Peak Current Control of Swiss Rectifiers in Unbalanced Grids

Swiss rectifier as a new type of step-down rectifier is widely used in electric vehicle charging pile, aviation power supply. Aiming at the problems of dc-side voltage fluctuation, ac current distortion, and current peak overrun of Swiss rectifier during grid voltage imbalance. This paper firstly analyzes the two control objectives of voltage/current in <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{dq}$</tex> rotating coordinate system, and invokes the coordination coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{k}$</tex> to realize the multi-objective flexible control. Secondly, this paper proposes an improved peak current protection module with peak fast detection method and remodulation of the inner loop current. In summary, a multi-objective coordination method for Swiss rectifier considering current peaks is obtained, which ensures that the system does not overrun under different control objectives while maintaining the system power factor. Finally, simulations and experiments verify the effectiveness of the control strategy.