Switched reluctance motor(SRM)has the advantages of simple structure,flexible control methods and low cost,and is valuable in the fields of electric vehicles and wind power generation.Obtaining the rotor angle of the motor is the prerequisite for driving an SRM,which is generally achieved by a position sensor on the motor.However,the sensor cannot work for a long time in the harsh environment such as high temperature and dust,which reduces the reliability of the system.Therefore,it is important to study the control technology without position sensor.In this paper,a four-phase 8/6 SRM was used as the object to study the positionless control strategy of switched reluctance drive(SRD)and switched reluctance generator(SRG).Firstly,The nonlinear relationship between the magnetic chain and torque of the SRM was studied from the perspective of nonlinear modelling.The nonlinear simulation model of the SRM winding and the electromechanical model were built in Simulink based on the results of the nonlinear modelling.Then,a position sensor-free control strategy based on the inductive partitioning compensation was proposed,and the starting phase was determined by comparing the four-phase current peaks with the injection of high-frequency pulses in the stationary phase.For the current reduction of original inductor partitioned positionless control,the position interval of the inductor intersection was compensated in order to achieve smooth chopper ground operation.The simulation results for single-phase conduction and single-phase and two-phase alternating conduction conditions were obtained with a position-free simulation model,and the actual rotor angle of the motor was compared with the estimated angle,which verified the feasibility of the SRD position-free control strategy based on the inductance partitioning compensation strategy.Subsequently,an SRG positionless control strategy based on full conduction chopping was proposed.A small chopper current was set for the interval where each phase of the generator winding should be switched off to ensure that the generator was in the fully chopped conduction state,and the full chopper current was collected for the position-free control.The feasibility of the proposed strategy was verified in Simulink using the SRG position-free simulation model.In the end,experiments including the start-up phase judgement of the SRD in the stationary phase,the position-free control of the SRD,the closed-loop speed of the SRD and on the position-free control of the SRG were carried out on the position-free experimental platform.The experimental results verified the feasibility of the SRD position sensorless control strategy based on the inductive zonal compensation strategy and the SRG position sensorless control strategy based on the full chopper conduction. |