UNITY POWER-FACTOR ZVS AC-TO-DC CONVERTERS WITH AN ACTIVE-FILTER

Unity power factor zero-voltage-switched ac-to-dc converters with an a ctive filter are proposed, The line voltage is supplied to ac-to-dc co nverters through the rectifier circuit with an input filter, to reduce high-frequency ripple components, The line current is almost synchron ized to the line voltage, due to the low impedance of the input filter . The forward zero-voltage-switched multiresonant converters (ZVS-MRC' s) are utilized for high-frequency operation and lossless switching, A n active filter is introduced to minimize the twice line-frequency rip ple component of the output voltage without large-size passive filters , Experimental results show that the proposed scheme gives good steady -state performances of the ac-to-dc converters.