An investigation into the effect of photovoltaic module electric properties on maximum power point trajectory with the aim of its alignment with electrolyzer U-I characteristic

Abstract

In order to combine a photovoltaic module and an electrolyzer to produce hydrogen from water, an intermediate DC/DC converter can be used to adapt output power features of the module to input power features of the electrolyzer. This can also be done without using electronics, which results in saving as much as 700 USD/kW, as previous investigation has shown. A more sophisticated investigation should be carried out with the aim of improving high system efficiency, resulting in matching the photovoltaic module maximum power point trajectory (the maximum power point path in the U-I plane as a result of solar irradiance change) to the operating characteristic of the electrolyzer. This paper presents an analysis of the influences of photovoltaic module electric properties, such as series and parallel resistance and non-ideality factor, on the maximum power point trajectory at different levels of solar irradiance. The possibility of various inclinations (right - vertical - left) in relation to an arbitrary chosen operating characteristic of the electrolyzer is also demonstrated. Simulated results are obtained by using Matlab/Simulink simulations of the well known one-diode model. Simulations have been confirmed with experiments on a real photovoltaic module where solar irradiance, solar cell temperature, electric current, and voltage in the circuit with variable ohmic resistance have been measured.

Alkaline Water Electrolysis Powered by Renewable Energy: A Review

“…Otherwise, the cell temperature increases with the absorbed solar radiation. While simple linear approaches already result in a good agreement with experimental data, a complete energy balance is the best way to determine the temperature exactly [29,72]. Table 1.…”

“…Only a short delay is noticeable for the gas purity, which is defined by the system volume [71]. Due to the possibility of direct coupling of water electrolysis and photovoltaic panels, this technology is highly appropriate for renewable hydrogen production [29,72,73]. As photovoltaic panels require high investment costs, wind power is often favored for large-scale hydrogen production.…”

“…Different approaches exist for the calculation of solar photovoltaic power and wind turbine power. While the current-voltage characteristics of photovoltaic panels can be expressed as a function of manufacturer data and solar radiation, the power of wind turbines is a fraction of the maximum available wind power, which is defined by the wind speed and a performance coefficient [72,74].…”

“…A typical current-voltage characteristic of an alkaline water electrolyzer is given by (8). The resulting current of a photovoltaic cell I PV at different solar radiation levels can be described by (10) with a suitable single-diode model as a function of the voltage U PV [29,72,73]. Therefore, specific data from the photovoltaic (PV) panel and the ambient conditions are required in order to calculate the photocurrent I ph , the reverse saturation current I s , and the thermal voltage U T .…”

“…An equation for the thermal voltage is given in (13), which is based on the Boltzmann constant k B (1.3806•10 −23 J K −1 ) and the electron charge e (1.602 19•10 −19 C) [72]. Additionally, the number of serially connected cells, n s , and the cell temperature are required.…”