Research On State Feedback Control And Position Sensorless Control Of Permanent Magnet Hub Motor

With the increasingly serious problems of environmental pollution and resource shortages,energy conservation and emission reduction have become more and more important.The development of new energy vehicles is a major strategy related to national rejuvenation.The electrification of automobiles is one of the important measures for energy conservation and emission reduction.Hub motor(HM)is a kind of motor which is directly placed in the wheel.Compared with the driving form of the traditional car,the HM car saves the bulky mechanical transmission system,which greatly improves the utilization rate of battery energy,improves the vehicle handling stability and safety.Therefore,the hub motor is also known as the ultimate driving form of electric vehicles.Compared with other types of motors,permanent magnet synchronous motor(PMSM)has the advantages of high-power density,low loss and small size.Thus,permanent magnet synchronous hub motor(PMSHM)is one of the most widely used hub motors.It is of great significance to develop higher performance PMSHM control algorithm.This dissertation was supported by the National Natural Science Foundation of China under Project 51875261,the Natural Science Foundation of Jiangsu Province of China under Projects BK20180046 and BK20170071,the Key Project of Natural Science Foundation of Jiangsu Higher Education Institutions under Project 17KJA460005.The basic principles,mathematical models,control methods,dSPACEbased rapid control prototype platform construction and experimental verification of new-energy vehicle hub motors are studied in this dissertation.The main research contents are as follows:1.The structure and operation principle of PMSHM,analysis the mathematical model of PMSHM and vector transformation in different coordinate systems are explored.The principle of vector control and the implementation of SVPWM are mainly discussed,and simulation research on double closed-loop vector control strategy is conducted,which lays a foundation for subsequent improvement research.2.Due to shortcomings of traditional control methods,a state feedback controller structure based on Gray Wolf algorithm is proposed.The linearization of the hub motor model is implemented by using feedback decoupling.The integral of current and speed error is added to the motor state space model to improve steady state performance.The fitness function used to select the parameters of the state feedback controller in the gray wolf algorithm is determined by the control target,a speed overshoot penalty term is introduced based on the penalty control idea into the fitness function,so that the designed controller can suppress overshoot as much as possible.3.A sensorless vector control of PMSHM based on binary search algorithm PLL(BSA-PLL)is proposed.The fitness function for selecting the rotor position is designed based on the characteristics of the motor back EMF.The position estimation accuracy can be improved by continuous binary iteration of position space.In view of the small amplitude of back EMF in PMSHM at low speed,a startup method at low speed is designed.4.Based on Dspace,a rapid control prototype development platform was built.The hardware design steps were introduced in detail,including drive circuit,protection circuit and sensor circuit.The selection of software interface was introduced,as well.These works lay a basic for further experimental study of the PMSHM.5.On the designed rapid control prototype development platform,the experimental verification of the designed state feedback controller and position sensorless controller was carried out.The experimental results show that the designed state feedback controller can reach the predetermined goal both in steady state and transient state.Compared with the conventional PLL,the proposed BSA-PLL has a faster response speed and smaller oscillation.