Do you know how can I measure the AC-AC power transfer efficiency of this system?
Method 1:
Using a
Wattmeter you can measure active power. Use the wattmeter to measure the input and the output power (if output is DC or the load is resistance, you would not need this one to calculate the output power). Ask in your university about this one. It is very likely to have (at least) one.
Mehtod 2:
1)Measure the RMS voltage at the input using an oscilloscope or a multimeter which has the label "True RMS".
2)Measure the RMS current at the input using an oscilloscope or a multimeter which has the label "True RMS".
3)Measure the phase difference between the input voltage and the input current.
4) Active Input Power = 1) * 2) * cos(3))
5) Do the same thing in order to get the Active Output Power unless the load is resistive. Besides, if DC at output, simply VDC^2/Rload. If output is AC, VRMS^2/Rload.
Last step: Power Transfer efficiency (eta) = Pout/Pin
...but I am not sure how to measure and calculate it.
In order to calculate it, you can do the same as above but mathematically.
Probably it is easier to compute the Pin as Pin=Pout + Power lost in resistive elements along the circuit
Power lost in a resistance is simply found as : P=IRMS^2 * R = VRMS^2/R = VRMS*IRMS