Improved KY Converter

Abstract

In a KY boost converter, a short, high-current charging pulse occurs in each clock cycle, placing extreme stress on the components, especially the diode (D), the first capacitor (C1), and the second electronic switch (S2). By inserting a small inductor (L2), which can also be an air-core inductor, the charging current becomes sinusoidal. This reduces the maximum current and improves electromagnetic compatibility. The second inductor (L2) can be connected between the positive input terminal (1) and the positive terminal of the first electronic switch (S1), or between the junction of the negative terminal of the first electronic switch (S1) and the negative terminal of the first capacitor (C1) and the positive terminal of the second electronic switch (S2). The converter has a limited but linear voltage transformation ratio and, from a control engineering perspective, is a phase minimum system.The output voltage is very smooth due to the arrangement of the first coil (L1) and the output capacitor (C2).