Conduction mode and three three conduction mode The most common type of brushless motor, electric sequence diagram. Motor each turn a circle, there are six different state, each state has a 60 degrees. Also known as,. Conduction mode. Each state has two phase winding electricity, another set of closed. I am so understand, according to the position of the rotor rotation, different charging state of the switch. As long as according to certain order cycle power up, the rotation of the motor can be kept. To adjust the winding voltage (PWM), which can realize speed regulation. Here in the way of sensorless rotor position detection method. Counter electromotive force (EMF) detection method. Brushless electric motor fan cover dc motor of the counter electromotive force (EMF). The dotted line in the graph, said of the phase counter electromotive force (EMF) of the waveform. 
Counter electromotive force (EMF) and 1/2 motor voltage intersection point, known as ZERO point (ZERO). Can be seen in the figure, the ZERO (ZERO) than the phase Angle is 30 degrees ahead of time. As long as the detection to the ZERO point (ZERO), and then delay 30 degrees, you can know the position of the rotor. As long as ac motor the loop detector ZERO (ZERO), accurate phase, which can realize the rotation of the motor. Due to the first contact to touch, first not further discuss the time delay of 30 small diesel generator degrees, also can say 30 degrees ahead of commutation. The reason is the web site has been successfully by the case. Say again below ZERO (ZERO) detection method. Using the function of three resistance is no matter in which state, motor is negative plate can ensure the comparator input for 1/2 of the motor voltage. The positive input of the comparator, through a multi-channel electronic switch, in different state, switch to a different www.dongfeng-motor.com port. Each state can be detected is zero.
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