An analytical technique using the `Newton-Raphson' method is presented to identify the saturated magnetising reactance and the generated frequency of a self-excited induction generator for a given capacitance, speed and load. The technique is shown to be very efficient in analysing such systems under steady state. Computed results are compared with the experimentally obtained values on a laboratory machine, and a reasonable correlation has been observed. Effects of various system parameters on the steady-state performance have been studied, and the results presented provide guidelines for optimum design of such systems.

Analysis of self-excited induction generators

This paper presents the performance of isolated 3-phase self-excited induction generator (SEIG) in micro-hydro power plant using water pump as load. The daily electrical load profile in remote mountainous region of Himalayas shows vast difference in minimum and maximum load on the generator operated in isolated mode. Induction generators are most suitable types of generators for renewable energy conversion systems due to their advantages over conventional generators. The load on these generators has to be kept constant to maintain the voltage and frequency under permissible limits. Therefore under off-load conditions, the extra energy available can be utilized for other purposes such as operating water pump and other need based applications rather than wasting the energy in resistive dump load. In this paper, the potential benefits of using water pump as load under light/off-load conditions have been explored. The performance characteristics of isolated 3-φ SEIG are obtained using MATLAB-Simulink facility and the simulation model is based on the electrical loading pattern in mountainous terrain of Himalayas.

Isolated 3-phase self-excited induction generator in pico-hydro power plant using water pump load in remote mountainous region of Himalayas

This paper presents a power flow model of induction generator for grid connected system. In order to determine the power of induction generator that flow to the electrical distribution system. Parameters of a three-phase squirrel cage induction motor in which obtain from stator, rotor and iron-core are used in characteristic analyzing. There parameters are also employed to establish a mathematical model of the induction generator. The simulation results from the proposed model are compared to the results of the implemented testing set in the laboratory. Then the efficiency of the generators is discussed. From the experimental results, it is found that the model simulation provided power flow results tend to be the same as the testing set with efficiency of 80%. Consequently, it can conclude that the proposed model can be use for induction generator sizing selection.

Power flow and efficiency analysis of three-phase induction generator for grid connected system

Recently, the self-excited induction generators (SEIG) have been widely employed to operate as wind-turbine generators of an isolated power system. This paper proposes a simple method for the steady-state performance characteristics of a SEIG. Unlike the previous method, the proposed method avoids the tedious and erroneous manual work of segregating the real and imaginary components of the complex equation of the model. In this method, the model is formulated in a simple way and then solved using a numerical MATLAB function “fzero”. The effectiveness of this method has been confirmed by comparing on a 0.8-kW induction generator the computed results obtained by the proposed method to those obtained by classical methods.

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A simple method for the steady state performances of self-excited induction generators

This paper presents the experimental evaluation of the performance of 3-φ self-excited induction generator (SEIG) suitable for pico-hydro power generation system feeding domestic load in remote mountainous region. The use of induction generators is most suitable for renewable energy conversion systems due to their enormous advantages over conventional synchronous generators. Important features of induction generators include the simplicity in construction, ruggedness, simplified control, ease in maintenance and small size per generated kW. The performance characteristics of 3-φ SEIG feeding isolated load are evaluated using MATLAB-Simulink model based on the prevalent renewable energy sources inputs and loading conditions in mountainous terrain of Himalayas. The results are validated using an experimental set-up comprising of 3-φ, 3 HP induction motor run as 3- φ induction generator driven by 5HP, 4-pole DC shunt motor acting as prime-mover.

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Experimental Evaluation of Performance of Constant Power Prime-Mover Driven Isolated 3-φ SEIG for Pico-Hydro Power Generation System in Remote Mountainous Region of Himalayas

This paper explains a method to calculate the capacitance value of a 3-O cage induction motor working as a generator in the self-excited mode of operation. The synchronous impedance test method has been reviewed. The capacitance value is determined from the manufacturer data. The effect of voltage variation with different capacitances has been evaluated at constant speed. Performance of self-excited asynchronous generator (SEASG) with the capacitance (calculated value) is evaluated experimentally. Simulation study of the SEASG is done using power system tool box in Mat Lab/Simulink.

Experimental evaluation of capacitance value; to self-excite the induction motor operating as generator in wind energy conversion

This paper describes the simulation based performance study of a 3-O self-excited asynchronous generator (SEASG) in constant power operation. A feed back voltage based controller by using a load control technique to control and retain the generator terminal voltage constant. This technique mostly used in uncontrolled hydro turbine driven induction generators in a stand-alone power generator. The results has been validate by the steady state equivalent circuit analysis of a 2.2kW, 415Volts, 4.7A, Star connected, 1440-rpm induction generator. The proposed study system has been simulated using Mat lab/Simulink version-7.0.The simulated results are presented.

Load control of a 3-ø self- excited asynchronous generator

This paper expound the TRIAC switched capacitor (TSC) based voltage regulation of a 3-O self-excited asynchronous generator (SEASG) fed RL loads. A new self-regulated linear ramp signal based triggering circuit proposed and implemented to switch ON the TRIAC, which includes an external capacitor in the circuit. Steady state equivalent analysis of SEASG has been completed with load and external capacitor. Performance characteristics of SEASG have been simulated using power system toolbox in Mat lab/Simulink software. A prototype model of the triggering circuit has been developed, constructed and tested in the laboratory model of SEASG. The simulated and experimental result presented and discussed.

Voltage regulation of 3-ø self excited asynchronous generator

This paper describes the simulation studies of a 3–0 self-excited asynchronous generator (SEASG) fed RL load in conjunction with an AC/DC/AC converter fed series RLC circuit. An attempt has been made to analyze the current, drawn by the rectifier circuit due to changes in the inverter frequency and their effects on the terminal voltage of the generator have been studied in open loop control. The frequency variation of the inverter fed series RLC circuit emulate the phenomenon of an inductive, capacitive reactance and resistive effect at the point of common coupling (PCC) of the generator terminal. This methodology could be used to inject leading / lagging VAR into the self-excited induction generator network (stand alone power generator), used to extract the power from wind, solar, Mini/Micro hydro energy sources. The proposed system has been simulated using power system tool box in Matlab/Simulink software. An attempt has been made to study the performances of SEASG using simulation. The results have been discussed and also presented.

K. K. Ray

Papers

Experimental evaluation of capacitance value; to self-excite the induction motor operating as generator in wind energy conversion

Load control of a 3-ø self- excited asynchronous generator

Voltage regulation of 3-ø self excited asynchronous generator

Simulation of AC/DC/AC converter fed RLC series circuit with asynchronous generator using Mat lab/Simulink