Suboptimal Supervisory Level Power Flow Control of a Hybrid Electric Vehicle

This paper develops a supervisory level power flow suboptimal controller for a hybrid electric vehicle. The power flow model has two modes of operation determined by whether or not the electric motor is motoring or generating. The solution to the hybrid optimal control problem uses the recently developed embedding technique which places the original problem into a parameterized family of problems. The parameterized family of problems, amenable to the application of classical optimal control theory, is then solved. Because of the usual numerical difficulty in solving the state and adjoint equations simultaneously combined with nonlinearities in the model, a suboptimal piecewise solution is obtained for tracking a trapezoidal driving profile. Results are reasonable and encouraging.