scholarly journals AC vs DC Distribution Efficiency: Are we on the Right Path?

Author(s):  
HASAN ERTEZA GELANI ◽  
FAIZAN DASTGEER ◽  
Mashood Nasir ◽  
sidra khan ◽  
Josep M. Guerrero

The concept of DC power distribution has gained interest within the research community in the past years; especially due to rapid prevalence of solar PVs as a tool for distributed generation in DC microgrids. Various efficiency analyses have been presented for the DC distribution paradigm, in comparison to the AC counterpart, considering a variety of scenarios. However, even after a number of such comparative efficiency studies, there seems to be a disparity in the results of research efforts - wherein a definite verdict is still unavailable: 'Is DC distribution a more efficient choice as compared to the conventional AC system?' A final verdict is absent primarily due to conflicting results. In this regard, system modeling and the assumptions made in different studies play a significant role in affecting the results of the study. The current paper is an attempt to critically observe the modeling and assumptions used in the efficiency studies related to the DC distribution system. Several research efforts will be analyzed for their approach towards the system upon which they have performed efficiency studies. Subsequently, the paper aims to propose a model that may alleviate the shortcomings in earlier research efforts and be able to give a definite verdict regarding the comparative efficiency of DC and AC networks for residential power distribution.

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4039
Author(s):  
Hasan Erteza Gelani ◽  
Faizan Dastgeer ◽  
Mashood Nasir ◽  
Sidra Khan ◽  
Josep M. Guerrero

The concept of DC power distribution has gained interest within the research community in the past years, especially due to the rapid prevalence of solar PVs as a tool for distributed generation in DC microgrids. Various efficiency analyses have been presented for the DC distribution paradigm, in comparison to the AC counterpart, considering a variety of scenarios. However, even after a number of such comparative efficiency studies, there seems to be a disparity in the results of research efforts, wherein a definite verdict is still unavailable. Is DC distribution a more efficient choice as compared to the conventional AC system? A final verdict is absent primarily due to conflicting results. In this regard, system modeling and the assumptions made in different studies play a significant role in affecting the results of the study. The current paper is an attempt to critically observe the modeling and assumptions used in the efficiency studies related to the DC distribution system. Several research efforts are analyzed for their approach toward the system upon which they have performed efficiency studies. Subsequently, the paper proposes a model that may alleviate the shortcomings in earlier research efforts and be able to give a definite verdict regarding the comparative efficiency of DC and AC networks for residential power distribution.


2019 ◽  
Vol 9 (3) ◽  
pp. 582 ◽  
Author(s):  
Hasan Gelani ◽  
Faizan Dastgeer ◽  
Kiran Siraj ◽  
Mashood Nasir ◽  
Kamran Niazi ◽  
...  

The paper investigates the system efficiency for power distribution in residential localities considering daily load variations. Relevant system modeling is presented. A mathematical model is devised, which is based on the data from the Energy Information Administration (EIA), USA, for analysis. The results reveal that the DC distribution system can present an equivalent or even better efficiency compared to the AC distribution network with an efficiency advantage of 2.3%, averaged over a day. Furthermore, the distribution systems are compared under various capacities of solar PV accounting for the effect of variation in solar irradiation over time.


2021 ◽  
Vol 9 ◽  
Author(s):  
Wei Teng ◽  
Yuejiao Wang ◽  
Shumin Sun ◽  
Yan Cheng ◽  
Peng Yu ◽  
...  

DC power distribution systems will play an important role in the future urban power distribution system, while the charging and discharging requirements of electric vehicles have a great impact on the voltage stability of the DC power distribution systems. A robust control method based on H∞ loop shaping method is proposed to suppress the effect of uncertain integration on voltage stability of DC distribution system. The results of frequency domain analysis and time domain simulation show that the proposed robust controller can effectively suppress the DC bus voltage oscillation caused by the uncertain integration of electric vehicle, and the robustness is strong.


Author(s):  
Faizan Dastgeer ◽  
Hafiz Muhammad Anees ◽  
Hasan Erteza Gelani ◽  
Kashif Amjad ◽  
Muhammad Rameez Javeed

DC power distribution has become a topic of interest in the recent past, despite being given up a long time. A number of research efforts have been carried out in this field; especially the idea of DC distribution for microgrids has witnessed a significant amount of time and attention. System efficiency is one of the under-research areas of this field that has witnessed a lot of research efforts which were generally simulation based studies. Detailed mathematical efficiency analysis is missing in the present body of knowledge. In this regard, the current research effort aims to present a foundation level mathematical efficiency analysis set-up that may be used as an analytical testbed for different efficiency studies especially those related to the comparative evaluation of DC and AC systems. The current effort highlights the strong dependence of AC and DC distribution system efficiency on the factor of time. The efficiency advantage of DC over AC or vice versa within a specified duration depends on the ratio of DC and AC grid powers summed over the duration.


Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 4002
Author(s):  
Yao ◽  
Jianfu ◽  
Lu ◽  
Zhanqing ◽  
Zipan ◽  
...  

The connection mode of the direct current (DC) power distribution system and the alternating current (AC) system is the foundation of system design, and it is also one of key technologies of the DC power distribution network. Based on the topology structure, grounding method, main equipment parameters, load parameters and system control protection strategy of the DC power distribution system, this paper establishes the system simulation model in the case of configuring the connection transformer and not configuring the connection transformer. Simulation results show that, when no connecting transformer is installed, the interaction between AC and DC systems will be great when faults occur, and the cost of converter valves and DC reactors will be increased. When connecting transformers are installed, the interaction between AC and DC systems can be effectively isolated, and the operation reliability of the system will be greatly improved while the cost is saved. Therefore, it is recommended to configure an independent connection transformer in the DC distribution system.


Author(s):  
Oladimeji Joseph Ayamolowo ◽  
Chukwunonso Anthony Mmonyi ◽  
Samson Olasunkanmi Adigun ◽  
Olabisi Abdullahi Onifade ◽  
Kehinde Adetunji Adeniji ◽  
...  

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 775
Author(s):  
Sheng-Yu Tseng ◽  
Jun-Hao Fan

Due to the advantages of power supply systems using the DC distribution method, such as a conversion efficiency increase of about 5–10%, a cost reduction of about 15–20%, etc., AC power distribution systems will be replaced by DC power distribution systems in the future. This paper adopts different converters to generate DC distribution system: DC/DC converter with PV arrays, power factor correction with utility line and full-bridge converter with multiple input sources. With this approach, the proposed full-bridge converter with soft-switching features for generating a desired voltage level in order to transfer energy to the proposed DC distribution system. In addition, the proposed soft-switching full-bridge converter is used to generate the DC voltage and is applied to balance power between the PV arrays and the utility line. Due to soft-switching features, the proposed full-bridge converter can be operated with zero-voltage switching (ZVS) at the turn-on transition to increase conversion efficiency. Finally, a prototype of the proposed full-bridge converter under an input voltage of DC 48 V, an output voltage of 24 V, a maximum output current of 21 A and a maximum output power of 500 W was implemented to prove its feasibility. From experimental results, it can be found that its maximum conversion efficiency is 92% under 50% of full-load conditions. It was shown to be suitable for DC distribution applications.


Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5863
Author(s):  
Arthur Santos ◽  
Gerald Duggan ◽  
Stephen Frank ◽  
Daniel Gerber ◽  
Daniel Zimmerle

Advances in power electronics and their use in Miscellaneous Electric Loads (MELs) in buildings have resulted in increased interest in using low-voltage direct current (DC) power distribution as a replacement for the standard alternating current (AC) power distribution in buildings. Both systems require an endpoint converter to convert the distribution system voltage to the MELs voltage requirements. This study focused on the efficiency of these endpoint converters by testing pairs of AC/DC and DC/DC power converters powering the same load profile. In contrast to prior studies, which estimated losses based on data sheet efficiency and rated loads, in this study, we used part load data derived from real-world time-series load measurements of MELs and experimentally characterized efficiency curves for all converters. The measurements performed for this study showed no systematic efficiency advantage for commercially available DC/DC endpoint converters relative to comparable, commercially available AC/DC endpoint converters. For the eight appliances analyzed with the pair of converters tested, in 50%, the weighted energy efficiency of the DC/DC converter was higher, while, for the other 50%, the AC/DC converter was. Additionally, the measurements indicated that the common assumption of using either data sheet efficiency values or efficiency at full load may result in substantial mis-estimates of the system efficiency.


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