Student:	Muhammed Reşit ÇORAPSIZ
Supervisor:	Asst. Prof. Dr. Hakan KAHVECİ
Department:	Elektrik-Elektronik Müh.
Institution:	Graduate School of Natural and Applied Sciences
University:	Karadeniz Technical University Turkey

Title of the Thesis:	REDUCTION OF COMMUTATION TORQUE RIPPLES IN BRUSHLESS DIRECT CURRENT MOTORS
Level:	M.Sc.
Acceptance Date:	18/6/2018
Number of Pages:	133
Registration Number:	i3373

Summary:

In this thesis, it is aimed to reduce the torque ripples occurring during commutation of

phase currents of brushless direct current motors (BLDCM) operating at both low and high

speeds by using direct current (DC) link voltage control technique. This technique is

achieved by placing a DC–DC converter in front of the inverter to obtain the voltage level

required to equalize the slopes of the incoming and outgoing phase currents during

commutation at the maximum level. A mode selector circuit is designed for this operation.

The mode selective circuit was used in the commutation times. Except for commutation time

was used the normal source voltage of the BLDCM. The simulation studies carried out under

different load and different speed conditions. When the simulation results are compared with

those of the traditional BLDCM, it was observed that the torque ripples occurring in

commutation decreased considerably.