HIGH EFFICIENCY HIGH DENSITY GAN BASED 6.6KW BI-DIRECTIONAL ON-BOARD CHARGER FOR PEVS
Executive Summary: In the 4th quarter of 2014, a program was formally initiated at Delta Products to develop and commercialize a lightweight, compact and high efficiency bi-directional on-board Charger (OBC) for plug-in electric vehicle use. The project was funded in part by the U.S. Department of Energy (DOE), under award DE- EE0006834. Delta products was the prime contractor to DOE during the three-year duration of the project. In addition to Delta Products, several additional supplier-partners were engaged in this research and development (R&D) program, including Transphorm, Inc., The Center for Power Electronics Systems (CPES) at Virginia Tech, and Fiat Chrysler Automobiles. The OBC uses novel control schemes enabled by Gallium Nitride (GaN) switches to obtain charger efficiency of 95% and reduce volume and mass by 50% of the existing state-of-the-art silicon (Si) based chargers and inverters. A Si-based bidirectional OBC is typically implemented with two separate modules: a charger and an inverter. A GaN-based bidirectional OBC can integrate both functions into a single module. It will result in substantial reductions in size, weight and cost. This enables the introduction of WBG devices in automotive production programs. The inverter function integrated with PHEV can act as emergency power source in case of power interruption. This increases the power security when the electric infrastructure is damaged by extreme weather conditions. This report summarizes the program and describes the key research outcomes of the program. A technical history of the project activities is provided, which describes the key steps taken in the research and the findings made at successive stages in the multi-stage work. The evolution of OBC prototypes is described in detail. After the program history is reviewed, the key attributes of the resulting OBC are described in terms of functionality, performance, and cost. The results clearly demonstrate the ability of this OBC to meet or exceed DOE's targets for this program, including: • Construction of a working product-intent prototype of a bi-directional on-board Charger (OBC); • Peak efficiency of 95% and volume reduction of 50% compared to a recent production modules of similar ratings. • Bi-directional operation at 120Vac and 240Vac in vehicle. In addition to meeting all the program goals, the program was completed within the original budget and timeline established at the time of the award. The summary program budget and timeline, comparing plan versus actual values, is provided for reference, along with several supporting explanatory notes. Technical information relating to the product design and test results are contained in the appendices to this report.