非对称占空比调制下 DAB 损耗方差优化策略

The asymmetric duty cycle modulation (ADM) strategy can solve the problem of low system efficiency in dual active bridge (DAB) under light load conditions. However, ADM can cause large difference of DAB switch loss distribution, high risk of thermal stress and system reliability. To solve the above-mentioned problems, an asymmetric duty cycle modulation optimization strategy based on minimal variance of switch loss was proposed. The power transmission and soft switching range of ADM were analyzed, and the device loss model under ADM was established, with minimal variance of DAB switch loss as the optimization target, and optimal control combinations were obtained using particle swarm optimization algorithm. Finally, a DAB prototype with 1. 6 kW capacity and SiC MOSFET was tested. The feasibility and validity of the optimized modulation method were verified by taking the peak and variance of device temperature as evaluation index. Under the light load conditions of 330 W and 500 W, the device temperature variance of the optimized scheme is reduced by 43% and 21. 5%, the peak temperature is reduced by 2. 8 ℃ and 0. 6 ℃, and the system efficiency is improved by 1. 2% and 0. 5%, respectively.