| ??? 02/19/05 16:49 Read: times |
#87971 - Control System Responding to: ???'s previous message |
Prahlad J. Purohit said:
My Controller system has input -> Thyristor Firing Angle and Output The Welding current. The input is to be adjusted to get the desired output. And for this purpose the feedback coming from Rogogwski coil is used.
I am not convinced with idea of using a higher order system. Do I really need a PI or PID control? Maybe not. The first thing to do is check your maths routines. In one of your previous posts you said: - The next firing delay is calculated as follows...
new RMS factor = Previous cycle RMS factor * target current / measured current in previous cycle. then from table the next firing delay corresponding to new rms factor is determined. Can you post the code that does this calculation? It is possible there are rounding errors that are part of the problem. Ian |
