Sensorless Control of PMSM Using Chua's Circuit Based on Sliding Mode Observer

This paper presented a novel method for the measurement of stator phase current using chaotic synchronization, which was applied to sensorless control of permanent magnet synchronous motor (PMSM). This method is used to solve the problem that rotor position and speed is difficult to obtain in the existing sensorless control technology when PMSM is running at low speed. This is because that the back electromotive force (back-EMF) is very small and the signal to noise ratio is very low. The method is based on Chua's circuit and combines the theory of chaotic synchronization and the adaptive algorithm to construct a weak signal detection system. In this system, two chaotic circuits are used, one as the driving end and the other as the response end. The phase current is put into the driving end, and its the amplitude is approximated by the adaptive controller. This detection system utilizes the characteristics of the chaotic system and completes the parameter estimation by minimizing the synchronization error between two ends, which is easily obtained and avoids the complex solution of the phase space trajectory. According to the detection system and sliding mode observer, a sensorless vector control system was constructed, and its control performance was evaluated by the simulation. The results show that the detection system retains excellent detection performance of the chaotic system, improves the detection efficiency, simplifies the parameter settings and meets the requirements of detection speed and accuracy. Compared with the traditional method, the control system has a better immunity to noise, and can provide more accurate estimation of rotor position and speed.