AC Power control circuit
US4358730A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 19, 1981 |
| Grant date | Nov 9, 1982 |
| Priority date | — |
| Expiry date | Jun 19, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M5/2573
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An improved control circuit for accurately regulating the power from a supply of unregulated AC voltage to a load, such as a fan motor, via a signal responsive conduction-control switch. The circuit employs first and second comparators. One input to the first comparator is a DC signal representative of desired power level. The other input of the first comparator is a signal having a DC component and a ripple component. The output of the first comparator is a rectangular waveform having a duty factor which is a function of the desired power level relative to the reference load power level. The first comparator output is integrated and then supplied as an input to the second comparator. A sawtooth signal of constant DC level provides the other input to the second comparator. The sawtooth is a submultiple, or preferably a multiple of the AC supply frequency. The output of the second comparator is another rectangular waveform, the duty factor of which is a function of the DC level of the integrated signal and is used to control the conduction timing of the conduction control switch. Preferably, the combined DC-with ripple-signal input of the first comparator is provided by feedback fro…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.