Abstarct: In this thesis an evolutionary algorithm is employed to address the controller design problem baxsed on μ analysis. Conventional solutions to μ synthesis problem such as D-K iteration method often lead to high order, impractical controllers. In the proposed approach μ synthesis problem is solved as a constraint optimization problem in which robust stability and robust performance baxsed on μ analysis are considered and the cost function respectively. In order to solve the optimization problem an improved particle swarm optimization(PSO) is chosen to find the required coefficients of a structure-specified controller. The goal is to achieve a more practical controller with lower order. The performance and robustness of the proposed controller are investigated in a buck-boost converter in comparison with the D-K iteration controller (the conventional solution to μ synthesis problem). This thesis proposes the structured singular value(μ) approach to the problem of designing an output voltage regulator for a buck-boost converter with current-mode control. This technique proposes a novel alternative solution for solving the μ synthesis problem to design simple structure controllers satisfying robust stability and performance. Simulation results demonstrate the advantages of the proposed controller in terms of simple structure and robustness against plant perturbations and disturbances in comparison with D-K iteration controller.