A Novel Buck–Boost Converter Combining KY and Buck Converters

In this letter, a buck-boost converter, i.e., 2D converter with a positive output voltage, is presented, which combines the KY converter and the traditional synchronously rectified (SR) buck converter. By doing so, the problem in voltage bucking of the KY converter can be solved, thereby increasing the application capability of the KY converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output current, thereby not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Above all, both the KY converter and the SR buck converter, combined into a buck-boost converter with no right-half plane zero, use the same power switches, thereby causing the required circuit to be compact and the corresponding cost to be down. Furthermore, during the magnetization period, the input voltage of the KY converter comes from the input voltage source, whereas during the demagnetization period, the input voltage of the KY converter comes from the output voltage of the SR buck converter.