The Research And Design Of PMSM Sensorless Control System

As permanent magnet synchronous motor (PMSM) has advantages such as compact shape, simple structure and high efficiency, the AC control systems based on PMSM have been applied more and more widely in fields such as electric vehicle, industrial control. The traditional control systems adopt mechanical sensor to obtain the speed, which has negative effects. Because the sensorless control technology can improve system reliability and reduce system cost, it can replace the mechanical speed sensor in the traditional control systems, which becomes a research focus in recent years. Based on the relevant documented literature, the profound study has been made for the purpose of developing the sensorless vector control of PMSM.The mathematical model of the PMSM is firstly analysed, and field oriented control scheme of PMSM is established. Based on the above, the structure and working principle of the sliding mode observer are analysed, an improved scheme is investigated to suppress the chattering of the conventional sliding mode observer and the simulation model of sensorless control system based on sliding mode observer is developed. Secondly, the working principle of adaptive observer is introduced and the adaptive observer speed identification scheme applied to the PMSM is designed.The reasonable feedback gain matrix is also developed through the simulation analysis, which improves the dynamic and steady-state performance of the system.The simulation model of sensorless control system based on adaptive observer is also constructed.Then, based on the analysis of the PMSM drive system with small DC-link capacitor, the thesis presents the current control strategy of the system, and researches the sensorless control scheme applied to the system. And the PMSM sensorless control system with small DC-link capacitor which is suitable for the air conditioning compressor is designed.Finally, the PMSM sensorless control experiment platform is established with the digital signal processor TMS320F28335, and a lot of experiments are carried out to verify the slide mode observer and adaptive observer algorithm. The effectiveness of the proposed strategy and algorithm are verified.