Patent · US Active

Relating to driving brushless DC (BLDC) motors

US8212508B2 · kind B2 · utility

12Cited by

21References

9Claims

0Family size

Assignee

MELEXIS NV · BE

Inventors

Christian Paintz · Erfurt, DE
Thomas Freitag · Hamburg, DE
Detlef Klose · Ieper, BE
Enrico Reinhardt · Bad Langensalza, DE

Key dates

Filing date	Sep 10, 2008
Grant date	Jul 3, 2012
Priority date	—
Expiry date	Jan 2, 2031

Classification

Technology area (CPC H)Electricity
CPC primaryH02P2209/11
WIPO fieldElectrical machinery, apparatus, energy
WIPO sectorElectrical engineering

Abstract

In a three phase BLDC motor the rotor position is monitored by detecting the zero crossing points of the induced back EMF signals BEMF_U, BEMF_V, BEMF_W in the phase windings U, V, W. As they are illustrated, the back EMF signals are substantially sinusoidal but they may in other situations be substantially trapezoidal. The three back EMF signals are 120° out of phase with each other. In order to accurately monitor the back EMF in a phase winding, the driving waveform for each phase U, V, W includes an undriven period P close to the expected zero crossing point. The period P can be a preset part of the driving waveform or can be an interruption of the normal driving waveform in response to suitable interrupt signals. In order to determine the zero crossing points of each back EMF signal, two (or more) samples of the back EMF are taken during the undriven period P and used to interpolate the back EMF signal to determine the zero crossing point.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.