HARMONICS M arten Sj ostr om and Bertrand Dutoit Chair of Circuits and Systems, Swiss Federal Institute of Technology, 1015 Lausanne, Switzerland [email protected] Abstract| The classic Preisach model is used to describe a general hysteretic behaviour, and as most nonlinear systems, its output contains higher harmonics. A Fourier analysis of a speci c class of weighting functions for th...

Vibration damping in polycrystalline TbDy alloys was studied at cryogenic temperatures. Mechanical hysteretic losses were measured at various strains, frequencies, and loading configurations at 77 K. Some textured TbDy materials demonstrated 22.6% energy dissipation in mechanical measurements at low frequency ~0.01 Hz! and a mean logarithmic decrement of 0.23 at a higher frequency ~25 kHz!. Ult...

Hysteresis loops are phenomena that sometimes are encountered in the analysis of pharmacokinetic and pharmacodynamic relationships spanning from pre-clinical to clinical studies. When hysteresis occurs it provides insight into the complexity of drug action and disposition that can be encountered. Hysteresis loops suggest that the relationship between drug concentration and the effect being meas...

The demand for electricity from renewable sources continues to rise, and with it, the need for more efficient wind energy conversion systems. Wind turbines equipped with a wound-rotor induction machine can be operated in a more efficient configuration than currently popular, with little to no change in system hardware. By coupling the machine to the grid inversely to the norm, losses in the sys...

This paper presents 2D and 3D modeling of hysteresis motor using high temperature superconducting element Yttrium Barium Copper Oxide (YBCO) in the rotor. These hysteresis motors aim to improve the performance in comparison with that of conventional hysteresis motors. Various performance parameters of high temperature superconducting hysteresis motor are computed from the proposed 2D and 3D mod...

In this paper, a neural network based adaptive sliding mode control scheme for hysteretic systems is proposed. In this control scheme, a neural network model is utilized to describe the characteristic of hysteresis. Then, the adaptive neural sliding mode controller based on the proposed neural model is presented for a class of single-input nonlinear systems with unknown hysteresis. For the case...

In this study, a characterization of hysteresis in a piezoceramic stack actuator similar to those employed in an actively controlled flap (ACF) system is performed to assess the effects of hysteresis on system performance. The effect of unmodeled actuation hysteresis may significantly reduce vibration and noise reduction capabilities. A hysteresis model based on the classical Preisach model has...

Compared to mechanical bearings, active magnetic bearings eliminate friction, resulting in lower energy losses. However, due the magnetization characteristics and high-frequency working of core material bearing, there will be high wind friction loss, eddy current hysteresis loss copper bearing. These losses generate heat increase internal temperature which not only affect control accuracy beari...

In many scientific and medical applications wavefront-sensorless adaptive optics (AO) systems are used to correct the wavefront aberration by optimizing a certain target parameter, which is nonlinear with respect to the control signal to the deformable mirror (DM). Hysteresis is the most common nonlinearity of DMs, which can be corrected if the information about the hysteresis behavior is prese...

The origins of gate-induced hysteresis in carbon nanotube fi eld-effect transistors are explained and techniques to eliminate this hysteresis with encapsulating layers of methylsiloxane and modifi ed processes for nanotube growth are reported. A combined experimental and theoretical analysis of the dependence of hysteresis on the gate voltage sweep-rate reveals the locations, types, and densiti...