Magnetically geared induction machines

A wound-rotor induction machine is artfully coupled to a magnetic gear to achieve a high-torque-density drive system called magnetically geared induction machine (MaGIM). The high-speed rotor of MaGIM is common to both the machine and gear sides. A rotating diode rectifier electrically links the machine's wound rotor and a dc boost winding on the gear side to increase the torque-transmission capabilities of the overall system. The first investigations on a 100 kW-120 r/min MaGIM are promising, since an increase in torque of ∼ 15% could be obtained by inserting the diode rectifier. For fixed speed applications, this induction-machine-based system can be directly supplied from the main

3D thermal analysis of a permanent magnet motor with cooling fans

Overheating of permanent magnet (PM) machines has become a major technical challenge as it gives rise to magnet demagnetization, degradation of insulation materials, and loss of motor efficiency. This paper proposes a state-of-the-art cooling system for an axial flux permanent magnet (AFPM) machine with the focus on its structural optimization. A computational fluid dynamics (CFD) simulation with thermal consideration has been shown to be an efficient approach in the literature and is thus employed in this work. Meanwhile, a simplified numerical approach to the AFPM machine with complex configuration in 3D consisting of conduction, forced convection, and conjugate heat transfer is taken as a case study. Different simplification methods (including configuration and working conditions) and two optimized fans for forced convection cooling are designed and installed on the AFPM machine and compared to a natural convection cooling system. The results show that the proposed approach is effective for analyzing the thermal performance of a complex AFPM machine and strikes a balance between reasonable simplification, accuracy, and computational resource

Model predictive direct torque control and fuzzy logic energy management for multi power source electric vehicles

This paper proposes a novel Fuzzy-MPDTC control applied to a fuel cell battery electric vehicle whose traction is ensured using a permanent magnet synchronous motor (PMSM). On the traction side, model predictive direct torque control (MPDTC) is used to control PMSM torque, and guarantee minimum torque and current ripples while ensuring satisfactory speed tracking. On the sources side, an energy management strategy (EMS) based on fuzzy logic is proposed, it aims to distribute power over energy sources rationally and satisfy the load power demand. To assess these techniques, a driving cycle under different operating modes, namely cruising, acceleration, idling and regenerative braking is proposed. Real-time simulation is developed using the RT LAB platform and the obtained results match those obtained in numerical simulation using MATLAB/Simulink. The results show a good performance of the whole system, where the proposed MPDTC minimized the torque and flux ripples with 54.54% and 77%, respectively, compared to the conventional DTC and reduced the THD of the PMSM current with 53.37%. Furthermore, the proposed EMS based on fuzzy logic shows good performance and keeps the battery SOC within safe limits under the proposed speed profile and international NYCC driving cycle. These aforementioned results confirm the robustness and effectiveness of the proposed control techniques.Web of Science2215art. no. 566

Review of magnetic gear technologies and their applications in marine energy

The marine energy industry is in its early stages but has a large potential for growth. One of the most significant challenges is the reduction of operation and maintenance costs. Magnetic gears (MGs) offer the potential for long periods between maintenance intervals due to their frictionless torque transmission which could reduce these costs. This study presents a summary of the state of the art in MG technology and then investigates its potential for marine energy applications. A brief overview is given of the state of the marine energy industry and the environment in which marine energy converters (MECs) operate. A short history of MG development over the past century is then presented followed by a discussion of the leading MG technologies and their relative advantages. In order to demonstrate the potential of MGs in marine applications, the current technologies, i.e. mechanically geared and direct drive machines, are examined in terms of sizing, reliability and economic value using previous studies on a similar technology, namely wind. MGs are applied to four types of MECs to demonstrate how the technology can be incorporated. The potential to deploy at scale and potential obstacles to this are then discussed

Eddy current in a rotating cylinder in a static field by a stochastic method

This paper deals with the calculation of eddy current in a copper cylinder. This cylinder rotates in an applied static magnetic field. The electromagnetic problem is solved in two-dimension by considering transient motion. Two methods for eddy current computation are compared: stochastic method and classical finite element method. The main goal of this paper is to compare these methods

Scaling solution and n dependance of the eddy current distribution in a flat superconductor

International audienceIn this paper we propose an approximate analytical solution of the problem of nonlinear diffusion of the current density in a HTS superconducting plate with current transport. It is obtained by the technique of the self-similar solution. The construction of this solution highlights a characteristic time of penetration Tp whose limit for large n is the model of Bean. We compare our solution to the ones obtained using COMSOL multiphysics. We study the influence of variation of the magnetic induction on the time penetration and the influence of the n factor on the time penetration