Control of oscillator for driving power ultrasonic actuators
US5739724A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 1996 |
| Grant date | Apr 14, 1998 |
| Priority date | — |
| Expiry date | Oct 25, 2016 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB06B1/0253
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
An oscillator supplies a signal of adjustable frequency to drive power ultrasonic actuators. The oscillator frequency is varied and the phase between the voltage and current of the signal is continuously measured. A computer determines the sign of the variation in the absolute value of the phase in the course of successive sampling cycles of predetermined duration and produces therefrom frequency correction signals for the oscillator. A frequency correction is applied to the oscillator in the same direction as the frequency correction applied previously if the variation in absolute value of the phase is negative, and in the opposite direction if the variation in absolute value of the phase is positive. If the variation in absolute value of the phase is zero, a frequency correction of random sign is applied to the oscillator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.