Vector Control Realization of DFIG Under Grid Abnormalities using Real Time Digital Simulator

2016 ◽  
Vol 7 (4) ◽  
pp. 1337
Author(s):  
Kanungo Barada Mohanty ◽  
Satish Choudhury ◽  
Madhu Singh
Keyword(s):  
Vector Control ◽  
Real Time ◽  
Power Factor ◽  
Reactive Power ◽  
Low Voltage ◽  
Transient Behavior ◽  
Unity Power Factor ◽  
Voltage Swell ◽  
Real Time Digital Simulator ◽  
Grid Side

A grid connected doubly-fed induction generator (DFIG) system, driven by variable speed wind turbine is considered in this research to satisfy grid code requirements. Remaining grid synchronized and stable under voltage sag and voltage swell, obtaining power control through dc link voltage control, and providing unity power factor at grid terminals are the achievements. The DFIG system uses two back-to-back converters. Vector control strategy is used with the grid side and rotor side converters, and taken up for research for further improvement. The grid side converter controls dc-link voltage and maintains unity power factor at the grid connection point. The rotor side converter supplies the reactive power of the machine and maintains the speed constant irrespective of the transient behavior of the grid. In this paper the behavior of the DFIG system is analyzed under grid voltage fluctuation and the experimental results are obtained using RT-LAB. Main contribution of this work is in improving the DFIG system performance with grid low voltage and over voltage ride through capability through simulation, and its real time experimental verification.

Modeling and Execution the Control Strategy for the Three-Level Rectifier Based on Voltage Oriented Control

2017 ◽  
Vol 8 (4) ◽  
pp. 1603
Author(s):  
K. Y. Ahmed ◽  
N. Z. Yahaya ◽  
K. Ramani ◽  
V.S. Asirvadam
Keyword(s):  
Power Factor ◽  
Power Flow ◽  
Low Voltage ◽  
Switching Loss ◽  
Unity Power Factor ◽  
Excellent Performance ◽  
Load Variations ◽  
Sinusoidal Input ◽  
Grid Side ◽  
The Mathematical Model

In the recent years, three-level rectifier becomes an attractive rectifier replaced the two-level rectifiers. This rectifier provides many advantages, such as sinusoidal input current which contains low harmonics, unity power factor, bi-directional power flow, low voltage and switching loss for each switch. This paper presents a modelling and execution of the three-level rectifier for improvement of power quality under different loading based on voltage oriented control. The mathematical model and the control design were presented in this paper for the current inner loop and voltage outer loop, respectively. In order to evaluate the operation of the three-level rectifier under different conditions, the model was simulated by using MATLAB/Simulink. The experiment has been used to confirm the operation of the rectifier and its controller. The simulation and experimental results show that the excellent performance under steady-state and dynamic load variations was achieved; the unity power factor and pure sinusoidal in the grid side has also been accomplished.

scholarly journals Hybrid Reference Current Generation Theory for Solar Fed UPFC System

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1527
Author(s):  
R. Senthil Kumar ◽  
K. Mohana Sundaram ◽  
K. S. Tamilselvan
Keyword(s):  
Neural Network ◽  
Power Factor ◽  
Reactive Power ◽  
Voltage Source ◽  
Unity Power Factor ◽  
Current Generation ◽  
Load Voltage ◽  
Reference Current Generation ◽  
Source Current

The extensive usage of power electronic components creates harmonics in the voltage and current, because of which, the quality of delivered power gets affected. Therefore, it is essential to improve the quality of power, as we reveal in this paper. The problems of load voltage, source current, and power factors are mitigated by utilizing the unified power flow controller (UPFC), in which a combination of series and shunt converters are combined through a DC-link capacitor. To retain the link voltage and to maximize the delivered power, a PV module is introduced with a high gain converter, named the switched clamped diode boost (SCDB) converter, in which the grey wolf optimization (GWO) algorithm is instigated for tracking the maximum power. To retain the link-voltage of the capacitor, the artificial neural network (ANN) is implemented. A proper control of UPFC is highly essential, which is achieved by the reference current generation with the aid of a hybrid algorithm. A genetic algorithm, hybridized with the radial basis function neural network (RBFNN), is utilized for the generation of a switching sequence, and the generated pulse has been given to both the series and shunt converters through the PWM generator. Thus, the source current and load voltage harmonics are mitigated with reactive power compensation, which results in attaining a unity power factor. The projected methodology is simulated by MATLAB and it is perceived that the total harmonic distortion (THD) of 0.84% is attained, with almost a unity power factor, and this is validated with FPGA Spartan 6E hardware.

scholarly journals Modeling and Design of the Vector Control for a Three-Phase Single-Stage Grid-Connected PV System with LVRT Capability according to the Spanish Grid Code

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2899 ◽  
Author(s):  
Alexis B. Rey-Boué ◽  
N. F. Guerrero-Rodríguez ◽  
Johannes Stöckl ◽  
Thomas I. Strasser
Keyword(s):  
Vector Control ◽  
Reactive Power ◽  
Low Voltage ◽  
Single Stage ◽  
Photovoltaic System ◽  
Lookup Table ◽  
Voltage Sags ◽  
Pv System ◽  
Low Voltage Ride Through ◽  
Three Phase

This article deals with the vector control in dq axes of a three-phase grid-connected photovoltaic system with single-stage topology and low-voltage-ride-through capability. The photovoltaic generator is built using an array of several series-parallel Suntech PV modules and is modeled as a Lookup Table (two-dimensional; 2-D). The requirements adopted when grid voltage sags occur are based in both the IEC 61400-21 European normative and the allowed amount of reactive power to be delivered according to the Spanish grid code, which avoids the disconnection of the inverter under grid faults by a limitation in the magnitude of the three-phase output inverter currents. For this, the calculation of the positive- and negative-sequences of the grid voltages is made and a conventional three-phase Phase-Locked Loop is used for the inverter-grid synchronization, allowing the control of the active and reactive powers solely with the dq components of the inverter currents. A detailed enhanced flowchart of the control algorithm with low-voltage-ride-through capability is presented and several simulations and experiments using Matlab/SIMULINK and the Controller Hardware-in-the-Loop simulation technique, respectively, are run for several types of one- and three-phase voltage sags in order to validate its behavior.

scholarly journals Voltage Rise Regulation with a Grid Connected Solar Photovoltaic System

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7510
Author(s):  
Akinyemi Ayodeji Stephen ◽  
Kabeya Musasa ◽  
Innocent Ewean Davidson
Keyword(s):  
Power Quality ◽  
Power Factor ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Photovoltaic System ◽  
Voltage Amplitude ◽  
Phase Voltage ◽  
Unity Power Factor ◽  
Voltage Rise ◽  
Grid Current

Renewable Distributed Generation (RDG), when connected to a Distribution Network (DN), suffers from power quality issues because of the distorted currents drawn from the loads connected to the network over generation of active power injection at the Point of Common Coupling (PCC). This research paper presents the voltage rise regulation strategy at the PCC to enhance power quality and continuous operation of RDG, such as Photovoltaic Arrays (PVAs) connected to a DN. If the PCC voltage is not regulated, the penetration levels of the renewable energy integration to a DN will be limited or may be ultimately disconnected in the case of a voltage rise issue. The network is maintained in both unity power factor and voltage regulation mode, depending on the condition of the voltage fluctuation occurrences at the PCC. The research investigation shows that variation in the consumer’s loads (reduction) causes an increase in the power generated from the PVA, resulting in an increase in the grid current amplitude, reduction in the voltage of the feeder impedance and an increase in the phase voltage amplitude at the PCC. When the system is undergoing unity power factor mode, PCC voltage amplitude tends to rises with the loads. Its phase voltage amplitude rises above an acceptable range with no-loads which are not in agreement, as specified in the IEEE-1547 and Southern Africa grid code prerequisite. Incremental Conduction with Integral Regulator bases (IC + PI) are employed to access and regulate PVA generation, while the unwanted grid current distortions are attenuated from the network using an in-loop second order integral filtering circuit algorithm. Hence, the voltage rise at the PCC is mitigated through the generation of positive reactive power to the grid from the Distribution Static Compensator (DSTATCOM), thereby regulating the phase voltage. The simulation study is carried out in a MATLAB/Simulink environment for PVA performance.

scholarly journals A Four-Winding Inductive Filtering Transformer to Enhance Power Quality in a High-Voltage Distribution Network Supplying Nonlinear Loads

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 2021 ◽  
Author(s):  
Yuehui Chen ◽  
Zhao Huang ◽  
Zhenfeng Duan ◽  
Pengwu Fu ◽  
Guandong Zhou ◽  
...  
Keyword(s):  
Power Quality ◽  
High Voltage ◽  
Reactive Power ◽  
Low Voltage ◽  
Distribution Network ◽  
Nonlinear Loads ◽  
The Public ◽  
Passive Filters ◽  
Grid Side

This paper solves the problem of reactive power and harmonics compensation in a high-voltage (HV) distribution network supplying nonlinear loads. An inductive filtering (IF) approach where passive filters connect to the filtering winding of a four-winding inductive filtering transformer (FW-IFT) is presented to enhance the power quality of the public grid. This method can not only greatly suppress harmonic currents of the medium and/or low-voltage (LV) side, but also prevent them from flowing into the public grid. The new main circuit topology, where the FW-IFT has specific filtering winding by adopting the ampere-turn balance of the transformer, is presented. On the basis of the structure of the FW-IFT, the magnetic potential balanced equation and inductive filtering technology, its equivalent circuit and mathematical model are established, and the filtering performances are analyzed in detail. Simulation and experimental results rated at SN-10/0.38 of the FW-IFT are presented to prove the efficacy of the comprehensive enhancement of power quality on the grid side.

Effect of Distributed Generation on Voltage Levels in a Radial Distribution Network Without Communication

2009 ◽  
Author(s):  
Allie E. Auld ◽  
Jack Brouwer ◽  
Scott Samuelsen ◽  
Keyue M. Smedley
Keyword(s):  
Distributed Generation ◽  
Radial Distribution ◽  
Power Factor ◽  
Distribution System ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Load Drop ◽  
Unity Power Factor ◽  
Distribution Feeder ◽  
Circuit Power

The challenges associated with incorporating a large amount of distributed generation (DG), including fuel cells, into a radial distribution feeder are examined using a Matlab/Simulink™ model. Two generic distribution feeder models are used to investigate possible scenarios where voltage problems may occur. Modern inverter topologies make ancillary features, such as on-demand reactive power generation/consumption economical to include, which expands the design space across which DG can function in the distribution system. The simulation platform enables testing of the following local control goals: DG connected with unity power factor, DG and load connected with unity power factor, DG connected with local voltage regulation (LVR), and DG connected with real power curtailment. Both the LVR and curtailment strategies can regulate the voltage of the simplest circuit case, but the circuit utilizing a substation with load drop compensation has no universal solution. Even DG with a penetration level around 10% of rated circuit power can cause overvoltage problems with load drop compensation. This implies that some degree of communication will be needed to reliably install a large amount of DG on a distribution circuit.

scholarly journals Super-Twisting Sliding Mode Control for Gearless PMSG-Based Wind Turbine

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Mojtaba Nasiri ◽  
Saleh Mobayen ◽  
Quan Min Zhu
Keyword(s):  
Wind Turbine ◽  
Reactive Power ◽  
Low Voltage ◽  
Sliding Mode ◽  
Synchronous Generator ◽  
Voltage Regulation ◽  
Point Tracking ◽  
Chattering Free ◽  
Grid Codes ◽  
Grid Side

In recent years, the complexities of wind turbine control are raised while implementing grid codes in voltage sag conditions. In fact, wind turbines should stay connected to the grid and inject reactive power according to the new grid codes. Accordingly, this paper presents a new control algorithm based on super-twisting sliding mode for a gearless wind turbine by a permanent magnet synchronous generator (PMSG). The PMSG is connected to the grid via the back-to-back converter. In the proposed method, the machine side converter regulates the DC-link voltage. This strategy improves low-voltage ride through (LVRT) capability. In addition, the grid side inverter provides the maximum power point tracking (MPPT) control. It should be noted that the super-twisting sliding mode (STSM) control is implemented to effectively deal with nonlinear relationship between DC-link voltage and the input control signal. The main features of the designed controller are being chattering-free and its robustness against external disturbances such as grid fault conditions. Simulations are performed on the MATLAB/Simulink platform. This controller is compared with Proportional-Integral (PI) and the first-order sliding mode (FOSM) controllers to illustrate the DC-link voltage regulation capability in the normal and grid fault conditions. Then, to show the MPPT implementation of the proposed controller, wind speed is changed with time. The simulation results show designed STSM controller better performance and robustness under different conditions.

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