来源：http://www.jnmcd.com 发布时间：2020-07-27 浏览：次
The significant difference between brushless and brushless motors is whether there is a common brush commutator. For the past century, the commutation of Brushless DC motors has been realized by the contact of graphite brush and ring commutator installed on the rotor.
The brushless motor uses the hall sensor to feedback the rotor position back to the control circuit, so that it can know the accurate time of motor phase commutation (sequence). Most brushless motor manufacturers produce motors with three Hall effect position sensors. Because the brushless motor has no brush, there is no relevant interface, so it is cleaner, less acoustic noise, in fact, no maintenance and longer service life.
So, what needs to be further? Although the motor industry is increasingly aware of the advantages of brushless motor, so far, the work is still limited to the development of the above-mentioned BLM Hall sensor control electronic components.
At present, there is an urgent need for the development of motor drive box and motor drive card. They can provide designers with microcontrollers, programmable capabilities and drivers, and integrate all these functions into a single package. Whether in digital or analog mode, it is essentially this integrated way to complete the commutation necessary for various motor applications. Without this integration, the brushless motor will not work.
Pulse width modulation (PWM) IC is gradually being recognized as a preferred technology when selecting the best driver. The choice of the best drive depends only on efficiency. The disadvantages of linear circuit begin to highlight in the middle end, and the output level is about 50%. In this output level, the impedance of the bypass element is equal to the load impedance, which means that the heat generated by the amplifier is equal to the power supplied to the load! In short, when the resistive load is driven at a medium power level, the linear control circuit has a minimum efficiency of 50%.
Compared with the one hundred year old brushless motor, brushless motor is cleaner, smaller and lighter, and is developing steadily and rapidly. For their stable and increasing popularity, it is obviously too conservative to simply summarize them as "it's time".
Just two years ago, brushless motors were far more expensive than brushless motors. However, thanks to the progress of design technology and material technology, its price has dropped sharply. Today, the cost difference between the two motor technologies is only 10%. The most significant change is that designers begin to work closely with industrial applications. Traditionally, this has been considered to be a hard core brush motor application because a "clean" working environment is not the most important. But now, due to the reduction of the cost threshold, brushless motor is getting new applications.
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