High-Efficiency Pulse Width Modulation-Based Wireless Laser Power Transmission Step-Down System

Wireless laser power transmission is a promising technique in the far-field wireless power supply with the advantages of high-power density, and small transmitter and receiver sizes. This article proposes a high-efficiency pulse width modulation-based wireless laser power transmission step-down system based on an 808 nm laser diode and gallium arsenide photovoltaic cells. The output voltage of the proposed system is controlled with the use of pulse width modulation of the laser diode in the transmitter without switch tubes and rectifier diodes in the receiver. The model of the proposed system is built, and characteristics of the system is analyzed based on the state-space averaging method. Additionally, the steady and dynamic operations, as well as the efficiency analyses, are investigated and evaluated experimentally. With the use of the propounded system, when the load is 3 ohms and the output voltage is 1.5 V, a converter efficiency of 96.6% is obtained that is ~10% and ~5% higher than those of continuous wireless power transmission constant voltage systems with asynchronous and synchronous buck converters, respectively.