Title

Frequency Domain Modeling And Optimal Parameter Tuning Of Power Converters For Dynamic Analysis Of The Grid Integration Of Photovoltaic Systems

Date of Award

4-2022

Degree Name

Doctor of Philosophy

Department

Electrical and Computer Engineering

First Advisor

Pablo Gomez, Ph.D.

Second Advisor

Richard Meyer, Ph.D.

Third Advisor

Damon Miller, Ph.D.

Keywords

Converters, domain, frequency, modeling, optmization, power

Abstract

Power electronic converters are essential devices for the effective interconnection of renewable energy sources to the power grid, such as DC-DC, DC-AC, and AC-DC converters. Therefore, power converter models that provide an accurate mathematical representation of their interconnection with other grid components are crucial for reliable transient and steady state analyses during normal or abnormal grid operating conditions.

This dissertation introduces a Laplace domain-based modeling approach for the study of transient converter-grid interactions. The proposed approach is based on the development of two-port admittance models of converters and other components, combined with the use of numerical Laplace transforms (NLT). The application of a frequency domain method is aimed at the accurate and straightforward computation of transient system responses while preserving the wideband frequency characteristics of power components, such as those due to the use of high frequency semiconductive switches, electromagnetic interaction between inductive and capacitive components, as well as wave propagation and frequency dependence in transmission systems.

Moreover, a procedure to find the optimal values of passive components (RLC) of DC-DC converters, inverters and filters is presented. Multi-objective optimization algorithms are used to tune the optimal parameters of DC-DC converters to minimize the objective functions of their transient response (rise time, settling time, and overshoot) for the output voltage and inductor current, while preserving their appropriate steady state performance. In addition, an optimization algorithm based on single objective with condition is used to tune the optimal parameters of the LCL filter used for grid connected inverters in PV application; the objective in this case is to minimize the transient overshoot and steady-state ripple of the voltage and current.

Finally, the developed models are evaluated by means of several test cases, comparing their results with those obtained using well-known commercial software EMTP-RV. The results obtained demonstrate the accuracy of the proposed approach to produce accurate transient voltage and current responses including different frequency components for a variety of scenarios and operating conditions. Regarding the optimization procedure, it is shown that the use of different optimization algorithms impacts the results in terms of minimizing the transient voltage and current stresses while preserving an appropriate performance during steady state.

Access Setting

Dissertation-Abstract Only

Restricted to Campus until

4-1-2023

Previous Versions

Oct 27 2022

This document is currently not available here.

Share

COinS