Research On Direct Torque Control Of Five-phase IPM Motor Based On Sensorless Control

The advantages of EVs such as less pollution and high effciency help realize sustainable development of economy and society.Permanent magnet synchronous motor(PMSM),featuring high power density and wide speed-regulating scope,is widely applied in electric vehicles driving system.Among all PMSMs,five-phase interior permanent magnet(IPM)synchronous motor have little ripple in electromagnetic torque due to flexible control strategies caused by multidimensional system.To weigh the motor's dynamic performance,quick rotot response is an indispensable index,direct torque control(DTC)is characteristic of quick torque response and robustness.However,there is severe ripple of torque in traditional DTC method.Therefore,an improved DTC strategy is promoted in this paper.The rotor position and velocity usually detected by sensors is essential in the control system,however,extra sensors tend to result in lower reliability of the driving system.Based on sensorless control,research on driving system of five-phase IPM motor is also perfomed in this paper.First of all,the background and significance of the research subject are introduced.Additionally,both domestic and overseas research status of multiphase motor,control methods,direct torque control of multiphase motor,and sensorless control are described.Secondly,the operating theory of five-phase fault-tolerant IPM motor is analyzed and mathematical model of five-phase IPM motor is established.SVM-DTC algorithm is illuminated and adopted to reduce torque ripple.Based on Matlab/Simulink,model of five-phase fault-tolerant IPM motor is set up and simulation results are analyzed.Then,sensorless control method is introduced theoretically.High-frequency sinusoidal voltage injection algorithm is applied in motor's low speed operation and sliding mode observer(SMO)is used in high speed operation to estimate rotor position and velocity.To solve the problem of conventional SMO,sigmoid function is used instead of switch function.To eliminate the phase delay caused by traditional low-pass filter,the back-EMF observer is applied in obtaining the back-EMF information.Weighted and switching algorithm is used to realize combination of the two sensorless methods.Based on sensorless control,simulation model of five-phase fault-tolerant IPM motor is built and simulation results are analyzed.Finally,the hardware and software experimental platform based on dSPACE are devoloped to research the effectiveness of the control strategies promoted in this paper,which will lay the foundation to further study and practical application.