Parallel active filter system implementation and design issues for utility interface of adjustable speed drive systems

This paper presents a parallel active filter system implementation for utility interface of an an adjustable speed drive air-conditioner chiller application to meet IEEE 519 recommended harmonic standards. Specifications of displacement power factor, efficiency, cost, size and packaging requirements with the rectifier front-end topology are used to determine the optimal active filter solution. Design issues and interaction of parallel active filter inverter switching ripple filter, rectifier front-end and supply are addressed. A synchronous reference frame based controller and a predictive charge error based current regulator and their hardware implementation has been developed for the parallel active filter. Experimental results of the parallel active filter system are presented for a 'stiff' utility system interface of a 450 kW adjustable speed drive air-conditioner chiller application to meet IEEE 519 harmonic limits in the supply current.