Encoderless servo drive with adequately designed IPMSM for saliency-based position detection

This paper presents a newly developed encoderless servo drive with an adequately designed interior permanent magnet synchronous motor (IPMSM). The motor for encoderless servo drive is designed to act like resolver incorporated with saliency-based position detection technique. The resolution of the position detection and sustainability against load are considered in the design. As the position detection a pulse voltage injection technique is employed to realize higher dynamics in the control performance than conventional technique. This paper mainly focuses on the technology fusion in between motor design and control design. Finally, the fast initial pole positioning, the high-dynamics performance in position and speed control, which are sufficient for servo drive applications, are shown in this paper. The net-resolution of the position detection is about 10 bits, and the accuracy of positioning is less than 1 mechanical degree in position control at steady state.