Optimal Module Count for ISOP LLC Resonant Converters based on an HF Transformer Genetic Algorithm Optimization in Motorsport Applications

This paper investigates the selection of the optimal number of modules in an Input-Series-Output-Parallel (ISOP) LLC resonant DC-DC converter for motorsport applications. The study employs a Genetic Algorithm (GA) multi-objective optimization of the High Frequency Transformer (HFT) power losses and total volume. The analysis is repeated for converters with different numbers of modules, considering both commercially available and custom transformer cores, as well as air and water cooling systems. The Pareto front of solutions is determined and presented in each scenario. Optimization results indicate that for commercial cores, the range of optimal solutions is significantly constrained by thermal limitations. Conversely, a wider range of solutions can be obtained with custom cores. Furthermore, a lower number of modules is preferable for achieving high efficiency. On the other hand, increasing the number of modules can increase the converter power density, although this results in lower efficiency.