The speed and the power f a c t o r are controlled i n order t o optimize the operation of an adjustable speed s l i p power recovery d r i v e . This i s accemplished b y means o f a variable voltage -variable frequency -variable phase angle power converter. The function o f the d i g i t a l c o n t r o l l e r o f the power converter i s t o provide the on l i n e speed and power f a c t o r regulation. The appropriate b u i l t hardware and the software developed are described. This scheme has an accurate voltage output with v e r y l o w harmonic content, a good r e s o l u t i o n f o r the phase angle regulation and the frequency control with the p o s s i b i l i t y o f range extension.