AN1913D Freescale Semiconductor / Motorola, AN1913D Datasheet - Page 44

• Manufacturer Part Number: AN1913D
• Description: 3-phase BLDC Motor Control with Sensorless Back-EMF ADC Zero Crossing Detection using DSP 56F80x
• Manufacturer: Freescale Semiconductor / Motorola

Software Design
7.3.4.3 Commutation Control - Set Running
7.3.4.4 Commutation Control - Set Starting
7.3.4.5 Commutation Control - Set Stop
7.3.4.6 Commutation Control - SetAlignment
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This state serves the transition from the Starting (Back-EMF Acquisition) state to Running state by the
BLDC Zero Crossing algorithms (Section 11.1) according to the following actions:
This state is used to set the start of the motor commutation.
The following actions are performed in this state:
The following actions are performed in this state:
In this state, the BLDC motor is set to the Alignment state, where voltage is put across two motor
phases and a current is set to be at the required value. The following actions are provided in the Set
Alignment state:
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T_Actual = Cmt Timer Counter
Setting new commutation parameters and initialized commutation with bldczcHndlrInit
algorithm
Initialization of computation with the bldczcComputInit algorithm
Commutation initialized to start commutation step and required direction
Two additional motor commutations are prepared (in order to create the starting torque)
setting commutation parameters and commutation handler initialization by
bldczcHndlrInit algorithm
first action from bldczcHndlrInit algorithm (for commutations algorithms) is timed by
Output Compare Timer for Commutation timing control (OC Cmt)
PWM is set according the above prepared motor commutation steps
Zero Crossing is initialized by bldcZCrosInit
Zero Crossing computation is initialized by bldczcComputInit
Zero Crossing is Enabled
PWM output is disabled in order to stop motor rotation and switch off the motor power supply.
PWM set according to Align_Step_Cmt variable status
Current controller is initialized
PWM output is enabled
Aligned Time is timed by Output Compare Timer for Speed and Alignment
bldczcHndlrStop algorithm is called
BLDC control with BEMF Zero Crossing using ADC
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