Research On Power Supply Of Semiconductor Laser Based On LCC Resonant Converter

Semiconductor lasers have been concerned widely by researchers at home and abroad because of their advantages such as high conversion efficiency,wide band,small size,and high reliability.Because semiconductor lasers rely on the power supply to inject carriers to work,small fluctuations in input current may cause the output laser changed in wavelength,amplitude,overshoot and other parameters,so the quality of the power supply is critical to its performance.Therefore,it is very valuable to study the power supply of semiconductor laser.Firstly,the specific requirements of the semiconductor laser are determined on the driving power supply by analyzing the working principle of the semiconductor laser.The power supply of semiconductor laser studied in this dissertation works in a quasi-continuous pulse mode,which means that the output current is an approximate rectangular wave and the rising and falling edges of the waveform are as steep as possible and the output current reaches a set value smoothly without overshoot;The output voltage should reach the value corresponding to the rated current in the volt-ampere characteristic of the laser.According to the above two output requirements,the laser power supply designed in this dissertation is mainly divided into two parts: charging and discharging.Secondly,for the pulse discharge process that is the core of the pulse power supply,a scheme that the MOSFET is used in linear working state as the main power switch is proposed in consideration of the pulse power output index of the quasi-continuous operation mode.It means that controlling the gate-source voltage of the MOSFET combined with a closed-loop circuit ensures the output current smooth and stable without overshoot.In addition,in order to improve the output current level of the power supply,a method is adopted,in which the number of MOSFETs connected in parallel is increased in this article;in order to increase the output voltage level of the power supply,another method of cascading multiple discharge module is adopted.The output power of the overall pulsed power supply is increased by the combination of methods.Due to the overall non-linear problem caused by the threshold voltage of the switch MOSFET,acontrol method of micro-current pre-start is proposed in this dissertation,which reduces the oscillation phenomenon when the pulse current rises to a certain extent.Furthermore,the semiconductor laser charging link is divided into two parts.The first part is the PFC(power factor correction)part,which corrects power factor from the grid-side 220 V AC power.This part is mainly implemented by the boost circuit,and its output serves as the bus input voltage of the second part LCC resonant converter topology.By comparing and analyzing the working modes of the LCC circuit,double pulse intermittent mode is determined to be adopted.And the parameters are designed at the maximum constant current output point to achieve an approximate constant current output and provide sufficient energy for the energy storage capacitor.Finally,the theoretical parameters were simulated and verified by simulation software,and the experimental platform with a single-module experimental prototype and a multi-module experimental prototype was built to complete the single-module 44.1kW pulse discharge experiment and the two-module 132.3kW pulse discharge experiments respectively which verifies the theoretical analysis and designed parameters correctness and feasibility.