Single phase to three phase converter capable of variable speed motor operation
US5402053A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1993 |
| Grant date | Mar 28, 1995 |
| Priority date | — |
| Expiry date | Aug 26, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P1/265
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A converter, for providing three phase power to a three phase induction motor from a single phase supply, includes an inverter connected to the single phase input power lines which has two switching devices, and a bi-directional switch connected between one of the single phase input power and one output line to the motor. The other two outputs provided to the motor are a direct connection from the other AC input line and the output of the inverter. In a first or start-up mode of operation, the bi-directional switch and the inverter are controlled to provide currents to the motor which are at a fundamental frequency lower than the single phase AC input frequency to provide controlled start-up of the motor with limited in-rush current. After the motor has started, the converter may be switched to a second mode wherein the bi-directional switch is turned off and the inverter provides single phase power at increasing frequency to the motor to drive the motor up in speed. In a third mode, where the motor is at or near its rated speed, the hi-directional switch and the inverter may be operated to provide power at the rated frequency to the motor, but at variable and controllable voltage …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.