Secondary voltage and frequency control for dispatchable virtual oscillator controlled inverters

With the introduction of more distributed energy resources (DERs) on the grid, there is also a decrease in the amount of rotating inertia that can be relied upon to keep the grid frequency and voltage stable. Grid following inverters (GFLs) connect renewable resources to the grid but do not have capabilities to control their output frequency and voltage, and are instead susceptible to any grid disturbances. Grid forming inverters (GFM) in contrast, are inverters that can help keep voltage and frequency stable; even in systems with high percentages of renewables or microgrids that are fully renewable based. In this thesis we examine three types of GFMs, droop controlled, virtual synchronous machine (VSM) controlled, and dispatchable virtual oscillator controlled (dVOC), in both their steady state and dynamic responses. The steady state responses are examined in order to determine how nonlinearities in the dVOC-based inverters compare to the linear behavior of droop and VSM control. Then, for the dynamic simulations, power flow is first be solved using modified versions of the distributed slack bus Newton-Raphson (NR) power flow problem to find initial conditions. Followed by both primary controlled open-loop simulations with a three bus microgrid, and secondary controlled closed-loop simulations on the same system. Finally, we present how the systems react to disturbances, and then outline a plan for further testing.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Roberts, T.G.

Contributors dc:contributor

• Dominguez-Garcia, Alejandro D

• Grid Forming Inverter
• Dispatchable virtual oscillator control
• dvoc
• secondary frequency control
• secondary voltage control
• power systems

Statement dc:rights

• Copyright 2022 T.G. Roberts

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/115803

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F115803