| At present,most of the low speed and high torque transmission devices in our country are driven by the combination of conventional speed motor and reduction gear box.However,the reduction gear mechanism will lead to the huge volume of the drive system,increase the maintenance cost,reduce the working reliability and operating efficiency,and the redundant gear mechanism will also bring technical problems such as manufacturing,transportation and assembly to the enterprise,and will also cause lubrication.Oil leakage,noise and pollution problems.Therefore,the direct drive transmission method that eliminates the reduction gear mechanism is adopted.This new transmission device is considered to be a necessary choice for the future development of high-end mechanical equipment,and to improve the transmission system and overall performance.The commonly used direct-drive low-speed high-torque permanent magnet synchronous motor has a large internal space.This paper proposes to study a new type of composite rotor dual-stator low-speed direct-drive synchronous motor,whose rotor adopts external surface mount permanent magnet,internal reluctance,and a magnetic isolation ring in the middle.A composite structure that separates the inside and outside.This structure can improve the utilization of the internal space of the motor.Aiming at this new type of dual-stator synchronous motor with permanent magnet/reluctance rotor,this thesis studies its vector control system and its speed controller.The main content of the thesis is as follows:First,the structure of the new motor and vector control methods at home and abroad are deeply studied,and the mathematical model of this motor is deduced.Aiming at the special structure of the compound rotor and dual-stator of this kind of motor,the torque ratio control system is designed,and the torque ratio control system of the permanent magnet/reluctance rotor dual-stator synchronous motor is built using MATLAB simulation software and Simulink toolbox.Simulation Verify its correctness and feasibility.Secondly,in view of the large speed overshoot problem of the above-mentioned control system when the motor starts and the load changes suddenly,a new type of single speed loop sliding mode speed controller is used to replace the traditional double PI speed loop,and a single speed loop sliding mode speed controller is used.Calculate the reference current of the internal and external motors.The sliding mode speed controller has strong anti-load disturbance ability,which can effectively improve the problem of excessive speed overshoot caused by integral saturation in the traditional PI.A single sliding mode speed loop vector control system for this kind of motor is built on the MATLAB/Simulink platform,The correctness and feasibility of the theory are verified by simulation.Finally,in view of the inaccurate calculation of the reference current of the internal and external motors and the saturation of the integral link caused by the single-speed sliding-mode speed controller,an improved reduced-order Romberg observer was designed,and the output of the improved Romberg observer was designed.As the negative feedback of the sliding mode speed controller,the disturbance torque can improve the calculation accuracy of the reference current,weaken the speed overshoot,further improve the response speed of the motor starting and load sudden changes,and shorten the response time when the stability is reached.A permanent magnet/reluctance rotor dual-stator synchronous motor vector control system based on a compound sliding mode speed controller was built by MATLAB/Simulink,and compared with a vector control system based on a traditional sliding mode speed controller. |
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