I am trying to design a protection circuit for wind turbine. It suppose to stop turbine rotating when wind speed is to big. I came up with this circuit.
simulate this circuit – Schematic created using CircuitLab
Comparator should be enabled immediately after about 120V is detected and hold it's state for about 15 to 20 minutes regardless of the change in it's input voltage. But I was told that this ADC from micro-controller would be getting incorrect voltage information due to C1 charging through R1 in case of fast change in turbine voltage. What can be done to eliminate this problem. Could simple voltage follower before D1 work?
Second problem is the input offset current in opamp. It can charge C1 and lead to unintended enabling of comparator. Is there a simple way to eliminate this issue? Maybe find a opamp with low offset?
Thanks for help!