The Concept of AC-Chopper Controlled Impedance for Railway Unbalance Compensation to Improve the Quality of Energy

Abstract

This paper investigates improving the quality of the energy used in the railway field. Due to structural aspects, the railway substations of the high-speed lines generate a voltage imbalance, polluting the electric power. To solve this unbalance problem, a new structure of unbalance compensation based on the concept of impedance controller by Ac-chopper was introduced. This new strategy's dimensioning and control were based on real data provided by the Moroccan national railway operator ONCF. To prove that this solution has a significant impact on the treatment of the unbalance phenomenon and that the CCI compensator behaves like an Eco-design due to its constitution and the reduction of power losses, a comparison was established with the topologies using a Voltage Source Inverter (VSI) and Current Source Inverter (CSI) in terms of energy loss in the semi-conductors; the modelling of the three structures was performed under the MATLAB Simulink environment. The results showed that the CCI compensator is more efficient in limiting the unbalance problem than the other compensators (VSI and CSI).