PROJECT TITLE :

Ripple Eliminator to Smooth DC-Bus Voltage and Reduce the Total Capacitance Required

ABSTRACT:

Bulky electrolytic capacitors, that are often needed in dc systems to filter out voltage ripples, significantly cut back power density and system reliability. During this paper, a ripple eliminator, that may be a bidirectional buck–boost converter terminated with an auxiliary capacitor, is adopted to interchange bulky capacitors in dc systems. The voltage ripples on the terminals (i.e., the dc bus) will be transferred to the auxiliary capacitor, and therefore the ripples on the auxiliary capacitor can vary during a wide selection. Moreover, the common voltage of the auxiliary capacitor will be controlled either lower or more than the dc-bus voltage, that offers a wide operational vary for the ripple eliminator and conjointly the possibility of additional reducing the auxiliary capacitance. Hence, the full capacitance required will be abundant smaller than the originally required. When proposing a control strategy to transfer the voltage ripples to the auxiliary capacitor, three control strategies are proposed to regulate the auxiliary-capacitor voltage to keep up correct operation. Intensive experimental results are presented to demonstrate the performance.