Adaptive Output Current Ripple Reduction Control of Interleaved LLC Converter Based on Time Domain Analysis

Interleaving technology is widely used in LLC converters due to its high power capacity and advantage of current ripple cancellation. Introducing phase-shift modulation (PSM) for current sharing control while maintaining the same switching frequency for all phases can achieve current ripple cancellation without additional auxiliary devices and topologies. Traditional interleaved LLC converters typically employ fixed <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$180^{\circ} / \mathrm{n}$</tex> phase interleaving angles, which fail to achieve optimal output current ripple suppression with resonant parameters deviation between different phases. Taking a two-phase interleaved LLC converter as an example, this paper proposes an optimal interleaving angle control method based on timedomain analysis by locating the point of peak rectifier current. Simulation results demonstrate a maximum 55% reduction in peak-to-peak output current ripple. The proposed control strategy is also applied to a 1 kW two-phase interleaved LLC converter with 180 V output voltage, which shows a peak-topeak output current reduction compared to traditional fixed interleaving angle strategy.