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Virtual Synchronous Machine Phase Synchronization

Petti, Joseph / J (2018) Virtual Synchronous Machine Phase Synchronization. Master's Thesis, University of Pittsburgh. (Unpublished)

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This thesis enables virtual synchronous machine (VSM) control by contributing resynchronization of phase among parallel-connected distributed generation (DG). The work presents simulation, modeling, and testing to demonstrate the benefits and liabilities that VSMs control offers in place of the conventional phase-locked loop (PLL). This investigation came to light due to the recent and impending increased penetration of power electronic based generation. As the grid modernizes, generation has shifted and will continue to shift from conventional power plants that operate large synchronous generators to power electronics-interfaced DG. This shift is due to environmental, financial, and sustainable goals set by the government, corporations, and individual citizens. Particularly renewable energy, such as solar and wind, have become popular replacements because of the availability of the resources. Both of these generation types pass through the control of power electronics when injecting power onto the grid.
PLLs have been the main tool used to synchronize power electronic sources to the grid they are operating within. They have proven to be an excellent tool for synchronization but in some situations this is also their downfall. They synchronize to the strongest source available and mimic the behavior of this source regardless of quality. As the distributed power electronic generation profile grows and the synchronous machine generation profile declines the grid will lose valuable inertia. This inertia is readily available today because of the large amount of synchronous generation still present. Inertia is used to sustain stable operation in the wake of grid disturbances, such as faults.
The grid will become less stable, as increased penetration of DG dissipates inertia. Virtual synchronous machines have become a solution to solve this issue, simultaneously allowing for mass penetration of renewable energy. The virtual synchronous machine is a power electronic converter control method that utilizes the swing equation, inherent to synchronous machines, instead of the conventional PLL, in order to synchronous to the gird. Virtual synchronous machines mimic inertia, where synchronous machines inherently operate with inertia, and can aid grid stability in wake of grid disturbances.
As this power electronic based generation is added to the grid inertia can be lost. The VSM is a control strategy that gives power electronic based generation inertia, adding robustness to the grid. The VSM is very stout in the area of frequency stability but not in phase stability. This work aims to improve the VSM in order to give it better phase stability. This improvement will make VSMs a more useful tool in terms of stabilizing the grid.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Petti, Joseph / Jjj.petti@yahoo.comjjp700000-0003-1391-746X
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairReed, Gregorygfr3@pitt.edugfr3
Committee MemberGrainger, Brandonbmg10@pitt.edubmg10
Zhi-Homg, Maozmh4@pitt.eduzmh4
Date: 11 June 2018
Date Type: Publication
Defense Date: 21 March 2018
Approval Date: 11 June 2018
Submission Date: 23 March 2018
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 73
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Electrical and Computer Engineering
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: Virtual Synchronous Machine, Renewable Energy, Inertia, Grid Stability
Date Deposited: 11 Jun 2018 17:47
Last Modified: 11 Jun 2018 17:47

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