High Power ESC Schematic

[ouew]

[ Specified attachment is not available ]Hi Guys,
First post here. I am making an ESC(Electronic Speed Controller) (trying to) and am looking for some extra eyes on my schematic before I start designing the pcb. The long end goal is a 13s 100A ESC, I am well aware of that making and testing fireworks is pretty dangerous, but I have not seen a lot of well documented designs at this voltage and I like a challenge.
I just want to clarify again that I know that this is going to be a pretty iterative and expensive process that will cost more than just buying an esc ready done.

First image is the design of the creator of the firmware AM32:
Second and third Image is the revised schematic that is hopefully readable:


[ Specified attachment is not available ]

[MarkF]

'ESC' - A small button in the upper left corner of the keyboard.  Right?

I wish members would spell out their acronyms the first time they use them.

Why must every topic posted turn into a research project just to determine what the subject is?
More and more lately, I find myself trying to guess what people are asking about.   

[rteodor]

'ESC' - A small button in the upper left corner of the keyboard.  Right?

I wish members would spell out their acronyms the first time they use them.

Why must every topic posted turn into a research project just to determine what the subject is?
More and more lately, I find myself trying to guess what people are asking about.   

ESC - electronic speed controller: a circuit typically used in RC (remote controlled) models to drive brushless tri-phase motors.
Fort the input they have supply voltage and one voltage to linearly control the RPM of the motor (by the kV constant expressed in V/RPM).
At the output they drive the motor coils and also sense the position by the same wires.

Hopefully I got all of that right.

[ouew]

'ESC' - A small button in the upper left corner of the keyboard.  Right?

I wish members would spell out their acronyms the first time they use them.

Why must every topic posted turn into a research project just to determine what the subject is?
More and more lately, I find myself trying to guess what people are asking about.   

I am sorry, if I knew that a post here would have to be at Uni(University) essay level I would of course have used a more proper way of writing. I did not expect them to be a rare piece of Electronic and I was hoping someone who already had some knowledge about powering BLDC(Brushless Direct Current) Motors could check if I had done something obviously wrong.

[rteodor]

'ESC' - A small button in the upper left corner of the keyboard.  Right?

I wish members would spell out their acronyms the first time they use them.

Why must every topic posted turn into a research project just to determine what the subject is?
More and more lately, I find myself trying to guess what people are asking about.   

I am sorry, if I knew that a post here would have to be at Uni(University) essay level I would of course have used a more proper way of writing. I did not expect them to be a rare piece of Electronic and I was hoping someone who already had some knowledge about powering BLDC(Brushless Direct Current) Motors could check if I had done something obviously wrong.

Oh, its not that. MarkF is working with models so I am a bit surprised that 'ESC' term escaped him. He is very knowleadgeable forum member otherwise (should you check his 3D printed models).
Anyway there are people here that can do a proper check on your schematic. Not me, I'm still trying to understand how the BEMF (back EMF) is read in your schematic. I still have many things to learn.

[ouew]

'ESC' - A small button in the upper left corner of the keyboard.  Right?

I wish members would spell out their acronyms the first time they use them.

Why must every topic posted turn into a research project just to determine what the subject is?
More and more lately, I find myself trying to guess what people are asking about.   

ESC - electronic speed controller: a circuit typically used in RC (remote controlled) models to drive brushless tri-phase motors.
Fort the input they have supply voltage and one voltage to linearly control the RPM of the motor (by the kV constant expressed in V/RPM).
At the output they drive the motor coils and also sense the position by the same wires.

Hopefully I got all of that right.

Yes, you got that correct. I would have wished for you to also specify what RPM(Revenue per Mille???) stands for . So the circuit is basically Moving an Electromagnetic field around in a circle, and this is a synchronous motor which means that the rotor(spinning part with permanent magnets) has to spin at the exact same speed as the magnetic field for this to work. it uses pauses between the phases to get a voltage reading to determine the RPM(Revolutions per minute) and position, this is called Bemf(Back emf(electromotive force)). the switching is done by a mosfet driver and a bootstrap capacitor which are controlled by a at32f421 running AM32 software. On top of that I also included a Capacitor bank, 48v to 5v buck converter circuit, a 5v to 3v ldo, and some debugging ports. I think overall that this could be a very good step forward for the whole RC community since upping the voltage means running components cooler for the same wattage, and since these don't cost much to produce it would be easy to sell and undercut the market so more people can get into the hobby.

[ouew]

'ESC' - A small button in the upper left corner of the keyboard.  Right?

I wish members would spell out their acronyms the first time they use them.

Why must every topic posted turn into a research project just to determine what the subject is?
More and more lately, I find myself trying to guess what people are asking about.   

I am sorry, if I knew that a post here would have to be at Uni(University) essay level I would of course have used a more proper way of writing. I did not expect them to be a rare piece of Electronic and I was hoping someone who already had some knowledge about powering BLDC(Brushless Direct Current) Motors could check if I had done something obviously wrong.

Oh, its not that. MarkF is working with models so I am a bit surprised that 'ESC' term escaped him. He is very knowleadgeable forum member otherwise (should you check his 3D printed models).
Anyway there are people here that can do a proper check on your schematic. Not me, I'm still trying to understand how the BEMF (back EMF) is read in your schematic. I still have many things to learn.

Hi, yeah I can see that he is a active member of this community and I do fully realise that his contributions since long have been part of what makes a community like this great, I was just I bit bummed about getting a comment about a ESC not being an obvious term in an electronic maker community. I made another comment under one of the replies specifying a bit more about my design, Bemf or Back emf is a way for a microcontroller to read the rpm through the voltage that the motor produces while spinning in between the activations of the coils.

[mtwieg]

Seems you've posted two completely different ESC schematics, one using AON6276 for the bridge and the other using PSMN1R4-40YLD. Which one do you want us to review...? Neither of them will will be able to handle 100A from a 13S battery (~48V).

[ouew]

Seems you've posted two completely different ESC schematics, one using AON6276 for the bridge and the other using PSMN1R4-40YLD. Which one do you want us to review...? Neither of them will will be able to handle 100A from a 13S battery (~48V).

Im sorry if it was unclear, the first one is my design(with the aon6276) and the second one is from the designer of the open source program as reference.
I was first under the impression that AON6276 80V 100A would be enough, but as im typing this out it's obvious that some headroom is required for the amperage at least. Thank you a lot, this is the exact thing I meant with a second pair of eyes looking over the design.

[Doctorandus_P]

How many times did you redraw all those boxes around trivially small schematic sections? And how much time did you spend on cramming everything together on a single page?

Combined with "connecting everything with labels" makes it difficult to read the schematic. How can anyone know if a net consists of 2 pins or 6 without resorting to KiCad's built in highlighting functions. (And those don't work on a PNG). The second schematic with whitespace to separate circuit sections is much more readable.

[mtwieg]

I was first under the impression that AON6276 80V 100A would be enough, but as im typing this out it's obvious that some headroom is required for the amperage at least. Thank you a lot, this is the exact thing I meant with a second pair of eyes looking over the design.

The 100A I_D rating for the AON6276 isn't a suggestion that the device can actually handle 100A in a real application. That rating assumes the device's case temperature is fixed (usually at 25C), which basically means you have an ideal heatsink (not happening in real life). The vast majority of FETs will have such a rating, as a way to compare one FET against another, but the actual current it will be able to handle in the application will always be much lower.

The I_DSM ratings are much more realistic, as it assumes a fixed ambient temperature, not a fixed case temperature. But even that is a crude approximation, the real current handling will depend a great deal on the PCB layout and how that PCB transfers heat to ambient.

And of course, even if ESC as a whole provides 100A, the average current through each FET will be less than that. And of course there's switching loss to consider too, which could be even greater than conduction loss, depending on your PWM frequency and choice of FETs....

If you know you're going to do many iterations, I wouldn't get too bogged down in thermal design just yet. You should focus on developing the signalling and control aspects, then scale up power later on. I think you will also need stronger gate drivers than the FD6288.

On the topic of signalling and control, it looks like you intend to sense backemf and battery current, as opposed to the reference design which senses backemf and motor current with a single shunt. The latter provides a current measurement which is useful for motor control, while your current sense circuit would only be useful for monitoring average current draw, not really useful for determining the motor current. I would not suggest replicating their current sensing method either, though. At high operating currents, a single shunt will lead to lots of issues with layout parasitics, ringing, etc. I would have separate shunts on each leg (at least two, if not all three), either on the source of the low side FETs or in series with the inverter outputs (requires current shunt amplifiers which can withstand a lot of common mode bounce, look up the INA240A devices from TI for example). IMO at high power levels having extra capabilities for sensing the motor state is worth it. You probably wouldn't regret adding interfaces for hall sensors or quadrature encoders as well (even if you don't intend to use them in the long run, they may prove invaluable while developing the control firmware).

[mtwieg]

How many times did you redraw all those boxes around trivially small schematic sections? And how much time did you spend on cramming everything together on a single page?

Combined with "connecting everything with labels" makes it difficult to read the schematic. How can anyone know if a net consists of 2 pins or 6 without resorting to KiCad's built in highlighting functions. (And those don't work on a PNG). The second schematic with whitespace to separate circuit sections is much more readable.

Okay on the topic of schematic aesthetics...
I also find the reference schematic to be much more readable overall (the way you group the bootstrapping diodes and caps with the FETs, away from the gate driver, is very messy IMO). Putting the BEMF sensing networks near the FETs might be an improvement, though. And I agree that cramming everything onto one page is not good.

But the absolutely unforgivable sin here is assigning multiple different labels to the same net (like PHASE_A and FD6288_VS1). That's a great way to make me give up on reviewing a schematic. The fact that KiCad even allows such a thing is baffling, to be honest.

[putcher1]

Hey i am designing ESC but i want an 40A ESC . It is my first time doind an ESC and i am struggling a little bit , i wanted to asked you how would i make sure to make my ESC handle the 40A should i foucus on the MOSFET bridge or the the Gate driver or what excatly.

[tooki]

(Attachment Link) Hi Guys,
First post here. I am making an ESC(Electronic Speed Controller) (trying to) and am looking for some extra eyes on my schematic before I start designing the pcb. The long end goal is a 13s 100A ESC, I am well aware of that making and testing fireworks is pretty dangerous, but I have not seen a lot of well documented designs at this voltage and I like a challenge.
I just want to clarify again that I know that this is going to be a pretty iterative and expensive process that will cost more than just buying an esc ready done.

First image is the design of the creator of the firmware AM32:
Second and third Image is the revised schematic that is hopefully readable:

Could you just remove the [attachimg] tags so the images revert to end-of-post attachments? They’re huge images (which is good for schematics!) but they force incessant back and forth scrolling since they’re displayed at 1:1 pixel scale within the message body with no good way to zoom out enough (without also making the text in the window tiny).