Performance of two 5 MW permanent magnet wind turbine generators using surface mounted and interior mounted magnets

This article presents a performance comparison of two permanent magnet synchronous generators for a wind turbine application. The difference is the placement of the magnets, in one case they are surface mounted (SPMSG) and in the other case they are put inside the rotor (interior mounted)(IPMSG). The same amount of magnets and copper and almost the same amount of iron has been used in both cases. Two different appropriate voltages have been used in order to broaden the investigation. The results show that the energy efficiency is higher for the IPMSG. The reason is a better power factor. For an average wind speed of 7 m/s, the energy efficiency was 99.3 % for the IPMSG and 99.1 % for the SPMSG using the dc-link voltage 2.23 kV and 99.1 % for the IPMSG and 99.0 % for the SPMSG using the dc-link voltage 1.72 kV. Moreover, as written above it was found that the efficiency is affected by the choice of dc-link voltage.