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Dynamic Control of DC-DC Converters for DC Microgrid Applications.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Dynamic Control of DC-DC Converters for DC Microgrid Applications./
作者:	Babaiahgari, Bhanu Shankar.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2021,
面頁冊數:	108 p.
附註:	Source: Dissertations Abstracts International, Volume: 83-03, Section: B.
Contained By:	Dissertations Abstracts International83-03B.
標題:	Electrical engineering. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28650581
ISBN:	9798544236283

Dynamic Control of DC-DC Converters for DC Microgrid Applications.
Babaiahgari, Bhanu Shankar.

Dynamic Control of DC-DC Converters for DC Microgrid Applications. - Ann Arbor : ProQuest Dissertations & Theses, 2021 - 108 p.

Source: Dissertations Abstracts International, Volume: 83-03, Section: B.

Thesis (Ph.D.)--University of Colorado at Denver, 2021.

This item must not be sold to any third party vendors.

In spite of the excellent characteristics of DC microgrids, effective protection schemes for DC microgrids still remain a challenge. One of the requirements for DC microgrids is to have power flow within the system balanced at all times for the most reliable and efficient operation. This process can become complicated, especially in situations where the system is affected by major disturbances that can evolve from different sections within it. Though there are existing higher level techniques (i.e., optimization, model predictive learning, etc.) that can help obtaining the operating power set points for each unit in DC microgrids, the integration and coordination among the hardware and optimization layers that have distinct convergence rates is a difficult task. Moreover, all system participants, like micro-source, energy storage device, and load device, are connected in parallel to the DC bus through the converters, ensuring the stability of the DC bus voltage is a key issue for the stable operation of the DC microgrid.Therefore this work investigates the consequences on DC microgrid performance due to various disturbances and faults. Then, dynamic protection based control schemes are proposed for DC-DC converters to ensure DC microgrid systems stability and better performance at all times. This work is organized into the following three projects.The first project focuses on the coordinated control for a DC microgrid for better system performance in handling instantaneous disturbances. For this purpose, a dual-layer hierarchical control architecture is proposed. The primary control layer regulates the power flow between the generation units using a droop control with adaptive gain adjustments. The secondary layer is devoted to performing dynamic system optimization. In order to coordinate the primary level controls and its protection with secondary level optimization, in-layer and inter-layer functions are designed to ensure that the system is optimally balanced at all times even during disturbances.The performance of DC microgrids can be affected substantially by the presence of constant power loads (CPLs). The CPLs induce non-linearities in the system which can have destabilizing effect. For this reason, the stability for DC microgrids is analyzed in the second project. A novel method using Lyapunov stability theorem is introduced for computing the stability graphically, often termed as domain (or region) of attraction (DOA), in order to provide a proper guideline for determining the maximum power that can be supplied to the CPL without affecting the stable operation. Furthermore, the stability analysis is extended to interconnected DC microgrids.Theoretically, it can be proved that the stability of DC microgrid system is affected by reduced DOA when it is subjected to an instant increase in CPL power. The third project analyses the stability of DC microgrids with CPLs during these transient-states and is proven from simulation and experimental results that the system becomes unstable. Therefore, a dynamic stabilizer that controls the stability region using variable inductor is proposed in order to guarantee stable operation during transient states. The proposed stabilizer can stabilize the system for wide range of CPL transients without affecting the main control objectives. Furthermore, a control law is formulated for the stabilizer to minimize the power loss in the circuit during normal operating conditions.All design, modeling and control ideas presented in this work were extensively verified both in simulation and experiments.

ISBN: 9798544236283Subjects--Topical Terms:

649834
Electrical engineering.
Subjects--Index Terms:

Hardware integration

Dynamic Control of DC-DC Converters for DC Microgrid Applications.
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245 1 0 $a Dynamic Control of DC-DC Converters for DC Microgrid Applications.
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300 $a 108 p.
500 $a Source: Dissertations Abstracts International, Volume: 83-03, Section: B.
500 $a Advisor: Park, Jae-Do.
502 $a Thesis (Ph.D.)--University of Colorado at Denver, 2021.
506 $a This item must not be sold to any third party vendors.
520 $a In spite of the excellent characteristics of DC microgrids, effective protection schemes for DC microgrids still remain a challenge. One of the requirements for DC microgrids is to have power flow within the system balanced at all times for the most reliable and efficient operation. This process can become complicated, especially in situations where the system is affected by major disturbances that can evolve from different sections within it. Though there are existing higher level techniques (i.e., optimization, model predictive learning, etc.) that can help obtaining the operating power set points for each unit in DC microgrids, the integration and coordination among the hardware and optimization layers that have distinct convergence rates is a difficult task. Moreover, all system participants, like micro-source, energy storage device, and load device, are connected in parallel to the DC bus through the converters, ensuring the stability of the DC bus voltage is a key issue for the stable operation of the DC microgrid.Therefore this work investigates the consequences on DC microgrid performance due to various disturbances and faults. Then, dynamic protection based control schemes are proposed for DC-DC converters to ensure DC microgrid systems stability and better performance at all times. This work is organized into the following three projects.The first project focuses on the coordinated control for a DC microgrid for better system performance in handling instantaneous disturbances. For this purpose, a dual-layer hierarchical control architecture is proposed. The primary control layer regulates the power flow between the generation units using a droop control with adaptive gain adjustments. The secondary layer is devoted to performing dynamic system optimization. In order to coordinate the primary level controls and its protection with secondary level optimization, in-layer and inter-layer functions are designed to ensure that the system is optimally balanced at all times even during disturbances.The performance of DC microgrids can be affected substantially by the presence of constant power loads (CPLs). The CPLs induce non-linearities in the system which can have destabilizing effect. For this reason, the stability for DC microgrids is analyzed in the second project. A novel method using Lyapunov stability theorem is introduced for computing the stability graphically, often termed as domain (or region) of attraction (DOA), in order to provide a proper guideline for determining the maximum power that can be supplied to the CPL without affecting the stable operation. Furthermore, the stability analysis is extended to interconnected DC microgrids.Theoretically, it can be proved that the stability of DC microgrid system is affected by reduced DOA when it is subjected to an instant increase in CPL power. The third project analyses the stability of DC microgrids with CPLs during these transient-states and is proven from simulation and experimental results that the system becomes unstable. Therefore, a dynamic stabilizer that controls the stability region using variable inductor is proposed in order to guarantee stable operation during transient states. The proposed stabilizer can stabilize the system for wide range of CPL transients without affecting the main control objectives. Furthermore, a control law is formulated for the stabilizer to minimize the power loss in the circuit during normal operating conditions.All design, modeling and control ideas presented in this work were extensively verified both in simulation and experiments.
590 $a School code: 0765.
650 4 $a Electrical engineering. $3 649834
650 4 $a Load. $3 3562902
650 4 $a Simulation. $3 644748
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650 4 $a Methods. $3 3560391
650 4 $a Energy storage. $3 652130
650 4 $a Systems stability. $3 3680640
650 4 $a Optimization. $3 891104
650 4 $a Equilibrium. $3 668417
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650 4 $a Engineering. $3 586835
650 4 $a Energy. $3 876794
653 $a Hardware integration
653 $a Disturbances
653 $a Faults
653 $a Dynamic protection control schemes
653 $a Stability
653 $a Performance
653 $a Control
653 $a Constant power loads
690 $a 0544
690 $a 0791
690 $a 0537
710 2 $a University of Colorado at Denver. $b Electrical Engineering. $3 2049763
773 0 $t Dissertations Abstracts International $g 83-03B.
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