Motor speed control circuit having a synchronous PWM signal
US6621242B2 · kind B2 · utility
18Cited by
5References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 1, 2001 |
| Grant date | Sep 16, 2003 |
| Priority date | — |
| Expiry date | Mar 6, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/16
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A motor speed control having synchronous PWM signals has a synchronous phase detecting unit and a PWM control unit. The synchronous phase detecting unit detects the phase variation of a Hall signal, which represents the phase change of the motor, and outputs a digital value to the PWM control unit. The PWM control unit compares the digital value with a speed control command so as to obtain a PWM signal, wherein the PWM signal is synchronized with the Hall signal. Since the PWM signal is synchronized with the Hall signal, the motor is operated smoothly even in the low speed rotation, and audible noises are effectively reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.