Research On Control System Of Hybrid Excitation Synchronous Motor

Hybrid excitation synchronous motor not only has the advantages of high power density of permanent magnet synchronous motor,but also has the advantages of easy regulation and wide speed range.It has wide application prospects in production and life.With the progress of technology,It takes higher requirements for the stability and dynamic characteristics of motor control system.Therefore,further studying the control system of hybrid excitation synchronous motor and improving its control performance are of positive significance to widen the application scope of hybrid excitation synchronous motor.In this paper,The basic structure of hybrid excitation synchronous motor was described,the mathematical model of the motor was built in two-phase rotating coordinate system,then,the inductance of the DC axis was calculated under different saturation states by frozen permeability method,and the influence of inductance parameters on the electromagnetic torque was analysed when the saturation of the magnetic circuit was considered,which laid the foundation for the follow-up study of the control system.A zoning control strategy based on vector control system was proposed.The operation area of hybrid excitation synchronous motor was divided into low-speed zone,medium-speed zone and high-speed zone.The maximum torque-current ratio control strategy was adopted in the middle-low speed zone,and the control strategy with power factor equals to 1 was adopted in the high-speed zone.Different control modes were selected according to the actual speed of the motor.The simulation model based on the control strategy was built by using simulation software.The low-speed dynamic performance of the motor at 1500r/min and the medium-high-speed dynamic performance at 3300 r/min and 7000 r/min was simulated and analyzed,thus,the correctness of the control strategy was verified.Based on the different inductance parameters of direct and quadrature axes under different saturation conditions,a direct torque control strategy for hybrid excitation synchronous motor(HESM)was proposed,Then,the simulation model of the direct torque control system of hybrid excitation synchronous motor was established by using the simulation software.And the dynamic performance of the motor under sudden load and sudden load reduction was simulated andanalyzed,thus,the correctness of the control strategy was verified.In order to improve the robustness and rapidity of the control system,a second-order fast terminal sliding mode torque controller was designed based on the hybrid excitation synchronous motor direct torque control system.Compared with the direct torque control system and vector control system using the controller named PI,the effectiveness of the second-order fast terminal sliding mode torque controller was verified.