Research On Windings Switching Control Strategies Of Permanent Magnet Synchronous Motor With Dual Windings

Because of the advantages of large torque at low speed and wide speed range,the permanent magnet synchronous motor with dual windings can effectively reduce the size of the space and increase the response speed of shifting,instead of the mechanical gearshift scheme with motor and gearbox in traditional special vehicles.However,when the motor is carried out switching its windings,the process of switching and the change of parameters are bound to have an adverse impact on the dynamic characteristics of the system,which may lead to fluctuations of speed and torque,and current spikes.Therefore,in order to realize automatic and smooth windings switching and ensure the stability of vehicles,this paper focuses on the control strategy and windings switching strategy of the permanent magnet synchronous motor with dual windings.The main contents are as follows:Firstly,according to the structure characteristics of the PMSM with dual windings,the mathematical model of the motor is built,and the vector control strategy of the motor in the non-switching state is formulated by analyzing its operational characteristics.Aiming at the changes of the state of working in series and parallel and the parameters in the switching process,a regulator based on the multi parameter sets optimization control is designed.The feasibility and effectiveness of the applied control strategy are verified by simulation.Secondly,for the windings switching circuit of the PMSM with dual windings with a single inverter,the paper compares and analyzes the two topologies with 8 switches and 9 switches from the aspects of working principle and windings copper consumption.The equivalent circuits of stator windings of the two topologies are shown.The circulating current of the windings is solved by the node voltage method,and the principle of selecting the topology of the windings switching circuit is given based on the calculation of circulating current and the results of performance comparison.The advantages and disadvantages of mechanical switches and electrical switches are compared and analyzed.The evaluation standard for selecting switches and the design schemes of different switches triggering are given.Thirdly,through theoretical analysis and simulation research,advantages and disadvantages of different windings switching modes are compared,and windings switching modes suitable for different switching switches are analyzed.The optimal switching mode,three-phase synchronous step-by-step switching,is proposed to realize smooth switching of windings.Under the condition of applying three-phase synchronous step-by-step switching,combined with the specific parameters and application background of the prototype,the reasonable switching domain is divided into several subdomains,on which simulation studies are carried out.The method of determining the optimal switching domain is established,which can be used as the basis for formulating the windings switching criterion and corresponding control strategies,so as to realize automatic switching of the windings.Finally,the experimental platform of the PMSM with dual windings is built.The performance of the motor under different conditions,including windings in series,windings in parallel and windings switching,is studied experimentally.The vector control strategy based on the multi parameter sets optimization control and the windings switching control proposed in this paper are evaluated experimentally.