Frequency hybrid vector control with MIR strategy for sensorless synchronous motor drive

This paper proposes a newly developed frequency-hybrid (FH) vector control scheme with monotonously-increasing-region (MIR) strategy for sensorless cylindrical synchronous motor drive. It is confirmed through tests using a 750 (W) motor that the proposed sensorless scheme has the following high potential: 1) it operates in both torque and speed controls; 2) it operates in both motoring and regenerating modes; 3) torque producing characteristics has good linearity over the rated torque range under constant speed; 4) for steady speed performance with correct flux orientation, its speed ratio based on rated speed is about 1/300 under motoring rated load and 1/200 under regenerating rated load; 5) for transient speed performance, its servo-tracking ability allows tracking of speed command of acceleration ±5000 (rad/s²) under no-load