Study On Power Factor Correction Based On One-cycle Control

With the development of power electronics and the increase of electrical equipment, thepower harmonic pollution is becoming worse. Eliminating harmonic pollution caused by powerelectronic devices, especially AC / DC rectifier, improving the quality of power network andimproving system power factor corrector have been focused on to research in our country andabroad. So studying a power factor correction method, which is simple, good dynamicperformance and easy-to-stability has become a hot issue of power electronicsBased on referring to lots of the literature, the paper summarizes power factor correctiontechnology situation at home and aboard and lists several active power factor correctiontechnologies which are popular currently. On this basis, the single-phase and three-phase powerfactor corrections (PFC) Technologies with one-cycle control are studied. The paper firstlyintroduces the One-Cycle Control method and discusses its basic principles, nature,characteristics and theoretical basis in illustration of Buck circuit. This control technology then isapplied to single-phase bridge and three-phase full-bridge rectifier. With theoretical analyses thepaper deduces the control law of one-cycle-controlled single-phase and three-phase voltage-typePWM rectifier. In order to make the input current track the input voltage better and improve thepower factor, the paper modifies the traditional one-cycle control method and let input voltagemultiply a gain K, then the result is added to the sensed current, the sum of them is changed ascontrol subject. The new equation is deduces by theoretical analysis. The paper gives the largesignaland voltage small-signal model of the single–phase rectifier controlled by modified onecycle.And in order to reduce switching loss, the method including one-cycle control and withoutmaximum-phase control is applied to rectifier. Finally the MATLAB simulations at single-phaseand three-phase system are carried respectively, and the experiment on single-phase system isdesigned.The simulations and experimental results show that improved control does not need ofmultiplier and input voltage detection device, the circuit is easy to realize, its power factor canreach above 0.99, THD is less than 5%, and for three-phase system,.the three-phase currents always maintain symmetrical and the phase bias is 120 o. It is also verified that the system canremain stability and has good dynamic performance when the load is changing.