Method and apparatus for independently controlling each phase of a multi-phase step motor
US6879128B2 · kind B2 · utility
9Cited by
8References
10Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 28, 2003 |
| Grant date | Apr 12, 2005 |
| Priority date | — |
| Expiry date | Jul 28, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P8/12
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The current in each phase of a multi-phase step motor is monitored and the excess phase current above the set point current, as required on a cycle-by-cycle PWM basis, is reduced thereby bringing each phase current down to the set point. The PWM frequency is automatically adjusted to maintain a minimum number of PWM edges within a portion of the current waveform. A maximum charge/discharge time is specified as a percentage of the PWM period. These provide an accurate independent current control within each phase of a multiphase step motor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.