Isolated Asynchronous Generator Research Articles

A New and Simple Mathematical Technique to Study the Steady-state Performance of Isolated Asynchronous Generator

Isolated Asynchronous Generator (IAG) is nowadays widely used for renew-able power generation from the sources like wind and small hydro. Tradi-tionally, the steady-state analysis of IAG is carried out by solving a complexhigher order non-linear polynomial equation obtained in a complicated wayfrom the steady-state circuit diagram. In this paper, a simple new mathe-matical procedure has been introduced to obtain two non-linear polynomialequations in much more simplified form which can easily be solved forthe unknown variables i.e., per unit generated frequency (a) and magnetiz-ing reactance (Xm). Between these two equations, one equation comprisesonly one unknown variable‘a’ and hence, easy to solve. Differential SearchAlgorithm (DSA) has been efficiently implemented for solving these non-linear equations. The computational efficacy of DSA has been compared withthat of Newton-Raphson (N-R) method, Linear Search Algorithm (LSA),Binary Search Algorithm (BSA) and Particle Swarm Optimization (PSO) technique. The performance of the IAG has been studied under differentoperating conditions such as variation of speed, capacitance and load. Allthe simulated results have been experimentally verified using a three-phase,415 volts, 2.2 kW, star-connected induction generator and a close agreementhas been found.

Experimental and simulation testing of an EGLC controller for an IAG-EGLC system for electrifying off-grid rural sites

The voltage support at consumer terminals is required in remote areas. This voltage support should be provided economically. In the manuscript, the study carried out emphasis on the designing methodology and hardware implementation of an electronic generator load controller (EGLC) for an isolated asynchronous generator (IAG) feeding single-phase loads. The EGLC is build using the uncontrolled rectifier bridge, an IGBT based chopper switch with series connected dump load. The driving signals for the IGBT based chopper switch is generated using Pule Width Modulation PWM IC. The generator is providing power to the two loads connected in shunt across each other. The objective of the controller is to maintain constant load on the generator during the entire operation of the generator. The expected simulated outcomes are verified using a hardware model of the EGLC prototype developed for an IAG in the laboratory. The closeness of both the simulated and experimental results justified its application for the electrification of various off grid remote sites available in hilly areas.Article HighlightsAn EGLC Controller is designed, fabricated and tested in the laboratory for an IAG for voltage and frequency support.The proposed controller maintains constant load on the generator irrespective of nature of varying load.The prototype developed for an IAG-EGLC proves to be cost effective and can be proposed for electrification of off grid sites.

Asynchronous Generator With Battery Storage for Standalone Wind Energy Conversion System

This paper deals with the implementation of a voltage and frequency controller (VFC) for an isolated asynchronous generator (IAG)-based stand-alone wind energy conversion system (SWECS) with a battery energy storage system (BESS) feeding three-phase four-wire loads. The control algorithm for VFC is based on a low-pass filter (LPF) for estimation of reference source currents. The VFC is realized using a voltage source converter (VSC) with a BESS at its dc bus and a nonisolated T-connected transformer to feed three-phase four-wire consumer loads. Test results are presented to demonstrate the performance of a proposed VFC for an IAG in the wind power generation.

Stand-Alone Single-Phase Power Generation Employing a Three-Phase Isolated Asynchronous Generator

This paper deals with a stand-alone single-phase power generation using a three-phase isolated asynchronous generator (IAG) coupled with a wind turbine or a pico-hydro turbine. The proposed voltage and frequency controller (VFC) for a stand-alone single-phase power generation is used as a phase balancer for a three-phase IAG, a load leveler, and an active filter. The VFC is realized using a three-leg voltage-source converter and a battery energy storage system. The VFC ensures optimum utilization of a three-phase IAG for feeding a variety of single-phase loads, improves conversion efficiency, and reduces noise and vibration in the IAG. The rating considerations of an IAG and VFCs are also discussed for a single-phase power generation. The performance of an IAG system is demonstrated under steady-state and dynamic conditions of feeding single-phase linear and nonlinear loads. Simulated results are validated with test results on a developed system.

Neural Network Based Voltage and Frequency Controller for Isolated Wind Power Generation

This paper deals with an artificial neural network based control of the voltage and frequency (VF) of autonomous wind power generation using an isolated asynchronous generator (IAG) feeding three-phase four-wire loads. The reference generator currents are estimated using the adaptive linear neuron and its training through least mean square (LMS) algorithm to control the VF of an IAG system. Three-leg voltage source converter (VSC) with an isolated T-connected transformer is used as an integrated VSC. The integrated VSC with a battery energy storage system is used to control the active power of the wind energy conversion system (WECS). Bi-directional power flow capabilities of the proposed VF controller in WECS are demonstrated through simulation results. The proposed controller functions as a VF regulator, a load leveler, a load balancer and a harmonic eliminator in the WECS. The WECS is modeled and simulated in the MATLAB using the Simulink and the sim power system toolboxes.

Neural-Network-Based Integrated Electronic Load Controller for Isolated Asynchronous Generators in Small Hydro Generation

This paper deals with a neural-network (NN)-based integrated electronic load controller (IELC) for an isolated asynchronous generator (IAG) driven by a constant-power small hydro uncontrolled turbine feeding three-phase four-wire loads. The proposed IELC utilizes an NN based on the least mean-square algorithm known as adaptive linear element to extract the fundamental component of load currents to control the voltage and the frequency of an IAG with load balancing in an integrated manner. The IELC is realized using zigzag/three single-phase transformers and a six-leg insulated-gate bipolar-transistor-based current-controlled voltage-source converter, a chopper switch, and an auxiliary load on its dc bus. The proposed IELC, with the generating system, is modeled and simulated in MATLAB environment using Simulink and Simpower System toolboxes. The simulated results are validated with test results on a developed prototype to demonstrate the effectiveness of IELC for the control of an IAG feeding three-phase four-wire linear/nonlinear balanced/unbalanced loads with neutral-current compensation.

Voltage and frequency control of asynchronous generator for stand-alone wind power generation

A synchronous detection-based control algorithm for voltage and frequency control (VFC) of an isolated asynchronous generator (IAG) is proposed for a stand-alone wind energy conversion system (SWECS). A three-legged voltage source converter (VSC) with an isolated star/polygon transformer is used as an integrated VSC. The integrated VSC with a battery energy storage system is used to control the active and reactive powers of the SWECS. The SWECS is modelled and simulated in the MATLAB using the Simulink and the sim power system toolboxes. Test results on the developed prototype of SWECS are also presented to validate the control algorithm. The proposed VFC functions as a voltage and frequency regulator, a load leveller, a load balancer and a harmonics filter in the SWECS.

Voltage and Frequency Controllers for an Asynchronous Generator-Based Isolated Wind Energy Conversion System

This paper presents a state of art on voltage and frequency controllers (VFCs) for isolated asynchronous generators (IAGs) for standalone wind energy conversion systems. In wind turbine-driven IAG, magnitude and frequency of the generated voltage vary because of varying consumer loads and wide fluctuation in wind speeds. Therefore, new types of VF controllers based on a voltage source converter along with a battery energy storage system are proposed to maintain the voltage and frequency of IAG constant at varying wind speeds and varying consumer loads. A set of new VF controllers is designed and their performance is simulated in the MATLAB environment using Simulink and Sim-Power System toolboxes to study their behavior for standalone wind power generation.

VSC with a T-connected transformer-based electronic load controller for an isolated asynchronous generator feeding three-phase four-wire loads in a micro hydro system

This paper deals with a novel solid state controller (NSSC) for isolated asynchronous generator (IAG) feeding three-phase four-wire loads driven by constant power prime movers, such as uncontrolled micro hydro turbines. AC capacitor banks are used to meet the reactive power requirement of the asynchronous generator. The proposed NSSC is realised using a set of IGBTs (insulated gate bipolar junction transistors) based current controlled voltage source converter (CC-VSC) and a DC chopper at its DC bus, which keeps the generated voltage and frequency constant in spite of changes in consumer loads. The neutral point of the load is created using a T-configuration of the transformers. The IAG system is modelled in MATLAB along with Simulink and PSB (power system block set) toolboxes. The simulated results are presented to demonstrate the capability of isolated generating system consisting of NSSC and IAG driven by uncontrolled micro hydro turbine and feeding three-phase four-wire loads.

Electronic Load Controller for a Parallel Operated Isolated Asynchronous Generator Feeding Various Loads

This paper presents an investigation on a voltage and frequency controller (VFC), which functions as an improved elec-tronic load controller (IELC) for parallel operated isolated asynchronous generators (IAGs) in an autonomous hydro power generation system. In such type of hydro scheme whole generating system is isolated from the grid and supply electricity to the remote communities. The single point operation of these generators is realized, in such a manner that excitation capacitors, speeds, load, voltage, currents of generators remain constant under various operating conditions. The proposed controller consists of a 3-leg IGBT (Insulated Gate Bipolar Transistor) based voltage source converter (VSC) and a DC chopper with an auxiliary load at the DC bus of the VSC. The IELC controls the reactive and active powers simultaneously for controlling the voltage and frequency under varying consumer loads. Along with voltage and frequency control through single point operation of IAGs driven by uncontrolled pico hydro turbines, the IELC meets the power quality standard an IEEE-519 and it keeps the total harmonic distortion (THD) of the terminal voltage and currents within the limit of 5%. Here the proposed electrical system along with its controller is modeled in MATLAB along with Simulink and PSB (Power System Block-set) toolboxes. Simulation results are presented to demonstrate the capability of proposed controller for an isolated generating system.

Stand-Alone Wind Energy Conversion System with an Asynchronous Generator

This paper deals with a stand-alone wind energy conversion system (WECS) with an isolated asynchronous generator (IAG) and voltage and frequency (VF) control feeding three-phase four-wire loads. The reference generator currents are estimated using the instantaneous symmetrical component theory to control the voltage and frequency of an IAG system. A three-leg voltage source converter (VSC) with an isolated star/delta transformer is used as an integrated VSC. An integrated VSC with a battery energy storage system (BESS) is used to control the active and reactive powers of the WECS. The WECS is modeled and simulated in MATLAB using the Simulink and the Sim Power System (SPS) toolboxes. The proposed VF controller functions as a voltage and frequency regulator, a load leveler, a load balancer and a harmonic eliminator in the WECS. A comparison is made on the rating of the VSC with and without ac capacitors connected at the terminals of an IAG. Simulation and test results are presented to verify the control algorithm.

Decoupled Solid State Controller for Asynchronous Generator in Pico-hydro Power Generation

This paper deals with a decoupled solid state controller (DSSC) for an isolated asynchronous generator (IAG), used in constant power pico-hydro power generation for feeding three-phase four-wire loads. The proposed DSSC is used to control the voltage and frequency of the IAG in the decoupled manner. This DSSC is a combination of a voltage regulator (VR) for regulating the voltage and a conventional electronic load controller (ELC) for controlling the active power to regulate the frequency. The VR is realized using a zigzag/three-single-phase transformer and six-leg insulated gate bipolar transistors (IGBTs)-based current controlled voltage source converter (VSC) with a capacitor on its DC bus and an ELC is a combination of a three-phase diode bridge rectifier with a chopper switch and an auxiliary load. The proposed DSSC with an isolated generating system is modeled and simulated in MATLAB along with Simulink and power system blockset (PSB) toolboxes. The simulated results of the IAG-DSSC system are presented to demonstrate its performance for feeding three-phase four-wire linear/nonlinear (balanced/unbalanced) loads with the neutral current compensation.

Voltage source converter with a transformer as an electronic load controller for a stand-alone power generation

This paper presents a new configuration of a voltage and frequency controller for a stand alone pico hydro power generating system employing an Isolated Asynchronous Generator (IAG). The proposed controller is an Electronic Load Controller (ELC), which consists of a three leg IGBT (Insulated Gate Bipolar Junction Transistor) based Voltage Source Converter (VSC), a DC chopper and an auxiliary load at its DC bus. The neutral terminal for the consumer loads is created using a star delta transformer and the proposed system is modelled and simulated in MATLAB using Simulink and PSB toolboxes.

Design and Control of Voltage Regulators for a Standalone Power Generation

This paper presents various configurations of voltage source converter (VSC) based voltage regulators (VRs) for a stand alone power generation employing an isolated asynchronous generator (IAG). A set of VRs are designed and their performance is simulated using Simulink and Power System Blockset (PSB) toolboxes to demonstrate their capabilities as a voltage regulator, a harmonic eliminator, a load balancer and a neutral current compensator. It also discusses their merits and demerits, to select a suitable topology of the voltage regulator according to IAG system requirements.

A STATCOM based voltage regulator for parallel operated isolated asynchronous generators feeding three-phase four-wire loads

This paper presents an investigation on a voltage regulator for parallel operated isolated asynchronous generators (IAGs) supplying three-phase four-wire loads driven by constant speed prime mover like diesel engine, bio-mass, gasoline, etc. The proposed voltage regulator is realised using a static compensator (STATCOM) for providing the reactive power compensation, harmonic elimination and load balancing. Three single-phase insulated gate bipolar transistors (IGBTs) based VSCs along-with three single-phase transformers and self-supporting DC bus are used as a voltage controller for supplying three-phase four-wire loads. The neutral point of the load is achieved using the neutral point of the excitation capacitors and primary windings terminal of the transformers. The proposed isolated electrical generating system is modelled and simulated on MATLAB using Simulink and power system blockset (PSB) toolboxes. The performance of the proposed voltage controller for IAGs is demonstrated while feeding linear and non-linear balanced and unbalanced loads.

Independent voltage and frequency controller for a parallel operated isolated three‐phase asynchronous generators

AbstractThis paper presents a voltage and frequency controller (VFC) for parallel operated isolated asynchronous generators (IAGs) in pico and micro hydro systems feeding 3‐phase 4‐wire loads. The proposed VF controller regulates the system voltage and frequency in decoupled manner through control of reactive and active powers. The controller is a combination of a static compensator (STATCOM) and an electronic load controller (ELC). The STATCOM is used for reactive power compensation for voltage control, load balancing, harmonic elimination and neutral current compensation while an ELC is used for active power control at the terminals of the generators, which in turn keeps the system frequency constant. Modelling of the proposed generating system is carried out in MATLAB‐based environment and a set of simulation results are given to demonstrate the performance of the controller in an isolated electrical distribution system using SIMULINK and PSB (Power System Block sets) toolboxes. Copyright © 2008 John Wiley & Sons, Ltd.

Decoupled Voltage and Frequency Controller for Isolated Asynchronous Generators Feeding Three-Phase Four-Wire Loads

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper deals with a decoupled voltage and frequency controller (DVFC) for an isolated asynchronous generator (IAG), also known as the self-excited induction generator (SEIG), used in constant power applications such as pico hydro uncontrolled turbine driven IAG for feeding three-phase four-wire loads. The proposed controller is used to control the voltage and frequency at the generator terminal independently. The proposed decoupled controller is a combination of a STATic synchronous COMpensator (STATCOM) for regulating the voltage and an electronic load controller (ELC) for controlling the power which in turn maintains the system frequency constant. The STATCOM is realized using a 4-leg insulated gate bipolar transistor (IGBT)-based current controlled voltage-sourced converter (CC-VSC) and a self-supporting dc bus, while the ELC consists of a three-phase diode bridge rectifier, a chopper switch and an auxiliary load. The proposed generating system is modeled and simulated in MATLAB along with Simulink and power system blockset (PSB) toolboxes. The simulated results are presented to demonstrate the capability of an isolated generating system for feeding three-phase four-wire loads with the neutral current compensation. </para>

Neural network-based voltage regulator for an isolated asynchronous generator supplying three-phase four-wire loads

This paper deals with a neural network-based solid state voltage controller for an isolated asynchronous generator (IAG) driven by constant speed prime mover like diesel engine, bio-gas or gasoline engine and supplying three-phase four-wire loads. The proposed control scheme uses an indirect current control and a fast adaptive linear element (adaline) based neural network reference current extractor, which extracts the real positive sequence current component without any phase shift. The neutral current of the source is also compensated by using three single-phase bridge configuration of IGBT (insulated gate bipolar junction transistor) based voltage source converter (VSC) along-with single-phase transformer having self-supported dc bus. The proposed controller provides the functions as a voltage regulator, a harmonic eliminator, a neutral current compensator, and a load balancer. The proposed isolated electrical system with its controller is modeled and simulated in MATLAB along with Simulink and PSB (Power System Block set) toolboxes. The simulated results are presented to demonstrate the capability of an isolated asynchronous generating system driven by a constant speed prime mover for feeding three-phase four-wire loads.

A Novel Solid State Controller for Parallel Operated Isolated Asynchronous Generators in Pico Hydro Systems

This paper deals with a novel solid state controller (NSSC) for parallel operated isolated asynchronous generators (IAG) feeding 3-pbase 4-wire loads in constant power applications, such as uncontrolled pico hydro turbines. AC capacitor banks are used to meet the reactive power requirement of asynchronous generators. The proposed NSSC is realized using a set of IGBTs (Insulated gate bipolar junction transistors) based current controlled 4-leg voltage source converter (CC-VSC) and a DC chopper at its DC bus, which keeps the generated voltage and frequency constant in spite of changes in consumer loads. The complete system is modeled in MATLAB along with simulink and PSB (power system block set) toolboxes. The simulated results are presented to demonstrate the capability of isolated generating system consisting of NSSC and parallel operated asynchronous generators driven by uncontrolled pico hydro turbines and feeding 3-phase 4-wire loads.