Research on Non-Isolated Bidirectional Four-Port DC-DC Converter and Its Control Strategy

doi:10.11930/j.issn.1004-9649.201702043

Abstract

Abstract: The paper proposes a non-isolated four-port bidirectional DC converter based on bidirectional buck-boost converter, to accommodate the needs of power flow confluence, distribution and voltage conversion. The proposed DC converter enhances the efficiency and power density by achieving voltage step-up through a single process. Compared with the conventional practice where multi-port converters are connected with a common AC or DC bus, the proposed design sees reduction in both volume and costs and improvement in reliability by eliminating the DC capacitor and AC transformer. In the converter, any selected pair of input and output ports can be considered as a buck-boost unit, there is no coupling among different units in terms of power circuits. Therefore, it is easy to be realized. After analyzing the operational mechanism of the proposed DC converter, a four-terminal bipolar DC transmission system is established in PSCAD/EMTDC, to demonstrate and validate the effectiveness of the proposed DC converter. An example device is also developed for the purpose of further validation. Simulation results suggest that the proposed DC converter can perform the task of power flow distribution and voltage step-up.

Key words: power flow regulation, DC-DC converter, bipolar DC grid, flexible HVDC, bidirectional buck-boost converter

CLC Number:

TM46

CUI Hongfen, YAO Liangzhong, SANG Bingyu, YANG Bo, TAO Yibin. Research on Non-Isolated Bidirectional Four-Port DC-DC Converter and Its Control Strategy[J]. Electric Power, 2018, 51(10): 56-63.

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URL: https://www.electricpower.com.cn/EN/10.11930/j.issn.1004-9649.201702043

https://www.electricpower.com.cn/EN/Y2018/V51/I10/56

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