Research On Efficiency Optimization Control Of The Four-phase Doubly Salient Electromagnetic Machine

Doubly Salient Electro-magnetic Machine(DSEM)has the characteristics of simple structure,adjustable excitation,wide speed range and flexible control so that it performs well in speed-adjusting applications.However,due to the existence of field winding,the efficiency of DSEM is lower than other kinds of Doubly Salient Permanent-magnet Machine(DSPM).An efficiency optimization control strategy is needed in DSEM.It is based on asymmetric current control and reduces the loss of DSEM by coordinating the distribution of excitation and armature current.According to the H-bridge topology,widening conduction interval control mode is put forward and the general formulas of the forward and negative advance angle are gotten.It can improve the torque and efficiency to the certain degree.Firstly,linear model and working principle of the four-phase DSEM are introduced.Asymmetric current control and new H-bridge power circuit are put forword in the analysis process of traditional control methods.Besides,H-bridge power circuit is extended to dual-phase control.To continue,on the basis of asymmetric current control,a coordinated control strategy of excitation and armature current is proposed for a four-phase 8/6-pole low-speed DSEM,which can minimize copper loss.The efficiency optimization control of the four-phase DSEM is realized by analyzing the causes of other loss neglect of the prototype and the proposal of widening the conduction interval.Finally,aiming at the control method adopted,a speed control system based on Labview is built.The hardware and software design of the system are introduced.The efficiency optimization control strategy is validated by experiments.The results show that the strategy can effectively reduce the loss of four-phase doubly salient motor and improve the efficiency of the motor.The experimental platform is used to prove the validity of the widening control of the conduction interval.