Digital load share controller design of paralleled phase-shifted full-bridge converters referencing the highest current

Abstract

For a high power demand and N+1 redundancy system, this paper presents a digital load share (LS) controller design and its implementation for paralleled phase-shifted full-bridge converters (PSFBC) used in distributed power systems. By adopting the digital control strategy, separately used ICs for both PSFBC and LS control functions in the analog system can be merged into a cost-effective digital controller. To compensate and stabilize PSFBC and LS loops with the direct digital design approaches, a small-signal model of the overall system is derived in the discrete-time domain successively. Then, the steady-state and dynamic load sharing performances are also investigated. Experimental results from two identical 1.2 kW paralleled PSFBC modules are presented to verify the proposed work.