Control of three-level quadratic DC-DC boost converters for energy systems using various technique-based MPPT methods.

The conventional DC-DC architecture is often used in photovoltaic systems, with control based on incremental conductance-based maximum power point tracking (MPPT-IC) algorithms. Despite its simplicity and ability to ensure voltage balance across the output capacitors, this architecture suffers several drawbacks. These drawbacks cause undesirable problems such as high power ripples, overshoot, and limited dynamic response. Therefore, this paper proposes a three-level quadratic DC-DC boost converter as a suitable solution to replace conventional inverters in photovoltaic systems, while combined with an advanced MPPT method. The new approach is MPPT based on NARX neural network (NARAX-NN) algorithms. This proposed strategy is designed for high accuracy, robustness, and fast dynamic response compared to the MPPT-IC strategy. In this work, the MPPT-NARX-NN strategy of a three-level quadratic DC-DC boost converter is compared with several different strategies (MPPT-IC, MPPT based on type 1 fuzzy logic (MPPT-T1FL), and MPPT based on type 2 fuzzy logic (MPPT-T2FL)). This comparison is performed using MATLAB under different operating conditions. Simulation results indicate that the MPPT-NARX-NN approach significantly improves the operational performance of a three-level quadratic DC-DC boost converter compared to other strategies, increasing the reliability and deployment of photovoltaic systems. The numerical results show that the MPPT-NARX-NN strategy improves the rise time by 96.43, 97.34, and 94.50% compared to MPPT-IC, MPPT-T1FL, and MPPT-T2FL, respectively. Also, the settling time is improved by 50, 66.66, and 6.66% compared to MPPT-IC, MPPT-T1FL, and MPPT-T2FL, respectively. Furthermore, the strategy increases the average tracking efficiency (%) by 3.86 and 1.12% for MPPT-IC and MPPT-T1FL, respectively. These results highlight the effectiveness of the three-level quadratic DC-DC boost converter based on the MPPT-NARX-NN strategy in extracting energy, increasing performance and flexibility, and improving system reliability, making solar PV systems more efficient and a promising and indispensable solution.