Master–Slave Based Hierarchical Control for a Small Power DC-Distributed Microgrid System with a Storage Device

Seung-Woon Lee,Bo-Hyung Cho

doi:10.3390/en9110880

Abstract

In this paper, we analyze one of the main drawbacks of droop control-based DC microgrid systems, and propose a novel control method to overcome this problem. Typically, DC microgrid systems use droop control techniques to enable communication independency and expandability. However, as these advantages are based on bus quality and regulation abandonment, droop-based schemes have limitations in terms of high bus impedance and bus regulation. This paper proposes a novel master–slave based hierarchical control technique for a DC distribution system, in which a DC bus signaling method is used to overcome the communication dependency and the expandability limitations of conventional master–slave control methods. The concept and design considerations of the proposed control method are presented, and a 1 kW simulation under a Powersim (PSIM) environment and hardware prototype—built to verify the system—is described.

Highlights

Technological development and environmental protection concerns have led to the introduction of distributed energy resources (DERs)—such as gas- and wind-turbines and photovoltaic (PV) energy source—into microgrids [1,2,3,4,5]
This paper proposes a novel master–slave control method that eliminates the need for a replace additional communication, and controls the input power of device-stored energy instead of communication link
A DC distribution system controlled by a communication‐free master–slave‐based hierarchical control method is presented this paper.byAlthough droop control has many drawbacks, including

Summary

Introduction

Technological development and environmental protection concerns have led to the introduction of distributed energy resources (DERs)—such as gas- and wind-turbines and photovoltaic (PV) energy source—into microgrids [1,2,3,4,5]. The growth of PV into the most popular renewable energy source, as a result of its installation convenience, has helped to further the concept of the DC distribution system [6,7,8,9,10] Do such systems bring the advantages of PV-to-DC grid energy conversion efficiency, but they allow for the utilization of storage devices and digital loads [11]. Droop controls have many advantages, including communication independency and expandability, they can be widely used in microgrid environments requiring stable and reliable control These benefits come at the cost of decreased bus quality owing to voltage regulation and transient response on the bus and, incur high bus impedance [14,15,16,17,26]. These problems may result in difficulties of overall system optimization in terms of efficiency and stability

Methods

Results

Conclusion