A three-phase three-wire switched reluctance motor drive system, control method and application

Abstract

The present invention belongs to the field of magnetomechanical integration technology based on power electronics and microcomputer control technology, and discloses a three-phase three-wire switched reluctance motor drive system, control method and application. A switched reluctance motor stator is provided, and the switched reluctance motor stator has n stator salient poles, and each salient pole is wound with an independent salient pole coil; a three-phase full-bridge power conversion circuit composed of 6 switch tubes, and the three-phase full-bridge power conversion circuit is connected to a DC power supply; a controller controls the six switch tubes in the three-phase full-bridge power conversion circuit to be turned on or off. The present invention adopts a three-phase full-bridge power conversion circuit topology composed of 6 switch tubes, and the motor windings are connected in a star or delta connection according to a certain magnetic pole sequence and three wiring leads are drawn out. Compared with the structure using 12 switch tubes, the structural power components are reduced by half, which reduces the production cost; it is compatible with the current industrial common three-phase three-wire wiring method, which greatly improves the versatility and ease of use.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetomechanical integration based on power electronics and microcomputer control technology, and in particular relates to a three-phase three-wire switched reluctance motor drive system, a control method and an application thereof. Background Art

[0002] At present, the switched reluctance motor has been widely recognized by the industry due to its high reliability, good energy-saving effect and relatively low motor cost. For the topological structure of the power conversion circuit of the switched reluctance motor driver, the asymmetric bridge power conversion circuit is currently used for current conversion. The controller needs to use 12 switching tubes to independently control the three-phase winding of the motor. This control method requires the use of more power components, which increases the manufacturing cost. In this control method, the two ends of each phase winding need to be connected to the driver at the same time, so six cables are required. It is incompatible with the 3-phase 3-wire wiring method commonly used in the industry and has poor versatility. Because the phase windings are independently controlled, a large radial force will be generated at the moment of excitation shutdown, which will increase the motor noise.

[0003] Through the above analysis, the problems and defects of the prior art are as follows:

[0004] (1) The existing switched reluctance motor drive power conversion circuit requires the use of more power components, increasing manufacturing costs

[0005] (2) The existing switched reluctance motor drive power conversion circuit is not compatible with the three-phase three-wire wiring method currently used in the industry and has poor versatility.

[0006] (3) Since the phase windings are controlled independently, a large radial force will be generated at the moment the excitation is turned off, which will increase the motor noise.

[0007] The difficulty in solving the above problems and defects is: since the magnetic flux of the switched reluctance motor has highly nonlinear characteristics, the magnetic flux characteristics will change greatly with different excitation methods. When the above-mentioned three-wire winding excitation method is adopted, since the two-phase windings are excited at the same time to generate torque, the magnetic flux of the two-phase windings must be analyzed. The magnetic flux characteristics are greatly changed compared with the single-phase excitation control method of 6-wire control. The controller software needs to match the magnetic flux characteristics to achieve a better working state.

[0008] The significance of solving the above problems and defects is to reduce the manufacturing cost of the controller, improve ease of use, and improve the noise and vibration of the motor. Summary of the invention

[0009] In order to solve the problems existing in the prior art, the present invention provides a three-phase three-wire switched reluctance motor drive system, a control method and an application thereof.

[0010] The present invention is implemented as follows: a three-phase three-wire switched reluctance motor drive system is provided with a switched reluctance motor stator, the switched reluctance motor stator has n stator salient poles, and each salient pole is wound with an independent salient pole coil;

[0011] A three-phase full-bridge power conversion circuit composed of 6 switching tubes, wherein the three-phase full-bridge power conversion circuit is connected to a DC power supply;

[0012] A controller controls the six switch tubes in the three-phase full-bridge power conversion circuit to be turned on or off.

[0013] Furthermore, the ends of the four salient pole coils A1, A2, A3, and A4 evenly distributed on the circumference of the stator are connected together to form the A-phase winding of the motor.

[0014] Furthermore, when current flows into the positive terminal of coil A1 and out of the negative terminal of coil A4, the magnetic field generated by the current in the coil causes the magnetic poles of the corresponding four salient pole coils A1, A2, A3, and A4 to be arranged in N, S, N, S.

[0015] Furthermore, the ends of the four salient pole coils B1, B2, B3, and B4 adjacent to each salient pole coil in the A-phase winding are connected together to form the B-phase winding of the motor.

[0016] Furthermore, when current flows into the positive terminal of the B1 coil and out of the negative terminal of the B4 coil, the magnetic field generated by the current in the coil causes the corresponding four salient poles B1, B2, B3, and B4 to be arranged in N, S, N, S.

[0017] Furthermore, four salient pole coils C1, C2, C3, and C4 adjacent to each salient pole coil in the B-phase winding are connected together to form a C-phase winding of the motor.

[0018] Furthermore, when current flows into the positive terminal of coil C1 and out of the negative terminal of coil C4, the magnetic field generated by the current in the coil causes the magnetic poles of the corresponding four salient poles C1, C2, C3, and C4 to be arranged in N, S, N, S.

[0019] Further, the initial angle of the rotor corresponding to the stator of the switched reluctance motor is set to θ = 0°;

[0020] When 0°≤ θ ≤ 15°, the switch tubes Q1 and Q4 are controlled to be turned on;

[0021] When 15°≤ θ ≤ 30°, the switch tubes Q5 and Q4 are controlled to be turned on;

[0022] When 30°≤ θ ≤ 45°, the switch tubes Q5 and Q2 are controlled to be turned on;

[0023] When 45°≤ θ ≤ 60°, the switch tubes Q3 and Q2 are controlled to be turned on;

[0024] When 60°≤ θ ≤ 75°, the switch tubes Q3 and Q6 are controlled to be turned on;

[0025] When 75°≤ θ ≤ 90°, the switch tubes Q1 and Q6 are controlled to be turned on.

[0026] Another object of the present invention is to provide a control method for the three-phase three-wire switched reluctance motor drive system. The control program of the control method for the three-phase three-wire switched reluctance motor drive system outputs a control waveform according to the conduction control sequence with a mechanical angle of 90° as one electrical cycle, with a high level being on and a low level being off, to control the opening and closing of the corresponding switch tube. A continuous rotating reluctance torque is formed to make the motor run. The control program controls the magnitude of the phase current through a PWM modulation signal to control the motor speed.

[0027] Another object of the present invention is to provide a switched reluctance motor, which is equipped with the three-phase three-wire switched reluctance motor drive system.

[0028] Combining all the above technical solutions, the advantages and positive effects of the present invention are as follows:

[0029] First, the present invention adopts a three-phase full-bridge power conversion circuit topology composed of 6 switch tubes, and the motor windings are connected in a star or delta connection according to a certain magnetic pole sequence and three wires are drawn out. Compared with the structure using 12 switch tubes, this structure has half the number of power components, which reduces the production cost.

[0030] Second, the motor wiring is compatible with the current industrial common three-phase three-wire wiring method, which greatly improves the versatility and ease of use of the switched reluctance motor.

[0031] Third, the winding excitation method of the present invention is to alternately excite two phases out of the three phases at the same time. This excitation method only turns off one phase of the winding during phase switching, and the instantaneous back electromotive force generated is a negative 1 / 2 power supply voltage. In the traditional 6-wire excitation mode, the instantaneous back electromotive force generated when the winding excitation is turned off is a negative power supply voltage. This alleviates the sudden change of the radial force when the switch tube is turned off, and reduces the vibration and noise of the motor.

[0032] In the excitation mode of the present invention, the back electromotive force generated by the winding that is turned off during phase switching is half the power supply voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 It is a schematic diagram of a three-phase three-wire switched reluctance motor drive system provided by an embodiment of the present invention.

[0035] Figure 2 It is a schematic diagram of the circuit structure connection of a three-phase three-wire switched reluctance motor drive system provided by an embodiment of the present invention.

[0036] Figure 3 It is a schematic diagram of the timing logic waveform of the switch tube control provided by an embodiment of the present invention.

[0037] Figure 4 It is a schematic diagram of the rotor mechanical angle and the power-on state provided by an embodiment of the present invention.

[0038] Figure 5 It is a schematic diagram of the rotor mechanical angle and the power-on state provided by an embodiment of the present invention.

[0039] Figure 6 It is a schematic diagram of the rotor mechanical angle and the power-on state provided by an embodiment of the present invention.

[0040] Figure 7 It is a schematic diagram of the rotor mechanical angle and the power-on state provided by an embodiment of the present invention.

[0041] Figure 8 It is a schematic diagram of the rotor mechanical angle and the power-on state provided by an embodiment of the present invention.

[0042] Fig. 9 It is a schematic diagram of the rotor mechanical angle and the power-on state provided by an embodiment of the present invention.

[0043] Figure 1 and Figure 2 In the figure: 1. A-phase winding; 2. B-phase winding; 3. C-phase winding; 4. Switching tube; 5. Stator salient pole coil; 6. Stator salient pole; 7. Switching tube.

[0044] Fig.10 It is a schematic diagram of simulation results provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] In view of the problems existing in the prior art, the present invention provides a three-phase three-wire switched reluctance motor drive system, a control method and an application. The present invention is described in detail below in conjunction with the accompanying drawings.

[0047] The three-phase three-wire switched reluctance motor drive system is provided with a switched reluctance motor stator having a total of n stator salient poles, each salient pole being wound with an independent salient pole coil, and the present invention takes n=12 as an example.

[0048] The ends of the four salient pole coils A1, A2, A3, and A4 evenly distributed on the circumference of the stator are connected together to form the A-phase winding of the motor. The connection method of the above four salient pole coils A1, A2, A3, and A4 requires that when current flows into the positive end of the A1 coil and flows out of the negative end of the A4 coil, the magnetic field generated by the current in the coil makes the magnetic poles of the corresponding four salient poles A1, A2, A3, and A4 arranged in N, S, N, S.

[0049] The ends of the four salient pole coils B1, B2, B3, and B4 adjacent to each salient pole coil in the above-mentioned A-phase winding are connected together to form the B-phase winding of the motor. Furthermore, the connection method of the above-mentioned four salient pole coils B1, B2, B3, and B4 requires that when a current flows into the positive end of the B1 coil and flows out of the negative end of the B4 coil, the magnetic field generated by the current in the coil causes the magnetic poles of the corresponding four salient poles B1, B2, B3, and B4 to be arranged in N, S, N, S.

[0050] The four salient pole coils C1, C2, C3, and C4 adjacent to each salient pole coil in the above-mentioned B-phase winding are connected together to form the C-phase winding of the motor. Furthermore, the connection method of the above-mentioned four salient pole coils C1, C2, C3, and C4 requires that when a current flows into the positive terminal of the C1 coil and flows out of the negative terminal of the C4 coil, the magnetic field generated by the current in the coil causes the magnetic poles of the corresponding four salient poles C1, C2, C3, and C4 to be arranged in N, S, N, S.

[0051] Connect the negative terminals of coils A4, B4, and C4 together (star connection), or connect the negative terminals of coils A4, B4, and C4 to the positive terminals of coils C1, A1, and B1 respectively (delta connection).

[0052] The present invention is provided with a three-phase full-bridge power conversion circuit composed of six switch tubes Q1-Q6, and the three-phase full-bridge power conversion circuit is connected to a DC power supply. The positive terminals of the coils A1, B1, and C1 are respectively connected to the three bridge arm center points of the three-phase full-bridge power conversion circuit by three motor wirings.

[0053] The present invention is provided with a controller, which controls the six switch tubes in the three-phase full bridge to be turned on or off. The controller is provided with a control program, which controls the motor winding to be energized or turned off at a certain angle and sequence according to the position information of the rotor position sensor.

[0054] Take 12-8 pole motor as an example:

[0055] 1) Set the two adjacent salient poles of the rotor to be aligned with the salient poles of the stator A and C phase windings, and set the rotor angle to the initial angle θ = 0°. Figure 4 As shown in the figure: when 0°≤ θ ≤ 15°, the control switch tubes Q1 and Q4 are turned on, the current flows into the A phase winding, and flows out of the B phase winding, and the conduction direction is AB. At this time, the A and B phase windings are excited, and the magnetic flux linkage magnetic resistance is minimized because the two adjacent salient poles of the rotor must be aligned with the stator salient poles of the A and B phases, and the rotor generates a counterclockwise magnetic resistance torque.

[0056] 2) If Figure 5 As shown in the figure, when 15°≤ θ ≤ 30°, the control switch tubes Q5 and Q4 are turned on, the current flows into the C phase winding, and flows out of the B phase winding, and the conduction direction is CB. At this time, the C and B phase windings are excited, and the magnetic flux linkage reluctance is minimized because the two adjacent salient poles of the rotor must be aligned with the stator salient poles of the C and B phases, and the rotor generates a counterclockwise reluctance torque.

[0057] 3) If Figure 6 As shown in the figure: when 30°≤ θ ≤ 45°, the control switch tubes Q5 and Q2 are turned on, the current flows into the C phase winding, and flows out of the A phase winding, and the conduction direction is CA. At this time, the C and A phase windings are excited, and the magnetic flux linkage magnetic resistance is minimized because the two adjacent salient poles of the rotor must be aligned with the stator salient poles of the C and A phases, and the rotor generates a counterclockwise magnetic resistance torque.

[0058] 4) If Figure 7 As shown in the figure: when 45°≤ θ ≤ 60°, the control switch tubes Q3 and Q2 are turned on, the current flows into the B phase winding, and flows out of the A phase winding, and the conduction direction is BA. At this time, the B and A phase windings are excited, and the magnetic flux linkage magnetic resistance is minimized because the two adjacent salient poles of the rotor must be aligned with the stator salient poles of the B and A phases, and the rotor generates a counterclockwise magnetic resistance torque.

[0059] 5) If Figure 8 As shown in the figure: when 60°≤ θ ≤ 75°, the control switch tubes Q3 and Q6 are turned on, the current flows into the B phase winding, and flows out of the C phase winding, and the conduction direction is BC. At this time, the B and C phase windings are excited, and the magnetic flux linkage magnetic resistance is minimized because the two adjacent salient poles of the rotor must be aligned with the stator salient poles of the B and C phases, and the rotor generates a counterclockwise magnetic resistance torque.

[0060] 6) If Fig. 9As shown: when 75°≤ θ ≤ 90°, the control switch tubes Q1 and Q6 are turned on, the current flows into the A phase winding, and flows out of the C phase winding, and the conduction direction is AC. At this time, the A and C phase windings are excited, and the magnetic flux linkage magnetic resistance is minimized because the two adjacent salient poles of the rotor must be aligned with the stator salient poles of the A and C phases, and the rotor generates a counterclockwise magnetic resistance torque.

[0061] The above steps only list one case of control logic. According to actual application, the same purpose can be achieved by adjusting the angle of the initial position.

[0062] like Figure 3 As shown: the control program outputs a control waveform according to the conduction control sequence with a mechanical angle of 90° as one electrical cycle. The high level is conduction and the low level is off, which controls the opening and closing of the corresponding switch tube. A continuous rotating reluctance torque is formed to make the motor run. The control program controls the size of the phase current through the PWM modulation signal to control the motor speed.

[0063] The technical effects of the present invention are described in detail below in conjunction with simulation.

[0064] The simulation results are as follows Fig.10 As shown in the figure, a working principle of A and B phase winding excitation is pointed out: the current flows into the A phase winding and flows out of the B phase winding, and the conduction direction is AB. At this time, the A and B two-phase windings are excited, and the magnetic flux always closes along the path with the smallest magnetic resistance. Therefore, when the rotor salient poles and the stator salient poles do not coincide, there will be magnetic resistance acting on the rotor and generating torque to make it tend to the position with the smallest magnetic resistance. Since the two adjacent salient poles of the rotor must be aligned with the stator salient poles of the A and B phases, the magnetic flux linkage magnetic resistance is minimized, and the rotor generates a counterclockwise magnetic resistance torque.

[0065] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0066] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A three-phase three-wire switched reluctance motor drive system, characterized in that: The three-phase three-wire switched reluctance motor drive system is provided with a switched reluctance motor stator, the switched reluctance motor stator has n stator salient poles, and each salient pole is wound with an independent salient pole coil; A three-phase full-bridge power conversion circuit composed of 6 switching tubes, wherein the three-phase full-bridge power conversion circuit is connected to a DC power supply; A controller, controlling the six switch tubes in the three-phase full-bridge power conversion circuit to turn on or off; Connect the ends of the four salient pole coils A1, A2, A3, and A4 evenly distributed on the circumference of the stator together to form the A-phase winding of the motor; When current flows into the positive end of coil A1 and out of the negative end of coil A4, the magnetic field generated by the current in the coil makes the magnetic poles of the corresponding four salient-pole coils A1, A2, A3, and A4 arranged in the order of N, S, N, and S. The ends of the four salient pole coils B1, B2, B3, and B4 adjacent to each salient pole coil in the A-phase winding are connected together to form the B-phase winding of the motor; when current flows into the positive end of the B1 coil and flows out of the negative end of the B4 coil, the magnetic field generated by the current in the coil makes the magnetic poles of the corresponding four salient poles B1, B2, B3, and B4 arranged in N, S, N, S; the four salient pole coils C1, C2, C3, and C4 adjacent to each salient pole coil in the B-phase winding are connected together to form the C-phase winding of the motor; When current flows into the positive end of coil C1 and out of the negative end of coil C4, the magnetic field generated by the current in the coil makes the magnetic poles of the corresponding four salient poles C1, C2, C3, and C4 arranged in N, S, N, S; A star connection method is adopted in which the negative terminals of coils A4, B4, and C4 are connected together, or a triangle connection method is adopted in which the negative terminals of coils A4, B4, and C4 are connected together with the positive terminals of coils C1, A1, and B1 respectively; the positive terminals of coils A1, B1, and C1 are respectively connected to the center points of the three bridge arms of the three-phase full-bridge power conversion circuit by three motor wirings; The initial angle of the rotor corresponding to the stator of the switched reluctance motor is set to θ=0°; When 0°≤θ≤15°, the switch tubes Q1 and Q4 are controlled to be turned on; When 15°≤θ≤30°, the switch tubes Q5 and Q4 are controlled to be turned on; When 30°≤θ≤45°, the switch tubes Q5 and Q2 are controlled to be turned on; When 45°≤θ≤60°, the switch tubes Q3 and Q2 are controlled to be turned on; When 60°≤θ≤75°, the switch tubes Q3 and Q6 are controlled to be turned on; When 75°≤θ≤90°, the switch tubes Q1 and Q6 are controlled to be turned on.

2. A control method for a three-phase three-wire switched reluctance motor drive system as claimed in claim 1, characterized in that: The control program of the control method of the three-phase three-wire switched reluctance motor drive system outputs a control waveform according to the conduction control sequence with a mechanical angle of 90° as one electrical cycle, with a high level being on and a low level being off, to control the opening and closing of the corresponding switch tube; a continuous rotating reluctance torque is formed to make the motor run; the control program controls the size of the phase current through the PWM modulation signal to achieve the purpose of controlling the motor speed.

3. A switched reluctance motor, characterized in that: The switched reluctance motor is equipped with the three-phase three-wire switched reluctance motor drive system according to claim 2.

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