Simple Position Sensorless Speed Control Method for Permanent Magnet Synchronous Motors Using Flux Vector Control

This paper proposes a simple position sensorless speed control method for permanent magnet synchronous motors (PMSMs) using flux vector. The proposed method is simpler than direct torque control and does not require speed and torque controller. Speed control can be realized by applying a synchronous drive instead of a speed controller, which is not affected by speed estimation and torque estimation accuracy. In addition, stabilization control is realized by feeding back torque pulsation because only the synchronous drive becomes oscillatory. The stability of the proposed method is analyzed by root locus, and it is shown that the gain design is easy to obtain a desired response. Furthermore, maximum torque-per-ampere control, which is known as the high-efficiency drive method, is realized by applying armature flux reaction control, which is robust against parameter errors of PMSM and voltage errors due to an inverter. Finally, the effectiveness of the proposed method is confirmed by analysis and experiments.