Hi. I am writing a report on an experiment. The experiment is on power electronics. An investigation of V /f constant control of induction motor with inverter was carried out. A converter and an inverter are connected to an induction motor to change AC to DC and back to AC, as shown in the diagram. . The output frequency of the inverter is set to 20, 30, 40, 50, 60, 70 Hz and the output voltage, output current and rotation speed (rpm) of the inverter are then recorded. I want to know the reason to the results for f-V relation. At first they're proportional but when it reaches 225 V, the voltage seems to go constant, why is that? My teacher said this was expected to happen and we have to write out the reason. Help, please?