Project Title: Dynamic Behavior of a Power Electronic based System Analysis through Virtual Impedance Method
PhD period: 2017.11.01 – 2020.10.31.
Section: Power Electronic Systems
Research Programme: Efficient and Reliable Power Electronics
Supervisor: Xiongfei Wang
Co-Supervisor: Donghua Pan
Collaborator: To be announced later.
Funding: China Scholarship Council (CSC) and Department of Energy Technology.
Due to the increasing integration of renewable energy resources, such as wind and solar energy, more and more sensitive loads show up in the system. This incurs some severe problems in power system stability and power quality which endanger the safety operation of whole system. So, the influence of the power electronic within the power system will need to analyze in order to fulfil the requirement of system stability. The main objective of the project is, the dynamic behavior of a power electronic based system should be analyzed by using virtual impedance method. Due to the combined effects between passive components as cables, LCL filter and control mode of electronic devices, the harmonic resonances would be generated in system with high penetration of power electronic devices. In order to identify the resonance, the impedance based resonance analysis method will be adopted in this project. By obtaining the transfer function of such a system through impedance based method, the small signal stability of the system can be easily well analyzed which is the basis for harmonic resonance mitigation. By considering linearizing the models of inner control loops of both sides converters, the harmonic stability of a multiple input multiple output (MIMO) control system can be identified while the mitigation will mainly be focused on stability analysis of single grid converters and multiple converters by using virtual impedance control method. After the shaping of the virtual impedance. The outer virtual impedance will be used for mitigating grid synchronization instability and inner virtual impedance for mitigating current control instability. Besides harmonic content, the power quality related transient voltages and current, and variation in voltage magnitude also need to be studied in the experiment.
Publications in journals and conference papers may be found at VBN.