MPPT integrated simulation system for laser wireless power transmission

In the laser wireless power transmission(LWPT), the wavelength, laser power and temperature of the power transfer laser have a significant influence on the output characteristics of the photocell. The maximum power point tracking(MPPT) can solve the power mismatch problem under the influence of the above factors and improve the DC-DC efficiency of the system. In this paper, an integrated simulation system of MPPT was built for LWPT. The comprehensive influence of wavelength, laser power and temperature on the output characteristics of GaAs photocell was coupled. The output characteristics of photocell under various conditions such as power matching, power mismatch and MPPT modulation could be analyzed at the same time. Firstly, the physical laws of photocell under different wavelength, laser power and temperature were studied. When the wavelength increased, the conversion efficiency η_max reached the maximum value of 50% at about 850 nm, and then η_max decreased rapidly because the photon energy was less than the GaAs band gap. Power increased, η_max was basically unchanged, and the maximum power matching resistance R_Lmax decreased. The temperature rised, η_max and R_Lmax decreased continuously. In addition, the output characteristics of the photocell in the case of power mismatch were studied. The conversion efficiency of the photocell decreased to different degrees compared with the power matching. According to the output characteristics of the photocell, the MPPT circuit was designed in the simulation system, and the maximum power tracking was carried out by using the perturb and observation algorithm. After modulation in MPPT system, the photocell can work at the maximum power point of power matching, and the energy utilization rate of photocell can reach 99.93%. The research results have important guiding significance for the practical application of laser energy transmission.