Physics meets AI: trading accuracy for speed

In power electronics design, achieving high accuracy in numerical predictions often comes at the cost of significant computational time, slowing iterative processes such as magnetics' design.

We developed a machine learning-based model that integrates highly accurate data from numerical simulations with the speed of AI. Using tree-based models, as opposed to neural networks, our approach learns the underlying physics of foil winding losses, enabling rapid and precise predictions across a wide range of operational conditions and design features, and including the presence of an air gap. This solution significantly reduces computation time while maintaining high accuracy, enhancing the iterative design process in power electronics, and offering a practical and efficient alternative to traditional methods.

Introduction

If computational methods for physical modeling were fast, we would be all set: numerical predictions (e.g., Finite Element Analysis (FEA or FEM)) would hit high accuracy in a practical timeframe. But they are slow, and alternatives are needed. Especially for an iterative process like magnetic design. Traditional modeling approaches in power electronics have significant limitations: (i) numerical methods like FEM offer high accuracy but are slow, (ii) analytical methods are accurate and help understanding but are often limited to specific cases and are usually hard to develop, and (iii) empirical methods, while simple, are limited in scope and not versatile when aiming for generalization. Machine learning, on the other hand, is fast and improves when fed with more and more data.

This publication aims to leverage the best of both worlds, i.e., ML and numerical approaches, on the example of foil winding losses, a big challenge in power electronics design, especially in highfrequency applications. There are few analytical models for foil winding losses, and these are often restricted to scenarios without an air gap [1][2] or where the foil has the height of the core window height [3]. Even though these are typical cases, in many situations, finite element modeling (FEM) remains the only viable option. We invest time in generating highly accurate data through numerical simulations. Then an ML model learns the underlying physics and is now enabled to make highly accurate predictions much quicker. Like this, rapid and accurate predictions are achieved, improving the iterative design process. Our novel work uses those well-established machine learning models to solve the problem of foil losses in magnetics with the presence of an air gap.

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