Modeling and simulation of single phase PV inverters
Li, Jingbo (2025)
Kandidaatintyö
2025
School of Energy Systems, Sähkötekniikka
Kaikki oikeudet pidätetään.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2025051240257
https://urn.fi/URN:NBN:fi-fe2025051240257
Tiivistelmä
This paper investigates the design of a single-phase photovoltaic inverter. To accommodate applications such as industrial and commercial PV systems and electric vehicles, a full-bridge grid-connected inverter is adopted as the topological model. Compared to the half-bridge configuration, the full-bridge employs twice the number of switching devices. However, under identical switching current, it achieves double the output power. Consequently, the full-bridge topology is more suitable for high-power applications.
The control strategy adopted is the traditional Proportional-Integral dual closed-loop control, which means that two control loops are used simultaneously in the system: an inner loop and an outer loop. The inner loop usually controls the current. The current loop control strategy mainly focuses on the fast and accurate tracking of the current and usually adopts proportional-integral (PI) control. The design goal of the current loop is to ensure that the current can quickly follow the reference value while reducing the steady-state error. The outer loop controls the voltage or power. The voltage loop control strategy mainly focuses on the stability and accuracy of the output voltage. The voltage loop is generally located outside the current loop and is responsible for stabilizing the output voltage and reducing the steady-state error.
In this thesis, I designed and simulated a single-phase photovoltaic inverter with the aim of enhancing its suitability for industrial and commercial PV systems and electric vehicles. To achieve this, I selected a full-bridge grid-connected inverter as the topological model due to its higher power output compared to the half-bridge configuration. I implemented a traditional PI dual closed-loop control strategy, consisting of an inner current loop for accurate tracking and an outer voltage loop for output stability.
Using MATLAB/Simulink, I built a simulation model based on this full-bridge topology, incorporating appropriate SPWM signal generation and system parameters. I observed the voltage and current waveforms through the Scope module and conducted performance analyses under various conditions. By comparing the results with existing inverter parameters, I demonstrated that the proposed design offers improved output power and dynamic response, making it more suitable for high-power photovoltaic applications.
The control strategy adopted is the traditional Proportional-Integral dual closed-loop control, which means that two control loops are used simultaneously in the system: an inner loop and an outer loop. The inner loop usually controls the current. The current loop control strategy mainly focuses on the fast and accurate tracking of the current and usually adopts proportional-integral (PI) control. The design goal of the current loop is to ensure that the current can quickly follow the reference value while reducing the steady-state error. The outer loop controls the voltage or power. The voltage loop control strategy mainly focuses on the stability and accuracy of the output voltage. The voltage loop is generally located outside the current loop and is responsible for stabilizing the output voltage and reducing the steady-state error.
In this thesis, I designed and simulated a single-phase photovoltaic inverter with the aim of enhancing its suitability for industrial and commercial PV systems and electric vehicles. To achieve this, I selected a full-bridge grid-connected inverter as the topological model due to its higher power output compared to the half-bridge configuration. I implemented a traditional PI dual closed-loop control strategy, consisting of an inner current loop for accurate tracking and an outer voltage loop for output stability.
Using MATLAB/Simulink, I built a simulation model based on this full-bridge topology, incorporating appropriate SPWM signal generation and system parameters. I observed the voltage and current waveforms through the Scope module and conducted performance analyses under various conditions. By comparing the results with existing inverter parameters, I demonstrated that the proposed design offers improved output power and dynamic response, making it more suitable for high-power photovoltaic applications.