The target for net zero emissions in Australia and world-wide led to an increase of power electronic converter-interfaced generation facilities for integrating the renewable energy units. The downside of this rapid converter penetration is the diminishing essential power system stabilizing characteristics like inertia, fault current, oscillation damping etc. The modern power systems are incorporating virtual synchronous generators (VSGs) that mimic the behavior of the conventional synchronous generators through converter controls to tackle these problems.

A VSG control strategy comprises of nested control loops that models the synchronous generator principles, protection logics, and converter pulse width modulation (PWM) techniques. A proper VSG functioning is highly reliant on the design of various control loops and the interaction among the loops, failing which, the VSG along with the power system shall be prone to instability. For VSGs to support the power system stability needs, a detailed modelling, analysis and control design is vital.

In this thesis, firstly, the state-space equations of the VSG control loops like power control, voltage control, current control, and PWM stage are modelled along with the state equation of the converter filters and the upstream equivalent power system network. Rigorous procedures are performed to benchmark the developed model with that of the actual VSG response. Secondly, small signal model is derived to perform the eigen value analysis that alleviates the instability in grid-connected VSGs. The participation factor analysis of the eigen values is performed to identify the parameters that impact specific eigen values of its small signal model. This allows to zero-in on the control parameters that contribute to the instability of the VSG. Thirdly, a repetitive process of parameter tuning is performed by varying the critical control parameters in a way to lead the VSG to stable operation zone. The outcomes of the control tuning process are verified through simulation studies on Matlab/Simulink. The proposed process is a significant step towards developing appropriate control strategies for the VSG and thereby contributes to the overall power system stability.

The potential future work is to consider hybrid systems involving the VSGs and other renewable energy units like solar PV and wind energy systems, perform their modelling and control design for overall system stability.