What is a single phase PWM inverter

Single-phase U-inverter full bridge with sine PWM simulation

I am currently working on a simulation of a single-phase voltage inverter full bridge with sine PWM in the PSIM program from university.
I have already created the attempt at synchronized rigging and the resulting control curve.
However, the second attempt I have problems. The task is:

... with practically designed inverters, switching frequencies are selected that are above the human hearing threshold, e.g.
fs> 16 kHz. With these high switching frequencies, there is no requirement to maintain synchronous clocking.
Now set the control voltage ust so that a power of P = 3 kW with a cos 􏰀 = 1 is fed into the network. Enter the associated initial value of the current through the inductance L. Now run simulation runs for the switching frequencies
fs = 1 kHz / 10 kHz / 20 kHz through. Set the simulation time to 20 ms in each case. Then carry out an FFT of the output voltage uab and the load current iL.

I'm relatively at a loss ... I neither know how exactly I should determine the performance in my circuit (not even with Hab or Ue ...), nor do I know exactly what the task is meant ... Should I do it Change inductance or not? Do I not have 2 unknowns (voltage and current) when determining the power?
I hope someone can tell me how I can determine the power that is fed into the grid in such a circuit.
Thanks in advance!