Based on a (d,q) synchronous frame, the control problems of synchronous reluctance motors are outlined. In particular, the effect of magnetic saturation, core loss, and angular measurement errors of various types are evidenced. A flux-observer-based control scheme, capable of overcoming most of the above problems, is proposed. The proposed control has been implemented on a prototype drive, adopting a 17-N/spl middot/m 8000-r/min motor. The experimental results show quite a good performance, with particular emphasis on those applications which require a large constant-power speed range.