An effective sensorless backstepping control of PMSM in high-altitude electric propulsion system

According to study on sensorless control of PMSM used in high-altitude electric propulsion system, a sensorless backstepping control method of PMSM based on sliding mode phase-locked loop speed observer is proposed in this paper. The EMF equations are established by sliding mode equations based on PMSM stator mathematical models, and the speed and rotor position are evaluated by phase-locked loop. The backstepping algorithm is applied to design speed and current tracking controller. The stability of observer is proved by Lyapunov stability theory. The hardware in loop experiment of PMSM sensorless backstepping control system is implemented based on dSPACE experiment platform. Simulink simulation and experiment results show that the sensorless backstepping control of PMSM based on sliding mode phase-locked loop speed observer is correct and feasible. The speed and rotor position of PMSM with small torque load in low speed can be evaluated accurately based on sliding mode phase-locked loop speed observer, the rotor phase errors produced by the first order low-pass filters can be dynamically compensated for by the variable cutoff frequency method according to reference speed, and on the basis of guaranteeing the whole control system's asymptotical stability, backstepping controller can achieve the speed and current regulation effectively.