In this study, an equivalent matrix structure of three-phase flying capacitor multilevel inverters (FCMIs) is developed. This structure is obtained by using a switching function for each voltage level. For one switching function, there is more than one combination of gate signal to produce each output voltages. Hence (3 n ) switching functions are defined for all switch combinations of the output voltage and their corresponding switch states. Therefore the modulation strategy of a three-phase FCMI is obtained in two steps. Firstly, the direct space-vector modulation of the matrix converter is used to compute the switching functions. The gates signals of the three-phase FCMI can be calculated by inversing the modelling part. In this work, the direct space-vector multilevel modulation based on the use of 2 n different three level functions called modulation functions is presented. Using this approach, the modulation strategy of a three-phase FCMI is designed without using a Park transform. To validate the effectiveness of the equivalent matrix structure modelling and control, simulation results are given for nine-level FCMI. Moreover, experimental results are given for a three-level neutral point clamped (NPC) converter prototype laboratory.