Sensorless flux model of induction machines using cross-saturation effects based on a virtual air gap

This paper presents a main flux oriented model of an induction machine which considers the saturation in both magnetizing and leakage inductances. The model is based on a virtual air gap. With this model it is possible to simulate the saturation characteristic and the cross-saturation effect. The validity of these results is proved with measurements on a test bench. A procedure is presented that shows the changes in cross-saturation by a test signal injection during standstill. The fitting machine model offers a new corresponding flux model without a position or speed sensor, which could identify the flux position by this cross-saturation influence.