Advanced frequency control in isolated microgrids with electric vehicle aggregation: A multi-stage PID controller based on CDM technique under various operating conditions

In this paper, a new multi-stage proportional-integral-derivative (MPID) controller based on the coefficient diagram method (CDM) is proposed to solve the frequency deviation problem in isolated microgrids (MGs) with renewable energy sources (RESs) and plug-in electric vehicle batteries (PHEVs). The MPID controller is implemented with a two-loop proportional-integral (PI) controller and proportional-integral-derivative (PID) structure and uses the CDM method for fine-tuning parameters, improving the dynamic response, stability, and adaptability of the system.Various simulations and comparative evaluations were carried out under different operating conditions, such as load variation and RES disturbances and intermittence, to test the effectiveness and robustness of the proposed method.In contrast to conventional PID tuning approaches, the CDM method dynamically optimizes parameter adaptation, improves system stability, and significantly reduces overshoot and settling time. The results showed that the MPID-CDM controller achieved considerable optimization in terms of performance metrics. These included a 68.40% reduction in integral time absolute error, a 20.7% improvement in settling time, a 58% reduction in overshoot compared to the controller using the standard PID tuned by particle swarm optimization, and a 47% improvement in overshoot compared to the standard PID tuned by cuckoo search algorithms. In addition, integrating PHEVs into the control technique improved frequency regulation by 35% in the case of high load variations, indicating their importance in stabilizing the MG energy management system and improving system efficiency under dynamic and uncertain conditions.