Integrating photovoltaic and power converter characteristics for energy extraction study of solar PV systems

Solar photovoltaic (PV) energy is becoming an increasingly important part of the world’s renewable energy. A grid-connected solar PV system consists of solar cells for energy extraction from the sun and power converters for grid interface. In order for effective integration of the solar PV systems with the electric power grid, this paper presents solar PV energy extraction and conversion study by combining the two characteristics together to examine various factors that may affect the design of solar PV systems. The energy extraction characteristics of solar PV cells are examined by considering several practical issues such as series and parallel connections, change of temperatures and irradiance levels, shading of sunlight, and bypassing and blocking diodes. The electrical characteristics of power converters are studied by considering physical system constraints such as rated current and converter linear modulation limits. Then, the two characteristics are analyzed in a joint environment. An open-loop transient simulation using SimPowerSystem is developed to validate the effectiveness of the characteristic study and to further inspect the solar PV system behavior in a transient environment. Extensive simulation study is conducted to investigate performance of solar PV arrays under different conditions.

► Systematic study of MPPT and grid integration control of solar PV systems.
► MPPT of a solar PV system is determined by both PV array and power converters.
► Temperature and solar irradiance affect power converter and PV array integration.
► Optimal control is important for grid-connected dc-ac converter.
► Converter configuration is critical for PV array MPPT under uneven shading condition.