Second-Order Sliding-Mode Control Applied to Microgrids: DC AC Buck Converters Powering Constant Power Loads

Microgrids are designed to connect different types of AC and DC loads, which require robust power controllers to achieve an efficient power transfer. However, the effects of both AC and DC disturbances in the same type of controller make achieving stability a design challenge, especially in coupled...

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Bibliographic Details
Published inEnergies (Basel) Vol. 17; no. 11; p. 2701
Main Authors Monsalve-Rueda, Miguel, Candelo-Becerra, John E, Hoyos, Fredy E
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.06.2024
Subjects
Analysis
buck converter
Buses
constant power load
Controllers
Design
Electric current converters
microgrid
power converter
Robust control
sliding-mode control
Systems stability
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Summary:Microgrids are designed to connect different types of AC and DC loads, which require robust power controllers to achieve an efficient power transfer. However, the effects of both AC and DC disturbances in the same type of controller make achieving stability a design challenge, especially in coupled systems where disturbances affect both the upstream and downstream in the microgrid. This paper presents an analysis of a second-order sliding-mode control (SOSMC) applied to a microgrid with direct-current (DC) and alternating-current (AC) power converters. The aim is to simulate the second-order sliding-mode control with buck converters that feed constant DC–DC and DC–AC power loads. The controller was tested in consideration of a unique sliding surface facing external disturbances, such as variations in the frequency of AC converters, sudden changes in upstream voltages, and constant power loads (CPL). The influence of the gain values (K) on the controller was also analyzed. The results show that the controller is robust regarding its sensitivity to external disturbances and steady-state error. However, the importance of the constant “K” in the model states that there exist K-limit values where if “K” is too low, a slowdown is presented, and the response against disturbances can be critical, and if is too high, an overshoot is presented in the output voltage.
ISSN:1996-1073
1996-1073
DOI:10.3390/en17112701