Date of Award
David Wenzhong Gao, Ph.D.
Control strategy, Microgrid, Model predictive control, PI controller
In the 21st century, because of the exhausting of oil, coal and other non-renewable energy, human beings enter a period of large-scale exploitation and utilization of renewable energy. Renewable energy generation become an important way for new energy utilization, however, as more and more distributed generation connect to power distribution network, the traditional distribution network structure will be changed. A large number of distributed generation applications of modern power electronic technology, have also produced a lot of harmonics to impact the power quality. It will threaten the safe operation of the distribution network and obstruct the utilization of renewable energy. The concept of microgrid provides a new thinking for the application of renewable energy. Microgrid can make full use of the characteristics of the renewable energy and it is the key of the future resources and environment for human beings. We can predict that, microgrid construction will be rapidly developed in 21st century, based on the utilization of renewable energy.
In order to coordinate the contradiction between power grid and distributed generation, the concept of microgrid arises at the historic moment. Microgrid has two operation modes: islanded mode and grid-connected mode. By theoretically analyzing, simulation model construction and result analyzing, the microgrid coordinated control strategies will be studied in this paper.
Firstly, this paper starts from the microgrid operation control mode, respectively establishing the traditional control strategy of simulation for the isolated and connected microgrid. The isolated grid control strategies is V/f control strategy based on droop characteristic and the connected grid control strategies is P/Q control strategy.
Second, the model predictive control is introduced in chapter three including its principle and application. In the case study, the traditional PI controller is compared with model predictive control controller in single distributed generation system to introduce advantages of model predictive control method.
Last, the model of microgrid with multiple distributed generations is built in MATLAB/Simulink. There are three cases in this model: working model switches between grid-connected and islanded mode; increase and decrease load in islanded mode; disconnect one PV system at certain time in islanded mode. By analyzing results of three cases, the MPC controller can achieve desirable efficiency of power control. Meanwhile, the voltage and frequency are working in the required range of the system. That proves the effectiveness of MPC controller.
Shen, Yitong, "Microgrid Control Strategy Study and Controller Design Based on Model Predictive Control" (2017). Electronic Theses and Dissertations. 1241.
Received from ProQuest