Active–disturbance–rejection–control and fractional–order–proportional–integral–derivative hybrid control for hydroturbine speed governor system

A novel approach named active–disturbance–rejection–control (ADRC) and fractional–order–proportional–integral–derivative (FOPID) hybrid control scheme is proposed for hydroturbine speed governor system, which is based on ADRC and FOPID control methods. By combining the advantages of ADRC and FOPID controllers, the proposed ADRC–FOPID hybrid control scheme can actively reject the unpredictable disturbance, even with random noises, and can be adapted to the nonlinearities as well as unknown dynamics of hydroturbine speed governor system. The control performances of ADRC–FOPID, ADRC, FOPID as well as conventional proportional–integral–derivative (PID) controllers have been compared. And ADRC–FOPID has been proved to be an effective control scheme for hydroturbine speed governor system.