integrated power conversion systems and methods for use in an electric vehicle having an electric motor , a primary high - voltage energy source , and an auxiliary energy source including a traction inverter module operable for converting a dc current generated by the high - voltage energy source into an ac current capable of powering the electric motor , and a dc / dc converter operable to step - down a voltage of the high - voltage energy source or step - up a voltage of the auxiliary energy source , wherein the traction inverter module and the dc / dc converter may share one or more common components , such as a common high - voltage dc bus capacitor , a common dc bus bar , and / or a common high - voltage transistor .