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.
A variable-frequency drive (VFD) (also termed adjustable-frequency drive, variable-speed drive, AC drive, micro drive or inverter drive) is a type of adjustable-speed drive used in electro-mechanical drive systems to control AC motor speed and torque by varying motor input frequency and voltage.n the United States, an estimated 60-65% of electrical energy is used to supply motors, 75% of which are variable-torque fan, pump, and compressor loads. Eighteen percent of the energy used in the 40 million motors in the U.S. could be saved by efficient energy improvement technologies such as VFDs.