Electronics systems that can deliver high power density and efficiency becomes paramount. Through the development of innovative converter topologies, advanced control schemes, and optimization techniques, this project aims to elevate the performance of power converters, ultimately enhancing the charging experience for EV owners. By providing faster and more efficient charging solutions, the project supports the widespread adoption of electric vehicles, contributing to a greener and more sustainable future.

The implications of this project extend beyond the EV industry; it also plays a crucial role in promoting sustainable energy practices and reducing carbon emissions. Efficient power electronics systems lead to less energy loss during power conversion, thereby conserving valuable resources and reducing the burden on the electrical grid.

The power electronic structure under investigation consists of a power factor correction (PFC) converter and a DC/DC stage, both of which are essential components for achieving efficient power conversion. A PFC converter ensures that the power factor of the load is close to unity, minimizing power losses, reducing the burden on the power grid, and improving overall efficiency. The DC/DC stage provides a stable output voltage, accommodating the specific charging requirements of different EVs. To optimize these power converters and identify the best switching frequency, magnetic and thermal designs, the project focuses on developing accurate component models. These models include differential mode (DM) and common mode (CM) noise estimation, magnetics design, thermal design, and FET loss models. Understanding and optimizing these parameters are crucial for maximizing power density and efficiency, leading to more compact and cost-effective charging systems. Furthermore, the project investigates EMI filters, which play a vital role in suppressing electromagnetic noise and maintaining compliance with regulatory standards. By analyzing mutual and self-parasitic effects, the researchers have discovered that strategic arrangement of filter component placements can lead to a 20dB increase in noise attenuation, thus enhancing the performance of the overall system.

The project's research on the PFC stage has two primary objectives. The first is to optimize multi-level converters using low-voltage GaN FETs and increase input ripple frequency through phase-shifted multi-level structures. The second is to invent a soft-switching totem-pole (TP) PFC converter with interleaving legs. These innovations, combined with the optimization of the LLC converter and the development of experimental prototypes, demonstrate significant advancements in power electronics technology. The project's experimental prototypes have demonstrated impressive power density and efficiency results, highlighting the effectiveness of the developed models and optimization techniques. For instance, the two-phase interleaved soft-switched TP PFC converter achieved 62W/in³ and 98.72% efficiency at full load, while the 4-level TP PFC reached 67W/in³ and 99.2% efficiency. The optimized LLC prototype also showed promising results, with a power density of 45W/in³ and a peak efficiency of 98.2%.

These achievements have laid the groundwork for extending the developed models to very high-frequency designs. New converter configurations, such as the two-phase interleaved 7-level TP PFC and 3-phase LLC converters, have been analyzed, both utilizing planar magnetics. These high-frequency designs have the potential to further increase power density and efficiency, paving the way for even more compact and advanced power electronics systems. In particular, the 3-phase LLC design with planar magnetics employs an innovative approach known as asymmetrical interleaving. This technique integrates the resonant inductance into the transformer, enabling highly miniaturized designs. All the necessary analyses on the inductors have been conducted, and proof-of-concept prototypes are being manufactured. 

The 7-Level interleaved GaN-based TP PFC can deliver 3700 watts of power in a compact 250 x 68 x 20 mm form factor using planar magnetics, achieving a power density of 180 W/in³, which significantly exceeds the target of 85 W/in³. With an efficiency greater than 98.7%, this PFC stands out as more compact than any other industrial PFC currently available. When combined with an innovative three-phase LLC with integrated magnetics, the total power density of the system reaches 90 W/in³, fitting into a 1U x 1.5U x 6U space suitable for server applications. The overall efficiency exceeds 96%, meeting the requirements for the prestigious titanium efficiency grade. Overall, the project has been accomplished successfully exceeding the innovations expected before conducting the research.

The advancements made in this project not only demonstrate the potential for more efficient and compact power electronics systems but also showcase how cutting-edge research can push the boundaries of traditional power converter designs. By incorporating these high-frequency designs and innovative interleaving techniques, the project continues to make strides towards revolutionizing the power electronics landscape and enabling the widespread adoption of electric vehicles.