Excited Induction Generator Research Articles

Optimization algorithms for steady state analysis of self excited induction generator

The current publication is directed to evaluate the steady state performance of three-phase self-excited induction generator (SEIG) utilizing particle swarm optimization (PSO), grey wolf optimization (GWO), wale optimization algorithm (WOA), genetic algorithm (GA), and three MATLAB optimization functions (<em><span lang="EN-US">fminimax</span></em><span lang="EN-US">, </span><em><span lang="EN-US">fmincon</span></em><span lang="EN-US">, </span><em><span lang="EN-US">fminunc</span></em><span lang="EN-US">). The behavior of the output voltage and frequency under a vast range of variation in the load, rotational speed and excitation capacitance is examined for each optimizer. A comparison made shows that the most accurate results are obtained with GA followed by GWO. Consequently, GA optimizer can be categorized as the best choice to analyze the generator under various conditions.</span>

MULTIFUNCTIONAL GRID CONNECTED INVERTER BY WIND ENERGY CONVERSION SYSTEM

Non-conventional mode of generation of electricity has several advantages over conventional sources of generation. It is eco-friendly, cost effective, damage free, long lasting and more over harmless. Electricity generation through wind energy is considered as socially beneficial and economically feasible for several applications. Domestic and industrial devices use more and more circuits having a non- linear behaviour. They create non-sinusoidal currents causing high harmonic currents in the distribution networks. In the proposed method, a three-phase multifunctional grid-connected inverter interfaced with a wind energy conversion system (WECS) is introduced. This system consists of a permanent magnet synchronous generator (PMSG) based wind turbine, a rectifier and a three-phase voltage source inverter connected to the utility at the point of common coupling. To ensure the multifunctional feature, we propose a direct power control (DPC) which is applied to eliminate line current harmonics, compensate reactive power and feeding wind power into the utility. The simulation results show that the control algorithm of system is effective for eliminating harmonic currents, reactive power compensation and inject the active power available from the PMSG wind turbine into the load and/or grid. Key Words: Wind Energy Conversion System, Double Fed Induction Generator, Self-Excited Induction Generator, Self- Excited Induction Generator, Permanent Magnet Synchronous Generator, Shunt Active Power Filter, Static Compensator, Voltage and Frequency Controller, Photo Voltaic Generator.

Optimizing the integration of photovoltaic and wind energy systems for enhanced efficiency

This paper presents a novel integration scheme of solar Photovoltaic (PV) with a large-capacity Doubly Excited Induction Generator (DFIG)-based wind energy system. The proposed scheme leverages both the grid and rotor-side power converters of the DFIG to inject PV power into the grid, eliminating the need for a dedicated converter for PV power processing and offering a cost-effective PV-grid integration solution. The system effectively delivers a substantial amount of PV power to the grid when compared to an equivalent rating inverter used in conventional PV-grid systems. Moreover, the proposed scheme prevents circulating power during sub-synchronous operation in the presence of solar radiation, enhancing overall system efficiency. Additionally, the system's stability benefits from turbine inertia, allowing for higher PV penetration into the power grid. The intermittent complementary nature of solar PV and wind energy sources significantly improves the utilization of the converters. Furthermore, the proposed scheme minimally impacts Maximum Power Point Tracking (MPPT) for PV and wind sources, except in rare environmental glitches, which the PV power control algorithm is adept at handling. The study provides a comprehensive system model used to design the control strategy, supported by analysis, simulations, and experiments conducted on a laboratory prototype.

An Efficient Method for Feature Extraction and Selection in Power Quality Recognition

—Since decade, many time-frequency analysis methods with combination of classifiers have been studied in literature for recognition of power quality (PQ) events. In these studies, feature extraction and selection have a vital role to enhance PQ classification accuracy and to reduce computational complexity for PQ recognition. This paper presents a new method to detect and classify PQ disturbances based on modified Stockwell Transform (ST) for extraction of features and Hybrid Grey Wolf Optimization (HGWO) for feature selection along with K Nearest Neighbor (KNN) classifier. Simulation of the proposed method using MATLAB is carried out through a wide range of eighteen synthetic PQ events to validate the effectiveness of the selected features. Further, an experiment is extended for six classes of real PQ events acquired from self excited induction generator (SEIG) system in a laboratory experimental setup. Proposed method is also employed on those real time data to study the classification accuracy performance. In these experiments, an impressive accuracy of 99.94% and 99.3% for synthetic and real time PQ event data, respectively are reported. Hence, it is observed from result analysis, this proposed method can be utilized for recognition of PQ events in real time power system.

An Optimized Model of Single Phase Self Excited Induction Generator

This paper illustrates the newly developed specially designed single phase self excited induction generator. All possible configurations for winding arrangement have been attempted to obtain the best output from the model. The earlier configurations were found incomplete to obtain the optimum output from the single phase induction machine as an induction generator. The proposed model is unified, optimum and accurate for inculcating the performance of single phase induction generator. The model design as well as its development of 3.7 kW, 50 Hz and 4-pole single phase SEIG is presented using simulink in MATLAB. The 4 possible configurations are designed for single phase SEIG, the objective function is to reduce total harmonic distortion (THD) and optimize the model parameter. The results were demonstrated experimentally validated using SPEED software. A standard available IEC 132 frame size is used for development of proposed model and the results found are prominent.
 HIGHLIGHTS
 
 It is found that there is heavy demand for small capacity power generation in single phase rating as almost electrical appliances are operated on single phase supply. The main objective of this research is to develop a novel and a specially designed SEIG and to analyze its performance analysis
 The 1-phase SEIG is proposed with rating 3 - 5 kW. The input parameter for single phase SEIG such as power, voltage, impedance, frequency, pole pair the stator/rotor resistance etc are theoretically analyzed
 Afterwards the parameters are act as input for SPEED software the results are obtained and found to be impressive one with practical applications
 Four possible configurations for a single phase SEIG are proposed. The four possible configurations have been attempted to achieve the objective of research. On comparing the performance of these models, it has been observed that the model - “Short pitch (1-8) Double layer distributed winding” gives good performance in terms of reduced THD, sinusoidal m.m.f. waveforms
 
 GRAPHICAL ABSTRACT

Experimental investigation on performance comparison of self excited induction generator and permanent magnet synchronous generator for small scale renewable energy applications

This paper presents an experimental performance comparison of self-excited induction generator (SEIG) and permanent magnet synchronous generator (PMSG) for renewable energy-based standalone applications. These two generators have gained popularity in constant speed prime mover-driven power generation systems due to their inherent advantages. Many researchers have proposed various configurations with and without power electronics and battery energy storage for SEIG and PMSG systems. In the isolated systems, the maximum generation and load capacities are known and the primary goal is to maintain a constant voltage and frequency across load terminals. In this context, the performance comparison of both generators is needed to identify the simple, viable, and economical solution for a dedicated source and fixed isolated loads. Therefore, an attempt is made on the performance analysis of micro-hydro turbine driven SEIG and PMSG with resistor heating and induction motor driven pump load applications and compared experimentally to identify suitable voltage regulated generator. The proposed study is not employing power electronic based switches for reactive power (VAR) compensation to make the system cost effective with ease of operation. The working procedure and minimum requirements are discussed in detail for the experimental purpose. Keywords - Self-excited induction generator (SEIG), permanent magnet synchronous generator (PMSG), renewable energy sources, power generation, isolated loads, voltage regulation (VR).

Experimental Investigations on Loading Capacity and Reactive Power Compensation of Star Configured Three Phase Self Excited Induction Generator for Distribution Power Generation

Self excited induction generator (SEIG) is gaining popularity for off-gridpower generation due to the inherent advantages. This paper presents a pri-mary experimental investigative study on the performance of three-phase starconfigured SEIG (Y-SEIG). The aim of the experimental work is to identifya simple and cost-effective scheme of self-excitation and reactive power(VAR) compensation among the six possible operational configurations.From the investigated results, it is found that the capacitor excitation and VAR compensation in the delta connection scheme give the better performance.Experimental test procedure and obtained values of steady state analysis ofSEIG for calculation of minimum excitation capacitance are also highlightedin this paper.

Effects of induction machine parameters on its performance as a standalone self excited induction generator

A squirrel cage induction machine (SCIM) when aggregated with relevant capacitances and a prime mover, acts as self-excited induction generator (SEIG). As it hosts energy conversion the parameters of SCIM have considerable impact on the power extraction capability of SEIG. An aspect which is missing from the available research on SEIGs is evaluation of the affects of its rotor’s moment of inertia (J) and per-phase stator winding resistance (Rs) on performance indices. This work investigates the impacts of these factors on a SCIM’s performance as series compensated, short shunt SEIG. The study considers two distinctly designed SCIMs, in terms of J and Rs, operated as SEIG. In order to simulate their performance a stationary reference frame dq model including non-linear saturation and cross coupling effects is developed and verified experimentally. Several key investigations based on series capacitance selection, losses and efficiency, on-load performance with different power factor loads, transient performance with load perturbation and variable speed operation are carried out. The study reveals that SEIG with high J and lower Rs gives considerably better performance than its counterpart. The conclusions reported in the study are important especially for standalone/off grid application of SEIGs.

Design and implementation of constant flux controller for VSI assisted SEIG feeding induction motor pump

In small scale, stand-alone, wind-power generation employing self excited induction generator (SEIG), water pumping using an induction motor is a typical application. In this paper, a simple voltage regulation scheme for the constant flux operation of the inverter assisted SEIG feeding three-phase induction motor pump is presented. The behaviour of DC-link voltage, frequency, amplitude modulation index (ma) and the shaft speed for load and speed perturbations are discussed in detail. Also, the overall active and reactive power flow for constant flux operation at the point of common coupling (PCC) is analysed. The proposed work presents a simple and reliable controller for SEIG-based stand-alone system for frequency-dependent loads using only a DC-link voltage sensor. Detailed system simulations are performed using Matlab/Simulink and the results of a laboratory prototype are presented to validate the theoretical analysis and practical operability of the proposed system.

Identification of the best topology of delta configured three phase induction generator for distributed generation through experimental investigations

AbstractResearch on Self –excited induction generator (SEIG) brings a lot of attentions in the last three decades as a promising solution in distributed generation systems with low cost investment. There are two important fixations to attend in the operation of SEIG based systems, a) excitation and b) voltage regulation. Many procedures are reported regarding selection of excitation capacitance in the literature, based on state-state analysis, dynamic modeling, empirical formulas and machine parameters which involve various levels of complexity in findings. Moreover, the voltage regulation is the main challenge in implementation of SEIG based isolated systems. To address this problem, many power electronic-based schemes are proposed in the literature and but these solutions have few demerits importantly that additional cost of equipment and troubles due to failure of protection schemes. In particular, the installation of SEIG takes place at small scale in kW range in remote/rural communities which should not face such shortcomings. Further in case of off-grid systems, the maximum loading is fixed based on connected rating of the generator. This paper presents the various methods to find excitation capacitance and illustrates an experimental investigation on different possible reactive power compensation methods of delta connected SEIG and aimed to identify a simple method for terminal voltage control without power electronics. In this experimental work, the prime-mover of the generator is a constant speed turbine, which is the emulation of a micro/pico hydro turbine. From the results, it is found that a simple delta connected excitation and delta configured reactive power compensation limits voltage regulation within ±6% while maintaining the frequency of ±1%, which make feasible of the operation successfully in remote electrification systems.

Stability Testing and Restoration of a DEIG-Based Wind Power Plant with Indirect Grid Control Strategies

ABSTRACT In the current scenario, because of government policies, environmental factors, and technological improvements, there is a rapid growth in renewable energy sector. The emphasis is to obtain better system performance by effective resource utilization and providing security and reliability. This paper discusses the design and implementation of indirect grid control of a wind power plant by controlling the parameters in both grid and rotor side converters. The proposed system consists of Doubly Excited Induction Generator (DEIG) with Wind turbine system (WTS) and Mechanical and Electrical Power Controlling Systems (MPCS-EPCS). Various transmission line faults (symmetrical and asymmetrical faults) incur power imbalances in power grid. The developed MPCS and EPCS are helpful to perform grid monitoring and controlling under different types of faulty conditions. The MPCS monitors the effective source utilization and EPCS helpful for matching the grid energy levels under normal and faulty conditions. Modification in the converter topologies to minimize the impact of adverse effects of faults on the DEIG-WTS and to improve resiliency in the power grid is also discussed. To improve the stability and enhancing resource utilization to improve the efficiency of the overall system with the enhancement of fault voltage ride-through capability in DEIG-WTS under fault conditions are also considered. The stability of the system is tested under steady-state and dynamic-state conditions by applying faulty conditions in MATLAB/Simulink environment.

Battery‐supported unified power quality controller for small hydro‐based isolated power generation

In this paper, a battery-supported unified power quality controller (UPQC) for a small hydro-based isolated power generation is investigated as a voltage and frequency controller. The self-excited squirrel cage induction generator driven by constant power prime mover (small hydro turbine) has unacceptable voltage, frequency and power quality under non-linear loads. The battery-supported UPQC-based voltage controlled-voltage source converter is designed, modelled and simulated in MATLAB environment. Here UPQC has series and shunt converters with a battery and it is used to feed the local loads. This small distributed power generation system is capable to feed unbalanced non-linear loads because a shunt converter is used to take care the compensation of unbalanced loads and it always maintains the source currents balanced and sinusoidal. Moreover, a series converter is used to inject the series voltages in the self-excited squirrel cage induction generator terminals to regulate the common coupling point voltage during unbalanced non-linear loads. Performance of a battery-supported UPQC is also validated experimentally using a laboratory prototype of a 3.7 kW, 230 V, 50 Hz capacitor excited induction generator.

Transient Analysis of self excited Induction generator with ELC

— Fast depletion of fossil fuels has drawn attention towards the use of nonconventional energy sources like wind, biomass, tidal/wave, and small hydro potential. In remote locations, harnessing of electrical energy from such local resources can be cheaper and easier compared to grid connection, which involves long transmission lines and associated losses. A micro-hydro system using natural hydro potential with minimal civil works is a strong candidate in this race. Uncontrolled low head turbines are prescribed for such applications. In this paper, a transient analysis of a self-excited induction generator (SEIG) with electronic load controller (ELC) utilized in stand-alone micro-hydro power generation employing uncontrolled turbines. In view of the need to fed single phase loads from such systems, the transient behavior due to switching in of such loads is of interest and is carried out here. A composite mathematical model of the total system has been implemented by combining the modeling of prime mover, SEIG, ELC, and load. Simulated results are matched with the experimental ones, obtained on a implemented prototype of an SEIG-ELC system for the starting of an IM and switching in a resistive load. To starting of an IM, a star/delta starter is utilized to avoid inrush current.

Design and development of a new three‐phase AC‐DC single‐stage wind energy conversion system

The prevalent use of the diode bridge rectifier in three phase wind energy conversion systems decreases the efficiency of the power generation. In standalone wind energy generation, bridgeless converters can address this problem by eliminating the front-end diode bridge rectifier. This work presents a novel single-stage three-phase bridgeless AC to DC c̀uk converter for wind energy conversion systems. The proposed converter is designed to work in discontinuous inductor current mode because of its inherent power factor correction and less harmonic distortion. Using body-diodes of the MOSFETs per phase component reduction is also done in this converter. A unique maximum power point tracking technique is developed for this converter using three-phase voltages and currents, instead of the DC link states. A wind energy emulation system using a DC motor and self excited induction generator is used to test the laboratory prototype of the proposed converter.

An optimum three-stage stator winding connections for wind-driven stand-alone self-excited induction generators for enhanced annual energy output

A special three-phase stator winding consisting of a parallel combination of delta and star is proposed for wind-driven, self–excited induction generators (SEIGs), increasingly used for supplying isolated loads. This winding configuration enables the SEIG to be operated over a wide range of wind speeds, in three stages. The winding is set at parallel delta-star connection at higher wind speeds and then changed to conventional series delta and series star connections at medium and low wind speeds, respectively. An equivalent circuit has been developed for SEIG with this unconventional winding, and the expressions for the evaluation of its performance characteristics have been derived. A method of determining a suitable value of excitation capacitor bank has also been formulated using genetic algorithm. Taking an example of a 2.2 kW, three-phase SEIG, its predetermined characteristics and the corresponding experimental results have been presented. Taking the wind data from an actual wind farm, the annual energy output obtainable from this generator is also estimated. The proposed switching scheme is thus shown to be optimum for covering a wide range of wind speeds. A cluster of several such generators can lead to the establishment of battery charging stations and formation of micro-grids.

Modeling and Analysis of a Six-Phase Self Excited Induction Generator Feeding Induction Motors

Conventionally, the multi-phase self-excited induction generators (SEIGs) have been analysed either with resistive or static resistive-inductive loads. This endeavor proposes a simple six-phase SEIG (6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG) topology feeding induction motors (IMs). Shunt and series capacitances provide excitation current and load voltage compensation for 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG. A stationary reference frame dual dq model including non-linear saturation and cross coupling effects is integrated with IM loads for simulating 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG-IM set. Sub-synchronous resonance (SSR) is associated with series compensated SEIGs. A series capacitance 2.5 times the excitation capacitance causes SSR in studied 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG as starting of IMs is attempted from its terminals. SSR induces low frequency oscillations and spikes load voltage and current amplitudes. A method to overcome SSR is proposed by evaluating a critical value of series capacitance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$C_{se,cr}$</tex-math></inline-formula> ). Equipped with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$C_{se,cr}$</tex-math></inline-formula> and excitation capacitance the 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG successfully sustains starting, no-load build-up and rated load operation of IMs. A comparison with its equivalent 3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> counterpart reveals that 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG manages reactive power more efficiently as its optimum capacitance requirement reduces by 1.9 to 3.75 times, it incurs 0.4% to 2.8% lesser %THDs in output parameters and exhibits greater operational flexibility. Experimental results are obtained on an open end winding induction machine operated as SEIG.

Asynchronous Grid Connection of a Cage Induction Generator Excited by a Power Electronic Converter

This article presents an analysis of grid connection of an excited induction generator, where an inrush current is significantly reduced and voltage drop in the local grid is eliminated. In the proposed method, generator connection to the grid is done at the moment when the generator voltage vector equals the grid voltage vector, but the generator frequency differs from the grid frequency. Excitation of the induction generator is provided by a power electronic converter, which is rated only on the rated reactive power of the generator. Moreover, when the generator is connected to the grid, the converter satisfies reactive power demand of an induction generator, according to the requirements from the distribution system operator. The simulation and laboratory tests were conducted with a 7.5 kW induction generator.

Cascaded H-Bridge Inverter for Wind Driven Isolated Squirrel Cage Induction Generators

Abstract: This paper describes the simulation andharmonics analysis of cascaded five-level H-bridge invertersfed induction motor load drive for islanding mode applications.The self – excited induction generator (SEIG) fed H-bridgeMulti-Level Inverter (MLI) for wind energy conversionsystems is chosen for several islanding mode applications. Inthis paper, the SEIG (for standalone systems) fed cascaded fivelevel inverter for induction motor load applications are clearlyexplained with the help of MATLAB / SIMULINK models. Thegenerated voltage of the wind driven SEIG is mainly dependingon the wind velocity fluctuations and appropriate loadconditions. The five level cascaded inverters have interfacewith the wind driven SEIG. By choosing appropriate value ofModulation Index (MI), the variable voltage and variablefrequency of the generator can be finely controlled. Thesimulation and harmonic analysis of the proposed inverter willbe discussed, and the total harmonic distortion of statorcurrent for different modulation index at different switchingfrequencies are evaluated and the speed and torque ofinduction motor for different load torques are plotted.Index Terms: Self – Excited Induction Generator (SEIG),Variable speed Wind Turbine, Multi Level Inverter (MLI),Induction Motor (IM), Modulation Index (MI).

하이브리드 전기추진시스템용 SEIG 및 PMSG의 출력 비교 분석

This paper deals with comparison analysis on output characteristics of two types of generators for a hybrid electric propulsion system (H-EPS) consisted of an engine-driven system and an electric driven system. Main components of H-EPS consists of two parts. One is a power generation system with efficient electric power generation performance even in a variable speed condition of a diesel main engine, and the other is a charging system with efficient storage performance of the electric energy. The generator of power generation system for the H-EPS is required to have the highest reliability and stability, despite isolation at sea and poor engine room environment. In addition, it should be compact structure with high output and lightweight in relation to volume. For the purpose of this study, we selected a self excited induction generator (SEIG) and a permanent magnet synchronous generator (PMSG) for H-EPS, and analyzed their output characteristics through several experiments. By comparing the experimental results, it was clear that PMSG exhibited better performance than SEIG as the generator for H-EPS.

Design and Simulation of Current Sensor based Electronic Load Controller for Small Scale Three Phase Self Excited Induction Generator System

In standalone renewable energy systems, the power balance methods must exist to match the generated power and load demand; otherwise the excess power creates the disturbance in terms of voltage and frequency fluctuations. This paper presents a design and simulation of an electronic load controller (ELC) for the power balance in constant power prime mover-coupled three phase self-excited induction generator (SEIG) system. A current sensor based ELC is designed in such a way that to operate the generator unit always at its full capacity by coordinating between the two load systems termed as main and dump load. The controller unit has an uncontrolled 3-phase full-bridge rectifier circuit, a logically controlled insulted-gate bipolar transistor (IGBT) chopper switch, and a current sensor. The current sensor provides the feedback signal to the gate trigger circuit of IGBT and which inevitably controls the ON/OFF position of the switch. The ON condition of switch means a partial or full portion of generation power is diverted to the dump load, and the sum of both loads is equal to the rated capacity of SEIG. The proposed system is simulated in MATLAB, and the power balance is achieved with help of ELC. The voltage regulation of SEIG is addressed by adding extra reactive power (VAR) compensation. Further, in this study, the basic configuration of SEIG and the importance of self-excitation phenomena for voltage generation are also highlighted.