Multi-Objective Design of Single-Phase Differential Buck Inverters With Active Power Decoupling

Abstract

The design of single-phase differential buck inverters has two important considerations, including reducing second-order ripple power using decoupling capacitors and increasing inverter performances. Using larger decoupling capacitors will improve the performance of ripple power reduction and efficiency while reducing power density. Such trade-off has not been fully modeled and investigated, leading to the sub-optimal design of inverters. To address that, in this paper, the trade-off among decoupling capacitance, inverter efficiency and power density are investigated through detailed mathematical modeling and sensitivity study. The trade-off of the volume and power loss of essential inverter components, including power switches, inductors and heatsinks, are also studied to facilitate the inverter design. A fast multi-objective design optimization method based on geometric programming is presented to optimize the inverter efficiency and power density. A 1 kW prototype of a Gallium Nitride (GaN) based inverter has been designed based on the proposed method. A hardware prototype of the inverter has been built and tested, which has an efficiency of 98.02% and power density $ {4.54\;\mathrm{{kW/dm^{3}}}}$ and matches 99% to the presented multi-objective design method. This validates the accuracy and effectiveness of the presented design approach considering detailed trade-off analysis.

Keywords

• Multi-objective design
• single-phase differential inverter
• power decoupling
• efficiency
• power density
• geometric program