Waterman Posted February 22 Share Posted February 22 Been away to Ohio the past two weeks and when I got home the inverter said "reversed transformer polarity". How the heck did the power company manage to do that? The inverter had been working fine up till then as wired up. Did they spike the line when they had a power failure to get it backwards? Specs: Rev A Sean rebuilt to Rev C 24V 6K unit. Powered off and then back on and working fine. Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted February 22 Share Posted February 22 "Xformer Polarity" is likely what you saw. What firmware version is the inverter running? (OUT page -> Enter -> down 3x -> Diagnostic -> top 2 lines, which should be the same) It's worth noting that I've put a lot of safeties on the AC input code due to potential severe issues--which has historically been somewhat tricky. I've relaxed safeties on more recent firmware updates, finding that they were a bit too tight for their own good. (Oftentimes, dirty power or glitches would result in Xformer Polarity or other errors.) Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted February 22 Share Posted February 22 basically, if the phase between the input AC voltage and the drive direction is reversed, that's an error (as the synchronous FET drive in AC input mode will result in a deadshort through the low-side FETs -> this will cause FET failure, which is why it's an error). Ideally, this error would only be triggered if the inverter was internally wired wrong. But it seems to be a tad too sensitive on older firmwares...causing it to trip on power line glitches. Quote Link to comment Share on other sites More sharing options...
Waterman Posted February 24 Author Share Posted February 24 It is running Version 1.1r6 Quote Link to comment Share on other sites More sharing options...
Nilao Posted February 24 Share Posted February 24 Mine would do this of the power flickered for a split second longer than it took to switch from ac in to ac out. Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted February 24 Share Posted February 24 8 hours ago, Waterman said: It is running Version 1.1r6 I'd suggest updating to 1.2r1 (latest)...hopefully this will resolve the issue! 3 hours ago, Nilao said: Mine would do this of the power flickered for a split second longer than it took to switch from ac in to ac out. Same...try updating to the latest. Several customers who could reliably reproduce "Xformer Polarity" or "Input Fault" errors have reported no further errors after updating to 1.2r1 (@NotMario no GS inverter errors on any recent powerline recloser activity, right?) Plus some new bells and whistles in there anyway...including a completely redesigned local server page (if you're coming from 1.1r6) 😉 1 Quote Link to comment Share on other sites More sharing options...
NotMario Posted March 1 Share Posted March 1 (edited) @Sid Genetry SolarCorrect. There have been quite a few recloser events with recent weather activity - the GS has handled the events just fine with a short blip. I have nearly 4MWh on the GS now. Bear in mind that my issue was "low output voltage" - not reverse transformer. My only gripe that remains is the blip causes all of my electronics to reset. Wonder if that could be resolved by "anticipating" the load by looking at the load while on passthru, then correlating that with a predefined curve for low-voltage AC side, instead of simply titrating up from 0. For those who don't know what reclosers are - they are why when you have a power outage, you'll often get a few 1-5 second blips with the power coming on and off. They are circuit breakers that will attempt to "reclose" to "burn off" the short before finally giving up and staying open. My low voltage error was caused during the "burn off" timer, where the short is enough to drop the voltage below the GS's threshold. Edited March 1 by NotMario 1 Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 1 Share Posted March 1 44 minutes ago, NotMario said: Wonder if that could be resolved by "anticipating" the load by looking at the load while on passthru, then correlating that with a predefined curve for low-voltage AC side, instead of simply titrating up from 0. To some extent yes...and to some extent no. The biggest issue is that "slamming" a toroidal transformer onto line power (without a soft start)...can result in a big enough kick to literally trip a standard 15A circuit breaker. (Done it myself multiple times...flip a power strip on with a transformer connected, and immediately trip a circuit breaker.) So yes, it is in the plans to get seamless line-to-battery ATS transitions by doing basically what you suggested (although open-ended on the FETs instead of full-driven, otherwise it will blow the FETs out at the start of the ramp)...but the crucial difference is that this will be taking place while line power is still present. It'll just smoothly throttle up until the input line current is zeroed out, then (theoretically) be able to transfer that throttle value directly over to the "normal inverter mode" throttle value and disconnect the input AC via the onboard relays. When line power is already gone (as with a detected power outage), I don't think it'd be wise for inverter longevity to "slam" the voltage back up immediately--that transformer kick could very easily end up blowing the FETs out even with no load on the inverter. Worth noting that the "desired inverter throttle" is affected far more by battery voltage than by loads. And transformer temperature will figure quite significantly in that equation as well (due to the wire temperature coefficient). To precisely identify the "desired throttle" will require some pretty extensive math on top of the inverter gathering runtime variables to determine the unique transformer and system parameters. Quote Link to comment Share on other sites More sharing options...
NotMario Posted March 1 Share Posted March 1 Oh yeah. I was sure there would be a lot more to it than just load - figured my simple phrasing would get the idea across. It wouldn't take much to get into the Goldilocks zone. About power-loss recovery. I wonder how it is that so many simple inverters seem to handle this scenario so well. My Sigineer is LF and it kicks in fast enough to barely be noticeable - though the power is significantly lower... 1 Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 2 Share Posted March 2 2 hours ago, NotMario said: About power-loss recovery. I wonder how it is that so many simple inverters seem to handle this scenario so well. My Sigineer is LF and it kicks in fast enough to barely be noticeable - though the power is significantly lower... We can definitely experiment around and tweak the code a bit...but I'd hate to get to the point of random inverter failure as a result of pushing things a bit too far. Betcha the Sigineer has an E-core transformer in it--those things are SO lossy that there's almost no risk to slamming them into an AC power rail. Quote Link to comment Share on other sites More sharing options...
NotMario Posted March 2 Share Posted March 2 I agree. Yeah, i'm pretty sure it has a square-shaped transformer of some kind. How ironic that inefficiency could be an asset for certain scenarios. So let me try and understand here. Is the issue that it's risky to begin inverting right after an outage because of the magnetic field collapsing - potentially in opposition? I'm confused about why this is different than when the ATS opens. On the other hand, an optional timer to restore-power would resolve the issue with power-protection faults. (where a power supply refuses to resume after a significant, but very short blip - usually occurs with electronics) Hold off for an additional 750ms and it would look more like a recloser event to the devices (to which engineers are more used to making their devices tolerant) and reduce the chance of faults that require manual intervention. Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 2 Share Posted March 2 2 hours ago, NotMario said: So let me try and understand here. Is the issue that it's risky to begin inverting right after an outage because of the magnetic field collapsing - potentially in opposition? I'm confused about why this is different than when the ATS opens. The issue is the extremely low leakage when connecting a toroidal transformer to power...like I've mentioned before, if you just "click on" even a GS6 toroidal transformer secondary directly to the AC mains with a switch, many times it will instantly trip an upstream 15A circuit breaker. (A circuit breaker, mind you, that won't trip with a circular saw's startup surge.) The issue is that if the FETs encounter this, you might as well kiss 'em good-bye: they're going to blow up (if not get partially damaged, and cause a random failure down the road). I am suspecting this may have to do with the position of the AC input phase upon immediate restart--in other words, that the breaker trips if you happen to "slam" the transformer directly onto the peak of the AC wave...and by deduction it should theoretically be fine if the transformer was connected at the zero crossing. If that is the case, then theoretically it would be OK to directly start the transformer from a zero crossing to full amplitude. Here's a 'scope shot I took of testing a PJ ASL4 "48v" transformer primary against an 8650DPM Juntek DC-DC bench supply: Yellow is voltage, purple is current (registered through a PJ "big" current sensor). Notice that the transformer reaches basically a dead short (current flies through the roof, and voltage plummets back to zero) in less than 2mS when presented with a high dv/dt (i.e. slammed into a 55vDC supply!) Conversely, an AC half-wave is 8.33mS--so you can easily see the issue here: if the transformer saturates due to whatever reason, you might as well say "bye bye FETs." Especially on the GS12, where the transformer's 48v dead-short primary calculates out to MORE than 19,200A (and that's not a typo, either. Yes, nineteen-thousand two-hundred amps. FETs are only good for 8,000A if you try to use the 10uS "surge" rating!) Especially in your case with a 24v inverter, it's possible that the "ramp up" is taking longer than expected due to the batteries' ESR (as a result of the higher amperage than with a 48v inverter). I know it's going to be basically impossible to capture, but if you can get a shot of the "DVLT" 'scope screen on a recloser event, that would be highly valuable for visualizing exactly how long the inverter's actually taking to regain output voltage on a power loss event. Quote Link to comment Share on other sites More sharing options...
pilgrimvalley Posted March 3 Share Posted March 3 What is the effect of ESR in capacitor? At the input, increasing ESR increases high frequency noise across the capacitor, decreasing filtering effectiveness. At the output, higher ESR causes more ripple, influencing stability of the control loop. ESR is particularly important in applications with low duty-cycle, high-frequency current pulses. one ofthe GS inverter design flaws is the lack of a soft start / restart up and may even occur in a low battery situation....as well as when switching from the grid connection....????? if the inverter shuts down and all your food rots that would be bad....or your heat source dies do to a inverter malfunction in the frigid winter that would also be real bad this is not a good situation at all... PowerJack also had issue with the battery charger functions some people reported .... I personally never used that in any PowerJack ( charger function/ATS ) just use the inverter as an inverter.... i use a separate battery charger and separate solar charge controllers... all are powered off-grid with solar PV panel generated electricity.... hooking up to the grid with the inverter needs to be UL approved in most all localities in the USA, with approved plans and permits from the local authority having jurisdiction. one could get red-tagged for gorilla hook ups or worse for illegal grid connections..... Sigineer inverter users never report this problem,,,,maybe you can copy their design some... Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 3 Share Posted March 3 1 hour ago, pilgrimvalley said: one ofthe GS inverter design flaws is the lack of a soft start / restart up and may even occur in a low battery situation Says someone who doesn't even have a GS inverter......... ...auto-restart on battery UVP/OVP, overheat, and even from overload has been an available feature since the very first sold GS inverter. Try finding those features on a PJ inverter. 1 hour ago, pilgrimvalley said: if the inverter shuts down and all your food rots that would be bad....or your heat source dies do to a inverter malfunction in the frigid winter that would also be real bad I'm assuming your PJ inverters are much better in these situations, no? Honestly, the reason certain situations result in a shutdown error...is because they are intended to detect/protect against unit failure due to a serious problem or even an internal/external wiring fault. You don't want to "auto restart" into such a fault--because to do so will eventually damage the inverter. For example, if the transformer polarity is backwards, to drive the FETs into battery charge will result in instantly destroying the entire bank of FETs--because they'll literally be shorting out the AC line. So I do realize that I've had some "trips" a bit too trigger happy. And that's what further firmware modifications and updates are working to resolve. Quote Link to comment Share on other sites More sharing options...
pilgrimvalley Posted March 3 Share Posted March 3 (edited) i am observing the problems of the gs designs... to avoid these problems.... sigineer has some stout units as multiple reviews have stated i hope the new 30000 watt PowerJack LF PSW SP module AMG4 version with its new features will be good....still to be determined though... i will hope you can cure your gs inverter from doing the things described above in the future and not continue to blow out all the mosfets on the gs12k....so then 2 of the inverters would not have to be bought to be a redundant failsafe inverter system... the people in the forum are describing issues with the old 6k made from PowerJack manufacturing company... but the 12k prototype is still being changed and needs to be a proven design... Edited March 3 by pilgrimvalley add information Quote Link to comment Share on other sites More sharing options...
pilgrimvalley Posted March 3 Share Posted March 3 8 hours ago, Sid Genetry Solar said: I'm assuming your PJ inverters are much better in these situations, no? I only had one inverter turn off via the LiFePO4 battery's BMS for low voltage and I recharged the battery from another fully charged battery using the Riden 6018 with a different PowerJack inverter.....i did not turn the PowerJack inverter back on until the battery was over 80 percent SOC, so really never saw the reverse polarity etc as i do not utilize the grid connection to any PowerJack inverter at all... my concern is always to protect the expensive LiFePO4 battery 1st.... better???? , i can't say i had the exact failure commentors described in the gs6k inverters in any PowerJack inverter,,,,,knock on wood and I have never blown all the mosfets up or any mosfets for that matter (again knock on wood) I do not totally understand all these things either,,,, but hopefully you will get to the point of producing an inverter ready to ship....via all the new suppliers etc.... I am not an electrical engineer, or a licensed electrician >>>.just learning as I go....trying to avoid major catastrophes.... Quote Link to comment Share on other sites More sharing options...
NotMario Posted March 3 Share Posted March 3 (edited) On 3/2/2023 at 9:45 AM, Sid Genetry Solar said: I am suspecting this may have to do with the position of the AC input phase upon immediate restart--in other words, that the breaker trips if you happen to "slam" the transformer directly onto the peak of the AC wave...and by deduction it should theoretically be fine if the transformer was connected at the zero crossing. If that is the case, then theoretically it would be OK to directly start the transformer from a zero crossing to full amplitude. Notice that the transformer reaches basically a dead short (current flies through the roof, and voltage plummets back to zero) in less than 2mS when presented with a high dv/dt (i.e. slammed into a 55vDC supply!) Conversely, an AC half-wave is 8.33mS--so you can easily see the issue here: if the transformer saturates due to whatever reason, you might as well say "bye bye FETs." Especially on the GS12, where the transformer's 48v dead-short primary calculates out to MORE than 19,200A (and that's not a typo, either. Yes, nineteen-thousand two-hundred amps. FETs are only good for 8,000A if you try to use the 10uS "surge" rating!) Very interesting information. Bearing in mind my limited knowledge in this arena, and i'm theorizing based on some basic principals... Seems like others suggest switching at the peak? https://www.te.com/usa-en/products/relays-contactors-switches/relays/intersection/zero-crossover-switching-transformers.html?tab=pgp-story This would kind of make sense to me because the transformer would already be at full potential, so no surge current necessary to restore it. Unfortunately, i don't think this could work for power-loss recovery. On the other hand, it seems to me something similar to "parallel" mode could be useful for outage-recovery. The fets could track with the grid's wave, a large current increase felt by the fets (indicating the input voltage dropped or went out of phase) could then disengage the ATS. The fets would only be taking the load the original input was handling - the transformer never lost it's field? If my thinking is sound (probably not :D), maybe zero export grid tie (rather the mechanism behind it) would kill 2 birds with one stone. On 3/2/2023 at 9:45 AM, Sid Genetry Solar said: Especially in your case with a 24v inverter, it's possible that the "ramp up" is taking longer than expected due to the batteries' ESR (as a result of the higher amperage than with a 48v inverter). I know it's going to be basically impossible to capture, but if you can get a shot of the "DVLT" 'scope screen on a recloser event, that would be highly valuable for visualizing exactly how long the inverter's actually taking to regain output voltage on a power loss event. I believe you're saying the sudden load causes a voltage drop on the batts which "counters" the inverter's ramping algorithm? I have been investigating this possibility. One hangup i have is the fact that low load is more likely to cause issues. Edited March 3 by NotMario Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 4 Share Posted March 4 1 hour ago, NotMario said: Seems like others suggest switching at the peak? https://www.te.com/usa-en/products/relays-contactors-switches/relays/intersection/zero-crossover-switching-transformers.html?tab=pgp-story That's a very, very interesting document. They do rather succinctly go over why I don't want to "slam" the inverter transformer with the FETs after AC power loss...because huge surge loads like that are on the high voltage side! 400A on the high voltage side (of a 500W E-core transformer...not a 6,000W toroid!) multiplied by the transformer ratio on the low voltage side...yeah, that might not end very well. Several years back when first trying to sort out the ATS transfer functions, I did some diagnostics along these lines--and came to the same conclusion as the above document but with a twist. Engaging the relays at the peak of the AC wave was the best spot--BECAUSE by the time the mechanical relay contacts closed, we were at the zero crossing point. In my testing along those lines, switching the transformer at zero crossing had a significantly lower "inrush spike" than high-peak switching. Does beg the question, "where is the AC wave when a 6kw toroidal transformer connected to mains causes a 15A breaker to trip?" Of course, the newer firmwares on the GS inverters do a seamless transfer from battery -> AC mains, so there is no inrush there anyway--as power never is disconnected. 1 hour ago, NotMario said: On the other hand, it seems to me something similar to "parallel" mode could be useful for outage-recovery. The fets could track with the grid's wave, a large current increase felt by the fets (indicating the input voltage dropped or went out of phase) could then disengage the ATS. The fets would only be taking the load the original input was handling - the transformer never lost it's field? If my thinking is sound (probably not :D), maybe zero export grid tie (rather the mechanism behind it) would kill 2 birds with one stone. Great thinking....but unfortunately there's one critical caveat... If there's a power outage situation, the inverter must disconnect itself from the power input BEFORE attempting to drive power to the output. Otherwise the inverter will end up trying to backfeed the entire local power grid--which will result in an overload shutdown and/or an "Output Shorted" shutdown. (Not to mention completely failing U.L. requirements!) And the disconnect device (AC mains relay) is a mechanical device, meaning that it will take time to physically disengage before the FETs can be driven. This is where the catch-22 comes in: we don't shut off the AC mains relay unless AC power is lost--but once AC power is lost, we now already have a glitch that we don't want on the output! Which is why the best solution is going to be to try to reduce the "glitch" delay. (Worth noting that the methodology you've described is the basic operational premise between the [future!] seamless AC mains -> battery transition code.) If you can capture a shot of the "DVLT" 'scope channel on a recloser event (or just yanking AC input power to the inverter!), that'll give me a good look at what's actually going on--and help determine how much it can be tightened up. Quote Link to comment Share on other sites More sharing options...
JIT Posted March 4 Share Posted March 4 (edited) General rules of thumb is zero voltage turn on for resistive and capacitive loads and peak voltage turn on for inductive (e.g. transformer) loads. Transformers can have additional issues due to remanence mentioned in the TE article. Sudden turn off can cause remanence. Generally, soft start helps minimize turn on issues and soft stop stop helps minimize turn off issues for inverter transformers. However, this is not always practical if the inverter has to provide UPS functions. In addition, inverter drive imbalance can cause remanence to build up in transformers that result in seemingly "mysterious" or "random" failures. A reliable way to avoid this is to measure DC current and adjust inverter drive to ensure balance. Edited March 4 by JIT Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 4 Share Posted March 4 1 hour ago, JIT said: In addition, inverter drive imbalance can cause remanence to build up in transformers that result in seemingly "mysterious" or "random" failures. Can you explain what you mean by "inverter drive imbalance"? Quote Link to comment Share on other sites More sharing options...
JIT Posted March 5 Share Posted March 5 (edited) 23 hours ago, Sid Genetry Solar said: Can you explain what you mean by "inverter drive imbalance"? The imbalance refers to drive characteristics that cause net magnetizing flux difference between the positive and negative halves of a mains cycle. Imbalance will cause remanence to build up. One cause of imbalance is asymmetry in the PWM drive and associated circuit elements (e.g. driver or FET propagation delay differences). External factors (e.g. load changes) can also trigger control responses that cause imbalance. One solution is to monitor flux and make appropriate drive control adjustments when the flux get too high but it's important to make adjustments that don't degrade the output power quality too much. Edited March 5 by JIT 1 Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 5 Share Posted March 5 5 hours ago, JIT said: The imbalance refers to drive characteristics that cause net magnetizing flux difference between the positive and negative halves of a mains cycle. So I can definitely see where this could very easily happen if the transformer primary was not being firmly driven push-pull style. (Most LF inverters, including the GS inverters utilize push-pull drive.) But with a push-pull style SPWM drive with bipolar modulation...the transformer doesn't have the chance to build up "net magnetizing flux difference". It's actually quite fascinating to put the FETs into a "single-ended" mode and let the transformer dance it's own wave around the SPWM signal from the FETs--in this type of scenario, yes, I would expect things to easily get out of hand and cause random failures. Quote Link to comment Share on other sites More sharing options...
Sid Genetry Solar Posted March 6 Share Posted March 6 One other observation I will make from my (unscientific) testing...I noticed that sometimes when turning the GS inverters off, I'd hear a little "snap" from inside. I traced it down to being the result of the inverter ending the sine wave "anywhere." Changing the code to always end the sine wave (except for serious faults) at the zero crossing solved the issue--now the GS inverters don't randomly "snap" due to the collapsing transformer magnetic field when turned off. 1 Quote Link to comment Share on other sites More sharing options...
JIT Posted March 6 Share Posted March 6 (edited) 18 hours ago, Sid Genetry Solar said: So I can definitely see where this could very easily happen if the transformer primary was not being firmly driven push-pull style. (Most LF inverters, including the GS inverters utilize push-pull drive.) But with a push-pull style SPWM drive with bipolar modulation...the transformer doesn't have the chance to build up "net magnetizing flux difference". It's actually quite fascinating to put the FETs into a "single-ended" mode and let the transformer dance it's own wave around the SPWM signal from the FETs--in this type of scenario, yes, I would expect things to easily get out of hand and cause random failures. It's possible with push-pull or full bridge PWM drive topology. Also, as mentioned, other external factors can cause it. Unless you are monitoring the flux you will never know sure if it's happening or not. Edited March 6 by JIT Quote Link to comment Share on other sites More sharing options...
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