Two-phase electronic control of a three-phase induction motor
US5689167A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 24, 1995 |
| Grant date | Nov 18, 1997 |
| Priority date | — |
| Expiry date | Oct 24, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P7/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A circuit for powering a three-phase AC induction motor. The circuit generates a first signal of the form Vdc+A sin (2.pi.ft-0.degree.) and a second signal of the form Vdc+A sin (2.pi.ft-90.degree.) as is done in conventional circuits for powering two-phase AC induction motors. A vector summation circuit is used to create a third signal from the first two signals. The third signal is of the form Vdc+A sin (2.pi.ft+60.degree.). The first signal is input to a first error amplifier along with a first sampled difference signal from the motor. The third signal is input to a second error amplifier along with a second sampled difference signal from the motor. The outputs from each of the first and second amplifiers is input into a first comparator and a second comparator along with a sawtooth waveform to create a first sinusoidally modulated square wave signal and a second sinusoidally modulated square wave signal. The first and second sinusoidally modulated square wave signals are fed to driver circuits which in turn control an H-bridge circuit for powering the motor from a DC bus. Therefore, the invention achieves two-phase control of a three-phase AC induction motor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.