Research On High Power And High Voltage Switching Power Supply For Microwave Sintering

Microwave sintering technology is applied to the ceramic industry widely, due to this kind of heating process is much more energy-saving than conventional ways. Working condition of industry microwave magnetron is depends on the stability of the power supply, because the ripple of output voltage directly effects the electric field intensity thereby affecting the level of volatility of microwave energy output, so the quality of power supply determines the entire microwave sintering equipment performance. Based on the current technical condition of consideration,this paper describes and validates a high-power high-voltage switching power supply design for industrial applications magnetron, this power supply uses phase-shifted full-bridge topology, applies DSP as the controller of dual closed-loop negative feedback control strategy, the work of this paper is carried out mainly from the following aspects:1. To achieve high power switching power supply scheme, carried out feasibility analysis, compared the characteristics of several topologies.According to the project needs, chose a soft-switching phase-shifted full-bridge topology, described its working principle and characteristic.2. Completed the design of main circuit, described the hardware structure of three-phase rectifier filter section, phase-shifted full-bridge section and output section respectively. Analyzed the theory basis ofcomponents selection based on the principle, completed the parameter calculation. Completed the digital model of key components and simulated by Pspice, analyzed the simulation results. Provided strong theoretical guidance for project.3. Constructed the dual closed-loop negative feedback control model and simulation analysis. The small signal model analysis of phase-shifted full-bridge circuit has been made, provided theoretical support for the DSP control program. The control strategy passed the verification by Pspice simulation. Calculated the PI control parameters by the mean of small signal analysis, and produced a prototype which is consist of dual output modules in series mode, output voltage and current is 5000 V / 3A,successfully met the design goals.