| High-frequency, digitization, miniaturization, green and intelligentization are the current direction of switching power supply development.Green power has become the country's power development request and strategic.Green calls for high power factor, low harmonic pollution, which requires to improve PFC control technology. The current PFC analog control is mature, and is applied in many industrial fileds.With high-speed, low-cost DSP and other digital chips appearance, using digital control in switching power supply has become a trend. Intelligentization calls for stable control and is able to achieve real-time control and automatic management, even remote control which is also closely related to digital control PFC.In this paper, digital control power factor correction technology based on TMS320F28335 DSP is studied.The current PFC control technology and their advantages and disadvantages were analyzed and summarized, which is helpful to selection of PFC control strategy.Analog dual loop control based on UC3854 chip and digital dual loop control based on PI control strategy were analyzed using switch control system and controller design theory in frequency domain, and the current loop, voltage loop design standards and compensation requirements were given.PFC circuit small-signal model was built to obtain the analog controller transfer function.Then the digital controller transfer function was obtained through bilinear changes.A digital simulation PFC model was built using differential equations of PI digital algorithm in MATLAB. Better control results were obtained to verify that the digital controller parameter design is reasonable.A prototype including PFC main circuit board, the signal regulation board, the auxiliary power supply board, etc were designed and implemented.The dual loop PI control strategy using C language was programmed and debuged in CCS3.3 environment.The digital PFC Control was achieved to verify the reaonable of algorithm and simulation results. |
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