT transistor S6, the seventh IGBT transistor S7, and the eighth IGBT transistor S8 respectively, and control the first IGBT transistor S1, the second IGBT transistor S2, the third IGBT transistor S3, the fourth IGBT transistor S4, the fifth IGBT transistor S5, the sixth IGBT transistor S6, the seventh IGBT transistor S7, and the eighth IGBT transistor S8 respectively.

3. The multi-mode online regulation method for a switched reluctance motor power converter according to claim 2, wherein: According to the following steps, the three-phase switched reluctance motor operates in the three-phase four-bridge-arm drive mode corresponding to the power converter; Step I1. The conduction interval of the switched reluctance motor is set to 0-18°; Step I2. All IGBT transistors in the power converter are operating normally, and the power converter is in a three-phase four-leg drive mode. The bipolar excitation of the three-phase four-leg power converter has a cycle of every 90° mechanical rotation, which is equivalent to one electrical cycle of the switched reluctance motor. Then, when it is 0 - 3°, the first IGBT transistor S1 and the sixth IGBT transistor S6 are working, and two phases of the three-phase switched reluctance motor BA conduct overlapped; when it is 3 - 15°, the first IGBT transistor S1 and the eighth IGBT transistor S8 are working, and phase A of the three-phase switched reluctance motor conducts alone; when it is 15 - 18°, the first IGBT transistor S1 and the fourth IGBT transistor S4 are working, and two phases of the three-phase switched reluctance motor AC conduct overlapped; when it is 18 - 30°, the seventh IGBT transistor S7 and the fourth IGBT transistor S4 are working, and phase C of the three-phase switched reluctance motor conducts alone; when it is 30 - 33°, the fifth IGBT transistor S5 and the fourth IGBT transistor S4 are working, and two phases of the three-phase switched reluctance motor CB conduct overlapped; when it is 33 - 45°, the eighth IGBT transistor S8 and the fifth IGBT transistor S5 are working, and phase B of the three-phase switched reluctance motor conducts alone; when it is 45 - 48°, the second IGBT transistor S2 and the fifth IGBT transistor S5 are working, and two phases of the three-phase switched reluctance motor BA conduct overlapped; when it is 48 - 60°, the seventh IGBT transistor S7 and the second IGBT transistor S2 are working, and phase A of the three-phase switched reluctance motor conducts alone; when it is 60 - 63°, the third IGBT transistor S3 and the second IGBT transistor S2 are working, and two phases of the three-phase switched reluctance motor AC conduct overlapped; when it is 63 - 75°, the third IGBT transistor S3 and the eighth IGBT transistor S8 are working, and phase C of the three-phase switched reluctance motor conducts alone; when it is 75 - 78°, the third IGBT transistor S3 and the sixth IGBT transistor S6 are working, and two phases of the three-phase switched reluctance motor CB conduct overlapped; when it is 78 - 90°, the seventh IGBT transistor S7 and the sixth IGBT transistor S6 are working, and phase B of the three-phase switched reluctance motor conducts alone.

4. A multi-mode online control method for a switched reluctance motor power converter according to claim 2, characterized in that: According to the following steps, the three-phase switched reluctance motor operates in the corresponding three-phase full-bridge drive mode of the power converter; Step II1. The turn-on interval of the switched reluctance motor is set to 0 - 30°; Step II2. The first IGBT transistor S1 to the sixth IGBT transistor S6 in the power converter operate normally, the seventh IGBT transistor S7 and the eighth IGBT transistor S8 stop operating, and the power converter is in the three-phase full-bridge drive mode. Then, when it is 0 - 15°, the first IGBT transistor S1 and the sixth IGBT transistor S6 operate, and two phases of the three-phase switched reluctance motor BA conduct overlapped; when it is 15 - 30°, the first IGBT transistor S1 and the fourth IGBT transistor S4 operate, and two phases of the three-phase switched reluctance motor AC conduct overlapped; when it is 30 - 45°, the fifth IGBT transistor S5 and the fourth IGBT transistor S4 operate, and two phases of the three-phase switched reluctance motor CB conduct overlapped; when it is 45 - 60°, the second IGBT transistor S2 and the fifth IGBT transistor S5 operate, and two phases of the three-phase switched reluctance motor BA conduct overlapped; when it is 60 - 75°, the third IGBT transistor S3 and the second IGBT transistor S2 operate, and two phases of the three-phase switched reluctance motor AC conduct overlapped; when it is 75 - 90°, the third IGBT transistor S3 and the sixth IGBT transistor S6 operate, and two phases of the three-phase switched reluctance motor CB conduct overlapped.

5. The multi-mode online regulation method of a switched reluctance motor power converter according to claim 2, characterized in that: The three-phase switched reluctance motor operates in the corresponding Miller converter topology 1 drive mode of the power converter according to the following steps; Step III1. The turn-on interval of the switched reluctance motor is set to 0 - 13°; Step III2. The first IGBT transistor S1, the third IGBT transistor S3, the fifth IGBT transistor S5, and the eighth IGBT transistor S8 in the power converter operate normally, the second IGBT transistor S2, the fourth IGBT transistor S4, the sixth IGBT transistor S6, and the seventh IGBT transistor S7 stop operating, and the power converter is in the Miller converter topology 1 drive mode. Then, when it is 0 - 13°, the first IGBT transistor S1 and the eighth IGBT transistor S8 operate, and phase A of the three-phase switched reluctance motor conducts alone; when it is 15 - 28°, the third IGBT transistor S3 and the eighth IGBT transistor S8 operate, and phase C of the three-phase switched reluctance motor conducts alone; when it is 30 - 43°, the fifth IGBT transistor S5 and the eighth IGBT transistor S8 operate, and phase B of the three-phase switched reluctance motor conducts alone.

6. The multi-mode online regulation method for a switched reluctance motor power converter according to claim 2, characterized in that: The three-phase switched reluctance motor operates in the corresponding Miller converter topology 2 drive mode of the power converter according to the following steps; Step IV1. The turn-on interval of the switched reluctance motor is set to 0 - 13°; Step IV2. The first IGBT transistor S1, the third IGBT transistor S3, the fifth IGBT transistor S5, and the eighth IGBT transistor S8 in the power converter stop working, while the second IGBT transistor S2, the fourth IGBT transistor S4, the sixth IGBT transistor S6, and the seventh IGBT transistor S7 work normally. The power converter is in the Miller converter topology 2 driving mode. Among them, from 0 to 13°, the second IGBT transistor S2 and the seventh IGBT transistor S7 work, and the A-phase of the three-phase switched reluctance motor conducts independently; from 15 to 28°, the fourth IGBT transistor S4 and the seventh IGBT transistor S7 work, and the C-phase of the three-phase switched reluctance motor conducts independently; from 30 to 43°, the sixth IGBT transistor S6 and the seventh IGBT transistor S7 work, and the B-phase of the three-phase switched reluctance motor conducts independently.

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