In modern residential and commercial buildings today, electrical loads are growing fast to be more native direct-current (DC) loads, including computers, smartphones, cameras, smart-home devices, LED lightbulbs, information screens, televisions, microwave oven, and other appliances, etc. To optimize efficiency and maintain the reliability of the electric grid, DC sources and energy buffers, such as solar energy and other renewable energy sources, vehicle batteries, and other separate batteries are integrated at an unprecedented rate. While these electrical components are direct-current (DC) in nature, they still need to interface with the legacy alternating-current (AC) power line in our home and building, leading to inefficiencies in power delivery (10%-30% loss in total power consumption), space utilization, and added 10%-15% overall system cost for many AC-DC adapters. In addition, AC distribution at 110-220 volts in commercial buildings and households also poses a safety concern especially for children as AC wall outlets and cords are responsible for 15% and 63% of injuries, respectively, in children aged 12 years and younger. The goal of this integrated research and education career development is to facilitate faster developments and increase adoption of DC micro-/nano-grids for more efficient DC distribution in residential and commercial use in a More-DC world, by realizing a next-generation integrated hybrid DC-DC power converter family with demonstrations for multiple important applications. The converters are designed to achieve superior efficiencies, smaller sizes, and lower system cost that can reduce the number and impact of inefficient AC-DC conversions. The research program, positioned at the boundary of integrated circuits and power electronics, aims at fundamental advancements in converter technologies, integrated circuit designs, integrated packaging, and system integration for DC power management and delivery, applicable in billions of home and office devices. The research outcomes can be applied and create positive impacts in improving efficiency and density of power management and delivery in many applications, including mobile battery chargers, mobile computing, data centers, DChomes/DC-buildings, automotive vehicles, motor drive, and LED lightings. A significant part of the research program is to integrate fundamental research with education in the area of integrated power electronics and energy efficiency through training and involvement of US San Diego graduate and undergraduate students, specific outreach modules that will engage and attract K-12 students and the general public to this important STEM area, and teaching activities that integrate research topics and findings in the curriculum.

To achieve the research goal, the objectives of this CAREER proposal are to: (1) investigate and implement scalable integrated converters with high input voltage and large conversion ratio based on a novel single-inductor multi-synchronous stage (SIMS) DC-DC converter architecture that can efficiently provide large conversion ratios from high input voltages in order to minimize the number and impact of AC-DC conversions, (2) study and design integrated packaging procedures using integrated silicon capacitors to fundamentally reduce distribution loss and improve the system efficiency and power density, (3) generalize the median-average analysis (MAA) methodology, and use it to provide more accurate, intuitive model and control of hybrid DC-DC converters in order to bridge key knowledge gaps in understanding core operations and control of hybrid converters, (4) demonstrate and evaluate the feasibility of a DC nano-grid using a single AC/DC converter to supply multiple DC loads through the integrated converter prototypes developed in this project, and (5) demonstrate the integrated power delivery systems in a number of example applications, including battery charger, mobile and highperformance computing, and DC-home/DC-building power distribution. This comprehensive effort enables important innovations and fundamental advances to push the boundary of two areas, integrated circuits (with high input voltages, high power and current density) and power electronics (with large direct step-down, and integrated hybrid architecture).

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

National Science Foundation (NSF)
Division of Electrical, Communications and Cyber Systems (ECCS)
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Lawrence Goldberg
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University of California San Diego
La Jolla
United States
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