Recent developments of multiport DC/DC converter topologies, control strategies, and applications: A comparative review and analysis

Recent developments in renewable energy-based power systems and smart grids have brought challenges to designing new power conversion systems. On account of the intermittent nature of the renewable sources and unpredictability of the load demand, a combination of two or more energy sources and auxiliary storage systems is usually mandatory to meet the load demand, improve dynamic and steady-state characteristics, and reliability and availability of the system. Conventionally, SISO (single-input-single-output) DC/DC converters are arranged in parallel at a common DC bus to exchange power. In this scheme, separate conversion stages are employed for respective renewable energy sources (RES) and energy storage systems (ESS), and the converters would be controlled independently. However, the multistage configuration generally leads to a large size due to the large number of conversion stages, relatively high cost, and low efficiency and power density. Also, the independent control of several converters and communication among the sources make the system complex. In order to overcome these disadvantages, multi-port DC/DC converters (MPDC) have been proposed. MPDCs are preferred against several independent converters in terms of efficiency, component count, size, cost, and performance point of view. In addition to RES, MPDCs can be utilized in other applications such as electric/hybrid vehicles, telecommunication and satellites, and UPSs. This paper aims to consider the recent advances in MPDC from a topology and control point of view and provide a helpful framework and point of reference for future converter design and applications.