ANALYTICAL DYNAMIC THERMAL MODEL FOR SQUIRREL CAGE MOTORS USING SYSTEMMODELER
Söderäng, Emma (2016)
Kuvaus
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Tiivistelmä
Importance of accurately predicting the thermal behavior of electric motors is of growing interest. This is due to the fact that careful design of a motor in terms of thermal behavior may significantly improve the overall performance of a motor. In addition, the temperature is the main limiting factor for motor loading.
This thesis focuses on transient thermal behavior for three phase squirrel cage motors of intermittent duty types. Motors of these duty types may operate below and above rated torque and hence their dynamic thermal model is different from a steady-state thermal model. In a dynamic thermal model heat is stored in the different parts of the motor while the stored heat can be neglected for stationary thermal modelling, where it is enough only to simulate for thermal equilibrium.
SystemModeler offers an opportunity to develop different tools for various types of calculations, but in this thesis the focus is on thermal analysis. The purpose of this thesis is to investigate how SystemModeler could be used when developing thermal models for squirrel cage motors of intermittent duty types. The target is to develop an analytical thermal model which is easy to use while being sufficiently accurate. The needed motor parameters should also be easily available. The basic information about the motor and information about operational as well as standstill time are filled into the tool. The main challenge with thermal models is the fact that many thermal phenomena are practically impossible to calculate and different correlations are needed.
With help of the tool it is possible to predict how a motor of intermittent duty type would be heated during operation. Since all motor types had test results for thermal equilibrium it was possible to calibrate the thermal model for steady state before simulating transient conditions. The main advantages with tools developed in SystemModeler are that the structures of the created codes are readily accessible and easily modifiable. In addition the created model can be run over the network as an independent tool.
This thesis focuses on transient thermal behavior for three phase squirrel cage motors of intermittent duty types. Motors of these duty types may operate below and above rated torque and hence their dynamic thermal model is different from a steady-state thermal model. In a dynamic thermal model heat is stored in the different parts of the motor while the stored heat can be neglected for stationary thermal modelling, where it is enough only to simulate for thermal equilibrium.
SystemModeler offers an opportunity to develop different tools for various types of calculations, but in this thesis the focus is on thermal analysis. The purpose of this thesis is to investigate how SystemModeler could be used when developing thermal models for squirrel cage motors of intermittent duty types. The target is to develop an analytical thermal model which is easy to use while being sufficiently accurate. The needed motor parameters should also be easily available. The basic information about the motor and information about operational as well as standstill time are filled into the tool. The main challenge with thermal models is the fact that many thermal phenomena are practically impossible to calculate and different correlations are needed.
With help of the tool it is possible to predict how a motor of intermittent duty type would be heated during operation. Since all motor types had test results for thermal equilibrium it was possible to calibrate the thermal model for steady state before simulating transient conditions. The main advantages with tools developed in SystemModeler are that the structures of the created codes are readily accessible and easily modifiable. In addition the created model can be run over the network as an independent tool.