Integrated optimum control of quasi-direct converters

This paper deals with control and design of quasi-direct converters, i.e. AC/AC converters including a forced-commutated rectifier, an inverter, and a small filter in the DC link. Converter performance can be optimized by means of a predictive digital control strategy, which ensures instantaneous input-output power balance, fast response, and high power factor. After a discussion of the control strategy, the paper gives design criteria of both power and control sections. Experimental results of a 2.5-kVA prototype are reported.