Search Results

This paper reports on the analytical and experimental results for an 8/6 switched reluctance machine operating under conventional and bipolar excitation strategies. The results illustrate the relationship between normal and tangential flux densities present in the airgap, and normal and tangential force densities present on stator and rotor poles. The investigation utilizes finite element analysis in conjunction with the Maxwell Stress Tensor method to correlate the relationship between the radial and tangential force densities and the airgap flux densities. In addition, finite element analysis is utilized to illuminate the difference in flux path type between the conventional and bipolar excitation methods. The experimental results are presented in terms of electromagnetic torque production over a full electrical cycle for each excitation method.

There is a clear trend towards Hybrid Electric Vehicles (HEV) due to the environmental concerns. On the other hand, with increasing hotel and ancillary loads and replacement of more engine driven mechanical and hydraulic loads with electrical loads, automotive systems are becoming more electric. This is the concept of More Electric Cars (MEC) which necessitates going to a higher voltage such as 42V for conventional cars. Can the evaluation of the 42V MEC smoothly lead to the Hybrid Electric Vehicles (HEV) and More Electric Hybrid Vehicles (MEHV)? In this paper, we investigate the feasibility of 42V & 14+42V electrical power systems for MEHV. Technical issues of such a solution are explored in detail.

The purpose of this paper is to present an assessment of the negative impedance instability concept of the constant power loads in the More Electric Aircraft (MEA) power systems. We address the fundamental problems faced in the stability studies of these multi-converter power electronic systems. An approach to the design of sliding-mode controllers for PWM DC/DC converters with constant power loads is presented. Because of the negative impedance destabilizing characteristics of constant power loads, conventional linear control methods have stability limitations around the operating points. However, the proposed controllers improve large-signal stability and dynamic responses. The proposed controllers are simulated and their responses under different operations are discussed. Finally, we verify the stability of the controllers using the second theorem of Lyapunov.