Active Power Filter‐Based Low‐Frequency Ripple Power Suppression of the DC‐Link in Railway Traction Systems

In this article, a novel active power filtering (APF) control method is proposed to suppress ripple power in the DC‐link of railway traction systems, including both the inherent second‐order ripple of single‐phase rectifiers and additional frequency ripples introduced by the pantograph–catenary arc. First, according to the transmission process of ripple power in the traction system, a ripple power decoupling model is established. Then, the model predictive control (MPC) scheme of the APF circuit with low switching frequency is introduced to primarily suppress the second‐order ripple voltage. Furthermore, to enhance steady‐state performance, these residual ripple voltages on the DC‐link are suppressed by compensating the capacitor current reference. Finally, experimental results demonstrate that the proposed control method has higher steady‐state accuracy and faster dynamic response compared to the traditional control method at low switching frequency, making it suitable for railway traction systems.