Switching reluctance motor driving mechanism based on three-level inverter and control method thereof

Abstract

The invention discloses a switching reluctance motor driving topology based on a three-level inverter. The new topological structure is formed by combining windings of a switching reluctance motor with the three-level inverter, and sharing a bridge arm of the three-level inverter by two phase windings of the switching reluctance motor while three phase windings are connected in an end to end manner. Considering that torque ripples are mainly generated in a phase commutation region, the traditional typology has large ripples since the operating modes are few. The typology provided by the invention has 9 different modes in single-phase operation, has 27 combined modes in a two-phase overlapping region, has different operating states, can select the optimal state according to needs in correspondence to different phase voltages, changes torque waveforms, greatly improves control freedom degree, reduces torque ripple, and increases torque. The switching reluctance motor driving mechanism is advantageous in providing a five level circuit, so that each phase winding has good applicability and flexibility in the aspects of high speed, low speed, excitation and demagnetization, effectively reduces switching frequency, reduces switching loss, increases output torque of the switching reluctance motor, and smoothes the torque ripples.

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] The switched reluctance motor (Switched Reluctance Motor, SRM) only has windings for 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....

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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