The methodology for the nonlinear modelling and analysis of active magnetic bearing (AMB) systems in the harmonic domain (HD) is presented. This approach is based on the HD linearisation of the AMB system around nonlinear stationary solutions at different rotating speeds. The main advantage obtained is the representation of the periodic LTV models that describe the steady-state dynamics for each speed, by means of LTI models in the HD. In order to show its possibilities, the proposed approach is applied to an AMB laboratory testbed based on the MBC500 Rotor Dynamics from Launchpoint Technologies. This analysis explains the nonlinear nature of the response that appears at high speeds, due to the large oscillations introduced by the shaft unbalance, and detects a low-frequency gain loss when increasing the rotating speed. This phenomenon causes the instability of the system, leading to destructive crashes. In addition, the analysis allows to take into account the effect of the delay introduced by the calculation time in the system behaviour when the controller is implemented by using digital devices.

This article describes the design of a high performance 2-DOF controller for an electromechanical system consisting of a rotary flexible spindle hovered by Active Magnetic Bearings (AMB). The purpose of such a controller is to achieve the better positioning possible of the spindle by means of a good stabilization mechanism and by counteracting the vibrations generated naturally by the rotation. The implementation of this controller is based on three main blocks, a stabilization block, a vibration minimization block and, if needed, a dynamics decoupler block between the previous ones. The stabilization controller is designed utilizing a MIMO decoupling technique. With the aim of proving its effectiveness, two different stabilization controllers (PID and H_∞) are presented. On the other hand, an adaptive feedforward algorithm which is in charge of the vibration minimization is implemented. In order to not feedback the vibration and, therefore, to decouple the controller's dynamics, the implementation of a variable Notch filter is discussed. It is demonstrated that this optional block can enhance or impoverish the behavior of the system depending on several factors such as resonances or rotational speed measurement. Experimental results and simulations are provided to show the effectiveness of the complete design process.

A new compact linear proton accelerator project (named LINAC 7) for multiple low-current applications, designed and built in-house at the Beam Laboratory of the University of the Basque Country (UPV/EHU) is described. The project combines the University, a research technology center and a private company with the aim of designing and building a compact, low-current proton accelerator capable of accelerating particles up to 7 MeV. In this paper, we present an overview of the accelerator design, summarize the progress and testing of the components that have been built, and describe the components that are being designed that will allow us to achieve the final desired energy of 7 MeV.

The baseline design for the ESS-Bilbao light-ion linear accelerator and neutron source has been completed and the normal conducting section of the linac is at present under construction. The machine has been designed to be compliant with ESS specifications following the international guidelines of such project as described in Ref. [1]. The new accelerator facility in Bilbao will serve as a base for support of activities on accelerator physics carried out in Spain and southern Europe in the frame of different ongoing international collaborations. Also, a number of applications have been envisaged in the new Bilbao facility for the outgoing light ion beams as well as from fast neutrons produced by low-energy neutroncapture targets, which are briefly described.