Study On Full-Bridge Three-Level LLC Resonant Converter Based On TMS320F2808

In order to reduce the harmonic pollution and improve the power factor, Power Factor Correction is often used in high-power converter applications. However, output DC voltage of the power factor correction circuit is usually more than600V, which makes the selection of the device of the latter DC-DC converters become difficult, while the three-level technology can solve the problem nicely.In this dissertation, the soft-switching is achieved by using the full-bridge three-level LLC resonant converter topology and impove efficiency of the converter. The LLC resonant tank is introduced to full-bridge three-level converter to form full-bridge three-level LLC resonant converter, which has the following advantage:switches sustain only half of the input voltage and realize ZVS capability from zero to full load, rectifier diodes realize ZCS and the voltage stress on rectifier diodes can be minimized to the output voltage, the input current ripple and output filter can reduced, and suitable for high-voltage high-power applications.In this dissertation. DSP processor is selected to control the full-bridge three-level resonant converter. With the development of FPGA. DSP and ARM technology, the digital control has become the trend of high-power DC-DC converter. Digitization has the characteristics of shorter development cycles, more advanced control algorithms, and complex control strategies can be better achieved.Firstly, this dissertation introduces the dissertation background and significance, three level converter research status and research trends. Secondly,15kW full-bridge three-level LLC resonant converter main circuit hardware is designed which is based on analyzing main circuit control strategy and working principle. And then, according to performance requirements of the digital control of microprocessor, this dissertation chooses the TMS320F2808DSP chip as control core. Based on this, hardware and software of control system are designed. Finally, the dissertation develops a15kW full-bridge three-level LLC resonant converter prototype based on TMS320F2808. studies the soft switching and output characteristcs, and analyses the experimental waveforms in detail. Experiments show that theoretical analysis and prototype design of full_bridge three-level LLC resonant converter is correct.