Analysis and Design of High-Efficiency Bidirectional GaN-Based CLLC Resonant Converter

Abstract

A bidirectional CLLC resonant converter (CLLC-BRC) based on GaN transistors is analyzed and designed in this paper. Similar resonant topologies are listed and commented on, with the CLLC topology showing competitiveness in bidirectional energy transmission. The analysis of the aforementioned converter has been provided, including the reveal of resonant frequencies of the CLLC topology and an improved zero-voltage switching (ZVS) condition with operation principles of the reverse mode and relevant parasitic parameters taken into account. The design methodology of the aforementioned converter based on pulse frequency modulation (PFM) is further discussed in detail. A prototype with a rated power of 400 W and a maximal operating frequency that is larger than 0.5 MHz was built to verify the proposed design methodology. The highest conversion efficiency of the prototype was 97.02% in the forward mode, and it was 95.96% in the reverse mode.

Design of a Bidirectional CL3C Full-Bridge Resonant Converter for Battery Energy Storage Systems

“…Because a converter can adjust the output voltage by using its resonant tank and transformer, the turns ratio N must be defined to determine the maximum and minimum gains required by the transformer and expedite the subsequent design process. The turns ratio is expressed in Equation (8).…”

“…Thus, ZCS is impeded at the rectifier side, which reduces the converter efficiency. Consequently, LLC resonant converters are unsuitable in scenarios where reverse voltage step-up is required [8].…”

Implementation of a Resonant Converter with Topology Morphing to Achieve Bidirectional Power Flow

“…The Energies 2021, 14, 5186 2 of 21 primary and secondary sides of the isolated transformer are symmetric to ensure that the voltage transfer functions for both the forward and backward power operations are similar. In [12,14], the full bridge based bidirectional resonant converters were presented for DC power distribution. The bidirectional resonant converters are easy to implement by using the analog or digital control algorithm to realize a voltage step-down or step-up operation.…”

High Power Density, High-Voltage Parallel Resonant Converter Using Parasitic Capacitance on the Secondary Side of a Transformer

“…However, such a high-voltage power supply has problems, such as a decrease in reliability owing to an increase in output ripple voltage and a decrease in power density owing to an increase in volume. Consequently, several studies have been conducted in order to reduce the output voltage ripple or improve the power density and to ensure the miniaturization, high efficiency, and reliability of high-voltage DC power supplies [1][2][3][4][5][6][7].…”

“…However, if the switching frequency is increased, the efficiency of the system generally decreases, owing to the high switching loss, and the heat dissipation design becomes difficult. In [7,8], the authors proposed methods to reduce the size of passive components, such as resonant inductors, transformers, and capacitors, by increasing the switching frequency through applying wide-bandgap (WBG) switching components. In this case, the switching loss did not increase significantly, owing to the fast-switching characteristics of the WBG switching element.…”