A High-Performance Dynamic Controller For an Active Power Decoupler With AC-Side Storage Element

Abstract

The instantaneous power in a single-phase system pulsates at double the supply frequency. With the effective use of the storage element, the electrolytic capacitor placed at the dc bus can be replaced by film capacitors, thereby improving the converter lifespan. Active power decoupling (APD) using an extra set of switches aims to attain the same. Recently, a promising APD topology has been reported, offering a lesser number of switches, as well as lesser stress on the switches for a wide range of power factor. However, the control of that converter poses a challenge as it has more number of states than the independent control variables. This paper focuses on the control aspect of the topology. It is shown that controlling two out of three states guarantees the overall system performance at the steady state. Also, ripple power in the dc bus is controlled in a closed-loop fashion so as to handle model uncertainty and thereby improve the steady-state performance. Furthermore, the solution to suppress the harmonic power, reflected on to the dc bus, under polluted grid condition is provided. The simulation and experimental results are presented supporting the analysis and design of the controller structure.