A Seamless Thermal Balance Control Strategy for Asynchronous Parallel Half-Bridge Circuit

Abstract

The asynchronous parallel half-bridge circuit has the characteristics of reliable capacity expansion and easy realization of zero-voltage switching, which can be a promising candidate for large capacity converters using wide bandgap devices. However, it has the issue of heat concentration, which leads to severe thermal imbalance and high thermal stress, posing a challenge to thermal design. In this letter, thermal balance control strategy is utilized by exchanging the drive signals of two-phase circuits, which can periodically change the loss distribution among the switches, suppressing the above problem. By compensating for the current variation, it effectively eliminates current overshoot and oscillation during transition, thereby mitigating inductor saturation and enhancing the reliability of the system. Furthermore, a thermoelectric coupling analysis method is proposed to evaluate the performance of the converter and provide guidance for converter design. Experimental and simulation results have been presented to demonstrate the effectiveness of the proposed solution.