Harmonic control method for multiple driving cycles of EMU based on improved C-type filter

Abstract

For traction substation (TS), the harmonic current spectrum distribution of the left and right power supply sections has a large difference under different EMU operating conditions. This phenomenon will further affect the harmonic distribution of the entire traction power supply system and has the risk of harmonic distortion. At the same time, it may also cause interference to the communication line. In this paper, the transient direct current control technology is used to realize the converter of EMU, and then the TS side harmonic model under regenerative braking condition is realized. The harmonic problem, control process, and negative sequence problem caused by locomotive traction braking on the TS side under various working conditions are analyzed in detail. After connecting the C-type filter to the traction network side of the system, the THD (total harmonic distortion) is within the standard range, while the negative sequence problem of the system has worsened. Therefore, the parameters of the filter were optimized to improve both harmonics and negative sequence problems by combining the negative sequence characteristics under various operating conditions. The results show that the improved treatment can effectively control the harmonic problem.