Alexander Kock

Evaluation of an efficiency-optimized calculation of PM synchronous machines' operating range using time-saving numerical and analytical coupling

In this paper, a new method for an accurate and also time-saving calculation of permanent magnet synchronous machines is presented. The method is based on a coupled numerical-analytical approach. The aim is to determine efficiency optimized torque-speed characteristics of the drive system. The novel approach considers all kinds of losses, such as switching and conduction losses of the inverter, copper losses, friction losses as well as saturation-dependent hysteresis and eddy current losses of the electrical machine. The presented approach is verified by measurements of a high-torque wheel hub drive.

Fault tolerant wheel hub drive with integrated converter for electric vehicle applications

In this paper, a wheel hub drive with high torque capability and increased fault tolerance is presented. The general drive concept and the special requirements of a fault tolerant design are described. The operational behavior of the drive system in normal mode and fault mode is shown on a motor test bench.

Casting production of coils for electrical machines

The presented method for casting production of coils for electrical machines offers significant advantages over conventional production methods in terms of achievable performance, torque density, and the production costs of electrical machines. Below, the outline of the procedure is presented in accordance with electrical and constructive conditions. Based on initial casting experiments, the principle feasibility of the method is demonstrated.

Modeling and control of fault tolerant drive topologies for electric vehicle applications

In this paper, fault tolerant topologies based on permanent magnet synchronous machines (PMSM) are presented. A numerical model for the simulation of the operational behaviour under normal and fault conditions is developed and validated by test bench measurements. For different fault tolerant topologies, control strategies for normal and post-fault operation are presented and validated by measurements and simulations. In post-fault operation, the presented control-strategies allow the compensation of braking torques and to avoid overvoltages at the machine terminals. In normal operation, the additional degrees of freedom are utilized to improve operational behaviour in various aspects.

Cast coils for electrical machines and their application in automotive and industrial drive systems

The casting production of coils for electrical machines is an innovative approach that offers significant advantages over conventional production methods in terms of achievable performance, torque density, and the thermal behaviour of electrical machines. Slot filling factors up to 90 % can be reached, whereas the production cost can be reduced due to good automation capability. On the other hand the cast coils are solid conductors which might lead to additional losses especially at high operating frequencies. In this paper, the electromagnetic and thermal characteristics of cast coils are presented. Two examples for automotive and industrial applications are shown.