Current Equalization Strategy for Three-Phase LLC Converter Based on Integral Phase-Shift Control

With the rapid development of the new energy industry, the demand for high-performance power electronic devices is growing. The three-phase interleaved parallel LLC resonant converter has been widely used due to its characteristics such as high power density, low electromagnetic interference, high efficiency, wide input range, small output current ripple, and low component stress. However, differences in resonant parameters among the modules of the three-phase LLC converter may lead to uneven distribution of load currents. This paper proposes a novel control strategy suitable for the three-phase interleaved parallel LLC converter. The method controls by comparing the relationship between the three-phase resonant currents and adjusting the sizes of two phase-shift angles, thereby influencing the amplitude of the voltage fundamental wave. In this way, the resonant currents of the three phases can be balanced, achieving load current balance in the three-phase LLC converter. Finally, the effectiveness of this integral phase-shifting control strategy is validated through simulation and experimentation.