Micro-controller based PWM waveform generation for a multiple phase AC machine
US5317248A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Nov 12, 1992 |
| Grant date | May 31, 1994 |
| Priority date | — |
| Expiry date | Nov 12, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M7/53873
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A multi-processor AC motor control system having a timer processor which generates multiple synchronized PWM waveforms while minimizing software latency effects. The timer processor generates a 50% PWM duty cycle sync signal at the PWM frequency, creating a logic level transition (leading edge) in each PWM period. At each such transition, the timer processor interrupts the host processor for the purpose of updating a multi-byte timer data register with PWM on-time data stored in nonvolatile memory as a function of machine position and requested current. A separate timer channel is provided for each PWM waveform to be generated, and the timer processor sets off-to-on and on-to-off transitions of each waveform in accordance with the updated PWM on-time data such that respective off-to-on and on-to-off transitions in each waveform are centered about the leading edges of the sync signal. If the on-time is 0% or 100%, the timer processor overrides the normal instruction set and forces the logic state of the waveforms to a full-off or full-on logic state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.