Research On Sensorless Control Of Permanent Magnetic Synchronous Motor

As the core part in various kinds of ac speed regulating occasions, permanent magnet synchronous motor(PMSM) is superior at dynamic response, productivity and power density, and it is receiving public concern increasingly. So researching on the control and drive system of PMSM has a high application value. Commonly used motor control methods are vector control and direct torque control, both of two methods require real- time detecting of rotor position information. In some special occasion, such as air conditioner compressor and refrigerator compressor, the high temperature and high pressure will decrease reliability of mechanical sensor. In addition, many civilian industries is sensitive to the cost, which also limits the use of mechanical sensor. Therefore, the sensorless control of permanent magnet synchronous motor has been the scholars’ research hotspot all the time. There are three key points, estimating the rotor position, calculating the rotor speed and feeding back the rotor information. The new sliding mode observer, as an application of sliding mode variable structure control used in sensorless control, has the advantage of strong robustness and high observation accuracy. It can suppress chattering and improve sensorless control accuracy. This paper will mainly probe into calculating the rotor speed and feeding back the rotor information in the sensorless control of permanent magnet synchronous motor system.Firstly, this paper built the new sliding mode observer mathematical model of permanent magnet synchronous motor according to the analysis of mathematical model of PMSM and vector control theory.Secondly, several motor speed estimation algorithms were analyzed, their advantages and disadvantages of these algorithms were also compared. And these algorithms were optimized. Their performance of estimating speed was improved, too. These were also analyzed and verified through MATLAB.Thirdly, according to the different estimation mechanism of PMSM rotor position detection between low speed and high speed. A sensorless open/closed loop control algorithm based on position self-adjustment voltage vector switch was designed. The Simulink model of sensorless open/closed loop control of PMSM system was built. Its performance was verified through MATLAB.Finally, the experimental platform of PMSM drive and control system was established, and the hardware system based on TMS320F28335 DSP and the software were designed to verify the effectiveness of these new control algorithms.