Lasers have a variety of applications, utilizing long-distance wireless power transfer. They have the capacity to refuel distant mobile devices, including manned and unmanned aircraft. Wired transmission is replaced with laser wireless power transmission for indoor power distribution. The primary procedures for these applications include the lasers being emitted by an optical source and then absorbed in a photovoltaic panel to convert them into energy.
Photovoltaic panels can turn solar and other energy sources into electrical energy. However, the conversion efficiency of the photovoltaic panel is lower than that of a single photovoltaic cell, which causes the output power to be lower than anticipated in laser wireless power transfer. Therefore, it is crucial to determine why the output power of the solar panel exposed to laser radiation is low.
Effect of Mismatch in Solar Panels
A laser produces a non-uniform beam with a Gaussian intensity profile. When irradiated by a laser, a solar panel's cells experience various power densities. The output characteristics of each cell are affected by the power density. Hence, these cells generate a mismatch in the solar panel's output. This discrepancy primarily concerns the strength of the incoming laser and the electrical output of the array of photovoltaic cells. This mismatch lowers the solar panel's output power and poses safety threats. For instance, a cell with a low current will ultimately start a fire by producing heat as a load.
Therefore, when lasers are used to light a solar panel, completing a mismatch analysis and simulating photoelectric conversion may serve as the foundation for raising the effectiveness of wireless power transfer through lasers. Therefore, such modeling and analysis are essential to pertinent technological research.
How the Study was Conducted
The laser intensity distribution equation determines that a very tiny region of the laser has a similar uniformity intensity distribution when comparing the light intensities of two adjacent points.
The input non-uniform laser can be divided into several equivalent tiny lasers with various light intensity values. This theory was the foundation for creating the photovoltaic array model under the laser, which was then simulated using MATLAB/Simulink.
The model of the photoelectric receiver exposed to laser radiation was created using the MATLAB/Simulink program, utilizing the photovoltaic model as the fundamental building block. The photoelectric receiver was composed of twelve fundamental units with temperature and illumination as the input parameters for each unit. The temperature of each unit was entered as 25 °C since it is not the subject of this study.
A multi-wavelength experimental platform was created to validate the simulation findings. This platform employed 36 polycrystalline silicon cells measuring 70 mm by 70 mm by 3 mm.
These cells were spliced into a photovoltaic panel of 420 mm by 420 mm, which had a surface area of 0.1764 m2 and was used to receive laser light. Each solar cell in the photovoltaic panel had an open circuit voltage of 0.6 V and a short circuit current of 120 mA. The solar panel's 36 photovoltaic cells were split into nine branches and were linked in parallel to create the overall output of the whole solar panel. The output voltage and current of the solar panel varied when the connections in the above circuit were altered. However, as the comparative experiment only needs to be run with the same circuit connection, the connection between the circuit and output was not covered in great depth in this study.
Significant Findings of the Study
A relatively tiny region was used to compare the light intensity of two nearby laser sites to increase the solar panel's output power. In a very tiny region, the laser has a comparable uniform intensity distribution, according to the calculation's findings. In other words, a non-uniform laser may be split into several tiny, equivalent, uniform spots with varying light intensity values. Based on this idea, the photovoltaic module exposed to laser radiation was created in MATLAB/Simulink.
According to the modeling findings, the input laser is less uniform. It translates to a lower solar panel output than the output laser, which comprises several equivalent tiny light spots with varying light intensities.
A multi-wavelength wireless power transfer through the laser platform was constructed to validate the simulation findings.
The photovoltaic panel was exposed to laser beams with respective wavelengths of 808, 532, and 1030 nm for the experiment, and the resulting voltage and current values were recorded. The measurement's output power, which corresponds to wavelengths of 808 nm > 532 nm > 1030 nm, was 49.536, 9.009, and 6.034 mW, respectively. This value was in excellent accordance with the simulation's output.
Tiefeng He , Guoliang Zheng , Xing Liu, Qingyang Wu, Meng Wang, Can Yang and Zhijian Lv (2022) Analysis and Experiment of Laser Wireless Power Transmission Based on Photovoltaic Panel. Photonics. https://www.mdpi.com/2304-6732/9/10/684/htm