Multi-Objective Hierarchical Optimization: A Design Framework for Grid-Connected Interleaved H-Bridges

Abstract

The paralleling of power converters connected to the grid for power-sharing is a widely used technique. In this context, the design framework for a low-cost, lightweight, compact and high-performance optimum configuration is an open problem. This paper proposes an innovative Multi-Objective Hierarchical Optimization Design Framework (MO-HO-DF) for an AC grid interface with $N$ interleaved H-bridges, each with $M$ parallel “to-be-determined” switches, connected through coupling inductances ( $L_f$ ). A total of eight figures of merit (FOMs) were identified for the design framework optimization. A rigorous model of the power electronic system is presented. Next, a highly computationally efficient algorithm for the estimation of the required frequency modulation ratio ( $m_f$ ) to meet current harmonic performance requirements for any given configuration is proposed. Then, the concept and implementation of the algorithm are presented for the MO-HO-DF. The effectiveness of the design optimization framework is demonstrated by comparing it to a base case solution. Finally, the design calculations are validated via PLECS simulation with manufacturer-provided 3D power semiconductor models that include thermal modelling.