Research On Online Parameters Accurate Estimation Method Of Permanent Magnet Synchronous Motor For New Energy Vehicles

Permanent magnet synchronous motors(PMSM)are the first choice for new energy vehicles because of their high power density,high efficiency,and small torque ripple.In order to improve the torque output capability and speed range of PMSMs,the maximum torque current ratio control(MTPA)and flux weakening control(FW)are widely used.However,the d-q axis inductances and the permanent magnet flux linkage will be affected by the working conditions.The control algorithms based on the constant parameters are difficult to meet the demand,and the actual current trajectory will deviate from the ideal one.Therefore,it is necessary to estimate the parameters online to improve the control accuracy.On the other hand,the resolvers as rotor position sensor are widely used in the PMSM control system of new energy vehicles,and their reliability is crucial for vehicle stability and safety.There are hidden dangers of the resolvers such as amplitude imbalance and incomplete quadrature,disconnection and jamming,so it is necessary to adopt fault-tolerant control(FTC)for the resolvers.Online estimation of rotor position using sensorless control algorithm is an effective way to achieve fault-tolerant control.To solve the above problems,this dissertation conducted the following researches:In order to improve the torque output capability and speed range of PMSM,firstly,the MTPA control algorithm is designed based on the analytical formula method and the FW control algorithm is designed based on the gradient descent method.Aiming at the d-q axis inductances and permanent magnet flux linkage which are more sensitive in MTPA and FW algorithm,a novel online parameters estimation technology is proposed to accurately estimate them online.Then,the MTPA and the FW control algorithms are optimized using the parameters estimation results.Finally,the effectiveness of the proposed algorithm is verified by simulation.In order to realize the FTC of the PMSM resolvers,the rotor position is estimated by the sensorless algorithm based on high-frequency signal injection method(HFSI)and a back electromotive observer.Secondly,a FTC is designed based on this sensorless algorithm.Finally,the effectiveness of the proposed FTC is verified by simulation and experiment.