Browsing by Author "Statt, Cundell"
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- ItemA comprehensive simulation based methodology for optimal design of a PMSM drive(Stellenbosch : Stellenbosch University, 2021-03) Statt, Cundell; Strauss, Johann M.; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.ENGLISH ABSTRACT: One of the biggest problems with regards to electric vehicles is range and charge times.Therefore, the efficiency of the electric drive train is of utmost importance. This has resultedin the common use of three-phase brushless permanent magnet synchronous machines. Dueto the DC nature of batteries, a three-phase motor drive is needed, which is the focal pointin this thesis. Although efficiency is one of the key design focuses, a compromise has to be made betweenthis, cost and weight. A compromise is never an easy task to perform however, the moreinformation available, the more accurate of a choice can be made. Thus, a method usingsimulation was developed aiding in the process of setting the minimum MOSFET specifica-tions. From this, the losses of each MOSFET in the selection can be determined through asecond Simulink simulation. Typically the choice of switching component would now be made with the thermal effectsbeing a secondary design process. However, placing the thermal aspect at the forefront ofthe design can result in a large savings in cost and weight, due to a reduction of coolingrequirements. For this reason, a method using computational thermodynamics was developedto allow multiple design revisions to be tested and optimised.To further aid in the choice of the optimal MOSFET, each MOSFET in the selection issimulated in the thermal model using the previously determined losses. The maximumtemperature for each MOSFET is determined, clearly indicating which MOSFETs are thethermally optimal choice.The design and construction of a5kWpermanent magnet synchronous machine drive iscompleted. From this, the accuracy of the simulations can be tested and confirmed. The driveis focused on lightweight vehicle applications such as the vehicle produced by the companyMellowcabs. Thus, simulations were run focusing on the optimisation and improvement oftheir cooling method to reduce cost and weight. By doing this the benefits of placing thethermal aspect at the forefront of the design can clearly be seen.