An Improved 3-Step Startup Method Based on Sensorless Vector Control of PMSM

Permanent Magnet Synchronous Motor (PMSM) has been widely used because of its high efficiency, easy maintenance, and low cost, etc. Although plenty of sensorless control methods regarding low speed have been applied to the motor control, yet these methods are mostly complex and a little unreliable. To solve the problem, for the industrial PMSM without the requirement of running the motor for a long time at low speed, this paper proposes an improved 3-step startup method. The robustness, stability and response rapidness of the proposed method are discussed in detail, particularly for the transition process switched to the speed feedback control with sliding mode observer (SMO). In order to achieve a smooth transition, parabolic declining function and initial integral value selection are introduced. Simulation and experimental results on a 2.7-HP PMSM drive confirm the correctness of the proposed startup method.