Short-tail topology circuit suitable 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 short-tail topology circuit suitable for driving a switch reluctance motor and a control strategy. According to the invention, the problem that the motor generates loud noise in the axial direction and the radial direction due to the fact that the existing switch reluctance motor drive control circuit causes the motor to generate loud torque pulsation is solved. The invention discloses a short-tail topology circuit suitable for driving a switched reluctance motor. The short-tail topology circuit comprises the switched reluctance motor, an additional bridge arm and an N-phase inverter bridge arm, wherein a winding of the switched reluctance motor adopts an N-phase winding in star connection; the additional bridge arm is formed by connecting a fly-wheel diode and a power switch in series; the middle point of the additional bridge arm is connected with the neutral point of the N-phase winding; the middle points of the N-phase inverter bridge arms are connected with the leading-out ends of the N-phase windings in a one-to-one correspondence mode. And the N-phase inverter bridge arms jointly form an N-phase inverter. The invention is suitable for the fields of electric automobiles, agricultural machinery, heavy machinery, mining machinery, flight equipment, household appliances, military facilities and the like.

Description

Technical Field

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

[0002] The switched reluctance motor (SRM), a typical rare-earth-free motor, avoids the use of rare-earth permanent magnets in its manufacturing, reducing manufacturing costs while eliminating the risk of permanent magnet demagnetization under extreme operating conditions. Compared to induction motors and synchronous reluctance motors, which are also rare-earth-free motors, its rotor structure is simpler, stronger, and less expensive, making it more suitable for extreme operating conditions such as high temperature and high pressure, vacuum and low temperature, and high-frequency vibration. Therefore, theoretical analysis shows that the switched reluctance motor is an ideal drive system for applications such as electric vehicles, agricultural machinery, heavy machinery, mining machinery, aircraft equipment, household appliances, and military facilities, potentially increasing the lifespan of existing drive systems by at least 2 times.

[0003] At present, there are two main types of switch reluctance motor drive control circuits: one is the traditional asymmetric half-bridge power converter circuit, and the other is the module converter circuit. Among them, the traditional asymmetric half-bridge power converter circuit is to connect an asymmetric half-bridge circuit (such as Figure 1 As shown in Figure 2), an asymmetrical half-bridge circuit is used to excite each phase winding in a unipolar manner, generating a unidirectional pulse winding current (such as Figure 2 The modular converter circuit connects an additional bridge arm consisting of two power switches to the neutral point of the three-phase winding. The additional bridge arm and the inverter bridge arm connected to the other end of each phase winding together form an H-bridge circuit (as shown in Figure 3 As shown in Figure 2), the H-bridge circuit is used to perform bipolar excitation on each phase winding to generate a bidirectional pulse winding current (as shown in Figure 2). Figure 4 shown).

[0004] However, in practical applications, both the traditional asymmetric half-bridge power converter circuit and the modular converter circuit have the following problems: First, both the unidirectional pulse winding current and the bidirectional pulse winding current will fluctuate violently during commutation, thereby causing the motor to generate large torque pulsations. Second, both the traditional asymmetric half-bridge power converter circuit and the modular converter circuit have control strategies that do not include the axial and radial torque components in the control, thereby causing the motor to generate large noise in the axial and radial directions. Based on this, it is necessary to invent a short-tail topology circuit and control strategy suitable for driving a switched reluctance motor to solve the problem that the existing switched reluctance motor drive control circuit causes the motor to generate large torque pulsations and generates large noise in the axial and radial directions. Summary of the Invention

[0005] In order to solve the problem that the existing switched reluctance motor drive control circuit causes the motor to generate large torque pulsation and large noise in the axial and radial directions, the present invention provides a short-tail topology circuit and control strategy suitable for driving the switched reluctance motor.

[0006] The present invention is achieved by adopting the following technical solutions: A short-tail topology circuit suitable for driving a switched reluctance motor comprises a switched reluctance motor, an additional bridge arm, and an N-phase inverter bridge arm; N is a positive integer, and N≥2; Among them, the winding of the switched reluctance motor adopts an N-phase winding connected in a star shape; The additional bridge arm is composed of a freewheeling diode and a power switch in series; The positive input terminal of the additional bridge arm is connected to the positive power supply terminal; the negative input terminal of the additional bridge arm is connected to the negative power supply terminal; the midpoint of the additional bridge arm is connected to the neutral point of the N-phase winding; The positive input ends of the N-phase inverter bridge arms are all connected to the positive power supply end; the negative input ends of the N-phase inverter bridge arms are all connected to the negative power supply end; the midpoints of the N-phase inverter bridge arms are connected one-to-one with the lead ends of the N-phase windings; the N-phase inverter bridge arms together constitute an N-phase inverter.

[0007] Preferably, the cathode of the freewheeling diode of the additional bridge arm serves as the positive input terminal of the additional bridge arm, the anode of the freewheeling diode of the additional bridge arm is connected to the drain of the power switch of the additional bridge arm, and the source of the power switch of the additional bridge arm serves as the negative input terminal of the additional bridge arm.

[0008] When N=3, the control strategy based on this circuit includes: 1. Three-phase conduction mode: Controlling the power switches and three-phase windings of the additional bridge arms to conduct, so that the switched reluctance motor enters a three-phase conduction mode; in this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switches of the other two phase inverter bridge arms are conducted; or the lower power switches of the three-phase inverter bridge arms are alternately conducted, and when the lower power switch of one phase inverter bridge arm is conducted, the upper power switches of the other two phase inverter bridge arms are conducted; Taking the upper power switch of the A-phase inverter bridge arm, the lower power switch of the B-phase inverter bridge arm, and the lower power switch of the C-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the power switch of the additional bridge arm and returns to the negative power supply end. On the other hand, it flows through the B-phase winding and the lower power switch of the B-phase inverter bridge arm in sequence and returns to the negative power supply end. On the third hand, it flows through the C-phase winding and the lower power switch of the C-phase inverter bridge arm in sequence and returns to the negative power supply end. Freewheeling path: The freewheeling current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, and the A-phase winding in sequence, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply terminal. On the other hand, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm in sequence, and returns to the positive power supply terminal. On the third hand, it flows through the C-phase winding and the parasitic diode of the upper power switch of the C-phase inverter bridge arm in sequence, and returns to the positive power supply terminal. 2. Two-phase conduction mode: The power switches of the additional bridge arm and two of the phase windings are controlled to conduct, so that the switched reluctance motor enters a two-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switch of the other phase inverter bridge arm is conducted. Taking the upper power switch of the A-phase inverter bridge arm and the lower power switch of the B-phase inverter bridge arm as an example, the excitation path, freewheeling path, and two demagnetization paths are as follows: Excitation path: The excitation current starts from the positive power supply terminal, flows through the upper power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the power switch of the additional bridge arm and returns to the negative power supply terminal. On the other hand, it flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm, and returns to the negative power supply terminal. Freewheeling path: The freewheeling current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply terminal. On the other hand, it flows through the B-phase winding, the parasitic diode of the upper power switch of the B-phase inverter bridge arm, and returns to the positive power supply terminal. The first demagnetization path: The demagnetization current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, and the A-phase winding, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the power switch of the additional bridge arm and returns to the negative power supply terminal. On the other hand, it flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm, and returns to the negative power supply terminal. The second demagnetization path: The demagnetization current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply end. On the other hand, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm in sequence, and then returns to the positive power supply end. 3. Single-phase conduction mode: The power switch of the additional bridge arm and one of the phase windings are controlled to conduct, so that the switched reluctance motor enters a single-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arm are alternately conducted. Taking the upper power switch of the A-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply terminal, flows through the upper power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, it flows through the power switch of the additional bridge arm and returns to the negative power supply terminal. Freewheeling path: The freewheeling current starts from the negative power supply end, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply end.

[0009] Preferably, the drain of the power switch of the additional bridge arm serves as the positive input terminal of the additional bridge arm, the source of the power switch of the additional bridge arm is connected to the cathode of the freewheeling diode of the additional bridge arm, and the anode of the freewheeling diode of the additional bridge arm serves as the negative input terminal of the additional bridge arm.

[0010] When N=3, the control strategy based on this circuit includes: 1. Three-phase conduction mode: Controlling the power switches and three-phase windings of the additional bridge arms to conduct, so that the switched reluctance motor enters a three-phase conduction mode; in this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switches of the other two phase inverter bridge arms are conducted; or the lower power switches of the three-phase inverter bridge arms are alternately conducted, and when the lower power switch of one phase inverter bridge arm is conducted, the upper power switches of the other two phase inverter bridge arms are conducted; Taking the upper power switch of the A-phase inverter bridge arm, the lower power switch of the B-phase inverter bridge arm, and the lower power switch of the C-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. It also flows through the power switch of the additional bridge arm and reaches the neutral point of the three-phase winding. Then, it flows through the B-phase winding and the lower power switch of the B-phase inverter bridge arm in sequence, and then returns to the negative power supply end. It also flows through the C-phase winding and the lower power switch of the C-phase inverter bridge arm in sequence, and then returns to the negative power supply end. Freewheeling path: The freewheeling current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. On the other hand, it flows through the freewheeling diode of the additional bridge arm and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm in sequence, and then returns to the positive power supply terminal. On the other hand, it flows through the C-phase winding and the parasitic diode of the upper power switch of the C-phase inverter bridge arm in sequence, and then returns to the positive power supply terminal. 2. Two-phase conduction mode: The power switches of the additional bridge arm and two of the phase windings are controlled to conduct, so that the switched reluctance motor enters a two-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switch of the other phase inverter bridge arm is conducted. Taking the upper power switch of the A-phase inverter bridge arm and the lower power switch of the B-phase inverter bridge arm as an example, the excitation path, freewheeling path, and two demagnetization paths are as follows: Excitation path: The excitation current starts from the positive power supply terminal, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding, and then reaches the neutral point of the three-phase winding. It also flows through the power switch of the additional bridge arm and reaches the neutral point of the three-phase winding. It then flows through the B-phase winding and the lower power switch of the B-phase inverter bridge arm and returns to the negative power supply terminal. Freewheeling path: The freewheeling current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm and the A-phase winding, and then reaches the neutral point of the three-phase winding. On the other hand, it flows through the freewheeling diode of the additional bridge arm and reaches the neutral point of the three-phase winding. Then, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm, and returns to the positive power supply terminal. The first demagnetization path: The demagnetization current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. It also flows through the freewheeling diode of the additional bridge arm and reaches the neutral point of the three-phase winding. It then flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm, and returns to the negative power supply terminal. The second demagnetization path: The demagnetization current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. It also flows through the power switch of the additional bridge arm and reaches the neutral point of the three-phase winding. It then flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm in sequence, and then returns to the positive power supply end. 3. Single-phase conduction mode: The power switch of the additional bridge arm and one of the phase windings are controlled to conduct, so that the switched reluctance motor enters a single-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the lower power switches of the three-phase inverter bridge arm are alternately conducted. Taking the lower power switch of the B-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply terminal, flows through the power switch of the additional bridge arm, reaches the neutral point of the three-phase winding, then flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm, and returns to the negative power supply terminal; Freewheeling path: The freewheeling current starts from the negative power supply end, flows through the freewheeling diode of the additional bridge arm and reaches the neutral point of the three-phase winding, then flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm and returns to the positive power supply end.

[0011] Preferably, 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.

[0012] Compared with the existing switched reluctance motor drive control circuit, the present invention has the following advantages by constructing a new short-tail topology circuit and control strategy without changing the switched reluctance motor structure: First, the winding current generated by the present invention is not a pulsed winding current, but a continuous winding current ( Figure 23 Figure 2 shows the winding current waveforms when using trapezoidal current drive and space vector control. This allows for continuous winding current without drastic fluctuations during commutation, effectively reducing motor torque ripple. Furthermore, the control strategy of this invention incorporates both axial and radial torque components, effectively reducing motor noise in both directions.

[0013] The present invention effectively solves the problem that the existing switched reluctance motor drive control circuit causes the motor to generate large torque pulsations and large noise in the axial and radial directions. It is suitable for electric vehicles, agricultural machinery, heavy machinery, mining machinery, flight equipment, household appliances, military facilities and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is the schematic diagram of the traditional asymmetric half-bridge power converter circuit.

[0015] Figure 2 It is the waveform of unidirectional pulse winding current.

[0016] Figure 3 This is the schematic diagram of the module converter circuit.

[0017] Figure 4 It is the waveform diagram of bidirectional pulse winding current.

[0018] Figure 5 This is the first principle diagram of the short-tail topology circuit in the present invention.

[0019] Figure 6 This is the second principle diagram of the short-tail topology circuit in the present invention.

[0020] Figure 7 It is a schematic diagram of the excitation path in the three-phase conduction mode of the first control strategy in the present invention.

[0021] Figure 8 It is a schematic diagram of the freewheeling path in the three-phase conduction mode of the first control strategy in the present invention.

[0022] Figure 9 It is a schematic diagram of the excitation path in the two-phase conduction mode of the first control strategy in the present invention.

[0023] Figure 10 It is a schematic diagram of the freewheeling path in the two-phase conduction mode of the first control strategy in the present invention.

[0024] Figure 11 It is a schematic diagram of the first demagnetization path in the two-phase conduction mode of the first control strategy in the present invention.

[0025] Figure 12 It is a schematic diagram of the second demagnetization path in the two-phase conduction mode of the first control strategy in the present invention.

[0026] Figure 13 It is a schematic diagram of the excitation path in the single-phase conduction mode of the first control strategy in the present invention.

[0027] Figure 14 It is a schematic diagram of the freewheeling path in the single-phase conduction mode of the first control strategy in the present invention.

[0028] Figure 15 It is a schematic diagram of the excitation path in the three-phase conduction mode of the second control strategy in the present invention.

[0029] Figure 16 It is a schematic diagram of the freewheeling path in the three-phase conduction mode of the second control strategy in the present invention.

[0030] Figure 17It is a schematic diagram of the excitation path in the two-phase conduction mode of the second control strategy in the present invention.

[0031] Figure 18 It is a schematic diagram of the freewheeling path in the two-phase conduction mode of the second control strategy in the present invention.

[0032] Figure 19 It is a schematic diagram of the first demagnetization path in the two-phase conduction mode of the second control strategy in the present invention.

[0033] Figure 20 Schematic diagram of the second demagnetization path in the two-phase conduction mode of the second control strategy in the present invention.

[0034] Figure 21 It is a schematic diagram of the excitation path in the single-phase conduction mode of the second control strategy in the present invention.

[0035] Figure 22 It is a schematic diagram of the freewheeling path in the single-phase conduction mode of the second control strategy in the present invention.

[0036] Figure 23 This is a waveform diagram of the winding current when the trapezoidal current driving method and the space vector control method are adopted in the present invention.

[0037] Figure 24 It is a schematic diagram of the technical evolution path of the short-tail topology circuit in the present invention.

[0038] In the figure: the dotted arrow indicates the actual current direction of the winding. DETAILED DESCRIPTION Example 1

[0039] A short-tail topology circuit suitable for driving a switched reluctance motor comprises a switched reluctance motor, an additional bridge arm, and an N-phase inverter bridge arm; N is a positive integer, and N≥2; Among them, the winding of the switched reluctance motor adopts an N-phase winding connected in a star shape; The additional bridge arm is composed of a freewheeling diode and a power switch in series; The positive input terminal of the additional bridge arm is connected to the positive power supply terminal; the negative input terminal of the additional bridge arm is connected to the negative power supply terminal; the midpoint of the additional bridge arm is connected to the neutral point of the N-phase winding; The positive input ends of the N-phase inverter bridge arms are all connected to the positive power supply end; the negative input ends of the N-phase inverter bridge arms are all connected to the negative power supply end; the midpoints of the N-phase inverter bridge arms are connected one-to-one with the lead ends of the N-phase windings; the N-phase inverter bridge arms together constitute an N-phase inverter.

[0040] In this embodiment, the cathode of the freewheeling diode of the additional bridge arm serves as the positive input terminal of the additional bridge arm, the anode of the freewheeling diode of the additional bridge arm is connected to the drain of the power switch of the additional bridge arm, and the source of the power switch of the additional bridge arm serves as the negative input terminal of the additional bridge arm. Figure 5 shown.

[0041] When N=3, the control strategy based on this circuit includes: 1. Three-phase conduction mode: Controlling the power switches and three-phase windings of the additional bridge arms to conduct, so that the switched reluctance motor enters a three-phase conduction mode; in this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switches of the other two phase inverter bridge arms are conducted; or the lower power switches of the three-phase inverter bridge arms are alternately conducted, and when the lower power switch of one phase inverter bridge arm is conducted, the upper power switches of the other two phase inverter bridge arms are conducted; Taking the upper power switch of the A-phase inverter bridge arm, the lower power switch of the B-phase inverter bridge arm, and the lower power switch of the C-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the power switch of the additional bridge arm and returns to the negative power supply end. On the other hand, it flows through the B-phase winding and the lower power switch of the B-phase inverter bridge arm in sequence and returns to the negative power supply end. On the third hand, it flows through the C-phase winding and the lower power switch of the C-phase inverter bridge arm in sequence and returns to the negative power supply end. Figure 7 As shown; Freewheeling path: The freewheeling current starts from the negative power supply end, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply end. On the other hand, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm and returns to the positive power supply end. On the third hand, it flows through the C-phase winding and the parasitic diode of the upper power switch of the C-phase inverter bridge arm and returns to the positive power supply end. Figure 8 As shown; 2. Two-phase conduction mode: The power switches of the additional bridge arm and two of the phase windings are controlled to conduct, so that the switched reluctance motor enters a two-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switch of the other phase inverter bridge arm is conducted. Taking the upper power switch of the A-phase inverter bridge arm and the lower power switch of the B-phase inverter bridge arm as an example, the excitation path, freewheeling path, and two demagnetization paths are as follows: Excitation path: The excitation current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the power switch of the additional bridge arm and returns to the negative power supply end. On the other hand, it flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm, and returns to the negative power supply end. Figure 9 As shown; Freewheeling path: The freewheeling current starts from the negative power supply end, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply end. On the other hand, it flows through the B-phase winding, the parasitic diode of the upper power switch of the B-phase inverter bridge arm, and returns to the positive power supply end. Figure 10 As shown; The first demagnetization path: The demagnetization current starts from the negative power supply end, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the power switch of the additional bridge arm and returns to the negative power supply end. On the other hand, it flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm, and returns to the negative power supply end. Figure 11 As shown; The second demagnetization path: The demagnetization current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply end. On the other hand, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm in sequence and returns to the positive power supply end. Figure 12 As shown; 3. Single-phase conduction mode: The power switch of the additional bridge arm and one of the phase windings are controlled to conduct, so that the switched reluctance motor enters a single-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arm are alternately conducted. Taking the upper power switch of the A-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then it flows through the power switch of the additional bridge arm and returns to the negative power supply end. Figure 13 As shown; Freewheeling path: The freewheeling current starts from the negative power supply end, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply end. Figure 14shown.

[0042] 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. Example 2

[0043] A short-tail topology circuit suitable for driving a switched reluctance motor comprises a switched reluctance motor, an additional bridge arm, and an N-phase inverter bridge arm; N is a positive integer, and N≥2; Among them, the winding of the switched reluctance motor adopts an N-phase winding connected in a star shape; The additional bridge arm is composed of a freewheeling diode and a power switch in series; The positive input terminal of the additional bridge arm is connected to the positive power supply terminal; the negative input terminal of the additional bridge arm is connected to the negative power supply terminal; the midpoint of the additional bridge arm is connected to the neutral point of the N-phase winding; The positive input ends of the N-phase inverter bridge arms are all connected to the positive power supply end; the negative input ends of the N-phase inverter bridge arms are all connected to the negative power supply end; the midpoints of the N-phase inverter bridge arms are connected one-to-one with the lead ends of the N-phase windings; the N-phase inverter bridge arms together constitute an N-phase inverter.

[0044] In this embodiment, the drain of the power switch of the additional bridge arm serves as the positive input terminal of the additional bridge arm, the source of the power switch of the additional bridge arm is connected to the cathode of the freewheeling diode of the additional bridge arm, and the anode of the freewheeling diode of the additional bridge arm serves as the negative input terminal of the additional bridge arm. Figure 6 shown.

[0045] When N=3, the control strategy based on this circuit includes: 1. Three-phase conduction mode: Controlling the power switches and three-phase windings of the additional bridge arms to conduct, so that the switched reluctance motor enters a three-phase conduction mode; in this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switches of the other two phase inverter bridge arms are conducted; or the lower power switches of the three-phase inverter bridge arms are alternately conducted, and when the lower power switch of one phase inverter bridge arm is conducted, the upper power switches of the other two phase inverter bridge arms are conducted; Taking the upper power switch of the A-phase inverter bridge arm, the lower power switch of the B-phase inverter bridge arm, and the lower power switch of the C-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. On the other hand, it flows through the power switch of the additional bridge arm and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the B-phase winding and the lower power switch of the B-phase inverter bridge arm in sequence, and then returns to the negative power supply end. On the other hand, it flows through the C-phase winding and the lower power switch of the C-phase inverter bridge arm in sequence, and then returns to the negative power supply end. Figure 15 As shown; Freewheeling path: The freewheeling current starts from the negative power supply end. On the one hand, it flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm and the A-phase winding to reach the neutral point of the three-phase winding. On the other hand, it flows through the freewheeling diode of the additional bridge arm to reach the neutral point of the three-phase winding. Then, on the one hand, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm to return to the positive power supply end. On the other hand, it flows through the C-phase winding and the parasitic diode of the upper power switch of the C-phase inverter bridge arm to return to the positive power supply end. Figure 16 As shown; 2. Two-phase conduction mode: The power switches of the additional bridge arm and two of the phase windings are controlled to conduct, so that the switched reluctance motor enters a two-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switch of the other phase inverter bridge arm is conducted. Taking the upper power switch of the A-phase inverter bridge arm and the lower power switch of the B-phase inverter bridge arm as an example, the excitation path, freewheeling path, and two demagnetization paths are as follows: Excitation path: The excitation current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. On the other hand, it flows through the power switch of the additional bridge arm and reaches the neutral point of the three-phase winding. Then, it flows through the B-phase winding and the lower power switch of the B-phase inverter bridge arm in sequence and returns to the negative power supply end. Figure 17 As shown; Freewheeling path: The freewheeling current starts from the negative power supply end, and on the one hand, it flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm and the A-phase winding to reach the neutral point of the three-phase winding. On the other hand, it flows through the freewheeling diode of the additional bridge arm to reach the neutral point of the three-phase winding, and then flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm to return to the positive power supply end. Figure 18 As shown; The first demagnetization path: The demagnetization current starts from the negative power supply end, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm and the A-phase winding, and then reaches the neutral point of the three-phase winding. On the other hand, it flows through the freewheeling diode of the additional bridge arm and reaches the neutral point of the three-phase winding. Then it flows through the B-phase winding and the lower power switch of the B-phase inverter bridge arm and returns to the negative power supply end. Figure 19 As shown; The second demagnetization path: The demagnetization current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. On the other hand, it flows through the power switch of the additional bridge arm and reaches the neutral point of the three-phase winding. Then, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm in sequence, and then returns to the positive power supply end. Figure 20 As shown; 3. Single-phase conduction mode: The power switch of the additional bridge arm and one of the phase windings are controlled to conduct, so that the switched reluctance motor enters a single-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the lower power switches of the three-phase inverter bridge arm are alternately conducted. Taking the lower power switch of the B-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply end, flows through the power switch of the additional bridge arm and reaches the neutral point of the three-phase winding, then flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm and returns to the negative power supply end. Figure 21 As shown; Freewheeling path: The freewheeling current starts from the negative power supply end, flows through the freewheeling diode of the additional bridge arm, and reaches the neutral point of the three-phase winding. Then it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm and returns to the positive power supply end. Figure 22 shown.

[0046] 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.

[0047] The technical evolution path of the short tail topology circuit in the present invention is as follows Figure 24 As shown: Figure 24The initial concept of the present invention is to connect the three-phase windings of the switched reluctance motor in a star configuration, then connect the output terminals of the three-phase windings to a three-phase inverter. Simultaneously, the neutral point of the three-phase windings is connected to an inertial device (an inductor in the figure). A full-bridge circuit is connected across the inertial device to control the current flowing through it, thereby controlling the neutral-point current. This concept aims to achieve consistency in the direction of the current in each phase winding through this neutral-point current control, thereby achieving unipolar excitation of each phase winding.

[0048] Figure 24 b is based on Figure 24 The improvement idea of ​​a is due to Figure 24 The idea in a determines that the direction of the current flowing through the inertial device is always consistent, so Figure 24 The full-bridge circuit in a is improved to an asymmetric half-bridge circuit. This improvement can reduce the number of power switches in the circuit while still maintaining control over the direction of the neutral point current.

[0049] Figure 24 c is based on Figure 24 The improvement idea of ​​b is to Figure 24 The inertial device in b is eliminated, and the asymmetric half-bridge circuit is optimized into an additional bridge arm consisting of two power switches. This allows direct control of the neutral point current, thereby ensuring unipolar excitation of each phase winding, that is, ensuring that the current direction in each phase winding is always consistent.

[0050] Figure 24 d and Figure 24 e is based on Figure 24 The final evolution of c is the short tail topology circuit in this invention. Since the neutral point current direction is fixed, Figure 24 One of the power switches in the additional bridge arm in c will always be in the off state, and only its parasitic diode will produce freewheeling effect. Therefore, according to the different directions of the winding current, Figure 24 One of the power switches in the additional bridge arm in c is replaced with a freewheeling diode, further reducing the number of power switches and the complexity of circuit topology and control. Figure 24 The direction of the neutral point current in d is from right to left. Figure 24 The direction of the neutral point current in e is from left to right, the difference is: Figure 24 In d, the winding current comes from the upper half of the inverter bridge arm, and the additional bridge arm passively controls the neutral point current; Figure 24 In Figure e, the winding current comes from the additional bridge arm. At this time, the power switch of the additional bridge arm actively controls the neutral point current. Figure 24 d and Figure 24The basic control scheme and operating principle of e are the same, the difference lies in the control process of the neutral point current and the excitation source of the winding current.

[0051] The advantages of the short-tail topology circuit in the present invention are: a freewheeling diode or a circuit that achieves the same function is used to replace the power switch that does not achieve the switching function, which reduces the hardware cost of the additional bridge arm and further improves the integration of the entire drive circuit. At the same time, it reduces the power switch device loss of the additional bridge arm. Only a single power switch needs to be controlled in the additional bridge arm, which reduces the calculation burden of the controller chip and simplifies the control process of the drive circuit. At the same time, the additional bridge arm can still cooperate with the three-phase inverter to perform unipolar excitation on each phase winding, and can simultaneously ensure the unidirectionality of the winding current in the motor mode and the generator mode, expanding the range of control methods that the circuit is adapted to. In the motor mode, the direction of the neutral point current is adjusted and the amplitude of the neutral point current is limited by controlling the power switch of the additional bridge arm. The freewheeling diode of the additional bridge arm plays a freewheeling role and limits the direction of the neutral point current. In generator mode, when the power switch of the additional bridge arm is turned on, it cooperates with the three-phase inverter to excite the windings of each phase. When the power switch of the additional bridge arm is turned off, the current of the excited winding is applied to the generator load through the freewheeling diode of the additional bridge arm, realizing the unidirectional current power generation process.

[0052] 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 short-tail topology circuit suitable for driving a switched reluctance motor, characterized in that: It includes a switched reluctance motor, an additional bridge arm, and an N-phase inverter bridge arm; N is a positive integer, and N≥2; Among them, the winding of the switched reluctance motor adopts an N-phase winding connected in a star shape; The additional bridge arm is composed of a freewheeling diode and a power switch in series; The positive input terminal of the additional bridge arm is connected to the positive power supply terminal; the negative input terminal of the additional bridge arm is connected to the negative power supply terminal; the midpoint of the additional bridge arm is connected to the neutral point of the N-phase winding; The positive input ends of the N-phase inverter bridge arms are all connected to the positive power supply end; the negative input ends of the N-phase inverter bridge arms are all connected to the negative power supply end; the midpoints of the N-phase inverter bridge arms are connected one-to-one with the lead ends of the N-phase windings; the N-phase inverter bridge arms together constitute an N-phase inverter.

2. The short-tail topology circuit suitable for driving a switched reluctance motor according to claim 1, characterized in that: The cathode of the freewheeling diode of the additional bridge arm serves as the positive input terminal of the additional bridge arm, the anode of the freewheeling diode of the additional bridge arm is connected to the drain of the power switch of the additional bridge arm, and the source of the power switch of the additional bridge arm serves as the negative input terminal of the additional bridge arm.

3. The short-tail topology circuit suitable for driving a switched reluctance motor according to claim 2, characterized in that: When N=3, the control strategy based on this circuit includes:

1. Three-phase conduction mode: Controlling the power switches and three-phase windings of the additional bridge arms to conduct, so that the switched reluctance motor enters a three-phase conduction mode; in this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switches of the other two phase inverter bridge arms are conducted; or the lower power switches of the three-phase inverter bridge arms are alternately conducted, and when the lower power switch of one phase inverter bridge arm is conducted, the upper power switches of the other two phase inverter bridge arms are conducted; Taking the upper power switch of the A-phase inverter bridge arm, the lower power switch of the B-phase inverter bridge arm, and the lower power switch of the C-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the power switch of the additional bridge arm and returns to the negative power supply end. On the other hand, it flows through the B-phase winding and the lower power switch of the B-phase inverter bridge arm in sequence and returns to the negative power supply end. On the third hand, it flows through the C-phase winding and the lower power switch of the C-phase inverter bridge arm in sequence and returns to the negative power supply end. Freewheeling path: The freewheeling current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, and the A-phase winding in sequence, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply terminal. On the other hand, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm in sequence, and returns to the positive power supply terminal. On the third hand, it flows through the C-phase winding and the parasitic diode of the upper power switch of the C-phase inverter bridge arm in sequence, and returns to the positive power supply terminal.

2. Two-phase conduction mode: The power switches of the additional bridge arm and two of the phase windings are controlled to conduct, so that the switched reluctance motor enters a two-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switch of the other phase inverter bridge arm is conducted. Taking the upper power switch of the A-phase inverter bridge arm and the lower power switch of the B-phase inverter bridge arm as an example, the excitation path, freewheeling path, and two demagnetization paths are as follows: Excitation path: The excitation current starts from the positive power supply terminal, flows through the upper power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the power switch of the additional bridge arm and returns to the negative power supply terminal. On the other hand, it flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm, and returns to the negative power supply terminal. Freewheeling path: The freewheeling current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply terminal. On the other hand, it flows through the B-phase winding, the parasitic diode of the upper power switch of the B-phase inverter bridge arm, and returns to the positive power supply terminal. The first demagnetization path: The demagnetization current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, and the A-phase winding, and reaches the neutral point of the three-phase winding. Then, it flows through the power switch of the additional bridge arm and returns to the negative power supply terminal. On the other hand, it flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm, and returns to the negative power supply terminal. The second demagnetization path: The demagnetization current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply end. On the other hand, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm in sequence, and then returns to the positive power supply end.

3. Single-phase conduction mode: The power switch of the additional bridge arm and one of the phase windings are controlled to conduct, so that the switched reluctance motor enters a single-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arm are alternately conducted. Taking the upper power switch of the A-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply terminal, flows through the upper power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then, it flows through the power switch of the additional bridge arm and returns to the negative power supply terminal. Freewheeling path: The freewheeling current starts from the negative power supply end, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. Then it flows through the freewheeling diode of the additional bridge arm and returns to the positive power supply end.

4. The short-tail topology circuit suitable for driving a switched reluctance motor according to claim 1, characterized in that: The drain of the power switch of the additional bridge arm serves as the positive input terminal of the additional bridge arm, the source of the power switch of the additional bridge arm is connected to the cathode of the freewheeling diode of the additional bridge arm, and the anode of the freewheeling diode of the additional bridge arm serves as the negative input terminal of the additional bridge arm.

5. The short-tail topology circuit suitable for driving a switched reluctance motor according to claim 4, characterized in that: When N=3, the control strategy based on this circuit includes:

1. Three-phase conduction mode: Controlling the power switches and three-phase windings of the additional bridge arms to conduct, so that the switched reluctance motor enters a three-phase conduction mode; in this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switches of the other two phase inverter bridge arms are conducted; or the lower power switches of the three-phase inverter bridge arms are alternately conducted, and when the lower power switch of one phase inverter bridge arm is conducted, the upper power switches of the other two phase inverter bridge arms are conducted; Taking the upper power switch of the A-phase inverter bridge arm, the lower power switch of the B-phase inverter bridge arm, and the lower power switch of the C-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. It also flows through the power switch of the additional bridge arm and reaches the neutral point of the three-phase winding. Then, it flows through the B-phase winding and the lower power switch of the B-phase inverter bridge arm in sequence, and then returns to the negative power supply end. It also flows through the C-phase winding and the lower power switch of the C-phase inverter bridge arm in sequence, and then returns to the negative power supply end. Freewheeling path: The freewheeling current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. On the other hand, it flows through the freewheeling diode of the additional bridge arm and reaches the neutral point of the three-phase winding. Then, on the one hand, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm in sequence, and then returns to the positive power supply terminal. On the other hand, it flows through the C-phase winding and the parasitic diode of the upper power switch of the C-phase inverter bridge arm in sequence, and then returns to the positive power supply terminal.

2. Two-phase conduction mode: The power switches of the additional bridge arm and two of the phase windings are controlled to conduct, so that the switched reluctance motor enters a two-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the upper power switches of the three-phase inverter bridge arms are alternately conducted, and when the upper power switch of one phase inverter bridge arm is conducted, the lower power switch of the other phase inverter bridge arm is conducted. Taking the upper power switch of the A-phase inverter bridge arm and the lower power switch of the B-phase inverter bridge arm as an example, the excitation path, freewheeling path, and two demagnetization paths are as follows: Excitation path: The excitation current starts from the positive power supply terminal, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding, and then reaches the neutral point of the three-phase winding. It also flows through the power switch of the additional bridge arm and reaches the neutral point of the three-phase winding. It then flows through the B-phase winding and the lower power switch of the B-phase inverter bridge arm and returns to the negative power supply terminal. Freewheeling path: The freewheeling current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm and the A-phase winding, and then reaches the neutral point of the three-phase winding. On the other hand, it flows through the freewheeling diode of the additional bridge arm and reaches the neutral point of the three-phase winding. Then, it flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm, and returns to the positive power supply terminal. The first demagnetization path: The demagnetization current starts from the negative power supply terminal, flows through the parasitic diode of the lower power switch of the A-phase inverter bridge arm, the A-phase winding, and reaches the neutral point of the three-phase winding. It also flows through the freewheeling diode of the additional bridge arm and reaches the neutral point of the three-phase winding. It then flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm, and returns to the negative power supply terminal. The second demagnetization path: The demagnetization current starts from the positive power supply end, flows through the upper power switch of the A-phase inverter bridge arm and the A-phase winding in sequence, and then reaches the neutral point of the three-phase winding. It also flows through the power switch of the additional bridge arm and reaches the neutral point of the three-phase winding. It then flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm in sequence, and then returns to the positive power supply end.

3. Single-phase conduction mode: The power switch of the additional bridge arm and one of the phase windings are controlled to conduct, so that the switched reluctance motor enters a single-phase conduction mode. In this mode, a common method is used to control the three-phase inverter so that the lower power switches of the three-phase inverter bridge arm are alternately conducted. Taking the lower power switch of the B-phase inverter bridge arm as an example, the excitation path and the freewheeling path are as follows: Excitation path: The excitation current starts from the positive power supply terminal, flows through the power switch of the additional bridge arm, reaches the neutral point of the three-phase winding, then flows through the B-phase winding, the lower power switch of the B-phase inverter bridge arm, and returns to the negative power supply terminal; Freewheeling path: The freewheeling current starts from the negative power supply end, flows through the freewheeling diode of the additional bridge arm and reaches the neutral point of the three-phase winding, then flows through the B-phase winding and the parasitic diode of the upper power switch of the B-phase inverter bridge arm and returns to the positive power supply end.

6. A short-tail topology circuit suitable for driving a switched reluctance motor according to claim 3 or 5, 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.

Images