Dynamic Modeling of Shipboard AC/DC Interconnected Microgrids and Attenuation of Transient States Caused by Pulsating Load Changes

Mostafa Zamani ¹ ( Faculty of Electrical & Computer Engineering, Malek Ashtar University of Technology, Iran )
Arash Dehestani Kolagar ² ( Faculty of Electrical & Computer Engineering, Malek Ashtar University of Technology, Iran )
Mahdi Mossayebi ³ ( Faculty of Electrical & Computer Engineering, Malek Ashtar University of Technology, Iran )
Mohammad Reza Alizadeh Pahlavani ⁴ ( Faculty of Electrical & Computer Engineering, Malek Ashtar University of Technology, Iran )

Submited date : 2024-12-29 Accepted date : 2025-04-13

Keywords: Disturbance resulting from load switching, microgrid stability, pulsed load switching, microgrid dynamic modeling.,

Abstract :

AC/DC microgrids of modern vessels have undergone significant changes due to the increase of high-power loads and the development of energy storage systems. In this paper, the extracted microgrid model is the main model developed in the dq reference frame, and the simulation results show the dynamic effect caused by any instability between the AC and DC subsystems of the microgrid. Thus, according to the results of the simulations, the microgrid AC/DC subsystems will have different transient characteristics in case of disturbances such as short circuit, switching of high-power loads, and occurrence of electric arc, which lead to the instability of the microgrid. The ability of the microgrid to maintain stability largely depends on the damping of electromechanical oscillations by the controllers in the AC/DC microgrid, which makes the study and design of these controllers very important. In order to attenuate the transient states of the DC subsystem, the PI closed-loop controller is used in the energy storage system to control the duty cycle of the IGBT switches in the DC/DC converter. The results show that with the appropriate design of the controller of the energy storage system, the transient states in the DC subsystem, in case of instabilities caused by the load pulse changes, are significantly reduced and attenuate the transient states of the microgrid. In this article, the second Lyapunov method is used to evaluate the stability of AC/DC microgrid.

References:

[1] L. Xu et al., "A review of DC shipboard microgrids - part I: power architectures, Energy Storage, and Power Converters," IEEE Trans. on Power Electronics, vol. 37, no. 5, pp. 5155-5172, May 2022.
[2] N. Doerry, "Next generation integrated power systems (NGIPS) for the future fleet," in Proc. IEEE Electric Ship Technologies Symp., Baltimore, MD, USA, 14-16 Sept. 2009.
[3] P. S. Sarker, Dynamic Modeling, Stability Analysis and Control of AC/DC Interconnected Microgrid Using DQ-Transformation, Ph.D. Thesis, Temple Iniversity, USA, 2018.
[4] –, IEEE Recommended Practice for 1 kV to 35 kV Medium-Voltage DC Power Systems on Ships, IEEE Std. 1709-2010, pp. 1-54, Nov. 2010.
[5] –, IEEE Guide for the Design and Application of Power Electronics in Electrical Power Systems on Ships, IEEE Std. 1662-2008, pp. 1-72, 2009.
[6] –, IEEE Standard for Power Electronics Open System Interfaces in Zonal Electrical Distribution Systems Rated Above 100 kW, IEEE Std. 1826-2012, pp. 1-46, 2012.
[7] N. Doerry and J. Amy, “DC voltage interface standards for naval applications,” in Proc. IEEE Electric Ship Technologies Symp., 2015, pp. 318-325, Old Town Alexandria, VA, USA, 21-24 Jun. 2015.
[8] –, IEC/IEEE International Standard - Utility Connections in Port – Part 1: High Voltage Shore Connection (HVSC) Systems – General Requirements, IEC/IEEE 80005-1:2019, pp. 1-178, 2019.
[9] H. Zhang, Q. Wang, H. Chen, Y. Xu, and Y. Wang, "Comparative analysis of IEC 61000-4-30 evolution in power quality," in Proc. 21st Int. Conf. on Harmonics and Quality of Power, pp. 701-705, Chengdu, China, 15-18 Oct., 2024.
[10] M. Valdes and H. Floyd, "Considerations for adapting IEEE 1584-2002 arc flash study pesults to a post IEEE 1584-2018 risk assessment," IEEE Trans. Ind. Appl., vol. 57, no. 6, pp. 5562-5570, Aug. 2021.
[11] D. R. Doan, "Arc flash Calculations for Exposures to DC systems," IEEE Trans. Ind. Appl., vol. 46, no. 6, pp. 2299-2302, Dec. 2010.
[12] L. Xu, et al., "A review of DC shipboard microgrids - part II: control architectures, stability analysis, and protection schemes," IEEE Trans. on Power Electronics, vol. 37, no. 4, pp. 4195-4120, Oct. 2022.
[13] S. Kim, Protection Coordination in Marine DC Power Distribution Networks, Ph.D. Thesis, EPFL, Switzerland, 2020.
[14] H. Liu, H. Guo, J. Liang, and L. Qi, "Impedance-based stability analysis of MVDC systems using generator-thyristor units and DTC motor drives," IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 5, no. 1, pp. 5-13, Mar. 2016.
[15] –, IEEE Electric Ship Technologies Symposium, Baltimore, MD, USA, 14-16 Sept. 2009.
[16] N. Eghtedarpour and E. Farjah, "Power control and management in a Hybrid AC/DC microgrid," IEEE Trans. Smart Grid, vol. 5, no. 3, pp. 1494-1505, May 2014.
[17] K Chaijarurnudomrung, K. N. Areerak, and K. L. Areerak, "Modeling and stability analysis of AC-DC power system with controlled rectifier and constant power loads," WSEAS Trans. on Power Systems, vol. 6, no. 2, pp. 31-41, Apr. 2011.
[18] J. Shi, R. Amgai, and S. Abdelwahed, "Modelling of shipboard medium-voltage direct current system for system level dynamic analysis," IET Electrical Systems in Transportation, vol. 5, no. 4, pp. 156-165, Dec. 2015.
[19] Il-yop Chung, Wenxin Liu, David A Cartes, Soo-hwan Cho, and Hyun-koo Kang, "Controller optimization for bidirectional power flow in medium-voltage DC power systems," Journal of Electrical Engineener & Technology, vol. 6, no. 6, pp. 750-759, 2011.
[20] –, IEEE Energy Conversion Congress and Exposition, Alexandria, VA, USA, 10-13 Apr. 2012.
[21] P. S. Sarker and S. Biswas, "Modeling and non-linear stability analysis of ac/dc interconnected microgrid using dq-transformation considering generator dynamicsm," in Proc. 44th Annual Conference of the IEEE Industrial Electronics Society, pp. 4039-4044, Washington, DC, USA, 21-23 Oct. 2018.
[22] P. M. Andersonand C. A. A. Fouad, Power System Control and Stability, Second Edition, John Wiley & Sons, 2008.
[23] K. N. Areerak, S. V. Bozhko, G. M. Asher, and D. W. Thomas, “Stability analysis and modelling of AC-DC system with mixed load using DQ-transformation method," in Proc. IEEE Int. Symp. on Industrial Electronics, 6. pp., Cambridge, UK, 30 Jun.- 2 Jul. 2008.
[24] M, Djibo, Protection and Disturbance Mitigation of Next Generation Shipboard Power Systems. Ph.D. Thesis, Old Dominion University, USA, 2021.
[25] Y. Lu, Optimal Scheduling and Loadsharing of a Hybrid Power Plant with Gensets and Battery Banks, Master Thesis, Norwegian University of Science and Technology, Norway, 2019.
[26] J. Zhang, Bidirectional DC-DC Power Converter Design Optimization, Modeling and Control, Ph.D. Thesis, Virginia Polytechnic Institute, USA, 2008.
[27] N. Zohrabi, Distributed Predictive Control for MVDC Shipboard Power System Management, Ph.D. Thesis, Mississippi State University, USA, 2018.