A novel estimation of phase currents from DC link for permanent magnet AC motors

This paper proposes a novel three-phase current reconstruction technique that utilises the measured DC link current and the switching signals of the inverter. The method is based on an adaptive current observer, which uses the computer model of the motor drive to determine all possible inverter conditions that are not measurable and reconstructs the phase currents accurately. A wide range of experimental results provided in this study demonstrates that the, method can accurately reconstruct the line currents of both trapezoidal and sinusoidal permanent magnet (PM) AC motors. The effects of parameter variations are also discussed.