Frequency-Hybrid Vector Control with Monotonously-Increasing-Region Strategy for Sensorless Synchronous Motor Drive

Abstract

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 to track speed command of acceleration±5, 000 (rad/s²) under no-load.