I have an MPPT 100/20 regulator connected to a pair of large Canadian solar panels charging 12-off US3000C batteries. Occasionally, the terminal voltage of the panels creeps up to 101V and the regulator throws an alarm via the VE bus. I am fine with this. However, I feel that the MPPT algorithm is flawed requiring revision.
When the voltage exceeds 100V the regulator, rather than intentionally mismatching the source (panel) and load (battery) impedances to force the voltage down, disconnects and the current drops to zero. This is a silly idea for it compounds the problem by making the voltage rise further risking exploding capacitors. The MPPT algorithm should not only impedance match maximising energy transfer panel-to-battery but should also keep a track of the panel voltage and increase the PWM duty factor, intentionally mismatching the impedances, in order to constrain the panel voltage to below 100V in order to avoid alarms and exploding capacitors.
It is appreciated that when the battery is full, the regulator has to disconnect but with a 40 kWhr battery, there is much charging to be done before the MPPT regulator backs off.
There is also no safety factor: as soon as 100 V is reached, the regulator disconnects. I am ok with it alarming at 100 V but there should be some margin before shutting the regulator off to disconnect.
It is not as if the current is high either for the most the panels ever deliver is 6 Amps, which is well below the 20 Amp rating of the regulator.
Suggest a simple algorithmic tweak.
