Lu, Jinghang

PROJECT TITLE: Power Quality Improvement in microgrid

PhD period: 2016.01.01 - 2018.12.31.
Section: Power Electronic Systems
Research Programme: Microgids
Supervisor: Josep Guerrero
Co-Supervisors: Mehdi Savaghebi and Yajuan Guan 
Contact information

Collaboration: China Scholarship Council.
Funding: China Scholarship Council and ET Scholarship.


With the increasing penetration of unbalanced and nonlinear loads into distribution system, stable operation of power distribution system suffers challenge by various power quality issues such as voltage unbalance and harmonic propagation. However, until now power quality improvement of multi-buses along the distribution feeder by coordinating control of multiple DG units in microgrid has not been well investigated. Power electronic converters, due to flexible operation, is capable of compensating voltage unbalance and harmonic by adding the compensation algorithm in the control loop.  As is shown in Fig.1, a group of power electronic converters with DG units consists of a micro grid, where local loads and critical loads are connected at the installation point and PCC point. Voltage unbalance and harmonic resonance that are caused by these local loads and critical loads may be propagated and amplified on the multiple buses along the feeder. Therefore, it is essential to mitigate the harmonic and unbalance voltage on multi-buses along the feeder and improve power quality of overall system. 

In this project, study will focus on harmonic mitigation and unbalance voltage compensation separately. transmission line theories and Smith Chart are introduced for analysing the unbalanced and harmonic propagation. Moreover, virtual impedance based algorithms, multi-objective optimization and global optimization methods will be carried out as well for improving the power quality of overall system.   

Fig.1 Illustration of Microgrid Operation


Publications in journals and conference papers may be found at VBN.