Dual‐transformer soft‐switching DC–DC resonant converter with multiple resonant elements

Abstract

A novel dual-transformer DC-DC converter with multiple resonant elements is proposed. Owing to the multi-resonant feature, the converter is able to achieve a wide DC voltage gain range through the proper selection of resonant parameters. The operating frequency is restricted within a narrow scope. The potential high-frequency losses are avoided, which apparently contributes to efficiency improvement. Besides, since the proposed converter contains more resonant frequencies, it is possible to additionally transmit the third-order active power to the load. All the power switches have realised the turn-on soft-switching, while the diodes obtain the soft-switching or quasi-soft-switching for both the turn-on and turn-off periods. To verify the theoretical analyses, a 500 W prototype is established in the laboratory. The experimental results demonstrate that the proposed converter can maintain relatively high efficiency (∼95%) among a wide load range. The highest efficiency reaches 95.4% at 300 W.

Soft‐switching DC–DC converter with controllable resonant tank featuring high efficiency and wide voltage gain range

“…where M ReLLCn and M ImLLCn represent the corresponding nth-order components of M ReLLC and M ImLLC , respectively. From (11), it infers that at the rating condition, high-order active power and reactive power also exist in the resonant tank of the LLC circuit.…”

“…So far, large quantities of works have been implemented on this kind of converters. They are mainly concentrated on the parameter design [7][8][9][10], topology development [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], control strategies [28], and high-frequency applications [29]. One of the most important issues these literature foci on is how to pursue a wide voltage gain range on the premise of high efficiency.…”

State‐space modelling of LLC resonant half‐bridge DC–DC converter

“…With this advantage, the power converter can operate at high switching frequency which, in turn, leads to significant size reduction of the passive devices such as tank inductor and output filtering capacitor. Consequently, higher conversion efficiency and better power density of the system can be achieved [3][4][5][6].…”

High‐efficiency topology‐morphing multi‐resonant DC–DC converter with wide voltage gain range for small‐scale wind generation applications

“…Owing to the diversity of topologies, the MRCs can be divided into several types, namely the four-element type [20][21][22], the fiveelement type [23][24][25], the high-order type, the topology-morphing type [26,27], and the multi-transformer type [28][29][30][31][32]. An inductor-capacitor-inductor-capacitor resonant tank is employed in [20] for the step-up use.…”