An observer for the estimation of the inductance harmonics in a permanent-magnet synchronous machine

It is well-known that buried permanent-magnet synchronous machines have inductances with high-order harmonics. These inductance variations are due to nonsinusoidal field distributions and lead to torque pulsations. In this paper, we use an observer to estimate these harmonics. The effectiveness of the proposed method is investigated through computer simulations, and experimental results highlight the necessity to consider high-order harmonics.