Active Power Decoupling Control for Three-Level Buck Four-Leg Current Source Inverter

Significant pulsating power exists on the dc side of three-phase four-wire inverters in the case of unbalanced or nonlinear loads, which will degrade the power quality of the dc side voltage. To address this issue, this article presents an active power decoupling control scheme for a three-level buck four-leg current source inverter topology. By fully utilizing the flying capacitor converter, this scheme can effectively buffer the pulsating power into the flying capacitor without modifying any hardware circuit and suppress the pulsating input current. In addition, a virtual resistor scheme is adopted to improve the stability of the converter. The experimental results validate the effectiveness of the proposed method.