Dissertation Schuhmann
Dr.-Ing. Christian Schuhmann
"The double-sided axial flow machine with ironless rotor"
The investigation of novel concepts for electrical drive systems and the dimensioning of such systems is an essential research field because of the latest regulations and modified requirements. This work deals with the design of a double-fed axial-flux machine with an ironless rotor based on a system’s approach. The modelling of the machine is done by using analytical calculation schemes, which are verified by FEM-calculations and measurement results. The prototype of the machine has been designed in consequence of the results of comparisons of basic geometrical variants and different winding layouts. The Focus of these comparisons is the ironless rotor design. The rotor winding system consists of traces on a printed circuit board. Because of the use of a printed circuit board as the rotor of the machine, an integrated inverter on the rotor was realized. The rotor supply is done by using a contactless high-frequency energy transfer system. In addition to this, a optical communication interface between the stator- and rotor-electronics has been implemented to ensure the information exchange in the machine. To complete the system’s approach, a control agorithm has been designed, which is based on a sensorless field-oriented control up to standstill od the rotor. The control scheme is able to reduce the iron losses and doubles the speed range in comparison to a single-fed machine.