Juho Montonen

Design Principles of Permanent Magnet Synchronous Machines for Parallel Hybrid or Traction Applications

Hybrid and full electric technologies are fast emerging in vehicles and mobile working machines, where electric machines and internal combustion engines are used together to power the systems. Permanent magnet (PM) technology plays an important role here despite the high magnet prices. This paper theoretically and empirically studies the design principles of PM synchronous machines (PMSMs) for hybrid applications, where a high starting torque and a wide field weakening range are needed. Several embedded-magnet PMSM magnetic circuit topologies are considered as possible candidates. A 10-kW PMSM prototype was built and tested. Experimental results verify the theoretical considerations well.

Design of a Traction Motor With Tooth-Coil Windings and Embedded Magnets

Traction motor design significantly differs from industrial machine design. The starting point is the load cycle instead of the steady-state rated operation point. The speed of the motor varies from zero to very high speeds. At low speeds, heavy overloading is used for starting, and the field-weakening region also plays an important role. Finding a suitable field-weakening point is one of the important design targets. At the lowest speeds, a high torque output is desired, and all current reserves of the supplying converter unit are used to achieve the torque. In this paper, a 110-kW 2.5-p.u. starting torque and a maximum 2.5-p.u. speed permanent-magnet traction motor will be studied. The field-weakening point is altered by varying the number of winding turns of machine. One design is selected for prototyping. Theoretical results are verified by measurements.

Design of a traction motor with two-step gearbox for high-torque applications

New combination of an electrical machine and a two-step planetary gear for high torque traction applications is introduced. This kind of a machine can act as a propulsion motor for working machines such as e. q. agricultural tractor that needs to generate very high traction forces and also higher travelling speeds. The technology also suits in some road vehicle use e.g. for buses or trucks. Detailed information about the electrical machine design is provided. The machine has tooth-coils in the stator, embedded permanent magnets in the rotor and its cooling is arranged via the gear lubrication as the chamber is semi-filled with oil.

Integrated hub-motor drive train for off-road vehicles

A new concept that integrates a permanent magnet (PM) synchronous motor (PMSM) and a 2-step planetary gearbox for heavy machinery electric traction is introduced. A clear need for this kind of a solution is recognized in the field of diesel-electric hybrid off-road vehicles as electrical machine cannot fulfill alone all the demands of the typical load cycles of working machines. The technology introduced also suits in some road vehicle use e.g. for buses or trucks. The benefits of the solution are pointed out and its functionality is proven by simulations. The dynamic performance of the driveline is analyzed using a co-simulation approach that accounts the mechanical system and the dynamics of the control system.

Energy efficiency of hoisting motors

This study concentrates on energy efficiency of hoisting motors in industrial cranes. Motors in the scope are of three-phase cage-induction type and specially designed for intermittent duty S3. The main focus is on converter-fed motors. For a motor of certain rated power dimensions and rotor material are varied and electrical efficiency as a function of load is calculated. Energy consumptions for typical load spectra and operating hours are determined and compared to the energy consumptions of material production. It is shown that for light loads and infrequent usage manufacturing phase constitutes a significant part of the total energy consumption. Thus, increasing the efficiency of a motor may not provide notable energy savings. However, at high loads and operating hours better efficiency decreases the life-cycle energy consumption of an intermittent duty motor as well.

Comparison of electric motor types for realising an energy efficient pumping system

Energy efficiency in pumping is partially affected by the electric motor efficiency. In addition to low losses, the chosen electric motor type should have feasible reliability and dimensions for pumping systems. This paper studies the applicability of common electric motor types to a future pumping system by comparing motor characteristics with each other; both a qualitative and quantitative evaluation is performed for a 15 kW induction, synchronous reluctance and permanent magnet synchronous motor. Another main object of this paper is to provide basic information for designing a next generation, more energy efficient pumping system.

Impact of semi-magnetic slot key on the performance of a tooth-coil traction motor

Fractional-slot non-overlapping-winding permanent magnet synchronous machine for traction application is designed. Detailed comparison of the performance of electrical machine is provided with and without semi-magnetic slot wedges. Usage of slot wedges brings some efficiency benefits while partially eliminating permanent magnet losses. It however, increases the synchronous inductance which results in lower peak torque but a higher field weakening area.

Application of Hub-Wheel Electric Motor Integrated With Two Step Planetary Transmission for Heavy Off-Road Vehicles

An integrated electro-mechanical drive train component for heavy duty vehicles in off-road applications is presented. The component utilizes a two-step transmission and a tooth-coil permanent magnet motor and has compact size enabling in-wheel installation. The driveline design procedure is surveyed to explore the advantages of a geared electric motor in electric drivelines. Multibody dynamic simulation is applied to verify the functionality of the driveline. A vehicle generic model that is compatible with a multibody simulator program is developed to describe the performance of the proposed driveline in different vehicles. A co-simulation procedure is applied to combine the electric motor and vehicle body simulation models. It is shown that the co-simulation can be performed in real-time, thus enabling a human driver to control the vehicle. A comparison is made of the rear wheel drive and wheel mounted electric motor from the efficiency and performance points of view. The power consumption of vehicles with different driveline architectures is calculated to diagnose the weak points of the system and enhancement solutions are proposed.Copyright

Design process of a traction motor for a hybrid bus application

This study addresses the requirements of a traction motor design process. In a traction application, the design parameters are electrical, mechanical, and thermal issues, and especially, the reliability. The electrical design optimizing process of a motor takes into account the magnet shape, the magnet embedding depth, and the flux-guiding air pocket areas on the magnet sides. The application in question is a hybrid bus with a permanent magnet motor, a diesel prime mover, and a generator as a series drive system. In a traction application, the efficiency should be sufficient over a wide speed range, despite the fact that the torque demand can be very challenging.