State-observer based IDD controller for concurrent frequency-voltage control of a hybrid power system with electric vehicle uncertainties

The present paper proposes a novel state-observer (SO) based integral-double-derivative controller for simultaneous frequency-voltage control operation of a hybrid power system. The hybrid system consists of solar-thermal, conventional-thermal, diesel-plant, and modern day electric vehicle (EV), establishing a concurrent system frequency, voltage, and the corresponding tie-line power control. In order to exhibit realistic approach, the hybrid system is provided with appropriate system non-linearities. For the desired performance of the presented hybrid power system, controller gain parameters are optimized by means of a highly effective magnetotactic-bacteria-optimization (MBO) technique. The objective function to be minimized is such formulated, resulting in optimized system performance. The reduction of objective function values by 13.6% for the proposed controller is exhibited. Similarly, the demerit index shows a reduction of 25% as compared with other controllers. Sensitivity test pertaining to extensive variations of system parameters from the nominal values confirms the robustness of the optimal controller gains. The proposed control strategy is tested on a more complex three-area hybrid power system, and the simulation results further validate the effective regulation approach of the optimal controller with a reduction of 12.9% in objective function value. The fact that EVs assist in improving system stability is also demonstrated. An innovative study related to the effects of large penetration of EVs on the system load demand is presented herewith.