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Oliver avatar image
Oliver asked

AC Coupling and BYD premium LVL 15.4

Hello,

I would like to know if there is any possible way to speed up frequency regulation by modifying the settings of the PV inverter assistant.

The system is off grid and consists of

- BYD LVL premium 15.4

- Bluesolar MPPT 150/60

- Quattro 48/8000

- Solaredge SE6000H (maximum expected PV-contribution is << 4500W)


The P(f) ramp at the Solaredge side is defined from 50.2Hz to 51.7Hz and disconnect @ 52Hz.

The Victron PV-Inverter assistant is configured for the same band with disconnect @ 52.1Hz. With 6000W inverter and 6400W PV.

I observe that once 55.2V are reached BYD sets the charging parameter to zero. However charging continues as the frequency ramp only rises slowly and therefore the SE inverter does not reduce its output fast enough. For now I throw off (via AC-OUT 2) the SE inverter once the voltage gets higher 57V. By that time frequency has only risen to 50.4Hz. Can the ramp rise time be shortened? Am I too carefull with the 57V limit? (cell details show almost 3.8V for the highest cell). Thank you in advance for your help and input!!

AC PV CouplingBYD
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1 Answer
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Have you tried with the default parameters that are set in the AC PV inverter assistant in VEConfigure (i.e disconnect at 53 hz).

That should work, and be fast enough.

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Oliver avatar image Oliver commented ·

you mean only changing the disconnect value to its default 53V? The "reduce to minimum" I leave at 51.7Hz as otherwise the SE will certainly disconnect (@ 52Hz) quite often?

By the way, should I have VbatSense of the Quattro connected or is this irrelevant for the regulation (DVCC is selected though)?

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ Oliver commented ·

I would first try with the default settings, and then make adjustments from there once the most important factor (not going over voltage) is sorted.

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Oliver avatar image Oliver Guy Stewart (Victron Community Manager) ♦♦ commented ·

I tried several settings, the one that came closest but still fails in occasions, especially when no AC load is present and battery almost full: SE inverter P(f) ramp from 50.2Hz to 51.2Hz: PV-inverter assistant: 50.2Hz to 52.5Hz and disconnect at 53Hz. Battery voltage still rises faster than frequency. If I don´t control AC Out 2 the BMS of BYD kicks in and produces a spike (66V) which leads to overvoltage (overload) shutdown of the Quattro and frequency lock at 53Hz after recovering. I would prefer avoiding to stress the equipment this way. I will ask in a new post about effects of PV-assistant settings on the generation of the frequency ramp.

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