Tail-type topology circuit for driving switched reluctance motor and control strategy

Abstract

The invention relates to the technical field of switch reluctance motor driving control, in particular to a tail-type topology circuit for driving a switch reluctance motor and a control strategy. The problem that the symmetry of motor windings is damaged by an existing switched reluctance motor driving control method is solved. The invention discloses a tail-type topology circuit for driving a switched reluctance motor. The tail-type topology circuit comprises the switched reluctance motor, a capacitor, M power switch bridge arms and M K-phase inverters, m and K are positive integers, and K is greater than or equal to 2; wherein the switched reluctance motor adopts an N-phase winding structure, and N is equal to M * K; each K-phase winding forms a group of independent symmetrical K-phase windings; each group of symmetrical K-phase windings is in star connection; two ends of the capacitor are respectively connected with the positive power supply end and the negative power supply end; the middle points of the M power switch bridge arms are connected with the neutral points of the M groups of symmetrical K-phase windings in a one-to-one correspondence manner; and the K-phase output ends of the M K-phase inverters are connected with the leading-out ends of the M groups of symmetrical K-phase windings in a one-to-one correspondence manner. The invention is suitable for the switched reluctance motor.

Description

Technical Field

[0001] The 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, pure electric vehicles, etc.) because of its advantages of high rotor structure strength and wide speed regulation range. In the 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 the two-phase windings to ensure that the direction of the current in each phase winding is consistent (such as Figure 1 As shown). However, practice shows that the above drive control method will destroy the symmetry of the motor windings during the drive control process due to its own principle limitations, which will cause the switched reluctance motor to generate large torque pulsation and noise, resulting in poor operating performance of the switched reluctance motor. Based on this, it is necessary to invent a tail topology circuit and control strategy for driving a switched reluctance motor to solve the problem that the existing switched reluctance motor drive control method destroys the symmetry of the motor windings. 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≥2;

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

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

[0008] The positive input ends of the M power switch bridge arms are all connected to the positive power supply end; the negative input ends of the M power switch bridge arms are all connected to the negative power supply end; the midpoints of the M power switch bridge arms are connected to the neutral points of the M groups of symmetrical K-phase windings one by one;

[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] Firstly, a general method is adopted to control M K-phase inverters so that a DC power source is converted into M K-phase AC power sources 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 is consistent, thereby making the switched reluctance motor enter the 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 is turned on in each power switch bridge arm, and on the other hand, the M K-phase inverters are controlled so that a power switch tube is turned on in each K-phase inverter; at this time, the excitation current starts from the positive power supply end, flows through a power switch tube turned on in the power switch bridge arm, one phase winding in the symmetrical K-phase winding, and a power switch tube turned on in the K-phase inverter in sequence, and then returns to the negative power supply end, or flows through a power switch tube turned on in the K-phase inverter, one phase winding in the symmetrical K-phase winding, and a power switch tube turned on in the power switch bridge arm in sequence, and then returns to the negative power supply end, thereby making the switched reluctance motor enter the 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 sum 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 result 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; It represents 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, without changing the structure of the switched reluctance motor, fully ensures the symmetry of the motor windings during the drive control process by constructing a new tail topology circuit and control strategy, 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 It is a schematic diagram of a tail-type topology circuit for driving a switched reluctance motor according to the present invention.

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

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

[0033] Figure 5 It 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≥2;

[0036] The switched reluctance motor adopts an N-phase winding structure, and N=M×K; each K-phase winding constitutes a group of independent symmetrical K-phase windings; each group 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 ends of the M power switch bridge arms are all connected to the positive power supply end; the negative input ends of the M power switch bridge arms are all connected to the negative power supply end; the midpoints of the M power switch bridge arms are connected to the neutral points of the M groups of symmetrical K-phase windings one by one;

[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] Firstly, a general method is adopted to control M K-phase inverters so that a DC power source is converted into M K-phase AC power sources 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 is consistent, thereby making the switched reluctance motor enter the 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 is turned on in each power switch bridge arm, and on the other hand, the M K-phase inverters are controlled so that a power switch tube is turned on in each K-phase inverter; at this time, the excitation current starts from the positive power supply end, flows through a power switch tube turned on in the power switch bridge arm, one phase winding in the symmetrical K-phase winding, and a power switch tube turned on in the K-phase inverter in sequence, and then returns to the negative power supply end, or flows through a power switch tube turned on in the K-phase inverter, one phase winding in the symmetrical K-phase winding, and a power switch tube turned on in the power switch bridge arm in sequence, and then returns to the negative power supply end, thereby making the switched reluctance motor enter the 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 sum 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 result 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; It represents 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 the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these are only examples, and the protection 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, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A tail-type topology circuit for driving a switched reluctance motor, characterized in that: It 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, and N=M×K; each K-phase winding constitutes a group of independent symmetrical K-phase windings; each group 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 ends of the M power switch bridge arms are all connected to the positive power supply end; the negative input ends of the M power switch bridge arms are all connected to the negative power supply end; the midpoints of the M power switch bridge arms are connected to the neutral points of the M groups of symmetrical K-phase windings one by one; 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.

2. A control strategy for driving a switched reluctance motor, the strategy being implemented based on a tail-type topology circuit for driving a switched reluctance motor as claimed in claim 1, characterized in that: The strategy includes the following control modes:

1. Motor mode: Firstly, a general method is adopted to control M K-phase inverters so that a DC power source is converted into M K-phase AC power sources 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 is consistent, thereby making the switched reluctance motor enter the motor mode; 2. Generator mode: First, on the one hand, the M power switch bridge arms are controlled so that a power switch tube is turned on in each power switch bridge arm, and on the other hand, the M K-phase inverters are controlled so that a power switch tube is turned on in each K-phase inverter; at this time, the excitation current starts from the positive power supply end, flows through a power switch tube turned on in the power switch bridge arm, one phase winding in the symmetrical K-phase winding, and a power switch tube turned on in the K-phase inverter in sequence, and then returns to the negative power supply end, or flows through a power switch tube turned on in the K-phase inverter, one phase winding in the symmetrical K-phase winding, and a power switch tube turned on in the power switch bridge arm in sequence, and then returns to the negative power supply end, thereby making the switched reluctance motor enter the 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.

3. A control strategy for driving a switched reluctance motor according to claim 2, characterized in that: 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.

4. A control strategy for driving a switched reluctance motor according to claim 2, characterized in that: 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 sum 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 result 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; It represents the amplitude reference value of the third-phase bridge arm current of the three-phase inverter.

5. A control strategy for driving a switched reluctance motor according to claim 2, characterized in that: 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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