The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper proposes a concept of two-terminal active capacitor implemented by power semiconductor switches and passive elements. The active capacitor has the same level of convenience as a passive one with two power terminals only. A control strategy that does not require any external feedback signal is proposed and a self-power scheme for gate drivers and the controller is applied to achieve the...
Multi-terminal dc (MTDC) grid has been considered as a promising future transmission and distribution system architecture, especially for remote renewable energy integration. However, short-circuit faults can be more detrimental to dc grids than ac grids. The lack of effective and economical dc circuit breakers and potential significant impact of dc fault on the connected ac system have become the...
With the improvement in the power electronic technologies, medium voltage dc (MVDC) electrical distribution systems are being considered for on-shore and off-shore applications. These future MVDC electrical distribution systems are expected to provide the possibility of easy interfacing of the renewable energy sources, improving the dynamics of the system and also help in reducing the carbon footprint...
A power-electronics-based DC-distribution system is a complex and extensively interconnected system consisting of multiple power converters. Consequently, a number of issues related to stability arise due to interactions among multiple converter subsystems. Recent studies have presented methods such as passivity-based stability criterion where the stability and other dynamic characteristics of an...
Microgrid research and development in the past decades have been one of the most popular topics. Similarly, the photovoltaic generation has been surging among renewable generation in the past few years, thanks to the availability, affordability, technology maturity of the PV panels and the PV inverter in the general market. Unfortunately, quite often, the PV installations are connected to weak grids...
The objective of this research is to analyze and evaluate the performance of the proposed shunt-series switched multi-functional grid-connected inverter (SSS-MFGCI) for mitigating unbalanced voltage sag and swell problem in distributed generation system or microgrid. Three quantitative performance evaluation factors, namely fault level factor, rating factor, and grid stiffness factor, are proposed...
Further growth in renewable energy integration would be dependent on reliability and cost-effectiveness. These two factors can be achieved through power converter topologies that enable transformer-less connection of renewable energy based technology to the grid. This paper presents a three phase five level dual tapped inductor quasi impedance source (qZS)-nested neutral point clamped (NNPC) topology...
Cascaded or distributed module-level inverters are becoming increasingly desirable for photovoltaic applications. The authors have demonstrated an AC-stacked topology that allows each inverter to operate completely autonomously from all the others. The only required communications is a low-bandwidth synchronization signal communicated from the point-of-grid-connection. This paper describes the communications...
Solid state transformers (SSTs) can be interconnected with each other through a distribution feeder to form a smart grid. When the main grid is disconnected, SSTs form an islanded microgrid. With available communications, master-slave microgrid control structure can be adopted. The system-level stability analysis can be simplified by considering only the grid interface stage of the SST. The loop feeder...
This paper presents the design process of a 13.56 MHz 10 kW and high efficiency inverter for wireless power transfer systems. The new 650V E-mode GaN is used in multiphase resonant topology to obtain high output power. The optimized efficiency design and the driver design are presented in detail. The circuit simulation results show that the inverter achieves 10 kW output power with the efficiency...
This paper introduces a closed-loop control architecture for an impedance control network (ICN) resonant dc-dc converter that regulates the converter's output voltage while achieving soft-switching across wide operating ranges. This architecture is based on enhanced phase-shift control of the ICN converter, in which the inverter and rectifier phase-shifts are simultaneously controlled to regulate...
A major drawback of the NPC inverter is an unequal power loss distribution among the power devices which leads to unequal temperature stress among them. Therefore, certain power devices experience higher temperature stress, which is the main cause of power device module failure and thus both the power rating and lifetime of the NPC inverter are limited by the most stressed devices. In this paper,...
The droop control technology, which can achieve an autonomous power sharing among distributed resources interface converters, provides the advantages of enhanced system reliability and reduced complexity. However, the reactive power sharing accuracy of the conventional Q — V droop method can be degraded due to its dependence on the line impedances. The Q — V droop control method was proposed to reduce...
A hybrid impedance model of Islanded MicroGrid with Paralleled Inverters Controlled by Droop and PQ Strategies (IMG-PICDPS) is derived, in which the PQ-controlled Inverters (PQ-Invs) are equivalent to Norton's circuits, while the DRoop-controlled Inverters (DR-Inv) to Thevenin's circuits in this paper. An impedance-based stability analysis method is further proposed according to the Nyquist criterion...
This paper is focused on the dynamic modelling of the polycrystalline silicon wafer-based photovoltaic cells under various operational and fault conditions. The models are drawn from the impedance changes observed using electrochemical impedance spectroscopy. In this paper, tests were carried out at different voltage bias levels under illumination, dark, uniform partial shading, and cell-mismatch...
A simplified shoot-through pulse width modulation (PWM) technique is presented for reducing switching losses in impedance source DC-DC converters. The proposed PWM method alternates shoot-through state conduction in each leg of the H-bridge, thereby increasing controllability of the converter, reducing the number of switching transients, and reducing the dynamic loss of the converter through soft-switching...
Lithium-ion batteries are at the forefront of energy storage technology due to its high energy density and durability; they are however expensive and must be operated within certain limits to prevent damaging them. Thus, there is a need for improved condition monitoring to increase its life expectancy and performance. In this work, Electrochemical Impedance spectroscopy (EIS) is implemented using...
Grid-tied Photovoltaic (PV) inverters are required to have harmonics mitigation control to reduce harmonics distortion on the output current caused by the impact of grid background harmonics. In this paper, a decentralized control strategy for reduction of the impact of distorted grid voltage on the AC-stacked PV inverter architecture is proposed. Two control schemes with the selective harmonics mitigation...
Recently, the medium frequency power electronic traction transformer (PETT) has received increased attention in the rail transit applications due to its small size, light weight, more space availability for passengers, multiple interfaces and other additional functionalities. However, the switching frequency is limited by the thermal tolerance of semiconductors which deteriorate as the switching frequency...
Conventional Hybrid Power Quality Conditioner (HPQC) adopts LC coupling branch and L coupling branch in the back-to-back converters to reduce the converter compensation capacity as well as the DC voltage. However, HPQC could only achieve the minimum compensation capacity under certain special load condition. To maintain the converter compensation capacity at a low level under all load conditions,...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.