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

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.

Practical Dead-Time Control Methodology of a Three-Phase Dual Active Bridge Converter for a DC Grid System

“…In this paper, the phase shift difference between two bridges, the HVS, and the LVS is defined to the normalized term ɸPSM (=ɸ/π), and this term controls the transmission power. A six-step phase voltage waveform of each bridge, the HVS, and LVS is generated under the steady-state operation [10,16]. In this paper, several assumptions are also considered for the analysis as follows: …”

“…In [15], a variable switching frequency control algorithm was applied to the 3P-DAB converter to improve power conversion efficiency. In [16], based on the small signal model of the 3P-DAB converter, the design methodology for a practical controller is proposed. Although there are lots of papers on 3P-DAB converters, most of them focus only on hardware For these reasons, attention is focused on the key concept of grid forming [3].…”

Eco-Dimensioning Approach for Planar Transformer in a Dual Active Bridge (DAB) Application

“…The DAB has become a popular DC-DC converter over the last ten years that allows galvanic isolation, bidirectionality in power, symmetricity, controllable output, high power density, and efficiency. Due to such exceptional performance and features, it is mostly used in renewable energy systems [13,14], energy storage systems [15], DC distribution systems [16], and solid-state transformer (SST) [17]. The topology is presented in Figure 3.…”

“…The DC resistance basic equation is presented in (16). However, besides depending on the number of turns and core geometry, it will also depend on the winding technology.…”