A Passivity-Based Control of Euler–Lagrange Model for Suppressing Voltage Low-Frequency Oscillation in High-Speed Railway

The traction network voltage low-frequency oscillation (LFO) in high-speed railways easily leads to the traction blockade of electric multiple units (EMUs), which seriously affects the normal operation of high-speed railways. A passivity-based control (PBC) strategy for single-phase EMUs rectifier is proposed in this paper. First, for the single-phase EMU rectifier, the Euler-Lagrange (EL) mathematical model in dq frame is built, which can realize the decoupling of active power and reactive power. Second, according to the unique characteristics of the rectifier, it is proven that the rectifier is strictly passive, which is the premise of PBC controller design. Third, using the deduced EL mathematical model and the passivity of rectifier, the PBC controller for the single-phase rectifier of EMUs is designed using the damping injecting method. Next, compared with dq current control and interconnection and damping assignment PBC (IDA-PBC), it can be verified that the PBC controller has better dynamic and static characteristics, and can significantly suppress the voltage LFO of traction network. In these strategies listed in this paper, using the PBC, the single-phase rectifier input current has minimal total harmonic distortion, and the dc-link voltage has minimal oscillation. Finally, the dSPACE semiphysical experiment platform of the cascade system of EMUs and traction network is built. Simulation results are validated by the dSPACE semiphysical experiments, which indicate that the PBC has the better inhibitory effect for LFO as compared with that of the IDA-PBC and dq current control in single-phase EMUs rectifier.