Power converter and boost unit failure detection method thereof

The invention provides a power converter and a boost unit failure detection method thereof, and the method comprises the steps: firstly detecting the input voltage of each boost unit, and detecting the voltage of a DC bus, and recording the voltage as a bus voltage; then controlling a post-stage conversion circuit to operate in different states, and respectively adjusting the voltage of the direct-current bus to be lower than each input voltage and higher than the bus voltage; when the voltage of the direct-current bus is lower than each input voltage, open circuit judgment is carried out based on the forward conduction characteristic of a diode in a bridge arm branch between input and output of the boosting unit, and for the boosting unit of which the input current is detected, it is determined that no open circuit occurs in the bridge arm branch between input and output of the boosting unit; and when the voltage of the direct-current bus is higher than the bus voltage, performing short-circuit judgment base