The Study On The Sensorless Vector Control System Of Permanent Magnet Synchronous Motors

Electric Vehicle (EV) has developed rapidly vehicle in the recent years as the problem of energy and environment is becoming increasingly serious. However, many prolems are demanded to be solved in order to develop this kind of vehicle, and high performance motor driving system is one of the key techonlogies. The main goal of this thesis is to research the sensorless control techonlogy of PMSM in EV.Based on the comparisons of existent sensorless control methods, and by taking into account the special demands of EV on the speed-control sensorless system, we design a sensorless vector control system with high frequency (HF) injection. This thesis first introduces the details of HF theory, and shows the advantage of HF injection in low speed region. Then, we design every part of sensorless control system. To extract the high frequency current we put forward a new method and achieve good result. The Phase Locked Loop (PLL) is adopted as the algorithm of getting rotor position. The study towards theory, mathematical models, stability, as well as anti-jamming performance of PLL is conducted in-depth. Later, we design the parameters for PLL. Since the HF injection is unble to identify the pole of rotor, we propose a solution using the motor saturation effect in theory. Finally, the factors that impact the high-frequency estimation error are analyzed.Based on the theory, we build the model of the algorithm with the help of Simulink. The speed and position characteristic are analyzed under the situation of start, loading and changing speed reference, respectively. Finally we validate the theory by the MSK2407 control board which is made by TECHNOSOFT.