Filter apparatus and method for brushless DC motors
US8796973B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 2012 |
| Grant date | Aug 5, 2014 |
| Priority date | — |
| Expiry date | Oct 5, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/182
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In a multi-phase brushless DC motor, a zero crossing N-bit filter includes a comparator and a phase multiplexer. The phase multiplexer connects each motor phase to each of a positive and a negative input of the comparator, with a switch in each connection to form a switch array. A microprocessor is disposed to operate the switches, and is configured to measure a BEMF for a first phase by opening the switches connecting all other phases to the positive input of the comparator and by opening the switch connecting the first phase being measured to the negative input of said comparator. The comparators output is received by a shift register. The microprocessor is configured to respond to a zero crossing when a majority of bits in the shift register change between high and low.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.