A Method for MPPT Control While Searching for Parameters Corresponding to Weather Conditions for PV Generation Systems

Abstract

This paper describes a method for maximum power point tracking (MPPT) control while searching for optimal parameters corresponding to weather conditions at that time. The conventional method has problems in that it is impossible to quickly acquire the generation power at the maximum power (MP) point in low solar radiation (irradiation) regions. It is found theoretically and experimentally that the maximum output power and the optimal current, which give this maximum, have a linear relation at a constant temperature. Furthermore, it is also shown that linearity exists between the short-circuit current and the optimal current. MPPT control rules are created based on the findings from solar arrays that can respond at high speeds to variations in irradiation. The proposed MPPT control method sets the output current track on the line that gives the relation between the MP and the optimal current so as to acquire the MP that can be generated at that time by dividing the power and current characteristics into two fields. The method is based on the generated power being a binary function of the output current. Considering the experimental fact that linearity is maintained only at low irradiation below half the maximum irradiation, the proportionality coefficient (voltage coefficient) is compensated for only in regions with more than half the rated optimal current, which correspond to the maximum irradiation. At high irradiation, the voltage coefficient needed to perform the proposed MPPT control is acquired through the hill-climbing method. The effectiveness of the proposed method is verified through experiments under various weather conditions. Index Terms-Current control, irradiation, maximum power point tracking (MPPT), photovoltaic (PV), PV power generation.

Fuzzy Maximum Power Point Tracking Techniques Applied to a Grid-Connected Photovoltaic System

“…Hence, the model of a single cell can be extrapolated to a PV panel model and consequently to a PV panels array interconnected in serial or parallel configuration. The equivalent circuit shown in figure 2, is useful to obtain a model of the PVG to simulate the system under different weather conditions Mutoh et al (2006), Kim et al (2006). From the circuit in figure 2 the output current I is expressed by Mutoh et al (2006): …”

“…-V t = nKT q ; -n is the diode factor (ideality factor (= 1) maximum value 2) Mutoh et al (2006), Kim et al (2006);…”

“…Yafaoui (2009), Hohm & Ropp (2000). The other point, is that the PV generation depends of the weather conditions, such as solar irradiance and temperature Mutoh et al (2006). To ensure the maximum power transfer the load seen from the PV generator must be continuously adjusted.…”

“…Therefore, a Maximum Power Point Tracking (MPPT) algorithm must be implemented to achieve the match between the PV generator (PVG) and the load in real time, taking into account that the maximum power point is not known a priori it is not an easy task to track the maximum power point Mutoh et al (2006) Kim et al (2006), Zeng & Liu (2009). Additionally, regarding the low efficiency of a PVG it would be desirable to obtain the maximum power under any weather condition Mutoh et al (2006), Roman et al (2006). Many MPPT algorithm methods have been proposed to deal with the problem of the power generation variations due to changes at the solar irradiance and at PV cell temperature.…”

Bacterial foraging algorithm based parameter estimation of solar PV model

“…Operating point of solar cells depends on varying factors such as irradiation, temperature, spectral characteristics of sunlight and so on. Environmental conditions like cloudy weather and ambient temperature can change the output power from PV panel [1.2.3.4].. Also the generated power from PV system is non-linear and fluctuates depending on the mentioned factors and do not have constant desirable efficiency [5]. The PV arrays have unique operating point that is capable of delivering the maximum power, which is called the Maximum Power Point (MPP).…”