3-Phase Inverter RMS power computation

[JAVIER-MOTA]

Hi everybody, 

I've been calculating the power efficiency of a three phase inverter in different ways and I have a doubt regarding which way is the correct one. I obtained the following results:

3 * rms(P(R1)) / rms(P(V1)) = 120%

3 * (rms(I(R1)*I(R1))  * R1)  / rms(P(V1)) = 120%

3 * (rms(I(R1)) * rms(I(R1)) * R1)  / rms(P(V1)) = 80%

From previous results, I am a little bit confused since formulas 1 and 2 seem to be correct but they give an inconsistent efficiency value .

I hope you can clarify this for me,

Best regards,