Autonomous power sharing for AC/DC HMGS using decentralized modified droop method for interlinking converter

Abstract

<p>The present trend of integrating renewable energy sources (RES) in AC/DC hybrid micro grid systems (HMGS) has certainly reduced the greenhouse gases and provides the variety of power sources for micro grid (MG). Interlinking converter (ILC) is the main converter for interconnecting AC/DC sub-grids with a variety of features like autonomous bidirectional power sharing, reducing the power conversions in the grid and additionally a featuring aspect for energy management system (EMS). Interlinking converters are desired to maintain stable frequency, constant voltages at buses, reduce the power losses, reduce switching losses and control on circulating currents, most of the control methods could not achieve all. In this paper, the decentralized modified droop control method is presented which is significant in meeting the autonomous bidirectional AC/DC power load demand and in achieving the desired features. A three coordinated model is proposed where AC frequency, ILC power and DC voltage are the corresponding axis. The power sharing through the ILC is dependent on the AC frequency droop and DC voltage droop which occurs due to overloading. This control scheme is compatible for interconnection with multi-port grids. This control schemes provide more reliable, stable and accurate results compare to conventional droop methods.</p>

Energy management system for AC/DC HMGS integrated with interconnected renewable sources and interlinking converter

“…During the time interval of 1-3 sec ILC-1 behaves as inverter with power as negative and for 3-6 sec ILC-1 behaves as rectifier with power as positive. The Figure 10 shows the performance of ILC-1 as inverter and rectifier, also there are no major differences in results as compared to only ILC connected to three phase system [27]. Figure 11 show the frequency variations due to load changes.…”

“…This power is termed as negative and converter performance is an inverter. The mathematical model of control scheme is shown in (27).…”