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 performances can be optimised 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.