Research On Control Of Permanent Magnet Synchronous Motor For Vehicle Air Conditioning Based On Sliding Mode Observer

The development of electric vehicle technology has driven the progress of its auxiliary system.Fuel vehicle air conditioning compressors are driven by engines;while electric vehicles have eliminated engines,and air conditioning systems are driven by independent motors,which can achieve dynamic speed regulation.Compared with other air conditioning systems such as AC asynchronous motors,Permanent Magnet Synchronous Motor(PMSM)has high efficiency,small size,and stable operation,which can better meet the driving performance of on-board air conditioning motors.This paper takes PMSM,the core component of electric vehicle air conditioner,as the research object,considering that the control system needs the feedback of motor rotor position and speed,but the installation of mechanical sensors in the vehicle air conditioner motor increases the size and cost;at the same time,the motor is in the high temperature and corrosive working environment,and the sensor detection accuracy is difficult to guarantee;therefore,the observer method is used to conduct a sensorless PMSM control system for vehicle air conditioner.research.First,the development of electric vehicle air conditioner and the current status of PMSM control technology and algorithm research are described;the principle of electric air conditioner and the structure of PMSM are introduced,and the mathematical model related to PMSM is established.Detailed mathematical theoretical derivation is carried out for vector control and space vector pulse width modulation techniques.Secondly,the influence of the PMSM speed on the performance of the on-board air conditioner under steady state is studied;to improve the speed regulation performance of the air conditioner PMSM,a fuzzy PI speed controller is designed by combining the advantages of fuzzy control and PID control.Using fuzzy control to optimize PI parameters,a simulation model of vector control is established,and Simulink simulation is verified under various operating conditions,which provides a basic model for subsequent implementation of sensorless vector control.Then,in order to replace mechanical sensors as signal feedback,a sliding mode observer is constructed.The sliding mode control theory is applied to the observer design,and the observer design process is derived in the stationary coordinate system.In order to suppress the sliding mode jitter and reduce the observed signal pulsation.Firstly,the sliding mode control function is improved by using boundary layer control method with sinusoidal saturation function to achieve fuzzy adaptive adjustment of the boundary layer thickness;secondly,the normalized phase-locked loop is used instead of the traditional inverse tangent position estimation method to avoid amplifying the high frequency jitter signal.A complete sensorless control vector model is established,and simulation verification analysis is performed to improve the observation performance.Finally,to verify the practical effect of the improved strategy,a DSP28335-based PMSM drive control platform is built,and the main circuit principles,such as drive circuit and sampling circuit,are analyzed.The relevant algorithm program is written on the CCS platform and burned into the DSP for relevant experiments.The test results are consistent with the theoretical analysis and simulation calculation,which show the feasibility of the fuzzy PI controller and the improved sliding mode observer,and can make the system operate stably.