Research On Adaptive Control Strategy For Winding Switchable Motor

The winding switchable permanent magnet synchronous motor(PMSM)can be widely used in the field of electric vehicle(EV)drive because it can realize the advantages of high torque output,wide speed range and wide efficiency zone operation.At the same time,the winding switchable motor has its own special problems.It is necessary to consider the adverse effects on the vehicle operation caused by the change of motor parameters before and after switching,and to consider the suitable winding switching strategy to solve the problems of torque and speed fluctuation when switching.Therefore,this paper will study the control strategy of winding switchable PMSM under multiple operating conditions,so that the vehicle applying winding switchable PMSM has good operating performance in the full speed range.The main contents of this paper are as follows:Firstly,a mathematical model is established with the structural characteristics of winding switchable PMSM,and the relationship between voltage,current and parameter changes before and after winding switching is analyzed.For the characteristics of parameter changes before and after winding switching,a parameter design method based on PI controller is proposed to meet the performance requirements of the motor under different winding states.To improve the anti-parameter disturbance capability of the system,a composite controller based on sliding-mode variable structure is designed,and good control performance is achieved when the motor parameters change by designing a sliding-mode-based extended disturbance observer and a sliding-mode-based speed controller.Simulation experiments show that the proposed strategy can effectively cope with the adverse effects caused by the motor parameter changes.Secondly,to address the problem of voltage and current shocks generated during winding switching of winding-switching type motors,the switching process of different switching methods of the bottom winding is modeled and analyzed,and a method of switching based on phase current state is proposed to reduce voltage and current shocks.To address the problem of torque and speed fluctuations during winding switching,the root causes of torque and speed fluctuations are analyzed,and an anti-disturbance observation suppression strategy based on feedforward compensation is proposed to effectively reduce torque and speed fluctuations.Based on the root cause of fluctuations,a fluctuation suppression strategy based on winding state switching is designed,and the correctness of the strategy is verified by simulation.Then,in order to realize the automatic switching of the motor running state,the principle of selecting the optimal switching domain of the winding switching motor is analyzed.Firstly,the operating area of the winding switching motor is roughly divided to determine the respective operating range of the winding in series and parallel state,and then the optimal switching domain of the winding switching motor is obtained with the goal of optimal efficiency.The winding switching logic based on the optimal switching domain is designed to automatically switch the motor during operation based on the speed judgment,and finally the effectiveness of the switching logic is verified by simulation.Finally,an experimental platform for winding switchable motors is built,and the motor control performance of PI controller-based and sliding-mode-based composite controllers is verified respectively.Then,the proposed speed fluctuation suppression strategy and winding switching judgment logic are experimentally verified to prove the effectiveness of the proposed strategy.