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Motorola M68HC08 User Manual

Page 35

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BLDC Motor Control

Brushless DC Motor Control Theory

DRM028 — Rev 0

Designer Reference Manual

MOTOROLA

BLDC Motor Control

35

Figure 3-10. Distributed Back-EMF by Unbalanced

Capacity Coupling

Channel 1 in

Figure 3-11

shows the disturbed “branch” voltage, while

the other phase (channel 2) is not affected because it faces balanced
mutual capacitance. The unbalance was purposely made by adding a
small capacitor on the motor terminals, in order to better demonstrate
the effect. After the unbalance was removed the “branch” voltage is
clean, without any spikes.

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Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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