High-efficiency Bidirectional Buck–Boost Converter for Residential Energy Storage System

Abstract

This paper proposes a bidirectional dc–dc converter for residential micro-grid applications. The proposed converter can operate over an input voltage range that overlaps the output voltage range. This converter uses two snubber capacitors to reduce the switch turn-off losses, a dc-blocking capacitor to reduce the input/output filter size, and a 1:1 transformer to reduce core loss. The windings of the transformer are connected in parallel and in reverse-coupled configuration to suppress magnetic flux swing in the core. Zero-voltage turn-on of the switch is achieved by operating the converter in discontinuous conduction mode. The experimental converter was designed to operate at a switching frequency of 40–210 kHz, an input voltage of 48 V, an output voltage of 36–60 V, and an output power of 50–500 W. The power conversion efficiency for boost conversion to 60 V was ≥98.3% in the entire power range. The efficiency for buck conversion to 36 V was ≥98.4% in the entire power range. The output voltage ripple at full load was <3.59 Vp.p for boost conversion (60 V) and 1.35 Vp.p for buck conversion (36 V) with the reduced input/output filter. The experimental results indicate that the proposed converter is well-suited to smart-grid energy storage systems that require high efficiency, small size, and overlapping input and output voltage ranges.

A Novel Bidirectional DC-DC Converter for Dynamic Performance Enhancement of Hybrid AC/DC Microgrid

“…Substituting coefficients (10) into (17) for the charge mode using the rated values of load resistance R ch l and input voltage E ch 1 in (18) and (19) yields…”

“…However, this configuration was an improved version of the half-bridge converter, making only a slight improvement only in voltage gain at the cost of additional components with a control design working asymmetrically for both modes. The nonisolated converter in [13] and its improved high-efficiency topology in [19] provided soft-switching operation, employing a 1:1 ideal transformer and pulse-frequency modulation to accommodate load variation and reduced switching loss and to achieve high efficiency. The implemented digital controller used a single loop Proportional-Integral (PI) controller that worked for both modes, with applications in residential energy storage systems.…”

Active power compensator for a DC voltage bus of a renewable source

“…A typical configuration of a power compensator uses a bidirectional DC-DC converter in conjunction with a battery bank for delivering power to a DC bus of a renewable power source when it does not meet the contracted energy demand. The Buck-Boost DC-DC converter controlled by PWM (pulse width modulation) signals has been used in DC-DC power converter applications (Guerra et al, 2021;Ham et al, 2019;Lopez-Garcia et al, 2018;Viswanatha & Venkata, 2018). The controllers of DC-DC Buck-Boost converters may be as simple as using comparators (Viswanatha & Venkata, 2018) or as complex as incorporating intelligent systems (Lopez-Garcia et al, 2018), and most of them regulate output voltage instead of power.…”

Optimal Design of LLC Resonant DC Transformer under Adaptive Frequency Tracking Strategy

“…However, its ZVS range is limited, and the switch also has a high turn-off current, resulting in a reduction in power conversion efficiency [5]. Even if the performance of the circuit can be improved by other modulation strategies, the complexity of the system control will increase accordingly [6]. The LLC resonant converter can achieve soft switching characteristics in…”