Abstract: A power converter includes a protection circuit, a controller, and a power conversion circuit. The protection circuit includes a first positive temperature coefficient (PTC) resistor, a first switch unit, and a second switch unit. The power conversion circuit includes a direct current bus, and the direct current bus includes a positive direct current bus and a negative direct current bus. The first switch unit is connected between a power supply and an input end of the power conversion circuit or is connected in series on the direct current bus of the power conversion circuit. The first PTC resistor is connected in parallel to the first switch unit. The second switch unit is connected in parallel between a positive port and a negative port of the input end of the power conversion circuit or is connected in parallel between the positive direct current bus and the negative direct current bus.

Abstract: This application discloses a three-wire DC-DC converter and a parallel power supply system. The parallel power supply system includes a common wiring busbar, an input wiring busbar, an output wiring busbar, and at least two three-wire DC-DC converters. Each three-wire DC-DC converter includes a DC-DC conversion circuit, an input wiring terminal, an output wiring terminal, and a common wiring terminal. Input wiring terminals of all the three-wire DC-DC converters are connected in parallel to the input wiring busbar, output wiring terminals of all the three-wire DC-DC converters are connected in parallel to the output wiring busbar, and the common wiring terminals of all the three-wire DC-DC converters are connected in parallel to the common wiring busbar. The wiring busbar is configured to connect a first direct current power supply and a load.