Week 06
Cascaded Current-Speed Control
I use my PSIM report and PI calculation file to revisit the DC-motor model, cascaded current-speed loops, and field weakening.
What I connect in this unit
In cascaded control, the inner current loop produces torque and the outer speed loop generates its torque command. Adequate bandwidth separation lets the outer loop treat the inner loop as a nearly immediate actuator; insufficient separation increases loop interaction, overshoot, and oscillation.
Concept map
- Inner and outer loops
- Bandwidth separation
- Torque command
- Loop interaction
Technical anchor
The design order is to close the current loop first and include its closed-loop transfer in the speed plant, keeping current crossover several times higher than speed crossover.
How I review it
Place the torque-command limiter between loops, check that the inner response settles before the outer response dominates, and ensure both integrators do not drive against each other during saturation.
Connection to the full course
Unit 6 of 12. Unit numbers follow the control structure in the saved design files and do not claim attendance weeks.