An integrated interlinking converter with DC-link voltage balancing capability for bipolar hybrid microgrid

Abstract

The bipolar hybrid microgrid is a newly emerged structure which has gained increasing attention during the last decades. The heart of this structure is the interlinking converter that plays a crucial role in this system and has three main functionalities: (1) bidirectional connection between AC and DC subsystems, (2) sinusoidal current injection with desired power factor to AC side and (3) providing two buses with equal voltages in DC side. This paper applies a recently proposed ten-switch inverter as an interlinking converter in the bipolar hybrid microgrid that can increase efficiency, reliability and power quality on AC and DC sides in such systems. Ten-switch converter has lower cost, volume and size compared to the conventional interlinking converters. A new modulation and control strategy is proposed for ten-switch converter in the bipolar hybrid microgrid which, unlike conventional systems, does not need any extra hardware as a voltage balancer converter to balance DC-link pole voltages. The effectiveness of the proposed modulation and control strategy of ten-switch converter is evaluated and compared with conventional structures in a simulation study. Adaptive power loss calculations and cost analysis are conducted and then compared with three interlinking converters candidates to show the superiority of the proposed interlinking converter.