ABSTRACT. Recent studies in electro-aerodynamic (EAD) propulsion have stimulated the need for lightweight high-voltage medium-power converters. This paper demonstrates a design of a converter with a 200V dc input and a dc output up to 750W at 40kV, achieving a specific power of 1.5kW/kg. This is considerably lighter than comparable industrial and academic designs. The weight of the converter is minimized by modeling, comparing and selecting different designs of inverter, transformer and rectifier stages, then optimizing the voltage gain of each stage with considerations of device limitations and losses. A prototype is developed, experimented to drive an EAD-propulsion unmanned aerial vehicle.

ABSTRACT. This paper presents a design methodology for creating a miniaturized, affordable, and portable electrostatic precipitator (ESP) that can reduce the number of respiratory diseases in households suffering from indoor air pollution. We trace existing technologies and standards to combat indoor air pollution, and ultimately create an ESP that can withstand rural environments via a novel electrode design that allows precipitation at lower voltages, and two circuit topologies that offer a low and high power solution.

ABSTRACT. The efficiency of PV systems is significantly reduced
due to the accumulation of dust on the surface of the panels
in dry, desert regions. This study presents a brief survey
of existing automated panel-cleaning methods followed by the
implementation of a high voltage dielectrophoresis (DEP) based
cleaning system. Using a DEP approach allows for a low-cost,
power-efficient cleaning mechanism without the need for contact
with the panel surface. The design of a high step-up ratio power
electronics architecture is described along with several custom
etched electrode patterns. The sensitivity of this technique to
design parameters is also investigated by sweeping operating
voltage, frequency, and solar panel tilt and observing the effect
on dust removal. Using the most effective electrode pattern, the
designed system can remove 80% of the dust on the electrode
surface in under 20s. When operated with an air gap between
the electrode pattern and the dust, the system is capable of
restoring 10% of the panel’s short-circuit current once cleaning
is complete.

ABSTRACT. This paper presents a new DC/DC Buck converter architecture where parasitic inductance available in USB cable is utilized for energy storage element, targeted for mobile battery chargers. The proposed architecture enables heat spread along the cable, allows board size reduction and removes battery charger heat from the load system. A predictive control method is proposed to regulate output voltage without directly sensing. It is verified in simulations and experiments using a 10W smart-USB-cable charger. The converter is switched at 2 MHz for a conversion from 5V to 3.3V and achieves stable operation across a wide load range and load transients.

ABSTRACT. Online learning resources are gaining wider attention, especially as flipped-learning and massive open online courses are becoming more popular. Various types of lecture videos were developed for introductory control and power electronics courses implemented based on the flipped learning educational model. The approach and pedagogy is outlined for these flipped-learning courses and video lecture development. Feedback and responses from students is used to evaluate and discuss the effect of video quality on student learning and explore effective video qualities. Generally, self-made and professional videos both show similar learning effectiveness.

ABSTRACT. This paper proposes a new dc-dc modular multilevel converter (MMC) topology for MVDC and HVDC applications that does not require ac transformers or coupled inductors. The dc-dc MMC comprises two dc-dc subconverters that are interlinked in a symmetric manner, whereby the modulated ac voltages remain isolated from the dc terminals. This novel idea enables a substantial reduction in converter size, weight, capital cost and operating losses. The proposed dc-dc MMC has buck/boost capability and can block dc fault currents. A dynamic controller is developed based on a derived converter model. The converter operation and dynamic controls are validated by simulation.

ABSTRACT. In this paper, a novel multi-port multi-cell (MPMC) topology is proposed, which combines the features of two independent two-port converter systems, which are commonly used in state-of-the-art electric vehicles. Consequently, a higher overall power-density of the system results. The proposed converter comprises multiple identical sub-converters (cells), where each cell carries the same share of the total converter power. This multi-cell approach mitigates several technological design challenges arising in single-cell solutions, where extremely high output currents and high step-down ratios are required. Finally, a MPMC control strategy is introduced, which guarantees stable operation and balanced cell-powers in the converter.

ABSTRACT. We present a decentralized control strategy that yields switch interleaving among parallel connected buck converters without communication. Our method is based on the digital implementation of the dynamics of a nonlinear oscillator as the controller. Each controller is fully decentralized, i.e., it only requires the locally measured output current to synthesize the PWM carrier. By virtue of the intrinsic electrical coupling between converters, the nonlinear oscillator-based controllers converge to an interleaved state with uniform phase-spacing across PWM carriers. To the knowledge of the authors, this work represents the first fully decentralized strategy for switch interleaving of paralleled dc-dc buck converters.

ABSTRACT. This paper presents a modular approach to differential power processing. The method combines the series differential power processing approach with the parallel differential power processing approach to allow scalability that previously could not be achieved. The modular approach is demonstrated for photovoltaic systems, and it is shown possible to add groups of panels in series or parallel and still operate the differential power processing units to achieve maximum power point tracking.

ABSTRACT. Series stacking of dc voltage domains to allow power delivery at higher voltages and lower currents has been explored for some time. Differential power processing (DPP) is an integral part of many such applications. DPP benefits from bidirectional converters to process the difference in currents between two consecutive stacked domains to regulate voltages of each domain. In this paper we discuss the importance of having DPP converters with low light load power loss. Then we develop a multiphase buck/boost converter with asymmetric current sharing between phases to achieve good efficiencies over a wide load range. A new light-load (variable frequency, discontinuous conduction mode) control is also developed to improve light load efficiency.