Hello.

There is a problem. There is a 5 kW inverter. Recently burned transistors and several resistors. I have already replaced them. But now there is another problem in the form of error 52.

It appears when running on batteries.

Step by step:
1 - I run the inverter on batteries only.
2 - I connect the load and increase it step by step.
(I used an ordinary household hair dryer up to 2 kW as a load, 4 steps ~ 100 watts, ~ 300 watts, ~ 700 watts, ~ 2 kW)

Result:
At 100 and 300 watts everything is normal.
At 700 watts, the inverter runs for another 30 seconds, then crashes with error 52.
At 2000 watts, the inverter immediately crashes.

Tell me what, where and how exactly to check? I'm a beginner to say the least.

When working for example from a grid, there are no such problems.

8 hours ago, Abra said:

Hello.

There is a problem. There is a 5 kW inverter. Recently burned transistors and several resistors. I have already replaced them. But now there is another problem in the form of error 52.

It appears when running on batteries.

Step by step:
1 - I run the inverter on batteries only.
2 - I connect the load and increase it step by step.
(I used an ordinary household hair dryer up to 2 kW as a load, 4 steps ~ 100 watts, ~ 300 watts, ~ 700 watts, ~ 2 kW)

Result:
At 100 and 300 watts everything is normal.
At 700 watts, the inverter runs for another 30 seconds, then crashes with error 52.
At 2000 watts, the inverter immediately crashes.

Tell me what, where and how exactly to check? I'm a beginner to say the least.

When working for example from a grid, there are no such problems.

Are you sure your battery is well charged. After a step load over 3kW it could be low  and disconnect battery level. Keep the battery voltage indication open when adding loads. 

8 hours ago, Abra said:

Tell me what, where and how exactly to check? I'm a beginner to say the least.

This may be beyond your capabilities. But I can give some general help.

Fault code 52 means "DC bus voltage is too low". 

In battery mode, the DC bus is fed from the battery via the DC-DC converter. That is a pair of full bridges connected by a high frequency transformer. At the battery end, the full bridge is the set of MOSFETs, driven by the SG3525 chip (in the models I'm familiar with). At the DC bus end, there are 4 IGBTs, also driven by the SG3525 chip. It seems that this DC-DC converter is able to pass a few hundred watts, but not 2 kW, or even 700 W for very long. So something is presumably weak along this path.

There is also a buck converter between the DC-DC output and the DC-AC converter. If this buck transistor (it could be an IGBT, or sometimes a MOSFET) is not turning on properly, or it's damaged, this might cause this problem. Testing at 700 W seems to be your best bet, since it operates for long enough to make measurements. Check the voltage across the buck converter to see if it's where you are losing power. If this is the case, I would expect the buck converter transistor to become extremely hot.

I would check the gate drivers for all power devices (the MOSFETs, the DC-DC IGBTs, the DC-AC IGBTs, and the buck transistor). Use the partial traced schematic diagrams; since you have a 5 kW model, the 5 kVA schematic here is probably the closest.

Edit: But as Scorp007 mentions above, also check that your battery voltage isn't sagging or collapsing under load.

Edited December 16, 20222 yr by Coulomb

8 hours ago, Scorp007 said:

Вы уверены, что ваш аккумулятор хорошо заряжен? После ступенчатой нагрузки свыше 3кВт она может стать низкой и отключить уровень заряда батареи. Держите индикацию напряжения батареи открытой при добавлении нагрузок. 

Yes, because 2 more inverters are working at the same time. The entire house is powered by solar energy. During tests, the battery charge was kept at 52.2v and did not fall below.

At the moment, I have 2 inverters 5kw, 2 blocks of 16 lifepo4 200ah batteries and 48 panels 350w working well. And 2 more inverters have problem. 1 of this 2 I try to repair.

8 hours ago, Coulomb said:

This may be beyond your capabilities. But I can give some general help.

Fault code 52 means "DC bus voltage is too low". 

In battery mode, the DC bus is fed from the battery via the DC-DC converter. That is a pair of full bridges connected by a high frequency transformer. At the battery end, the full bridge is the set of MOSFETs, driven by the SG3525 chip (in the models I'm familiar with). At the DC bus end, there are 4 IGBTs, also driven by the SG3525 chip. It seems that this DC-DC converter is able to pass a few hundred watts, but not 2 kW, or even 700 W for very long. So something is presumably weak along this path.

There is also a buck converter between the DC-DC output and the DC-AC converter. If this buck transistor (it could be an IGBT, or sometimes a MOSFET) is not turning on properly, or it's damaged, this might cause this problem. Testing at 700 W seems to be your best bet, since it operates for long enough to make measurements. Check the voltage across the buck converter to see if it's where you are losing power. If this is the case, I would expect the buck converter transistor to become extremely hot.

I would check the gate drivers for all power devices (the MOSFETs, the DC-DC IGBTs, the DC-AC IGBTs, and the buck transistor). Use the partial traced schematic diagrams; since you have a 5 kW model, the 5 kVA schematic here is probably the closest.

Edit: But as Scorp007 mentions above, also check that your battery voltage isn't sagging or collapsing under load.

Thank you very much for directing me, I will try to look for the problem along this way. I have suspicions that I could purchase and install substandard IGBTs for replacement. Although it seems to have taken the same model.

On 2022/12/16 at 10:24 PM, Coulomb said:

This may be beyond your capabilities. But I can give some general help.

Fault code 52 means "DC bus voltage is too low". 

In battery mode, the DC bus is fed from the battery via the DC-DC converter. That is a pair of full bridges connected by a high frequency transformer. At the battery end, the full bridge is the set of MOSFETs, driven by the SG3525 chip (in the models I'm familiar with). At the DC bus end, there are 4 IGBTs, also driven by the SG3525 chip. It seems that this DC-DC converter is able to pass a few hundred watts, but not 2 kW, or even 700 W for very long. So something is presumably weak along this path.

There is also a buck converter between the DC-DC output and the DC-AC converter. If this buck transistor (it could be an IGBT, or sometimes a MOSFET) is not turning on properly, or it's damaged, this might cause this problem. Testing at 700 W seems to be your best bet, since it operates for long enough to make measurements. Check the voltage across the buck converter to see if it's where you are losing power. If this is the case, I would expect the buck converter transistor to become extremely hot.

I would check the gate drivers for all power devices (the MOSFETs, the DC-DC IGBTs, the DC-AC IGBTs, and the buck transistor). Use the partial traced schematic diagrams; since you have a 5 kW model, the 5 kVA schematic here is probably the closest.

Edit: But as Scorp007 mentions above, also check that your battery voltage isn't sagging or collapsing under load.

It seems that the problem is in the Mosfet transistors. The transistors do not heat up, and when measured in the off state, the readings approximately correspond to the data from this manual ( https://forums.aeva.asn.au/uploads/4111/Copy_of_PIP-HS_MS_4-5KVA_new_Service_manual_201506A.pdf ), but for some reason the voltage drops. Maybe I bought some weird new transistors.... I don't know. But I'll try to change them to the same. 

Maybe you can advise which transistors to install, can somehow improve the device? The original ones were:

Yep, fixed!

The problem was bad transistors. Maybe my bad choice...

Here are the ones I bought as replacements:

In the near future I will need to repair another one of the same inverter. Could you advise me which transistors are better to buy? So that I don't make a mistake again.

2 hours ago, Abra said:

Could you advise me which transistors are better to buy?

I highly recommend using 100 V parts, and better capacitors to protect them. This was all discussed (some years ago now, so availability may have changed, and better parts may now be available) in the repair and hardware modifications topic; see in particular Weber's post about upgrading the capacitors and MOSFETs. When MOSFETs switch into circuits with leakage inductance, there are spikes of voltage which need to be absorbed by the capacitors across the battery bus. The ones supplied by Voltronic aren't the worst, but they are far from the best, and will fail after a number of years of operation, especially if the environment is hot. Fans being installed in the wrong direction doesn't help either (another recommended modification discussed in the modifications topic).

12 hours ago, Coulomb said:

I highly recommend using 100 V parts, and better capacitors to protect them. This was all discussed (some years ago now, so availability may have changed, and better parts may now be available) in the repair and hardware modifications topic; see in particular Weber's post about upgrading the capacitors and MOSFETs. When MOSFETs switch into circuits with leakage inductance, there are spikes of voltage which need to be absorbed by the capacitors across the battery bus. The ones supplied by Voltronic aren't the worst, but they are far from the best, and will fail after a number of years of operation, especially if the environment is hot. Fans being installed in the wrong direction doesn't help either (another recommended modification discussed in the modifications topic).

Got it, thanks a lot!

Now I have fully assembled and installed this inverter. There seems to be no errors, but as for power from solar panels. It seems to me that something is wrong. When the normal 2 inverters show 600w+ (Today is a very cloudy day), the repaired inverter shows ~50w

 

And somehow the output voltage began to jump (220-240), although other inverters without repaired invertor hold ~228-232

I tried to change SCC board from another inverter, the same... I think problem somewhere in main board... I tried to change mode to "snu" (Charging from solar and utility same time), but charging still not working. It looks like it working (2 icons ac and pv on a screen), but on a screen 0A, and ~50watts to battaries. Also I think power from solar not going to AC output.

In my experience:

input AC to output AC working well
input AC to batteries not working
input solar to output AC not working
input solar to batteries not working
batteries to output AC working well

Edited December 19, 20222 yr by Abra

1 hour ago, Abra said:

input solar to output AC not working

If it wasn't for the above, I'd suspect the buck transistor and its associated gate drivers. In your model, it is involved with all battery charging.

It's probably worth checking anyway.

On 2022/12/19 at 3:17 PM, Coulomb said:

If it wasn't for the above, I'd suspect the buck transistor and its associated gate drivers. In your model, it is involved with all battery charging.

It's probably worth checking anyway.

I tried to check all around Q32 (If I understand correctly which transistor is meant), but i think it's working well....

R125 46.9ohm
R123 34.7kohm (48.4kohm when I desolder it)
D9 (Desolder) 0.6, 0L
R183 100ohm
R168 1komh
R165 0.5komh
R157 0.5komh
R182 220ohm
D25 (Desolder) 0.6, 0L

Q5, D44 - ok

C45, C43 charging

About U12, I compared the resistance readings on all legs with neighboring same microcircuits and with the same microcircuit on another board (The charging node works there, but the problem is different). Readings match

Also i tried to replace Q32 with origin one from another inverter. Nothing...

Edited December 21, 20222 yr by Abra

Look, this is the behavior of a working inverter:

 

1st step - pv off:

 

2nd step pv on (around 5 seconds ~25w):

 

3rd step - pv on and working:

 

I think broken iverter stuck on 2nd step. 3rd step isn't start.

Edited December 21, 20222 yr by Abra

50 minutes ago, Abra said:

Look, this is the behavior of a working inverter:

 

1st step - pv off:

 

2nd step pv on (around 5 seconds ~25w):

 

3rd step - pv on and working:

 

I think broken iverter stuck on 2nd step. 3rd step isn't start.

Were step 2 and 3 pictures taken this morning? Please give the time of day taken. 

5 minutes ago, Scorp007 said:

Were step 2 and 3 pictures taken this morning? Please give the time of day taken. 

These are screenshots from a 10 second video. Recorded everything in a row, within 10 seconds.

Shooting time 11 am (an hour ago), very cloudy day:

2 hours ago, Abra said:

These are screenshots from a 10 second video. Recorded everything in a row, within 10 seconds.

Shooting time 11 am (an hour ago), very cloudy day:

When you switch on the PV the charge will be low like 25W. As the MPPT ramps up to say your 400W could happen in 30-60seconds. This is very normal. 

1 hour ago, Scorp007 said:

When you switch on the PV the charge will be low like 25W. As the MPPT ramps up to say your 400W could happen in 30-60seconds. This is very normal. 

Yes, this is a photo of a normal, fully working inverter. After connecting the PV, it receives 25 watts, after 5 seconds it starts to work completely. But the non-working inverter only reaches 25 watts, but after that it does not start working, although the screen shows that everything is working, only the inverter does not start to receive full power from PV.

A non-working inverter can only take the first 2 screenshots, but it doesn't get to the third one. And I can’t understand what doesn’t start in it and where can I check?

Edited December 21, 20222 yr by Abra

8 hours ago, Abra said:

I tried to check all around Q32 (If I understand correctly which transistor is meant)

Yes, that's the buck transistor. Only in the oldest models do they actually have two transistors in parallel.

8 hours ago, Abra said:

About U12, I compared the resistance readings on all legs with neighboring same microcircuits and with the same microcircuit on another board (The charging node works there, but the problem is different). Readings match

Yeah, that one really needs testing on the bench with clip leads and power supplies. But those driver chips rarely fail in my limited experience, so I think you've all but eliminated the buck stage as a culprit.

2 hours ago, Abra said:

And I can’t understand what doesn’t start in it and where can I check?

I assume you've checked the charging and battery voltage settings (settings 16, 26, 27). Is the battery voltage close to what a multimeter reads at the battery terminals?

The fact that you get 25 W of charge power (one amp at 25 V) suggests that the Solar Charge Controller is largely working. Do you have monitoring software that can report the battery voltage as read by the Solar Charge Controller?

4 hours ago, Coulomb said:

I assume you've checked the charging and battery voltage settings (settings 16, 26, 27). Is the battery voltage close to what a multimeter reads at the battery terminals?

The fact that you get 25 W of charge power (one amp at 25 V) suggests that the Solar Charge Controller is largely working. Do you have monitoring software that can report the battery voltage as read by the Solar Charge Controller?

 Yes, all three inverters that I work in conjunction at the moment (Including the one that does not charge) have identical settings, including 16, 26 and 27

The battery voltage, which is shown on the screens of all three inverters, including the broken one, is approximately the same, can vary within 0.2V

Unfortunately, I have no way to get data from BSM. But they are working properly at the moment, based on the fact that the other 2 inverters are more than adequately working with batteries.

This is what my system installation looks like at the moment (Not including wires to solar panels, AC inputs and outputs and communications between inverters via a parallel connection board):

 

I want to remind that according to my observations, these functions work / do not work for the third inverter after repair:

input AC to output AC working well
input AC to batteries not working
input solar to output AC not working
input solar to batteries not working
batteries to output AC working well

My feeling is that the breakdown looks like some kind of transistor simply does not turn on to start charging, both from the AC input and from the PV, but at the same time, the screen shows that charging is in progress and the Charging light is flashing. Those watts that the inverter receives from the PV input feel like they go to the work of the inverter, so I see them on the screen as PV Input. At the input from the solar panels, I have ~ 230v, up to 18 amperes, for each inverter there are 12 (in series + parallel) panels of ~ 38 volts up to 9 amperes. The voltage readings on all inverters, including the broken one from solar panels, are approximately the same.

Also, for example, if all three inverters are connected in parallel, and at the moment the batteries are fully charged and the sun is enough to power the whole house, then the screen on the BAT output of the first two inverters shows 0 amperes, and the house is powered by solar panels, and on the third, the house is powered only from batteries, for example, it writes 18 amperes at the output from the batteries, although there are more than enough solar panels. Therefore, the energy from the solar panels is not supplied to both the batteries and the AC output.

It is still difficult for me to understand what is happening, but I try to convey the situation as accurately as possible.

 

 

A long shot: have you checked setting 31 on all three inverters, "Solar power balance"? It should be enabled (I can't think why it should ever be disabled). If disabled, per the manual: "If selected, the solar input power will be same [ as ] max. battery charging [ current ], no matter how much [ load is ] connected". Now that I re-read this, it doesn't sound relevant, but it's probably worth a check.

4 minutes ago, Coulomb said:

A long shot: have you checked setting 31 on all three inverters, "Solar power balance"? It should be enabled (I can't think why it should ever be disabled). If disabled, per the manual: "If selected, the solar input power will be same [ as ] max. battery charging [ current ], no matter how much [ load is ] connected". Now that I re-read this, it doesn't sound relevant, but it's probably worth a check.

Yep, 31 -> SbE

Now I tried to connect the inverter using only solar panels.

The inverter has turned on, a BP error has occurred, respectively, because I did not connect batteries.

Next, I pressed the inverter enable switch and after a while error 15 (PV energy is low) appeared, which again means that there are problems. Where and how to measure what is the problem and where is the energy lost?

p.s. at the time of switching on, the sun was bright enough and neighboring inverters showed more than 2KW incoming from the panels.

I change SCC board from another inverter, the same. 

 

Measurements show:

250v (input from solar)

250v between w18,w19 (On main board)

Edited December 22, 20222 yr by Abra