The superiority of brushless DC motors.

The superiority of brushless DC motors.

DC brushless motors have fast response, large starting torque, and the ability to provide rated torque from zero speed to rated speed. However, the advantages of DC motors are also their disadvantages, because in order to generate constant torque under rated load, the armature magnetic field and rotor magnetic field must be maintained at a constant 90 ° angle, which requires the use of carbon brushes and rectifiers. Carbon brushes and rectifiers generate sparks and carbon powder when the motor rotates, which not only causes component damage, but also limits their usage. AC motors do not have carbon brushes or rectifiers, are maintenance free, sturdy, and widely used. However, to achieve performance equivalent to DC motors in terms of characteristics, complex control technology is required. The rapid development of semiconductors nowadays has greatly accelerated the switching frequency of power components, improving the performance of drive motors. The speed of microprocessors is also increasing, which can realize the control of AC motors in a rotating two axis orthogonal coordinate system, and appropriately control the current components of AC motors in both axes, achieving similar performance to DC motor control and comparable to DC motors.

In addition, many microprocessors have incorporated the necessary functions for controlling motors into chips, and their size is becoming smaller and smaller; Like analog/digital converters, pulse width modulation, etc. A brushless DC motor is an application that electronically controls the commutation of an AC motor to achieve characteristics similar to those of a DC motor without any missing components in the DC motor mechanism.