AN2528 Freescale Semiconductor / Motorola, AN2528 Datasheet - Page 12

• Manufacturer Part Number: AN2528
• Description: Standard Space Vector Modulation TPU Function Set
• Manufacturer: Freescale Semiconductor / Motorola

AN2528/D
Minimum Pulse Width
12
Phase C
Phase C
Phase A
Phase A
Phase B
Phase B
- bottom
- bottom
- bottom
- bottom
- bottom
- bottom
- top
- top
- top
- top
- top
- top
HSR = 10
HSR = 10
INIT
INIT
Figure 4. svmStd_top and svmStd_bottom state diagram
Standard Space Vector Modulation TPU Function Set (svmStd)
The TPU cannot generate PWM signals with duty cycle ratios very close to 0%
or 100%. The minimum pulse width that the TPU can be guaranteed to correctly
generate is determined by the TPU function itself and by the activity on the
other channels. When the TPU function is requested to generate a narrower
pulse a collision can occur. To prevent this, the parameter MPW (minimum
pulse width) is introduced. The TPU functions svmStd_top and svmStd_bottom
limit the narrowest generated pulse widths to MPW. The CPU program should
check, and limit, the maximum amplitude of the Stator Reference Voltage
Vector before decomposition to u
the Stator Reference Voltage Vector should be less than
If this is not the case, the TPU function will start to limit the minimum pulse
widths to MPW to prevent a collision, and the duty cycle ratio traces will be
deformed as shown on
flag0 = 1
flag0 = 1
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flag0 = 0
flag0 = 0
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Figure
LH_RLD
LH_RLD
1
5.
no reload yet
no reload yet
( 2
á
, u
reload
reload
MPW
â
components. The maximum amplitude of
T
C1234
C1234
HL
HL
DT
LH
LH
3-times
3-times
)
4
4
th
th
-time
-time
LH_C5
LH_C5
HL
HL
MOTOROLA
HSR = 11
HSR = 11
STOP
STOP