Single-phase Self-excited Induction Generator Research Articles

State‐of‐the‐art and comprehensive study of renewable energy sources based microgrid with single‐phase self‐excited induction generator

This study presents a comprehensive study of microgrid systems using a single-phase self-excited induction generator (SEIG) using renewable energy sources (RESs) and their integration with other energy sources. It investigates on the use of a single-phase two-winding SEIG for off-grid single-phase power generation from different RESs. Various solid-state controllers are implemented for each configuration. This is the first time, such an attempt is made to use a specially designed SEIG for sustainable energy application to feed single-phase loads vastly prevalent in isolated and distant locations in accessible to the grid. This work has great importance due to the non-availability of the power in remote regions in developing countries. Moreover, there is a need to use local RESs such as bio, hydro, wind in combination with the solar energy. The present global need to generate pollution free electricity makes this work quite important. Thus, this study presents a comprehensive review of different modes of SEIG using RESs for single-phase power generation realising the microgrid feeding a combination of practical loads with viable and successful controllers to ensure desired quality power across loads.

Performance Characteristics of Single-Phase Self-Excited Induction Generators with an Iron Core of Various Non-Grain Oriented Electrical Sheets

This paper deals with the computation of the performance characteristics of the single-phase self-excited induction generator by field–circuit method. It presents and compares previously unpublished results—self-excitation and no-load characteristics of the generator for different rotor speeds, and complete load steady-state performance characteristics for various types of the core materials. The discrepancies between the performance characteristics of the generator for the catalog’s magnetization curves of different types of electrical sheets and for an actual magnetic core of the generator for self-excitation transients and load steady-state are presented. The results may be useful for designing new constructions of single-phase self-excited induction generators.

Power quality solutions for effective utilization of single-phase induction generator using voltage source converter

ABSTRACT In this paper, the effective utilization of single-phase self-excited induction generator (SEIG) with improved power quality features with the help of voltage source converter (VSC) is presented. This generator works as an isolated single-phase distributed power generation system. In this case, the frequency and voltage control of induction generator feeding linear/nonlinear load is carried out using VSC under different operating characteristics. The power quality issues such as reactive power compensation, voltage regulation, harmonics reduction have been addressed. The VSC is operated by the reference current extracted from the distorted load current using adaptive theory-based Improved Linear Sinusoidal Tracer (ILST) control strategy for effective utilization and power quality as per IEEE-519 standards. Nevertheless, the design procedure of the excitation capacitor for self-excitation of the generator is also presented in detail. The design performance of SEIG is also validated through finite element method (FEM). The entire system comprising induction generator, nonlinear/linear load, and VSC along with ILST control algorithm are modeled in MATLAB/Simulink Library. The simulation performance is carried out under various operating conditions and found satisfactory. Also, the system prototype is developed in the laboratory for real-time performance analysis and validation. The results obtained are found satisfactory as per standard.

A Comprehensive Overview of Single–Phase Self-Excited Induction Generators

The use of induction generators for electricity production in small power isolated systems represents the topic for a wide research area. As in such topologies single-phase consumers are predominant, besides three-phase induction generators with adequate balancing circuits, single-phase induction generators qualify as a reliable alternative. In the last 38 years, a significant number of research papers have tackled the problems related to the autonomous operation of single-phase induction generators (SPIGs) such as determining excitation capacitors values and their optimal arrangement, ensuring stable operation in terms of voltage and frequency balancing under varying loads and finally enhancing the quality of the energy delivered to the isolated single-phase consumers. While in case of simple topologies the operation of SPIGs is mainly investigated for fundamental electric parameters dependence with loading, excitation capacitance and speed, the use of power electronics based converters ensures stable operation over a wide range of varying/non-linear loads. This paper presents a comprehensive overview of the literature dedicated to SPIGs, focusing on several significant aspects such as main topologies, modeling, steady-state analysis and performance investigations.

Analysis of a proposed connection for the two-winding single-phase self-excited induction generator operating at constant voltage and frequency

This paper introduces the steady-state and dynamic behaviors of a proposed connection for the two-winding single-phase self-excited induction generator (TWSPSEIG) equipped with an excitation capacitor and a compensation capacitor for operation at constant load voltage and frequency irrespective of the no-load or different load conditions. The performance equations at steady-state conditions are attained by applying loop impedance method via the exact equivalent circuit models of the TWSPSEIG based on the double revolving field theory. Keeping the values of the excitation capacitor and the compensation capacitor as unknowns, two second-order equations, for given values of generator parameters, prime mover speed, frequency and load impedance, are derived. These equations are solved using simple iterative method to calculate the optimum values of the two capacitors under the constraints that the load voltage and frequency are constant. The range of capacitor variations for variable load at variable prime mover speed is also calculated. The steady-state results are verified by developing the dynamic model of the proposed connection incorporating its nonlinearity behavior and various no-load and load conditions. The dynamic behavior of the proposed connection proves the capabilities of the proposed configuration and calculation method to maintain both the load voltage and frequency constants. A comparative study between the performances of the proposed connection and the traditional connection of the TWSPSEIG is presented to illustrate the merits of the proposed connection.

Comparative analysis of single-phase self-excited induction generators of various rotor cages

The paper deals with a simulation study of influence of conductive material of the rotor squirrel cage on output characteristics of single-phase self-excited induction generators. For calculation of performance characteristics, two-dimensional field-circuit model of the single-phase induction generator was applied. A comparison of self-excitation waveforms of terminal voltage and load characteristics of the generators for rotor bars of the same shape, made of aluminium and copper, was presented. The obtained simulation results by the field-circuit model and analysis may be utilized for designing new constructions of single-phase self-excited induction generators as well for modifying construction of the generators designing on the base of general-purpose single-phase induction motors.

Influence of shape and material of rotor bars on performance characteristics of single-phase self-excited induction generators

PurposeThe purpose of the paper is to present an analysis of an influence of shape and material of rotor bars on the process of self-excitation and performance characteristics of single-phase, self-excited induction generator (SP-SEIG).Design/methodology/approachThe presented analysis is based on the results of transient simulations of SP-SEIG performed with the use of field-circuit model of the machine. Four various shapes of the rotor bars and two different conductor materials were investigated. The results for the base model with rounded trapezoidal rotor slots were validated by measurements.FindingsAn improvement of the performance characteristics – the extension of the stable operating range of the generator – was obtained for rectangular copper rotor bars. The improvement is the result of strong skin effect in the squirrel rotor cage. Application of round rotor slots results in shorter time of voltage build-up during the self-excitation of the generator caused by less apparent deep bar effect in round bars.Originality/valueThe originality of the paper is the application of the copper rotor cage in the single-phase, self-excited induction generator. Its use is beneficial, as it allows for extension of the range of stable operating range. The results may be used for designing new constructions of the single-phase, self-excited induction generators, as well as the constructions based on general purpose single-phase induction motors.

A new model of self-excited induction generator to feed a single phase load with an application in lighting animal farm

This paper presents a new model of self-excited single-phase induction generator, used by a three-phase machine for lighting animal farm through biogas energy. The designs and applications of the previous generator models have been found to be very complex, for this reason simple and effective model of SEIG is proposed. The transient equations of the proposed model were represented by SIMULINK blocks, while the steady state equations by electrical equivalent circuit. The model is derived from Steinmetz connection circuit, stationary reference frame qd-axes theory and symmetrical component theorem. Experimental and simulation using MATLAB are the two methods used to prove the validity of the present model. Results obtained from the two methods were closed to each other. Also, the perfect balance point was achieved at unity power factor. This application proved that the output voltage and current have sinusoidal waves which implying that the generator was operating efficiently.

A New Model of Self-Excited Induction Generator (SEIG) to Feed a Single Phase Load with an Application in Lighting Animal Farm

This paper presents a new model of self-excited single-phase induction generator, used by a three-phase machine for lighting animal farm through biogas energy. The designs and applications of the previous generator models have been found to be very complex, for this reason simple and effective model of SEIG is proposed. The transient equations of the proposed model were represented by SIMULINK blocks, while the steady state equations by electrical equivalent circuit. The model is derived from Steinmetz connection circuit, stationary reference frame qd-axes theory and symmetrical component theorem. Experimental and simulation using MATLAB are the two methods used to prove the validity of the present model. Results obtained from the two methods were closed to each other. Also, the perfect balance point was achieved at unity power factor. This application proved that the output voltage and current have sinusoidal waves which implying that the generator was operating efficiently.

Variable learning adaptive gradient based control algorithm for voltage source converter in distributed generation

This study presents an adaptive control algorithm known as variable learning and adaptive gradient based least mean square for improving the power quality features in standalone distributed generation. Further, frequency and voltage are regulated to set reference value at the terminal of the self-excited single-phase induction generator running in isolated mode. The variable learning and gradient-based least mean square (VLGLMS) algorithm is insensitive to its gradient, step size and sensors noise unlike least mean square algorithm whose convergence performance is influenced by the step-size parameter. In this study, VLGLMS is utilised to compute the active and reactive weights of fundamental load current for estimation of the reference source current. The sinusoidal reference current estimation is followed by generation of gate pulses for operating the DSTATCOM for improving the power quality features of single-phase induction generator based distributed power generation system. A prototype model is developed using MATLAB SIMULINK and tested in the laboratory under linear and non-linear loads. Based on implementation, the performance of control algorithm is validated and obtained results are found satisfactory.

Behaviour of single-phase self-excited induction generator during short-circuit at terminals

PurposeThe purpose of this paper is to present analysis of short-circuit transients in a single-phase self-excited induction generator (SP-SEIG) for different capacitor topologies.Design/methodology/approachThe paper presents field analysis of the short-circuit problem in the SP-SEIG on the base of two-dimensional field-circuit model of the generator.FindingsThe carried-out field computations of the tested SP-SEIG show that the self-excited induction generator is intrinsically protected from the results of sudden short-circuit, as output voltage and current drop rapidly to zero. Short-circuit is a problem when a series capacitor is used to improve output voltage regulation. Experimental results show that re-excitation of the generator is possible after the short-circuit is removed.Originality/valueThe originality of the paper is the presented analysis of short-circuit transients at terminals of SP-SEIG. A finite elements method-based field circuit model was used. The simulation results were validated by the measurements conducted on a laboratory test setup.

Improving performance of a single-phase self-excited induction generator by modification of an excitation winding

Improving performance of a single-phase self-excited induction generator by modification of an excitation winding

Field-circuit analysis and measurements of a single-phase self-excited induction generator

Abstract The paper deals with a single-phase induction machine operating as a stand-alone self-excited single-phase induction generator for generation of electrical energy from renewable energy sources. By changing number of turns and size of wires in the auxiliary stator winding, an improvement of performance characteristics of the generator were obtained as regards no-load and load voltage of the stator windings as well as stator winding currents of the generator. Field-circuit simulation models of the generator were developed using Flux2D software package for the generator with shunt capacitor in the main stator winding. The obtained results have been validated experimentally at the laboratory setup using the single-phase capacitor induction motor of 1.1 kW rated power and 230 V voltage as a base model of the generator.

Modified Electronic Load Controller for Constant Frequency Operation With Voltage Regulation of Small Hydro-Driven Single-Phase SEIG

This paper is aimed at design and implementation of a modified electronic load controller (MELC) for constant frequency operation with voltage regulation of a two winding single-phase self-excited induction generator (SEIG) applicable for renewable energy applications specifically for off-grid power generation using a small-size hydro energy. The system frequency is maintained constant at a reference level for fixed as well as variable input mechanical power to the prime mover experienced in small hydro systems due to seasonal variations. The point of common coupling (PCC) voltage is also regulated by the controller at varying loads by controlling the power flow to the dump load. The proposed MELC is developed for the constant frequency generation and voltage regulation of single-phase SEIG with frequency as a feedback variable.

Implementation of Voltage Controller of Single-phase Self-excited Induction Generator

This article presents the implementation of a new voltage controller for a single-phase two-winding self-excited induction generator that is suitable for renewable energy applications, such as bio energy and diesel engine. The proposed voltage controller regulates the terminal voltage within ±5% at varying resistive, inductive, and dynamic loads. The proposed voltage controller uses only one shunt capacitor (Csh) controlled using back-to-back connected thyristors to vary the reactive power for voltage control of the self-excited induction generator. The power loss in this shunt capacitor (Csh) is 2 W for a 5-kW self-excited induction generator, which is much less compared to its counterparts, such as the static compensator. The proposed controller is useful for remote applications for low power generation up to 5 kW. The proposed controller also regulates the system voltage for small variations in the prime mover speed due to its variable input mechanical power as well as during load perturbations.

Analysis of self-excitation and performance characteristics of a single-phase self-excited induction generator by field-circuit method

Purpose – The purpose of this paper is to present analysis of an influence of rotor slots opening on self-excitation process, terminal voltage and performance characteristics of the single-phase self-excited induction generator (SPSEIG). Design/methodology/approach – The paper presents field analysis of the self-excitation problem in the SPSEIG and performance characteristics on the base of two-dimensional field-circuit model of the generator. Findings – The carried out field computations of the tested SPSEIG with closed rotor slots showed that only an initial voltage across the excitation capacitor of about nominal value (230 V) causes successful self-excitation of the generator. It was also proved that the suitable opening of the rotor slots, beside remnant flux density in the rotor core, facilitates self-excitation in the generator. Since in working applications initially charging of the capacitor to almost nominal voltage may cause a problem, therefore employment of semi-closed rotor slots in the SPSEIG would be proper solution. Originality/value – The conducted simulations, validated by laboratory tests showed that not only suitable excitation capacitor capacitance and rotor speed are needed to obtain desired terminal voltage of the generator, but also suitable initial voltage across the capacitor in auxiliary stator winding is very important and necessary for reliable self-excitation of the single-phase induction generator with closed rotor slots. The employment of semi-closed rotor slots in the SPSEIG makes the self-excitation more effective.

Enhanced Power Generation From Two-Winding Single-Phase SEIG Using LMDT-Based Decoupled Voltage and Frequency Control

This paper proposes a leaky minimal disturbance theory (LMDT)-based decoupled control of voltage and frequency for two-winding single-phase self-excited induction generators (SEIGs) for enhanced power generation and power quality improvement. Single-phase two-winding SEIGs are normally designed with 33% derated capacity in comparison to three-phase SEIGs of the same frame size. Using single-point operation performed by the proposed decoupled voltage and frequency controller (DVFC), the two-winding single-phase machine can generate enhanced power output, nearly 33% higher than its normal capacity. It is equal to the power generated by a three-phase machine with the same frame size. The DVFC consists of a voltage source converter (VSC) and a closed-loop controlled dump load. A single-phase VSC is used for harmonics and fundamental reactive power compensation for system voltage control and harmonics mitigation. The control of VSC is achieved using an LMDT-based control algorithm. The minimal disturbance theory-based control algorithm is used for potentially fast convergence and fast dynamic response, whereas the leakage factor is added for improving the steady-state performance of the system. The LMDT control-based VSC-battery energy storage system scheme is also implemented for the voltage and frequency control of a single-phase SEIG. Both schemes are implemented in real time using a digital signal processor.

Loading Performances of Low-Power Low-Speed Single-Phase Induction Generator with Energy Saving Lamps

The increasing use of energy saving lamps provides additional benefits to the application of low-power low-speed self-excited induction generators resulted from capacitor motor modification. Reactive power requirement of the generator can be provided from the capacitive nature of the lamps, while at the same time it is delivering active power to loads. Any loading change will automatically increase or reduce reactive power supply to generator. Results of experiments show that low-power low-speed single-phase self-excited induction generator is more robust and suitable for this kind of loads. Generator does not lose its voltage when experiencing abrupt change of loads. This robustness makes the generator suitable for the use in low-capacity hydropower generation in remote areas being commonly not covered by national electricity grid.

Performance characteristics evaluation of a single-phase selfexcited induction generator by a field-circuit model

Performance characteristics evaluation of a single-phase selfexcited induction generator by a field-circuit model

Adaptive noise suppression filter based integrated voltage and frequency controller for two‐winding single‐phase self‐excited induction generator

In this study, an adaptive noise suppression filter based control algorithm is proposed for integrated voltage and frequency controller (IVFC) of a speed governor-free hydro turbine driven single-phase self-excited induction generator (SEIG). A voltage source converter (VSC) is employed to control the terminal voltage of SEIG with adjustable reactive power. It also mitigates the harmonics injected by non-linear loads in the SEIG system. A resistive dump load with a chopper is connected at dc-bus of VSC. The dump load is controlled to regulate the system frequency at varying loads and mechanical power input to the unregulated micro hydro turbine during seasonal changes. The frequency estimation and phase shifting technique is used for frequency estimation and for generation of quadrature signal of point of common coupling voltage. The proposed IVFC is designed, developed and implemented using a digital signal processor for a two-winding single-phase SEIG of 5 kW rating and test results are presented to demonstrate its performance under steady state and dynamic conditions.