Method and apparatus for control of current in a motor winding
US4710686A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 4, 1986 |
| Grant date | Dec 1, 1987 |
| Priority date | — |
| Expiry date | Aug 4, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P2205/01
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A current driver circuit for an inductive load, such as a motor winding, provides unidirectional, controlled current through the winding by use of two pulse width modulator switches on opposite sides of the winding or bidirectional current control by use of two pairs of pulse width modulated switches; each pair straddling the winding relative to the power supply. Each pair of switches is modulated in two different modes to control current during two different operating conditions. The first mode of modulation is used for all but rapidly decaying winding current conditions and a second mode provides control for rapidly decaying winding current. In the first mode, unidirectional current to the winding from the power supply is pulse width modulated while the companion switch of the pair is on. In the second mode of operation for rapidly decaying current control, current from the power supply to the winding is shut off by one switch while the companion switch is pulse width modulated to cyclically switch winding, circulating current back through the power supply in the reverse direction to allow rapid decay of the circulating current. In this manner, increased efficiency is obtained wh…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.