This thesis proposed an analytic modelling of electric machine losses for the generation of efficiency maps and a simplified version model for optimization purposes. The validation of the models showed that they can be utilised for fuel efficiency optimization in a parallel HEV as long as the electric machines are operated at low rotational speed and at low to middle torques. At high rotational speed and at very low torques, the difference between measured and simulated efficiencies may be reduced by a deeper investigation in iron loss models for both Asynchronous Machine (ASM) and Permanent-magnet Synchronous Machine (PSM). In contrast, simulated efficiencies at low and middle speed (near the rated point) showed good agreement with the measured efficiencies. Additionally the accuracy of the calculation of the leakage inductances was found to be unsatisfactory, although its influence on the electric machine efficiency (EM) was negligible. The advantages of describing driving strategy and electric machine losses analytically were detailed while defining the optimization target. Through a linearization of the EM losses, the losses of the internal combustion engine (ICE) and the EM were described homogenously. By using a non-linear approach in the loss description, the effects of the EM losses on the fuel-efficiency-optimizing driving strategy were further detailed. For instance, without the need of running vehicle simulations, the optimal ZEV mode strategy could be calculated depending on the EM type, as well as the influence of changes in the machine design on the driving strategy. For standard PSMs, the ZEV-border was 35 Nm at 1500 1/min, equivalent to 270 g/kWh in a ICE consumption map, whereas for the ASM the value was 15 Nm at 2000 1/min, equivalent to 330 g/kWh in the ICE consumption map.
Electric drive design for hybrid electric vehicle optimum fuel efficiency
Entwurf eines elektrischen Antriebs für ein hybridelektrisches Fahrzeug mit optimaler Brennstoffausnutzung
Berichte aus der Fahrzeugtechnik ; 1-239
2008
239 Seiten, Bilder, Tabellen, Quellen
Theses
English
Automotive engineering | 1993
|Online Contents | 1993
Optimum Battery Size for Fuel Cell Hybrid Electric Vehicle- Part I
Online Contents | 2007
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