Experimental Evaluation of Space Vector Oriented Active DC-Side Current Balancing of Two Parallel Connected Three-Phase Three-Switch Buck-Type Unity Power Factor Rectifier Systems

In this paper the parallel connection of two three-phase buck-type unity power factor rectifier systems is investigated experimentally for a 10kW DSP-controlled prototype. There, a space vector modulation scheme is employed which shows all advantages of interleaved operation of the two systems. Three control schemes for active DC-side current balancing are described. The control schemes do differ concerning their control action and concerning additional switching losses. All control structures discussed in this paper are based on employing an additional free-wheeling states which do allow to influence the rate of change of the DC-side currents and can therefore be used for DC-side current balancing.