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Detail of mutual inductance effect – Motorola M68HC08 User Manual

Page 33

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BLDC Motor Control

Brushless DC Motor Control Theory

DRM028 — Rev 0

Designer Reference Manual

MOTOROLA

BLDC Motor Control

33

Figure 3-8. Detail of Mutual Inductance Effect

3.2.4.4 Effect of Mutual Phase Capacitance

The negative effect of mutual inductance is not the only one to disturb
the back-EMF sensing. So far, the mutual capacitance of the motor
phase windings was neglected in the motor model, since it affects
neither the phase currents nor the generated torque. Usually the mutual
capacitance is very small. Its influence is only significant during PWM
switching, when the system experiences very high

du/dt.

The effect of the mutual capacitance can be studied using the model
shown in

Figure 3-9

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Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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