Offline Inductance Identification of IPMSM With Sequence-Pulse Injection

Identification of the stator <italic>d</italic>-axis and <italic>q</italic>-axis inductances is essential for the interior permanent magnet synchronous motor (IPMSM) sensorless control system. The signal injection method is an effective way to identify the inductance parameters; however, it requires the rotor position to ensure the accuracy of the injection reference position. To overcome the dependence on the rotor position, a sequence-pulse voltage signal injection method is presented. The matrix least-squares fitting algorithm is utilized to fit the current responses for the inductance identification. Based on the fitting method, the discrete standard orthogonal polynomial with look-up table is introduced to reduce the computation complexity. To reduce the disturbance of the injected signal to the rotor position during the identification process, a double-direction injection position trajectory planning is presented. In addition, the saturation effect on the identification method is also analyzed. The proposed method is verified via a 3.0 kW IPMSM motor drive platform. The identification results are compared with those measured by a standard method and experiment results show that the proposed method can identify the inductance parameters with acceptable accuracy without obtaining the rotor position information.