Tronic's DIY dual Mosfet H-bridge (DSMhb)

Hi Rovor

You better use 1N5818 Schottky Barrier Rectifier Diodes with these motors.

BTW here is the part list for the Dual simple H-bridge 1.2b PCB:

Dual_h_bridge_parts.txt (0.89 KB)

And some preliminary version of it with photos:

dual_simple_hbridge_1_2b_parts.pdf (573.14 KB)

Regards, Thanos

Hi Thanos

Excellent job. This really does make it so much easier.

On behalf of the Sim community - Many thanks.

Re: Tronic's DIY dual Mosfet H-bridge

Hi Thanos,

Thanks for the partslist. I've checked the prices at my suplier and i it comes around the 50-60 euro's .

The RN-VN2 dualmotor (fertigmodel including postage) come's around the same price (bausatz-model is 10 euros cheaper).

Are there any advatages of your H-bridge on the RN-VN2. (except the fun of buidling it myself)

Thanks RoVoR

Re: Tronic's DIY dual Mosfet H-bridge

Hi Rovor,

Maybe your supplier isn't the cheapest around!!! I bought all these parts for the dual H-bridge only for 14euro here in Greece (not including the etched PCB)!!!

If you can't find a more cheap supplier then you can just order on-line the RN-VN2... But be aware that it can handle motor voltages only up to 16volt!!

My dual H-bridge can drive motors with voltages up to 50volt and around 25Amp safely (49Amp max)!!! And it you burn it, you can replace the mosfets cheaply.


Regards, Thanos

Re: Tronic's DIY dual Mosfet H-bridge

Hi Thanos,

I understand the advantages and i am planning to build your h-bridge.

WOW the prices at your suplier are very low, does he have a internetshop and sent to the netherlands , even with postage it wil be cheaper to buy there.

Has anyone builded the h-bridge yet and tested it or will i be the first one.

Thanx RoVoR

Re: Tronic's DIY dual Mosfet H-bridge

Hi Rovor,

I'm waiting the etched PCB for the dual h-bridge to arrive any day now from Germany...

Unfortunatelly my supplier doesn't have internetshop, its a small store after all! If all goes well with my tests I might consider sending you the materials... ;-)

Regards, Thanos

Re: Tronic's DIY dual Mosfet H-bridge

Hi,

Yesterday I received the PCB for the dual mosfet h-bridge. Here are some pics of it!







I had to drill little bigger the holes for the terminal connectors but otherwise it looks good! I hope I will solder it and test it soon.


Regards, Thanos

Re: Tronic's DIY dual Mosfet H-bridge

Hi Thanos,

I agree with RaceRay, it looks good.

I am interested to see how the contact between the terminal connector and the mosfets hold up, my gut feeling is the mosfets will need to be hard-wired to the board. The Gate is mighty sensitive. If the Mosfet goes high and smokes you'll be crashing into the barriers!

I'm including opto-isolators on my H-Bridge variant, to filter noise that may go into the Gate and also to isolate the logic supply from the motor power supply. If you want to have a look at the modified circuit let me know.

EvanF

Re: Tronic's DIY dual Mosfet H-bridge

Hi EvanF,

Good idea! Yes I'd like to see how you added opto-isolators on your desing! And why not, add it to the next version of the dual mosfet h-bridge as well!

It would be nice protection type for the control chip (74HC08), as well for the microcontroller to be more immune to noise comming from the motors!

I think the mosfets will hold well on the terminal connectors as you may crew them as hard as like solder the mosfets directly on the pcb. And on top of that, the terminal connectors I used, are rated 18amp at 120volt, that means they should hold for currents of 25amp at 12volt or 24volt...

Regards, Thanos

Re: Tronic's DIY dual Mosfet H-bridge

Hi Thanos,

Thanx man, Great offer, You've red my mind... :wink: . But only if it's not too much trouble.

Maybe it's an idea to make a combined order for the pcb and materials with all interested after the final version is completed. Maybe.....Just thinking, don't know if this can be realised.

Thanx again
RoVoR

Re: Tronic's DIY dual Mosfet H-bridge

@RoVoR
I mooted that suggestion a while back but the idea was cut down because it took away the challenge of sourcing parts! :sport:

Re: Tronic's DIY dual Mosfet H-bridge

Thanos developes a controller and H-bridge for us for free, and you are demanding him to collect even the parts for you? C'mon, I managed to find the parts quite easily, so you will find them too for sure^^
Imho Thanos has more important things to do, as to pack kits for you

regards

Re: Tronic's DIY dual Mosfet H-bridge

too easy

Re: Tronic's DIY dual Mosfet H-bridge

Don't know where you got your impression from. There were no demands and certainly not to Thanos. The idea/suggestion was a volunteer to gather all the bits. Perhaps someone who is good at finding parts online and has already done it easily!

Re: Tronic's DIY dual Mosfet H-bridge

Time Out ......Time Out.....

First off all i'm very gratefull for Thanos for developing the controler and H-bridge and everyone else around here for their support.

I was just putting my thoughts on paper. I share your opinion that Thanos can use his energy for more important things than packing kits, on the other hand maybe we should leave this decision to Thanos himself.

Anyway this is not the place to start a discussion about that so lets drop the idea and forget about it.

Regards RoVoR

Re: Tronic's DIY dual Mosfet H-bridge

Hi,

I think I've cleared my position before:

I clearly mentioned might consider!!!

Anyway I wouldn't want someone to construct anything I design before I test it!


Regards, Thanos

Re: Tronic's DIY dual Mosfet H-bridge

Hi to all,

I completed the first Dual Simple Mosfet H-bridge. I soldered the PCB and it passed the first tests succesfully.



For the first tests I used 6volt power supply and the 5volt test table motors. It produced proper motion using PWM on 24Khz same as RN-VN2 did. Slow and fast movements were executed as expected.

I didn't used any kind of cooling on the mosftets but no heating was developed on them during the tests. The motors was free run with no load but I think that even with load will handle amp rates of 5amp with no cooler plated attached on the mosfets. The fan should be mounted on it just in case...

I didn't dare to put it on the 12volt power and connect it with the wiper motors before attaching the cooler plates on the mosfets. Cutting these aluminium plates is somehow difficult in such small dimensions but it will be done.

Here is how you can mount it on the AVR motion controller and place a PC case fan on top of it:






I reinforced the thick power traces with lots of solder melted in them. I used one meter of solder on them to make them as thick is possible!! Now they can handle Amp rates of more than 30Amp!!!




During the tests I seen that the status leds were light only one at the time with no motor connected! But with motor connected both status leds were off, when brake was applied and both of them was turned ON during the start of acceleration of the motor. The led that was indicating the opposite direction of the motor was starting to fade only when a certain speed was developed. This lead me to conclude that the motor was backfiring (regeneration) the excess power to the h-bridge in low speeds or during acceleration, and luckily, was directed back to the battery thru the Schottky barrier rectifiers! That's why no overheating was seen on the mosftets!! Wow! Can't wait to see how it reacts on the wiper motors!

I took a video to see the reaction of the status leds during driving the small test table motor on 6volts power.

http://www.youtube.com/watch?v=S7UlG830_sc


I also made a short soldering guide to see the order of material placement to save some time during soldering it.

DSMhb_1_2b_solder_guide.pdf



If someone else has constructed and tested it by now, I'd like to hear his feedback on its performance.

Regards, Thanos

Re: Tronic's DIY dual Mosfet H-bridge

Thanks alot for the soldering guide, the pics and the vid!

Great work again! :gut:

regards
Christian

Re: Tronic's DIY dual Mosfet H-bridge

Hi,

Yesterday, I have cutted eight small aluminum stripes to use as heatsink on the mosfets. They are small cause I could not find larger pieces around the house but I think they are enough.




As you can see in the photos, I used just one bolt with a plastic distance holder, that holds the pieces pretty strong against the mosfets. Between the mosfets and the heatsink pieces I used polysynthetic silver thermal compound (particularly the Arctic Silver5) that is usually used in computer CPU coolers!






Haven't fire it up yet, with wiper motors, but it will be done the next days I suppose.

Regards, Thanos