Start-up of sensorless brushless motor

Abstract

Abstract PURPOSE:To effectively start by narrowing a last pulse width when a counterelectromotive force of a stator coil started by inputting a predetermined number of pulses to an exciting pattern generator is waveform-shaped to accelerate a rotor. CONSTITUTION:Pulses from an astable multivibrator 1 are counted by a counter 3, rectangular exciting patterns U-W are generated from a generator 4, and input to a converter 5. Then, it is applied to the stator of a DC motor 8 via a motor driver 7 to control it in an open loop. Thereafter, the counterelectromotive force of the stator is detected by a detector 19, filtered by a filter 9, phase-shifted by a phase shifter 10, amplified by amplifier 11, and input to the converter 5. A speed is detected from the output of the amplifier 11 by a detector 12. If it becomes a predetermined value or more, the constant of the filter 9 is //instructed to be converted by an instruction unit 13, and a mode switching command of a mode switching circuit 5a is instructed by an instruction unit 6. When the counter 3 counts a predetermined number of pulses, it narrows the width of a final pulse to convert it at a high speed of the rotor with high counterelectromotive force. Thus, it is effectively started and smoothly accelerated.

Inventors

• 👤 Yosuke Kawate
• 👤 川手　陽介

Bibliographic Details