Thermo-electric multiphysics topology optimization using finite volume method

Size and weight are two critical factors in the design of automotive inverters. Bus bars form essential components of the inverter assembly and significantly contribute to the overall weight of the assembly. Hence, optimization of the shape of the bus bar is crucial for an optimal unit. The optimal shape should require minimum material without compromising the functional requirements of low-temperature rise in the bus bar assembly. In the present work, we have developed a multiphysics simulation-based topology optimization (TO) algorithm that addresses the thermal trade-offs in the design process. We have used a density-based topology optimization method for optimal material distribution for the DC bus bar. The cell-centered finite volume method (FVM) has been used to discretize the strongly coupled governing equations. The sensitivity is derived for the finite volume global matrix, and the adjoint sensitivity method is used to determine the Lagrange multipliers. The method of moving asymptotes (MMA) is used for the optimization. These algorithms have been implemented in a C++ program. Numerical results are presented for a few sample test cases, which demonstrate the effectiveness of the finite volume-based topology optimization software for bus bar design.