Direct and indirect flux control of an isolated induction generator

This work presents an excitation control scheme for an induction generator using a PWM VAr compensator. The operation under variable speed conditions typical in wind drivers, the high performance, supported by the field oriented vector control and the total isolated operation, using a starting-up battery are the main features of this system. The vector control is implemented both in a direct field orientation scheme, using a stator flux observer, and in an indirect scheme, based on the voltage vector. In both methods, a DC voltage controller is used to maintain the necessary DC level in the compensator. The analysis is made by the aid of computer simulation and experimental results obtained from a 2 HP prototype