Brushless motor drive circuit

Brushless motor drive circuit, if the distributor in accordance with the decision of the distribution ring, to control the motor windings of each phase is turned on or off, so that the motor steps required to drag the rotor magnetic potential of rotation rotation step, the step angle is only two, that the whole or half-step work work, step angle motor structure has been determined. If the request brushless motor with a smaller step angle, higher resolution, or to motor vibration, noise and other reasons, you can switch each input pulse, the only change in the nominal winding corresponding part of the motor synthetic Ci potential step angle rotation only part of the rotor to run each step, only part of the step angle. Here, the winding current is not a square wave, but the step-wave, current rating is the step-input or the removal of the current into the number of steps, the rotor turned on with the same number of times a step away from the corner, this would be a step subdivided into a number of step angle driving method, known as the sub driver. In other countries, for the step system, mainly two-phase hybrid brushless motor and the corresponding sub-driver. However, at home, the majority of users of "niche" is not particularly aware of, but rather that the subdivision is to increase the accuracy, is not the case, mainly to improve the electrical breakdown of the operating performance. As the sub-drive to accurately control the motor phase current, so the drive must have very high technical requirements and process requirements, the cost will be higher.

In order to brushless motor phase current control to achieve the sub-brushless motor step angle of the goal, it was designed for a very wide range of brushless motor drive circuit segments. With the development of micro-computer, especially the emergence of single-chip computer, the breakdown for the brushless motor drive is made easier. Currently, brushless motor drive circuit segments are single-chip computer control of most, they constitute a block diagram shown in Figure 4. Microcontroller according to the requirements of step angle calculated for each phase winding by the current value, and output to digital to analog converter (DPA), by the DPA to digital conversion to the corresponding analog voltage, applied through the phase ring distributor amplifier circuit, amplifier circuit to control each phase winding of the corresponding current to achieve brushless motor breakdown.