$n$-Stage Bidirectional Quadratic Boost Converter with Reduced Switch Voltage and Current Stress

In this paper, a bidirectional n-stage quadratic boost converter (BQBC) with reduced switch voltage and current stress is proposed. The converter structure is formed using $n+1$ inductors, $n+1$ capacitors, and $2n+2$ MOSFETs, just like the conventional n-stage BQBC. The current and voltage stress reductions are achieved in the proposed n-stage BQBC by using a cascaded leg arrangement of the MOSFETs that are formed using $n+1$ MOSFETs out of the total MOSFETs. This stress reduction leads to reducing the rating of $n+1$ MOSFETs and improving the efficiency of the BQBC. The steady-state analysis of the BQBC with $n=1$ is presented in this paper. The components are designed for 200 W, 350 V, and 20 kHz with a source voltage of 48 V. The effect of parasitic elements on the output voltage and the efficiency is investigated. The experimental results of the BQBC are observed using the laboratory prototype and are presented. The performance comparison is carried out with the recently reported converter and BQBC. In addition to reducing stress and increasing efficiency, the main benefits of the proposed BQBC are a continuous source current and a common ground between the input and output ports.