Novel control scheme for adjustable speed synchronous machine drives

The adjustable speed synchronous machine drive has been established as a high quality drive. Unity power factor control of the machine is expected to be of higher efficiency for the machine and for the inverter. The only existing method is for feedback control of the phase angle between input voltage and current to be zero. The control procedure is complex. This paper reports a newly developed forward control scheme for unity power factor control of the synchronous machine. Simulation shows good performance of the scheme.