# Modern MultiPort Converter Technologies: A Systematic Review
## 2 General Classification and Operation Principles
### Modular and Non-Modular Multiport Converters  
The quick rise in demand for the integration of renewable energy with numerous applications is what brought attention to modular multiport converters. These multiport converters make it very simple to add or remove a new energy source with fewer components than in the case of the application of conventional converters. As shown in [52], a modular multiport converter with a bidirectional port for battery charging applications (Figure 6) consists of six ports, from which three ports are input and the other three ports are output. Using Matlab/Simulink environment, the proposed topology is simulated, and the output results are plotted. The authors also provide a report that shows output data and a hardware prototype of the system.  
A similar approach is used in [53]. The proposed multiport converter with a modular structure is able to handle a number of sources and loads. A modular converter topology has been designed for usage in energy systems with multiple sources and multiple loads. The converter is based on a specific switching scheme, and this switching scheme has been used to examine the converter's working principle. In continuous conduction mode (CCM) and discontinuous conduction mode (DCM), the converter's steady-state operation has been described. It has been possible to identify and characterize many DCM modes. Studies on sensitivity analysis, loss and efficiency modeling, and dynamic characterization are also carried out.  
For non-modular multiport topology, the extension can be performed with the help of incorporating the fundamental structures in series. Two novel bridge-type dual input DC-DC converter topologies for combining two input energy sources are presented in [54]. The second topology is an upgraded version of the first of the two topologies. The load can receive power from the input energy sources concurrently from both converters. A thorough analysis of how the equivalent series resistance (ESR) of the passive elements (capacitor and inducer) affects the converter's voltage gain has been undertaken. The voltage gain of the converter is greatly decreased by the inductor and capacitor's ESR, according to the results of the ESR analysis.  
Figure 6: Structure of modular multiport system proposed.  
In [55] the authors provided analysis, design description, and experimental testing of modular and non-modular bidirectional converters for energy management in the household energy hub. Various applications of these converters are covered in this article. Eight modules using the new, extremely fast gallium nitride (GaN) transistor technology, which permits raising the switching frequency up to the region of megahertz, were used to implement the modular structure. New silicon carbide (SiC) transistors, which also enable the utilization of high switching frequencies and lower total volume and costs, were also applied for the non-modular topology. For the purpose of verifying various operational modes, the primary electronic components for planned prototypes, along with specifications of input/output parameters, have been defined.  
In [56] the authors offer a novel multiport DC/DC converter with a modular structure interconnected in a scalable matrix topology, offering a simultaneous low voltage/current rating and ultra-high voltage step-up ratio. This modular topology is proposed to help to transfer the power from the offshore wind turbine's generator to the terminals of high-voltage direct current transmission line (HVDC) connecting the wind turbine farms with the inland grid. Soft-switching is achieved for all power switches and the currents of series-connected converters which are auto-balanced thanks to the use of active clamping current-fed push-pull (CFPP) converters as sub-modules, which significantly reduce switching losses and control complexity.