How to measure the current strength if the control is via PWM?

Question

Arduino

Good afternoon.
There is a Chinese CO2 laser engraver with a 30W tube, it is controlled by PWM, constant voltage, the input is about 15kV.
I need to figure out the current strength roughly speaking. If you use an analog milliammeter (yes, the maximum can be 30mA), then, of course, everything is fine.
But I need to connect to Arduino, for this I use INA219 but the problem is that the readings "float" due to PWM. Frequency 20-25kHz.
Tell me, please, how can I solve the problem?
PS The multimeter with TRUERMS seems to be measuring correctly, but I have an Arduino and I can't find an algorithm for how to filter the value and I don't know if the Arduino will have time to calculate.

Answer 1

put a value integrator.
in the simplest case resistor + capacitance. select/calculate resistance and capacitance to smooth out pulses of values. you get the average value of the current.
There is an example of a simple filter in the pdf at your link.