Does Brushless DC Motor Work on DC or AC?

All motors with external characteristics of DC motors that use electronic commutation are collectively referred to as brushless motors. Due to the emergence of brushless DC motors, the strict boundaries between AC-DC speed regulation systems have been broken. In the history of the development of brushless motors, there have been two major structures of brushless motors with great difference, which are brushless DC motors and AC commutated brushless motors.

The electric energy of the bldc motor is finally supplied in DC mode. Based on the method of obtaining DC power, there are two main implementation methods for brushless DC motors: AC-DC-AC control system and DC-AC control system, which are known as square wave.

Using a frequency converter, the AC commutated brushless motor will directly convert 50Hz AC power into AC power, whose frequency changes with the rotor to supply the motor. Its speed regulation characteristic is also similar to bldc motor. At this time, the input of the motor is a positive wave.

In fact, the power supply mode of AC commutation brushless motors is much more complicated than that of brushless DC motors. There are also differences in the later naming. The brushless DC motor has always been used as the original name, while the AC commutated brushless motor is called a permanent magnet synchronous motor.

If the power inverter is integrated in the brushless motor, then the input is DC. So it can still be called a DC motor. However, if the high-power inverter is equipped outside the motor, then the motor is actually supplied by AC power through the inverter. The structure of the BLDC motor is similar to the permanent magnet synchronous AC motor. The difference between them is that the input of the BLDC motor is a square wave, while the input of the permanent magnet synchronous motor is a sine wave.

So the brushless DC motor works on both DC and AC, you can choose according to your needs. Brushless DC motors are widely used in artificial intelligence, automobiles, medical equipment, industrial automation and other industries with long life, low noise, high torque and other characteristics. When the power supply voltage is adjustable, you can select the brushless DC motor whose torque and speed specifications are close to the corresponding rated value of the product, and the required speed can be obtained by changing the voltage. If the supply voltage is fixed, and there is no suitable brushless DC motor to choose from, you can first select it according to the torque, and adjust the product voltage and speed appropriately. The maximum output power of the brushless DC motor is limited. So if the power of the brushless DC motor is selected too small, the motor will be overloaded as the load exceeds the rated output power. If the motor is overloaded, it will generate heat, vibration, speed drop, and abnormal sound. If it is severely overloaded, the brushless DC motor will be burned. However If the power is too large, it will cause economic waste.

Only when you want a motor with strict performance, small volume and high ambient temperature, you can select AlNiCo permanent magnet DC motors or rare earth permanent magnet DC motors is considered. If you need a bldc motor with high torque and low price, ATO can provide you with 1/4 hp brushless DC motor and 400W brushless DC motor, etc.