Three phase brushless DC motor analysis and drive circuit

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Dokuz Eylül Üniversitesi, Fen Bilimleri Enstitüsü, Elektrik ve Elektronik Mühendisliği Ana Bilim Dalı, Türkiye

Tezin Onay Tarihi: 2003

Tezin Dili: İngilizce

Öğrenci: CENK CENGİZ

Danışman: EYUP AKPINAR

Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu

Özet:

II ABSTRACT In this thesis, to analyze brushless DC (BLDC) motor, a computer simulation program and an implemented circuit are used and the results are compared. Features, structures, torque profile and torque/speed characteristics of BLDC motor are explained, then the mathematical model motor are obtained. Motor parameters are measured, which are necessary for simulation program. In simulation program, 3-phase six-step bridge inverter having 6 MOSFETs has fed the BLDC motor at 120-degree conduction mode. By using the direct back emf detection the correct commutation sequence is selected. In implemented circuit, 8 poles BLDC motor is connected TDA5142T Brushless DC Motor Drive Circuit of Philips. The BLDC motor has been fed by 3-phase six- step bridge inverter having 6 MOSFETs. Sensorless control is used. Back emf comparator detects the zero crossings in the motor back emf and they are used to calculate the correct moment for the next commutation. Closed loop control is applied to the computer simulation program. For the speed control, PI controller is used. The coefficients of PI controller are determined. The PWM is only applied to the high side MOSFETs for the detection of the zero crossing events. The control principal of simulation is to obtain maximum efficiency from the motor by keeping the phase current in phase with the back emf in the same winding. The phase current is limited to 20 A at the starting. Keywords: Brushless DC motor, sensorless control, closed loop control