Penalty and Barrier-Based Numerical Optimization for Efficiency and Power Density of Interleaved Buck/Boost Converter

To achieve the global optimization of efficiency and power density of interleaved buck/boost converter (IBBC) for transportation electrification, a numerical optimization method is proposed based on the penalty and barrier theory. In this method, converter volume is the optimization objective, and efficiency and flux density are the constraints. To formulate the optimization objective and constraints, comprehensive modeling for IBBC is conducted, which decouples master-slave relationships among variables in the modeling process. Then, the penalty and barrier theory is performed on the optimization objective and constraints and an integrated optimization function is established, thus converting the constrained numerical optimization problem to an unconstrained one. Hereafter, a modified backtracking search method is employed for the minimization of the integrated optimization function, and Pareto fronts of efficiency and volume are obtained. Finally, a 60-kW IBBC converter was constructed and the power density reaches 9.65 kW/L, whereas the highest efficiency is 98.6%. Compared with an unoptimized converter, efficiency and power density are improved by 0.3% and 0.65 kW/L, respectively.