TECHNIQUES FOR ASIC IMPLEMENTATION OF VECTOR CONTROL

Harmonic-free vector control, in which both the phase and amplitude of a three-phase current are controlled digitally to within close limits , is a common requirement in many power conversion applications. These include the control of three-phase motors, and the conversion of elec trical power from three-phase AC to DC, or the inverse, with low suppl y harmonic content. Vector control at a specified frequency relies upo n the generation of accurate sine and cosine waves, computation of the in-phase and quadrature components of the input current, and then rec onversion to the three-phase sinusoidally varying drive values. The au thors discuss the options available for implementation of the referenc e sine generator as an ASIC cell, and show how an application specific processor can be designed to achieve the very high performance combin ed with small area necessary to deal with the current transformation. Both functions are integrated in a design using less than 25 000 gate equivalents at 16-bit accuracy.