A Reusable Control System Architecture for Hybrid Powertrains

System integration is the path to successful entry of hybrid electric vehicle (HEV) technology into the marketplace. A modular solution capable of meeting varying customer requirements is needed. The controller must possess a flexible hierarchical architecture that insures cross-platform compatibility and provides adaptability for various engine, motor, transmission, and battery configurations. A hybrid powertrain supervisory controller (PSC) has been designed for an advanced parallel-type HEV prototype, which uses a continuously variable transmission (CVT). The controller schedules torque commands for the engine and motor and chooses the transmission ratio to meet driver demanded acceleration. The controller is organized around a state machine, which determines how best to employ powertrain components to satisfy the driver while maximizing fuel economy. The engine is shutdown under conditions such as idle or low speeds, where it would operate inefficiently and the motor is used instead to move the vehicle. The controller also selects the appropriate conditions under which the engine should recharge the battery. The algorithms the controller uses to manage torque and energy have general functionality to serve cross-platform needs. This paper will provide an overview of the PSC architecture and gives examples of its use in hybrid vehicle development.