Variable speed controller with improved efficiency of energy transfer for an AC induction motor
US4366429A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 19, 1980 |
| Grant date | Dec 28, 1982 |
| Priority date | — |
| Expiry date | Jun 19, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P27/06
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A variable speed controller for an alternating current induction motor reestablishes the start time for firing pulses and clock pulses in a circuit having a uniform frequency generator generating firing and clock pulses. Feedback from the stator terminals sets an oscillator with a sawtooth type ramp output. Subsequent feedback from the stator terminals are compared with the output of the oscillator in a comparator that establishes a time or phase shift in the generated output having the same frequency, for resetting the firing pulses so that the frequency of current to the stator winding is a function of the relationship between the stator and rotor positions, and of the current amplitude in the stator windings. Adjustment of the circuit parameters reduces the difference between the rotor and stator positions and optimizes stator current to maintain flux balance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.