Direct Torque Control And Vector Control Of Synchronous Reluctance Motor

Synchronous reluctance motor(SynRM)has very simple structure and good application prospects,e.s.,high temperature resistance allows it to operate in complex envirornments.Meanwhile,it has good advantages in processing difficulty and material cost,as well as in power density and efficiency.At present,the SynRM is a competetive candidate to replace the traditional asynchronous motor in fan,pump and other fields which need low cost and high performance.It is also tried by some scholars in the field of electric vehicles.In order to study the performance of the SynRM,a mathematical model of the SynRM is established in static and rotating coordinates,respectively.The characteristics of magnetic circuit saturation and its influence on inductance parameters of the SynRM are analyzed.To improve the control performance of the SynRM,the maximum torque per ampere(MTPA)control strategy and voltage space vector modulation(SVM)method are applied to the traditional direct torque control(DTC)method,and a DTC-SVM control method is proposed,based on the MTPA strategy of the SynRM.This method maintains the advantages of simple structure and fast torque response of DTC.In addition,the application of the MTPA strategy in DTC is studied,which minimizes the winding ohmic loss,improves the efficiency and reduce the temperature rise of the motor.Meanwhile,in order to study the high-performance control strategy of SynRM,a simulation model of the SynRM considering the saturation effect is built,and the field-oriented control(FOC)and DTC-SVM control based on the MTPA strategy are investigated.The perf-ormance of these two methods are analyzed and compared with simulation.Also,the necessity of considering the influence of magnetic circuit saturation on the motor parameters in the control is discussed.Furthermore,a SynRM test rig is built.The two control methods are implement to carry out no-load and load experiments.Simulation and experimental results show that both control methods have good control performance for the SynRM.The static performance of the FOC method is slightly better than that of the DTC-SVM method,while the dynamic performance of the DTC-SVM method is better than that of the FOC method.The winding ohimic loss of the motor can be reduced by applying the MTPA strategy which considers the influence of the magnetic circuit saturation on the parameters of the motor.