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The real-world performance of inverters is investigated across their full range of operation, concentrating on harmonic distortion and power factor. The inverters under review are representative of a cross-section of the UK market in terms of price and device quality. They include both voltage and current source converter topologies. The test results are compared against the relevant clauses of the...
Quality and quantity of the power being transmitted is an important datum to utilize the full potential of the existing transmission line networks. This paper presents a STATCOM having transformerless Cascaded Multilevel Inverter(CMI) with level shifted modified Space Vector Pulse Width Modulation(SVPWM) technique that provides both reactive power compensation and harmonic reduction. Synchronous Reference...
The huge, ever growing demand for electrical energy has hitherto been primarily met through the combustion of fossil fuels, and conversion of heat liberated therefrom. The relentless exploitation of these resources has raised questions regarding emission of green house gases, particulate pollution, and their harmful effects on environment. It also brings into focus the sustainability of generation...
In distribution network, with the installed of photovoltaic (PV), bought many problems. One of the most concerned problems is the overvoltage in the terminal bus of distribution network. It is caused by the reverse power flow which brought out by the increase of the PV sources penetration. In this paper, an improved PQ-Q (V) control strategy is proposed to alleviate such problem. The economic performance...
In the distributed generation systems, three-phase inverters are the basement because they are used as power electronics interface between the generators and the grid. Cascaded multi-level H-bridge inverters are widely used for industrial application due to the simple topology and good power quality. However, unbalanced power source problem will easily happen in such an application. In this paper,...
In this paper, a single-phase Seven-Level cascaded H-Bridge (CHB) based Shunt Active Power Filter (SHAPF) based on simple controller is proposed. Synchronous Reference Frame theory (SRF) is used for reference source current extraction and to generate gating pulses for the SHAPF. The main aim of the CHB is to eliminate harmonics, improve power factor and reactive power compensation of the single-phase...
Inverters in back to back (B2B) connection are utilized to convert the voltage and frequency of the power source to another format. Typical application of inverters is the wind power system. This study presents a B2B inverter for equal voltage and frequency format conversion in which one inverter works to get power from the grid to charge the DC capacitor and another inverter returns most of the active...
In this paper, proposed an adaptive droop controller using compensate for the mismatch in voltage drops across line impedance, to enhance reactive power sharing accuracy in island microgrid. Communication is used to facilitate the tuning of adaptive controller for the change of load. The method will ensure in accurate reactive power sharing even the communication is interrupted if the load does not...
Virtual oscillator control (VOC) and droop control are distinct methods to ensure synchronization and power sharing of parallel inverters in islanded systems. VOC is a control strategy where the dynamics of a nonlinear oscillator are used to derive control states to modulate the switch terminals of an inverter. Since VOC is a time-domain controller that reacts to instantaneous measurements with no...
Isolated grid-connected inverters are typically constructed of two stages, namely a voltage-source inverter stage and an isolated bidirectional dc-dc converter stage. Recently, two dual-bridge isolated series resonant dc-dc converters are used to synthesize segments of the line current and reconstruct the complete sinusoidal line currents using a three-phase unfolder. The unfolder technique synthesizes...
Droop-based control methods are used for operation of different inverters in the converter-interfaced AC microgrids. To ensure accurate power sharing among multiple inverters with fast dynamics and enhance stability in a stand-alone AC microgrid with constant impedance and constant power loads, this paper proposes a modified droop-based controller. The performance of the proposed controller is verified...
Due to the inherently distributed and heterogeneous nature of the microgrids, distributed control can be a promising approach to improving the stability, reliability and scalability of the microgrids compared with centralized control strategies. This work studies the distributed reactive power sharing problem for a microgrid with connected AC inverters. Under the lossless assumption of the microgrid,...
The traditional DG (distributed generation) wireless droop control base on “power-voltage-current” close loop is widely used. The power sharing performance of this method is significantly affected by the feeder impedance, mismatch inverter parameters, and unbalanced local load. Due to the affection of mismatched line impedance, the traditional droop method cannot make the reactive power shared accurately...
A nonlinear control strategy is developed for a single-stage single-phase grid-connected photovoltaic (PV) inverter in synchronous dq frame. The control scheme is proposed to achieve both maximum power point operation, regardless of the atmospheric conditions, and to control the active and reactive power. The control scheme forces the d-axis current to track a novel trajectory reference current, obtained...
In multi-infeed HVDC systems, AC faults at the terminal will likely lead to concurrent commutation failures of multiple HVDC converters, eventually causing the blocking of multiple HVDC system. Therefore, it is important to explore the interaction of voltages at different inverter side AC nodes and identify boundary conditions of concurrent commutation failure. The expression of the multi-infeed interaction...
The distribution static compensator (DSTATCOM) is the FACTS device used for regulate voltage in power distribution network. In this paper, the particular application of a DST-ATCOM in voltage control mode is investigated in a power distribution system. Simulated performance of DSTATCOM is presented at varying conditions. At the end, the result of simulation with Matlab Simulink software has been presented.
Reactive power compensation for solving voltage problem in PV farm based upon IEC 61850 is presented in this paper in order to control voltage within acceptable range. The Volt/VAR control is used in solar inverter of PV farm to improve power quality and also reduce the disconnection of solar inverter caused by overvoltage. So, the owner of PV farm will get more opportunity to sell solar electricity...
This proposed paper introduces the application of the inverter air conditioner by using the back to back converter to provide the reactive power during the steady state operation. This technique is used for improving the power factor of the smart home system or to provide the reactive power in the appropriate situation in both of constant reactive power supply and the maximum reactive power supply...
This paper proposes a mixed dq-control scheme for a sensorless PMSM drive to improve input power factor with an electrolytic capacitor-less bridge rectifier. Instead of using bulky traditional electrolytic capacitor, a very small film capacitor is adopted to achieve high input power factor with improved power density and reliability. However, due to large dc-link voltage fluctuations, deterioration...
This work presents the control design guidelines of a passivity-based control of the active and the reactive power in single-phase PV inverters. The control ensures global asymptotic convergence of the tracking error to zero and the PV inverter shows robust current tracking with fast dynamics. The control is particularized in the cases of strong and weak grid operation. In the last case, the knowledge...
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