Enhanced Automatic-Power-Decoupling Control Method for Single-Phase AC-to-DC Converters

Abstract

Existing control schemes for single-phase ac-to-dc converters with active power-decoupling function typically involve a dedicated power-decoupling controller. However, due to the highly coupled and nonlinear nature of the single-phase system, the design of the power-decoupling controller (typically based on the linear control techniques) is cumbersome, and the control structure is complicated. Additionally, with the exiting power-decoupling control, it is hard to achieve satisfied dynamic responses and robust circuit operation which are required for a reliable system operation. Following a recently proposed automatic-power- decoupling control scheme, this paper proposes a nonlinear control method that can achieve enhanced dynamic responses with strong disturbance rejection capability without the need for a dedicated power-decoupling controller. The proposed controller has a simple structure, of which the design is straightforward. The control method can be easily extended to other single-phase ac-to-dc systems with active power-decoupling function. Simulation and experimental results validate the feasibility of the proposed control method on a two-switch buck-boost PFC rectifier prototype.