Adaptive Hysteresis Comparison Control of Load Sharing for Three-Phase Interleaved SCC-LLC Converter

It is desirable to connect several LLC converters in parallel in high-power and/or high-current applications. However, component tolerance among resonant tank of different phases causes severe unbalanced load sharing, leading to performance degrading. In this paper, full-wave Switch-Controlled Capacitor (SCC) is added into resonant tank to compensate component tolerance and to achieve load sharing. An adaptive hysteresis comparison control scheme is proposed to adjust SCC angle α for current sharing. The proposed control strategy only occupies few digital controller resources; thus, low-cost Micro-Controller Unit (MCU) can be used. Experimental results of a 250V - 430V input, 14V/260A/3.6kW output, three-phase interleaved SCC-LLC EV DC-DC converter demonstrate the effectiveness and feasibility of the proposed method.