Research On Power Control Technology Of High Power Laser RF Power Supply

The power control of RF power supply is one of the key technologies of high power RF slab CO₂ laser. Power control circuit of RF power supply systematic has researched in this thesis, which include Pulse Width Modulator, PWM signal amplifying, grid current detection of high power electronic tube.The circuit can realize the output power adjustment of RF slab CO₂ laser and over-current protection on electronic tube grid. The main contents are as follows:(1)The working principle of high power electronic tube RF power supply and its Requirements for power control circuit has been introduce. Pulse Width Modulation circuit has been designed based on processor TMS320F2812. The circuit can generates three kinds of PWM signals which include maintenance mode, continuous mode and pulse mode.(2) The Serial communication interface of RF power modulator has been written. Communication interface between RF power pulse width modulator and PC has been written by VB6.0 development platform and MSComm communication control. Communicating with the modulator via RS-232 through communication interface, the output signal of RF modulator can be controlled when modulator is in the condition of external controlling and PWM parameters can be real-time displayed when modulator is in the condition of internal controlling.(3) The amplifing circuit of RF power pulse width modulation has been designed. According to the requirements of electronic tube grid drive capability, BIMOSFET is used as an amplifier device of the circuit, whose function is to transfer 5V PWM signal from RF Pulse Width Modulator into -200V PWM signal to drive the grid of tube.(4) The RF power detection circuit for gate current has been designed. The logic function of grid current detection circuit of RF power is completed by using EPM7064SL44 chip. Its main function is to detect the current signal of RF power grid and the power-off signal of circuit. When the average value of gate current is greater than 2.5A or the circuit board is power-down, the CPLD chip would produce a high level alarm signal. Timing simulation for this logic circuit is done by using Quartus2 software.The power control circuit of RF power supply realize the output power real-time control of RF slab CO₂ Laser and guarantee that the RF power tube can work safely and effectively within the rated range.This research provides a theoretical basis and design guidance for the caprure of high power Laser RF power supply and its modulator technology.