Hello all. The above is a circuit schematic (sorry for poor hand drawing) for monitoring power from 3-phase AC generator. The main goal of the circuit is to see how the power output varies depending on the load resistance that control the generator torque. Here are my questions.
I though that when I control the PWM duty cycle, I could control the value of resistance. I verified that the resistance actually changes. But the current output is really oscillating, whereas the voltage output is pretty stable. Some people saids that connecting capacitor would reduce the fluctuation, but it seems not to work. Once I average the current value over, say 60sec, I could get the kind of representative value. However, I really wonder if there is a certain way to regularize the current output?
I am always having difficulty to understand the role of ground in a circuit. In the above figure, do I need to connect the negative pin of the generator (rectifier) to the ground pin of the Arduino board? I am really reluctant to do that worrying about something wrong will happen.
Finally, is there any way to monitor power from 3phase generator more efficiently? I am feeling that using rectifier causes some energy loss as well as block the natural relationship between the load resistance and the output power.
Thank you very much.