Real-time Electrical Emulation of Li-ion Battery Storage Using Power-Hardware-in-the-Loop
Leinonen, Joona (2019)
Leinonen, Joona
2019
Sähkötekniikan DI-ohjelma - Degree Programme in Electrical Engineering
Informaatioteknologian ja viestinnän tiedekunta - Faculty of Information Technology and Communication Sciences
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Hyväksymispäivämäärä
2019-07-03
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-201907012371
https://urn.fi/URN:NBN:fi:tuni-201907012371
Tiivistelmä
Li-ion batteries have become increasingly important in several engineering fields
of technology. The batteries play a crucial role, for example, in renewable energy
applications in which battery storages are used to balance the power fluctuations
caused by continuously varying weather conditions. Another good example is electric
vehicles whose operation is most often dependent on Li-ion batteries.
The ever-increasing applications of Li-ion batteries have set new challenges in battery
analysis. In order to know when the battery must be replaced and in which
application it might still be utilized, knowing the age of the battery is crucial. The
battery state of health (SoH) is used to estimate the aging and degradation of the
battery. The SoH can be estimated by measuring the battery internal impedance
since it is highly dependent on the aging processes.
Studying the battery aging is time-consuming because of the slow aging mechanisms
and charging or discharging the battery to the desired operating state. This thesis
studies methods for emulating the battery aging in real time using power-hardware-in-
the-loop environment. The methods make it possible to analyze the SoH of Li-ion
batteries within a short time without utilizing the actual aging process.
This thesis presents the modeling of Li-ion battery impedance and the implementation
of battery emulation. The battery impedance model parameters are extracted
from real data using a complex nonlinear least squares algorithm. Battery aging
models are used to vary the battery SoH in real time. The operation of the emulation
setup is verified by impedance measurements using wideband-identification
techniques.
of technology. The batteries play a crucial role, for example, in renewable energy
applications in which battery storages are used to balance the power fluctuations
caused by continuously varying weather conditions. Another good example is electric
vehicles whose operation is most often dependent on Li-ion batteries.
The ever-increasing applications of Li-ion batteries have set new challenges in battery
analysis. In order to know when the battery must be replaced and in which
application it might still be utilized, knowing the age of the battery is crucial. The
battery state of health (SoH) is used to estimate the aging and degradation of the
battery. The SoH can be estimated by measuring the battery internal impedance
since it is highly dependent on the aging processes.
Studying the battery aging is time-consuming because of the slow aging mechanisms
and charging or discharging the battery to the desired operating state. This thesis
studies methods for emulating the battery aging in real time using power-hardware-in-
the-loop environment. The methods make it possible to analyze the SoH of Li-ion
batteries within a short time without utilizing the actual aging process.
This thesis presents the modeling of Li-ion battery impedance and the implementation
of battery emulation. The battery impedance model parameters are extracted
from real data using a complex nonlinear least squares algorithm. Battery aging
models are used to vary the battery SoH in real time. The operation of the emulation
setup is verified by impedance measurements using wideband-identification
techniques.