Analysis and Design of a Bidirectional High Step-up Active Clamp Flyback Converter for Dielectric Elastomer Actuator

Dielectric elastomer (DE) is a kind of capacitive material that widely used in soft robots' applications as actuators. To obtain notable deformation, the drive voltage is typically up to several thousand volts and the charging charges must be removed to make it recover. In this paper, a high step-up capacitive load bi-directional flyback converter with active clamp technique is proposed. For the charging process, the effects of increasing high output voltage and parasitic elements in the circuit on the operation of the active clamp circuit are discussed in detail. Wide bandgap devices are used at the secondary side to reduce the parasitic capacitance. The proposed lossless active clamp circuit can absorb the energy in leakage inductance of transformer and achieve zero-voltage-switching (ZVS) over most of the charging process. Besides, the EMI problem caused by leakage inductance of conventional flyback converter is also solved. A prototype with 12V input and 1000V output has been fabricated and compared with a quasi-resonance flyback (QR flyback) at the same working condition. The tested results verify the good performance of the proposed ACF converter.