Wide Voltage Range DC/DC Converter for Railway Auxiliary Power Units

Wide Voltage Range DC/DC Converter for Railway Auxiliary Power Units

This paper proposes, manufactures and tests a universal DC power converter that uses a wide range of input voltages making it suitable as a power unit for railway trucks, or as an independent power management unit for stand-alone photovoltaic solar power systems. Due to variations in international standards for railway power units the nominal input voltage of a practical DC-DC converter should allow for a variation of at least 30% ~ 40%. However, the nominal input voltage of DC-DC converters for railway applications can be anything between 24V ~ 110V. Therefore, several DC converters with different nominal input voltages are required for differing railway transportation vehicles. To reduce the circuit count, this type of device acts as a universal DC converter. The hybrid DC converter includes a boost circuit under low voltage conditions and a full-bridge circuit to facilitate management of a wide input voltage range of 16V~160V. The boost circuit and full-bridge circuits operate under low input voltages to increase voltage gain. Where input voltage is high, only the full-bridge converter operates to provide stability of output. To validate the practicality of the proposed circuit, this paper ran experiments using a 420 W prototype.