Research On The Switch Mode Power Supply Controller Of High Power Fast Axial Flow CO₂ Laser

High power fast axial flow (FAF) CO2 lasers are more and more widely used in industrial laser processing applications. Recently, adoption of the high frequency switch mode power supply and the processing controller based on the programmable chip are the trend of the development of laser technology. The developing direction of current laser switch mode power supply is being digital, being intelligentized, being high-frequency and being modularized. So, this project is to develop a power supply controller based on the single chip for the high power fast axial flow CO2 laser. In the system, the microprocessor function and the function of generation of PWM wave are integrated into a piece of chip. In this paper, the operation and primary principle of the FAF CO2 laser control system are analyzed in detail. The theory of the switch mode power supply system is mainly studied. In the design of the power supply, the main circuit topology frame uses half-bridge series resonant switching and parallel load connection, in which, an IGBT is adopted as the power switches, and features high operation frequency, high output power and fast response. In addition, the IGBT in the switch mode power supply has no hard turn-on or turn –off situation in transition, thus the disturbance to the power system is avoided. Especially, the switch mode power supply system can provide the steady discharge current without any ballast. The power supply controller based on the C8051F015 single chip has been developed, which is connected to the laser control system by the RS-232 series interface, and controls the laser operation mode and laser output power. It includes the system initialization, signal inspection, arithmetic design, A/D transformation, the generation and output of PWM wave, etc.. At the same time, the interference source of the single-chip system, which has been taken the corresponding anti-interference measure, has been analyzed. The system is controlled completely in digital mode, which is realized by the software in the chip, so that we can upgrade the system and perfect its function without changing the hardware. At the same time, digital control can bring the advantages of strong anti-disturbance, high dependability, and debug convenience. The experiment result proves that the control system have excellent input-output characteristic, which can achieve the digital control of the switch mode power supply.