What is the principle of brushless motor controller

There are two types of motors used in electric vehicles: brushed motors and brushless motors, which are widely used in electric vehicles due to their low noise and long lifespan. The controller of brushed motors is much more complex and difficult to maintain than that of brushless motors. Therefore, starting from the principle of brushless controller, this article introduces its maintenance points.

The brushless controller for electric vehicles mainly consists of a microcontroller main control circuit, a power transistor front-end drive circuit, an electronic commutator, a Hall signal detection circuit, a relay signal circuit, an undercurrent detection circuit, a current limiting/overcurrent detection circuit, a brake signal circuit, a speed limiting circuit, a power supply circuit, etc.
The fundamental difference between brushless motors and brushed motors is that brushless motors use electronic commutators instead of mechanical commutators in brushed motors, resulting in significant differences in control methods and significantly increased complexity. It is composed of a linear Hall element and a magnet inside. When the rotating handle and magnet move, the Hall element senses a changing magnetic field and outputs a changing voltage. The speed limiting circuit reduces the voltage signal sent to the microcontroller by a voltage divider resistor, thereby limiting the speed.
Working principle: Brushless motors are powered by DC, but they do not continuously provide power to the rotor like brushed motors do. Instead, they provide power to the stator. There are two types of rotors: outer rotor and inner rotor, among which only the stator is charged. Electric motors are divided into Hall induction type and non induction type. The former has its own circuit that changes the magnetic field by altering the rotor position, while the latter requires a specialized controller (electronic governor). Therefore, it is not intuitive to drive the motor directly to work using DC. Brushless DC motor is a typical electromechanical integrated product, consisting of a motor body and a driver. Brushless motor is a type of motor without brushes and commutators, also known as a commutatorless motor. As early as the birth of motors in the 19th century, the practical motor was brushless, that is, AC squirrel cage asynchronous motor, which has been widely used. However, asynchronous motors have many insurmountable defects, which have led to slow development of motor technology.

The main control circuit of the microcontroller is the core part of the brushless motor controller. The Hall signal, handle signal, overcurrent detection signal, and braking signal of the motor are directly input into the microcontroller for processing. The microcontroller outputs the front drive signals of the three bridge arms of the electronic commutator to control the operation of the motor. Therefore, the main control circuit of the microcontroller is the core part of the brushless motor controller.
Today, the editor introduced the content of brushless motors here. If you have any other questions, please feel free to consult us at any time.
2024.7.18  ZG