In most power electronic applications, the power input is in the form of a 50-Hz or 60-Hz sine-wave AC voltage provided by the electric utility, which is then converted to a DC voltage. Increasingly, the trend is to convert the input AC into DC in an uncontrolled manner, using rectifiers and diodes.

In most of the applications that use uncontrolled rectifiers, the rectifiers are supplied directly from the utility source without a 50/60 Hz transformer ” a costly and bulky device. In non-power, factor-corrected applications, a large capacitor is often connected as a filter on the DC side. This capacitor is charged to a value close to the peak of the AC input voltage, and the DC link voltage is converted for use throughout the system. This design guide describes basic techniques for converting the generated DC link voltage for use throughout a system.