The number of power electronic converters is increasing in the grid due to favourable political climates regarding renewable energy resources. Grid-parallel inverters have been shown to suffer from reliability problems that may not be solved with pure time domain analysis. Therefore, it is important to analyse the dynamics of these converters also in the frequency domain. This paper reviews small-signal modelling method of three-phase converters and proposes a measurement setup utilizing digital signal processing, which can be used to verify the small-signal model. Experimental measurements from a three-phase photovoltaic inverter will be presented. (6 pages)