A standard multiple-unit train in China includes eight compartments, where compartments 1 to 4 constitute a first unit, and compartments 5 to 8 constitute a second unit. Two ends of the train are provided with two cabs, respectively. When the train travels, only one cab is activated, that is, the cab of the first unit is activated to control the train to travel, or the cab of the second unit is activated to control the train to travel.
For example, in a case that the cab of the first unit is used, the cab of the first unit controls the train to travel. The driver operates a pantograph, such that the pantograph rises up to contact with an overhead contact line, by which the train is powered.
For the multiple unit, in addition to supplying power to the train to draw the train to travel, the overhead contact line supplies power to auxiliary equipment in the train. The auxiliary equipment includes, for example, an auxiliary fan of a traction system, an air conditioner, an air compressor and other electric equipment.
However, in a case that a three-phase bus ground fault occurs when the train travels, an auxiliary power supply system fails. In this case, the train traction equipment, the air conditioner and the air compressor cannot operate normally, and the train is out of service.
Therefore, it is necessary for those skilled in the art to provide an auxiliary power supply device for a multiple-unit train, to facilitate normal power supply of the train.