Full-load Range ZVS Achievement by Using Both Burst Mode and PWM With Variable Frequency Modulation for DAB Converters

This paper investigates the use of both burst mode and pulse width modulation (PWM) to improve the performance of dual active bridge (DAB) converters. By incorporating inactive intervals in each switching cycle, a burst mode operation can regulate the output power of a DAB converter without causing a significant efficiency drop. However, hard switching operations can happen during the transient process of active and inactive intervals of a typical burst mode for the DAB converter. In addition, a long inactive interval can significantly decrease switching frequency; therefore, it can increase audible noise, high voltage ripple of dc-link capacitor, and degrade the control capability. This paper proposes an improved modulation scheme for DAB converters using both PWM and burst mode to achieve zero voltage switching (ZVS) in full-load range, while avoiding an excessive decrease in switching frequency. The proposed control strategy is verified through experimental results on 3.3-kW DAB prototype.