Control of current in an inductance with pulse width modulation at control frequency
US7271993B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 27, 2004 |
| Grant date | Sep 18, 2007 |
| Priority date | — |
| Expiry date | Sep 16, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M3/1555
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A PWM controller for a bridge driver circuit for controlling current in an inductive load such as a motor, can set the driver into a forward mode, a slow decay mode or a fast decay mode, and can switch from slow decay mode into forward mode or into fast decay mode for the duration of pulses at controlled time intervals to provide pulse width modulated control of the current. This is a simpler control scheme avoiding complex switching schemes related to mixed mode decay. By using a controlled PWM frequency, it is easier to avoid the problems of variable frequency such as increased heat dissipation or acoustic noise generation. It can have a selector for selecting top or bottom sense switching, enabling a wider range of stable PWM duty-cycles to be used (e.g. 0% to 100%), which is useful to compensate for Back emf influence on coil-drive.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.