Novel Boost-SEPIC Type Interleaved DC–DC Converter for Mitigation of Voltage Imbalance in a Low-Voltage Bipolar DC Microgrid

Abstract

Despite its many desirable features, a bipolar dc microgrids (BDCMG) requires a large number of conventional dc-dc converters to feed power to its two poles. Besides, the BDCMG is also prone to voltage imbalance due to unequal load distribution across its two poles. To overcome these issues, this article presents a novel nonisolated boost-SEPIC type interleaved (BSTI) dc-dc converter topology that enables power from a single source to be fed into the two poles of the BDCMG, thereby, reducing the total number of converters in the system. The proposed converter can support bidirectional operation with synchronous rectification. Furthermore, the input current ripple is low due to interleaved operation. A novel method to mitigate the voltage imbalance in a BDCMG using BSTI converter is also proposed. In the proposed method, the neutral line-current in the BDCMG is reduced, thereby, decreasing the overall line-losses. The BSTI converter operates as a dc compensator (like STATCOM in ac systems), where, apart from the converter losses it does not supply or consume any active-power. Hence, no active source (e.g., battery) is required for mitigating the voltage imbalance. Detailed theoretical analysis and experimental results are presented to validate the efficacy and feasibility of the proposed schemes.