Performance Analysis of Self Excited Induction Generator Based Stand-Alone Wind Energy Conversion System

The wind energy system is rapidly developing as one of the most favourable renewable energy sources in the present scenario. Due to the constant research in the field of wind energy related technology and generic growth in power electronics system, wind power generation becomes simpler and economical. For low power wind energy system, SEIG is a good choice as a wind power generator. It has lower cost compared to other generator, lower maintenance demands and natural protection against short circuit. The project mainly focuses on the dynamic analysis and modelling of self-excited induction generator used for low power wind energy system. A wind turbine emulator model using torque imitation scheme is developed to drive the IG using MATLAB/Simulink environment. WTE gives the real characteristics as of a wind turbine for better analysis of SEIG under roof. The dynamic performance of SEIG is carried through Simulink and the validation of the Simulink results are established by experiment

Design and implementation of a wind turbine emulator using an induction motor and direct current machine

The study deals with the application details and validation of a wind turbine emulator (WTE) consisting of a user interface, 1.5kW squirrel-cage induction motor (IM) and separately excited direct current machine (DCM). To this end, an induction motor and direct current machine are mechanically coupled to behave like wind turbine. Thus, by controlling the asynchronous motor over wind data, the shaft of the asynchronous motor rotates like the high turbine shaft of the wind turbine and emulates the wind turbine in the laboratory environment. The user interface includes 12 commercial wind turbines with similar characteristics. The user selects the wind data for a day, then selects the wind turbine and operates the system. The system generates reference speed information in accordance with the user's preferences. The WTE calculations are performed on a PC and 32 bit ARM cortex board, both connected on UART. The generated speed information is applied to the frequency converter via the PI control technique and the induction motor is driven according to the reference speed. The purpose of the study is the hardware implementation of a wind energy conversion system for control and online monitoring in a laboratory environment. The system will allow testing various wind data and performing efficiency analyzes at any time and will enable the testing of small-scale power converters for wind power systems

Performance characteristics and reliability assessment of self-excited induction generator for wind power generation

Abstract The paper presents the performance analysis‐based reliability estimation of a self‐excited induction generator (SEIG) using the Monte‐Carlo simulation (MCS) method with data obtained from a self‐excited induction motor operating as a generator. The global acceptance of a SEIG depends on its capability to improve the system's poor voltage regulation and frequency regulation. In the grid‐connected induction generator, the magnetizing current is drawn from the grid, making the grid weak. In contrast, in the SEIG stand‐alone operation, an external capacitor arrangement is implemented to render the reactive power support. This capacitor arrangement is connected across the stator terminals during the stand‐alone configuration of SEIG. The capacitor serves two purposes, which include voltage build‐up and power factor improvement. Therefore, the paper deals with obtaining the minimum capacitor value required for SEIG excitation in isolated mode applications, including stand‐alone wind power generation. The SEIG performance characteristics have been evaluated for different SEIG parameters. The simulation and experimental results are then compared and found satisfactory. Then, SEIG reliability is estimated considering the MCS method utilizing SEIG excitation's failure and success rates during experimental work in the laboratory. Finally, the SEIG reliability evaluation is performed considering different wind speeds

Grid synchronization of a seven-phase wind electric generator using d-q PLL

Abstract: The evolving multiphase induction generators (MPIGs) with more than three phases are receiving prominence in high power generation systems. This paper aims at the development of a comprehensive model of the wind turbine driven seven-phase induction generator (7PIG) along with the necessary power electronic converters and the controller for grid interface. The dynamic model of the system is developed in MATLAB/Simulink (R2015b, The MathWorks, Inc., Natick, MA, USA). A synchronous reference frame phase-locked loop (SRFPLL) system is incorporated for grid synchronization. The modeling aspects are detailed and the system response is observed for various wind velocities. The effectiveness of the seven phase induction generator is demonstrated with the fault tolerant capability and high output power with reduced phase current when compared to the conventional 3-phase wind generation scheme. The response of the PLL is analysed and the results are presented

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 (fminimax, fmincon, fminunc). 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

A survey of innovative technologies increasing the viability of micro-hydropower as a cost effective rural electrification option in South Africa

Published ArticleThe aim of this paper is to provide a survey of different innovative technologies that can be applied to the micro-hydropower system to make it cost effective for rural energy supply. Electrical, mechanical, civil or electronic technologies that can increase the viability of micro-hydropower as a cost-effective energy source for remote and isolated communities in rural South Africa are presented. The motivation behind this study is that there are a significant number of potential sites in South Africa where microhydropower is a viable energy option to provide reliable and low cost energy and where conventional schemes are not appropriate

Evolution of precision agriculture computing towards sustainable oil palm industry

Precision technology elements have not been implemented yet into the sustainable oil palm industry because the knowledge and technology gap. To resolve the gaps, promote sustainability and integrate the technologies, Oil Palm Management System (OPAMS) was introduced. The precision technologies in OPAMS comprises of Geographical Information System (GIS), Global Positioning System (GPS), remote sensing and yield monitoring. A phase by phase System Development Life Cycle (SDLC) methodology was used to generate the said system with feedbacks from oil palm planters as the inputs for OPAMS’s key features. OPAMS ultimately aims to increase the awareness of the industry on the benefits of utilizing technology to improve plantation performances, increase business and environmental sustainability

Modeling and Analysis of a Self Excited Induction Generator Driven by a Wind Turbine

Wind energy is one of the most important and promising source of renewable energy all over the world, mainly because it is considered to be non-polluting and economically viable. At the same time there has been a rapid development of related wind energy technology. However in the last two decades, wind power has been seriously considered to supplement the power generation by fossil fuel and nuclear methods. The control and estimation of wind energy conversion system constitute a vast subject and are more complex than those of dc drives. Induction generators are widely preferable in wind farms because of its brushless construction, robustness, low maintenance requirements and self protection against short circuits. However poor voltage regulation and low power factor are its weaknesses. A large penetration of wind generation into the power system will mean that poor power quality and stability margins cannot be tolerated from wind farms. This paper presents modeling, simulation and transient analysis of three phase self-excited induction generator (SEIG) driven by a wind turbine. Three phase self-excited induction generator is driven by a variable-speed prime mover such as a wind turbine for the clean alternative renewable energy in rural areas. Transients of machine self-excitation under three phase balanced load conditions are simulated using a Matlab/Simulink block diagram for constant, step change in wind speed and random variation in wind speed

A Small-Scale Standalone Wind Energy Conversion System Featuring SCIG, CSI and a Novel Storage Integration Scheme

Small-scale standalone wind turbines provide a very attractive renewable energy source for off-grid remote communities. Taking advantage of variable-speed turbine technology, which requires a partial- or full-scale power converter, and through integrating an energy storage system, smooth and fast power flow control, maximum power point tracking, and a high-quality power is ensured. Due to high reliability and efficiency, permanent magnet synchronous generator seems to be the dominating generator type in gearless wind turbines, employed for off-grid applications. However, wind turbines using geared squirrel-cage induction generator (SCIG) are still widely accepted due to their robustness, simplicity, light weight and low cost. Permanent magnet induction generator, a relatively new induction-based machine, has recently been recognized in the wind energy market as an alternative for permanent magnet synchronous generator. A thorough comparative study, among these three generator types, is conducted in this research in order to enable selection of the most appropriate generator for off-grid wind energy conversion system (WECS), subject to a set of given conditions. The system based on geared SCIG has been shown to be the most appropriate scheme for a small-scale standalone WECS, supplying a remote area. Different topologies of power electronic converters, employed in WECSs, are overviewed. Among the converters considered, current source converter is identified to have a great potential for off-grid wind turbines. Three current-source inverter-based topologies, validated in the literature for on-grid WECS, are compared for off-grid WECS application. Feasibility study and performance evaluation are conducted through analysis and simulation. Among all, the topology composed of three-phase diode bridge rectifier, DC/DC buck converter, and pulse-width-modulated current-source inverter (PWM-CSI) is identified as a simple and low-cost configuration, offering satisfactory performance for a low-power off-grid WECS. A small-scale standalone wind energy conversion system featuring SCIG, CSI and a novel energy storage integration scheme is proposed and a systematic approach for the dc-link inductor design is presented. In developing the overall dynamic model of the proposed wind turbine system, detailed models of the system components are derived. A reduced-order generic load model, that is suitable for both balanced and unbalanced load conditions, is developed and combined with the system components in order to enable steady-state and transient simulations of the overall system. A linear small-signal model of the system is developed around three operating points to investigate stability, controllability, and observability of the system. The eigenvalue analysis of the small-signal model shows that the open-loop system is locally stable around operating points 1 and 3, but not 2. Gramian matrices of the linearized system show that the system is completely controllable at the three operating points and completely observable at operating points 1 and 3, but not 2. The closed-loop control system for the proposed wind turbine system is developed. An effective power management algorithm is employed to maintain the supply-demand power balance through direct control of dc-link current. The generator’s shaft speed is controlled by the buck converter to extract maximum available wind power in normal mode of operation. The excess wind power is dumped when it is not possible to absorb maximum available power by the storage system and the load. The current source inverter is used to control positive- and negative-sequence voltage components separately. The feasibility of the proposed WECS and performance of the control system under variable wind and balanced/unbalanced load conditions are analyzed and demonstrated through simulation. Finally, the proposed WECS is modified by removing the dump load and avoiding the surplus power generation by curtailment of wind power. The operation of the modified system is investigated and verified under variable wind and load conditions

PERFORMANCE ASSESS OF SELF-EXCITED IG DRIVEN BY WIND TURBINE WORKING WITH FC-TCR

This work presented a self-excited induction generator (SEIG) model controlled by an (FC-TCR) fixed capacitor-thyristor control reactor consisting of a large fixed capacitor in parallel with a thyristor controlled reactor in series with the constant inductance. Induction machines were used because they are capable of working at different speeds. The 3-phase IG was driven by the prime mover that represents the wind turbine. Also, constant voltage and frequency were obtained, regardless of the change in velocity, by using proportional integration (PI control) for each of them. This type of generator is used in isolated rural areas far from power transmission lines. The voltage and frequency are analyzed for each wind speed proposed in the model and calculating the required excitation amplitude and torque required to drive the induction generator. Therefore, it is now a key interest to develop an efficient, viable, economic, and controllable induction generator for harnessing energy from renewable sources. The strategy of control was implemented with MATLAB/Simulink