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Chapter Two: Motor Controllers and Drivers
end. In BLDC motors, the front end includes filtering capacitors to convert input voltage
to a suitable internal DC voltage. In BLDC motors that use position sensors to identify the
rotor position, the front end also includes inputs for the sensors.
The digital back end includes the following components:
• A microcontroller provides motor starting and control functions. Here, the more
sophisticated the control requirements, the larger the algorithms and the more
processing power you need.
• Pulse width modulation (PWM) circuitry modulates motor speed by regulating the
driving voltage pulse width. The PWM circuitry keeps the output voltage at the rated
voltage irrespective of load.
• Power drivers provide the power necessary to operate the BLDC motor's functions.
BLDC Drivers
BLDC drivers are bridges between the controller and the motor that provide power for the
motor to function. These "power amplifiers" use the low power input from the controller to
produce more current and higher voltages than can be realized using a microcontroller pin.
"Digital control allows
for easy and flexible
implementation of the
control."
Dr. Naveed-ur-Rehman Malik
Motor Drives Engineer,
Dyson
Designers are driving up to three BLDC motors with just one controller.
This is a huge benefit in that you need just one microcontroller unit,
you do not have to deal with serial communication across motors, and
yet you still have the benefits of multiple motors.
Miguel Mendoza
Principal Technical Marketing Manager, Renesas Electronics
