Beat‐less algorithm based on dual‐frequency compensation in railway traction applications

Abstract

The beat phenomenon can be a critical issue in railway traction applications. This paper proposes a dual-frequency compensation (DFC) method for the beat-less algorithm to shift the spectrum of the beat voltages to a higher-frequency region. Two variables for frequency compensation are derived by mathematical calculations based on the singlefrequency compensation (SFC) method. The applicability and superiority of the DFC method are analyzed. It is proposed that the DFC method can be a transition between the modulation index compensation (MIC) method and the SFC method, so the beat phenomenon can be greatly suppressed in the full speed range. The implementation of the DFC method is proposed to guide how to generate the two variables. The experimental verification is carried out on the StarSim hardware-in-loop platform, and the results demonstrate that the DFC method is more effective compared with the SFC method for beat phenomenon suppression. It also shows the modulation index with the DFC method is higher than that with the MIC method.