Electric drive subsystem for a low-storage requirement hybrid electric vehicle

Integrating an electric machine drive system into the powertrain of a hybrid electric vehicle (HEV) represents a challenging exercise in packaging complex electromechanical and power electronic subsystems. The Ford combined alternator starter (FCAS) and its attendant power and control electronics are physically partitioned because power electronics has not yet evolved to the stage in which fully packaged drives can be realized. A similar situation exists for the control and sensor subsystems necessary for a fully functional high-performance drive. Hardware partitioning requires that more attention be given to installation issues and to mitigating system interactions. The FCAS system consists of an integrated starter/alternator (S/A), an S/A module (SAM), and a vehicle electrical infrastructure that can support the power and energy levels demanded. Our field experience with the FCAS system is presented along with test results obtained from vehicle operation.