Optimal Asymmetric Duty Modulation to Minimize Inductor Peak-to-Peak Current for a Dual Active Bridge Converter Over a Wide Voltage Range

Conventionally, the phase-shift modulation (PSM) scheme is the simplest modulation scheme for a dual active bridge (DAB) converter, which only needs to control one variable to realize bidirectional power flow. However, when the input or output voltage of the converter varies widely, a large amount of reactive power is generated and the zero-voltage switching (ZVS) operation cannot be realized, which ultimately results in low efficiency. Asymmetric duty modulation (ADM), as a recently proposed modulation scheme, provides new chances to improve the performance of the DAB converter. On this basis, an optimal asymmetric duty modulation (OADM) scheme is proposed in this paper by minimizing the inductor peak-to-peak current over the whole voltage and power range. Finally, an experimental prototype was built to validate the efficiency improvement of the converter by the proposed OADM scheme.