Motorola M68HC08 manual Freescale Semiconductor, Inc

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

BLDC Motor Control

during several commutations, while producing the required torque. Until the back-EMF feedback is locked, the commutation process (explained in Running) assures that commutations are done in advance, so that successive back-EMF zero crossing events are not missed.

After several successive back-EMF zero crossings:

•Exact commutation time can be calculated

•Commutation process is adjusted

•Control flow continues to the Running state

The BLDC motor is then running with regular feedback and the speed controller can be used to control the motor speed by changing the PWM duty cycle value.

Designer Reference Manual		DRM028 — Rev 0
46	BLDC Motor Control	MOTOROLA
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