A Hybrid Polygonal Space Vector Modulation Scheme for an Induction Motor Drive

Polygonal voltage space vector structures are known to improve output voltage quality in full speed range of induction motor drive. A hybrid space vector consists of more than one type of polygons in the resultant voltage space vector structure. A novel hybrid multilevel polygonal structure consisting of dodecagonal and 24-sided polygonal structure for induction motor with open end winding (OEIM) is proposed in this paper. The proposed structure consists of 48 active vectors and a null vector. The proposed scheme eliminates
$6\mathbf{n}\pm 1$
(n = odd number) order harmonics from output voltage in linear range of operation. Higher order harmonics in output voltage are highly suppressed with the help of multilevel structure of the proposed scheme. The method eliminates
$6\mathbf{n}\pm1$
(n = odd number) and
$12\mathbf{n}\pm 1(\mathbf{n}=$
odd number) order harmonics from output voltage in 24-step operation. Detailed experimental verification is performed on laboratory prototype of 10 kW. Switching losses and weighted total harmonic distortion (WTHD) are compared with other schemes in literature to prove effectiveness of the proposed scheme.