Drive structure and control method of switched reluctance motor based on three-level inverter

Abstract

The invention discloses a switched reluctance motor drive topology based on a three-level inverter. The switched reluctance motor winding is combined with the three-level inverter, and the two-phase windings of the switched reluctance motor share a three-level inverter. The bridge arm of the transformer, the three-phase windings are connected end to end, and a new topology is obtained. Considering that the torque ripple is mainly generated in the commutation area, the traditional topology has larger ripple due to fewer working modes. However, the topology proposed in the present invention has 9 different modes when working in a single phase. In the two-phase overlapping area, there are 27 combined modes. Different working states correspond to different phase voltages. You can choose the optimal state and change the torque waveform according to your needs, which greatly improves the control freedom, reduces the torque ripple, and improves the torque. The advantage of the present invention is that a five-level circuit is proposed, so that each phase winding has good applicability and flexibility in high speed, low speed, excitation, demagnetization and the like. Effectively reduce the switching frequency, reduce the switching loss, increase the output torque of the switched reluctance motor, and smooth the torque ripple.

Description

technical field [0001] The invention relates to a switched reluctance motor drive system, in particular to a power conversion topology structure of a switched reluctance motor for an electric vehicle. Background technique [0002] A switched reluctance motor (Switched Reluctance Motor, SRM) only has windings on the stator, and the rotor is made of silicon steel sheets, which has a strong structure and low cost. It has a wide speed range, large starting torque, the torque direction is independent of the phase current, flexible control and high efficiency; it can regenerative braking and energy recovery, so it has gradually received attention in the field of electric vehicles. Now it has been used in the textile industry, aviation and household appliances. However, due to the double salient pole structure of the switched reluctance motor and the nonlinearity of the magnetic field, the torque ripple is relatively large, and the problems of vibration and noise are prominent. I...

AI Technical Summary

Problems solved by technology

[0007] 1. The existing topology only has three working states: power supply voltage excitation, reverse power supply voltage demagnetization, and zero-voltage freewheeling circuit. Changing the excitation voltage or demagnetization voltage can only be done by changing the power supply voltage, which cannot adapt to different working states. , different speed requirements

[0008] 2. The improved topology mainly increases the operating voltage by adding additional capacitors. Although the circuit operating mode is increased, the mutual interference between the front and rear phases of the motor greatly restricts the control flexibility.

[0009] 3. Some boost working states have too many restrictions and cannot be adjusted in real time according to control requirements

[0010] 4. The withstand voltage value of power devices is greatly improved, which increases the cost

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