Certain control strategies for three-phase semi-converters for the operation of self-excited induction generators

Abstract

The application of certain firing angle control techniques such as Negative Firing Angle Control, Extinction Angle Control, and Symmetrical Angle Control has been studied for the first time, for the operation of three-phase semi-converters. The input and output voltage and current waveforms and the expressions for the performance quantities 01' the converter, in terms of the respective control angles a, p, and y, have been analytically derived. These results have been confirmed in the simulation of the converter with these control schemes employing MATLAB software tools. The schemes were applied for the control of Self-Excited Induction Generators popularly employed in the renewable energy conversion systems. 1llusb:ative examples of such generator-converter systems, studied both theoretically and experimentally, have been presented for different types of loading patterns. that would be required in practical applications and relative merits of the schemes are discussed. To ensure compactness, reliability and flexibility as closed loop schemes, microcontroller based firing circuits have been developed.

Classification and analysis of operating modes of three-phase semi-converters feeding battery charging loads using Phase Angle Control scheme - A monograph

“…With varying wind speeds, these generators produce variable voltage-variable frequency power output and so some form of power converter is required for obtaining a desired constant dc voltage. Usually, in the analysis of three-phase or single-phase ac to dc converters, a sufficiently large inductance in series with the load is assumed, which results in a constant and continuous dc load current with negligible ripple content [1][2][3][4]. In case, this inductance is not large enough, the current will cease to be constant and different current patterns would occur.…”

Performance predetermination of variable speed wind-driven grid connected SEIGs

“…Certain firing angle control schemes other than the conventional phase angle control (PAC), namely, Negative Firing Angle Control (NFAC), Extinction Angle Control (EAC) and Symmetrical Angle Control (SAC) have been adopted for the semi-converter [12,13].The need for each of these control schemes to accommodate a wide variation in wind speed, has also been brought out with an example. The relevant analytical expressions have been derived for the design of such systems.…”

Wind-Driven SEIGs for Supplying Isolated Loads Employing DSP Based Power Electronic Controllers

“…With the advent of self-commutating devices such as power MOSFETs and IGBTs, a single stage controlled rectifier circuit has been proposed by few authors, eliminating the forced commutating capacitors. Further, it has also been shown that, in maintaining the desired constant voltage at the dc terminals of the rectifier, different control strategies such as symmetrical angle control, extinction angle control and negative firing angle control could be adopted with such power converters, to suit the different ranges of the varying rotor speed [16][17][18] in the wind driven applications.…”