Application of a constant-output-power converter in multiple-module converter systems

The origins of the current-sharing problem of parallel-converter systems and the dual problem of voltage sharing in series-converter systems are explored. Both problems are studied by examining the output plane (output current versus output voltage) of a particular converter. It is shown that strict current source behavior is unnecessary for good current sharing in parallel-converter systems, and that converters which behave neither as current nor as voltage sources can share a load equally in an a×b array of converters. One class of converters useful in such systems is that characterized by constant output power (e.g., the clamped series resonant converter). Furthermore, it is shown that constant output power converters are a subset of a broad class of converters whose output voltage is load-dependent, all of which exhibit particular load-sharing good voltage- and current-sharing characteristics. The characteristics of discontinuous mode PWM converters as well as conventional and clamped series resonant converters are examined in detail. A small-signal model of the modular converter system is developed. Experimental results are given