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Deterministic Motor Phasing For Sensorless BLDC Drive

IP.com Disclosure Number: IPCOM000035275D
Original Publication Date: 2005-Jan-20
Included in the Prior Art Database: 2005-Jan-20
Document File: 1 page(s) / 45K

Publishing Venue

IBM

Abstract

A method of allowing phase voltage feedback signal swapping to a motor control ASIC, microprocessor, or DSP is presented without penalty. This is advantageous because it is possible to limit the routing of high power switching signals near feedback networks using this technique.

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Deterministic Motor Phasing For Sensorless BLDC Drive

Since the PWM outputs are digital, and the BEMF phase inputs are analog, they can share pins. This invention provides a robust design solution for ASICs or licensed microcode to implement a feature where by the MDA itself determines which phase corresponds to which analog input. The advantage to this technology is signal integrity.

Since these are low voltage analog signals that must traverse extremely noisy power inverter bridges, it is sometimes desirable to wire them on a single layer above a dedicated analog ground plane without swapping leads on multiple layers.

Basic theory of operation is as follows:

A s s u m e 3 p h a s e s a re p re s e n t a n d 3 fe e d b a c k c o n n e c tio n s a re m a d e

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R e c o rd in p u t th a t c o rre s p o n d s to p h a s e A .

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R e c o rd in p u t th a t c o rre s p o n d s to p h a s e B .

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R e c o rd in p u t th a t c o rre s p o n d s to p h a s e C .

G e n e ra te m a p fo r p h a s e to fe e d b a c k

S ta rt M o to r A p p lic a tio n

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