Full-Bridge Diode-Clamped Four-Level Symmetric Switching Converter

Abstract

In this paper, we propose a novel full-bridge (FB) diode-clamped four-level symmetric switching converter. Multi-neighboring reference vector discontinuous PWM (MNRV DPWM) for FB topology was implemented through symmetric half-bridge (HB)-based control using an offset voltage addition method. A diode-clamped four-level symmetrical switching circuit with pulse-amplitude modulation (PAM) was proposed and its working principle was explained in detail. Voltage gain, duty loss factor, and zero-voltage-switching (ZVS) condition were derived by analyzing the steady-state operating characteristics of the proposed converter. The required input and output capacitance values were also calculated explicitly. The voltages across the series-connected input DC-link capacitors were well balanced and the output voltage was controlled in a simple linear manner by PAM. The proposed method has the advantage of reducing circulating current compared to the existing phase-shift method because there is an additional powering period. The effectiveness of the proposed converter was verified through simulation and prototype experiments. The power conversion efficiency exceeded 91.44% at an output power (PO) of 250W or higher, with a peak efficiency of 95.23% achieved at PO=750W.

Performance Analysis of Modulation Strategies in Single-Phase HBNPC Inverter Across Variable Operating Conditions

“…Neutral point-clamped multilevel inverters offer advantages like reduced filtering needs due to decreased harmonic components at higher voltage levels, improved efficiency through controlled reactive power flow, and simplified control methods utilizing a back-to-back inverter system. Nonetheless, they also present challenges such as increased complexity with higher level counts, leading to reduced reliability, and difficulties in controlling active power flow [21,22].…”