Motor controller incorporating an electronic circuit for protection against inrush currents
US7050278B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 21, 2003 |
| Grant date | May 23, 2006 |
| Priority date | — |
| Expiry date | Jun 5, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H9/005
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Inrush currents in the dc intermediate circuit of a motor controller necessitate the incorporation of protection circuits. These circuits usually take the form of a resistor inserted in series with the intermediate circuit, and the resistor is short-circuited after completion of inrush by a switch positioned in parallel with the resistor. To reduce cable-transmitted electrical noise an earthed noise-decoupling capacitor is added to the intermediate circuit, but it also requires protection against inrush currents. To minimise the number of components, a protection circuit is described which combines noise filtration and inrush protection. According to the invention, the inrush resistor has the form of a resistor network and is connected to a switch which via a controller alters the resistance of the resistor network, so that when the switch is open, the resistance to a differential current is greater than the resistance to a common mode current, and when the switch is closed, there is greater resistance to a common mode current than to the differential current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.