Principle of sensorless brushless dc motor control

 motor Lamination ac motor blender parts 
Specifications
1. Lamination of electric motor 
2. IP54 class F 
3. 100% copper 
4. silicon steel stamping 
5.stunning performance 
Main circuit adopts three-phase fully-controlled bridge, as shown in figure 1. By figure 2 we can see clearly in the phase state of dangling (30 ° area before and after passing zero), the winding induction electric potential changes according to the sine law, flat top part is winding electric excitation inverter ac electric motor main circuit voltage phase when clamping. Commutation point occurred in 30 ° after zero, use the back emf method to implement the electronic commutation, is detected in a zero detection circuit after zero 30 ° phase. 6 work mode, three-phase conduction sequence for S1, S2 - S2, S3 - S3, S4 - S4, S5 - S5 and S6 - S6, S1 - S1, S2. There are many electronic commutation method based on the potential, such as "1/2 busbar voltage comparison method", "terminal voltage comparison method" and so on, but these measurements are weak anti-interference ability of problems, especially in the case of PWM modulation, when measuring the special measures must be taken to avoid or suppress interference, increased the complexity of the control circuit, and the phase lag may be produced. Using "virtual neutral point method" can solve the above problem, and in the case of PWM modulation, the switch will not affect phase winding of the zero noise measurement and detection circuit is also relatively motor spare parts simple. 


gost motor 7.5kw

Specifications
1. effiency: IE2 and IE1 
2. 20 years manufacturing experience 
3. 12 months guarantee 

4. low noise and vibtration
Static or low speed in the state of the potential value of 0 or small, can't use the electric potential method to determine the position of the rotor, usually adopts the way of "3-step" start to solve this problem, namely according to his first point type synchronous motor running state began to accelerate from rest, when reaches a certain speed and then switch to the method of back emf control state, including the rotor position, step into the starting switch and free three stages. Rotor position when the first pilot two power tube, usually via the guide S6 and S1, after a certain period of time will finish the initial position of the rotor. Step by step starting from the initial position, by conduction in front of the order, in turn, conduction of each power tube, but the conduction time decreasing according to certain rule, in order to achieve the purpose of speed. Step after starting to switch from the freedom to ensure the correctness of the phase, at the same time, the PWM chopper to gradually add to the main circuit dc voltage, make brushless motor speed electricalmotor1.blogspot.com speeds up, according to the requirements of control of soft starting process of motor speed, thus avoiding the motor at the beginning of the start will produce large current, reduces the impact on the main circuit, prolong the life span of the power tube.