schwang@infell.com
WhatsApp +86 13590495422
WeChat Sch wang
Why do model aircraft motors use BLDC instead of PMSM?
Home > News >Innovate

Why do model aircraft motors use BLDC instead of PMSM?

The problem comes down to the distinction between PMSM and BLDC. The difference between the two, which I've said before in this column, is simple.

Permanent magnet synchronous motors (PMSM) can rotate at a constant speed synchronized with the power supply frequency, regardless of load and line voltage. Therefore, PMSM is ideal for high precision constant speed drives. The speed/torque characteristics of the PMSM are ideal for directly driving high-horsepower, low-speed (rpm) loads.

The magnetization of the permanent magnet of a BLDC motor and its distribution on the rotor are selected so that the waveform of the back electromotive force (the voltage induced in the stator winding due to the rotor motion) is trapezoidal. In this way, a DC voltage with a rectangular waveform can be used to generate a rotating magnetic field with low torque ripple. Because the applied rectangular voltage is easy to generate, for example, any MCU, or C2000 series DSP or even 51 MCU can generate this PWM wave, so the control and drive of the motor is simple. But the position of the rotor must be known at an Angle in order for the applied voltage to align with the back electromotive force. The alignment of the back electromotive force with the commutation action is very important. Only in this way can the motor operate at the highest efficiency as a DC motor. Therefore, BLDC motors are the best choice for low-cost, high-efficiency applications.

Is PMSM inferior to BLDC in terms of control? You can also use FOC (vector control), DTC (Direct torque control) to achieve control effects and performance similar to DC motors, but the cost is really large, the algorithm is really not simple.

Summary: Both are synchronous motors, BLDC power supply, reverse electromotive force trapezoidal wave; PMSM sinusoidal current supply, counterelectromotive force sine wave.

So the question asks: if I now have a motor, how do I determine which is pmsm and which is bldc?

Can it be observed from the performance? Performance is not very accurate, you can first look at the motor driver, the power supply is direct current, or three-phase AC. In one is to look at the waveform of the back electromotive force.


Previous : What is the working principle of brushless DC motor?

Next: It's already gone.

Contact Us

Hello, if you have any further questions, please leave your contact information. Our company will send a professional customer manager to serve you. Thank you for your support and we look forward to cooperation!