Minimizing conduction losses in multiple active bridge converters across wide voltage ranges using advanced dual‐duty modulation

Multiple port DC/DC converters have applications in many fields: hybrid energy storage systems where batteries are combined with supercapacitors, multi‐level and multi‐modular inverters that need multiple DC sources, and DC microgrids. Among these converters, the Multiple Active Bridge (MAB) is particularly attractive due to its high power ratings and galvanic isolation capabilities. This paper introduces an advanced dual‐duty modulation technique for MAB converters designed to significantly reduce conduction losses over a wide range of input voltages by minimizing the harmonics’ reactive power on the AC stage. Consequently, it can improve the converter's efficiency when dealing with non‐constant voltage sources such as batteries and supercapacitors. The overall control technique is based on the dq‐frame control method under the first harmonic approach (FHA). This method is verified through simulations and implemented in a 1000 W triple‐port prototype. In the simulation, conductive and switching losses are modelled, and the trade‐off between these loss types is discussed. The experimental results affirm an overall improvement in efficiency for certain scenarios involving non‐unit voltage conversion ratios. The main contribution of the paper is the analysis of the modulation technique in a multiple active bridge converter. This converter has a limited input voltage range due to the increase of losses at a normalized gain different from one. From the analysis, a new modulation technique is presented which minimizes the conduction losses of the converter allowing it to work in a wider voltage range.