Comparative study of the influence of harmonic voltage distortion on the efficiency of induction machines versus line start permanent magnet machines

Induction machines have nearly reached their maximal efficiency. In order to further increase the efficiency the use of permanent magnets in combination with the robust design of the induction machine is being extensively researched. These so-called line start permanent magnet machines have an increased efficiency in sine wave conditions in respect to standard induction machines, however the efficiency of these machines is less researched under distorted voltage conditions. This paper compares the influence of harmonic voltage distortion and the phase angle of the harmonic content on the overall motor efficiency of line start permanent magnet machines and induction machines.