Question

1. a.Let Vr = 10 sin(100πt), Vy= 10 sin(100πt – 2π/3) and Vb = 10 sin(100πt + 2π/3) be the voltages in stationary reference frame RYB that have the r-axis, y-axis and b-axis displaced spatially from each other by 120 deg apart. These three voltages are transformed into a dq rotating frame which is rotating at a frequency of 20Hz wherein the q-axis is aligned along the voltage space vector. Then, what is the value of frequency of the signal in the d-q axes frame.                                                        b.The output of an inverter is connected to grid via 1:1 transformer. The equivalent circuit of transformer has a leakage reactance of 1 mH at both primary and secondary side. The magnetizing reactance of the transformer is 100 mH. Then, what will be the impedance seen between the inverter and grid?

Answer 1

a leiven a balanced reoltage soux RYB. confgaration as * Vr Refence plane Stationaly. No NR = losin (100 t). Vyclosin (100 xt - 120) VR = losin (1oo5t +120 • 100a If = 5042 » g fare Now, all the three voltages are transformed into dq rotating fame which is rotating at freq = 2012 fdg using concept of Relatine - factures o fret in do frame felt by Voltage source - - fuet factual - Food pame. & fret = 50-20 = 3042. Vale of feg in dq-frame = 2012. o

having Griven, a lil transformer is connected blue an invertor & grid. leakage impedence indictance. A Li primary sidee) = ₂ (secondary side) = 'my. magnetizing reactance the tm = 100mm, So, netwosk is as. om + Inverte Grid Heerlee no using AB CD parametu concepte ®- = [46] [67] mo Now transfering primary sides La from gives. secondary to

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