H-bridge controller with Mosfets, 100A, 100V for 2 DC brushed motors

Other Hardware Motors, Mechanics, Power and CNC
1

Hi, I was wondering if anyone knew of a resource or site that can tell you what size heat sink and/or cooling fan solution will be needed if the mosfet driver below is used near 100V and 100A (~10 kW)

I'm wondering if this can be used as an H-bridge to control 2 DC brushed motors,
i.e. 1 motor for forward/reverse, 1 motor for left/right on a lets say hobby level car.
or other applications where high current or voltage loads may be necessary.
i.e. like this EV car below.

From the little research I've done, I haven't really found a low cost solution
for driving brushless DC motors with low cost brushless drivers.
This is with respect to large loads for motors such as this:
https://bit.ly/30r3sKn
https://bit.ly/33qUGOz
Is there a way to drive these with Mosfets and the driver mentioned above without using the controls offered in the 2nd link? Some of the motors in the link above are running beyond 100A would it be just a matter of finding a Mosfet with a larger current rating i.e. on Digikey?

I've seen ESC drivers for quadcopter brushless motors and RC cars but are they controllable via an Arduino? Do I just send them PWM signals to run them?

2

The ESCs used for RC quads, cars and planes just need a servo signal to control them. Easily provided by an Arduino using the Servo.h library.

Other than that I'm afraid I have no idea what you're taking about because I don't follow anonymous links.

Steve

3

Thanks.

FYI...
The links below were too long so I shortened them on bitly.com
They are for brushless dc hub wheel motors on Aliexpress.
I think they can be retrofitted on to bicycles or a diy electric scooter.
The 8000W one is rated to run between 100-200A with voltages of 48V,60V, 72V.
The voltage will probably be dependent on the battery setup a person uses.
What I read on a website once was that once you go beyond 60V, it's considered beyond low voltage range classification so now I guess you're dealing with higher level voltages beyond 60V.

drazzy is on the forums and he sells some arduino boards and the mosfet driver on the tindie store.
I'm really curious to see if I can just passively cool it without a fan and just a heatsink if I ran a 72V DC motor near 100A (7.2 kW). The thing I'm unsure of is whether or not the 4 channel driver can be used as an H-bridge or if it is even an H-bridge module.

4

100A takes an array of MOSFETs with heatsinking. Even 1 milliohm at that current is 10W ignoring
switching losses (which probably dominate), and stall currents are a lot higher, so instantaneous
dissipation may creep up to the 100W mark.

Its a serious undertaking to make multi-kilowatt motor controllers, as failure mode is vaporization
of MOSFETs on a timescale of microseconds to milliseconds, so protection circuitry has to be
rock solid and fast acting.

5

So does this 4 channel driver below have protection circuitry?
Is it good enough for an Arduino to send PWM signals and controls the speed of 2 brushed DC motors that are rated lets say at 72V? (I haven't even considered starting torque current of the motor, or selected a specific one but just putting it out there for potential applications sake that others may use i.e. electric scooter or car)

4 channel mosfet driver 100A, 100V

What exactly does the protection circuitry consist of?

I just realized the link below is for a 8kW brushless hub wheel motor.
I've gotten mixed results based on my Google research of IGBTs and MOSFETs controlling brushless motors along with Hall effect sensors. Is this true?

The closest thing I could find for high voltage (600V), Tesla/EV level voltages was on digikey, but I wonder why the amperage levels are so low. This one is rated forr 400V max, 5A max (so only 2kW).
digikey bldc driver 400v max, 5a max, IGBT
I wonder why I can't find any with higher current ratings, are they nonexistent on the consumer level? A controls engineer once told me ideally you want higher voltages and lower amperages when it comes to power because current generates a lot of heat which in turn becomes waste. So it makes sense to me why all these EV manufacturers are going with high voltage on the motors. I just don't get why the controls or electronics are still expensive when you get in the higher kW range.

6

I built an H-bridge with 60A ,600V igbt-s, and the driver with 4 ,15V transformers to power and tlp251 optocouplers to drive the gates, they could be augmented with small transistors to make even stronger gate flip-flops, take care about filtration, overvoltage and overcurrent protections if you think of building. There are 1 chip variants from IRF too, should be enough for arduino spwm, under 70 dollars. researching for vfd code now.

7

@knightridar

DrAzzy is a regular contributor here on the forums you could reach out to him with a link to this topic that he may have missed.

Bob.

8

@Semtex9

I built an H-bridge with 60A ,600V igbt-s, and the driver with 4 ,15V transformers to power and tlp251 optocouplers to drive the gates, they could be augmented with small transistors to make even stronger gate flip-flops, take care about filtration, overvoltage and overcurrent protections if you think of building. There are 1 chip variants from IRF too, should be enough for arduino spwm, under 70 dollars. researching for vfd code now.

So that seems like you could power a 36 kW rated motor with that h-bridge.
Is there any book you would recommend regarding info for these things?
What is the purpose of 4, 15V transformers?
I'm guessing the optocouplers work similar to the way they work on relays?
Is IRF a brand of brushless drivers?
Any chance you can provide a link on digikey or something?
Thanks.

@ballscrewbob.
Thanks I PMed him to see if he can respond to the post.

Also this might be useful for the board DrAzzy provides on Tindie.
https://ihiconnectors.com/index.html

The board connectors on DrAzzy's board are rated only up to 40A.
The ones above have higher current ratings but may cost slightly more per unit and there are regular and SMT versions too.

9

To add to the last post,
I found some really nice MOSFETs but I wonder why they are so expensive.

On the Digikey website the largest power dissipation single MOSFETs I could find were rated for 5kW,
ROHS compliant and an active part (so still being sold and made regularly).

They have 5 left after filtering it out for 5kW.
They are all in the $300 range.

The voltage choices are 500V, 1000V, 1200V (Drain to Source Voltage (Vdss)
and
current choices 171A, 215A, 497A (Current - Continuous Drain (Id) @ 25°C)
They are all offered from Microchip.
Digikey MOSFETs filtered ouT 5kW, 500-1200V range, 171-497A range, ROHS active parts

When I went to the array section I found this beast, but it's $3k+!!!!
Digikey MOSFET, 1200V, 1015A

10

knightridar:
So does this 4 channel driver below have protection circuitry?
Is it good enough for an Arduino to send PWM signals and controls the speed of 2 brushed DC motors that are rated lets say at 72V? (I haven't even considered starting torque current of the motor, or selected a specific one but just putting it out there for potential applications sake that others may use i.e. electric scooter or car)

4 channel mosfet driver 100A, 100V

It has gate drivers if you select that option, but it won't handle 100A at all - its a pcb, pcb traces
vaporize at those current levels!!! 100A will involve thick bars of copper everywhere, something like
15 mm^2 cross-sectional area of copper is good for 100A.

What exactly does the protection circuitry consist of?

Components that detect when the device's parameters could be exceeded and immediately
turn off the FETs (within microseconds). Over current being the most important situation.
You also arrange for enough dead-time to prevent shoot-through, detect under-voltage on
the gate drivers (which might allow the devices to become half-turned-on and immediately
destroy them).

At 100A you'll need multiple paralleled MOSFETs, or extremely bulky stud-terminal devices
like this: https://uk.rs-online.com/web/p/mosfets/1684576/

I just realized the link below is for a 8kW brushless hub wheel motor.
I've gotten mixed results based on my Google research of IGBTs and MOSFETs controlling brushless motors along with Hall effect sensors. Is this true?

The closest thing I could find for high voltage (600V), Tesla/EV level voltages was on digikey, but I wonder why the amperage levels are so low. This one is rated forr 400V max, 5A max (so only 2kW).
digikey bldc driver 400v max, 5a max, IGBT
I wonder why I can't find any with higher current ratings, are they nonexistent on the consumer level?

RC ESC's are the cheapest high-current motor drivers out there, some will handle this sort of current,
but the construction isn't the most rugged (I've seen ESCs erupt in flames several times...)

A controls engineer once told me ideally you want higher voltages and lower amperages when it comes to power because current generates a lot of heat which in turn becomes waste. So it makes sense to me why all these EV manufacturers are going with high voltage on the motors. I just don't get why the controls or electronics are still expensive when you get in the higher kW range.

Its very simple, there's enough power available to vaporize the semiconductors in microseconds should any kind of overload occur - so you can't get away with lack-lustre circuits, they have to be rock solid at
preventing devices being taken beyond their ratings, even for a microsecond.

100A is 10 thousand times more energetic than 1A, since power dissipates as I-squared-R. Even if you
manage to scale down all the resistances by a factor of 100, its still 100 times more tricky than 1A...

With high currents being switched induced voltages due to magnetic fields get large, you cannot ignore
them, they can be enough to destroy a MOSFET's gate-oxide layer when high currents are switched
fast just because of the lead inductance on the source of the MOSFET... This means layout gets more
critical, and you have to address control of the switching speed (too slow and the dissipation becomes
excessive, too fast and the induced voltages can't be tamed).

With high voltages being switched induced currents due to stray capacitance get large, so you have to
ensure the gate electrode is driven from a low impedance source that can soak away these currents.

Basically as power levels increase everything gets more critical, and you have to run close to device
limits anyway to keep costs reasonable (protection electronics is cheaper than power devices).

11

Thanks for the detailed responses.
It would be nice if there was a book out there specifically for electric motor drivers/controls.

It has gate drivers if you select that option, but it won't handle 100A at all - its a pcb, pcb traces
vaporize at those current levels!!! 100A will involve thick bars of copper everywhere, something like
15 mm^2 cross-sectional area of copper is good for 100A.

Is the 2 oz copper not good enough then on the board?
So basically I just have to create a straight wire connection to the MOSFET?
I just used the Wikilink below for wire gauge charts, and used a little safety factor to determine wire size.
Gauge 00 wire or 9.266 mm diameter wire is rated for 145A @60 degrees Celsius.

Components that detect when the device's parameters could be exceeded and immediately
turn off the FETs (within microseconds). Over current being the most important situation.
You also arrange for enough dead-time to prevent shoot-through, detect under-voltage on
the gate drivers (which might allow the devices to become half-turned-on and immediately
destroy them).

Shoot through explained
I tried to google something regarding under-voltage on the gate drivers. Not sure what this means.
Will I have issues if I power a lower voltage motor i.e. 6V,12V, or 24V with these drivers?
I'm not sure how having a lower voltage will destroy the gate drivers.

RC ESC's are the cheapest high-current motor drivers out there, some will handle this sort of current,
but the construction isn't the most rugged (I've seen ESCs erupt in flames several times...)

I've seen a bunch out there, especially on Aliexpress. Was curious as to how long they can sustain current loads. Not sure if there is a big difference between the RC car ones versus the quadcopter ones.
150A, 3-6S
300A, 12S
Just a few examples that I hope would not burn up.

Its very simple, there's enough power available to vaporize the semiconductors in microseconds should any kind of overload occur - so you can't get away with lack-lustre circuits, they have to be rock solid at
preventing devices being taken beyond their ratings, even for a microsecond.

100A is 10 thousand times more energetic than 1A, since power dissipates as I-squared-R. Even if you
manage to scale down all the resistances by a factor of 100, its still 100 times more tricky than 1A...

With high currents being switched induced voltages due to magnetic fields get large, you cannot ignore
them, they can be enough to destroy a MOSFET's gate-oxide layer when high currents are switched
fast just because of the lead inductance on the source of the MOSFET... This means layout gets more
critical, and you have to address control of the switching speed (too slow and the dissipation becomes
excessive, too fast and the induced voltages can't be tamed).

With high voltages being switched induced currents due to stray capacitance get large, so you have to
ensure the gate electrode is driven from a low impedance source that can soak away these currents.

Basically as power levels increase everything gets more critical, and you have to run close to device
limits anyway to keep costs reasonable (protection electronics is cheaper than power devices).

I've read a little bit about IGBTs. In higher power applications are these the better choice then vs a MOSFET? I know they are used a lot in VFD drives.
Would these be a better choice for EV car motors?

12

All electric cars seem to use IGBTs, not MOSFETs. Its the natural choice for high voltage. With
low voltage they are too inefficient to be useful (less than 200V for instance) - low voltage high
power is for MOSFETs.

But at high voltage IGBTs are more robust than MOSFETs, as the gate is better protected from the
drain/collector and they naturally scale to high voltage. Its incredibly easy to blow MOSFETs at
100's of volts that no-one really wants to risk designing with them when IGBTs are available
(the 'standard' IGBT breakdown voltages are 600V and 1.2kV)

Newer devices are coming along based on wide bandgap semiconductors, so this will all change soon
with GaN and SiC devices coming to the fore, some of these are HEMT style MOSFETs which are
different yet again. There's a small chance too that diamond-based semiconductors will become
practical too, perhaps the ultimate wide-bandgap semiconductor, being a way better thermal conductor
than any other material at room temperature.

But you always need good protection circuitry for high power, or you have something that works one
day and vaporizes the next...

13

All electric cars seem to use IGBTs, not MOSFETs. Its the natural choice for high voltage. With
low voltage they are too inefficient to be useful (less than 200V for instance) - low voltage high
power is for MOSFETs.

Interesting. I wonder where the 200V number comes from?

I'm going off on a bit of a tangent but it would help me decide if an
H-bridge with MOSFET's is a better choice or
some type of Brushless DC motor driver or
some type of 3 phase and/or 1/single phase AC motor driver etc
for the application below.

So here is a hypothetical real life scenario.
Let's say whether we are in the US /Japan (120V) or rest of the world (240V).
Let's say a family consumes 1550 kWh of electricity in a month (simplify to 31 days) --> 50 kWh/day.
I was reading up on wind turbines and the impression I got is the generators are AC induction motors.

Now in industry I've heard/read about VFD (Variable frequency drives) that typically use IGBTs to power 3 phase AC induction motors.
However, let's say we had a wind turbine for the home.
Is a brushless DC motor or AC induction motor a more efficient choice to use an a generator?
Assuming we have wind for 12 out of 24 hrs a day we'd need to generate ~4.2 kW/h to get 50 kWh/day.
So for
120V --> .035 kAh
240V --> 0.175 kAh

  1. Isn't it more efficient to have a generator/motor that runs closer to your home voltage (120V/240V) to avoid losses in efficiency?

I'm guessing/assuming just like a solar panel setup an MPPT setup may be useful for varying loads on the wind turbine, but running it near those voltages would be ideal?

  1. Would it be more efficient to use MOSFET's or IGBT's in this scenario (120V and/or 240V) gather power from the motor/generator?

I'm unfamiliar with the inner workings of a grid tie inverter, so would these even be the components that would be used to bring power into the home?

  1. Since most homes in the US (not sure about the rest of the world) are wired for only single phase, would it be more efficient to use a 3 phase motor or 1/single phase motor for power conversion on the wind mill?
14

Well I just found these:

Maybe I'm wrong but these look like they have high power usage potential.

15

knightridar:
Interesting. I wonder where the 200V number comes from?

IGBT typically has 1.8V forward voltage, so at 10A dissipates 18W.

200V MOSFET typically has 100 milliohms on-resistance or so, so dissipates 10W at 10A,

so this is the kind of voltage where conduction losses are roughly comparable.

At higher voltage MOSFET losses increase as the on-resistance increases with voltage rating,
at lower voltages IGBT losses increase (as a fraction of total switched power, since the forward
voltage is fixed).

As voltages increase the fast switching of a MOSFET has to be deliberately slowed down to
limit the dV/dt value, since if that's too high the device can destroy itself though internal
capacitive coupling between drain and gate - IGBTs are less sensitive to this and switch
slower in the first place - hence the robustness. Basically IGBT has one more layer of doped
semiconductor between the output terminal and gate, which helps protect the gate.

16

knightridar:
@Semtex9
So that seems like you could power a 36 kW rated motor with that h-bridge.
Is there any book you would recommend regarding info for these things?
What is the purpose of 4, 15V transformers?
I'm guessing the optocouplers work similar to the way they work on relays?
Is IRF a brand of brushless drivers?
Any chance you can provide a link on digikey or something?
Thanks.

@ballscrewbob.
Thanks I PMed him to see if he can respond to the post.

Also this might be useful for the board DrAzzy provides on Tindie.
Welcome, IHI Connectors & mechanical wire & cable lugs
Single Wire Lugs, 1 Wire Termination per Lug
American wire gauge - Wikipedia

The board connectors on DrAzzy's board are rated only up to 40A.
The ones above have higher current ratings but may cost slightly more per unit and there are regular and SMT versions too.
https://www.tindie.com/products/drazzy/4-channel-logic-level-mosfet-driver-100a-up-to100v/

Ok sry for not responding, 4 transformers galvanic insulate the gate drivers from one another, since high and low emitters get to different voltages, and you need 15 V between gate and emitter(igbt).
If you tried to fire a pair with one grounded psu, you would ground high emitter together with a low one, and get a very nasty short between high emitter that gets to the DC rail 100V when it fires, and low emitter that is DC rail ground. 2 of my gate driver psu grounds float to the high emitter voltage while other two are grounded with DC rail ground, all are separated, its not ideal, but it works fine.

I have no pictures yet because I am still working on it.

I wouldn't go above half the rated power, fused it at 25A, but theoretically yes its beefy.

IR is International Rectifier, brand for IC, like Fairchild or toshiba, sorry, take a look at this one IR2136, and search for International rectifier application notes for that IC, to get an idea on different driver designs.

2 more problems are that gates require higher energy on higher duty cycle frequency, and that if you select a wrong gate resistor or long gate lead, the capacitive gate can resonate with inductive lead, and turn the igbt on and off repeatedly for 1 pulse if it charges too fast ie resistor too small, or if it charges too slow ie too big a resistor, it will heat fast, and that can also destroy your stuff. With mosfets or igbt it is crucial that you ground the gate when you want it to turn off fast, that's why i use tlp251 flip-flops, and if you set a diode antiparalel to gate charge resistor, you can go even faster.

Another fact is that you will need to design some good protections so that if things go wrong your circuit dosen't explode. "kassakian: principles of power electronics" is a good read, also "Inaustrial Power Engineering and Applications Handbook by K.C.Agrawall". Higher the power rating more prediction needed. Account for overvoltage, overcurrent, missfire, RF interference due to very high currents being pulsed, reactive load transients, and anything else that you can think of. If that thing explodes, you can get seriously hurt, or start a fire. Protect yourself while testing, and be SURE any HV capacitors are empty when you touch the rail, they will take your hand off.

You might need to account for inrush current when you plug that thing in, depending on design because you might need a lot of capacitors, to stabilize the DC rail. One way to limit inrush is with ptc or ntc thermistor, bypassed with a relay when the capacitors charge up. If you are using batteries to get 100V those have their own set of dangers to prepare for, and design protections.

Arduino uno can barely drive it in my case because i got an lcd, and pid, and a keyboard, and it uses only two channels so i can't achieve full controll by all quadrants, but I drive a welder, you would need to be able to control igbt-s individually so you can brake, or set the motor in idle. I can send you the spwm code with variable amplitude and frequency that I found, but you will need to work on it some more for full control.

Oh, and optocouplers are used kind of like fast solid state relays because I have 4 different grounds/commons. 1 is main dc rail, together with two of the gate drives are also on it, other 2 commons are for 2 high emitters, and their gate drivers, 4 is the arduino ground that is powered independently, so that arduino is nowhere near the power output side. Optos are also good protection for your control logic, since they can insulate 5000V, while transmitting the signal, only down side is a small delay because they are not nearly as fast as cmos, but its ok up to a couple of mhz, and you will aim way lower than that for your duty cycle.

100V 100A is no joke, you will need to get very serious if you want to do it, or purchase professional igbts with drivers already on them, but those cost a ton, and you might fry them. I recommend you build a smaller scale system for testing first.

17

Anyone trying to read that solid BLOCK of text is going to get confused.
Maybe you should edit it to reflect paragraphs and lines etc.

I gave up at the third line ! :fearful:

18

ballscrewbob:
Anyone trying to read that solid BLOCK of text is going to get confused.
Maybe you should edit it to reflect paragraphs and lines etc.

I gave up at the third line ! :fearful:

yup thx