Unity-power-factor PWM rectifier with DC ripple compensation

This paper presents a new topology of PWM rectifier which can achieve unity-power-factor on the AC supply side and ripple-reduction on the DC output side. The main circuit of this rectifier is accomplished by adding only a pair of switches to a conventional PWM rectifier. And it does not need the large DC capacitor or passive L-C resonant circuit. These additional switches and PWM rectifier are controlled not only to make a unity power factor but also to reduce the ripple current. The effectiveness of this circuit is confirmed by the experiments and analysis. This rectifier is useful for UPS and DC power supply, especially in case that the batteries are connected to the DC line