Single-Phase Current-Source Grid-Connected Inverter Based on Boundary Voltage Control

A boundary voltage control (BVC) strategy suitable for single-phase current-source inverters has been proposed to achieve zero current switching (ZCS) by dynamically adjusting the resonant capacitor voltage, and this control strategy has low requirements for DC side current ripple, which can effectively reduce the DC side inductance value. Therefore, this control method can reduce circuit losses and decrease the size of the inverter. In this article, the working principle and conditions for achieving ZCS are analyzed by combining BVC and bipolar modulation strategy; Based on the principle of area equivalence, a quantitative model of DC side inductor current and output current is established, revealing the mechanism of the impact of second harmonic current ripple on output harmonics. The optimization design criteria for DC side inductance parameters are derived, and the reasons for the decrease in inductance value are analyzed. On this basis, a three loop grid-connected control strategy based on BVC is proposed. Finally, based on theoretical analysis, simulation and experimental research are conducted. The simulation and experimental results have verified the feasibility of the proposed BVC strategy.