Virtual Fractional-Order-Inductor Based Second Harmonic Current Suppression Method
Hongyan Zhou, Liangzong He, Zelong Yang, Zhile Lin
Abstract
In a two-stage single-phase inverter, the pulsating output power generates a second harmonic current (SHC) at the dc port. Although the conventional virtual-resistor (VR) based control method can suppress the SHC, the SHC reduction performance is limited by its dynamic performance. To address the above issues, based on the unified small-signal model of the dc–dc converter, a virtual fractional-order-inductor (FOI) based control method is proposed in this article to reduce the SHC and improve the system dynamic performance. The order and magnitude of the fractional-order inductor can be modified arbitrarily. A negative order inductor is constructed in this article to reduce the SHC and improve the system dynamic performance. In addition, the proposed virtual FOI-based control method can improve the stability of both dc–dc converter and the cascaded system. The comparison of the proposed fractional-order inductor and conventional VR-based control method is given and the design method of key parameters is presented. Finally, an 800-W two-stage single-phase inverter with the upstream boost converter is fabricated and tested in the laboratory to verify the effectiveness of the proposed control method.