Modelling and controller design of inductor-coupled multimodule DC-DC convertor with master-slave current-comparing scheme

The paper proposes a novel multimodule parallel structure with coupled inductor and common filter. The design and implementation of a three-module parallel push-pull convertor system is presented. In parallel operation, a master-slave current-comparing scheme is proposed to compensate the mismatch in current-control characteristics of each parallel convertor. First, the small-signal equivalent circuit and transfer-function model of the multimodule convertor system are found. Then the model reduction is performed using the concept of dominant energy mode. Based on the reduced convertor model, a PI controller is quantitatively designed according to the prescribed regulating specifications. The performance of the convertor and the effectiveness of the proposed controller are demonstrated by some simulation and experimental results.