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To ensure safe and reliable operation of power system based on wind energy, usually plant operators should satisfy grid code requirements such as grid stability, fault ride through (FRT), power quality improvement, grid synchronization and power control etc. To satisfy the grid code requirements of wind turbine, usually grid side converter is playing a major role. So in order to improve the operation...
Wind generation rapid development has brought challenge to the grid. Reactive voltage is the most outstanding and one of the most concerned problems. This paper introduces the concept of wind farms reactive power compensation and wind power grid code with respect to reactive power regulation all over the world, gives the simplified approach to estimate reactive power compensation capacity, and validates...
As the output power of the photovoltaic (PV) cell changes with the insolation , PV cell temperature and cell voltage changing. It is necessary to control the operating point to draw the maximum power of the PV cell in order to increase system efficiency. In this paper, two-level single phase PV grid-connected system is designed, which mainly includes PV cell, BOOST circuit, inverter, filter and the...
In this paper, a high gain single-stage buck-boost grid-connected system is proposed. The proposed system consists of a high voltage gain - high efficiency - switched inductor buck-boost converter (SIBBC) and a folded cascade H-bridge inverter. The proposed converter switch is derived with a sinusoidal modulation, so that the converter output voltage is a rectified sine wave which requires only a...
In an effort to utilize the solar energy effectively through power electronics converters (conditioners), a great deal of research is being carried out to meet the increasing demand for load. This paper proposes an experimental photovoltaic (PV) power conditioning system with line connection. The conditioner consists of a flying capacitors multi-cell inverter fed by a dc-dc boost converter. The boost...
Brushless Doubly-Fed Machine (BDFM) is a machine which incorporates the robustness of the squirrel cage induction machine while having the speed and power factor control of a synchronous machine. A special kind of rotor called Nested-Loop rotor plays an important part in the BDFM, coupling the two stator fields. In future BDFM will share a large part in wind power market. This paper presents a mathematical...
Doubly Fed Induction Generators (DFIG) has emerged as a suitable alternative for conversion of wind energy to grid quality energy under varying wind conditions. Often the control mechanism use large number of sensors and employ complex computations. Moreover, the reported control schemes for DFIG employing grid side converter (GSC) do not ensure a drawl of unity power factor (upf) sinusoidal current...
In this paper, a novel control algorithm has been proposed to regulate the DC bus voltage of a single phase shunt active power filter using a fuzzy logic controller. The DC bus voltage of a shunt active power filter should be controlled to compensate the filter losses on the grid. In many industrial applications, a PI controller is generally used to regulate the DC bus voltage of shunt active power...
Nowadays, most of the electrical railway tractions, especially the high-speed tractions are using AC-DC-AC power driving system. The best choice for the AC-DC link is four-quadrant PWM rectifier, which can provide controllable DC link voltage and better power factor for the grid. In high power drive applications, the switch frequency of the power semiconductor device cannot be very high, usually less...
This paper presents a method to minimize the losses and the magnetic cores volume in a single-phase active power filter based in a two stages grid-connected PV system. The proposed circuit injects PV generated power into the utility, and always acts as an active power filter to compensate load harmonics and reactive power such that the input power factor is very high independently of the solar radiation...
This paper deals with the analysis, modeling, and control of a doubly-fed induction generator (DFIG) driven by the wind turbine. A control technique is presented for extracting the maximum power from the wind turbine. The wind energy conversion system (WECS) is equipped with a DFIG and two back-to-back connected voltage source converters (VSCs) in the rotor circuit. The proposed control technique...
The paper presents a family of novel switched smart filter compensated devices using Green Plug Smart Filter Soft Starter GP-SF-SS devices for small single phase induction motors. GP-SF-SS devices are equipped with a dynamic online error driven optimally tuned controller that ensures improved power factor, reduced feeder losses, stabilized voltage, minimal current ripples and efficient energy utilization/conservation...
The paper presents a novel self adjusting wind energy utilization scheme using a modified single phase operation of the three phase induction generator supplemented by a voltage stabilization switched filter compensation scheme. The series-parallel switched capacitor filter scheme is controlled by a dynamic Particle Swarm Optimization PSO error driven self adjusting controller to ensure voltage stabilization,...
When it is in the wet season and the load is low, reactive power surplus and voltage rise are caused by high-efficiency power generation of small hydropower and load reduction in Linjiang region, Baishan city, JiLin province. These problems, which exist in the power grid, are systematically analyzed in this paper. The solution measures are proposed including generator in leading power factor on operation,...
In this paper, the principle of Static Var Compensator (SVC) is analyzed in detail, and a kind of SVC system which consists of Thyristor Controlled Reactors (TCR) and Fixed Capacitor (FC) is designed. Bridge rectifier and L-R circuit is used to simulate the symmetrical three-phase load. Based on instantaneous reactive power theory, the SVC system signals are detected rapidly and precisely. In order...
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 and can avoid some disturbances such as sags and swells. Most of STATCOM controllers are based on voltage controllers that are based on balance...
This paper investigates how different approaches to grid synchronization and reference frame orientation can improve the control performance of a voltage source inverter operating in a weak grid. It is first shown how voltage-sensor-less operation based on Virtual Flux allows for flexibility in how to choose the reference frame orientation of the control system. The different possible orientations...
In consequence of the generic irregularity of wave energy, it is difficult to envisage the performance of a grid connected wave energy converter without simulations. This paper details a study on directly driven, linear, permanent magnet generator based, wave energy extraction scheme provided with grid-connected three phase neutral point-clamped three level inverter. The linear permanent magnet generator...
This paper adopts a main circuit structure with back-to-back PWM converter, in which generator-side using direct torque control method, and grid-side adopts three-phase VSR inner current decoupling control based feed forward control algorithms, and this paper proposes an improved MPPT control methods, which can achieves more quickly and effectively tracking the maximum power. Finally, the effectiveness...
The change of active and reactive output of wind power station is quite random. If no appropriate reactive regulation is adopted, the voltage change of common connecting points will be frequently. After large-scale wind power station has been connected into the power grid, it will not only affect the power quality of the power grid but also endanger the safe and stable operation of the power grid...
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