Module 5 — Controls and machine controllers

Module status: outline

This is the detailed outline for Module 5. The fully written core of the course is Module 1; chapter prose here is in development.

Power apparatus rarely runs open-loop. This module covers the control domain — the block diagrams that sense, compute, and command — and the standard generator controllers that keep voltage and frequency in check: excitation systems / AVRs, governors, and power-system stabilizers.

What you will learn

• How control blocks (gains, summers, integrators, transfer functions, limiters) are discretized and solved alongside the electrical network.
• The signal/IO conventions that let a controller read machine quantities (terminal voltage, field current, speed) and command the machine.
• The structure of an excitation system / AVR, a governor-turbine, and a power-system stabilizer (PSS).
• Why controllers must be initialized to match the machine's steady-state operating point so the system starts in equilibrium.

Planned chapters

• 14. Modeling control systems. Continuous blocks and their discrete equivalents; combining the control solve with the network solve; signal naming and the observables mechanism.
• 15. Excitation systems and AVRs. The standard regulator front-end (voltage error, transducer, regulator, exciter) and representative model types.
• 16. Governors, turbines, and stabilizers. Speed governing and turbine response; the PSS and its damping role; controller auto-initialization from the load-flow operating point.

Hands-on circuits

The control palette includes summers, gains, integrators, PID, transfer functions, signal generators, PWM, and the dq/abc transforms, plus prebuilt generator controllers (excitation, governor, and stabilizer blocks). Worked course samples will pair a synchronous machine with an AVR and a governor and show the closed-loop response to a disturbance. See the component reference for each block's ports and parameters.

Practice themes

Expect problems on: discretizing a first-order lead-lag block; tracing the signal path from a sensed terminal voltage through an AVR to the field; and explaining why a mis-initialized controller produces a start-up transient.

References

• P. Kundur, Power System Stability and Control, McGraw-Hill — excitation systems, governors, and stabilizers.
• IEEE Std 421.5, IEEE Recommended Practice for Excitation System Models for Power System Stability Studies — standard AVR/exciter model structures.
• H. W. Dommel, Electromagnetic Transients Program (EMTP) Theory Book, Bonneville Power Administration — transient analysis of control systems.

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