Dynamic Characteristics and Stability of the Photovoltaic Cell Under Laser Intensity or Load Disturbance in Laser Wireless Power Transmission System.

In laser wireless power transmission (LWPT) system, the dynamically varying laser intensity or load on the photovoltaic (PV) cell may result in significant decrease of the power, efficiency and stability. The explicit steady and dynamic I-V characteristic equations are proposed innovatively to study the dynamic output characteristics and the stability of the PV cell under laser intensity or equivalent load disturbance. The time-domain response equations of photocurrent and dark current under large signal step disturbance are deduced. And the frequency-domain small signal model of the PV cell is derived to calculated the output impedance. The results suggest that the dynamic response time and the steady-state current of the photocurrent increase with the carrier lifetime. The PV cell under the high-frequency disturbance may result in the instability of the LWPT system. The models and methods will provide basis for the simulation and optimization of the DC-DC converter and the closed loop controller to improve the dynamic characteristics and stability of the LWPT system.