Power supply system and abnormality determination method for precharge device in power supply system

An abnormality determination method for a bi-directional DC/DC converter in a power supply system including a first battery, a power control device that includes a first inverter, a second inverter, a step-up/step-down converter, a capacitor and that is connected to the first battery, and the bi-directional DC/DC converter configured to precharge the capacitor of the power control device in response to a system start-up request, the abnormality determination method comprising:

• transmitting a target voltage of the capacitor to the bi-directional DC/DC converter in response to the system start-up request;
• determining whether an abnormality has occurred in a communication state with the bi-directional DC/DC converter;
• wherein, when the abnormality of the communication state is not determined it is determined that the abnormality has not occurred, then determining whether the precharge of the capacitor is completed based on a detected value voltage from a predetermined voltage sensor configured to detect a voltage of the capacitor;
• when the precharge is completed,
• determining that the bi-directional DC/DC converter is normal when the precharge is completed;
• and
• determining that an abnormality has occurred in the bi-directional DC/DC converter when the precharge is not completed, wherein
• the precharge is determined as being completed when the detected voltage from the voltage sensor remains equal to or greater than a predetermined voltage for at least a predetermined time period.