Mathematical modelling of an inverter-based distributed generator

Abstract

In this paper, a modeling approach of a three phase power inverter based on an electrostatic synchronous machine is presented. By the proposed approach, any inverter-based distributed generator in a microgrid can be replaced by an equivalent electrostatic machine. This paper aims to promote the use of the proposed modeling approach in the analysis of microgrid stability. Thanks to the proposed modeling approach, transient performances of on-grid operation of converter-based distributed generators could be easily analyzed by multi-machine models. Parameters of the equivalent synchronous electrostatic machine model are derived to achieve equivalence with the inverter model. Small signal models in the d-q synchronous reference frame of both the inverter and the machine are compared. An integrated simulation setup including the electrical power inverter with a sinusoidal Pulse Width Modulation scheme and the small signal models of both the inverter and the electrostatic machine is implemented. Simulation results are shown to validate the modeling approach.