Analysis and Design of DC-Bus Voltage Controller of Energy Storage Systems in DC Microgrids

Yoon-Cheul Jeung,Dong-Choon Lee,Duc Dung Le

doi:10.1109/access.2019.2939176

Abstract

In this paper, a novel voltage controller of energy storage system (ESS) in DC microgrids (DC-MG) is proposed to enhance the DC-bus voltage stability. At first, a mathematical model of the DC-MG is developed in a state-space form. Then, the voltage controller of the ESS is designed by using the methodology of the IDA-PBC (interconnection and damping assignment-passivity-based control) with an integral action. System stability has been analyzed with passivity-based stability criterion (PBSC). The proposed controller gives the robust performance to the parameters variation. The validity of the proposed control scheme has been verified by the hardware-in-the-loop simulation (HILS) results.

Highlights

Due to the increase of DC sources and DC loads, DC microgrids (DC-MGs) have become an increasingly popular solution for transmission and distribution [1]
In DC microgrid applications, the IDA-PBC theory has been applied to design the voltage controller of the boost, buck-boost and dualactive bridge converters to mitigate the effects of the constant power load (CPL), where the control performance is satisfactory at normal conditions [25]–[28]
The two VSCs are modelled as the DC/DC boost converters with ideal DC sources, which are connected to the DC bus through the line impedance to provide the DC power for the loads

Summary

INTRODUCTION

Due to the increase of DC sources and DC loads, DC microgrids (DC-MGs) have become an increasingly popular solution for transmission and distribution [1]. In DC microgrid applications, the IDA-PBC theory has been applied to design the voltage controller of the boost, buck-boost and dualactive bridge converters to mitigate the effects of the CPL, where the control performance is satisfactory at normal conditions [25]–[28]. The two VSCs are modelled as the DC/DC boost converters with ideal DC sources, which are connected to the DC bus through the line impedance to provide the DC power for the loads. B. DC SOURCES In order to investigate the nonlinear characteristics of the DC microgrid system and the voltage control performance below the switching frequency, the equivalent circuit model of the VSCs is usefully employed [17], [19], [31], [32]. If the VSC is modelled with a dependent voltage source as shown in Fig. 3(b), (1) only is needed

CONSTANT POWER LOADS

CONTROLLER DESIGN

CONCLUSION