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Full-Text Articles in Engineering

Lawn Buddy, Jayson Johnston, Andrew Brown, Jacob Maljian Jun 2020

Lawn Buddy, Jayson Johnston, Andrew Brown, Jacob Maljian

Electrical Engineering

Grass lawns are a common hallmark of the American home. In 2019, a survey from the National Association of Landscape Professionals found that 81% of all Americans owned a lawn [1]. Mowing is a time consuming and costly chore that is part of maintaining a grass lawn. The manual labor in mowing a lawn can exceed 40 hours per year [2]. People commonly incur weekly costs on mowing services to save time. Traditional gas powered mowers are physically demanding and use engines that need routine maintenance. They operate loudly enough that users should be wearing hearing protection and the noise …


Study Of A Symmetrical Llc Dual-Active Bridge Resonant Converter Topology For Battery Storage Systems, John K. George May 2020

Study Of A Symmetrical Llc Dual-Active Bridge Resonant Converter Topology For Battery Storage Systems, John K. George

Graduate Theses and Dissertations

A symmetrical LLC resonant converter topology with a fixed-frequency quasi-triple phase-shift modulation method is proposed for battery-powered electric traction systems with extensions to other battery storage systems. Operation of the converter with these methods yields two unique transfer characteristics and is dependent on the switching frequency. The converter exhibits several desirable features: 1) load-independent buck-boost voltage conversion when operated at the low-impedance resonant frequency, allowing for dc-link voltage regulation, zero-voltage switching across a wide load range, and intrinsic load transient resilience; 2) power flow control when operated outside the low-impedance resonance for integrated battery charging; 3) and simple operational mode …