Working Principle of DC Brushless Centrifugal Fans

1. Basic Principle of DC Brushless Motor
The DC brushless motor is the core component of the DC brushless centrifugal fan. Compared with the traditional DC brushed motor, the brushless motor has higher efficiency, lower noise and longer service life. Its basic principle is as follows:
Structural composition: The DC brushless motor is mainly composed of the motor body and the driver. The motor body includes a rotor made of permanent magnetic material, a stator with coil windings and a position sensor. The driver is responsible for receiving the control signal and controlling the operation of the motor according to the signal.
Working Principle: When the motor is powered on, the current in the stator coil generates a magnetic field. This magnetic field interacts with the permanent magnets in the rotor to generate torque, causing the rotor to start rotating. In order to keep the rotor rotating continuously, it is necessary to continuously change the direction of the current in the stator coil, that is, to perform phase commutation. This process is usually completed by an electronic commutator, which accurately controls the timing and sequence of phase commutation according to the rotor position information provided by the position sensor.

2. Working Principle of Centrifugal Fan
A centrifugal fan is a device that uses centrifugal force to throw gas from the center to the periphery. Its working principle is based on the Bernoulli equation and the principle of conservation of momentum in fluid mechanics. When the fan blades rotate, the blades do work on the gas, increasing the pressure and speed of the gas. The gas is thrown to the periphery under the action of the blades to form an airflow. At the same time, due to the negative pressure area caused by the outflow of gas, the external gas will automatically replenish to form a continuous airflow.

3. Working Principle of DC Brushless Centrifugal Fans
Combining a DC brushless motor with a centrifugal fan constitutes a DC brushless centrifugal fan. Its working principle combines the electromagnetic drive of the DC brushless motor and the airflow generation of the centrifugal fan.
Start and accelerate: When the power is turned on, the driver receives the start signal and begins to control the current in the stator coil. Initially, the current is small, the magnetic field generated is weak, and the rotor begins to rotate slowly. As the current gradually increases, the magnetic field increases, and the rotor rotates faster. At the same time, the driver continuously adjusts the timing and sequence of phase change according to the feedback signal of the position sensor to keep the rotor rotating smoothly.
Airflow generation: As the rotor rotates, the centrifugal fan blades also begin to rotate. The blades do work on the gas, increasing the pressure and speed of the gas. The gas is thrown to the periphery under the action of the blades, forming a high-speed airflow. At the same time, due to the negative pressure area caused by the outflow of gas, the external gas will automatically fill in to form a continuous airflow. In this process, the kinetic energy of the gas is converted into potential energy, realizing the transportation and heat dissipation of the gas.
Speed ​​regulation: In order to meet the needs of different occasions, DC brushless centrifugal fans usually have speed regulation functions. This can be achieved by changing the voltage or current supplied to the motor. When the voltage or current changes, the magnetic field strength in the stator coil will also change, affecting the speed of the rotor. By accurately controlling the voltage or current, the fan speed can be accurately adjusted.
Protection and monitoring: In order to ensure the safe and stable operation of the fan, DC brushless centrifugal fans are usually equipped with protection and monitoring functions. For example, overheating protection can prevent the motor from being damaged due to overheating; overcurrent protection can prevent excessive current from causing a short circuit in the circuit; and speed monitoring can monitor the fan speed in real time to ensure that it operates within the set range.

IV. Application and Advantages
DC brushless centrifugal fans have been widely used in various fields due to their advantages such as high efficiency, energy saving, low noise and long life. For example, in the computer field, it is used for CPU cooling fans and chassis fans; in the field of industrial automation, it is used for heat dissipation and gas delivery of various equipment; in the field of new energy vehicles, it is used for heat dissipation of battery packs and gas delivery of air conditioning systems, etc.