HV DAB using loss-minimizing burst sequences for feeding DE transducers

This paper introduces a cost-efficient variant of the dual active bridge (DAB) suitable for bidirectional driving of resistive-capacitive loads such as dielectric elastomer transducers (DET) at high output voltages. The blocking voltages of the used HV switches are significantly reduced by using two cascaded HV half bridges on the secondary side. The authors derive a model for calculating the current and voltage waveforms of the proposed converter. The DAB’s steady-state operation is discussed, and a way of choosing optimal switching patterns is shown. These patterns enable the bidirectional operation of the converter at low switching and conduction losses. To improve efficiency under light-load conditions, the authors present a control strategy based on an advanced burst mode considering the challenges imposed by the converter’s high output voltages. Measurements using an experimental prototype validate the model and demonstrate the advantages of this converter topology and the proposed burst-mode control.