Bidirectional Isolated Dual-Active-Bridge (DAB) DC-DC Converters Using 1.2-kV 400-A SiC-MOSFET Dual Modules

 ABSTRACT:

 This paper describes the 750-Vdc, 100-kW, 20- kHz bidirectional isolated dual-active-bridge (DAB) dc dc converters using four 1.2-kV 400-A SiC-MOSFET dual modules with or without Schottky barrier diodes (SBDs). When no SBD is integrated into each dual module, the conversion efficiency from the dc-input to the dc-output terminals is accurately measured to be 98.0% at the rated-power (100 kW) operation, and the maximum conversion efficiency is as high as 98.8% at 41-kW operation, excluding the gate drive and control-circuit losses from the total power loss. The bidirectional isolated DAB dc-dc converters are so flexible that series and/or parallel connections of their individual input and output terminals make it easy to expand the voltage and current ratings for various applications such as the so-called “solid-state transformer” or “power electronic transformer.”

KEYWORDS:

1.      Bidirectional isolated dc-dc converters

2.      Conversion efficiency

3.      Dual-active-bridge configuration

4.      SiC MOSFET modules

SOFTWARE: MATLAB/SIMULINK

CONCLUSION

This paper has designed, built, and tested two 750-Vdc, 100-kW, 20-kHz bidirectional isolated dual-active-bridge (DAB) dc-dc converters using four 1.2-kV, 400-A SiC-MOSFET dual modules with and without SBDs are used, the maximum conversion efficiency from the dc- input terminals to the dc-output terminals is as high as 98.8. at 41 kW, and 98.0% at 100 kW, which are calculated from the accurately-measured overall power loss excluding gate drive and control circuit losses. When the next generation trench-gate Sic-MOSFET modules come across, the conversion efficiency of a well designed DAB dc-dc converter is expected to be higher than 99% in a broad power range, even at the rated power. Series and/or parallel connections of multiple DAB dc-dc converters would make it easy to expand the voltage and/or current ratings as if the converter were operating as a single high-power DAB dc-dc converter. In particular, the input series and output-parallel connections show considerable promise as a dc-dc converter for medium-voltage high power battery energy storage systems and an interface circuit between two dc power networks with different dc voltages.

REFERENCES:

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