Adaptive parameter optimization based on LCL single-phase grid-connected inverter

The control accuracy of traditional Proportion Integration (PI) controllers in LCL single-phase inverter systems are not high, and it is usually difficult to cope with parameter changes. In this paper, an intelligent control algorithm based on the Improved Fruit fly Optimization Algorithm (IFOA) combined with a traditional PI control strategy is proposed to improve the optimization performance of PI controller. Firstly, the control system of the LCL grid-connected inverter is analyzed, and the whole circuit model is designed in Simulink. The script file in MATLAB is used to design the algorithm, and the joint simulation is realized in Simulink simulation. Secondly, the IFOA algorithm is used to adjust the parameters of the PI controller, and the Proportion Integration (PI) control parameter tuning problem is equivalent to the parameter optimization problem in two-dimensional space. Finally, the absolute integral function of time and current error, total harmonic distortion function (THD), and overshoot are used as objective functions to evaluate the convergence of IFOA algorithm. The system step diagram optimized by IFOA-PI controller is compared with the results of PSO-PI, GA-PI, conventional Z-N tuning PI, and traditional FOA-PI respectively. The experimental comparison results show that IFOA-PI controller is superior to other algorithm controllers in the adjustment time, overshoot, and iteration speed of the output signal of the PI controller of the LCL single-phase grid-connected inverter.