Research On Symmetrical Voltage-source CPPFC AC/DC Converter

The usage of many power electronic devices pollutes the utility seriously. In order to make the input current satisfy the harmonic standard, we should apply the power factor correction (PFC) technology into the devices.At present, the single-stage PFC technology is one of the focuses in power electronics. Since the late of 1990s, a novel single-stage PFC converter—charge-pump high– power -facter converter was brought up and applied in electronic ballast and AC/DC converters. In this thesis, based on the charge-pump high-power-factor converter, a novel symmetrical voltage-source charge-pump power-factor-correction (VS-CPPFC) AC/DC converter is presented and systemly analyzed and discussed.In the thesis, sysmetrical VS-CPPFC conterver is compared with the diode-clamped VS-CPPFC converter. Firstly, the diode-clamped VS-CPPFC converter's function states and performance are detailed analyzed. To the weakness of the front converter, an improved scheme, sysmetrical VS-CPPFC conterver, is brought up. The function states of the novel scheme are detailed analyzed. And the requisites of high power factor are carried out. Later, the simulation of these two converters are analyzed and compared. The results prove the correctness and feasibility of the improved scheme. Finally, we constructed an experimental device. The main parameters and the choice of parts of the device are introduced. The parts and functions of the control circuit are detailed explained. The experimental waves and datas are given.With the theory analysis, the simulation and the experiment results, the rationality and the feasibility of the sysmetrical VS-CPPFC AC/DC conterver are proved. Compared to tranditional charge-pump circuit, the novel improved converter could enhance the frequency and decrease the volume and weight of the input inductor. The circuit can realize the zero-voltage-switching (ZVS) and decrease the loss of the switch.