Research Of Dc-Side Active Power Filter Based On Soft-Switching

To remove such defects as excessive switching loss, complicated detection andcontrol methods of traditional PWM active power filter (APF), this paper works at thestudy of a new soft-switching DC side APF. The emphasis of this thesis is laid on theanalysis of principle of main circuit, study of control method and computer simulationand experiment technology. First of all, after the necessary discussion on current study situation of APF, anew DC side APF is proposed based on one cycle control theory. Using bi-directionalboost converter as its main circuit, the single-phase APF is shunted at the DC side ofrectifier, compensating the harmonic and reactive current of nonlinear loads.Compared with the traditional shunt APFs, there is no need to sense load current, noneed to calculate the harmonic and reactive component of the load current, and noneed for multiplier. In contrast to the traditional power factor corrector(PFC), the newDC side APF deals with less power and features low rate, small volume, highefficiency and so on. Secondly, the soft-switching technology is employed here for reducing switchingloss further, and the main power switches in the new DC side APF have realized zerovoltage switching(ZVS). At the same time the switches can avoid excessive voltagestress by use of active clamp technology. Needing no additional control method, byactive clamp and ZVS the DC side APF not only reduces the switching loss greatlybut also obeys the original control rule, increasing operating efficiency as well. Thismethod has something of significance in the field of high volume APF. Next, a fast simulation method is proposed in this paper by combination ofrespective features of MATLAB and PSPICE. The powerful calculation faculty andadvantageous program of MATLAB is helpful to increase the speed of convergencewhen using PSPICE, and this method is of universality. The simulation results verifythe validity of proposed method and the superiority of this simulation method. Finally, the experimental control circuit is implemented by using UC3875 as itscore part. The achieved results are in good agreement with expected performance.