Review of Literature on Self-Excited Induction Generators and Controllers

Wind energy is one of the most important and promising sources of renewable energy all over the world. Throughout the globe, in the last, three- or four-decades generation of electricity from wind energy has created a wide interest. At the same time, there has been a rapid development of wind energy-related technology. The control and estimation of wind energy conversion systems constitute a vast subject and are more complex than those of dc drives. Induction generators are widely preferable in wind farms because of their brushless construction, robustness, low maintenance requirements, and self-protection against short circuits. Low cost, robustness, and ease of maintenance are attractive features of induction generators. With wind turbine and micro/mini-hydro generators as an alternative energy source, the induction generators are being considered as an alternative choice to well-developed synchronous generators because of their simplicity, ruggedness, little maintenance, price, brushless (in squirrel cage construction), absence of separate dc source, self-protection against severe overloads and short circuits. In isolated systems, squirrel cage induction generators with capacitor excitation, known as self-excited induction generators (SEIGs), are very popular. This paper presents a review of literature related to the present status of research work on self-excited induction generators (SEIG), their terminal voltage control strategies, and over the past years discussing the classification of induction generators, steady-state and transient analysis, voltage control aspects, and parallel operation of SEIG.