Bypass device failure detection device and method

The invention provides a bypass device failure detection device, which is characterized in that a first processor is connected with a second processor through an isolation module to obtain the output power, determined by the second processor, of a boost PFC (Power Factor Correction) converter; according to the obtained input current and input voltage of the primary side of a transformer in the boost PFC converter, the output power of the boost PFC converter, and the time period from the turn-on of the bypass device to the turn-off of the bypass device, the theoretical voltage value of the output capacitor in the boost PFC converter when the bypass device is turned off is determined; and whether the bypass device is in a failure state or not is judged according to a theoretical voltage value of an output capacitor in the boost PFC converter when the bypass device is closed and an actual voltage value of the output capacitor in the boost PFC converter when the bypass device is closed. The invention further prov