Patent ID: 7740092

Claim:
A system for powering a plug-in hybrid electric vehicle comprising a vehicle drivetrain having an internal combustion engine and one or more motor-generators connected to the drivetrain, wherein the one or more motor-generators supply power to the drivetrain to propel the vehicle or start the engine or absorb power to regeneratively recharge one or more energy storage devices; said system comprising a first electrical energy storage device; a second electrical energy storage device; and power electronics; wherein the first electrical energy storage is a battery that delivers electrical energy to the drivetrain for traction power or to start the engine, or absorbs electrical energy from the drivetrain; wherein the second electrical energy storage device is a flywheel, capacitor, ultracapacitor, supercapacitor, or battery; and the second electrical energy storage device only absorbs or delivers current as necessary to protect the first electrical energy storage device from current above a damage threshold for the first electrical energy storage device; and wherein the power electronics include a polyphase power converter with a plurality of phase legs, wherein each phase leg comprises two electronic switches with diodes; wherein both ends of each phase leg are connected to a DC bus; wherein a center of each phase leg is connected to another electrical device; wherein one or more capacitors are connected across the DC bus; wherein a first of said plurality of phase legs is used as a DC-DC converter for the second electrical energy storage device; and wherein one or more sets of three phase legs from the power converter function as one or more three phase motor drives.