Design and Implementation of Multiport Energy Routers Toward Future Energy Internet

This article presents a hybrid ac/dc system constructed by multiport energy routers (MERs), which have potential application prospects in future energy Internet. Two typical types of MER in the system are studied, and the selected main circuits are easy to realize multiple forms of power supply with high reliability, plug-and-play access of distributed generations, and high expansibility of power ports. The corresponding control and protection systems are developed to ensure the regular operation of MERs, and a smart energy management scheme is presented for the power flow management of MERs to meet the expectations of power consumers. Two MER prototypes are implemented, of which the experimental results validate the correctness of parameter design and the effectiveness of the control and energy management strategies, showing the satisfactory performance of MERs.

I. Introduction

Nowadays with the increasing number of distributed generations (DGs) integrated into the power grid and the increasing demand for intelligence and informatization of the smart grid, it is much needed for the present distribution power system to adapt these changes. In order to help the traditional distribution grid to cope with these new challenges, the concept of energy Internet (EI) [1] was proposed, which is aimed to combine DGs and the existing power grid by highly integrating bidirectional flows of information and electricity. One of the key elements to achieve EI is energy router (ER) [2], also called power router [3]. The concept of ER is developed from electronic power transformer (EPT) [4], also known as solid-state transformer [5]. Based on the basic power conversion function of EPT, ER also has other attractive characteristics including DGs plug-and-play integration, intelligent energy management, information interaction, etc. The emergence of ER provides reliable solutions for power quality control [6], ac/dc hybrid operation [7], bidirectional power flow transmission [8], and formulation of user side energy management scheme [9]. It can be predicted that ER will play a key role in the coordinated operation control and intelligent energy management of smart grid [10].