Brushless motors are efficient, stable and durable motors that are widely used in robots, drones, electric vehicles and other fields. Its control principle is to achieve rotation by controlling the interaction between the permanent magnet magnetic field on the motor rotor and the electromagnetic field on the stator.
First, you need to understand the structure of the motor. Brushless motors are composed of permanent magnets and stators. The stator is a coil of copper wire that produces a changing electromagnetic field when energized. A permanent magnet is a magnet with a constant magnetic field. The rotor is composed of a set of magnetic poles and a set of coils. The magnetic poles will continuously change positions as the rotor rotates.
Under normal circumstances, the motor's controller will pass current through the drive circuit to the coil on the rotor to generate a rotating magnetic field. This rotating magnetic field interacts with the magnetic field on the stator to generate torque, which drives the motor to rotate. In a traditional brushed motor, the drive circuit conducts current through the brushes to the rotor. However, there are no brushes in a brushless motor, and the current is controlled by a motor controller.
The main function of the motor controller is to control the current provided by the external power supply to the motor. In a brushless motor, it changes the direction and size of the current flowing through the coil on the rotor according to the control signal, thereby realizing the rotation of the rotor. Specifically, the controller detects the position of the magnetic poles on the rotor and uses these positions to adjust how the coils are energized, directing current into the coils at the optimal time. And this process is completed through the modulator and amplifier on the controller.
In addition to adjusting the direction and magnitude of the current, the brushless motor controller also needs to control the speed and direction of the rotor. In traditional brushed motors, this is usually accomplished via external circuitry. However, in brushless motors, these functions are already integrated into the controller. The controller can adjust the speed and direction of the rotor by changing the way the coils are energized, and it can also use feedback mechanisms to detect and correct errors in the operation of the motor. These feedback signals can come from the rotor position sensor, current detection circuit or other sensors.
In general, the control principle of a brushless motor is to use a controller to control the current provided by the motor's external power supply to achieve the rotation of the rotor. The controller adjusts the direction and magnitude of the current based on the position and speed of the rotor, allowing the motor to run efficiently. This kind of motor has the characteristics of high efficiency, stability and durability, and is widely used in modern industry and technology fields.
