Page - 316 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2016,9, 10 ȱ Figure9.q-Zsourcebasedvoltageboostcontrol sequences. The transmitter and receiver inFigure 6 arehighorder resonantfilters,whichonly allow the power signals at resonant frequency to pass through. Thuswe should evaluate the fundamental components of thewavesproducedby theHBridge. TheFFT series of squarewavesdepicted in Figure10 isgivenas: V“ 8ÿ n“1,2.3... 2A nπ „ cos nπTnon´ef fective T ´cosnπp1´Tnon´ef fecitve T q j sinnωrt (18) where A, n, Tnon´ef fective and T represent the amplitude of the square wave, harmonic order, non-effective time and cycle time, respectively, and ωr = 2π/T is the system angular frequency. AccordingtoEquation(15),A isactuallydeterminedbyBF, andTnon´ef fective isdeterminedbyTdead, Tshifting andTshoot´through. Thus theoutputvoltageproducedby theHBridge canbe regulatedby controllingtheseparametersappropriately,whereas thevoltagestressacross thepowerswitchesneeds tobeconsideredbeforedesigningtheBFparameter. ThedegreeofapproximationbetweenthesquarewaveshowninFigure10andaquasi-sinusoidal wavecanbequantifiedbyTHD,andthe lower theTHD, the less theharmonic loss. TheTHDof the squarewaveconsistedofdifferentnon-effective timescanbecalculatedaccordingtoEquation(19), whereVn represents thedifferentharmonicamplitudes: THD“ d 8ř n“2,3,4... V2n V1 (19) ȱ Figure10.Typical squarewaveproducedbytheHBridge. 316