Optimized Pulse Patterns for Synchronous Machines with Non-Sinusoidal Back-EMF

Permanent magnet synchronous machines (PMSMs) used in automotive applications typically have a small number of stator slots. This distorts the air- gap flux distribution, thus resulting in a non-sinusoidal back-electromotive force (back-EMF), which in turn deteriorates the drive performance and decreases its efficiency. To address this, this paper proposes optimized pulse patterns (OPPs) that account for the back-EMF harmonics. In doing so, the computed OPPs can significantly improve the drive performance in terms of current and torque distortions. The presented numerical results verify the effectiveness of the proposed modulation method.