High-Performance Single Switch High Step-Up Quadratic DC-DC Converter With Switched Capacitor Cell

This article presents a single-switch high step-up quadratic DC-DC converter for DC microgrid applications. The quadratic boost converter is integrated with switched capacitor cell along with coupled inductor to achieve high gain at reduced duty ratio. The switched-capacitor cell is composed of two diodes and two capacitors. The capacitors charge in parallel and discharge in series to increase the converter’s gain. The coupled inductor turn ratio can be increased to elevate the converter’s gain further. The inductor at the input minimizes the current ripples and makes the input current to be continuous. Moreover, the proposed converter works as a passive clamp circuit to minimize large voltage spikes across the switch (MOSFET) and it has low $R_{ds}$ (on-state) to minimize the conduction losses. As a result, the device’s rating improves, losses decrease, and it becomes less expensive to switching devices of the converter. The energy leakage of the coupled inductor is recycled to the output capacitor, it can reduce the reverse recovery issue in diodes and increases efficiency of converter further. The proposed converter working principle and its analysis are explained with different operating modes. The performance of the converter is validated with laboratory hardware setup with rating of 160W. Here, the input and output voltages are considered at 20V and 400V, respectively. Finally, the superiority of the proposed converter is compared with existing literature in terms of gain, stress across various components, switching performance and efficiency.