Digital acoustic noise reduction in electric motors driven by switching power amplifiers
US5712539A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Jan 27, 1998 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/14
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A system and method is provided for controlling a brushless DC motor (100), the motor being of the type having a plurality of coils (25, 26, 27) and a switching amplifier coil driving circuit (25A, 26A, 27A) including a plurality of transistors (21, 22, 29, 30, 33, 34). Current application to the plurality of transistors is controlled to obtain, near a commutation point of the motor, a simultaneous rise in current applied to a first of the transistors and a fall in current applied to a second of the transistors. Controlling application of current to the plurality of transistors involves, for each of the transistors, generating a PWM gate drive signal by selectively switching between a nominal PWM signal and a constant signal. The selective switching is in response to a synthesized state signal, the synthesized state signal being generated to alternate variably between the two states in accordance with a desired ramping of current to the first and second transistors. In one embodiment, the control system is employed for a motor used to rotate a reel of a helical scan tape drive.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.