Control apparatus for AC motors
US4516065A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Sep 7, 1983 |
| Grant date | May 7, 1985 |
| Priority date | — |
| Expiry date | Sep 7, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P2207/05
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
When driving an AC motor with a PWM inverter, the width of a speed command signal is modulated by a carrier to produce width modulated pulses for controlling main switching elements. The width modulated pulses are liable to be attended with impulses which cause magnetic vibrations in the AC motor, resulting in noises. The generation of these impulses can be suppressed by changing the amplification factor of an amplifier for the speed command signal or the amplitude of the carrier on the basis of the rate of change of the speed command signal. Noises which would be attendant on low speed running of the AC motor can be reduced by changing the amplification factor of the amplifier and the amplitude of the carrier on the basis of detected frequency of the speed command signal or revolution of the AC motor during low speed running.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.