Open Circuit

Figure 4.45 shows the open circuit emf results predicted by the FEA plotted on the same axis as the experimentally measured results. The correlation between the two is good, although the model can over predict by up to 15 % (e.g. at time « 0.8) the RMS value is within 10%. As, by definition, no current flows in an open circuit test, the predicted results were obtained simply by differentiating the predicted flux linkage time profile from the experimental time displacement results. Confidence can hence be placed in the FEA flux predictions, and their subsequent use in the proposed performance models.

Figure 4.45 shows the open circuit emf results predicted by the FEA plotted on the same axis as the experimentally measured results. The correlation between the two is good, although the model can over predict by up to 15 % (e.g. at time « 0.8) the RMS value is within 10%. As, by definition, no current flows in an open circuit test, the predicted results were obtained simply by differentiating the predicted flux linkage time profile from the experimental time displacement results. Confidence can hence be placed in the FEA flux predictions, and their subsequent use in the proposed performance models.

Figure 4.45: Open Circuit emf

The predicted waveform is more regular and slightly larger than the experimental results. It is likely that three dimensional end effects, not considered in the FEA, are responsible for this. Simulated results also appear to move slightly out of phase during the time period shown. The model was run with the exact analogue displacement data obtained from the transducer. Superimposed on this signal was a high frequency noise signal, produced unavoidably from the inverter used to drive the test rig. As the displacement signal has to be differentiated into velocity, this noise becomes significant and hence requires filtering. A 200 point moving average method was used, and it is likely that this will account for the gradual loss of agreement between predicted and actual displacement results. Alternatively, a calibration error in the displacement transducer would account for the affect.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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