Research On Switched Reluctance Motor Without Electrolytic Capacitor Power Converter

Switched reluctance motor(SRM)has a broad application prospect due to its long service life,strong fault tolerance,and low cost.However,the electrolytic capacitor in the SRM power conversion circuit has a short life span,which is the equivalent of only half of the motor drive system’s lifespan,so the existence of the electrolytic capacitor severely limits the development trend of the long life of the SRM drive system.Therefore,how to remove the electrolytic capacitor from the SRM power conversion circuit with single-phase input and three-phase output is an urgent problem.Because the control of the electrolytic capacitor SRM power conversion circuit is based on the boost PFC circuit,the power decoupling circuit and the three-phase inverter circuit,which can be controlled independently.The average current mode can be used to control the PFC circuit so that it has the function of correcting the power factor.By analyzing the ability of various topological circuits to absorb pulsating power,this paper uses a bidirectional Buck/Boost conversion circuit as a power decoupling circuit to absorb the pulsating power of the main circuit,and analyzes the different principles of its working in boost and buck schemes.During the conduction period of the SRM phase,the current hysteresis control strategy is adopted to control the drastic change of the energy on the SRM bus side.Using secondary shutdown and voltage hysteresis control strategy,the winding switches from zero point voltage freewheeling to negative voltage freewheeling state,and when the voltage is too high,it switches to zero voltage freewheeling state again to avoid rapid energy from flowing into the bus side during SRM demagnetization and to reduce the fluctuation range of bus voltage during SRM operation.A feedforward control strategy based on DC bus voltage fluctuations is proposed to control the power decoupling circuit to absorb the pulsating power generated in the main circuit to achieve the purpose of removing the electrolytic capacitor in the SRM power conversion circuit thereby increasing the life of the SRM drive system.On this basis,the feedforward control strategy is applied to the step-down power decoupling circuit.This scheme reduces the energy storage capacitor value and the device withstand voltage,and improves the system reliability.On the basis of theoretical analysis,using 2020 a matlab/simulink to build a simulation environment verifies the feasibility of the proposed control strategy.A power decoupling type SRM power conversion circuit controller with no electrolytic capacitor is designed with STM32F303 as the main control chip,and the rated power is 375 W.Two control strategies verified in MATLAB simulation environment are tested.The experimental results prove the effectiveness of the control strategy proposed in this paper.