Implementation of Multi-Modular Converter with Droop characteristics for High Speed Railway Traction System

Abstract

Multi Modular Converters (MMC) plays a significant role in high voltage power transmission networks due to its high scalability and modularity characteristics. MMC converters produce better efficiency & show superiority in harmonic performance in high voltage applications like HVDC and high speed AC-Traction power supply systems. Its bidirectional operation also aided to get high installation reliability comparatively. The complicated power quality problems such as voltage fluctuations, Harmonic issues and reactive power problems of railway tracks due to the rapid movement of the locomotives need to be mitigated. The loss of speed is caused due to the neutral sections (NS) which are present throughout the power line. It is necessary that the neutral sections should be eradicated especially for high speed railway networks. In this paper, a new traction power transmission network which comprises zero NS and comparatively low power quality problems is designed. Droop control strategy is implemented to improve power transfer capability between the two adjacent traction substations. The implementation of MMC with parallel converter concept using the DSP processor is executed for low voltage as a prototype model. The results obtained are confirmed that the proposed system is very much suitable for high speed railway networks. 

Index Terms: High speed traction, Parallel inverters, Droop characteristics, Indian traction power supply system.