M.Ing. / The induction machine is being widely implemented in motor control systems. Frequently not all the parameters of a system, which consists of an induction machine, an inverter, a load and a controller, are known. As the response of an induction machine is very sensitive to changes in these parameters, it is important to be able to design a control system that is independent of any parameter changes. In the past years, many control techniques have been developed for speed control of machine drives. The use of intelligent controllers has also recently been proposed to improve the response of the induction machine drive. With a fuzzy controller, we will try to eliminate as much as possible the effects of parameter variations that influence the response of the drive system. Since the fuzzy controller design is independent of the dynamic drive system model, the performance of the fuzzy controller is insensitive to any parameter changes. The fuzzy controller replaces the proportional- and integral controller (PI-controller) to determine the slip in a slip controller. The system for which the fuzzy controller is being investigated for implementation, is a battery operated wheelchair using two three phase cage rotor induction machines. These small; low voltage machines show strong parameter variations, making conventional control difficult. The fuzzy logic controller was investigated and the response compared with that of the PI-controller. The results indicated that at high rotor speeds the response of the fuzzy control strategy was favourable, but at low speeds ineffective. By modifying the fuzzy control strategy the rotor speed response can be optimised over the total speed zone.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:9716 |
| Date | 06 September 2012 |
| Creators | Vrey, Coenraad Christoffel Andries |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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