Research On Sensorless Control For Permanent Magnet Synchronous Motor Control Based On The Improved Sliding Mode Observer

At present,the permanent magnet synchronous motor is widely used.In general,the transmission system of the motor needs to install the mechanical sensor on the rotor shaft in order to measure the speed and position of the rotor.These mechanical sensors are usually encoders,solvers and tachometer generators.The mechanical sensor provides the rotor signal required by the motor,but also brings a series of problems to the transmission system.First,the mechanical sensor increases the rotational inertia on the motor shaft and the space size and volume of the motor.Secondly,the transmission system can not be widely adapted to various occasions by the conditions of the use of the mechanical sensor such as temperature,humidity and vibration.Finally,the cost of the mechanical sensor is high and the cost of the engineering is increased.Among many sensorless technologies,sliding mode observer is insensitive to parameter changes and external disturbances,especially suitable for permanent magnet synchronous motor control.But sliding mode control also has its own problems,the more prominent is the high frequency chattering and the phase lag of the rotation angle.Therefore,we need to improve the speed of sliding mode algorithm and the accuracy of rotation estimation.Firstly,according to the theory of sliding mode control and the basic principle of permanent magnet synchronous motor,a model of permanent magnet synchronous motor system based on the sliding mode sensorless controller is established.Emphasis is laid on the research and improvement of the estimated speed,speed error,angle phase delay and other technical points.Continuous function is used to replace the traditional switching function and the low-pass filter respectively.The controller is improved tovariable cut-off frequency low-pass filter,angle compensation to variable angle compensation,and Kalman filter is used for secondary filtering.In addition,the sliding mode control is attempted to replace the original PI controller in the speed loop.Based on the optimization of the first-order sliding mode algorithm,the Super-Twisting second-order sliding mode theory is applied to the current link of the system and related optimization is made.The actual performance of the motor under uniform speed,variable speed and load is verified by simulation.Finally,the motor test platform is designed,the similar parts of other people's technical solutions are cited to verify the feasibility of MATLAB simulation and the instructive meanings for engineering practice.