AN1905 ST Microelectronics, Inc., AN1905 Datasheet - Page 59

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

Figure 41. Sampling at f
7.2.3.5 Conclusion
When setting up the system and unless working specifically in Pulse Amplitude Modulation,
the easiest way to start is the ST patented method, providing a fast and effortless solution (no
resistor dividers or RC filters to calculate). If the application requires a true 100% duty cycle (to
bypass the speed limitation while sampling at end of the PWM low state), the sampling has
then to be done during ON time, at PWM or f
7.2.4 Setting the PWM distribution
During each step, one can choose to apply the PWM signal on the low or the high side of the
switches (1 of 3 IGBT/MOSFET legs). Even though this is not mandatory, it can greatly im-
prove the system stability and efficiency.
Changing the PWM distribution can decrease the demagnetization time and can reduce reac-
tive currents in motor windings (see Figures 44,
Phase
voltage
ST7MC THREE-PHASE BLDC MOTOR CONTROL SOFTWARE LIBRARY
SCF
, Pulse Amplitude Modulation
f
SCF
SCF
45
frequency.
& 46).
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