Concept study of 20 MW high-speed permanent magnet synchronous motor for marine propulsion

High-speed permanent magnet synchronous machines are of great interest in the applications where high utilization factor and efficiency are required. Depending on application, power requirements change from kilowatts to megawatts. To investigate power limits of high-speed machines, the present feasibility study focuses on a 20 megawatt (MW) electric drive for marine propulsion. However, in addition alternative propulsion systems, ranging 100 kW to 20 MW, have been considered in an attempt to highlight some of the scaling rules that are apparent to high-speed machine considering their specific power level. In marine propulsion, the electric drive has to provide high torque at low speed to the propeller, however at different levels due to pole towing or open water operation. For electric drives, this tends to require high frequencies (large number of poles) as well as high currents. In general, ocean-going ships exist to provide affordable transport for cargo or passengers. In this respect, there exists a range of speeds within which virtually all ocean-going ships have operated and still operate. Within this range of speeds, roughly 10-30 knots, ship propulsion speed, in revolutions-per-minute (rpm), lie within a certain range, up to a couple of hundred rpm. The horsepower range coupled with propulsion rpm makes ship propulsion motor applications a high-torque, slow-speed electric drive. To deliver 20 MW propulsion power at a rotational speed of 150 rpm requires almost 1,300,000 newton meter (Nm) of torque. Emerging ship designs that employ different propulsion, e.g. water jets, may change this. However, in the following decades, ship propulsion motors will remain to be dominated by high torque, slow-speed motors, which are likely to remain for quite some time yet. In this respect, state-of-the-art ship propulsion motors are almost entirely alternating current (AC) synchronous wound field water cooled motors, or AC asynchronous induction motors. This report aims to give a general introduction to the concept of electrically-propelled vessels and presents specifically a feasibility study to a 20 MW high-speed permanent magnet synchronous motor (PMSM) to be used for ship propulsion. Although that also an initial attempt is documented to provide scaling laws for high-speed PM motor ranging from 100 kW to 20 MW. The purpose of this report constitutes a concept study and not an in-depth system analysis that would be required when implementing this technology for an electrical drive in future propulsion systems, such as ships or large vehicles. However, special attention is given to the apparent design challenges for these large high speed electric drives and their possible solutions

The high energy cosmic ray particle spectra measurements with the PAMELA calorimeter

Abstract Up until now there has been limited, contradictive data on the high energy range of the cosmic ray electron-positron, proton and helium spectra. Due to the limitations of the use of a magnetic spectrometer, over 8 years experimental data was processed using information from a sampling electro-magnetic calorimeter, a neutron detector and scintillator detectors. The use of these devices allowed us to successfully obtain the high energy cosmic ray particle spectra measurements. The results of this study clarify previous findings and greaten our understanding of the origin of cosmic rays

Modeling of permanent magnet synchronous machine with fractional slot windings

This paper focuses on simulation of permanent magnet synchronous machine (PMSM) with fractional-slot windings (FSW) in Modelica. Modeling of the electrical machines with object-oriented approach is shortly described, and a new Modelica library for simulation of electrical machines is introduced. The results of simulation of PMSMs with fractional slot windings are presented and explained. Special attention is paid to the higher harmonics and subharmonics produced by the winding and their influence on machine operation

Modeling of permanent magnet synchronous machine with fractional slot windings

This paper focuses on simulation of permanent magnet synchronous machine (PMSM) with fractional-slot windings (FSW) in Modelica. Modeling of the electrical machines with object-oriented approach is shortly described, and a new Modelica library for simulation of electrical machines is introduced. The results of simulation of PMSMs with fractional slot windings are presented and explained. Special attention is paid to the higher harmonics and subharmonics produced by the winding and their influence on machine operation

Harmonic wave model of a permanent magnet synchronous machine for modeling partial demagnetization under short circuit conditions

This paper proposes a multi domain physical model of permanent magnet synchronous machines, considering electrical, magnetic, thermal and mechanical effects. For each component of the model, the main wave as well as lower and higher harmonic wave components of the magnetic flux and the magnetic potential difference may be considered. The permanent magnets are modeled as discrete azimuthal segments in order to consider possible partial demagnetization effects. For each magnet segment a linearized temperature dependent B-H curve is considered. The main advantage of the presented model is that time transient operational behavior of a permanent magnet synchronous machine can be considered under various electrical, magnetic, thermal and mechanical conditions. The electromagnetic condition of surface magnet machine is compared with finite element analysis

PAMELA mission: heralding a new era in cosmic ray physics

After seven years of data taking in space, the experiment PAMELA is showing very interesting features in cosmic rays, namely in the fluxes of protons, helium, electrons, that might change our basic vision of the mechanisms of production, acceleration and propagation of cosmic rays in the galaxy. In addition, PAMELA measurements of cosmic antiproton and positron fluxes are setting strong constraints to the nature of Dark Matter. The continuous particle detection is allowing a constant monitoring of the solar activity and detailed study of the solar modulation for a long period, giving important improvements to the comprehension of the heliosphere mechanisms. PAMELA is also measuring the radiation environment around the Earth, and has recently discovered an antiproton radiation belt

PAMELA mission: heralding a new era in cosmic ray physics

After seven years of data taking in space, the experiment PAMELA is showing very interesting features in cosmic rays, namely in the fluxes of protons, helium, electrons, that might change our basic vision of the mechanisms of production, acceleration and propagation of cosmic rays in the galaxy. In addition, PAMELA measurements of cosmic antiproton and positron fluxes are setting strong constraints to the nature of Dark Matter. The continuous particle detection is allowing a constant monitoring of the solar activity and detailed study of the solar modulation for a long period, giving important improvements to the comprehension of the heliosphere mechanisms. PAMELA is also measuring the radiation environment around the Earth, and has recently discovered an antiproton radiation belt