An Improved Integrated Grid Inductor-Transformer Magnetic Structure for Single-Stage EV Charger

This article introduced a magnetic integration method for the single-stage electrolytic-capacitorless onboard charger by merging the grid inductors and the high-frequency transformer. The feasibility of this integration relied on the fact that the applied voltage and frequency of these two components are the same. Separate magnetic cores are combined to form a 4-leg one-body core. The integrated magnetic structure considerably reduces the core volume, loss, and the number of components, therefore, a higher efficiency, power density, and lower production cost can be obtained. The performance of the integration technique is demonstrated by the implementation of a 3.7kW prototype with the output voltage range of 400-800V. The experiment shows an achievement of 96.9% peak efficiency.