Impedance Matrix and Parameters Measurement Research for Long Primary Double-Sided Linear Induction Motor

Static longitudinal end effect caused by truncated iron and coil windings is the inherent characteristic of linear motors. For multisegment long primary double-sided linear induction motors (DLIMs), subsection power supply mode results in longer iron than excited coil windings, which aggravates the static longitudinal end effect. First, the characteristics of the DLIM impedance matrix are researched through experiments. The impedance matrix is calculated by the measured amplitude and phase of the three-phase voltage and current. Unlike the traditional rotating induction motor, the matrix of DLIM is not a traditional cyclic symmetric matrix. Positive-sequence impedance, which is defined and obtained based on the impedance matrix, could be used to measure parameters by open-circuit and short-circuit experiments. The parameters measurement method is validated more accurate than the traditional average phase impedance. The research results, which are validated by test data from the long primary DLIM system capable of producing 400 kN of force, operating at the 100-MW peak power level, could be the reference for accurate description of the dynamics motor model and parameter measurement.