Phase-shifted modulation strategies for a single-stage isolated bi-directional power amplifier

A Single-Stage isolated bi-directional power amplifier (SSA) is proposed which achieves high level of integration, high efficiency and low component without bulky dc link capacitors. The SSA comprises an input active bridge and an output cycloconverter with an active clamper circuit, linked by a high-frequency isolation transformer. The uni-polarity and bi-polarity phase-shifted modulation strategies are deeply and comparatively investigated. The operation principles of zero voltage switching (ZVS) and duty cycle loss are analyzed and derived specifically. The simulation and experimental results on a 80W single stage amplifier are presented to validate the theoretical analyses and operation principles.