Differential Mode Y-Source DC-DC Converter for Better Performance with Loosely Coupled Inductors

Abstract

Magnetically coupled inductor based impedance source dc-dc boost converters are capable of producing high voltage boost with reduced components and low shoot-through duty ratios (STDR). A Y-source converter (YSC) is one of the prominent topologies in the family of magnetically coupled impedance networks, which offers the highest degree (three degrees) of freedom to the controller to maintain constant output voltage compared to the former magnetically coupled Z-source topologies. However, YSC requires tight coupling (nearly unity) among three coupled windings to generate high voltage boosting. But, the continuation of tight coupling is quite difficult in the design of offline YSC when it involves high switching frequency operations. The leakage inductances are common in the design of any magnetically coupled topologies under high operational frequencies. High voltage overshoots, voltage boost degradations are the consequences of the leakage inductance with loosely coupled inductors. This paper attempts to analyse the effect of leakage inductances mathematically with detailed circuit representation of coupled inductors. In addition, a differential mode Y-source converter (DYSC) is proposed which is derived from the former Y-source network by changing the winding orientation. The performance of the proposed DYSC is analyzed using Matlab/SimulationsTM and also compared with YSC. The hardware results are presented to validate the theoretical simulations of both YSC and DYSC topologies. � 2018 IEEE.