Question

Need help with e) and f).

e) Derive a formula and give the numerical value for the input power factor of Phase A.

f) Derive a formula and give the numerical value for the THD of the line current ia(t)

Q3: Three-phase rectifier with six diodes [15pts] The three-phase diode-rectifier below has six diodes and a purely resistive load Rout. The sinusoidal input voltage sources (with a phase difference of 120') are star-connected and have the line-to- neutral amplitude Vn and the angular frequency w. Assume the system to be balanced and all diodes to be ideal. Load vo an bn a) Draw the line-to-neutral voltages van(t), vbn (t) and ven (t) for (at least) one full period. Clearly mark in your plot when each diode is conducting and explain how you determined when the diodes are conducting and when they are blocking. [2pt) b) Draw the waveforms for vo (t) in your previous plot (or in a new plot) and derive a formula for the average output voltage Voavg. [2pt c) How are the average output power and the average output current related to the output voltage? [1pts] d) Derive a formula and give the numerical value for the ripple factor of the output voltage. 12pts] e) Derive a formula and give the numerical value for the input power factor of phase A. [4pts f) Derive a formula and give the numerical value for the THD of the line current ia(t). [3pts) E) Would the average output voltage be smaller, larger or the same if we include source inductances La. L and L? Explain why. [1pts)

Answer 1

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