TCCH Elcon 1.5kw charger schematics

Re: TCCH Elcon 1.5kw control board

Here is a sketch of the control board schematic drawn by paul (pdove) and mike (coulomb). There is a much larger version further down in the thread.

Coulomb's schematic index

Since I seem to be changing my versions of the schematics rather often, I thought I'd put an index here for easy reference. Many thanks to KennyBobby and PDove for the originals on which these are based.

AC Input - DC Boost Suipply (PFC stage).
High voltage DC output section.
The desaturation protection circuit.
Control board schematic as one page; as 4 pages (these have the latest updates).
Paul Dove's Eagle schematics.


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It could well be the bridge rectifier. I had one with burned 150R resistors and a bridge rectifier with a short AC to positive, I think.

You should also check for flashover from electrolytics to smaller capacitors. They sometimes use a cap larger than the board was designed for, and clearance can become way too small.

This information should prove useful, thank you!

I have a 1.5 Kw 48v ElCon with hdw ver 1.5 that has stopped recognizing the attached battery pack. Flooded LA 280 Ah, 48v. Red-Green 1 second constant flashing signal after the algorithm count signal.

Doing basic troubleshooting I found that the 48v lines made it into the charger. Opening the case ( so many screws ) I find that the 2w resistor in series with the diode across the output relay has burned open. Diode is OK.

I jumpered in a replacement resistor and powered up but no success. Started tracing the circuits using these schematics but with the black and yellow goop it is hard to locate components and reliably contact their leads.

The yellow goop is tenacious, any tips on removal?

Others who have had this problem, what was the root cause? Did you have success at repair?

TIA,
Bill

I'm not familiar with this charger, but I found the specs:
http://www.elconchargers.com/catalog/item/7344653/7638003.htm

It seems to have PFC so the PF is better than 98%. It also claims to have output short circuit protection, but I'm not sure how that is implemented. I don't understand the function of and reason for some of the circuit elements, and in general it seems way too complex for what it does.

It looks like the precharge relay does pull in when the 12V supply comes up. If that supply depends on the DC voltage for the raw output supply, then it would stay deenergized until that voltage rose to a nominal level, and would drop out eventually if the output were shorted while in operation or during start-up. A larger precharge resistance would probably also delay the rise of the 12V supply and extend the timing of the relay operation, but it really should be done by the processor or a simple analog circuit that senses the voltage across the relay (and resistors) and pulls it in only when it drops to a safe level. And the power supply should really be ahead of the precharge and rectifier/filter section, so that it powers the processor and other circuitry as soon as the unit is plugged in (or possibly controlled by a small switch).

It looks like the Viper 20A switching supply is configured differently from the recommended circuit:
http://www.st.com/web/en/resource/technical/document/datasheet/CD00070223.pdf

DC Output Section

PStechPaul said:

There is also something weird with the PNP transistor in the COMP circuit. It looks similar to the slope compensation or current limit connections, but they use NPN transistors. The three diodes in series (D12 and dual D9) also seems odd.

Click to expand...

Agreed with the oddities, including the snubber on the DC/DC. Perhaps for another day.

I'm going to post my updates to the DC output section, since I'm trying to sort out the snubber for the main MOSFETs. I think PDove was going to do a nice schematic in Eagle, but it may have stalled for time. KennyBobby, perhaps you would like to include this one in the post with the others near the start of this thread. I'd keep the original, in case I've stuffed up or inadvertently made something worse to read.

I'll also attach my desaturation protection partial schematic (see below for PDF version), since all schematics belong in this thread.

[ Edit: here is a partial list of updates: swapped Q1 and Q2, added 1R0 gate resistors, added capacitors C2, C46, C43, C15, and the 0.022uF, CB28 is not connected, asterisked many parts that vary with voltage and power options, and reworked the output relay contact part of the circuit. Added the MOV or whatever it is after the rectifiers D1/D4/D5/D6. Moved R29 to before the final common mode choke. ]

[ Edit Mar/01: Designators for C38, D17; value for C46 ]
[ Edit Mar/01 (2): fixed output relay contacts, shorted inductor. Thanks, PStechPaul! ]
[ Edit Mar/03: A few more designators (R2? -> R2, added L4, L9, large output inductor is definitely L(?) ). Added CB13 and CB20. ]
[ Edit Mar/04: C46 goes to ground, not to transformer B. ]
[ Edit Mar/09: Had Q1/R32/CB21 swapped with Q2/R31/CB18 (had swapped the wrong parts, making it worse than original) ]
[ Edit Mar/11: CB28 is indeed the connection from battery minus to DGND! ]
[ Edit Mar/11 (2): R25 and C43 are after the DC rectifiers (had them after the AC bridge rectifier). ]
[ Edit 2017/Apr/14: One of the C43s -> C34; values and designators for more capacitors. ]
[ Edit 2017/Sep/23: Corrected CB28; R22 range. ]
[ Edit 2017/Sep/24: R22 now 1-20 mΩ. ]

The snubber appears to be just RD (Resistor Diode) with no C (Capacitor), which is a bit unusual, but perhaps not unheard of. Perhaps C46 is part of the snubber arrangement, or perhaps it is attempting to make a resonant circuit, but I somehow doubt that.[ Edit: more likely it's to limit dV/dt, so the MOSFETs don't turn themselves on through Miller (drain to gate or reverse transfer) capacitance when switching off with high dV/dt. ]

The decoupling capacitors seem to be the 220 uF electrolytic C38, which would presumably be pretty useless at high frequencies, and C2, which is just a very small ceramic capacitor. That all seems a little light for suppressing ringing to me, but I'll be the first to admit I'm no expert in this area.

The charger I'm repairing at the moment, despite having tested it switching at 48 V and with 365 V on the DC bus (but not switching), ended up blowing one pair of MOSFETs immediately that it started charging for real. So I'm highly suspicious of the snubber circuit, at least on this charger. I'll test for ringing at 48 V on the DC bus once I replace the chain of parts that died (likely 2 x MOSFET, 1 x driver, possibly 1 x NOR gate, likely 2 x 1R0 gate resistor, will replace the diodes across the 10R gate resistors since they're very hard to test in place).

PStechPaul said:

The first common mode choke (L3?) seems to have the lower winding shorted. Also I don't see how the charging current connects to the output. The relay seems to just switch a capacitor from the green connector to one of two points in the circuit.

Click to expand...

My bad! Thanks for the pointers. Fixed now. KennyBobby, could you please copy the corrected schematic to the first page.

The diodes and low value resistors on one leg of the H-bridge seem to dump any high voltage transients back to the DC supply.

Click to expand...

Yes, where the massive 0.0022 uF capacitor absorbs them! Edit: But in fact, the resistors would be doing the absorbing. I can't see that the 0.0022 uF capacitor does anything, really. Even at 1 MHz the impedance is 72 ohms. [ Edit: I now believe that C38 absorbs all but the sharpest of the switching transients. ]

And I'm not sure of the purpose of the inductor on the low side of the output circuit.

Click to expand...

It's the big donut shaped one with the voltage and power rating for the whole charger is usually written on it. I think it's just the L part of an LC filter to get rid of the switching noise. It's equivalent to being in the positive side, where it would seem more natural. But the transformer output is floating, so it doesn't matter (except for capacitance to ground).

[ Edit: I now believe that it's essentially part of a buck converter. When the IGBTs are on, the charge current ramps up; when the MOSFETs are off, the battery current ramps down through the battery and the rectifier diodes (D1, D4-6). ]

Control Board Schematic

While I procrastinate over this charger (I can't find anything wrong with the capacitors), I thought I'd post my accumulated changes to the daughter board schematic. I had to save it at 75% size to get it under the 2.38 MB file size limit.

[ Edit: a big thanks to KennyBobby and PDove for the original schematic; despite the changes I made, the original was remarkably good; without it, fault finding on these chargers would not have been possible. ]

The main changes:
* Updates to the desaturation protection circuit, already published, but included for completeness.
* Added some designators, such as D4, D7, U12.
* Corrected some component values, mainly around U13 pin 5; R60 10R -> 100k; R73 3 kR -> 499 kR.
* Added some calculated voltages, mainly around U13 pin 5.
* Corrected some CON32S connections, e.g. 13 and 20 don't go to GND, but to the full bridge outputs.
* Added a few missing components, such as C58 (near Q7, upper left).
* Renamed 12VDC_Aux to 15VDC_Aux, reflecting the actual voltage better.
* Redrew several transistors as dual diodes.
* Made connections to the 7-pin round and 5-pin rectangular connectors more obvious.
* Added some text suggesting function, e.g. what the jumpers are for, when the comparator outputs are high, and so on.
* Added some missing connections, e.g. to the SYNC and VC pins of U14. Pin 13 of U13 connects to pin 12.
* Moved C50 from across R63 (U2 pin 13, near top left) to pin 19.
* Added a few test points, e.g. T44, T45, T33, T34.

Edit Mar/06:
* R107 goes to CON32S pin 5 now, for current sensing.
* Updated some resistor values: R107, R108, R110, R101.

Edit Mar/11: CB28 is indeed the connection from battery - to DGND! (Later changed to CB27.)

Edit Mar/18:
* Fixed R69, R75 go to source, not ground.
* Added part number for D5,D6 (also used in power supply)
* Tentative value for C40, C43: 3.3 nF

Edit Mar/28:
* Fixed PFC OVP threshold to 425 V

Edit 2017/Feb/23
* Added TP29; C38 and C46 definitely 100nF; D4, D7 LGE -> BR6.

Edit 2017/Sep/23
* CON32S pin 28 is a no-connect
* R23, R10 vary with voltage and/or power
* Added note re shunt across R10 via R20.

Edit 2018/Mar/13
* U2 powered by 15VDC_Aux (thanks, KennyBobby!)

Edit 2018/May/24
* Added R103, moved R98, C58; values for C56, C58.


Edit 2020/Jun/20
* See also the schematic on four pages, more up to date than the attached.