AC DC/AC PWM CONVERTER WITH REDUCED ENERGY-STORAGE IN THE DC LINK/

The paper introduces the family of quasi-direct converters, i.e., forc ed-commutated ac/dc/ac converters including small energy storage devic es in the de Link, In particular, the case of three-phase to three-pha se quasi-direct converter is considered. Since energy storage minimiza tion calls for instantaneous input/output power balance, a proper cont rol strategy is needed. The paper describes a simple and effective con trol technique which also provides high-power factor and small distort ion of the supply currents. After a discussion of the general properti es of quasi-direct converters, design criteria of both power and contr ol sections are given, and experimental results of a 2-kVA prototype a re reported.