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

Segmented permanent magnet ring generator with active damping of axial oscillations

This paper presents the design and control structure of a synchronous generator in ring form. The analysed generator is designed in order to test the control structure of a light-weight 10 MW generator for wind turbines. A segmented stator structure with distributed control allows control of the current of single stator segments which facilitates damping of axial displacement due to varying wind speeds by controlling axial forces. The layout process of the generator, its distributed control and the damping control are presented in this paper

Design Considerations for the Electrical Power Supply of Future Civil Aircraft with Active High-Lift Systems

Active high-lift systems of future civil aircraft allow noise reduction and the use of shorter runways. Powering high-lift systems electrically have a strong impact on the design requirements for the electrical power supply of the aircraft. The active high-lift system of the reference aircraft design considered in this paper consists of a flexible leading-edge device together with a combination of boundary-layer suction and Coanda-jet blowing. Electrically driven compressors distributed along the aircraft wings provide the required mass flow of pressurized air. Their additional loads significantly increase the electric power demand during take-off and landing, which is commonly provided by electric generators attached to the aircraft engines. The focus of the present study is a feasibility assessment of alternative electric power supply concepts to unburden or eliminate the generator coupled to the aircraft engine. For this purpose, two different concepts using either fuel cells or batteries are outlined and evaluated in terms of weight, efficiency, and technology availability. The most promising, but least developed alternative to the engine-powered electric generator is the usage of fuel cells. The advantages are high power density and short refueling time, compared to the battery storage concept

Groves Mechanism vs. Profit Sharing for Corporate Budgeting - An Experimental Analysis with Preplay Communication

This paper experimentally explores the efficiency of the Groves mechanism and a profit sharing scheme in a corporate budgeting context. Specifically, it examines the effects of anonymous communication on both incentive schemes. The results show that although the Groves mechanism is analytically superior to the profit sharing scheme, the latter turns out to be advantageous for headquarters in our experiment. This is essentially due to the effects of communication on both incentive schemes. Under the profit sharing scheme, communication improves coordination and reduces inefficient resource allocation. Under the Groves mechanism, however, it leads to stable collusion strategies of the participants, and thus increases compensation costs.