A Tail-Type Topology Circuit and Control Strategy for Driving a Switched Reluctance Motor

Abstract

The present invention relates to the technical field of switched reluctance motor drive control, and specifically to a tail-type topology circuit and control strategy for driving a switched reluctance motor. The present invention solves the problem that existing switched reluctance motor drive control methods destroy the symmetry of the motor windings. A tail-type topology circuit for driving a switched reluctance motor comprises a switched reluctance motor, a capacitor, M power switch bridge arms, and M K-phase inverters; M and K are both positive integers, and K ≥ 2; wherein the switched reluctance motor adopts an N-phase winding structure, and N = M × K; each K-phase winding constitutes an independent symmetrical K-phase winding; each group of symmetrical K-phase windings is star-connected; the two ends of the capacitor are respectively connected to the positive power supply terminal and the negative power supply terminal; the midpoints of the M power switch bridge arms are connected to the neutral points of the M groups of symmetrical K-phase windings in a one-to-one correspondence; and the K-phase output terminals of the M K-phase inverters are connected to the lead terminals of the M groups of symmetrical K-phase windings in a one-to-one correspondence. The present invention is applicable to switched reluctance motors.

Description

Technical Field

[0001] The present invention relates to the technical field of switched reluctance motor drive control, in particular to a tail-type topology circuit and a control strategy for driving a switched reluctance motor. Background Art

[0002] Switched reluctance motor (SRM) is widely used in high speed applications (such as centrifuges, superchargers, and pure electric vehicles) due to its advantages of high rotor structural strength and wide speed regulation range. In current research results, the switched reluctance motor can be driven by a three-phase inverter and controlled by the following method: each set of symmetrical three-phase windings is connected in series, and a voltage source is inserted between two phase windings to ensure that the direction of the current in each phase winding is consistent (such as Figure 1 However, practice has shown that the aforementioned drive control method, due to its inherent limitations, disrupts the symmetry of the motor windings during the drive control process. This results in significant torque ripple and noise in the switched reluctance motor, leading to poor operating performance. Therefore, it is necessary to develop a tail-type topology circuit and control strategy for driving a switched reluctance motor to address the issue of disrupting motor winding symmetry caused by existing switched reluctance motor drive control methods. Summary of the Invention

[0003] In order to solve the problem that the existing switched reluctance motor drive control method destroys the symmetry of the motor winding, the present invention provides a tail topology circuit and a control strategy for driving the switched reluctance motor.

[0004] The present invention is achieved by adopting the following technical solutions:

[0005] A tail-type topology circuit for driving a switched reluctance motor comprises a switched reluctance motor, a capacitor, M power switch bridge arms, and M K-phase inverters; M and K are both positive integers, and K is ≥ 2;

[0006] The switched reluctance motor adopts an N-phase winding structure, where N=M×K; each K-phase winding constitutes an independent set of symmetrical K-phase windings; and each set of symmetrical K-phase windings is star-connected.

[0007] The two ends of the capacitor are connected to the positive power supply terminal and the negative power supply terminal respectively;

[0008] The positive input terminals of the M power switch bridge arms are all connected to the positive power supply terminal; the negative input terminals of the M power switch bridge arms are all connected to the negative power supply terminal; the midpoints of the M power switch bridge arms are connected to the neutral points of the M groups of symmetrical K-phase windings in a one-to-one correspondence;

[0009] The positive input terminals of the M K-phase inverters are all connected to the positive power supply terminal; the negative input terminals of the M K-phase inverters are all connected to the negative power supply terminal; the K-phase output terminals of the M K-phase inverters are connected one-to-one with the lead-out terminals of the M groups of symmetrical K-phase windings.

[0010] A control strategy for driving a switched reluctance motor (the strategy is implemented based on a tail-type topology circuit for driving a switched reluctance motor according to the present invention), the strategy includes the following control modes:

[0011] 1. Motor mode:

[0012] First, a general method is used to control M K-phase inverters so that the DC power supply is converted into M K-phase AC power supplies through the M K-phase inverters, thereby energizing M groups of symmetrical K-phase windings.

[0013] Then, the M power switch bridge arms are controlled so that the actual value of the neutral point current of the M groups of symmetrical K-phase windings is maintained at a preset reference value, thereby making the actual value of the current of each phase winding greater than or equal to 0A, or making the actual value of the current of each phase winding less than or equal to 0A, so that the direction of the current of each phase winding remains consistent, thereby causing the switched reluctance motor to enter motor mode;

[0014] 2. Generator mode:

[0015] First, on the one hand, the M power switch bridge arms are controlled so that a power switch tube in each power switch bridge arm is turned on, and on the other hand, the M K-phase inverters are controlled so that a power switch tube in each K-phase inverter is turned on. At this time, the excitation current starts from the positive power supply end, flows sequentially through a power switch tube turned on in the power switch bridge arm, one phase winding in the symmetrical K-phase winding, and one power switch tube turned on in the K-phase inverter, and then returns to the negative power supply end, or flows sequentially through a power switch tube turned on in the K-phase inverter, one phase winding in the symmetrical K-phase winding, and one power switch tube turned on in the power switch bridge arm, and then returns to the negative power supply end, thereby causing the switched reluctance motor to enter an excitation state.

[0016] After the excitation is completed, the switched reluctance motor continues to rotate, the M power switch bridge arms are turned off, and the switched reluctance motor enters the power generation state.

[0017] The general method includes but is not limited to a trapezoidal current driving method, a sinusoidal current control method, a magnetic field oriented control method, a space vector control method, or a weak magnetic speed control method.

[0018] There are three ways to set the reference value of the neutral point current:

[0019] The first is direct setting;

[0020] The second method is to sum the peak values of the K-phase bridge arm currents of the K-phase inverter and then set the summation result as the reference value of the neutral point current. Taking a three-phase inverter as an example, the setting formula is as follows:

[0021]

[0022] Where: Indicates the reference value of neutral point current; |i leg1 | peak Represents the peak value of the first-phase bridge arm current of the three-phase inverter; |i leg2 | peak Represents the peak value of the second-phase bridge arm current of the three-phase inverter; |i leg3 | peak Indicates the peak value of the third-phase bridge arm current of the three-phase inverter;

[0023] The third method is to sum the absolute values of the amplitude reference values of the K-phase bridge arm current of the K-phase inverter, and then multiply the sum by 1.5 to set it as the reference value of the neutral point current. Taking a three-phase inverter as an example, the setting formula is as follows:

[0024]

[0025] Where: Indicates the reference value of neutral point current; Represents the amplitude reference value of the first-phase bridge arm current of the three-phase inverter; Represents the amplitude reference value of the second-phase bridge arm current of the three-phase inverter; Indicates the amplitude reference value of the third-phase bridge arm current of the three-phase inverter.

[0026] In the generator mode, the power generation performance parameters of the switched reluctance motor can be controlled by controlling M K-phase inverters; the power generation performance parameters include power generation voltage, power generation current, and power generation power.

[0027] Compared with the existing switched reluctance motor drive control method, the present invention fully ensures the symmetry of the motor windings during the drive control process by constructing a new tail topology circuit and control strategy without changing the structure of the switched reluctance motor, thereby effectively reducing the torque pulsation and noise of the switched reluctance motor, thereby effectively improving the operating performance of the switched reluctance motor.

[0028] The present invention effectively solves the problem that the existing switched reluctance motor drive control method destroys the symmetry of the motor winding, and is suitable for the switched reluctance motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the existing switched reluctance motor drive control method.

[0030] Figure 2 This is a schematic diagram of a tail-type topology circuit for driving a switched reluctance motor according to the present invention.

[0031] Figure 3 This is another principle diagram of a tail-type topology circuit for driving a switched reluctance motor according to the present invention.

[0032] Figure 4 This is a schematic diagram of the flow of excitation current in a control strategy for driving a switched reluctance motor described in the present invention.

[0033] Figure 5 This is another schematic diagram of the flow direction of the excitation current in the control strategy for driving the switched reluctance motor described in the present invention.

[0034] In the figure: the dotted arrow indicates the direction of the excitation current. DETAILED DESCRIPTION

[0035] A tail-type topology circuit for driving a switched reluctance motor comprises a switched reluctance motor, a capacitor C, M power switch bridge arms, and M K-phase inverters; M and K are both positive integers, and K is ≥ 2;

[0036] The switched reluctance motor adopts an N-phase winding structure, where N=M×K; each K-phase winding constitutes an independent set of symmetrical K-phase windings; and each set of symmetrical K-phase windings is star-connected.

[0037] The two ends of the capacitor C are connected to the positive power supply terminal and the negative power supply terminal respectively;

[0038] The positive input terminals of the M power switch bridge arms are all connected to the positive power supply terminal; the negative input terminals of the M power switch bridge arms are all connected to the negative power supply terminal; the midpoints of the M power switch bridge arms are connected to the neutral points of the M groups of symmetrical K-phase windings in a one-to-one correspondence;

[0039] The positive input terminals of the M K-phase inverters are all connected to the positive power supply terminal; the negative input terminals of the M K-phase inverters are all connected to the negative power supply terminal; the K-phase output terminals of the M K-phase inverters are connected one-to-one with the lead-out terminals of the M groups of symmetrical K-phase windings.

[0040] A control strategy for driving a switched reluctance motor (the strategy is implemented based on a tail-type topology circuit for driving a switched reluctance motor according to the present invention), the strategy includes the following control modes:

[0041] 1. Motor mode:

[0042] First, a general method is used to control M K-phase inverters so that the DC power supply is converted into M K-phase AC power supplies through the M K-phase inverters, thereby energizing M groups of symmetrical K-phase windings.

[0043] Then, the M power switch bridge arms are controlled so that the actual value of the neutral point current of the M groups of symmetrical K-phase windings is maintained at a preset reference value, thereby making the actual value of the current of each phase winding greater than or equal to 0A, or making the actual value of the current of each phase winding less than or equal to 0A, so that the direction of the current of each phase winding remains consistent, thereby causing the switched reluctance motor to enter motor mode;

[0044] 2. Generator mode:

[0045] First, on the one hand, the M power switch bridge arms are controlled so that a power switch tube in each power switch bridge arm is turned on, and on the other hand, the M K-phase inverters are controlled so that a power switch tube in each K-phase inverter is turned on. At this time, the excitation current starts from the positive power supply end, flows sequentially through a power switch tube turned on in the power switch bridge arm, one phase winding in the symmetrical K-phase winding, and one power switch tube turned on in the K-phase inverter, and then returns to the negative power supply end, or flows sequentially through a power switch tube turned on in the K-phase inverter, one phase winding in the symmetrical K-phase winding, and one power switch tube turned on in the power switch bridge arm, and then returns to the negative power supply end, thereby causing the switched reluctance motor to enter an excitation state.

[0046] After the excitation is completed, the switched reluctance motor continues to rotate, the M power switch bridge arms are turned off, and the switched reluctance motor enters the power generation state.

[0047] The general method includes but is not limited to a trapezoidal current driving method, a sinusoidal current control method, a magnetic field oriented control method, a space vector control method, or a weak magnetic speed control method.

[0048] There are three ways to set the reference value of the neutral point current:

[0049] The first is direct setting;

[0050] The second method is to sum the peak values of the K-phase bridge arm currents of the K-phase inverter and then set the summation result as the reference value of the neutral point current. Taking a three-phase inverter as an example, the setting formula is as follows:

[0051]

[0052] Where: Indicates the reference value of neutral point current; |i leg1 | peak Represents the peak value of the first-phase bridge arm current of the three-phase inverter; |i leg2 | peak Represents the peak value of the second-phase bridge arm current of the three-phase inverter; |i leg3 | peak Indicates the peak value of the third-phase bridge arm current of the three-phase inverter;

[0053] The third method is to sum the absolute values of the amplitude reference values of the K-phase bridge arm current of the K-phase inverter, and then multiply the sum by 1.5 to set it as the reference value of the neutral point current. Taking a three-phase inverter as an example, the setting formula is as follows:

[0054]

[0055] Where: Indicates the reference value of neutral point current; Represents the amplitude reference value of the first-phase bridge arm current of the three-phase inverter; Represents the amplitude reference value of the second-phase bridge arm current of the three-phase inverter; Indicates the amplitude reference value of the third-phase bridge arm current of the three-phase inverter.

[0056] In the generator mode, the power generation performance parameters of the switched reluctance motor can be controlled by controlling M K-phase inverters; the power generation performance parameters include power generation voltage, power generation current, and power generation power.

[0057] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A control strategy for driving a switched reluctance motor, characterized in that: The strategy is based on a tail-type topology circuit for driving a switched reluctance motor. The circuit includes a switched reluctance motor, a capacitor (C), M power switch bridge arms, and M K-phase inverters. M and K are both positive integers, and K ≥ 2. The switched reluctance motor adopts an N-phase winding structure, where N=M×K; each K-phase winding constitutes an independent set of symmetrical K-phase windings; and each set of symmetrical K-phase windings is star-connected. The two ends of the capacitor (C) are connected to the positive power supply terminal and the negative power supply terminal respectively; The positive input terminals of the M power switch bridge arms are all connected to the positive power supply terminal; the negative input terminals of the M power switch bridge arms are all connected to the negative power supply terminal; the midpoints of the M power switch bridge arms are connected to the neutral points of the M groups of symmetrical K-phase windings in a one-to-one correspondence; The positive input terminals of the M K-phase inverters are all connected to the positive power supply terminal; the negative input terminals of the M K-phase inverters are all connected to the negative power supply terminal; the K-phase output terminals of the M K-phase inverters are connected to the lead terminals of the M groups of symmetrical K-phase windings in a one-to-one correspondence; The strategy includes the following control modes:

1. Motor mode: First, a general method is used to control M K-phase inverters so that the DC power supply is converted into M K-phase AC power supplies through the M K-phase inverters, thereby energizing M groups of symmetrical K-phase windings. Then, the M power switch bridge arms are controlled so that the actual value of the neutral point current of the M groups of symmetrical K-phase windings is maintained at a preset reference value, thereby making the actual value of the current of each phase winding greater than or equal to 0A, or making the actual value of the current of each phase winding less than or equal to 0A, so that the direction of the current of each phase winding remains consistent, thereby causing the switched reluctance motor to enter motor mode; 2. Generator mode: First, on the one hand, the M power switch bridge arms are controlled so that a power switch tube in each power switch bridge arm is turned on, and on the other hand, the M K-phase inverters are controlled so that a power switch tube in each K-phase inverter is turned on. At this time, the excitation current starts from the positive power supply end, flows sequentially through a power switch tube turned on in the power switch bridge arm, one phase winding in the symmetrical K-phase winding, and one power switch tube turned on in the K-phase inverter, and then returns to the negative power supply end, or flows sequentially through a power switch tube turned on in the K-phase inverter, one phase winding in the symmetrical K-phase winding, and one power switch tube turned on in the power switch bridge arm, and then returns to the negative power supply end, thereby causing the switched reluctance motor to enter an excitation state. After the excitation is completed, the switched reluctance motor continues to rotate, the M power switch bridge arms are turned off, and the switched reluctance motor enters the power generation state; The general method includes but is not limited to a trapezoidal current drive method, a sinusoidal current control method, a magnetic field oriented control method, a space vector control method, or a weak magnetic speed control method; There are three ways to set the reference value of the neutral point current: The first is direct setting; The second method is to sum the peak values of the K-phase bridge arm currents of the K-phase inverter and then set the summation result as the reference value of the neutral point current. Taking a three-phase inverter as an example, the setting formula is as follows: Where: Indicates the reference value of neutral point current; |i leg1 | peak Represents the peak value of the first-phase bridge arm current of the three-phase inverter; |i leg2 | peak Represents the peak value of the second-phase bridge arm current of the three-phase inverter; |i leg3 | peak Indicates the peak value of the third-phase bridge arm current of the three-phase inverter; The third method is to sum the absolute values of the amplitude reference values of the K-phase bridge arm current of the K-phase inverter, and then multiply the sum by 1.5 to set it as the reference value of the neutral point current. Taking a three-phase inverter as an example, the setting formula is as follows: Where: Indicates the reference value of neutral point current; Represents the amplitude reference value of the first-phase bridge arm current of the three-phase inverter; Represents the amplitude reference value of the second-phase bridge arm current of the three-phase inverter; Indicates the amplitude reference value of the third-phase bridge arm current of the three-phase inverter; In the generator mode, the power generation performance parameters of the switched reluctance motor can be controlled by controlling M K-phase inverters; the power generation performance parameters include power generation voltage, power generation current, and power generation power.

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