PWM-VSI overmodulation technique with carrier harmonics reduction for auxiliary railway power supply

Auxiliary railway power supplies are needed onboard rolling stock to provide medium or low voltage to different systems from the catenary. In this kind of applications, the THD reduction of the filtered output voltage and a great regulation capability associated to the wide input catenary voltage range are the main goals to be reached. In order to achieve these objectives a novel overmodulation strategy for voltage-source inverters is presented. The new overmodulation technique has been tested and validated trough an auxiliary railway power supply prototype. Experimental results demonstrate the feasibility and the effectiveness of the proposed technique.