Self-excited Cage Induction Generator Research Articles

Enhancing the Performance of Self-excited Wind-driven Cage Induction Generator through Altering the Poles

Objectives: The present research aims at enhancing the performance of the self-excited wind-driven cheap cage induction generators at the different wind speeds employing control technique involving altering the number of poles of the cage generator and adjusting the shunt capacitor. The control aims to maximize the input power captured from the wind, and to improve the generator electrical performance when the generator feeds static loads, and when supplies dynamic induction motor load. Methods: The analysis of the system has been carried out utilizing a complete mathematical model presented for the driving wind-turbine, in addition to developed mathematical models derived from modernistic circuit models for the self-excited induction generator with both static and dynamic loads. A computer simulation has been performed using the models to identify the performance characteristics. Findings: Control protocols for the generator exciting capacitor and the number of magnetic poles have been reached, which governs the generator speed such that the wind turbine blades revolves at speed which is optimally proportional to the wind stream velocity. Consequently, the highest mechanical power is being taken from the wind. At the same time, the built-up voltage could be adjusted around the load rated voltage for static loads through the newly suggested pole-control technique. In case of dynamic induction motor loads, the poles it is found that good performance is possible through controlling the capacitor size only while fixing the number of magnetic poles at the minimum number. Application: The suggested method leads to cheap and efficient utilization of the wind energy in electrical power generation system, especially in the remote isolated places where usage of systems of selfexcited cage induction generators is highly recommended. Keywords: Cage Induction Generator, Pole-amplitude Modulation, Self-excited, Wind Energy

A NEW TECHNIQUE FOR THE ANALYSIS OF SELF EXCITED INDUCTION GENERATOR

ABSTRACT A new technique to compute the performance of self excited cage induction generator (SEIG) is presented. The proposed method for the analysis of SEIG is capable to provide the performance of SEIG in all the steady state operating conditions. The analysis of self excited cage induction generator problem is formulated as multivariable unconstrained nonlinear optimization problem. The impedance of equivalent circuit of the induction machine is taken as an objective function. The frequency and magnetising reactance or frequency and capacitive reactance, are selected as the independent variables depending upon operating conditions of the machine. The variables are allowed to vary only within their known upper and lower practical limits during the optimization process so as to achieve practically acceptable value of these variables. The optimization problem is solved using Rosenbrock's method of rotating coordinates. The developed mathematical model is quite general in nature and can be implemented for...

Voltage regulator for an isolated self-excited cage induction generator

A voltage regulator for a three-phase self-excited cage induction generator (SEIG) is developed for maintaining its terminal voltage constant irrespective of the nature and amount of load. The proposed regulating scheme consists of a fixed-value capacitor bank and saturable core reactors with appropriate feedbacks. This simple static exciter at the induction machine terminals is capable of meeting its reactive power demand and regulating the terminal voltage. The developed regulator is used for a 5 hp, three-phase squirrel cage induction generator and provides inherent voltage regulation at resistive, inductive and motor loads. Extensive tests are carried out to study the steady-state and dynamic performance of the system. The relevant recorded voltage and current waveforms and other test results are given and discussed in detail. The proposed regulator is also compared with a thyristor controlled reactor type of regulator for an SEIG and is found to be superior to the latter in several aspects.

Design optimization of a capacitor self-excited cage induction generator

The design of a self-excited cage induction generator (SEIG) is formulated as a non-linear multivariable optimization problem. A set of nine variables is identified and nine constraints are imposed on the design to meet the desired performance of the machine. A set of objective functions, such as the active material cost, capacitor cost, regulator cost, and the sum of the active material cost and regulator cost, is considered for the design optimization of the SEIG. Each objective function in the design is optimized using Rosenbrock's method of direct search in conjunction with the sequential constrained minimization technique (SUMT). The computed design results for the various objective functions for a 3.7 kW self-excited cage induction generator are presented in tabular form.