Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title Improvement of Power Unbalance Problem due to Distributed Design of Isolated Bidirectional DC-DC Converter for High Voltage
Authors Seong-Taek Oh ; Hyuk-Jin Kwon ; Jeong-Uk Park ; Seing-Won Choi ; Il-Oun Lee ; Jun-Young Lee
DOI 10.6113/TKPE.2021.26.2.82
Page pp.82-89
ISSN 1229-2214
Keywords High voltage DC-DC converter; DAB converter; Power unbalance; Flying capacitor; CMCI
Abstract This study proposes a DAB two-stage series structure with insulated bidirectional DC?DC converter for two-way power transfer between the renewable energy of high voltages (1 kV and above). The proposed circuit transforms the existing DAB converter into a two-stage series structure to reduce the pressure in the switch. The problem of power imbalance occurring in the design of the DAB converter second-stage series is improved by applying the cell balancing method circuit and the common mode coupled inductor using an external flying capacitor instead of reflecting the existing improvement measures, voltage balance control, and inductor current control. In addition, a no-load supercharging sequence is proposed in high voltages and high-speed switching by using the fixed duty output method. This study presents the analysis results through the structure of the proposed circuit, the principle of improving the power imbalance problem, and simulations. Prototypes were manufactured to meet the specifications of input/output voltage of 1700 V, maximum load of 65 kW, and switching frequency of 51kHz, and the validity of the topology was verified using the experimental results and efficiency data.