Yüksek hızlı fırçasız doğru akım motorlarında moment dalgalanmalarını azaltan bir yöntem

The high speed brushless DC motors (BLDC) have been usually used in the flywheel energy storage systems, the moment control gyroscopes and the industrial applications. These are used in wide speed district. The DC input voltage of inverter is constant in traditional speed control method. In this study, a method based on the boot-buck type DC voltage converter is proposed for the high speed BLDC driver. In this method, the motor current is controlled when the DC link voltage of inverter is adjusted by the boost-buck converter. The winding of the high speed BLDC have too low inductance and resistance. Therefore current control is important problem in the high speed BLDC. The current ripple occurs at different speed values when used in widely speed district. The most important disadvantage of the high speed BLDC is torque ripples which caused by current ripples. High switching frequency is required because of the high fundamental frequency are taken 500 Hz / 1 kHz. dv/dt stresses are seen on the motor winding because of high switching frequency. These voltage stresses must be reduced by using an LC filter. The Corner frequency of the LC filter is taken as 28.2 kHz. The six-step switching technique which applied more easily for microcontroller is chosen to drive motor at high speed region. The hall-effect sensors are used to determine switching sequence. The MOSFET is selected to high switching frequency. In this simulation, PI controller is used to control current and speed. The boost-buck converter based control method was simulated by using MATLAB/SimPowerSystem blocks. The simulation of the high speed BLDC have been performed in the widely speed range by using proposed method. The Switching frequency of the inverter is taken as 50 kHz. The sampling period is taken 20 μs for speed measurement and 10 μs for current measurement. In the simulation, the motor speed was performed at 5000 rpm, 30000 rpm and 60000 rpm. The torque and current waveform of the high speed BLDC was obtained by using proposed method. Waveform shapes of the current and torque were obtained by using proposed method and traditional method. Obtained results were compared by using both method. The ripples of the high speed BLDC phase currents were reduced by using proposed method. Therefore, the amount of the torque ripples have been reduced. Especially, the best result was obtained in low speed. On the other hand, the speed control was performed successfully. Thus, the vibrations of the high speed BLDC was reduced using proposed method. In the future work, the torque ripple of high speed BLDC will be reduced using artificial neural network and fuzzy logic methods in the high speed region