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A DC-link voltage compensation method for a photovoltaic (PV) generation system with energy storage system(ESS) is presented. When PV power is oscillated, the DC-link voltage is also influenced. And this fluctuation of DC-link critically affects the load voltage when the ESS is operated in stand alone mode. In conventional method, huge capacitor bank is necessary to reduce the fluctuation. In this...
The ever mounting demand of electrical energy and the keen scarcity of conventional energy sources leads to the burgeon of distributed generation (DG) system. The main abstruse is the harmonization of the DG to the utility grid. Generally current regulated PWM voltage-source inverters (VSI) are used for synchronizing the utility grid with DG source in order to meet the following objectives: 1) To...
A reliable islanding detection method is one of the most important function of a well designed inverter based distributed generation (DG) system. Active islanding detection methods have negligible non-detection zone, but they bring some power quality issues to the network. In this paper an islanding detection method which addresses constant current inverter based DGs is introduced. It has both high...
This paper deals with the problem of the design of an all-digital implementation of a three-phase PLL and the control logic of a shunt active filter implemented with a Multilevel Current Source Inverter (MCSI). The active filter is connected to the medium voltage level of a power distribution system where compensation of reactive power and harmonics is mandatory. The PLL is essential to obtain a reference...
The increase use of renewable dc or battery as a source has further emphasized the importance in efficient design of inverter. This paper discusses a study to determine optimum operating parameters of a commonly used pwm unipolar inverter. Variations on the input voltage level and switching frequency will be investigated to see their impacts on the operation of the inverter as well as harmonics produced...
Static Compensator (STATCOM) has been widely proposed for power quality and network stability improvement. It is easily connected in parallel to the electric network and has many advantages for electrical grids. It can improve network stability; power factor, power transfer rating. It can also avoid disturbances such as voltage sag (dip) and swell which is the main concern of this paper. This paper...
This paper introduces a new cost effective structure of a 4-switch single-phase to three-phase converter using a Quasi Z-source (QZs) network for induction motor drive applications. In comparison to the traditional 6-switch structure, the proposed circuit reduces the cost of the system, switching losses and the complexity of the control method as well as the interface circuits used to make the trigger...
Power quality problems such as variation of reactive power consumption and distorted current injection in distributed generation system can be compensated by a single-phase conditioner. The proposed conditioner works in feed forward mode and placed in parallel with the PV-inverters in the distributed generation system. A simple current extraction method is applied and an operating algorithm of the...
Electricity in remote communities is usually provided by diesel power plants at relatively high costs. This issue can be addressed with the addition of renewable energy sources such as wind and PV. However, due to the intermittent and fluctuating characteristics of the power produced by these sources, the dispatch of the diesel gensets for operation with variable (droop-based) frequency, high efficiency...
The dynamic voltage restorer, with its excellent dynamic capabilities, when installed between the supply and a critical load feeder, can compensate for voltage sag/swells, restoring line voltage to its nominal value within few milliseconds and hence avoiding any power disruption to the load. A new topology based on Z-source inverter is presented in order to enhance the voltage restoration property...
Distributed generation (DG), such as solar-energy-based photovoltaic (PV) systems, wind generation, and other renewable resources, is a quickly growing source of energy for today's power system. These assets pose challenges to grid reliability and power quality. One critical challenge is islanding (inadvertent system separation) detection, separation, and eventual resynchronizing. Research is underway...
This paper presents a cascaded H-bridge multilevel inverter that can be implemented using symmetrical topology. A multilevel inverter is a power electronic device built to synthesize a desired AC voltage from several levels of DC voltages. Multi level inverters have been an important development in recent years. Owning the capability to increase the power quality delivered to the load for high performance...
This paper presents the modeling and simulation of a dynamic voltage restorer as a voltage sag/swell mitigation device in electrical power distribution networks. The dynamic voltage restorer, with its excellent dynamic capabilities, when installed between the supply and a critical load feeder, can compensate for voltage sags/swells, restoring line voltage to its nominal value within few milliseconds...
One of the major problems in electric power quality is the harmonic contents. This paper focuses on elimination (reduction) of harmonics in a H-bridge multi-level voltage-source inverter. Here the basic concept is to eliminate specific harmonics with a proper choice of switching angles. This technique is very efficient for improving the multi-level inverter output voltage quality. In This paper, Generalized...
This paper describes the performance analysis of a multi-functional grid-connected photovoltaic (PV) system using power hardware-in-the-loop simulation (PHILS). An intelligent control scheme for the multi-functional grid-connected PV power generation system is proposed and verified though the power hardware-in-the-loop simulation computer simulation and the digital signal processor TMS320F2812 controller...
This paper present three-phase four-wire active filter for power line conditioning (PLC) to improve power quality in the distribution network. The active power filter (APF) is implemented with PWM based current controlled voltage source inverter (VSI). This VSI switching signals are generated through proposed three-level hysteresis current controller (HCC) that achieves significant reduction in the...
Proliferation of the voltage-sensitive loads in the distribution systems has made the voltage quality an important issue. The main factors considering the voltage quality are the voltage sags and voltage swells. There are many available solutions to improve voltage quality. In the past years, application of the power-electronic based devices known as custom power devices have developed an interesting...
Recently, distributed generators are applied not only to inject power into the grid/local load, but also to compensate power quality problems. In this paper, a method for selective voltage harmonics compensation in microgrid based on the proper control of distributed generator (DG) interface converter is proposed. In this method, active and reactive power control loops are considered to control the...
This paper attempts to analyze the inherent harmonics present in Sine-PWM inverter output with battery as well as rectified AC as sources. A novel technique for reducing harmonics in PWM inverter output by modifying the reference waveform is proposed, which is validated by MATLAB simulations.
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...
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