Physical Parameter Estimation for a Two-Level VSI Three-Phase PMSM Electric Drivetrain

A methodology for computing the physical parameters of a two-level VSI three-phase PMSM drivetrain is described. The method uses a load test at constant speed, and lumps resistive voltage drop, core loss resistance, and inverter nonlinearity together. Motor inductance, flux offset, and drivetrain resistance are calculated for a group of setpoints. The method uses a constant speed load test with only current sensors and a position sensor, and overcomes the rank deficiency problem by including adjacent points in an overdetermined unconstrained least squares minimization problem. Results demonstrate satisfactory physical parameter estimation with a 15% increase in airgap torque estimation accuracy compared to nameplate while withstanding a robustness to ±20% speed errors and ±10% current space harmonics.