Thermal balancing of multiphase resonant converters controlled by phase shift

Phase shift modulation of multiphase class D resonant converters inherently results in an uneven current distribution among the sections. This leads to a thermal imbalance within the transistors and inductors. Branches with higher temperatures negatively impact the efficiency due to the temperature dependence of the resistance in wires and devices. In this work, a new operation mode of the converter is proposed that equalizes the current distribution of the class D sections and greatly reduces temperature imbalances within transistors and inductors. This proposal involves periodically exchanging the control signals of the inverter sections, which does not affect the control of the output variables due to the symmetrical structure of the circuit. The proposal is validated using a four-phase LC
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resonant converter designed for a Lithium-ion battery charger application.