PG1995
Active Member
Thank you, Steve, NG.
Taking the previous two messages together means that having an inner PID loop makes the system more stable. But the question is how stable does it make the system.
Suppose P&O outer loop updates, say, every one minute, and the inner PID loop updates at a very fast rate. If a cloud is passing above and it takes only 20 seconds to get the sky clear again then inner loop might be able to maintain the input voltage and hence temporary changing conditions doesn't disturb the system and hence a comparatively stable system. But what if the sky takes just more than a minutes to clear, the system will definitely be disturbed because inner P&O loop will change the input voltage. After that the system will stay at this non-optimum input voltage until the inner P&O loop gets updated again. Thank you.
Best wishes
PG
P&O is generally a bad algorithm, which doesn't perform well in changing conditions. A passing cloud can completely derail it.
Therefore, using an inner loop to maintain input voltage at a given value, as Steve suggested, and letting P&O operate at much slower pace, will produce a much more reliable system.
Taking the previous two messages together means that having an inner PID loop makes the system more stable. But the question is how stable does it make the system.
Suppose P&O outer loop updates, say, every one minute, and the inner PID loop updates at a very fast rate. If a cloud is passing above and it takes only 20 seconds to get the sky clear again then inner loop might be able to maintain the input voltage and hence temporary changing conditions doesn't disturb the system and hence a comparatively stable system. But what if the sky takes just more than a minutes to clear, the system will definitely be disturbed because inner P&O loop will change the input voltage. After that the system will stay at this non-optimum input voltage until the inner P&O loop gets updated again. Thank you.
Best wishes
PG