Improvement of Transient Power Sharing Performance in Parallel Converter System and Microgrids

This Ph.D. project proposes an alternative way of designing the microgrid (MG) control
structure. It takes advantage of the fast evolution of digital signal processors,
which is a platform for the integration of control algorithms for power
converters and drive applications. The key idea is to use that raw processing
power to embed all the inner control loops within a single algorithm that takes into account the model of the converter and its associated filter. In that
sense, the principle of using a discrete model of the voltage source converter
with an associated filter to predict its future behaviour for all possible control
inputs, and consequently applying the one that minimizes a programmed
cost function (CF) at every sampling time will be deployed. This kind of
control strategy is referred to as the finite control set (FCS) model predictive
control (MPC). Due to its flexibility and inherently fast response, such principle
has been widely and successfully applied to individual converters in
applications characterized by a high electromotive force, e.g. motor drives
applications. However, this method has not fully explored and investigated
in MG applications. This project aims to fill this gap both by theoretical research
and experimental demonstration, which will be developed to study
various aspects of the problem. Moreover, investigating the performance of
the proposed control structure in parallel operation is one of the main goals
of this project. Also, the effect on power quality has been addressed and the
feasibility of applying FCS-MPC control strategy is further studied through
efficiency analysis. Based on that, improved control strategies have been proposed
and presented in this thesis to ensure high quality and fast operation
of the future MGs.
Finally, this thesis seeks to answer some questions, which are related to
the performance of different control strategies of a typical VSC to be employed
in the MG operations. Also, the study seeks to leave the door open
for other researchers to increase the feasibility of the proposed solutions and
provide extra investigations.