Optimization of motor and gearbox for an ultra light electric vehicle

The integrated design of the drivetrain of a single person ultra light electric vehicle powered by batteries is optimized towards high efficiency and low mass. The drivetrain of each front wheel consists of an outer rotor permanent magnet synchronous motor (PMSM), a gearbox and the power electronics with converter and control print. The complete drivetrain is optimized for the New European Driving Cycle and the Federal Test Procedure. For the optimization of the complete drivetrain analytical models are used to calculate the losses and the efficiency. The analytical models are fast, and useful for designing a good PMSM in combination with a gearbox. The optimization of the drivetrain over the driving cycles makes it possible to choose the optimal combination of motor and gearbox for different gear ratios in order to have high efficiency and low weight. Comparing a single-stage gearbox with a twostage gearbox, a single-stage gearbox has a higher efficiency, but also a higher weight than a two-stage gearbox with the same properties. The optimization of the dynamic behavior of the drivetrain over the driving cycles yields a compromise between the total efficiency and the total mass of the drivetrain. The optimum choice will depend on the intended use of the vehicle (drive cycle)

Optimal design and implementation of a drivetrain for an ultra-light electric vehicle

This paper presents an integrated design of a drivetrain for a single-person ultra-light electric vehicle (ULEV). To calculate losses and efficiency of the inverter, the permanent magnet synchronous machines (PMSMs) and the gearbox, parameterised analytical models are used. For the gearbox - which has a single gear ratio - the studied parameters are the gear ratio, the number of stages, the number of teeth and the module of each spur gear combination. The novelty of the paper is that it learns how the total average efficiency and the total mass of the drivetrain depend on the gear ratio, on the number of stages in the gearbox, on the motor parameters and on the chosen several driving cycles including the new European driving cycle (NEDC). On the basis of the presented results, it is possible to choose the right configuration of power electronics, PMSM and gearbox in order to have a good trade-off between high efficiency and low mass

Ultra light electric vehicle with high efficiency

The complete drive train (gearbox + motor + power electronics) of an ultra light electric vehicle is optimized towards minimal total weight and maximal efficiency for the New European Driving Cycle

Influence of soft magnetic material in a permanent magnet synchronous machine with a commercial induction machine stator

This paper presents the efficiency study of a 6-pole and 2-pole induction motor (IM), converted into a 6-pole and 2-pole permanent magnet synchronous machine (PMSM). Firstly, the stator of the IM was kept unchanged and the rotor was converted into a permanent magnet (NdFeB magnets) rotor, resulting in higher average efficiency. Secondly, we investigated how much the efficiency can be increased by replacing the electrical steel in the stator by another material grade. The numerical approach is based on the finite element method (FEM), taking into account the rotor movement. Iron losses are computed according to the loss separation theory. From measurements and simulations, it is observed that the efficiency increases significantly compared to the original IM. The average efficiency of the original 1.5 kW IM converted into the 1.5 kW PMSM led to a 14% higher efficiency in a speed range 0.5 Omega(nom) - Omega(nom) and torque range 0.5T(nom) - T-nom. When the stator iron is replaced by M235-35A laminations with the same geometry, the average efficiency increases by an additional 2% for the 1.5 kW PMSM with modified stator

Towards low energy mobility using light and ultralight electric vehicles

Electrical vehicles are seriously considered today. However their energy needs depend seriously on the way how they are designed, ranging from electric bicycles to the electrical utility vehicle, it can differ from 1kWh to more than 20kWh/100km. One can look at the problem if it is better to use compressed natural gas in a vehicle directly or is it better to make electricity first and use that electricity in an electric vehicle. A special attention is given to the development of ultra-light electric cars “Ecologic Low Budget Electric Vehicle” ELBEV. It permits to cut down the energy consumption down to 2-3kWh/100km, especially suited for single person daily commuting needs.Les véhicules électriques sont pris au sérieux dans les temps actuels. Cependant, leur consommation dépend très fort comment ils sont conçus, du vélo électrique, au véhicule utilitaire, cela peut changer de 1kWh vers plus de 20kWh/100km . On peut aussi entrevoir si on fait mieux de rouler avec du gaz comprimé ou de produire de l'électricité et de l'utiliser dans un véhicule électrique. Une attention spéciale est donne au développement des véhicules ultralégers "Véhicule électrique écologique à budget limité" VEEBL. Cela permet de réduire la consommation vers des valeurs très basses de 2-3kWh/100km, spécifiquement utile pour les déplacements quotidiens

Optimization of the rotor geometry of a permanent magnet synchronous machine

Converting an induction machine (IM) to a permanent magnet synchronous motor (PMSM) can be a solution to increase the efficiency. Therefore we started from an original 1.5 kW 6-pole IM and converted it into a 6-pole PMSM. The stator of the 6-pole IM was kept unchanged and the rotor was converted into a permanent NdFeB magnet rotor. Furthermore we want to optimize the rotor geometry to obtain high efficiency and low magnet volume to reduce the magnet cost. In addition the cogging torque should be low, and the mechanical power should be at least equal to the nominal power of the induction machine at nominal current. The optimized parameters are the magnet thickness (tm), the number of magnet segments per pole (Np) and the magnet pole angle ("alpha" m). For simulating the 6-pole PMSM’s a transient 2D finite element model (FEM) was used, taking into account iron and copper losses. A geometry (Np = 5, "alpha"m = 150°, tm = 3 mm) was found so that the PMSM has 82.7% average efficiency and nevertheless rather low cogging torque (0.51 Nm) and magnet volume (11.1 cm³)