A Parallel Dual LLC Resonant Converter with Wide Output Voltage Range for Energy System Applications

This paper proposes a half-bridge parallel dual LLC resonant converter with wide output voltage range. The proposed converter uses a conventional parallel double half-bridge LLC resonant converter. On the primary side of the converter, only one of the two half bridges is used to control the two resonant loops. Due to the resonance of the converter, the active switches can achieve ZVS (zero-voltage switching), and the rectifier diode can also achieve ZCS (zero-current switching), and thus the switching loss is reduced. The current stress can be reduced and power can be distributed on both of the primary side and/or the secondary side. A voltage regulation circuit is designed on the secondary side to achieve the function of wide output voltage. The operation and analysis of the proposed converter are described in detail. The experiments were carried out on a circuit prototype, which is a converter with DC input voltage of 384 V and output voltage of 24–40 V and operating at a switching frequency of 107 kHz. The feasibility and performance of the proposed converter were verified by simulation and experimental results.