Application specific integrated circuits for the transformation from three phase AC to DQZ coordinates

The design, fabrication, and testing of two special-purpose digital integrated circuits built for power system applications are described. The two-chip combination performs a transformation from ABC phase coordinates to the direct, quadrature, and zero-sequence coordinates and can thus be used in sequence relays, AC machine control systems, and other modern controls for static compensators and DC systems. The discussion covers the formulation of the algorithms to be implemented, tradeoff in chip space and computing time, the design philosophy of the chip itself, the testing of the chip, and a demonstration of the use of these ICs in a negative-sequence-voltage measuring circuit