Robust coordinated control of electrolyzer and PSS for stabilization of microgrid based on PID-based mixed H2/H∞ control

In the stand-alone microgrid with hybrid wind, fuel cell (FC) with electrolyzer (EZ) and diesel generations, the intermittent wind power may cause the serious power fluctuation. In addition to the hydrogen production for FC, the EZ can be used to alleviate power fluctuation by an appropriate control of the absorbed power. Nevertheless, the EZ may fail to suppress the power fluctuation due to large disturbances. To enhance the EZ control performance, a power system stabilizer (PSS) which is assumed to be equipped with a diesel generator can be used. This paper proposes the robust coordinated control of EZ and PSS for microgrid stabilization. The structure of power controller of EZ and PSS is a proportional-integral-derivative (PID). To improve the damping performance and robustness of EZ controller and PSS, the PID parameters of both EZ and PSS are simultaneously tuned based on the mixed H2/H∞ control by bee colony optimization. Simulation studies show that the stabilizing performance and robustness of the proposed EZ and PSS are superior to those of the individual device under system uncertainties such as various wind patterns, loading conditions and severe faults.