Application of planar modular windings to linear induction motors by harmonic cancellation

The magnetomotive force (mmf) of a modular planar winding contains multiple distinct waveforms which travel in opposite directions. An inductive rotor will produce oppositional forces from both waveforms, giving a poor overall performance. This study concerns the use of planar modular windings in linear induction motors by harmonic cancellation. A double-sided arrangement of stators is used and a mechanical offset is applied between the two stators such that the fundamental mmf waveform is reinforced and the oppositional harmonic mmf waveform is suppressed. A comprehensive mathematical analysis of mmf harmonic behaviour in the offset machines has been developed. Further, a high-speed dynamic test rig has been produced, which verifies the excellent performance of the offset modular configuration.