The design and simulation of a new three-phase axial flux generator have been performed. The generator is a permanent magnet machine (PMG) and consists of two rotors at two sides and a stator at the middle. In the machine, each rotor has 16 rare earth disc-type magnets and back-iron units and the stator at the middle has 24 coils. It has been understood that the generator produces directly sinusoidal output and requires no conversion in the wave shape. The 3D simulations have been performed via the finite element analysis (FEA) method by the magnetostatic and magnetodynamic tools. It has been found that the machine generates 3.4 kW at 1000 rpm for the air gap of 1.5 mm. This gives the power density of 336 kW/m(3) for the rated value of the generator and it is higher than the power densities of many axial flux generators in the literature. The maximal cogging torque value has been estimated as 3.6 Nm, which is a good value for a back-iron machine. It has been also proven that the waveform harmonics become lower at higher rotor speeds. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.