Practical Controller Design of Three-Phase Dual Active Bridge Converter for Low Voltage DC Distribution System

Hyun-Jun Choi,Won-Bin Lee,Jee-Hoon Jung

doi:10.3390/electronics9122101

Hyun-Jun Choi, Won-Bin Lee + Show 1 more

Open Access

https://doi.org/10.3390/electronics9122101

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Abstract

In a low voltage DC (LVDC) distribution system, isolated bi-directional DC-DC converters are key devices to control power flows. A three-phase dual-active-bridge (3P-DAB) converter is one of the suitable candidates due to inherent soft-switching capability, low conduction loss, and high-power density. However, the 3P-DAB converter requires a well-designed controller due to the influence of the equivalent series resistance (ESR) of an output filter capacitor, degrading the performance of the 3P-DAB converter in terms of high-frequency noise. Unfortunately, there is little research that considers the practical design methodology of the 3P-DAB converter’s controller because of its complexity. In this paper, the influence of the ESR on the 3P-DAB converter is presented. Additionally, the generalized average small-signal model (SSM) of the 3P-DAB converter including the ESR of the capacitive output filter is presented. Based on this model, an extended small-signal model and appropriate controller design guide, and performance comparison are presented based on the frequency domain analysis. Finally, experimental results verify the validity of the proposed controller using a 25 kW prototype 3P-DAB converter.

Highlights

Interests in applications for DC grids have recently increased [1,2,3]
The equivalent series resistance (ESR) zero can be reduced through practical hardware design methods and parallel/series connection; it cannot be vulnerable to high power density applications and this method has low cost-efficiency
Simulated transient responses of the 3P-DAB converter using the theoretical model in the time-domain

Summary

Introduction

Interests in applications for DC grids have recently increased [1,2,3]. To configure the DC microgrid, which can replace the conventional alternating current (AC) distribution system, the low voltage DC (LVDC) distribution system has been steadily studied and examined [4,5,6]. To develop the LVDC system, the IBDC converter is essential, linking the LVDC grid to DC end users. The IBDC converter is required to convert the high voltage level in the distribution system to the low voltage level required by the applications, which is commonly designated as 380 V [7]. The suitable candidates for the LVDC converter should treat several hundred DC voltage levels in a smooth bi-directional control manner.

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Results

Conclusion