DC Genset - I've gone and over-complicated things
Posted: Sat Dec 26, 2009 3:25 pm
I've been using MrAl's circuit with my DIY genset for some time now, it works well for the 12v setup I had initially.
However, in the 48v system I'm experimenting with now, I've run into some trouble. There are now four of the MrAl-gulators controlling each of the four alternators and the PID tuning has become vastly more complex with the batteries wired in series. I'm running into situations where I'm either charging one of the batteries too much/little or I exceed the upper voltage limit of my inverter (68v) and its protection mechanisms kick in. Add load variations like a well-pump turning on and off and I'm finding my control algorithm simply can't respond in time. To get around the problem, I've tweaked a regulator circuit I found while Googling and came up with this:
It will allow me to set an upper voltage limit with a digital pot. However, it doesn't let me set a charge rate as it works much like a mechanical voltage regulator does (it's either on or off). So, used by itself, I won't be able to vary the current flowing into my AGM batteries (C/5 or ~20a is the recommended charge rate).
My thought was to wire MrAl's and the latest one together in series (the MrAlgulimiter) on the field coil so I have control over an upper voltage limit and over the charge rate for each battery, but it's not working out that way. I'm misunderstanding the way these circuits work both individually and together, thus I can't get the right amount of current flowing through RField in my simulation:
(note: the voltage-controlled pots are the closest thing I could find to a AD5204)
My guess is I've made the circuit more complicated than it needs to be. Is there a way to combine the output of U1 and U4 before the 2n2222 and use just one TIP3055?
However, in the 48v system I'm experimenting with now, I've run into some trouble. There are now four of the MrAl-gulators controlling each of the four alternators and the PID tuning has become vastly more complex with the batteries wired in series. I'm running into situations where I'm either charging one of the batteries too much/little or I exceed the upper voltage limit of my inverter (68v) and its protection mechanisms kick in. Add load variations like a well-pump turning on and off and I'm finding my control algorithm simply can't respond in time. To get around the problem, I've tweaked a regulator circuit I found while Googling and came up with this:
It will allow me to set an upper voltage limit with a digital pot. However, it doesn't let me set a charge rate as it works much like a mechanical voltage regulator does (it's either on or off). So, used by itself, I won't be able to vary the current flowing into my AGM batteries (C/5 or ~20a is the recommended charge rate).
My thought was to wire MrAl's and the latest one together in series (the MrAlgulimiter) on the field coil so I have control over an upper voltage limit and over the charge rate for each battery, but it's not working out that way. I'm misunderstanding the way these circuits work both individually and together, thus I can't get the right amount of current flowing through RField in my simulation:
(note: the voltage-controlled pots are the closest thing I could find to a AD5204)
My guess is I've made the circuit more complicated than it needs to be. Is there a way to combine the output of U1 and U4 before the 2n2222 and use just one TIP3055?