Brushless DC (BLDC) motors are becoming more popular in our common daily applications such as HVAC, electric vehicles, whites goods and industrial applications. They help electronic devices to be more reliable and durable. Below is a typical BLDC power supply control system using an 8-bit microcontroller. (Courtesy of Microchip.)
One of the big advantages of using BLDC motors is efficiency, because BLDC motors can rotate continuously at their maximum rotational force (torque). However the brushed motors can provide maximum torque at only certain points in the rotation. Although the brushed motor can deliver the same torque as BLDC motors, the brushed motors require larger magnetics which means that smaller sizes of BLDC motor can deliver considerable power.
Another advantage is controllability. A feedback system can be used to control BLDC motors to deliver the required torque and rotation speed. If BLDC motors are powered by batteries, this precision control can extend battery life because energy consumption and heat loss are minimized .
BLDC motors without the brushes can offer high durability and low electric noise generation. For brushed motors, its brushes and commutators wear out due to continuous moving contact and also generate sparks when contacted. In particular, electric noise is the result of the strong sparks that tend to occur at the area where the brush passes through the gap in the commutator. So BLDC motors are preferable in motor designs where electrical noise is important to avoid.
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