An Autonomous Current Balancing Method for Interleaved DC/DC Converter in Wireless Power Transfer Systems

Interleaved dc/dc converters are commonly used in high-power wireless power transfer (WPT) systems to manage the high charging currents and voltages. However, interleaved dc/dc converters in these systems suffer from current imbalances, causing inefficiencies and unreliability due to uneven thermal distribution and current stress. In this article, an autonomous current balancing method is proposed for two-phase interleaved dc/dc converter-based WPT systems with a split input configuration. The method is mathematically proven to be generally applicable to WPT systems with interleaved dc/dc converters, enabling flexible deployment across applications with varying power levels, load conditions, and converter configurations. A small-signal model-based control strategy is developed to ensure fast dynamic responses and high robustness of the system against disturbances. The proposed method is validated through mathematical analysis, simulation comparisons, and laboratory experiments, confirming its effectiveness in both steady-state and dynamic operations of the WPT system.