Current-Stress Reduction for the Neutral Inductor of $\theta$ -Converters

Following the recently proposed θ-converter that reduces voltage ripples, leakage currents, and total capacitance required in a single-phase converter, this paper further improves the θ-converter by reducing the current stress of the neutral inductor, by relocating it to the dc side without affecting the other functions of the θ-converter. Based on the average circuit model of the proposed converter, it is found that the current flowing through the neutral inductor can be reduced by at least three times, and hence, the size of the inductor can be reduced by at least nine times. How to operate the converter to achieve the reduction of the current stress is discussed in detail. Moreover, the selection criteria on the neutral inductor and other passive components used in the proposed converter are discussed in order to minimize their usage. Intensive experimental results are presented to demonstrate that the proposed converter can indeed reduce the current-stress while the other functions of the θ-converter are not affected.