Parallel Operation Control of a Single-Phase High-Frequency Isolated Inverter

In this article, a simplified active clamping circuit is proposed, and its corresponding modulation strategy is developed, which can effectively suppress the transformer secondary-side output voltage spikes. Meanwhile, this clamping circuit provides additional commutation paths for the secondary-side leakage inductance current and filter inductor current, thereby avoiding voltage overshoot. The circuit modes are analyzed in detail, and the boundary conditions for switches to achieve zero-voltage switching (ZVS) and their conduction losses are given. Finally, based on the special circuit structure of the isolated inverter, a single-phase high-frequency isolated inverter parallel experimental prototype is constructed, and the corresponding control strategy is presented. The experimental results show the excellent voltage spike suppression capability of the simplified active clamping circuit. The droop control with strong robustness can further improve the power distribution performance of the isolated inverter parallel system, and the reactive power of the parallel system is significantly reduced.