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BACK EMF DETECTION DURING PWM ON TIME BY ST7MC

Figure 9. (A) Rising edge of zero crossing for back EMF detection during on time; (B)

falling edge of zero crossing for back EMF during on time.

Figure 10 demonstrates that the system is able to run at 100% duty cycle, and the zero

crossing happens at the half of the dc bus voltage.

Figure 10. Waveforms for 100% duty cycle operation.

The software needs some modification as well, which is listed in the appendix.

(A)

(B)