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This paper proposes an adaptive power management strategy with reduced sensor requirement for grid connected hybrid microgrid system under faulty conditions which occur in grid tied converters. Generally parallel combination of grid tied converters (GTCs) are used as an interface between microgrid and grid, which are responsible for power transfer among renewable energy sources (RES), hybrid energy...
Energy generation via Photovoltaic (PV) technologies has increased in the last years. Large scale PV generation have attracted interest among countries due to low operation cost and wide PV resource disposition. However, some operative challenges in large scale PV plants had been detected: power imbalance, low power quality in terms of total harmonic distortion (THD), power factor and conversion efficiency,...
In Solar Photovoltaic (PV) generation, an increasingly important issue is the reliability of electronics such as inverters, and how efficiently (and reliably) they interact with the local grid. Total Harmonic Distortion (THD) is increasingly important, relating as it does to efficiency and localised heating. PV is intermittent, so to design controlled experiments to evaluate power quality inverter...
This paper describes the structure, control and performance analysis of an alternative configuration of a low cost three-phase transformerless online UPS. The proposed UPS avoids the use of galvanic isolation and consists of a half-bridge rectifier, a battery bank, a half-bridge inverter, a split DC bus and an auxiliary circuit. The auxiliary circuit is composed of an inductor and a small rating switching...
This paper reports on the work of the CIGRÉ C6.22 Working Group, Microgrid Evolution Roadmap, which has recently finalized its first Technical Brochure. The Working Group was asked to identify the main elements required to justify, develop, and implement viable microgrids, which the Group defined as follows: Microgrids are electricity distribution systems containing loads and distributed energy resources,...
Transition toward smart distribution networks with high penetration of photovoltaics (PVs) will involve incidental generation curtailment as an alternative to grid reinforcements. Microinverters are taking over popularity of string inverters in residential and some commercial areas mainly due to increased energy harvest. This paper demonstrates how microinverters with a modified overvoltage protection...
The purpose of this paper is to relate the issues which have an impact on the interconnection of distributed resources to the utility grid. Impact that can be clearly seen is with respect to the types of distributed resources and the power electronic (PE) devices used to interface them. A balance has to be maintained between the type of DER's and the interfaces in order to get the maximum benefit...
This paper discusses the need for power quality microgrids to provide 1/4 cycle response to compete with existing power quality products by offering similar performance. However, providing 1/4 cycle response in distributed line-interactive microgrids is difficult due to the challenge of force commutating the static switch. Seamless islanding adds significant cost to microgrids, and to avoid adding...
This paper proposes a flexible D-STATCOM (Distribution Static COMpensator) and its new controller system, that be able to both mitigate all types of faults and operate as a Distributed Generation (DG), when it supplies power to sensitive loads while the main utility source is disconnected (i.e. it is under islanded operating condition). Thus D-STATCOM operates same as a flexible DG (FDG) and consequently,...
Distributed resources are finding increased penetration in developing countries like India. The increased acceptance of such resources is mainly due to their modularity, increased reliability, good power quality and environment friendly operation. These are currently being interfaced to the existing systems using voltage source inverters (VSC's). The control of such distributed resources is significantly...
A major intention of the “More Electric Aircraft” concept (MEA) [1], is the use of power electronics instead of mechanical, hydraulical or pneumatical systems, which promises reduced weight, higher efficiency and less maintenance costs. This paper presents the design of rectifier topologies Active Power Factor Correction (APFC) and Autotransformer Rectifier Unit (ATRU) dedicated for a 46 kW electrical...
The penetration of distributed generation is increasing to assist main power plants worldwide. An efficient strategy of grid control integration, to interconnect the DG systems to conventional power systems, is required to improve the power quality and reliability (PQR). The main task of the interconnected system is to control and maintain frequency and voltage of the power system in an acceptable...
In mission critical power installations, such as data centres, the use of double conversion UPS has been considered the best choice to date for protecting against power quality problems. Indeed, this UPS technology allows for a high level of load protection against any type of electrical disturbance of the network and isolation of the mains against the load's non linear behavior. The cost saving related...
This paper presents a comparison study between the operation of a back-to-back and a matrix converter induction motor drive under the presence of faults in the power switches of these converters. These two topologies are functionally equivalent in terms of input power quality and energy regeneration capabilities but need to be compared in terms of performance under faulty conditions as well due to...
Distributed power generation will be formed in many weak distribution networks, after renewable energy sources are connected to them. It is very important to increase the reliability and efficiency of using these renewable energy sources. By using DVR (dynamic voltage restorer), the power quality problem in distributed power generation (e.g. voltage fluctuation) can effectively be solved. In this...
An increasing demand on the quality of wind power systems affects also more and more the fields of lifetime and reliability. But, problems like bearing damages because of bearing currents counteract these desired demands. Especially doubly fed induction generators, which are wide spread in use for wind turbines up to the MW-class can be limited in reliability because of the mentioned problem. Hereby,...
This paper compares the calculated reliability of a matrix converter with a controlled rectifier/inverter topology for an aerospace motor drive application. These topologies are functionally equivalent in terms of input power quality and regenerative capabilities. The military handbook MIL-HDBK-217F guidelines have been used to predict reliability. Although the matrix converter has a higher number...
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