Brushless DC motors are very commonly used now a days. They are everywhere in all equipment used in routine. They are used in computers as cooling fans, hard drive spinning motors and in DVD drives etc. With advent of electric vehicles brushless dc motor use in increased. Brushless dc motor is the best suitable drive motor for many small vehicles drive. Brushless dc motor provides many advantages over regular DC motors and other conventional motors. As these motors have no brushes inside, there are many problems eliminated due to brush removal. Due to brushless design many mechanical problems associated with brushes are also eliminated like friction, maintenance and efficiency problems. As brushed motors have brush and commutator which is worn out component, it could fail catastrophically. In brushless motors the function of the commutator and carbon brush is performed electronically, it is much more reliable and fail proof. As technology has been advance in last few years in rare earth magnets technology and there are very powerful and efficient motors are constructed due to this development which are more powerful and more efficient in same size brushed dc motors.
BLDC Motor running arrangement
Brushless DC motor are run by an electronic controller and the controller supervise all power, voltage and current provides to coils. Also the controller uses PWM to control the speed, power and energy to the motors. These motors could run on both directions from the controller with no difficulties and complexities.
With the advancement in electronics and especially in power electronics, very robust and strong controllers manufacturing is possible. The controllers uses IGBT and Mosfets as output devices which are providing power to the motors. Controllers uses microcontroller with appropriate software to perform all functions required to drive a bldc motor as well as to make necessary pwm signal to power up the bldc motor. There are some special dedicated chips which are used specially to control and run a bldc motor. The very common chip example is FCM8201. This chip has complete detail in its datasheet which shows how to set up the circuit and can make a reliable brushless motor controller.
There is another example of bldc motor controller which is from ON semiconductor MC33033. This chip has complete rotor position circuit integrated inside. So the controller don't need much to run the motor. This chip has capabilty to run 3 phase or 4 phase bldc motors.
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