This paper presents an analysis of iron losses for an inverter-fed permanent synchronous electric machine. The iron loss computation is based on the coupling between an analytical inverter model and a 2D finite element simulation. For theoretical explanation of the considered effects the magneto motive force of the machine with non-sinusoidal supply is derived. These impacts are analyzed in detail for one operating point, while using two different iron loss models. It is shown that the iron losses are much higher with inverter supply caused by high harmonic flux content in the rotor finite elements. At the end the iron losses for the whole operating range are computed to verify the single point calculation.