| With the wide application of power electronic equipments, the harmonic pollution in the power network is becoming more and more serious, how to reduce the pollution has been an emergent problem. In many countries and regions, the current harmonic caused by power electronic equipments is now strictly limited according to the relevant IEC standards. In order to restrict the current harmonic, power factor correction (PFC) circuit is often used in the electronic equipments. With the fast development of active power factor correction (APFC) technology in recent decades, many new topologies and control strategies have been proposed, a novel control strategy with nonlinear-carrier (NLC) control is implemented recently, and it has caused a major concern, by employing the control strategy, the circuit can extinguish disturbances in one switch cycle.Several familiar topologies of PFC circuits, relevant control strategies of APFC circuits were summarized on the basis of many literatures, the NLC control principle based on boost circuit was discussed in detail. A NLC control strategy with the inductor current sensing was proposed in the thesis. Using the NLC control, a 250W experimental prototype was developed. In advance, both the large signal model and the small signal model for the converter were presented, the transfer function of the open-loop control system was obtained, and all the parameters of the circuit were calculated to meet the design demands. Under the MATLAB environment, the circuit was simulated to verify the parameters.Finally, the prototype was tested, and the relevant experimental waveforms were given. The results revealed that the unity power factor was implemented, the good performance proved the correctness of the NLC control strategy. |
