Control apparatus for variably controlling speed induction motor
US6060860A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 18, 1999 |
| Grant date | May 9, 2000 |
| Priority date | — |
| Expiry date | Mar 18, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P21/34
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A control apparatus for variably controlling a speed of an induction motor includes a voltage generator, adders, a rotating speed calculating device, a rotating direction detecting device, and a multiplier. The voltage generator is operated for a predetermined period of time at the start or restart of the induction motor to cause self-excited oscillation in a control system including the voltage generator, the induction motor and the PWM inverter. The rotating speed calculating device obtains the rotating speed data, and the rotating direction detecting device detects the rotating direction of the induction motor based on the .alpha.- and .beta.-axis components, on the stationary coordinate, of the primary current of the induction motor. And, the PWM inverter is started based on the obtained rotating speed data and rotating direction. The control apparatus facilitates starting the PWM inverter that supplies electric power to the induction motor or restarting the PWM inverter after the AC electric power supply to the PWM inverter has recovered from a momentary service interruption.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.