Synchronous Optimal Pulsewidth Modulation for Synchronous Machines With Highly Operating Point Dependent Magnetic Anisotropy

The performance of synchronous optimal pulsewidth modulation is investigated for the control of an automotive low voltage electrical drive system, which consists of a two-level voltage source inverter and an interior permanent magnet synchronous motor. The machine magnetic anisotropy varies due to magnetic saturation and cross-saturation effects and depends on the motor operating point. The main objective of this article is to investigate the influence of the varying magnetic anisotropy on the optimized half-wave symmetric inverter pulse patterns. For this purpose, the optimized inverter switching angles are derived by minimizing the current harmonic distortion of an isotropic and anisotropic permanent magnet synchronous motor. Their performance is evaluated and compared by experimental results.