Research On Low-Speed Sensorless Control Algorithm And Rotor Stress Analysis For IPMSM

Interior Permanent Magnet Synchronous Motor (IPMSM), with its simple structure, high power density, and easy maintenance, is widely used in high-performance servo drive system. The vector control strategy, which requires real-time current, speed and position feedback, is adopted in AC motor control system in order to achieve fast dynamic response, wide speed range, high positioning accuracy, etc. However, conventional mechanical position sensor to obtain real-time rotor position signal is limited because of its shortcomings such as high cost, low reliability and complexity of installation. This paper focuses on sensorless control method, high-frequency rotating voltage injection method, based on IPMSM control system running at zero speed and low speed.In this paper, through the derived PMSM mathematical model under the high-frequency voltage excitation, high-frequency response current expression is analyzed. The basic principle of detecting the rotor position is introduced according to the structure feature of IPMSM. The characteristics of several filters to get the response negative current containing location information is discussed, as well as the basic principles and features of several observers to estimate the rotor position. Finally, due to d axis inductance saturation of IPMSM, the method making use of high-frequency response current to extract magnetic polarity of initial rotor position is considered.For the proposed method, MATLAB/Simulink simulation model is built with the high-frequency rotating voltage injection method based on IPMSM sensorless control system, and the software design and implementation methods of filters and observer are also focused as well as the simulation results.Finally, programs about sensorless control, based on the hardware platform with DSP2812 and 4 pairs of pole IPMSM control system is also written for the experimental verification.At the same time, based on the simulation and experimental results, causes of error between the actuals and estimation of the rotor position is analysed, considering the motor structure and control modules and algorithms. In addition, for the relevant optimization of high-speed IPMSM in high-power servo application, the strength and stress analysis, for the rotor of high-speed interior permanent magnet (IPM) motor, is made in this paper. On this basis, considering the whole complicated process of FEM, another simplified mechanical strength analysis method is presented in this paper. The effectiveness of the proposed method is verified by simulation results.