In the framework of the European project ModulED (Modular Electric Drivetrain), CEA investigates the integration in a motor drive inverter of a recent but promising semiconductor technology, Gallium Nitride (GaN) power device. This inverter aims at powering a new generation of multiphase high speed motor1. On one hand, GaN device allows fast switching, and so frequency increase becomes possible. It allows reducing the size of passive components and results in very efficient switching performance. On the other hand, low on-state resistance enables low conduction losses. All combined, the good use of such GaN device in a motor for E-Drive leads to very efficient and compact inverter. This GaN motor drive inverter has led us to examine the impact of the DC-Bus capacitance implementation. The sizing of such a DC link differs from methods used for Silicon (Si) or Silicon Carbide (SiC) devices. This work is based on the confrontation of circuit simulation, physical characterization and experimental measurements. © VDE VERLAG GMBH · Berlin · Offenbach.