Research On Digital Control Based Power Factor Correction Circuit

In recent years, with the development of Digital Signal Processor (DSP) and Field Programmable Gate Array (FPGA), the research on digital control power factor correction became more and more. It is well known that digital control has several advantages compared to analog control. The main advantages of a digital approach over its analog counterpart are: lower sensitivity to changes in the environment such as temperature, supply voltage fluctuation, aging of components, and so on, and the possibility of a lower part count, thus increasing the integration level and improving the reliability as well as reducing assembling costs. Shortened design cycles can also be achieved.The performance of Power Factor Correction (PFC) based on digital control is mainly studied in this thesis, and a high-power PFC experiment prototype is designed. At first the digital average current control strategy and the digital predictive average current control strategy are analyzed and an improved digital control strategy is proposed for the experiment device.In this paper, the detailed design process of inductance and capacitance of the PFC circuit is given and the Power components of PFC circuit such as switch and diode are also been selected. Based on all those above, the simplify small-signal model of PFC circuit is established, and the control parameters of the Voltage loop and Current loop is calculated and verified by simulation with MATLAB.The detailed design process of PFC experimental prototype, including hardware design and software design, is given in this paper. The design of sampling circuits, driving circuits and control chip peripheral circuits are given in hardware design part and flow chart of the software and design of digital PI regulators are also given in software design part. Then, in order to verify the correction of the proposed theory, a prototype based on digital control PFC is debugged and the experiment results verify the feasibility and correctness of the analysis and design.As a part of digital power system, Auxiliary power's efficiency and performance also concern the overall performance of digital power supply. Finally, some researches on a winding clamp circuit which can improve efficiency and cross regulation of the multiple-output Flyback convert are given. This paper gives a new idea that using a special kind transformer bobbin for the winding clamp which can reduce the cost. Experimental results verify the correctness of the theoretical analysis.