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Solid State Transformers (SSTs) are being considered as a replacement to the classic transformers especially for renewable energy and energy storage systems mainly due to their much smaller size and controllability and regulation over the transferred power. Multi-Port SSTs share one high frequency core for the isolation between several devices and hence are even more compact and efficient but the system is complex and the control of such a system is a challenge. This paper considers a four-port, MPSST connected to a renewable source, battery, load, and the grid and discusses various scenarios and operating points. It is shown that several factors including the ratio of the renewable power to the load, battery SOC status and role of the battery in the system change the desired power flow in the system and there are several control structure needed for each mode of operation. These modes of operation and the boundary between them are recognized and eventually a MIMO control scheme is suggested that includes several switches to changes the structure of the controller to adjust the controller structure to the operating condition. Eventually, input-output linearization technique has been adopted to the system to linearize the model and achieve a better control performance.
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Sliding Mode Control Based Energy Harvesting System For Low Power Applications
As technology advances and cities become more innovative, the need to harvest energy to power intelligent devices at remote locations, such as wireless sensors, is increasing. This paper focuses on studying and simulating an energy management system (EMS) for energy harvesting with a battery and a supercapacitor for low power applications. Lithium-ion batteries are the primary energy storage source for low power applications due to their high energy density and efficiency. On the other hand, the supercapacitors excel in fast charge and discharge. Furthermore, supercapacitors tolerate high currents due to their low equivalent series resistance (ESR). The supercapacitor in the system increases the time response of the power delivery to the load, and it also absorbs the high currents in the system. Moreover, the supercapacitor covers short-time load demand due to the fluctuation of the renewable source. The EMS monitors the proposed system to maintain power to the load either from the renewable source or the energy storage. The power flow of the energy storage is controlled via DC-DC bidirectional converters. The lithium-ion battery is charged via a constant current (CC) using a sliding mode controller (SMC) and a constant voltage (CV) via a typical PI controller. The response of the SMC current controller is compared with PI and Fuzzy current controller. Furthermore, the performance of a system having and not having a supercapacitor is compared. Finally, MATLAB modeling system simulation and experimental implementation results are analyzed and presented.
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- Award ID(s):
- 1816197
- PAR ID:
- 10330603
- Date Published:
- Journal Name:
- IEEE Energy Conversion Congress & Expo 2021
- Page Range / eLocation ID:
- 302 to 309
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/ECCE47101.2021.9595302
