AN1913 Motorola / Freescale Semiconductor, AN1913 Datasheet - Page 48

• Manufacturer Part Number: AN1913
• Description: AN1913 3-phase BLDC Motor Control with Sensorless Back-EMF ADC Zero Crossing Detection using DSP 56F80x
• Manufacturer: Motorola / Freescale Semiconductor

Software Design
7.3.8 State Diagram - Process Current PI Controller
7.3.9 State Diagram - Process Fault Control
7.3.9.1 PWM Fault A Interrupt Subroutine
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Current Control
The Current PI controller algorithm, controllerPItype1, is described in the SDK documentation. The
controller execution (sampling) period is determined by the PWM module period, since the ADC
conversion is started each PWM reload (once per PWM period). The Current Control Request is set in
ADC Conversion Complete Interrupt.
The process Fault State is described in Interrupt subroutines.
This subroutine is called at PWM A (or PWM in case of DSP56F803) Fault Interrupt.
In this interrupt subroutine, the following faults from the PWM Fault pins are processed:
Request
•
•
PI (Reference Current - Actual Current)
When Overvoltage occurs (the Overvoltage fault pin set)
— DriveFaultStatus |= OVERVOLTAGE
When Overcurrent occurs (the Overcurrent fault pin set)
— DriveFaultStatus |= OVERCURRENT
Figure 7-13. State Diagram - Process Speed PI Controller
U_Desired =
Conversions
Start ADC
BLDC control with BEMF Zero Crossing using ADC
(PWM period)
PWM Reload
Interrupt
Stopped/Starting/Running
Commutation Status
Alignment
Commutation
Set Current Control
Request
Complete Interrupt
ADC Conversion
Current Control
(PWM period)
Disabled
Reset