A Nonlinear Control Design for Variable Speed Pumped Storage Power Plants in order to Improve Fault Ride-Through Capability in Motor Mode

In this article، a nonlinear controller is designed for a pumped storage hydropower (PSH) based on doubly fed induction machine (DFIM) in the motor mode. The main controller of a variable speed PSH consists of three separate parts: motor side converter، grid side converter and pump-turbine guide vanes which are designed via stator voltage oriented vector control. Using the power electronics in DFIM-based application can be made the fault ride through issues. In industrial applications، the variable speed PSH uses a hardware protection، i. e. crowbar or dc link brake chopper، in order to maintain the connectivity to the grid during a fault. In this article، however، the motor side controller is modified by an effective input signal to be added to decoupled d-axis inner loop. It is shown that the proposed controller not only eliminates the need of conventional protection، but also improves the transient responses. Furthermore، it is demonstrated using real-time simulation in Matlab/Simulink that the credibility of the proposed controller