2 minutes ago, weber said:

PWM from the output of the inverter

I assume the PWM part you speak of here is the process by which it shapes a sine wave out of DC (aka a kind of reverse frequency modulation :-) )? In other words this is a 350V cap working quite close to its peak? Or not?

Kind of. PWM (Pulse Width Modulation) is one part of the process, and filtering is the other. This combination can be used for DC-DC conversion as well as DC-AC inversion. The top of this diagram shows the output of the PWM stage (in the Axpert, a full bridge of 4 IGBTs operating from 400 Vdc), and then at the bottom it shows what it looks like after it has been through a filter (in the Axpert, a series inductor (L) followed by a parallel capacitor (C)). PWM operates at a fixed frequency. I think it's around 30 kHz in the Axperts. So there are around 600 cycles of PWM for every cycle of the 50 Hz sine wave (as opposed to 40 in the diagram), and so the output of the filter is way smoother than that shown in the diagram.

Solar charge controller manufacturers have confused people by using the term "PWM" for what are in fact simple on-off controllers. It is the MPPT SCCs that actually use PWM.

Edited December 14, 20187 yr by weber

The capacitor is rated at 350 V AC (presumably that's volts RMS at 50 Hz), so it is operating within its voltage rating. Whether it is operating within its high-frequency ripple-current rating is another question.

Edited December 14, 20187 yr by weber

41 minutes ago, weber said:

 



 

The output of a Multiplus looks pretty similar. I mean you have to zoom in really closely, but when you do you can see just the tiniest bit of a squiggle on the waveform. Additionally on the Multi it looks (at least on my scope) as if the tops of the  sine wave is a little flat, but this was in a completely unladen state.

In other news, I figured out how I can use my scope on the AC-output. I made a plug with a 2 x 1M-ohm voltage divider to get around the max-250V-peak issue of the scope, and then I just leave the earth clamp unused (because it is already earthed and  you don't want to blow things up).

@weber

Hi Guys, anyone tried to make these inverter more robust? I know that they annouced lots of protection but it seems these protection, overload, overcharging etc.. Are not working, this is my second inverter melt down and circuit breaker are not helping. Is there a way to protect them better? Like a current limitter circuit/relay on the AC input output and DC. Also extending this to parallel design? 

2 hours ago, weber said:

 

Solar charge controller manufacturers have confused people by using the term "PWM" for what are in fact simple on-off controllers. It is the MPPT SCCs that actually use PWM.

It is a PWM signal too, round 300 Hz in the Axpert i´m testing. 

Edited December 14, 20187 yr by Javi Martínez

They seem to have got to a point in their development, where there is no single common point of failure, so it is not worth upgrading anything. Just accept that this is a very cheap inverter, about a third of the price of the nearest competitor, so if you have to buy two of them, for every one of the other, you shouldn't complain.

However, if it is connected to the grid, Gnome's reason number 2 above may be worth considering, and so it may be worthwhile installing a modular surge suppressor across the grid, in your switchboard. Such as these:

https://www.hagerelectro.com.au/e-catalogue/energy-distribution/modular-protection-devices/surge-protection-devices/surge-protection-devices/14161.htm

Edited December 14, 20187 yr by weber

You can find a schematic (traced by Coulomb) showing the IGBT drivers, here:

http://forums.aeva.asn.au/viewtopic.php?title=pip4048ms-inverter&p=64476&t=4332#p64476

39 minutes ago, Javi Martínez said:

It is a PWM signal too, round 300 Hz in the Axpert i´m testing. 

That low? Maybe for a PWM controller? In my experience MPPTs usually operate in the tens of Khz usually above 30Khz to avoid being audible. I know on smaller discrete DC/DC modules it might go into the hundreds of Khz, but because skin effect becomes a real problem it's probably not used a lot for MPPTs.

35 minutes ago, plonkster said:

That low? Maybe for a PWM controller? In my experience MPPTs usually operate in the tens of Khz usually above 30Khz to avoid being audible. I know on smaller discrete DC/DC modules it might go into the hundreds of Khz, but because skin effect becomes a real problem it's probably not used a lot for MPPTs.

Yes, it´s a 50 A PWM controller. You´ll never hear anything near an Axpert because of fans...It seems it´s taking off...

On 2018/12/14 at 10:41 AM, Bricoleur said:

@weber

Hi Guys, anyone tried to make these inverter more robust? I know that they annouced lots of protection but it seems these protection, overload, overcharging etc.. Are not working, this is my second inverter melt down and circuit breaker are not helping. Is there a way to protect them better? Like a current limitter circuit/relay on the AC input output and DC. Also extending this to parallel design? 

It would be better if you could redesign your input / output circuits so as not to go over the ratings.

i.e. for overload protection put a smaller circuit breaker in that would trip before the inverter trips. i.e. use a 20A circuit breaker and earth leakage with overload on a 5KVA model. that will give you about 4.4Kw load.

Use surge arrestees, both on the input and output to protect from spikes. I saw one once that was blown due to a faulty vacuum cleaner

And don't over-rate your PV strings by more than the charge controller can handle. i.e. if it's rater for 60A, don't go over it. In fact, try and stay at least 20-30% below it and use fuses that will blow before the inverter blows. On the "good 'ol" Axpert 5KVA you wouldn't really go over about 40-45A on the MPPT side. So use a 12A fuse on each PV string

18 hours ago, SilverNodashi said:

I saw one once that was blown due to a faulty vacuum cleaner

I hope you're not referring to my blowup, that happened to occur when a vacuum cleaner was turned on.

http://forums.aeva.asn.au/viewtopic.php?f=64&t=4332&p=66045#p66045

As it says two posts later, it was not the fault of the vacuum cleaner. The same vacuum cleaner has since been used many times with the repaired inverter.

Update, I ve changed the melted big black Capacitor, two other small ones (C50 & C60) and the inductor which were near the Cap (orange line in picture attached) 

I ve turned on the inverter and:

- good news: voltage ramp up to 230V and stick to this voltage

- bad news the shortcircuit between AC input and output still exist. 

Follow the short circuit and it was not the relay, instead was the transistor in the card (holded by the four large metallic rope rising from the main board, in RED in the attached pic) 

I ve replaced the card (from my existing  burnt board) but the problem persist, infact I think (I am not sure) that the transistor on the new card burnt also once I ve turn on the inverter (no abnormal appearance but the transistor Source and drain well shorted out) 

Then I ve disconnect the card and turn on the inverter, It ran smoothly with 230v output without any error. 

Anyone knows what is the purpose of this card? 

On 2018/12/21 at 8:54 AM, SilverNodashi said:

would be better if you could redesign your input / output circuits so as not to go over the ratings.

i.e. for overload protection put a smaller circuit breaker in that would trip before the inverter trips. i.e. use a 20A circuit breaker and earth leakage with overload on a 5KVA model. that will give you about 4.4Kw load

Thanks for the advice, will sure do once the issue is over. 

On 2018/12/22 at 8:34 PM, Bricoleur said:

Anyone knows what is the purpose of this card?

I don't!   But somehow, it doesn't stop me from guessing. I've long suspected that this card is to do with the faster transfer when you select AC Input Voltage Range (setting / parameter 03) to UPS, rather than the default APL (APpLiance).

I never did get to the bottom of what the firmware does with this setting; it's never been a priority.

I suspect that with the card removed, if you change setting 03 to UPS (edit: was APL), then there will be an error, or it just won't change over as fast as it would have with a working card. That card is referred to as a "parallel power board" in some of the service manuals. This suggests paralleling of machines, of course, but that makes no sense. If it is for paralleling the relays with Triacs or whatever they are, this makes more sense.

Edited December 25, 20187 yr by Coulomb
typo; APL->UPS

1 hour ago, Bricoleur said:

good news: voltage ramp up to 230V and stick to this voltage

Well done!

Thanks Coulomb, 

Is it different from the parrallel card that we have at the bottom of the inverter as my installation is two inverter in parallel. 

I am really worried of connecting it up in parrallel with the other inverter. 

Anyone has the service manual of such (not the user one) 

10 hours ago, Bricoleur said:

Anyone has the service manual of such (not the user one) 

On this very forum:

https://powerforum.co.za/files/file/14-pip-hs_ms_4-5kva_new_service_manual_201506a/

 

Thanks Coulomb, pitty that the service manual doesnt mention anything on this PAR card. 

Anyine knows what it does really, I ve followed it and it seems that twonof the transistors are put in parallel of the relay between Lgrid and L output. 

On 2018/12/14 at 8:41 AM, weber said:

The capacitor is rated at 350 V AC (presumably that's volts RMS at 50 Hz), so it is operating within its voltage rating. Whether it is operating within its high-frequency ripple-current rating is another question.

Considering the inverter stage is the part that usually holds up (and rather the MPPT that kills the whole thing), I would say it is likely not a problem

On 2018/12/22 at 2:30 PM, Coulomb said:

I don't!   But somehow, it doesn't stop me from guessing. I've long suspected that this card is to do with the faster transfer when you select AC Input Voltage Range (setting / parameter 03) to UPS, rather than the default APL (APpLiance).

I never did get to the bottom of what the firmware does with this setting; it's never been a priority.

I suspect that with the card removed, if you change setting 03 to APL, then there will be an error, or it just won't change over as fast as it would have with a working card. That card is referred to as a "parallel power board" in some of the service manuals. This suggests paralleling of machines, of course, but that makes no sense. If it is for paralleling the relays with Triacs or whatever they are, this makes more sense.

Do you mean the other way around? From Appliance to UPS? (ie> more sensitive?)

Any possibility it has something to do with voltage tracking?

In appliance mode the switch time is 25ms (IIRC), equivalent to a full single cycle @ 50Hz negating the need for voltage tracking.

4 hours ago, Gnome said:

Do you mean the other way around? From Appliance to UPS? (ie> more sensitive?)

Duh, yes I do, sorry. Corrected now.

4 hours ago, Gnome said:

Any possibility it has something to do with voltage tracking?

I don't think so. They track the voltage and current all the time (e.g. zero crossing interrupts), so as to synchronise AC in and AC out. That's needed for paralleling, as well as switching somewhere near the zero crossings of load current, though I admit that since APL mode takes a full 20 ms cycle (at 50 Hz), there doesn't seem much point. It's possible that the "value line" models (VM series) don't bother synchronising AC in and AC out. In fact, I've just checked, and the firmware for a VM III has a much simpler SynchroZeroCrossInterrupt() interrupt handler, although LineZeroCrossInterrupt() is essentially the same.

Hello guys, 

My inverter that I fix, and sometime, go into error 52 (low bus voltage), anyone knows what it is ir hiw to fix it? 

Another important point and with another GOOD inverter, when utility goes out and when it comes back, the fridge compressor does a strange noise for 10seconds, anyone knows why and how to fix it, is it something related to zerocrossing voltage source change between inverter and utility? 

 

Hi

I solved 06 error by replacing the power supply capacitor

Now, when I power on the device, the 220V output is available for a few seconds and then output disconnected and it doesn't show any error code on the screen and it does not make any sound from the buzzer.

when I measure the output of 220 volts, it is connected and disconnected every second between zero and almost 90 volts, and a ticking sound comes from the transformer.
What could be the problem?

please guide me.
Regards

7 hours ago, majidzero said:

Now, when I power on the device, the 220V output is available for a few seconds and then output disconnected

My guess is that you have more bad capacitors, and this is causing the power supply to collapse under the increased load of running the DC-AC converter (more gate capacitance to charge and discharge). In an inverter that's more than about 5 years old, it's worth replacing all the electrolytic capacitors in the power supply; see this post for a list of capacitors I replaced.

7 hours ago, majidzero said:

when I measure the output of 220 volts, it is connected and disconnected every second between zero and almost 90 volts,

That might be the inverter soft start function, thought I thought that happened with the output relay off. It seems to ramp up the sine wave amplitude 5 V at a time and check that the output is reasonable.

7 hours ago, majidzero said:

a ticking sound comes from the transformer.

That could just mean it's not mounted robustly, but usually it means that there is significant sudden change in current through the transformer windings. That might be caused by the power supply collapsing, or it might point to something bad in the DC-AC converter IGBTs or their gate drivers.