What is a Magnetic Geared PM Synchronous Machine?
Magnetic geared electric machines are relatively new technology. Their concept is based on the integration of a magnetic gear inside an electric machine. This combination includes an electromechanical power conversion system, which is an electric motor or generator, and power transmission system, which is the magnetic gear device. Issues coming from the use of traditional gearboxes like friction, noise, vibration, heat loss and overload risk can be minimized using the integrated magnetic gear. Combining both the magnetic gear and the electric machine helps to improve the overall system efficiency and power density. The resulting system has a compact and lightweight structure with reduced lubrification and maintenance costs. It constitutes a great solution for e-mobility applications and electricity production.
PM synchronous machine
Magnetic geared Motor [1]
Conventional driving system vs MG-PMSM based driving system used for tram [1]
Design Challenges of a Magnetic Geared PMSM
In addition to the typical design challenges of electric machines, this electromagnetic device poses extra issues related to the magnetic gear system. Both systems might be studied separately and/or combined. Below are few of the design challenges that may encountered while designing a geared PM synchronous motor:
- Geometry creation and modification (2D and 3D)
- Winding configuration and simulation setup
- Study the magnetic gear system: torque and speed calculations, reducing torque ripples, investigating different permanent magnet types, etc.
- Study the machine under no load and on load conditions: cogging torque, back emf, short circuit response, load torque, voltage, current, etc.…
- Static and dynamic winding parameters computation (R, L, etc.)
- Electromagnetic losses calculation
- Motion coupling and system drive
- Transient and steady state temperature evaluation
EMWorks Solution for Electric Machines
EMWorks proposes a complete solution to tackle different design challenges posed by electric machine in general. This solution comes with three tools integrated inside the same platform. To overcome issues related to easy and complex geometry creation and editing, this solution is embedded inside SW and Autodesk Inventor which are powerful, flexible, and user-friendly CAD tools.
This package includes both 2D and 3D electromagnetic simulations, EMWorks2D and EMS, with Multiphysics analysis capabilities. Thermal, motion, linear static and circuit simulator can be coupled with magnetic analysis to capture different aspects of your machine. In addition to this, EMWorks solution comes with a with template-based motor CAD design and simulation software. Users generate automatically their electric machines based on a wide range of templates available in the software. You need to define your machine properties including geometrical parameters, machine settings (rated power, speed, excitations, winding configurations) and simulation required outputs, then the software will take care of the rest. The software also gives you several options of analyses including a quick and accurate semi analytical solution to get plenty of results like efficiency map, power vs speed etc; no load analysis, DQ model calculation, on load analysis, etc.
Results generated using EMWorks2D and EMS
EMWorks solution provides all needed results that help designers to study, size and optimize their magnetic geared PM machine. The following are few, but not all, EMS and EMWorks2D results; back emf, cogging torque, load torque, currents, mechanical parameters (displacement, speed and acceleration), steady state and transient temperature, thermal and mechanical stresses, etc. EMS allows coupling to different motion directions to better understand the working principles and operation of a magnetic geared motor. More sophisticated motion options like multi directions force and torque capability, a combined rotary and linear motion analysis within a same setup i.e in case you have a translating and rotating component (electrodynamic wheel) can be used with EMS motion coupling. Furthermore, several advanced features such as spring, damper, gravity, predefined movements, initial velocity, and touching case motion, etc, are handled by this motion coupled analysis. All together makes EMWorks solution a truly motor design and simulation tool.
Below are some results generated by EMS 3D and EMWorks2D software.
Magnetic flux results of the magnetic gear system: a) 3D fringe plot, b) animation vs outer and inner rotor position, c) airgap flux vs different PMs
(a)
(b)
(c)
Torque results of the magnetic gear: a) one rotor is moving, b) both rotors are moving, c) torque vs PMs
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(b)
Magnetic flux results of the magnetic geared PM synchronous motor: a) fringe plot of the flux at static position, b) fringe plot of the flux when both rotors are rotating in different directions
Back emf results at no load short circuit current of the motor
Magnetic Geared PM Synchronous Machines (MG-PMSMs) blend the robustness of magnetic gears with the efficiency of PM motors, promising transformative advances in e-mobility and energy generation. Despite design complexities, such as intricate geometry and multi-physics analysis, EMWorks solutions offer comprehensive tools to overcome these hurdles, paving the way for compact, efficient, and reliable MG-PMSMs that meet the growing demands of modern industrial and transportation applications.