SimPowerSystems

Synchronous Machine and Regulators

This case study investigates the application of a multiinput, multioutput nonlinear controller to a system consisting of a hydraulic turbine and a synchronous generator connected to an infinite bus. The complete system is modeled using Power System Blockset and Simulink blocks.

The objective of this case study is to demonstrate the use of the Synchronous Machine block connected to a complex control system implemented with Simulink blocks. The controller is based on a feedback linearization scheme. Its main goals are to control the rotor angle as well as the terminal voltage, to improve the stability properties, and to obtain good dynamic response. Simulation results will show that the nonlinear controller is able to replace the standard linear controllers and give better performance.

Traditionally, stabilization of power systems was ensured by linear regulators such as the automatic voltage regulator (AVR), the speed governor, or the power system stabilizer (PSS). These compensators assume a linearized model of the power system around an operating point.

The demand for improved performance has created the need to operate power systems closer to the limits and therefore well outside the linear domain. Nonlinearities then begin to have a significant effect, especially after important disturbances that lead to a large variation of the operating point.

This case study allows you to step through the design of a nonlinear controller that takes into account all the nonlinearities of the model. The objectives of the controller are to regulate both the terminal voltage and the internal power angle. The control inputs are the field excitation voltage and the gate opening of the turbine.

Speed Regulation Dynamic Performance

Mathematical Model