Hotel Load Converters for Indian Railways

Indian Railways aims to achieve 100% electrification transitioning from diesel generators (DGs) in end on generation (EOG) systems to hotel load converters (HLCs) in head on generation (HOG) systems to power hotel loads (HLs) on trains. AC-AC power converters are needed to convert 960 Vrms 1ph voltage from the traction transformer in locomotives to 750 Vrms phase-to-phase 3ph voltage to supply the local step-down transformers in respective coaches for these HLs. This paper presents the design and test results of 500 kVA Cummins-developed HLCs for HOG rail application. Firstly, key performance and safety specifications of the HLC are discussed. Next, major steps to design, test, and integrate the AC-DC rectifier and DC-AC inverter using 3.3 kV IGBT are presented. Finally, simulation and experimental results of pantograph bounce, IGBT DESAT, short-circuit, current THD, and phase-to-earth-feeder voltage limit are presented. The measured AC-AC efficiency was 96.35% at rated voltages and load.