US-20260128704-A1 - TOPOLOGICAL CIRCUIT AND CONTROL STRATEGY FOR DRIVING SWITCHED RELUCTANCE MOTOR (SRM)

US20260128704A1US 20260128704 A1US20260128704 A1US 20260128704A1US-20260128704-A1

Abstract

Provided are a topological circuit and a control strategy for driving a switched reluctance motor (SRM). In one aspect, an SRM has an N-phase winding structure, N=M×K; the symmetrical K-phase windings in each set of symmetrical K-phase windings are connected in a star configuration; midpoints of M power switch bridge arms are connected to neutral points of M sets of symmetrical K-phase windings in one-to-one correspondence; and K output terminals of M K-phase inverters are connected to lead-out terminals of the M sets of symmetrical K-phase windings in one-to-one correspondence. In another aspect, an SRM has N phases of windings connected in a star configuration; a midpoint of an additional bridge arm is connected to a neutral point for the N phases of windings; midpoints of N inverter bridge arms are connected to lead-out terminals of the N phases of windings in one-to-one correspondence.

Inventors

Haitao Sun

Assignees

TAIYUAN UNIVERSITY OF TECHNOLOGY

Dates

Publication Date: 20260507
Application Date: 20251030
Priority Date: 20241101

Claims (11)

1 . A topological circuit for driving a switched reluctance motor (SRM), comprising: an SRM, a capacitor (C), M power switch bridge arms, and M K-phase inverters, M and K each being a positive integer, and K≥2, wherein the SRM has an N-phase winding structure, N=M×K; every K phases of windings form an independent set of symmetrical K-phase windings; and the symmetrical K-phase windings in each set of symmetrical K-phase windings are connected in a star configuration; two terminals of the capacitor (C) are respectively connected to a positive power terminal and a negative power terminal; positive input terminals of the M power switch bridge arms are connected to the positive power terminal; negative input terminals of the M power switch bridge arms are connected to the negative power terminal; and midpoints of the M power switch bridge arms are connected to neutral points of M sets of symmetrical K-phase windings in one-to-one correspondence; and positive input terminals of the M K-phase inverters are connected to the positive power terminal; negative input terminals of the M K-phase inverters are connected to the negative power terminal; and K output terminals of the M K-phase inverters are connected to lead-out terminals of the M sets of symmetrical K-phase windings in one-to-one correspondence.
2 . A control strategy for driving a switched reluctance motor (SRM), wherein the control strategy for driving an SRM is realized based on the topological circuit for driving an SRM according to claim 1 , and the control strategy for driving an SRM comprises following control modes: I: a motor mode: controlling the M K-phase inverters with a universal method, such that a direct-current (DC) power supply is converted into M K-phase alternating-current (AC) power supplies by the M K-phase inverters, and the M sets of symmetrical K-phase windings are powered on; and controlling the M power switch bridge arms, such that actual values of currents at the neutral points of the M sets of symmetrical K-phase windings each are maintained at a preset reference value, and an actual value of a current of each phase of winding is greater than or equal to 0 A, or the actual value of the current of each phase of winding is less than or equal to 0 A, thereby keeping the current of each phase of winding at a same direction, and enabling the SRM to enter the motor mode; and II: a generator mode: controlling the M power switch bridge arms, such that a power switch in each of the M power switch bridge arms is conducted; and controlling the M K-phase inverters, such that a power switch in each of the M K-phase inverters is conducted, wherein starting from the positive power terminal, an exciting current sequentially flows through the power switch conducted in the power switch bridge arm, one phase of winding in the symmetrical K-phase windings and the power switch conducted in the K-phase inverter to the negative power terminal, or sequentially flows through the power switch conducted in the K-phase inverter, the winding in the symmetrical K-phase windings and the power switch conducted in the power switch bridge arm to the negative power terminal, thereby enabling the SRM to enter an excitation state; and upon completion of excitation, enabling the SRM to rotate continuously, and turning off the M power switch bridge arms, such that the SRM enters a generating mode.
3 . The control strategy for driving an SRM according to claim 2 , wherein the universal method comprises a trapezoidal current driving method, a sinusoidal current control method, a field-oriented control method, a space vector control method, or a field weakening control method.
4 . The control strategy for driving an SRM according to claim 2 , wherein there are three methods for setting the reference value for the current at the neutral point: a first method is to directly set the reference value; a second method is to sum peaks of currents of K bridge arms of the K-phase inverter, and set a summed result as the reference value for the current at the neutral point; wherein, taking a three-phase inverter as an example, a set formula is as follows: i tail * = | i l ⁢ e ⁢ g ⁢ 1 | p ⁢ e ⁢ a ⁢ k + | i l ⁢ e ⁢ g ⁢ 2 | p ⁢ e ⁢ a ⁢ k + | i l ⁢ e ⁢ g ⁢ 3 | p ⁢ e ⁢ a ⁢ k wherein i tail * represents a reference value for a current at a neutral point, |i leg1 | peak represents a peak of a current of a first bridge arm of the three-phase inverter, |i leg2 | peak represents a peak of a current of a second bridge arm of the three-phase inverter, and |i leg3 | peak represents a peak of a current of a third bridge arm of the three-phase inverter; and a third method is to sum absolute values of reference values of amplitudes of the currents of the K bridge arms of the K-phase inverter, multiply a summed result by 1.5, and set a resulting product as the reference value for the current at the neutral point; wherein, taking the three-phase inverter as an example, a set formula is as follows: i tail * = 1 .5 ( | i a * | + | i b * | + | i c * | ) wherein i tail * represents the reference value for the current at the neutral point, i a * represents a reference value of an amplitude of the current of the first bridge arm of the three-phase inverter, i b * represents a reference value of an amplitude of the current of the second bridge arm of the three-phase inverter, and i c * represents a reference value of an amplitude of the current of the third bridge arm of the three-phase inverter.
5 . A topological circuit for driving a switched reluctance motor (SRM), comprising: an SRM, an additional bridge arm, and N inverter bridge arms, N being a positive integer, and N≥2, wherein the SRM comprises N phases of windings connected in a star configuration; the additional bridge arm comprises a freewheeling diode (FWD) and a power switch that are connected in series; a positive input terminal of the additional bridge arm is connected to a positive power terminal; a negative input terminal of the additional bridge arm is connected to a negative power terminal; and a midpoint of the additional bridge arm is connected to a neutral point for the N phases of windings; and positive input terminals of the N inverter bridge arms are connected to the positive power terminal; negative input terminals of the N inverter bridge arms are connected to the negative power terminal; midpoints of the N inverter bridge arms are connected to lead-out terminals of the N phases of windings in one-to-one correspondence; and the N inverter bridge arms jointly constitute an N-phase inverter.
6 . The topological circuit for driving an SRM according to claim 5 , wherein a cathode of the FWD of the additional bridge arm serves as the positive input terminal of the additional bridge arm; an anode of the FWD of the additional bridge arm is connected to a drain of the power switch of the additional bridge arm; and a source of the power switch of the additional bridge arm serves as the negative input terminal of the additional bridge arm.
7 . The topological circuit for driving an SRM according to claim 6 , wherein if N=3, a control strategy based on the topological circuit comprises: I: a three-phase conduction mode: conducting the power switch of the additional bridge arm to three-phase windings, such that the SRM enters the three-phase conduction mode, wherein in the three-phase conduction mode, a three-phase inverter is controlled with a universal method, such that upper power switches of three inverter bridge arms are conducted alternately, and when an upper power switch of one inverter bridge arm is conducted, lower power switches of the other two inverter bridge arms are conducted, or lower power switches of the three inverter bridge arms are conducted alternately, and when a lower power switch of one inverter bridge arm is conducted, upper power switches of the other two inverter bridge arms are conducted; and taking that an upper power switch of an inverter bridge arm A, a lower power switch of an inverter bridge arm B, and a lower power switch of an inverter bridge arm C are conducted at the same time as an example, an excitation path and a freewheeling path are respectively as follows: in the excitation path, starting from the positive power terminal, an exciting current sequentially flows through the upper power switch of the inverter bridge arm A and a phase-A winding to a neutral point for the three-phase windings, then flows through the power switch of the additional bridge arm to the negative power terminal in a first path, sequentially flows through a phase-B winding and the lower power switch of the inverter bridge arm B to the negative power terminal in a second path, and sequentially flows through a phase-C winding and the lower power switch of the inverter bridge arm C to the negative power terminal; and in the freewheeling path, starting from the negative power terminal, a freewheeling current sequentially flows through a parasitic diode of a lower power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings, then flows through the FWD of the additional bridge arm to the positive power terminal in a first path, sequentially flows through the phase-B winding and a parasitic diode of an upper power switch of the inverter bridge arm B to the positive power terminal in a second path, and sequentially flows through the phase-C winding and a parasitic diode of an upper power switch of the inverter bridge arm C to the positive power terminal in a third path; II: a two-phase conduction mode: conducting the power switch of the additional bridge arm to two-phase windings, such that the SRM enters the two-phase conduction mode, wherein in the two-phase conduction mode, the three-phase inverter is controlled with the universal method, such that the upper power switches of three inverter bridge arms are conducted alternately, and when an upper power switch of one inverter bridge arm is conducted, a lower power switch of another inverter bridge arm is conducted; and taking that the upper power switch of the inverter bridge arm A and the lower power switch of the inverter bridge arm B are conducted at the same time as an example, an excitation path, a freewheeling path, and two demagnetization paths are respectively as follows: in the excitation path, starting from the positive power terminal, an exciting current sequentially flows through the upper power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings, then flows through the power switch of the additional bridge arm to the negative power terminal in a first path, and sequentially flows through the phase-B winding and the lower power switch of the inverter bridge arm B to the negative power terminal in a second path; in the freewheeling path, starting from the negative power terminal, a freewheeling current sequentially flows through the parasitic diode of the lower power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings, then flows through the FWD of the additional bridge arm to the positive power terminal in a first path, and sequentially flows through the phase-B winding and the parasitic diode of the upper power switch of the inverter bridge arm B to the positive power terminal in a second path; in a first demagnetization path, starting from the negative power terminal, a demagnetizing current sequentially flows through the parasitic diode of the lower power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings, then flows through the power switch of the additional bridge arm to the negative power terminal in a first path, and sequentially flows through the phase-B winding and the lower power switch of the inverter bridge arm B to the negative power terminal in a second path; and in a second demagnetization path, starting from the positive power terminal, a demagnetizing current sequentially flows through the upper power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings, then flows through the FWD of the additional bridge arm to the positive power terminal in a first path, and sequentially flows through the phase-B winding and the parasitic diode of the upper power switch of the inverter bridge arm B to the positive power terminal in a second path; and III: a single-phase conduction mode: conducting the power switch of the additional bridge arm to a single-phase winding, such that the SRM enters the single-phase conduction mode, wherein in the single-phase conduction mode, the three-phase inverter is controlled with the universal method, such that the upper power switches of three inverter bridge arms are conducted alternately; and taking that the upper power switch of the inverter bridge arm A is conducted as an example, an excitation path and a freewheeling path are respectively as follows: in the excitation path, starting from the positive power terminal, an exciting current sequentially flows through the upper power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings, and then flows through the power switch of the additional bridge arm to the negative power terminal; and in the freewheeling path, starting from the negative power terminal, a freewheeling current sequentially flows through the parasitic diode of the lower power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings, and then flows through the FWD of the additional bridge arm to the positive power terminal.
8 . The topological circuit for driving an SRM according to claim 5 , wherein a drain of the power switch of the additional bridge arm serves as the positive input terminal of the additional bridge arm; a source of the power switch of the additional bridge arm is connected to a cathode of the FWD of the additional bridge arm; and an anode of the FWD of the additional bridge arm serves as the negative input terminal of the additional bridge arm.
9 . The topological circuit for driving an SRM according to claim 8 , wherein if N=3, a control strategy based on the topological circuit comprises: I: a three-phase conduction mode: conducting the power switch of the additional bridge arm to three-phase windings, such that the SRM enters the three-phase conduction mode, wherein in the three-phase conduction mode, a three-phase inverter is controlled with a universal method, such that upper power switches of three inverter bridge arms are conducted alternately, and when an upper power switch of one inverter bridge arm is conducted, lower power switches of the other two inverter bridge arms are conducted, or lower power switches of the three inverter bridge arms are conducted alternately, and when a lower power switch of one inverter bridge arm is conducted, upper power switches of the other two inverter bridge arms are conducted; and taking that an upper power switch of an inverter bridge arm A, a lower power switch of an inverter bridge arm B, and a lower power switch of an inverter bridge arm C are conducted at the same time as an example, an excitation path and a freewheeling path are respectively as follows: in the excitation path, starting from the positive power terminal, an exciting current sequentially flows through the upper power switch of the inverter bridge arm A and a phase-A winding to a neutral point for the three-phase windings in a first path, and flows through the power switch of the additional bridge arm to the neutral point for the three-phase windings in a second path; and then, the exciting current sequentially flows through a phase-B winding and the lower power switch of the inverter bridge arm B to the negative power terminal in a first path, and sequentially flows through a phase-C winding and the lower power switch of the inverter bridge arm C to the negative power terminal in a second path; and in the freewheeling path, starting from the negative power terminal, a freewheeling current sequentially flows through a parasitic diode of a lower power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings in a first path, and flows through the FWD of the additional bridge arm to the neutral point for the three-phase windings in a second path; and then, the freewheeling current sequentially flows through the phase-B winding and a parasitic diode of an upper power switch of the inverter bridge arm B to the positive power terminal in a first path, and sequentially flows through the phase-C winding and a parasitic diode of an upper power switch of the inverter bridge arm C to the positive power terminal in a second path; II: a two-phase conduction mode: conducting the power switch of the additional bridge arm to two-phase windings, such that the SRM enters the two-phase conduction mode, wherein in the two-phase conduction mode, the three-phase inverter is controlled with the universal method, such that the upper power switches of the three inverter bridge arms are conducted alternately, and when an upper power switch of one inverter bridge arm is conducted, a lower power switch of another inverter bridge arm is conducted; and taking that the upper power switch of the inverter bridge arm A and the lower power switch of the inverter bridge arm B are conducted at the same time as an example, an excitation path, a freewheeling path, and two demagnetization paths are respectively as follows: in the excitation path, starting from the positive power terminal, an exciting current sequentially flows through the upper power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings in a first path, flows through the power switch of the additional bridge arm to the neutral point for the three-phase windings in a second path, and then sequentially flows through the phase-B winding and the lower power switch of the inverter bridge arm B to the negative power terminal; and in the freewheeling path, starting from the negative power terminal, a freewheeling current sequentially flows through the parasitic diode of the lower power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings in a first path, flows through the FWD of the additional bridge arm to the neutral point for the three-phase windings in a second path, and then sequentially flows through the phase-B winding and the parasitic diode of the upper power switch of the inverter bridge arm B to the positive power terminal; in a first demagnetization path, starting from the negative power terminal, a demagnetizing current sequentially flows through the parasitic diode of the lower power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings in a first path, flows through the FWD of the additional bridge arm to the neutral point for the three-phase windings in a second path, and then sequentially flows through the phase-B winding and the lower power switch of the inverter bridge arm B to the negative power terminal; and in a second demagnetization path, starting from the positive power terminal, a demagnetizing current sequentially flows through the upper power switch of the inverter bridge arm A and the phase-A winding to the neutral point for the three-phase windings in a first path, flows through the power switch of the additional bridge arm to the neutral point for the three-phase windings in a second path, and then sequentially flows through the phase-B winding and the parasitic diode of the upper power switch of the inverter bridge arm B to the positive power terminal; and III: a single-phase conduction mode: conducting the power switch of the additional bridge arm to a single-phase winding, such that the SRM enters the single-phase conduction mode, wherein in the single-phase conduction mode, the three-phase inverter is controlled with the universal method, such that the lower power switches of the three inverter bridge arms are conducted alternately; and taking that the lower power switch of the inverter bridge arm B is conducted as an example, an excitation path and a freewheeling path are respectively as follows: in the excitation path, starting from the positive power terminal, an exciting current flows through the power switch of the additional bridge arm to the neutral point for the three-phase windings, and then sequentially flows through the phase-B winding and the lower power switch of the inverter bridge arm B to the negative power terminal; and in the freewheeling path, starting from the negative power terminal, a freewheeling current flows through the FWD of the additional bridge arm to the neutral point for the three-phase windings, and then sequentially flows through the phase-B winding and the parasitic diode of the upper power switch of the inverter bridge arm B to the positive power terminal.
10 . The control strategy for driving an SRM according to claim 7 , wherein the universal method comprises a trapezoidal current driving method, a sinusoidal current control method, a field-oriented control method, a space vector control method, or a field weakening control method.
11 . The control strategy for driving an SRM according to claim 9 , wherein the universal method comprises a trapezoidal current driving method, a sinusoidal current control method, a field-oriented control method, a space vector control method, or a field weakening control method.

Description

CROSS REFERENCE TO RELATED APPLICATION The present application claims priority to the Chinese Patent Application No. 202411550408.6, filed with the China National Intellectual Property Administration on Nov. 1, 2024, and entitled “TAIL-TYPE TOPOLOGICAL CIRCUIT AND CONTROL STRATEGY FOR DRIVING SWITCHED RELUCTANCE MOTOR (SRM)”, and the Chinese Patent Application No. 202510915721.3, filed with the China National Intellectual Property Administration on Jul. 3, 2025, and entitled “SHORT-TAIL TOPOLOGICAL CIRCUIT AND CONTROL STRATEGY FOR DRIVING SWITCHED RELUCTANCE MOTOR (SRM)”, which are incorporated herein by reference in their entirety. TECHNICAL FIELD The present disclosure relates to the technical field of driving control on switched reluctance motors (SRMs), and in particular to a topological circuit and control strategy for driving an SRM. BACKGROUND Switched reluctance motors (SRMs), as typical rare-earth-free motors, avoid the use of rare-earth permanent magnetic materials in the manufacturing process, reducing the manufacturing cost, and eliminating the demagnetization risk of the permanent magnetic materials in extreme operating conditions. Compared with such rare-earth-free motors as induction motors and synchronous reluctance motors, the SRMs feature a simple rotor structure, high strength, and low cost, making them more suitable for high temperatures, high pressures, vacuum environments, low temperatures, high-frequency vibration, and other extreme operating conditions. The conventional asymmetrical half-bridge power converter circuit and the modular converter circuit are two main types of driving control circuits for the SRMs at present. For the conventional asymmetrical half-bridge power converter circuit, asymmetrical half-bridge circuits are respectively connected to two terminals of each winding. The asymmetrical half-bridge circuits are used to perform unipolar excitation on the winding, thereby generating a unidirectional pulsed winding current. For the modular converter circuit, an additional bridge arm composed of two power switches is connected to a neutral point for three-phase windings. The additional bridge arm and the inverter bridge arm connected to the other terminal of each winding jointly constitute an H-bridge circuit. The H-bridge circuit is used to perform bipolar excitation on each winding, thereby generating a bidirectional pulsed winding current. However, the above two types of driving control circuits suffer from the following problems in actual application: Severe fluctuations will occur during commutation, resulting in large torque ripples of the SRMs. On the other hand, all control strategies lack control over axial and radial torque components, causing large noise of the SRMs in axial and radial directions. Due to the above problems, the SRMs exhibit poor operation performance. SUMMARY An objective of the present disclosure is to provide a topological circuit and control strategy for driving an SRM. The present disclosure can effectively reduce torque ripples and noise generated by the SRM, and improve the operating performance of the SRM. To achieve the above objective, the present disclosure provides the following technical solutions: According to a first aspect, the present disclosure provides a topological circuit for driving an SRM. The topological circuit for driving an SRM includes an SRM, a capacitor (C), M power switch bridge arms, and M K-phase inverters, M and K each being a positive integer, and K≥2, where the SRM has an N-phase winding structure, N=M×K; every K phases of windings form an independent set of symmetrical K-phase windings; and the symmetrical K-phase windings in each set of symmetrical K-phase windings are connected in a star configuration;two terminals of the capacitor (C) are respectively connected to a positive power terminal and a negative power terminal;positive input terminals of the M power switch bridge arms are connected to the positive power terminal; negative input terminals of the M power switch bridge arms are connected to the negative power terminal; and midpoints of the M power switch bridge arms are connected to neutral points of M sets of symmetrical K-phase windings in one-to-one correspondence; andpositive input terminals of the M K-phase inverters are connected to the positive power terminal; negative input terminals of the M K-phase inverters are connected to the negative power terminal; and K output terminals of the M K-phase inverters are connected to lead-out terminals of the M sets of symmetrical K-phase windings in one-to-one correspondence. According to a second aspect, the present disclosure further provides a control strategy for driving an SRM. The control strategy for driving an SRM is realized based on the topological circuit for driving an SRM in the first aspect, and the control strategy for driving an SRM includes following control modes: I: A Motor Mode: controlling the M K-phase inverters with a universal meth