Fuzzy logic control of an induction generator as a brake

Three fuzzy logic systems (FLS) have been designed to control a self-excited induction generator (SEIG), which is used as a brake. This electrical brake is designed for the sugar cane industry in Queensland, Australia, which uses brake vans coupled to the end of cane trains, to produce a given braking torque. One of the fuzzy logic controllers adjusts the value of a shunt capacitance to maintain the excitation required for the generating operation. The other two adjust the duty cycle of a PWM converter, which drives the load of the induction machine. The duty cycle is adjusted in such a way to keep the retarding torque, produced by the machine, fixed at a given value.