Research Information System
Thesis Type: Doctorate
Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2016
Student: EMRE ÇELİK
Supervisor: NİHAT ÖZTÜRK
Abstract:Brushless direct current motor (BLDCM) has been widely used in industry and home appliances for its simple and reliable structure, high power density, and easy controllable feature with low cost. Specific to BLDCMs, commutation current ripple occurring during phase transfer, which is sudden and strong, limits the use of such motors in applications requiring high performance. Although BLDCM control from direct phase current sensing eliminates commutation current ripple at low speed, it still stands as a highly undesired ripple type at high speed. Since commutation current ripple is caused by different current slew rates of commutated phases, it could be eliminated if the slew rates were made equal. Based upon this basic thought, a new reference current generation technique has been put forth in this thesis, where the optimal commutation angle required for the generation of current references is determined adaptively by a fuzzy logic estimator (FLE) rather than mathematical equations. The rule table, which plays a crucial role in the FLE's performance, is determined offline by the genetic algorithms (GAs). To test the performance of the proposed method, simulation and experimental studies are carried out by letting the BLDCM operate by both the traditional method and the proposed method under varying speed and varying control current conditions, and the results are compared with each other. DSP of TMS320F28335 is used in the implementation. According to the simulation and experimental results, it has been seen that the proposed method reduces the commutation current ripple and is less affected by the current controllers' saturation at high speed. The obtained improvements contribute to the motor output power.