User Manual

Software Design
3-Phase BLDC Motor Control with Sensorless Back-EMF, ADC, Zero Crossing, Rev. 3
48 Freescale Semiconductor
Preliminary
7.3.7 State Diagram - Process Speed PI Controller
Commutation
U_Desired =
PI (Reference Speed - Actual Motor Speed)
Set Speed Control
Request
Commutation
Speed Control
Disabled
Stopped/Alignment/Starting
Running
Speed Control
Timer Interrupt
(PER_SPEED_SAMPLE)
Speed Control
Request
Reset
Figure 7-12. State Diagram - Process Speed PI Controller
The Speed PI controller algorithm controllerPItype1 is described in the SDK documentation. The controller
execution (sampling) period is PER_SPEED_SAMPLE, period of Speed Control Timer Interrupt.