Vehicle-mounted power conversion system with power free allocation function

The invention provides a vehicle-mounted power conversion system with a power free allocation function, which relates to the field of power supplies and comprises a vehicle-mounted charger, two high-voltage batteries, two voltage reduction DC/DC converters correspondingly connected in parallel and two sets of low-voltage power supply paths formed by two corresponding low-voltage DC outputs. And the controller outputs switch control signals for controlling switch tubes in the first step-down DC/DC converter, the second step-down DC/DC converter, the first secondary side switch unit and the second secondary side switch unit to work, so that at least one of the first high-voltage battery and the second high-voltage battery serves as a power supply of at least one of the first low-voltage direct current and the second low-voltage direct current. Under the condition that no device needs to be added, the flexible configuration of the energy of the whole vehicle is realized on the basis of ensuring the redundant fun