Design of photovoltaic grid-connected system based on improved particle swarm optimization and Hermite interpolation

Aiming at the situation of local shading and multi-peak output characteristic P-U curve in the practical application of photovoltaic array, a hybrid algorithm is proposed, which uses the "three-step" strategy to quickly and accurately search the global maximum power point. The Hermite interpolation disturbance algorithm is used to select a large step size and search to the vicinity of the maximum power point through a small number of iterations. Then it is switched to the improved particle swarm optimization algorithm to find the maximum power point. When the result converges or reaches the maximum number of iterations, the voltage value near the global extremum point is output. Finally, the Hermite interpolation disturbance algorithm is carried out, and the small step length is selected to quickly and accurately stabilize at the global extremum point. This hybrid algorithm makes up for the shortcomings of a single algorithm. The advantages and disadvantages of particle swarm optimization algorithm and perturbation method complement each other, avoid falling into the local optimal value and reduce the convergence time, improve the speed and accuracy of the system, and evade the energy loss caused by oscillation. Simulink simulation verifies that the proposed hybrid algorithm has better tracking performance and response speed.