Sensorless brushless DC motor starting method

Abstract

The invention discloses a sensorless brushless DC motor starting method. The motor is formed by a stator and a permanent magnet rotor. The starting method comprises steps: pre-positioning is carried out; cyclic acceleration is carried out, voltage U for enabling the rotor to rotate acceleratively is applied to the stator, T2 time is continued, and position signals of the rotor are synchronously detected; when a position signal of a zero crossing point is detected during an operation process, commutation is carried out at once, and a closed-loop acceleration process is carried out; otherwise, voltage U is applied to the stator, T1 time is continued, position signals of the rotor are detected at the same time, when a position signal of a zero crossing point is detected, commutation is carried out at once, a closed-loop acceleration process is carried out, and if no position signal of the zero crossing point is detected, voltage U is increased, and the step is repeated; and closed-loop acceleration is carried out. According to the method provided by the invention, the problem of starting reliability of the sensorless brushless DC motor can be well solved, no starting curve needs to strictly designed, and the ability of adaptation to motor load fluctuation during the starting process can be improved.

Description

technical field [0001] The invention relates to the field of motor control, in particular to a method for starting a DC brushless motor without a position sensor. Background technique [0002] Brushless DC motors are widely used in the field of motor applications because of their energy saving, low noise, compact structure, and long life. Usually, brushless DC motors generally use position sensors to determine the rotor position, but the use of position sensors not only increases the application cost, increases the complexity of the motor production process, but also reduces the system reliability and anti-interference ability. Therefore, no position sensor The control method of DC brushless motor has become a research hotspot. [0003] At present, the common position sensorless control methods of brushless DC motors include back EMF zero-crossing method, freewheeling diode method, back EMF third harmonic method and other methods. Among them, the back EMF zero-crossing met...

AI Technical Summary

Problems solved by technology

When the motor is unloaded, the lagging angle is small and the starting success rate is high, but when the motor load changes greatly, the lagging angle is large, and it is easy to lose steps during the acceleration process, which leads to the failure of the motor starting

Images