Electric motor running system employing photovoltaic array
US4999560A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1988 |
| Grant date | Mar 12, 1991 |
| Priority date | — |
| Expiry date | Dec 30, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S323/906
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electric motor running system consists of a photovoltaic array, an inverter for inverting output voltage of the photovoltaic array to AC voltage and automatically controlled so that the frequency is changed in accordance with the output voltage of the photovoltaic array, maintaining the ratio of the voltage to the frequency at a constant value, an induction motor operated by application of the AC voltage from the inverter, and a frequency increasing circuit for increasing the output frequency of the inverter instantaneously so that the motor produces the torque larger than the load starting torque when the motor is started and further decreasing the increased output frequency of the inverter to the normal running frequency after the increased output frequency is maintained for a predetermined period of time. This construction allows the motor to be smoothly started even where a load connected to the motor is a positive displacement pump which has a large static friction torque.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.