Method and apparatus for determining a zero crossing of a phase current of an electronically commutated electrical machine, in particular for determining a rotor position of the electrical machine
US8981693B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 14, 2011 |
| Grant date | Mar 17, 2015 |
| Priority date | — |
| Expiry date | Aug 12, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R19/175
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method for determining a time for a zero crossing of a phase current in a polyphase electrical machine (2). The method including driving a driver circuit (31; 50) for providing phase voltages to operate the electrical machine (2); deactivating a pulse-width-modulated driving by at least one power switch (36, 37; 52, 53), such that no potential is applied to connecting nodes (AI, A2, B1, B2) by the driver circuit (31; 50), at least during a time segment in each cycle of the pulse width modulation; detecting a diode voltage via a freewheeling diode, with which the deactivated power switch (36, 37; 52, 53) has been provided, within the time segment; and fixing the time for the zero crossing of the phase current as the time after which there is no longer a diode voltage present across the freewheeling diode (40; 54) within the time segment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.