AN1905 ST Microelectronics, Inc., AN1905 Datasheet - Page 63

• Manufacturer Part Number: AN1905
• Description: St7mc Three-phase BLDC Motor Control Software Library
• Manufacturer: ST Microelectronics, Inc.

Figure 45. PWM applied on low/high side on a falling Bemf during demagnetizationf
T1
T1
PWM OFF
PWM ON
A
T0
A
T0
T2-T1 with PWM applied
on high side during demagnetization
I
5
T2
T3
T2
on high side
M
T3
M
ST7MC THREE-PHASE BLDC MOTOR CONTROL SOFTWARE LIBRARY
T4-T1 with PWM applied
Step 4
B
B
HV
I
HV
d
Step 5
I
d
T4
T4
T5
T5
C
C
T1
T2-T1 ->T4-T1
Commutation
T0
A
HV/2
HV
demagnetization current
Σ
0V
4
I
4
I
d
T2
T3
Voltage on
: free wheeling
phase B
B
OR
Demagnetization
HV
Σ
5
T5
t
on low side during demagnetization
T4
C
T4-T1 with PWM applied
T1
T1
T0
A
T0
A
Step 5
I
5
T2
T3
T3
T2
M
M
B
B
HV
HV
I
d
I
PWM OFF
PWM ON
d
T4
T5
T4
T5
C
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