Online identification of a two-mass system in frequency domain using a Kalman filter

Some of the most widely recognized online parameter estimation techniques used in different servomechanism are the extended Kalman filter (EKF) and recursive least squares (RLS) methods. Without loss of generality, these methods are based on a prior knowledge of the model structure of the system to be identified, and thus, they can be regarded as parametric identification methods. This paper proposes an on-line non-parametric frequency response identification routine that is based on a fixed-coefficient Kalman filter, which is configured to perform like a Fourier transform. The approach exploits the knowledge of the excitation signal by updating the Kalman filter gains with the known time-varying frequency of chirp signal. The experimental results demonstrate the effectiveness of the proposed online identification method to estimate a non-parametric model of the closed loop controlled servomechanism in a selected band of frequencies

High-speed Electrical Machine with Active Magnetic Bearing System Optimization

High-speed (HS) electrical machines provide high system efficiency, compact design, and low material consumption. Active Magnetic Bearings (AMBs) bring additional benefits to the high-speed system, such as elimination of the friction losses, reduced wear and maintenance, and a built-in monitoring system. High-speed drivetrains are usually designed for specific applications and require a high level of integration. This paper describes a design method of the HS electrical machine supported by AMBs, considering their mutual influence on the system performance. The optimization procedure, which takes into account both the electrical machine and bearing designs is developed. The optimization is based on a multiobjective differential evolution (DE) algorithm. The selected optimization parameters include the AMB and machine dimensions. The optimization objectives cover the electrical machine performance and the rotordynamics. The results of the proposed optimization algorithm are implemented in the constructed 350kW, 15000rpm induction machine with a solid rotor supported by AMBs. The prototype tests verify the design and optimization results.Peer reviewe

Modelling and Model-Based Control of A Bearingless 100 kW Electric Motor for High-Speed Applications

DOI puuttuu / mmThis paper presents model-based control (MBC) analyses of a bearingless interior permanent magnet motor (IPMM). The motor is capable of producing 100 kW power for use in high-speed applications in industries. The maximum speed of the motor is 22000 rpm. Motor’s initial parameters are obtained through Finite Element Method (FEM) analyses. State-space models, controller and observer matrices are built based on the optimal, operating points obtained from FEM analyses. Thereafter, the rotor’s magnetic levitation characteristics are analyzed through digital control strategies. Performances of the controlled system are recorded and subsequently discussed.Peer reviewe

Haplotype analysis in Icelandic and Finnish BRCA2 999del5 breast cancer families

The 999del5 mutation is the single, strong BRCA2 founder mutation in Iceland and the most common BRCA1/2 founder mutation in Finland. To evaluate the origin and time since spreading of the 999del5 mutation in Iceland and in Finland, we constructed haplotypes with polymorphic markers within and flanking the BRCA2 gene in a set of 18 Icelandic and 10 Finnish 999del5 breast cancer families. All Icelandic families analysed shared a common core haplotype of about 1.7 cM. The common ancestors for the Icelandic families studied were estimated to trace back to 340-1000 years, not excluding the possibility that the mutation was brought to Iceland during the settlement of the country. Analysis of the Finnish families revealed two distinct haplotypes. A rare one, found in three families in the old settlement region in southwestern Finland, shared a four-marker (0.5 cM) core haplotype with the Icelandic 999del5 haplotype. A distinct approximately 6 cM haplotype was shared by seven 999del5 Finnish families estimated to have a common ancestry 140-300 years ago. These families cluster in two geographical regions in Finland, in the very same area as those with the rare haplotype and also in the most eastern, late settlement region of Finland. The results may indicate a common ancient origin for the 999del5 mutation in Iceland and in Finland, but distinct mutational events cannot be ruled out. The surprising finding of the same mutation in two completely different haplotypes in a sparsely populated area in Finland may suggest gene conversion