(100a / 13.8v) h_bridge "no" runing...

[NEWTOYBRAZIL]

Hello everybody, this is my first post in the forum.

I have used the much informations existent here in my littlest projects and circuits tests...

In this moment I have one "BOMB" in my hands! I assembled one (H_BRIDGE) to
control one motor in "13,8v" for a little electric car but, this circuit not work.

I'm probably doing it wrong ... During testing ... See the circuit used in the figure below ...

On the future this circuit will be drived with logic board based in one PIC microcontroller but in this moment I be testing with common switches...

I never used the IC "IR2110S", and do not know if this can be triggered only by reversing the levels in their inputs or pulses is necessary to make the engine run and reverse...!?

When I turn on the circuit, the voltage levels on the outputs of the drivers do not change.

And if I try to reverse the direction... The transistors begin to heat up ...

Have tested the transistors because I thought it could have killed them, however, nothing it's all ok.

Also replacing the two IC drivers however, nothing work ...

Someone has set up a circuit with this IC? Could give me some information?

I read this documents:
https://www.electro-tech-online.com/custompdfs/2013/08/ir2110.pdf
https://www.electro-tech-online.com/custompdfs/2013/08/an-978.pdf
But, no helped me so much ...

PEACE, HARMONY and HEALTH, from BRAZIL.

Thanks for any help and information.



This is a first prototype board...

; ;

 

[shortbus=]

Wow, where to start! There are many problems in your circuit.

1. You have what is called shoot through (a short circuit) in you H-bridge the way its drawn. The IR2110, should turn on the top mosfet on one side of the H-bridge and the lower mosfet on the other side. Not both both top and bottom on the same side. When both top and bottom of the same side are on it is a short circuit/shoot through/bad.

2. Why are the control signals to the IR2110 drivers connected to ground through resistors (R14 - 14 - 16 - 17 - 18)? This doesn't allow the control signals to function.

3. You have no flywheel diodes on the H-bridge/motor connections. Very important on inductive/motor loads.

To maybe help you, here is a good link on understanding H-bridges. His whole website may help you, take some time and read it. http://www.mcmanis.com/chuck/Robotics/tutorial/h-bridge/index.html

 

[ronsimpson]

Wow, where to start! There are many problems in your circuit.

I don't see whats wrong

1. You have what is called shoot through (a short circuit) in you H-bridge the way its drawn. The IR2110, should turn on the top mosfet on one side of the H-bridge and the lower mosfet on the other side. Not both both top and bottom on the same side. When both top and bottom of the same side are on it is a short circuit/shoot through/bad.

No shoot trough. The switch is a break before make and will solve that problem.

2. Why are the control signals to the IR2110 drivers connected to ground through resistors (R14 - 14 - 16 - 17 - 18)? This doesn't allow the control signals to function.

It functions just fine. When the switch is up one side on high and the other is low. When the switch is down the MOSFETs reverse. For that brief moment when the switch is in between the resistors turn off all MOSFETs. No shoot through.

3. You have no flywheel diodes on the H-bridge/motor connections. Very important on inductive/motor loads.

There are diodes in the MOSFETS. Maybe not the best but diodes. It looks like the switch will only be switch by hand so not very often. It it was switched 40000 times a second I could want good diodes, but by hand....we don't need good diodes.

edited------------------------
What is the voltage at:
CN5-1
CN5-2
CN5-3
CN5-4
CN5-5
CN5-6
CN5-7

 

[ronsimpson]

New idea. Three 30A relays. Why? If you connect CN5-4 to +5V the current will drop to zero. Same function as opening up the relays.

 

[johansen]

4 milliohms *100*100 = 40.

you're dumping 80 watts in this H bridge.

and, at 20 watts per T0-220, you're going to have an 80C difference in temperature between the heatsink and the die of the mosfet.
so the mosfet is running at 100-120C
which means instead of 4milliohms, you've got 5-6 milliohms.

so you're dumping 120 watts into the fet.
now the temperature difference is 100-120C between the fet and the heatsink.

its impossible to say for sure what the temperatures you're running it at are, without measuring the voltage drop through the H bridge
but i would recommend doubling the number of fets,
or buying lower resistance 30 volt fets

 

[ronsimpson]

so you're dumping 120 watts into the fet.

Where did you find out how much current is in the FETs? How much current is in the motor? Are you saying 100A?

 

[johansen]

heh, i assumed OP was complaining about the fets heating up because it was working..

if the fets are getting warm and the h bridge is connected to a supply that is capable of delivering 100 amps.. it probably would have blown up already.

in anycase, the fets aren't nessisarly under rated, but they need to be much better heatsinked.
4C/watt is apparently about the best you can do with electrically isolating thermal pads unless you want to use aluminum oxide wafers

 

[ronsimpson]

The heat sinks are huge. It may be because the gate to source voltage is not good. We really don't much. Maybe the current is too high. Maybe a FET is bad. We need much more information.

 

[Mr RB]

Huge? Interesting, I was going to suggest that he needed bigger sinks (or add fans) on a 100A motor driver.

I think Johansen made a good point about the I squared R losses too, that gets killer at 100A PWM and multiple output devices, FET specs, switching speeds etc all become critical.

 

[ronsimpson]

100A motor driver.

I missed it. Where did he say 100A? We don't know.

switching speeds etc all become critical.

It is switched by hand. There is a switch. I don't see a pwm. It only switches when you reverse direction.

Post#1 does not say much. Everything below that is just speculation.

 

[be80be]

LOL

(100a / 13.8v) h_bridge "no" runing...

It could be a 400 to 600 AMP if he wanted it to be the fet's say 390 using pwm for short burst's and about 110 each so thats 220 Big sinks and a fan is needed

 Repetitive rating; pulse width limited by
max. junction temperature. ( See fig. 11 )

 

[Mr RB]

Yeah I assumed that the switch would eventually be replaced with digital PWM control etc, it seemed a safe bet in one of those situations when we are guessing what the heck the O.P. is doing...

 

[ronsimpson]

I now know something:

1) The way the diagram is; one bottom FET should be on and the other must be off. He shows both bottom FETs have 0.002V gate to source. This can't happen.
A) CN5-4 might be wrong. It it was +5V then this could happen.
B) CN5-6 to CN5-3 and CN5-7 to CN5-2 might be wrong. If 6 to 2 and 7 to 3 this could happen.
C) The supply voltage is less than 10 volts.
D) Maybe FETs and drivers are damaged.
Please check 1A, 1B and 1C.

2)Design error: This works with a PWM but not with a switch. I should have seen this by post #3. Sorry!!
How the IR2110 works.
A) The bottom FET driver works very simple. Input is 0 or 5V and the output is 0 or 12V. Very simple. Power comes form pin 3. If this voltage is less than 10V it will not function.
B) The top FET driver is not simple. When working right the input is 0 or 5V and the output is 0 and 11 volts above the top FET's source.
Power does not come form the 13.8 supply directly. It comes from D1,2 WHEN THE BOTTOM MOSFET IS ON AND THE TOP MOSFET IS OFF. The output of the bridge must be at ground hard! Current flows through D1,2 and charges up C1,2. Then the top MOSFET is on and the bottom one is off, the bottom of C1,2 is up at 13.8 volts. The top of C1,2 is at 25V (about). The driver uses the power stored in C1,2 to work from. The driver uses 150uA and will in time discharge the capacitor and the top MOSFET will not get good gate drive and heat up. I think the driver should stop working at 10V across C1,2. BIG POINT: There must be switching (on/off at 10khz or higher) so that C1,2 have voltage stored in them. If a switch is used C1,2 can not charge up through D1,D2. The top MOSFETs can not be turned on for more than 10mS.

I should have seen that! I spent too much time saying 'there is a switch, no pwm' and did not think about what happens at D.C.

 

[jpanhalt]

100A continuous is still over stressing this design. The mosfet rating of 110A is a little deceptive. That is based on a calculation only using junction temp. You need to read the footnote to that rating (#5):



At best, you get 75A. But even that needs a good heatsink. Also, the IR datasheet I just looked at said 8 mOhm Rds(on), which goes up with junction temperature. At 100A and the max junction temp, you have more than 1 V drop (>100W). So, 100A per mosfet is way over driving it.

I suggest the OP stay to 50A or a little more per mosfet. In other words, two or three of these IRF3205 mosfets in parallel for each leg should work with a good heat sink.

John

Edit: In answer to your question about using the IR2110. I did a project in about 2000 using that driver and the LT1158 (https://www.electro-tech-online.com/custompdfs/2013/08/1158fb.pdf). Ended up using the LT1158. Both drivers are similar in principle. The LT1158 had feedback for both the top and bottom mosfet gates. It is the LT1158 that I used to drive 4 IR3205's in parallel. I was controlling a Ford heavy duty starter designed for 6V but operating at 12V. Current under load was probably 200A or more for <1 minute. Since you already have the IR2110 and not the LT1158, I would continue using what you have. I did not use the load sense function.

 

[NEWTOYBRAZIL]

Initially, thanks for your attention. Sorry for single diagram, but only got this by now ...
As nominal current or work current, this will be in the near average (30A), but in test the peak, reached 90A, believe me ... In normal running will be (30A)...

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After the first test, yes I am developing one board with PIC microcontroller for PWM control, lights control, sound control and more... In this moment I have test this power circuit...

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The motor used is this: **broken link removed**

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Well, the voltages on the concector "CN5" are:
1 = (+5v) logical, from microcontroller board " NOT EXISTENT NOW".
2 = (Hin 1) connected in (Lin 2) with wire-up for test...
3 = (Lin 1) connected in (Hin 2) with wire-up too...
4 = (SD1 and SD2) shoot down pin IC1 and IC2, put in gnd level for test...
5 = (GND) logical, from microcontroller board " NOT EXISTENT NOW".
6 = (Hin 2)...
7 = (Lin 2)...
8 = (OUT I -Sense) Future current sensor... NOT Implemented now.
9 = (ON/OFF) Return to activate 30A relays.
10 = (OUT +BAT) Used to connect switch ON / OFF to 30A relays...

This mode, I have connected the BATTERY (+ and -), ON/OFF power switch, (+5v and gnd) logical from bench power supply (test) and finally the HH switch for reversal test...

The pins Hin and Lin inversely connected , have your logical levels reversed acting in the test switch (H-H).

In this moment, the right side not respond with reverse of test switch (H-H).
But, the left side is OK... When the logic level on the inputs is changed, the outputs (Ho and Lo) is changed too.

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I don't put FAST DIODES under the IRFs transistors to reduce the size of board.

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The reason for the three relays is that the circuit under test already consumed (90A) """ peak """ ... And one commun switch would be too large ... With this argument, I use a small switch in (ON/OFF) circuit ...

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My programmer friend "Rubens" make programming the logic part ...
For me, is left to do all the physical "hardware" ...
The control board will provide logic control for H-Bridge and PWM... Respecting all timing necessary...
In this moment I need to know if it is possible to connect the circuit according to the scheme for testing rotating and reversing?
Just changing the logic levels at the inputs?
Or will I need pulsing signals in these entries?

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Again, thanks for your attention, sorry a little explanation for the circuit.
Receive all my respect and gratitude.

 

[ronsimpson]

30A that is good to know.

I think the IR2110 can not turn on the top MOSFETs for a long time. (>10mS) So the switch is a bad idea. There must be PWM for the top driver to work. See post #13.

For testing you can remove the motor and use a car light bulb. Use a head light for high current. Set the duty cycle for 50% and look at the results.

 

[NEWTOYBRAZIL]

You recommended to then change the logic levels at the bottom of the (H) bridge.
And the top of the bridge with the pulses (PWM)?!

 

[ronv]

You need a driver with a charge pump so they can stay on all the time.

Look at the HIP4060. Then you can either buy one or build a charge pump for the 2110.