3-Phase BLDC Motor Control with Sensorless Back EMF ... - Freescale
3-Phase BLDC Motor Control with Sensorless Back EMF ... - Freescale
3-Phase BLDC Motor Control with Sensorless Back EMF ... - Freescale
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
<strong>Control</strong> Technique<br />
No<br />
Commutation Done<br />
B<strong>EMF</strong> Zero Crossing<br />
detected between previous<br />
commutations?<br />
Yes<br />
Service of Commutation:<br />
Preset commutation<br />
Wait for Per_Toff until phase<br />
current decays to zero<br />
B<strong>EMF</strong> Zero Crossing<br />
missed?<br />
No<br />
B<strong>EMF</strong> Zero Crossing<br />
Detected?<br />
No<br />
has commutation<br />
time expired?<br />
Yes<br />
Yes<br />
No<br />
Yes<br />
Make <strong>Motor</strong> Commutation<br />
Corrective Calculation 1.<br />
B<strong>EMF</strong> Zero Crossing missed<br />
Corrective Calculation 2.<br />
corrected setting of<br />
commutation time<br />
Service of received B<strong>EMF</strong><br />
Zero Crossing:<br />
corrected setting of<br />
commutation time<br />
Yes<br />
has commutation<br />
time expired?<br />
Figure 5-7. Flow Chart - <strong>BLDC</strong> Commutation <strong>with</strong> B<strong>EMF</strong> Zero Crossing Sensing<br />
3-<strong>Phase</strong> <strong>BLDC</strong> <strong>Motor</strong> <strong>Control</strong>, Rev. 1<br />
22 <strong>Freescale</strong> Semiconductor<br />
Preliminary<br />
No
Change language