This work investigates the performance of an In \(_{x}\) Ga \(_{(1-x)}\) N-based photovoltaic cell by analyzing the influence of physical and structural parameters such as the indium molar fraction (x), the base thickness (H), and the magnetic field (B) on the solar cell under dynamic frequency illumination. We established a mathematical modeling framework, and simulations show that increasing the indium content initially improves the minority carrier diffusion coefficient, thereby enhancing their transport. The Lorentz effect, induced by the magnetic field, disturbs the carrier trajectories, increases recombination, and leads to a decrease in efficiency. For instance, for \(x = 0.1\) , the efficiency decreases from 26.194 to 25.60 % when B increases from \(4.0 \times 10^{-8}\) to \(3.0 \times 10^{-3}\)  T. Similarly, at constant magnetic field ( \(B = 4.0 \times 10^{-8}\)  T), increasing the indium fraction from 0.1 to 0.3 reduces the efficiency from 26.194 to 21.681%. An optimal base thickness is identified at \(z = H_{opt} = 1.5 \, \upmu \) m, maximizing photocurrent collection. Furthermore, the open-circuit voltage remains stable, while the short-circuit current decreases under the effect of the magnetic field. These results highlight that the joint optimization of indium content, structural parameters, and the electromagnetic environment is crucial to maximize the efficiency of InGaN-based solar cells, particularly for industrial and space applications.