METHOD FOR ELIMINATING SECOND HARMONICS OF DIRECT CURRENT BUS OF TRAIN

A method for eliminating second harmonics of a direct current bus of a train. The method comprises an active filtering device connected to the direct current bus, and specifically comprises a buck/boost bidirectional DC/DC converter (DC-APF), a filtering inductor (Ls), and an energy storage capacitor (Cs). According to a power balancing principle, when a secondary pulse of a bus voltage is fully compensated, a secondary pulse power output by a single-phase regulator needs to be controlled to have the same size as, and opposite polarity to, a secondary pulse power compensated by the active filtering device. The device utilizes a control system combining a current loop and a voltage loop, and performs closed-loop control according to actual electrical quantities detected by the system, such as a voltage and a current, thereby ensuring a compensation effect and a dynamic response capability of the system during actual operations of a train, improving system stability. The device replaces conventional passive LC