An example vehicle electrical power system includes a battery operable to power a load of a vehicle over a direct current (DC) bus, a multiphase alternating current (AC) machine comprising a plurality of windings, and a power converter. The power converter includes a plurality of power switches and a controller. The controller is configured to, in a first mode, operate the power converter as an active rectifier that provides current to the DC bus to supply DC loads, and charge the battery from the current on the DC bus; and in a second mode, operate the power converter as a boost converter that converts a variable output voltage of the battery to a constant voltage on the DC bus. The power converter utilizes the plurality of windings when operated as an active rectifier and boost converter. A method of operating a vehicle electrical power system is also disclosed.