A Brushless motor is currently on the market for most of the hall sensors to sense the position, and then the formula wave controller can be used for normal starting. Of course, as a power switch drive, or need to take into account some current and voltage safety protection, after all, the power device than a simple brush to be delicate, and then further can do some drive on the compensation, according to the working conditions to optimize the drive, to improve some performance. Of course, there are other ways to start the use, according to different needs, using different methods to achieve different results, the following is a brief introduction to several ways to run a brushless motor.
Boosting frequency and voltage synchronous starting method
This method is based on the frequency conversion starting of the synchronous motor, the DSP itself comes with an event manager to generate a PWM waveform to control the inverter, and pull the motor to synchronous at the beginning, while slowly increasing the commutation frequency of the inverter. The stator voltage to the DC brushless motor starts small and gradually increases so that the rotor speed of the DC brushless motor gradually increases so that the brushless motor can achieve similarly. This allows the brushless motor to achieve an open-loop inverter start similar to that of a permanent magnet synchronous motor.
External synchronous three-stage open-loop starting method
The three-stage starting method includes rotor pre-positioning, external synchronous acceleration, and self-synchronization, this starting method is to first arbitrarily conduct two phases of the stator and the other phase is disconnected, through two pre-positioning motors to get the corresponding position. The following is the external synchronization of the rotor, then when the speed of the brushless motor reaches a certain value and switches to self-synchronization, then the position of the brushless motor rotor can be obtained.
Short-time detection pulse rotor positioning start method
Short-time detection pulse rotor positioning starting method is based on the principle that the permanent magnet rotor has a magnetizing and demagnetizing effect on the stator winding with an iron core, thus increasing or decreasing the inductance of the stator winding, the realization of this method can be divided into three processes: pre-positioning, acceleration and switching, but different from the above-mentioned pre-positioning and acceleration methods.
Pre-positioning starting method
This method is to give the stator an actual energized state when the brushless motor is first started, and the rotor rotates to a definite initial position, then the energized state of the motor is changed, and the rotor rotates to the next definite position under the action of electromagnetic torque, and the motor is switched to the brushless motor running state during the rotation process, and the rotor position is detected by the counter-electric potential method.