Development Of High Frequency Switching Power Supply Used For Aluminum Anodic Oxidation

With the popularity of green energy and environmental protection concept, more and more people are beginning to realize the importance of saving energy. At the same time, accompanied by the advance in power electronics technology, and constantly improve the technology and methods, the new type of high-power high-frequency switching power supply instead of traditional silicon controlled rectifier power supply has gradually become a new trend of development.Now in the aluminum anodic oxidation industry, mostly used SCR power for the oxidation power supply. The SCR oxidation power due to the use of large capacity power frequency transformer, at the same time also need a special filter tank to cooperate in practice, making the huge volume of the equipment, the installation space is large and inefficient. In this paper,the author for the characteristics of the aluminum anodic oxidation power supply low voltage, high current and high power density, targeted to design a new type of frequency 20 KHZ phase-shift full-bridge soft switching oxidation power supply.During the design process, the author compared a variety of soft switching circuit topology structure and selected the phase-shift full-bridge topology structure, then analyzed this topology implementation process of zero voltage soft switching in detail, and found the reasons why the lagging arms switch tubes are hard to achieve zero voltage soft switching. In the control circuit selected, combination the advantages of voltage mode control with the peak current mode control, designed the inner peak current mode and outer average voltage mode double closed-loop based on the phase-shift control special purpose PWM chip UC3879. In the design of high-frequency transformer, selected the toroidal core and open architecture to ensure the transformer heat dissipation effect is good. Ultimately, though continuous improvement and parameters adjustment, the author developed a single module capacity is 44KW, total capacity is 220KW prototype to validated the correctness of theoretical analysis and parameters selection. Based on the prototype of the actual data measured, prototype soft switching waveform is good. Five singles parallel operation, each single flow between modules is effective, and can satisfy the aluminum anodic oxidation process for constant voltage and constant current control requirements. The practical application environment test data show that the new type high frequency soft switching power supply energy saving effect is obvious, than traditional SCR oxidation power saving energy about 15%, effectively reduce the power consumption of aluminum anodic oxidation process, save the production cost for the enterprise. New high-frequency soft switching oxidation power supply overall efficiency around 90%, the output voltage waveform is stable, fully meet the design requirements.