IMPROVING THE ENERGY EFFICIENCY OF SOLAR PHOTOVOLTAIC POWER PLANTS BY MATCHING PV STRINGS WITH MPPT INVERTER PARAMETERS

Abstract

Introduction. The paper investigates how matching PV string parameters with the operating zone of an MPPT inverter affects the energy efficiency of solar photovoltaic power plants. A 10kW plant based on an ASN-10SL Auxsol inverter and a 30kW plant based on a HUAWEI SUN2000-30KTL-M3 inverter were analyzed to compare effective MPPT operation and mismatch effects. The results show that proper matching of the real PV string operating parameters with inverter characteristics can significantly improve actual electricity generation.

Methods and materials. The study focuses on grid-connected solar photovoltaic power plants operating with MPPT inverters. The methodology includes analysis of inverter and PV module datasheet parameters, calculation of string operating voltage, verification of compliance with the MPPT operating range, analysis of daily generation curves, and estimation of potential generation losses. Monitoring data from AuxsolCloud and mini DataWarehouse were used as the empirical basis.

Results. For the 10kW plant, the PV string operating voltage range of 364-392V was found to match the inverter rated input voltage of 380 V, enabling stable maximum power point tracking and daily generation of 70-82 kWh. For the 30kW plant, signs of MPPT mismatch were identified, with potential generation losses of 354.6 kWh, or 23.68%, over the analyzed period; when extrapolated to 245 operating days, this may reach about 8.69 MWh annually.

Conclusion. The energy efficiency of solar photovoltaic power plants depends not only on the installed PV capacity and inverter efficiency, but also on how accurately the real operating voltage of PV strings is matched to the MPPT inverter parameters. Considering the MPPT voltage range, rated PV input voltage, temperature characteristics of modules, and real operating conditions can reduce generation losses and improve the economic performance of PV plants.