skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: An Improved Distributed Secondary Control Method for DC Microgrids With Enhanced Dynamic Current Sharing Performance

Abstract

This paper proposes an improved distributed secondary control scheme for dc microgrids (MGs), aiming at overcoming the drawbacks of conventional droop control method. The proposed secondary control scheme can remove the dc voltage deviation and improve the current sharing accuracy by using voltage-shifting and slope-adjusting approaches simultaneously. Meanwhile, the average value of droop coefficients is calculated, and then it is controlled by an additional controller included in the distributed secondary control layer to ensure that each droop coefficient converges at a reasonable value. Hence, by adjusting the droop coefficient, each participating converter has equal output impedance, and the accurate proportional load current sharing can be achieved with different line resistances. Furthermore, the current sharing performance in steady and transient states can be enhanced by using the proposed method. The effectiveness of the proposed method is verified by detailed experimental tests based on a 3 × 1 kW prototype with three interface converters.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Electricity Delivery and Energy Reliability (OE); National Natural Science Foundation of China (NNSFC)
OSTI Identifier:
1337144
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: IEEE Transactions on Power Electronics; Journal Volume: 31; Journal Issue: 9
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; Current sharing; dc microgrid (MG); droop control; low-bandwidth communication (LBC); secondary control

Citation Formats

Wang, Panbao, Lu, Xiaonan, Yang, Xu, Wang, Wei, and Xu, Dianguo. An Improved Distributed Secondary Control Method for DC Microgrids With Enhanced Dynamic Current Sharing Performance. United States: N. p., 2016. Web. doi:10.1109/TPEL.2015.2499310.
Wang, Panbao, Lu, Xiaonan, Yang, Xu, Wang, Wei, & Xu, Dianguo. An Improved Distributed Secondary Control Method for DC Microgrids With Enhanced Dynamic Current Sharing Performance. United States. doi:10.1109/TPEL.2015.2499310.
Wang, Panbao, Lu, Xiaonan, Yang, Xu, Wang, Wei, and Xu, Dianguo. 2016. "An Improved Distributed Secondary Control Method for DC Microgrids With Enhanced Dynamic Current Sharing Performance". United States. doi:10.1109/TPEL.2015.2499310.
@article{osti_1337144,
title = {An Improved Distributed Secondary Control Method for DC Microgrids With Enhanced Dynamic Current Sharing Performance},
author = {Wang, Panbao and Lu, Xiaonan and Yang, Xu and Wang, Wei and Xu, Dianguo},
abstractNote = {This paper proposes an improved distributed secondary control scheme for dc microgrids (MGs), aiming at overcoming the drawbacks of conventional droop control method. The proposed secondary control scheme can remove the dc voltage deviation and improve the current sharing accuracy by using voltage-shifting and slope-adjusting approaches simultaneously. Meanwhile, the average value of droop coefficients is calculated, and then it is controlled by an additional controller included in the distributed secondary control layer to ensure that each droop coefficient converges at a reasonable value. Hence, by adjusting the droop coefficient, each participating converter has equal output impedance, and the accurate proportional load current sharing can be achieved with different line resistances. Furthermore, the current sharing performance in steady and transient states can be enhanced by using the proposed method. The effectiveness of the proposed method is verified by detailed experimental tests based on a 3 × 1 kW prototype with three interface converters.},
doi = {10.1109/TPEL.2015.2499310},
journal = {IEEE Transactions on Power Electronics},
number = 9,
volume = 31,
place = {United States},
year = 2016,
month = 9
}
  • This paper presents a new distributed control framework to coordinate inverter-interfaced distributed energy resources (DERs) in island microgrids. We show that under bounded load uncertainties, the proposed control method can steer the microgrid to a desired steady state with synchronized inverter frequency across the network and proportional sharing of both active and reactive powers among the inverters. We also show that such convergence can be achieved while respecting constraints on voltage magnitude and branch angle differences. The controller is robust under various contingency scenarios, including loss of communication links and failures of DERs. The proposed controller is applicable to lossymore » mesh microgrids with heterogeneous R/X distribution lines and reasonable parameter variations. Simulations based on various microgrid operation scenarios are also provided to show the effectiveness of the proposed control method.« less
  • Abstract not provided.
  • As a line-focus concentrating solar power (CSP) technology, linear Fresnel collectors have the potential to become a low-cost solution for electricity production and a variety of thermal energy applications. However, this technology often suffers from relatively low performance. A secondary reflector is a key component used to improve optical performance of a linear Fresnel collector. The shape of a secondary reflector is particularly critical in determining solar power captured by the absorber tube(s), and thus, the collector's optical performance. However, to the authors' knowledge, no well-established process existed to derive the optimal secondary shape prior to the development of amore » new adaptive method to optimize the secondary reflector shape. The new adaptive method does not assume any pre-defined analytical form; rather, it constitutes an optimum shape through an adaptive process by maximizing the energy collection onto the absorber tube. In this paper, the adaptive method is compared with popular secondary-reflector designs with respect to a collector's optical performance under various scenarios. For the first time, a comprehensive, in-depth comparison was conducted on all popular secondary designs for CSP applications. In conclusion, it is shown that the adaptive design exhibits the best optical performance.« less
  • Increasing demand for better detection performance with a simultaneous reduction in size, weight and power consumption has motivated the use of compact semiconductors as photo-converters for many gamma-ray and neutron scintillators. The spectral response of devices such as silicon avalanche photodiodes (APDs) is poorly matched to many common high-performance scintillators. We have developed a generalized analytical method that utilizes an optical reference database to match scintillator luminescence to the excitation spectrum of high quantum efficiency semiconductor detectors. This is accomplished by the fabrication and application of a series of high quantum yield, short fluorescence lifetime, wavelengthshifting coatings. Furthermore, we showmore » here a 22% increase in photoelectron collection and a 10% improvement in energy resolution when applying a layered coating to an APD-coupled, cerium-doped, yttrium oxyorthosilicate (YSO:Ce) scintillator. Wavelength-shifted radioluminescence emission and rise time analysis are also discussed.« less
  • The paper describes a dc-dc power module based on a single-stage current-fed converter structure. Control is made according to a time-sharing strategy allowing simultaneous regulation of output voltage and input current. This solution is suitable for high-performance space and avionic applications, giving high efficiency, compactness, and accuracy, speed and robustness of control. Theoretical analysis, design criteria, and experimental results are reported. Application to radar supplies is discussed.