New 'D-state-observer'-based vector control for sensorless drive of permanent-magnet synchronous motors

This paper proposes a new sensorless vector control method that can be applied to both salient-pole and nonsalient-pole permanent-magnet synchronous motors (PMSMs). The proposed method estimates phase of rotor flux by a newly developed flux-state observer for sensorless vector control of PMSMs, which is referred to as the 'D-state observer.' The D-state observer has the following attractive features: 1) it requires no additional steady-state condition for the motor mathematical model; 2) its order is the minimum second; 3) a single observer gain is simply constant over a wide operating range, and easily designed; 4) it utilizes motor parameters in a very simple manner; and 5) its structure is very simple and can be realized at a very low computational load. Usefulness of the proposed method is examined and confirmed through extensive experiments. Index Terms--D-state observer, flux-state observer, minimum order, phase-locked loop (PLL), sensorless vector control, synchronous motor.