International Journal of Mobile & Adhoc Network|Vol2|issue 3|August 2012 329 PC based synchronization and speed control of Brushless DC motor G Prasad 1 , M.Venkateswara Reddy 2 , Dr.P.V.N.Prasad 3 , Dr.G.Tulasi Ram Das 4 1 Assistant Professor, Department of Electrical and Electronics Engineering, GITAM University, Visakhapatnam, 530045, Andhra Pradesh, India. 2 Department of Electrical and Electronics Engineering, GITAM University, Visakhapatnam, 530045, Andhra Pradesh, India. 3 Professor, Department of Electrical Engineering, College of Engineering, Osmania University, Hyderabad, Andhra Pradesh, India. 4 Professor, Department of Electrical and Electronics Engineering, College of Engineering, JNTUH, Hyderabad, Andhra Pradesh, India. ABSTRACT The aim of the paper is to control the speed of a Brushless DC motor. For controlling the motor we are connecting the motor to the microcontroller unit. The microcontroller can control the speed of the motor through PWM method. The driver section will be used for driving the motor. The serial connector will be used to communicate between microcontroller and the personal computer. We can control the speed of the motor by using computer also. For this one the serial connection will be connected to microcontroller through Max232. In this project we can control the speed of the motor as per our requirement and the speed of the motor will be displayed in the LCD. The total process can be controlled by microcontroller unit and a personal computer. Key words: personal Computer, Microcontroller, Brushless DC motor, LCD, Max232 1. INTRODUCTION Now a day's every system is automated in order to face new challenges in the present day situation. Automated systems have less manual operations, so that the flexibility, reliabilities are high and accurate. Hence every field prefers automated control systems. Especially in the field of electronics automated systems are doing better performance. The main objective is to control a brushless DC motor. The motor is controlled using the personal computer, which sends the input to the microcontroller which creates respective voltage pulses to control the brushless DC motor. We selected a brushless DC motor because of its performance and low maintenance. When compared to any other motors the losses in a brushless DC motor is less because of the absence of the brushes. Thus the wear and tear of the brushes in the daily use won’t be there in these motors thus the life of these motors is high. The inputs of the motor are given from the personal computer through the software X-CTU to the serial communicator RS232 through USB. The MAX232 converts the input to the microcontroller compatible signals. Thus the microcontroller gives the corresponding output of the given input and which is given to the L293D which gives the input to the motor. The microcontroller program is written in Embedded C. The input voltage is given from the main ac supply which is step down by a step down transformer and then rectified and regulated by regulator. The motor is controlled by pulse width modulation. Different speeds have different Turn on and Turn off time which in controls the speed of the motor accordingly. MICROCONTOLLER (P89V51RD2) The P89V51RD2 is an 80C51 microcontroller with 64 kB Flash and 1024 bytes of data at RAM. A key feature of the P89V51RD2 is its X2 mode option. The design engineer can choose to run the application with the conventional 80C51 clock rate (12 clocks per machine cycle) or select the X2 mode (6 clocks per machine cycle) to achieve twice the throughput at the same clock frequency. Another way to benefit from this feature is to keep the same performance by reducing the clock frequency by half, thus dramatically reducing the EMI. IJMAN Journal homepage: www.ifrsa.org