Discharge control apparatus arranged in power conversion system

A discharge control apparatus included in a power conversion system that comprises a DC power source outputting DC power;

• power conversion circuit provided with a series-connected switching element including a high-side switching element and a low-side switching element for converting the DC power into a predetermined type of power to be used by an electric device;
• a capacitor connected between the DC power source and the power conversion circuit;
• a switching circuit adapted to switch a conduction path between the DC power source and, the power conversion circuit and the capacitor, to be opened or closed;
• and first monitoring means for monitoring a state of the switching elements and outputting a signal concerning the state of the switching elements while the power conversion circuit is converting the DC power into the predetermined power, the discharge control apparatus comprising:
• discharge control means for controlling a charging voltage of the capacitor to be less than or equal to a predetermined voltage such that when the conduction path is opened by the switching circuit, both of the high-side switching element and the low-side switching element are operated to be turned on whereby both electrodes of the capacitor are short-circuit to discharge the capacitor;
• second monitoring means for monitoring the state of the switching elements and outputting the signal concerning the state of the switching elements, while the switching elements are operated in the same way as the discharge control means operates the switching elements;
• diagnostic means for diagnosing the switching elements and the discharge control means whether or not a fault occurs in the switching elements and the discharge control means based on the signals outputted by the first and second monitoring means;
• and
• transmitting means for transmitting the signals outputted from the first monitoring means and the second monitoring means to the diagnostic means, the first and second monitoring means and the diagnostic means being electrically isolated by the transmitting means.