The Analysis and Modelling of a Self-excited Induction Generator Driven by a Variable Speed Wind Turbine

Thermo-Electrochemical Processes of the Earth’s Degassing Creating Geomagnetic Field and Changing Its Value and Direction (Thermodynamic Approach)

“…Sohre patented riding brushes to control these currents [11]. Our studies of spontaneous self-exciting rotor currents in turbine [12] [13] as well as the results of Kirschner and Moon [14] allowed suggesting the following necessary conditions for its work: the initial or residual critical level of magnetization, fast speed of relative motion and high conductivity of the rotor-stator spontaneous "exciting" circuit [9] [12] [13], existence of the permanent magnets on rotor (stator) of a generator, or formation of a special exciting circuit [14]. The references cited above demonstrate the principal impossibility of the self-excited geodynamo existence because the Earth's interior does not correspond to the known conditions of a self-exciting generator.…”

“…The relatively full analysis of a self-excited induction generator was proposed by Ofualagba and Ubeku [9]. The residual magnetization as a main source of the rotor currents generation was proposed by Sohre and Nippes [10].…”

Development of Vertical Axis Wind Turbines and Solar Power Generation Hybrid System

“…However, modelling and analysis of indication generator excitation by wind turbine variable speed has been approached by various modeler, induction machine has been widely used for various application as a means of converting electrical energy into mechanical energy or vice-versa while many wind powers use induction machine due to their economical factor, reliability and ability to operate with variable speed control system. Although it was noted that induction machine could have drawbacks which required reactive power for excitation, the problem related to current excitation and power generation is well discussed in [13] work.…”

Wind Energy Dynamics of the Separately Excited Induction Generator

“…In this mode of operation, the capacitor bank supplies the reactive power requirement of the load and generator while the real power demand of the terminal load is supplied by the prime mover. These machines are very economical, reliable and are available in the ranges of fractional horse power (FHP) to multi -megawatt capacity (Ofualagba & Ubeku, 2011). Also, unlike synchronous machines, induction machines can operate at variable speeds.…”

“…There is need for gearbox since there should exist a downward to upward conversion at the side of wind turbine in favour of the speed or rotor, which is consequent of the induction machine type; that is whether it squirrel caged or wound rotor type. Ruggedness, simplicity and cheap characterized the choice of squire cage rotors' use in stand-alone schemes as against wound rotor type which is capable of high starting torque yield with the attendant rotor power extraction at the expense of power electronics cost at the rotor (Ofualagba & Ubeku, 2011). An induction motor can operate as a generator in super synchronous speed raised by an overhauling type of load, or by lowering the inverter frequency below the machine speed, when there is a converter-fed machine drive (Tamas & Szekely, 2013).…”