Modelling of Solar PV under Varying Condition with an Improved Incremental Conductance and Integral Regulator

Abstract

The introduction of solar photovoltaic (PV) systems would provide electricity accessibility to rural areas that are far from or have no access to the grid system. Various countries are planning to reduce their emissions from fossil fuel, due to its negative effects, by substituting with renewable energy resources. The use of solar PV systems is expanding globally because of growing energy demands and depleting fossil fuel reserves. Grid integration of the solar system is expected to increase further in the near future. However, the power output of solar PV systems is inherently intermittent, and depends on the irradiance and the temperature operation of the solar cell, resulting in a wide range of defects. Hence, it is vital to extract peak power from the solar panel in all conditions to provide constant power to the load. This paper presents a tracking control method of the peak output power of a solar PV system connected to a DC-DC boost converter using an improved incremental conductance and integral regulator (IC + IR). The research was carried out because the solar PV output is dependent on environmental parameters, such as solar insolation and temperature. Therefore, it is pertinent to forecast the peak power point in outdoor conditions and to operate at that point, so that solar PV can produce the highest output each time it is used. A peak power point strategy that maximizes the output of a solar PV array is proposed. This method establishes the maximum output operation point under the effects of the solar insolation and the module temperature. An automatic converter restoration scheme with block/de-block signal control is proposed to protect the converters from the higher phase current, total capacitor voltage deviation, grid disturbance, and fault current. The proposed scheme also tracks the peak power point (PPP) of the solar array with stable output voltage under varying operating conditions. It reduces the error signal and ripples at the PPP during instantaneous and incremental conductance to zero. In addition, it controls the solar PV system under constantly changing climatic conditions, and thus improves the system efficiency.

Keywords

• solar photovoltaic system
• peak power point tracking
• incremental conductance
• converter restoration
• boost converter