Student: I can't figure out how to do that, since I can't seem to cut off more than two of the four corners. Mentor: Don't worry, what I asked you to do is actually impossible! There are only six faces on a cube, so the highest number of sides possible is six. Student: That makes sense. I bet you can do that with any prism-it's just a matter of angling the cross section correctly to intersect all of the faces. Mentor: You're very right, any prism can be cut in such a way that the cross section has as many sides as the prism has faces. However, not all shapes have this same property.
Recently, a new technology i.e. variable frequency transformer (VFT) has emerged as a flexible ac link to transfer power in-between asynchronous power grids. Hence, this paper aims to explore the possibility of grid integration of PMSG based WTG using VFT.
If, however, an application or production process requires an adjustable AC voltage (that is, a controllable speed), frequency inverters are used. These frequency inverters can generate an AC voltage that is variable in amplitude (the output voltage level) and frequency from a constant AC voltage. How does a frequency inverter work? A frequency inverter is therefore connected upstream of a motor to generate an AC voltage that can be adjusted to meet customer requirements.