Control and operation of a DC microgrid-II

• Main Author: Lai, Xue Lim
• Other Authors: Sun Changqing
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/63586
• Institution: Nanyang Technological University

With the ongoing and increasing popularity of DC-compatible loads, distributed renewable energy sources has recently attracted significant interest and attention, calling for the need to develop power electronic converters that boost applications of DC microgrids. Not only does the evolution of DC microgrids greatly eliminate energy wastages associated with transmission and distribution losses, it allows efficient management and control of distributed renewable energy sources, power electronic converters, battery energy storages, and loads. An excellent example of renewable energy source is solar photovoltaic, which are commonly installed as power sources with Boost converters at the output to facilitate active voltage regulation in DC microgrid. With battery energy storage, it addresses the problem of irregular solar irradiation throughout the day. By compensating for the energy deficit in the absence of sunlight, it ensures that there is a constant energy supply. Proper control algorithms and protection for autonomous operation of DC microgrid coordinates the operation battery energy storage and solar photovoltaic. A study of this was carried out using MATLAB simulation models, and results are recorded in this report. To build the algorithms, the Monitoring Bus algorithms was first implemented on a bidirectional DC/DC converter to regulate output voltage to a desired value. The Maximum Power Tracking algorithm was then implemented to harvest the maximum possible power from a solar photovoltaic based on the Perturb and Observed theory. Multi-modes Control algorithms was then built to alternate between these two algorithms, depending on priority. The last step, is the integration of all algorithms to form Multi-level DC microgrid, which will then be tested using the DSpace Control Desk virtual instrument. The Multi-level DC microgrid operation assigns sub-regions based on the DC bus voltage. In the different regions, the system elements will be ranked different priorities, and they will be scheduled accordingly to regulate the DC bus voltage. Different operation modes of the system elements will also be activated depending on the DC bus voltage.