Feedforward Fractional Order PID Load Frequency Control of Microgrid Using Harmony Search Algorithm

In this paper, a feedforward factional order PID (FFOPID) control strategy for load frequency control of a microgrid is presented. In the proposed scheme, a feedforward controller is applied in control of the microgrid in islanded operation. In order to use the feedforward controller, the disturbance signal, which is defined as the difference between power of renewable sources and load, is estimated using a disturbance observer. Using the feedforward controller leads to better performance of the system and will reduce different criteria of frequency deviation such as integral of time multiplied squared error (ITSE). The parameters of the proposed FFOPID controller are tuned using the modified harmony search algorithm based on the new defined cost function, which is defined as the summation of the ITSE criterion and magnitude of maximum frequency deviation. Simulation results for an islanded microgrid including wind turbine operating in Manjil wind farm, solar cells, diesel generator and loads are presented to illustrate the capabilities and effectiveness of our proposed control strategy for the microgrids.