Control techniques for power converters in photovoltaic hybrid energy storage system

A cascade current control technique using fuzzy control, proportional-integral-derivative (PID) and hybrid genetic algorithm PID (GA-PID) for bidirectional DC-DC converter used in photovoltaic hybrid energy storage system (PVHESS) is presented. The GA is used for tuning the PID parameters with the objective of minimizing the mean absolute error between desired and actual voltage of the DC bus. Simulation results for all the control techniques for the PVHESS with GA-tuned PID controller exhibit superior performance compared to the PID control without GA. Fuzzy control has the best performance in terms of overshoot among the three control methods as compared to other control but it has steady state of 0.2%. In the meantime, PID control shows great improvement with the PID tuning with the GA optimization with a maximum reduction of overshoot by 4.63% and maximum reduction of settling time of 36s. GA optimization is a good alternative solution to find the optimum PID gain for the operating points. The DC bus is well regulated with the maximum overshoot of 2.29% with fuzzy control and 3.79% with PID-GA control at extreme transient occurred.