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MODBUS is still one of the most widespread application layer protocols used in industrial communication due to its simple request-response communication session and its readiness to be implemented on top of several lower level communication protocols and various physical media such as RS232/RS485 serial lines and Ethernet TCP/IP. Given the well-known inclination of Modbus to inter-networking, a solution...
Since radio links in wireless body area networks (WBANs) commonly experience highly time-varying attenuation due to topology instability, communication protocols with fixed transmission power cannot produce a very good performance in terms of energy consumption, interference range, and communication reliability. We explain that how channel behaviourcan be modelled using Markov Chain. Then, a power-adaptive...
One of interesting problems, arising with deployment of large-scale systems, is integration of its nodes (systems / devices). In this work, we discus how to apply semantic technologies, as a mechanism to support node integration and facilitate interoperability within the developed ecosystem. We focus on pragmatic aspects of the proposed solution, discussed from the perspective of the Dependable Embedded...
Gallium Nitride (GaN) based power devices have been demonstrated to deliver higher energy efficiency than their Silicon (Si) counterparts for 200–1.2kV rated applications. The benefits of GaN technologies and their market potential will be highlighted in this paper together with the main challenges that GaN-based power systems need to overcome to reach their full potential and finally enter the market...
Recent advances and new trends in high voltage SiC based MOSFETs are analyzed. The main focus is done on design optimization strategies for reducing the on-state resistance. Gate oxide treatments for improving the interface quality resulting in a lower channel resistance are reviewed as well as solutions for lowering the JFET and bulk resistance components. The 3rd quadrant operation, short-circuit...
In this paper, the design and operation of two 650 V/ 60 A Gallium Nitride (GaN) devices in parallel is discussed in detail, further, the challenges faced and the trade-offs required for paralleling high speed GaN devices are also examined. The dynamic characterization of two devices in parallel is presented in detail. The phase leg design requires both power loops and gate loops to be as small and...
Targeting the development of a silicon carbide (SiC) inverter for electric vehicle/hybrid electric vehicle (EV/HEV) applications, the design considerations of the gate driver for the adopted SiC metal-oxide-semiconductor field-transistor (MOSFET) power modules are presented. Given the system power density requirement, the gate driver design challenges for the commercial off-the-shelf (COTS) SiC modules...
This paper presents a comparative study on high-frequency active rectifier-based zero voltage soft-switching (ZVS) resonant dc-dc power converters with Gallium Nitride Heterojunction-Field-Effect-Transistor (GaN-HFET) for inductive power transfer (IPT) systems. The two types of active rectifiers, i.e. high-frequency bridgeless rectifier (BLREC) and totem-pole rectifier (TPREC) are adopted for the...
Although the hybrid switch consisting of high power Si IGBT and low power SiC MOSFET achieves reduction of losses and cost, there is a severe concern of its short-circuit capability due to its internal SiC MOSFET with small die size. Experimental study shows that the short-circuit capability of hybrid switch is limited by that of SiC MOSFET. The physical mechanism of short-circuit capability of SiC...
While investigations on short-circuit ruggedness of discrete SiC MOSFET are widely encountered in the scientific literature, there is not so much research dealing with the operational robustness of high power SiC MOSFET modules. In this paper, the short-circuit (SC) ruggedness under hard switching fault (HSF) of a commercial 1.2 kV/180 A SiC MOSFET power module in half-bridge configuration will be...
Bi-directional switches, also called four quadrant switches (FQS), are the basic building blocks in many power converter circuits, such as cyclo-converters, matrix converters etc. Conventional approaches to realize bi-directional switch involves combination of unidirectional controllable blocking device (IGBT or MOSFET) and diode. In this approach, current flows through multiple devices for any direction...
The advancements in wide-band-gap (WBG) devices are enabling applications of power electronics converters coupled directly to medium voltage and incorporating galvanic insulation within the converter using high-frequency solid-state transformers. This paper presents the design and the characterization results of a SiC H-bridge converter suitable for up to 100 kVA single-phase ac-dc modular solid-state...
This paper describes the effect of MOSFET internal capacitances on the channel current during the turn-on switching transition: an intrinsic theoretical switching speed limit is found and detailed mathematically. The set of analytical equations is solved and the effect of the displacement currents is highlighted with ideal simulated waveforms. A laboratory experiment is thus performed, in order to...
Wide Band Gap power semiconductor switching devices offer superior performance compared to an equivalent Si power device. SiC MOSFETs can be competitive when compared to Si IGBTs of the same voltage class, whilst offering greater benefits at high switching frequencies. Operating SiC MOSFETs at high switching frequencies imposes significant challenges, including: Ringing and voltage overshoot issues,...
A capacitor voltage balancing method for a three phase modular multilevel DC-DC converter (MMDC) is proposed in the paper. The MMDC is derived from a three phase DAB and a modular multilevel converter (MMC) and inherits desirable features of both topologies. To guarantee stable operation of the MMDC, submodule (SM) capacitor voltages are required to be balanced. The proposed balancing method is to...
GaN-FETs are attractive switching devices for their fast switching capability. However, they often suffer from the oscillatory false triggering, i.e. a series of self-sustaining repetitive false triggering induced after a fast switching. The purpose of this paper is to derive a design instruction to prevent this phenomenon. According to the previous study, the oscillatory false triggering was found...
Z-source inverters (ZSIs), compared to the conventional two-stage architecture, embrace some interesting features, like the reduced size and complexity of the entire conversion system. Many research activities have been established to improve the performance of the so-called ZSI since it has been proposed in 2003, and several modifications have been introduced since then. These modifications include...
A method for in-situ high bandwidth junction temperature estimation of Insulated Gate Bipolar Transistors (IGBTs) is introduced. The method is based on the acquisition of the gate voltage plateau during turn-on, which can be directly related to the junction temperature. This allows fast over temperature protection of the power device and thus enables operation at the boundary of the device safe operation...
This paper presents a DC bus voltage balancing control method for the grid-connected hybrid cascaded converter with renewable energy sources. The proposed control method is based on the power flow management in the hybrid cascaded converter, which is investigated in this paper, and is thus capable of overcoming the unbalanced conditions arising at DC-side or AC-side. Laboratory test results under...
An edge-resonant soft-switching time-sharing (TS) multiple-input (MI) dc-dc converter is introduced in this paper. The proposed converter can achieve high efficiency with zero-current switching (ZCS) and zero-voltage switching (ZVS). The zero-current switching (ZCS) can be realized on switch turned-on states, and the zero-voltage switching (ZVS) can be realized on switch turned-off states. In addition,...
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