Communication-Theoretic Model of Power Talk for a Single-Bus DC Microgrid
Abstract
:1. Introduction
2. Brief Overview of Microgrids’ Control
2.1. Control Architecture
2.2. Communications for Microgrid Control
2.3. How Power Talk Can Help
3. Power Talk in DC Microgrids
3.1. Preliminaries and Assumptions
3.2. All-to-All Power Talk: Time Division Multiple Access
3.2.1. Input Symbols
3.2.2. Output Symbols
- The described communication protocol requires prior knowledge of all possible points in the detection space of VSC j. As the detailed configuration of the MG is not known a priori, these values have to be learned, e.g., in a predefined training phase, during which each VSC constructs the detection space. This is analogous to the case of channel estimation in a standard communication system where a linear relation between the input and the output can be postulated. Power talk does not use such a relation; instead, in the training phase, each unit learns each possible output in the detection space and identifies which input combination causes the respective inputs.
- The output power of a VSC can also vary as a result of the load change, which happens arbitrarily and randomly. In particular, the current values of the loads can be seen as determining the state of the system or the state of the communication channel. Whenever they change, the structure of the detection space also changes, leading to incorrect decisions at the receivers if the detection space prior to change is still used. A strategy to deal with random state variations is to periodically repeat the training phase or to provide a mechanism that tracks the state changes and re-initiates the training phase whenever a change is detected. Section 5 outlines possible strategies to deal with this challenge.
4. Constraining Power Talk
4.1. The Signaling Space
4.2. The Detection Space
5. Dealing with Random Load Changes
6. Performance Evaluation
7. On the General Power Talk Channel Model
8. Conclusions and Discussion
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Notations | |
Symbols | Meaning |
Electrical Parameters | |
Bus voltage level | |
Output current of unit k | |
Output power of unit k | |
Reference voltage of the droop control | |
Virtual resistance of the droop control | |
Resistive part of the load | |
Constant power part of the load | |
Power Talk-related Parameters | |
Symbol slot duration | |
The bit combination sent bu unit k | |
Power talk symbol representing | |
The Hamming weight of | |
Power talk symbol received by unit j | |
Signaling space | |
Constraint space | |
Relative power deviation of unit j when unit k transmits | |
η, μ | Transmission, reception rate |
Abbreviations | |
Smart grid | SG |
Direct current, alternate current | DC, AC |
Microgrid | MG |
Distributed energy resource | DER |
Distributed generator | DG |
Energy storage system | ESS |
Time division multiple access | TDMA |
Voltage source converter | VSC |
Current source converter | CSC |
Piecewise Linear Electrical Circuit Simulation | PLECS |
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Angjelichinoski, M.; Stefanović, Č.; Popovski, P.; Blaabjerg, F. Communication-Theoretic Model of Power Talk for a Single-Bus DC Microgrid. Information 2016, 7, 18. https://doi.org/10.3390/info7010018
Angjelichinoski M, Stefanović Č, Popovski P, Blaabjerg F. Communication-Theoretic Model of Power Talk for a Single-Bus DC Microgrid. Information. 2016; 7(1):18. https://doi.org/10.3390/info7010018
Chicago/Turabian StyleAngjelichinoski, Marko, Čedomir Stefanović, Petar Popovski, and Frede Blaabjerg. 2016. "Communication-Theoretic Model of Power Talk for a Single-Bus DC Microgrid" Information 7, no. 1: 18. https://doi.org/10.3390/info7010018
APA StyleAngjelichinoski, M., Stefanović, Č., Popovski, P., & Blaabjerg, F. (2016). Communication-Theoretic Model of Power Talk for a Single-Bus DC Microgrid. Information, 7(1), 18. https://doi.org/10.3390/info7010018