Design of the demodulation method of position and rotate speed signals for PMSM servo system

Applying spin transformer to achieve the principle of magnetic pole position and speed measure and a new method are presented in this paper. The actual magnetic pole position signal and speed signal demodulation circuits are given out, and the demodulation principle is analyzed exhaustively. The scheme is reliable and its high measure precision can completely meet the need of high performance AC servo system used in NC machine tool.