A wide-speed-range sensorless control for an IPMSM is deeply studied in this paper, which combines the high-frequency injection (HFI) method and sliding-mode observer (SMO) method. At low-speed range, a rotating voltage signal injected into IPMSM; rotor position can be estimated by HFI based on saliency of IPMSM. high-speed SMO extended back electromotive force (EMF) utilized to estimate positi...