Sensorless Vector Control Of Permanent Magnet Synchronous Motor For Refrigerator Compressor

In recent years,in the field of refrigerator compressor,compared with asynchronous motor,the efficiency ratio of permanent magnet synchronous motor(PMSM)under the same capacity is increased by about 2%-8%.At the same time,the application of permanent magnet synchronous motor(PMSM)has been developed rapidly due to the improvement of permanent magnet material performance and the decrease of price.Therefore,permanent magnet synchronous motor(PMSM)has become a new favorite in refrigerator compressor field.For the rotor position detection of permanent magnet synchronous motor(PMSM),because of the limitation of high temperature and high pressure environment in refrigerator compressor,the position precision observed by traditional position sensor technology is often greatly affected.Therefore,in order to overcome the above shortcomings,a non-position observation method based on anti-electromotive force is proposed in this paper.This method mainly uses sliding mode observer and phase-locked loop technology to estimate the rotor position and speed in real-time and improve the low-frequency start-up performance of refrigerator compressor effectively.The key of this paper lies in the design of sliding mode observer,which aims to realize the effectiveness and stability of the sensorless vector control system of refrigerator compressor.For this reason,this paper starts from three parts: theoretical derivation,simulation verification and experimental verification.In terms of theoretical derivation,by using the current state equation of permanent magnet synchronous motor and the current state equation of sliding mode observer in static two-phase coordinate system,the state error equation is obtained,and the phase locked loop module is used.The rotor position and speed are derived.For simulation verification,the sliding mode observer module is constructed according to the theoretical derivation,and combined with the phase-locked loop module,coordinate transformation module,space vector pulse width modulation module and so on.The simulation model of position sensorless vector control system for permanent magnet synchronous motor(PMSM)is built,and the simulation experiment is carried out.For experimental verification,a system experimental platform is built based on PAC5223 control board and sliding mode observer algorithm,and a series of related experiments are carried out.The simulation and experimental results show that the permanent magnet synchronous motor(PMSM)vector control system of the refrigerator compressor designed in this paper has good low-frequency startup performance,accurate rotor position and speed estimation,steady frequency and frequency conversion operation.The refrigeration effect is good,which verifies the feasibility,validity and stability of the control system,and has certain engineering practical significance.