Research On Sensorless Technology Of Permanent Magnet Synchronous Motor At Low Speed

The core of the electric tool is its drive motor,it directly determines the performance of the electric tool.The traditional drive motor has many problems such as torque ripple and noise,which limits the further development of electric tools.Therefore,the permanent magnet synchronous motor(PMSM)with better performance is considered for motor drive.Using permanent magnet synchronous motor as drive motor will face two major problems: one is the implementation of the low speed sensorless technology,for the limits of the electric tool working environment,cost and Overload condition at low speed,it is necessary to optimize the traditional low speed sensorless technology;the two is to improve the performance of the speed regulating system.In this context,this paper mainly studies two aspects of permanent magnet synchronous motor(PMSM)sensorless control system at low speed and the speed loop controller optimization of permanent magnet synchronous motor.The whole research is as followings:First,the background and current situation of the research are introduced,the model of permanent magnet synchronous motor system and the principle of vector control are expounded.Secondly,based on traditional pulse high frequency voltage injection method,optimizing and improving the signal extraction scheme by using parallel EPLL phase compensation scheme.The algorithm can extract the position signal quickly and accurately,and effectively reduce the angle error of the system.At the same time,the nonlinearity of the inverter is compensated,and the dynamic performance of the system is improved.Finally,the theoretical analysis is verified by simulation.Thirdly,through establishing the transfer function of traditional PI/IP controller,analyzes its dynamic performance,based on this,the composite structure of the fractional speed loop controller is studied.Further studing the control performance of the controller,and designing theoretical values for system performance,the traceability and robustness of the controller are verified by simulation.Finally,the experiment platform based on MC56F82743 is built.the hardware design and the software design process are expounded,and the theoretical research is verified by experiments.