Model Of Self-excited Induction Generator Research Articles

Performance Evaluation and Dynamic Characteristics of a Self-Excited Induction Generator for Pico Hydro Power Plants

The dynamic performance of an isolated three-phase squirrel cage self-excited induction generator (SEIG) in a Pico Hydro Power Plant (PHPP) is examined in this work. The investigation is carried out with the help of MATLAB/Simulink for mathematical modeling and simulation of the proposed system under various operational situations. The SEIG model, which was created using the steady-state equivalent circuit approach, included the electrical, magnetic, and mechanical components of the SEIG and PHPP. The dynamic behavior of the SEIG is explored under a variety of operating situations. The effects of load variations, speed fluctuations, and other disturbances on the voltage and frequency of the generator are examined. The experiment results were used to validate the simulation results. This research has implications for the design and optimization of PHPP using SEIGs.

Step by step approach for developing analytical and experimental research facilities of a three-phase self-excited induction generator

Self-excited induction generators (SEIGs) have been rigorously investigated in last few decades owing to their suitability for standalone renewable energy applications. Various issues pertaining to their modeling and control are quite aptly addressed in several analytical and experimental studies. However, these analyses are often focused on elaboration of proposed innovations and findings while the important details on modeling and implementation of SEIGs are left to be explored by readers. In this paper, a step by step approach for the mathematical modeling of three-phase self-voltage regulating, short shunt SEIG in stationary reference frame is explained. Subsequently, the developed d-q model of SEIG is implemented in terms of a simulation model. The developed model is then employed to carry out performance analysis of 3-phase, 2.2 kW SEIG supplying R-L load. All the results are verified with good accuracy in a SEIG test-rig whose details are included in the paper. The prime objective of this work is to provide a consolidated source for developing research resources of a self-voltage regulating three phase SEIG.

Steady-State Analysis Based on Space Vector Model of Self-Excited Induction Generators

In order to attain more optimization for the procedure of transient and steady-state operation performance analysis and evaluation of self-excited induction generators (SEIGs), the paper converts the state-space transient mathematic model with real domain into the space vector transient model with complex domain based on the same two-phase stationary reference frame, described by which the physical systems can apply extendedly the holistic analysis approach based on Lyapunov stability theory proposed in real domain. Through equivalent analysis, the extended form of the steady-state conditions and its mathematic description into the complex domain is obtained, that is, the extended quasi limit cycle and the steady-state operating points. The analytic calculation for the extended steady-state condition provides successively the analytic solutions of exciting capacitance, stator frequency, as well as the extended steady state conditions under given rotor speed and magnetizing inductance. The practical calculation example verifies correctness and effectiveness of the approach and the analytic solution of the extended steady-state condition, with engineering reference values.

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.

Modelling and simulation of self-excited induction generator driven by a wind turbine

The excellent specifications of the isolated squirrel cage self-excited induction generator (SEIG) make it the first choice for use with renewable energy sources. However, poor voltage and frequency regulation (under load and speed perturbations) are the main problems with isolated SEIGs. Wide dependence on the SEIG requires prior knowledge of its behaviour with regard to variations in the input of mechanical power and output of electrical power to develop a control system that is capable of maintaining the voltage and frequency at rated values, as far as possible, with any change in the input or output power of the SEIG. In this paper, a mathematical model of a wind energy conversion system (WECS) based on a squirrel cage SEIG with a generalized impedance control (GIC) was built using the Matlab/Simulink environment in a d-q stationary reference frame. A fuzzy logic controller (FLC) was used to control the parameters of the GIC. The training of the FLC was conducted by a neural network through Matlab's Neuro-Fuzzy designer. The results of this paper showed that the trained FLC succeeded in controlling the real and reactive power flow between the SEIG and the GIC system, in which the maximum variation for both magnitude and frequency of the generated voltage with any load or wind speed perturbation will not exceed (0.2 %) for the frequency and (3 %) for the voltage magnitude in both directions. The SEIG model was validated by comparing the results obtained with those of well-known studies with the same rating and operating conditions

Performance Analysis of a Self-excited Induction Generator Mathematical Dynamic Model with Magnetic Saturation, Cross Saturation Effect and Iron Losses

Construction of appropriate mathematical model of plant (object to be modeled) has especially important meaning for designing controller. A reliable and good control performance requires more detailed model. Nevertheless, the latter must be established from at least two viewpoints of preciseness and compactness. In this paper, the considered plant is a self-excited induction generator (SEIG). In order to improve the accuracy, we take into consideration in the SEIG modeling: magnetic saturation phenomenon, cross saturation effect and iron losses. To our best knowledge, this is the first time that the three mentioned phenomena have been integrated into the same and single SEIG model which is presented in an inherent mathematical form. As we will see in the results, the contribution of these three phenomena in the accuracy improvement is really significant. In addition, to achieve compactness of the proposed model, a simpler configuration is obtained for the electrical equivalent circuit associated to the studied model by using Thevenin transformation. The proposed model is built in MATLAB-SIMULINK environment and used to study and analyze the performance of a SEIG under various operating point conditions. The obtained results are compared to measurements and also to the values obtained from models without the three discussed phenomena.

Performance investigation of stand-alone induction generator based on STATCOM for wind power application

Self-Excited induction generators (SEIG) display a low voltage and frequency regulation due to variable applied load and input rotation speed. Current work presents a simulation and performance analysis of a three-phase wind-driven, SEIG connect to a three-phase load. In addition, an investigation of the dynamic operation of the induction generator from starting steady state until no-load operation. It is assumed that the input mechanical power is constant where the rotor of the SEIG rotates at a constant speed. The value of the excitation capacitance which is necessary to the operation of the induction generator also computed to ensure a smooth and self-excitation starting. The output voltage of the generator is adjusted by varying the reactive power injected by STATCOM. A 3-phase IGBT voltage source inverter with a fuel cell input supply is connected as STATCOM which is used to compensate for the reduction in the supply voltage and its frequency due to variation occurred in the applied loads. This work includes introducing a neuro-fuzzyy logic controller to enhance the performance of the SEIG by regulation the generated voltage and frequency The dynamic model of SEIG with STATCOM and loads are implemented using MATLAB/SIMULINK

Dynamic Performance of a Stand-Alone Self-Excited Induction Generator for a Variable Speed Wind Turbine

Induction generators are more appropriate machines for wind energy conversion. Induction generators generally can be operated in two modes i.e. grid or self-excited mode. Among the two, later is of improving importance due to its capability of wind energy conversion (primary) into electrical energy (secondary) for wide range of variations in the operating speed. Poor voltage regulation is observed in machine analysis. Steady-state and transient analysis of self-excited induction generator surveys that such generators are not efficient enough to maintain the frequency and terminal voltage in the absence of conventional controllers but are only used for stator and rotor currents variations. In this paper modeling of self-excited induction generator for wind energy conversion systems is designed and simulated in MATLAB environment. The system is studied for dynamic period simulation during the starting period, and load variation.

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.

Voltage Build-Up Analysis of Self-Excited Induction Generator With Multi-Timescale Reduced-Order Model

Self-excited induction generator (SEIG) has received a lot of attentions for its increasing application in distributed generation systems with the essential feature of low cost. To analysis, the dynamic and transient performance of SEIG, several modifications of the mathematical models have been developed for improving the regulation of voltage and frequency. But these models are still complicated to be used in practice. Based on the transient equivalent circuit, a reduced-order model of SEIG with complex transformation in the two-phase stationary reference frame is realized for the transient analysis of voltage build-up. In this simplified model, the coefficients of the characteristic polynomial with multi-timescale time constants are proposed. Moreover, the physical interpretation of system transient behavior with the reconstructed time constants is established and visualized. Particularly, the upper and lower limits of the capacitance and speed for the SEIG with different parameters variation are simulated and analyzed respectively. The validation and the accuracy of the SEIG model are verified for the transient analysis of the voltage build-up. It is proved that the reduced-order model can be effectively used to insight the dynamic stability of SEIG voltage build-up with the multi-timescale.

A new approach for steady state analysis of three-phase SEIG feeding single-phase load

PurposeThis paper aims to deal with a modified-based approach for the evaluation of the steady state performances of three-phase self-excited induction generator (SEIG) feeding single-phase load.Design/methodology/approachUsing the symmetrical components method, the proposed approach is based on a modified model of unbalanced three-phase SEIG, which is formulated similarly to the well-known model of balanced three-phase SEIG. Owing to this modified model, the determination of the SEIG operating point amounts to the resolution of two semi-decoupled nonlinear equations for two unknowns; the magnetizing reactance and the per-unit frequency. A simple resolution method based on an iterative two-step technique is used. The results obtained by the proposed approach are compared with those given by a conventional approach and are validated experimentally.FindingsThe proposed approach is as accurate as the conventional approach. Further, for the same accuracy degree, the proposed approach permits to speed up the resolution when compared to the conventional approach, as only few iterations are required for the convergence. The proposed approach was also successfully used for the steady state analysis of SEIG under generalized unbalanced loading conditions.Practical implicationsThe determination of the operating point of the generator is based on a modified model of the generator and a simple iterative resolution method. The calculation technique can be implemented on low resource controller to provide online voltage control of the SEIG.Originality/valueThe paper contains two main originalities. The first one consists in a modified formulation of the SEIG model under unbalanced loading conditions. The modified formulation permits the use of the well-known model of balanced three-phase SEIG. Unlike previous ones reported in the literature, the proposed model does not require tedious algebraic manipulations. The second originality is the use of two-step technique to solve the equations, which permits to avoid laborious mathematical derivations and manipulating high-order polynomials.

Dynamic Models of a Self-Excited Induction Generator Taking Iron Losses Into Account: a Comparative Study

This paper deals with the development of a dynamic model of a stand-alone self-excited induction generator (SEIG) taking into account iron losses. It is important to mention that for stable operation of the SEIG, the generator has to operate in the region of magnetic saturation. As a consequence, in any accurate analysis, iron losses must be included. This is particularly the case for small induction machines, where the magnitude of the current in the resistance representing the iron losses can not be neglected compared to that of the magnetising current. The iron losses are represented by means of inserting an equivalent loss resistance in the equivalent circuit of the SEIG. Three places are commonly used to insert the iron loss resistance; in parallel with the magnetising inductance, before the stator leakage inductance or before the stator resistance. Three models are consequently developed and are applied to a 3 kW induction generator. An experimental investigation is carried out to compare the performances of these three models in terms of accuracy and time consumption.

Performance Analysis of a Wind Turbine Based on a Self-Excited Induction Generator (SEIG)

In this paper, magnetic saturation effect of on the self-excited generator (SEIG) used in the micro-grid system is investigated. The effect of the reduction of the electrical quantities generated voltage and its frequency following a purely resistive or inductive balanced or unbalanced load connection are studied in detail. A dynamic model of SEIG in the fixed reference axis dq is developed and simulated using Simulink / Matlab. The results of the simulations of different scenarios are discussed, and conclusions are deduced at the end of this article. These results will be used to study the stability of a micro-grid under a RT-LAB simulator in the future.

Series compensation assessment of self-excited induction generator using genetic algorithm

As the self-excited induction generator (SEIG) is the most suitable for remote and windy areas, so the pre-evaluation of this generator performance is essential. For better voltage profile and power capability, series compensation can be used. This paper presents an assessment of the shunt, short-shunt and long-shunt compensation configurations. A generalized mathematical model of SEIG is presented. The effectiveness of the generalized mathematical model is then tested on a three-phase, 1.5-kW induction generator operating in all configurations. Proposed Genetic Algorithm (GA) model has been implemented to predict the output power capability and corresponding load voltage for each series compensation under various loading conditions. Results obtained from the proposed (GA) model have been compared with the experimental and simulation results. The comparison confirms the validity and accuracy of the proposed GA model as an assessment tool of induction generator with different compensation configurations.

Build‐up steady‐state analysis of wind‐driven self‐excited induction generators

For the contradiction between the increasing importance of the application of induction generator in the new energy power generation such as wind energy and the relative laggard of research on its comprehensive performance, the build-up steady-state analysis is performed for the wind-driven self-excited induction generator (SEIG) system based on the unloaded transient equivalent circuits and its mathematic model of SEIG in the two-phase stationary reference frame. Thus, it obtains the build-up steady-state conditions represented by the unloaded transient mathematic model. On the basis of the result obtained for the build-up steady-state limit cycle condition, the analytic solution for the build-up steady-state operating point condition and the analytic formulas for the limit magnetising induction are further obtained. Example analysis is to test out the only set of analytic solution for the build-up steady-state condition. Thus, the analytic solution for the build-up steady-state condition produces the formulas of the torture and the power factor, which can be applicable to further analysis for the system dynamics and build-up steady-state operating performance, showing practicability and referenced value in engineering.

Analysis of voltage build-up and speed disturbance ride through capability of a self-excited induction generator for renewable energy application

Response of a self-excited induction generator (SEIG) to transient change in input speed as well as no-load voltage build-up is crucial for its steady operation. These two aspects often find very limited mention in the reported work on SEIGs. In this paper, dynamic model of a standalone self-excited induction generator (SEIG) in short shunt compensation connection is developed. The developed model is utilised to investigate inception of self-excitation and voltage build-up with regard to different preconditions. The ride through capability of SEIG subjected to sudden drop in prime mover speed at no-load and the full-load of different power factors is evaluated. The results provide detailed and important insights of SEIG behaviour under such transient conditions. Finally, the load performance of SEIG is carried out with different step loads of unity and 0.8 lagging power factors to evaluate complete dynamics of the machine. The analytical model of SEIG is developed in MATLAB/Simulink. Experimental verification of results is done through an implemented three-phase, 1.5 KW SEIG.

Voltage and frequency regulation of aluminium- and copper-rotor SEIGs incorporating proximity effect

Self-excited induction generators (SEIGs) will play an important role in off-grid wind power generation. To advance understanding of the significance and prospects of SEIGs, this paper elucidates the significance of incorporating the proximity effect in the conventional model of self-excited induction generators. The researchers offer an analytical model to incorporate the proximity effect in the rectangular rotor bars of the SEIG. The model’s accuracy relies on a computer program. The calculated results are experimentally verified in the case of two 7.5 hp aluminium- and copper-rotor SEIGs under open-circuit and static loading conditions, through an exclusive qualitative analysis of terminal voltage build-up at no-load, variation in terminal voltage and frequency, as a function of the proximity effect. The paper examines also the voltage regulation, frequency regulation and excitation capacitance requirements of both aluminium- and copper-rotor SEIGs.

Transient Performance of Series-Compensated Three-Phase Self-Excited Induction Generator Feeding Dynamic Loads

This paper presents the transient performance of a series-compensated three-phase self-excited induction generator (SEIG) feeding a dynamic load such as a three-phase squirrel-cage induction motor (IM). Mathematical modeling and simulation study of SEIG and an induction motor (SEIG-IM) combination is carried out using MATLAB/Simulink. An exhaustive experimental study is conducted using a Mawdsley's generalized machine operating as a SEIG and a three-phase squirrel-cage IM as the dynamic load. The simulated results are compared with the experimental results under various operating conditions of the SEIG such as the following: 1) its voltage and current buildup at no-load; 2) switching of a three-phase squirrel-cage IM to the SEIG terminals without series-compensating capacitors (resulting failure to start an IM); and 3) switching on the same motor with the series capacitors (resulting in successful starting of the IM). A sudden switching of the IM as a dynamic load on the SEIG without the series compensation causes severe transients in electrical and mechanical variables of the SEIG and due to large starting current requirement of the IM, there is a collapse of the terminal voltage of SEIG. However, the use of series compensation in short-shunt configuration of SEIG results in the successful starting of the IM with an improved voltage regulation of SEIG. The phenomenon of subsynchronous resonance (SSR) is observed due to the large variations in the impedance of the SEIG-IM combination and the presence of series capacitors. It causes low frequency oscillations in the IM stator voltages, currents, and its speed. The SSR phenomenon restricts the IM to attain the rated speed. A detailed study of the SEIG-IM system is made to select proper combination of shunt and series capacitors to avoid the SSR phenomenon.

Generalized State-Space Modeling of Three Phase Self-Excited Induction Generator For Dynamic Characteristics and Analysis

This paper presents the generalized dynamic modeling of self-excited induction generator (SEIG) using state-space approach. The proposed dynamic model consists of induction generator; self-excitation capacitance and load model are expressed in stationary d-q reference frame with the actual saturation curve of the machine. An artificial neural network model is implemented to estimate the machine magnetizing inductance based on the knowledge of magnetizing current. The dynamic performance of SEIG is investigated under no load, with the load, perturbation of load, short circuit at stator terminals, and variation of prime mover speed, variation of capacitance value by considering the effect of main and cross-flux saturation. During voltage buildup the variation in magnetizing inductance is taken into consideration. The performance of SEIG system under various conditions as mentioned above is simulated using MATLAB/SIMULINK and the simulation results demonstrates the feasibility of the proposed system.