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total harmonic distortion

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Advanced Member level 2
Oct 7, 2001
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I need some information about how to calculate THD on a 3 phase diode rectifier. How to choose L and C values of the filter? And related topics. So I need to learn 3 phase diode rectifier . Anybody can help me please?

several options

There are two ways to do the recitfication, half wave and full wave. Since diodes are cheper than inductors, I would suggest using the bridge.

half wave 18% ripple at 3 times the line frequency

full wave 4.2% ripple at 6 times the line frequency

The input filter inductor should be more than 35E-6 times the load resistance.

The shunt capacitor on the load side of the inductor is found by calculating the voltge divider effect at the ripple frequency of the L and C reactances. You need to first select a load ripple, divide it by the above ripples to get this factor.

Re: several options

Thanks but i need real formulas (not practical). How to calculate DC value of the rectified voltage. How to find rms value of the ripple voltage. How to find harmonic currents and how to calculate total harmonic distortion. How does changing L and C values affect the input currents etc. Are there any source or anybody which or who can clear my mind? I will be very grateful.

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