Research On Flux Observation Method Of High Speed Permanent Magnet Synchronous Motor With Low Modulation Ratio

The role of High Speed Permanent Magnet Synchronous Motor in military and civilian applications is becoming increasingly prominent.It is valued for its ability to directly drive high speed loads.However,mechanical sensors reduce their dynamic performance.In this paper,the surface-mounted high-speed permanent magnet synchronous motor is taken as the research object.Firstly,the research background of this topic is introduced,which leads to the necessity of carrying out the research work.Secondly,the mathematical model of high-speed permanent magnet synchronous motor is established.According to the mathematical model,the vector control method is further introduced,and several kinds of vector controls,which are widely used at present,are introduced,and their working principles,advantages and disadvantages are analyzed,which lays a solid foundation for the subsequent research.Then,through the mathematical model and the control structure diagram,the PI control without decoupling is analyzed.Due to the existence of the speed term,it is difficult to achieve true independent control of the dq axis current when the speed is increased,especially at high speed;The PI control with feedback decoupling and the PI control with feedforward decoupling are introduced.The improved PI control is proposed by deriving,solving and designing,the zero pole of the closed-loop transfer function can move together when the motor speed changes.Real-time cancellation,good decoupling control,and not affected by motor parameters.The PI control with feedback decoupling and the PI control with feedforward decoupling are introduced.The improved PI control is proposed.By deriving,solving and designing,the zero point and the pole of the closed-loop transfer function can move together when the motor speed changes.Decoupling control is well implemented and is not affected by motor parameters.Then,starting from the traditional flux linkage observation model,the problems of zero drift and parameter influence of the basic model are analyzed.On this basis,by improving the Qualcomm link,although the DC offset can be suppressed,a new problem is introduced,and the phase deviation and amplitude attenuation of the observation result.Using the model reference adaptive method,the adaptive adjustment of the flux linkage comparison result is selected,and the feedback compensation is improved,and the observation effect is achieved very well.At the same time,the position and velocity information can beobtained,and the structure is simple and easy to implement.Finally,simulation verification is performed under MATLAB/Simulink.In the case of high speed,the motor can run stably,and it can quickly adjust and restore stability when sudden load is released.The experimental platform was set up,and the traditional control method and the improved control method were compared.The results show that the improved control method can accurately track the rotor position and the motor runs stably.