A four-quadrant HEV drive system

A research project for a drive system for hybrid electric vehicles is described. The main target is to develop a system, which enables the combustion engine (ICE) to operate at optimal conditions, thus decreasing fuel consumption and emissions. The electrical system consists primarily of an electrical machine with two rotors and one stator, two converters and a battery. The concept enables the vehicle to be operated at different speed and torque independent of the engine´s operating point. The sizes of the electrical components are limited depending on the required variation in speed and torque. Simulations show a significant reduction of fuel consumption for vehicles in urban traffic. The concept, which is very compact, can be implemented with both radial and axial flux electrical machines. Several modes of operation are possible, such as hybrid mode, electrical mode, pure ICE driving, cranking and regenerative braking.