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Gallium-nitride is an emerging power semiconductor technology with considerable promise for applications requiring compact and efficient power conversion at competitive cost. In this paper gallium-nitride power electronic devices, circuits, and applications are reviewed and compared in terms of device specifications, circuit topologies, and cost.
High Voltage Direct Current (HVDC) short circuit protection is a fundamental requirement for any HVDC transmission system. Presently, all point-to-point links are protected using circuit breakers on the AC side of the converters. In order to enable HVDC grids, a more advanced protection system must be developed. HVDC circuit breakers are one solution for the protection of future HVDC grids. Several...
In this paper we present an optimization-based procedure for designing a reference circulating current which stabilizes the internal dynamics of a modular multilevel converter. This procedure relies on unconstrained convex optimization and it takes into account conflicting performance requirements such as reducing the oscillating components of circulating current and arm voltages. Tracking of such...
At present, most of the grid connected photovoltaic (PV) systems are operating at maximum power points and injecting power in uncontrolled way. Thus, active generator will be a good solution to support instantaneous power balance, frequency control and maintaining the power quality with controllable power injection. This new mode of active generator needs innovative power management. The new proposed...
This paper proposes a predictive control strategy for the voltage stability of a six-phase electrically excited starter generator for the aircraft DC power system. The starter generator is a synchronous machine coupled to the aircraft engine, and it is connected to 270V DC bus via a dual three-phase voltage source inverter that utilizes the DC output power. In the generation mode, the external excitation...
This paper presents a single-phase to three-phase adjustable-speed drive (ASD) system, which consists of a diode rectifier and a single-stage boost inverter without electrolytic capacitors (E-caps). The system has no shoot through issues and gains high reliability due to the shoot-through zero state regulation method. By using E-caps-less topology, the life time can be greatly increased. By properly...
This paper discusses an energy-efficient LED lighting distribution system in high-rise buildings based on 48Vdc bipolar ELVDC distribution nano-grid fed from a centralized AC/DC converter. The paper first introduces the LED lighting system performances and its associated challenges. It then introduces the preference for ELVDC distribution system in the built environment. The paper then presents the...
More electric aircraft (MEA) technology is achieved by exchanging various mechanical and pneumatic elements of a conventional aircraft with their equivalent electrical devices in order to increase the reliability and decrease the maintenance. This paper proposes a proportional resonant (PR) controller together with the adaptive space vector modulation (ASVM) technique for the more electric aircraft...
With the rapid development of hall electric propulsion, higher requirement for improving power and efficiency of power processing units was created. We introduce a kind of phase-shifted full-bridge soft switch technology, which is applied in anode-supply of hall electric propulsion. In the paper, the advantages of phase-shift full bridge converter in high voltage and high power anode-supply area are...
Voltage Stability Index (VSI) is a commonly used performance indicator for electrical distribution networks. A high value of VSI at each node implies an overall stable distribution network. A variety of methods are available in literature to determine VSI of a distribution network connected in radial configuration. However, very little has been done to determine VSI for loop-connected distribution...
This paper reports the design and implementation of a laboratory scale DC microgrid system that optimizes the overall fuel efficiency of multiple generators of possibly different performance characteristics through a combination of high efficiency custom-built AC/DC converters, integrated battery storage for load smoothing and a control system for the management of critical and non-critical loads.
Micro-grids (MG) are expected to be low inertia grids especially due to the deployment of power electronics used to connect distributed generation (DG) units. This issue brings consequences on the grid dynamics, reducing the frequency stability margins. To this end, the emulation of synchronous machines has been proposed as a possible alternative. This paper explores the benefits of this concept comparing...
The capability of islanding detection has become a requirement for grid connection of inverters utilized in distributed generation (DG) systems. The parallel RLC resonant circuit comprised, as a local load, in the standard test of islanding detection schemes offers lower impedance for higher frequency harmonics. With the presence of such a parallel RLC circuit, the full power balance between the distributed...
Load-shedding is a mechanism to prevent overloading of the autonomous microgrids (MG). To minimize loadshedding, extra support can be provided by the embedded floating batteries in the autonomous MG. Furthermore, two islanded neighboring MGs can be interconnected to support each other. For this, the state of charge (SOC) of the floating batteries should be above the minimum SOC and extra generation...
A low-cost and small size inverter module is required for a low-power motor system. In this work, we developed a compact GaN inverter module that is composed of GaN-GIT power devices and DBM (Drive-by-Microwave) gate drivers. The fabricated compact 5kW GaN inverter module successfully reduced its foot print for the gate drivers by 55% because it doesn't require an isolated DC power source. The fabricated...
A low frequency supercapacitor circulation technique coupled with a commercial low dropout regulators(LDO), namely the supercapacitor assisted LDO (SCALDO), can achieve significantly high end-to-end efficiency(ETEE) for linear regulators. The ETEE could be closer to the efficiencies of practical switching regulators, but without having the negative aspects of switching regulators such as RFI/EMI issues...
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