Study On Single Phase Power Factor Correction Converter With Active Floating Charge Landing

With the development of the power electric technology, more and more power electrical equipments are used in different fields. The harmonic pollution in power systems caused by power converter has been taken a great consideration. The common method to solve this problem is to use power factor correction (PFC), and Boost converter is usually applied as the pre-regulator of the two-stage PFC converter to get a unit power factor, because of its advantages such as smaller input current distortion, high efficiency and regulating the input current through controlling the inductor current directly. Due to its step-up voltage conversion ration, the output voltage is higher than the peak value of the input voltage. When the input voltage is 220V (AC), the output will be 400V (DC), that means a high switching losses and high voltage grade power devices have to be used in the converter and is also bad to the design of post-regulator DC-DC converter.To solve this problem, this dissertation presented the active floating-charge-landing (FCL) and applied it in the conventional single phase Boost type PFC converter, analysed the circuit when FCL placed in differern positions of Boost converter. The single Boost PFC converter with FCL can reduce the output voltage as well as keeping the advantages of the PFC with Boost converter, for example, when the input voltage is 220V (AC), the output will be only 200V (DC). That extends the usage of the circuit, minishes the switch stress and is propitious to the design of the post-regulator DC-DC converter.This thesis mainly discussed following topics:1) introducting several widely used ways of power factor correction and comparing their characteristics, analyzing the principle of the conventional single phase Boost type PFC converter and several widely used control methods.2) presenting the single phase Boost type PFC converter with active floating-charge-landing, analyzing the principle and deducing circuit structures in different switching states, concluding the RMS value of the input current .3) analyzing the control strategy of the new converter, introducing the principle of one-cycle-control and applying it in the new converter, establishing the system structure. Simulating the system respectively in steady state, input voltage perturbation and load perturbation with simulation software.