BRUSHLESS MOTOR TORQUE
Today, a growing number of applications rely on a brushless DC (BLDC) motor. These range from medical equipment and home appliances to building controls and industrial automation. In each instance, a BLDC motor is chosen for its numerous advantages, such as:
Avantages:
- There are no sparks
- Potentially cleaner, faster, more efficient, less noisyand more reliable
- Heat is generated in the stator: easier to remove and maintain
- Rotor has permanent magnets vs. coils thus lighter less inertia:easier to start/stop
- Linear torque/current relationship smooth accelerationor constant torque
- Low cost to manufacture
- Simple, low-cost design for fixed-speed applications
- Speed proportionate to line frequency (50 or 60 Hz)
- Complex control for variable speed and torque
- Require electronic control
Conventional DC motors use a stationary magnet with a rotating armature, combining the commutation segments and brushes to provide automatic commutation. In comparison, the brushless DC motor design is a reversed design: the permanent magnet is rotating whereas the windings are part of the stator. These can be energized without a commutator-and-brush system. Even while operating at extremely high speeds, brushless DC motors achieve a long, trouble-free life, as there is no mechanical commutation. The commutation of the brushless DC motor is made electronically and can be done either by looking at the back-EMF of the motor or by using a position sensor.
BLDC MOTOR DESIGN
During the brushless DC motor design phase, DQ Motiontech engineers aim to optimize the brushless motor torque. Motor torque is the amount of rotational force that a motor generates during operation. The key components involved in producing torque are the magnet, the winding and the flux path. The higher the number of pole pairs in the magnet, the higher the amount of brushless motor torque for the same dissipated power. Copper content of the winding contributes to the power provided by the motor while flux path guides all of the magnetic field in the usable channel, minimizing losses. Striking the right balance is important while creating a motor with maximum brushless motor torque that does not draw a tremendous amount of power. Understanding the complete motor design allows DQ Motiontech engineers to pack the most power possible into the smallest motor package.