AN1914 Freescale Semiconductor / Motorola, AN1914 Datasheet - Page 22

• Manufacturer Part Number: AN1914
• Description: 3-Phase BLDC Motor Control with Sensorless Back EMF Zero Crossing Detection Using DSP56F80x
• Manufacturer: Freescale Semiconductor / Motorola

Control Technique
22
Figure 5-7. Flow Chart - BLDC Commutation with BEMF Zero Crossing Sensing
No
Wait for Per_Toff until phase
detected between previous
Service of Commutation:
current decays to zero
BEMF Zero Crossing
BEMF Zero Crossing
BEMF Zero Crossing
Preset commutation
Commutation Done
has commutation
commutations?
time expired?
DSP56F80x MC PWM Module in Motor Control Applications
Yes
Detected?
missed?
Freescale Semiconductor, Inc.
For More Information On This Product,
No
No
Yes
Make Motor Commutation
Go to: www.freescale.com
Yes
Yes
No
Service of received BEMF
Zero Crossing:
corrected setting of
commutation time
Yes
Corrective Calculation 1.
BEMF Zero Crossing missed
Corrective Calculation 2.
corrected setting of
commutation time
has commutation
time expired?
No