| This thesis presents an optimal power sharing control scheme for hybrid power systems consisting of a constant voltage DC bus fed by multiple power sources through switch-mode converters. An optimal control design methodology is introduced. Using this methodology, a generalized optimal control scheme is developed. This control scheme is modeled and applied to the specific application of a fuel cell car. A cost-minimization technique is used where costs are assigned to the operation of the individual power sources as a function of the sources' output powers, and mathematical programming techniques are used to minimize the total of these costs. The cost-minimization technique sets up a nonlinear programming problem with a smooth convex objective function, nonnegativity constraints, and a single linear less-than-or-equal-to constraint. This is solved iteratively as a quadratic programming problem using a modified simplex method. |
