Author Topic: Design and build a 50V 300A BLDC motor control  (Read 5608 times)

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Offline canicollTopic starter

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Design and build a 50V 300A BLDC motor control
« on: May 27, 2018, 07:59:09 am »
Hello all,
I am new here and to electronics so I probably wont easily understand your advice but I am willing to learn and research each step of my BLDC esc journey.
My project is to design and build a sensorless BLDC motor controller which is capable of running 1 (and later possibly 2) 50V 300A motor using an analogue input such as a 2 position micro switch or a potentiometer.
I have nothing resembling the required knowledge to complete this project which is why I am joining your forum in the hope that some of you might be willing to help me complete my task but I have just bought an Arduino kit to learn some programming.
I'll begin by searching old posts and learning as much as I can from previous discussions.

I hope I've posted this in the correct category and thanks for reading. I look forward to any advice you have on where I should start.

Cheers,
Cameron
 

Offline abraxa

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Re: Design and build a 50V 300A BLDC motor control
« Reply #1 on: May 27, 2018, 09:16:24 am »
For somone who possesses "nothing resembling the required knowledge to complete this project ", this is a *huge* undertaking with a lot of brain wrecking involved. Do you have a time frame for this project? While I don't mean to sound discouraging, I strongly suggest you tell us why you want to take on this project in the first place because it could be very frustrating to you and outright dangerous as well.
 

Offline max_torque

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Re: Design and build a 50V 300A BLDC motor control
« Reply #2 on: May 27, 2018, 10:53:29 am »
Get yourself over to endless-sphere.com, and check out the "Motor Technology" forum. A mine of useful info, and a record of just how hard it is to do what you want to do with zero experience!

 
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Offline canicollTopic starter

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Re: Design and build a 50V 300A BLDC motor control
« Reply #3 on: May 27, 2018, 10:55:48 am »
Hi abraxa, thank you for the reply.
I don't have a time frame and I understand the complexity of this project which is why I am asking for guidance in this forum.
I bought a BLDC motor with the idea of learning electronics through practical application and at this stage I don't have an application for it but i'm sure I will think of something to put it in.
Another reason is that I think this thread could possibly turn into resource for many other people who wish to design a basic circuit to control a BLDC motor. By basic, I mean without a reverse feature, soft start or regen braking. There are so many applications for BLDC motors these days and off the shelf controllers are very expensive. I believe many will benefit from this.
I do like to bite off more than I can chew but anything is possible if you take small bites and are willing to chew. I am familiar with electrical danger as I install high voltage solar systems on commercial buildings.

Thank you again for your input and hopefully we can build an informative and popular thread.  :-+

Regards,
Cameron
 

Offline canicollTopic starter

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Re: Design and build a 50V 300A BLDC motor control
« Reply #4 on: May 27, 2018, 10:57:06 am »
Thank you for the link Max, I'll go and have a read. :-+
 

Online Siwastaja

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Re: Design and build a 50V 300A BLDC motor control
« Reply #5 on: May 27, 2018, 05:20:55 pm »
Start with a 30A, or even just a 10A motor first. The 50V,300A inverter is difficult even for many seasoned experts.
 
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Offline Simon

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Re: Design and build a 50V 300A BLDC motor control
« Reply #6 on: May 27, 2018, 06:41:11 pm »
Thank you for the link Max, I'll go and have a read. :-+

Not sure what you want to be doing with an arduino. you want something more powerful with more efficient libraries than that muck. I know every man and his dog use them and channels like great scott use them to death but a 300A BLDC is no mean feat. 15KW is a mere 1/3 of what you need for an electric car. My only use of arduino's is for one off test jig's at work where it just needs making fast and there will only be one and the code does not need to be fast.
 

Offline canicollTopic starter

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Re: Design and build a 50V 300A BLDC motor control
« Reply #7 on: May 27, 2018, 07:40:17 pm »
Thanks for your input Siwastaja.

Simon, thank you. Yes I did get the Arduino because there are many resources online to learn from and I figured I have to start somewhere.
The way I see it, this project can be split into two parts. One being circuit design and 2, coding. Would that be a correct assumption?

Would the circuit design remain the same regardless of microcontroller? What MC would you recommend? I found the ST7 but it's prohibitively expensive.
 

Offline Simon

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Re: Design and build a 50V 300A BLDC motor control
« Reply #8 on: May 27, 2018, 07:51:49 pm »
Simon, thank you. Yes I did get the Arduino because there are many resources online to learn from and I figured I have to start somewhere.
The way I see it, this project can be split into two parts. One being circuit design and 2, coding. Would that be a correct assumption?

Would the circuit design remain the same regardless of microcontroller? What MC would you recommend? I found the ST7 but it's prohibitively expensive.

NO! before circuit design comes the fundamental understanding of the physics and the technology. I would never pretend to know about this. Max Torque is your man for that if you had more time than I know he has to put you through the equivalent of a crash uni course.

I don't know which is the best µC, last I heard ST do a µC that has libraries written to control motors. I work with motor drivers that go up to 2KW using 8 bit PIC's but I have no idea what else is inside of them.

This is a whole field and minefield of it's own, electronics is but the start.
 

Online BravoV

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Re: Design and build a 50V 300A BLDC motor control
« Reply #9 on: May 27, 2018, 07:58:25 pm »
I found the ST7 but it's prohibitively expensive.

If ST7 microcontroller is "prohibitively" expensive for you, assuming you don't make mistake on the 1st power up on this motrol control and just work flawlessly for the 1st time  ::), all the needed parts excluding the MCU for building that 50V 300A thingies probably way over your budget.

Did I miss it ? You still don't provide your budget. $50 ? $100? $500? ... etc
« Last Edit: May 27, 2018, 08:09:49 pm by BravoV »
 

Offline Simon

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Re: Design and build a 50V 300A BLDC motor control
« Reply #10 on: May 27, 2018, 08:03:23 pm »
Yes, your processor cost is the least of your concern just wait until you do the power electronics and then need some weird and expensive chips or something. This is a 15KW device, stuff costs what it costs.
 

Offline TopLoser

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Re: Design and build a 50V 300A BLDC motor control
« Reply #11 on: May 27, 2018, 08:17:50 pm »
I’ve got one of these really cheap, good starting point to get something working maybe?

http://uk.farnell.com/stmicroelectronics/stm8-128-mckit/starter-kit-motor-control/dp/2318884
 

Offline Simon

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Re: Design and build a 50V 300A BLDC motor control
« Reply #12 on: May 27, 2018, 08:21:12 pm »
One word of warning with ST..... They are well behind schedules with lead times in the 6 months and rising
 

Offline Simon

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Re: Design and build a 50V 300A BLDC motor control
« Reply #13 on: May 27, 2018, 08:23:01 pm »
I think PSOC is the easiest to set up as their IDE has a graphical programming interface but nothing comes free and they may be expensive chip's. I have a dev board for a low end ARM but have not got round to doing anything yet.
 

Offline NiHaoMike

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Re: Design and build a 50V 300A BLDC motor control
« Reply #14 on: May 27, 2018, 08:45:15 pm »
That voltage sounds like some requirement to stay under the low voltage safety limit.
Cryptocurrency has taught me to love math and at the same time be baffled by it.

Cryptocurrency lesson 0: Altcoins and Bitcoin are not the same thing.
 

Online Mechatrommer

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Re: Design and build a 50V 300A BLDC motor control
« Reply #15 on: May 27, 2018, 08:58:09 pm »
I hope I've posted this in the correct category and thanks for reading. I look forward to any advice you have on where I should start.
if you cant afford this... https://www.ebay.com.my/itm/300A-ESC-For-Brushless-Motor-3-16S-LiPo-Airplane-Plane-Helicopter-300-AMP-OPTO/222094792152?hash=item33b5e195d8:g:l1AAAOSw-QBXPfn9 then maybe you may start here... https://simple-circuit.com/arduino-sensorless-bldc-motor-controller-esc/ but at 300A? you may need 3 or more fet pair for each winding... as a beginning may i suggest start with designing low amp ESC first? in the range of 10-30A? and then later moving up to your required current... fwiw..
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Online BravoV

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Re: Design and build a 50V 300A BLDC motor control
« Reply #16 on: May 27, 2018, 08:58:33 pm »
I look forward to any advice you have on where I should start.

One of my favorite at other thread on the OP's persistence and effort in building his motor controller, not a popular thread though, but its in my bookmark as I follow it closely.  :-+

Try read -> BLDC Motor Controller, Design, Waveforms, Thermal Tests

At least this will give you the clue on the work involved, also the tools and finally the knowledge & skill needed. And watch and take note on his journey , and question yourself if you're ready for this kind of work ahead ?

Hope this helps.

Offline canicollTopic starter

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Re: Design and build a 50V 300A BLDC motor control
« Reply #17 on: May 28, 2018, 09:50:42 am »
So I've finished work and ready to read your advice and OH MY GOD
I certainly didn't expect this level of difficulty. While I have the ambition and drive to undertake this, I honestly could not expect any of you to try and teach me this. I think that would be quite selfish of me and there seem to be cheaper and faster ways to get me to where I need to be.

I'm thinking a $300 R/C esc is looking quite attractive now.
Would it be possible to build an analog to digital converter to replicate the signal from a radio control receiver and if so, would that be something a noob like me could undertake?

Thank you all so much for your replies and words of wisdom. It's nice to come to a forum where people are as generous with their will to help as you all are.

Cheers,
Cameron
 

Online Mechatrommer

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Re: Design and build a 50V 300A BLDC motor control
« Reply #18 on: May 28, 2018, 11:02:55 am »
I'm thinking a $300 R/C esc is looking quite attractive now.
Would it be possible to build an analog to digital converter to replicate the signal from a radio control receiver and if so, would that be something a noob like me could undertake?
R/C ESC usually takes 20Hz 5V PWM signal iirc. there are few ways to emulate this. one way is using pic or avr tiny to read analog pot voltage in one input pin and output corresponding PWM on another pin, another way is using 555, whichever suits you... http://www.instructables.com/id/Yet-Another-Simple-Pot-controlled-555-PWM-generato/
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 
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Offline max_torque

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Re: Design and build a 50V 300A BLDC motor control
« Reply #19 on: May 28, 2018, 11:07:07 am »
Generally speaking, off-the-shelf inverters are expensive for two reasons:

1) Power silicon, film capacitors, current sensors etc, costs money, quite a bit of money.  the BOM for a kW level inverter can easily be in the $100's, especially in low volumes

2) Developing the hard and software for such an inverter takes time and effort. At low sales volumes, re-couping that investment is not easy!


Whilst there are several off-the-shelf BLDC software control packages from various manufacturers (ST, NXP etc) the problem with starting with one of these is you have no idea about the theories or basics, so when something (inevitably) goes wrong, you are often left with a smouldering pile of silicon and absolutely no idea what went wrong.

And whilst a $300 inverter might seem expensive, that's less than the cost of the oscilliscope you will need to buy to get your own version to work!  (and let alone the soldering tools, power supplies, S/W toolchains etc etc)


If you want to learn about controlling motors, from a theory perspective, then an arduino and a basic H bridge (plenty to choose from on ebay) is actually a really good way of getting a small motor to spin on the bench. You'll learn a lot, and your 'failures' won't be too costly.

 
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Offline canicollTopic starter

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Re: Design and build a 50V 300A BLDC motor control
« Reply #20 on: May 28, 2018, 11:22:59 am »
Tks guys, Max you make great points here. I have the Arduino and I'm sure I have some IRF3205s laying about that I use to repair solar charge controllers so I will definitely start on that so I can get a better understanding of what's going on. That is after all why I'm doing this.
I find it amazing how cheap these RC ESCs are now considering the facts you've put forward. Nothing like volume to bring costs down I guess.

Mechatrommer, Thank you for that link. I didn't know a 555 could be used that way, I honestly thought it was just a digital counter.
 

Offline Simon

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Re: Design and build a 50V 300A BLDC motor control
« Reply #21 on: May 28, 2018, 11:28:50 am »
I've had the motor in a radio control helicopter go up in flames and smoke (literally) for no reason and that was just an out of the box commercial item.

If you are looking at arduino and have never programmed before then it's a start but hopefully you outgrow it and then you have a whole range of controllers to choose from. I am sure there is an AVR with 3 timers and an app note on how to generate the 3 phases of a motor controller.
 

Offline Simon

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Re: Design and build a 50V 300A BLDC motor control
« Reply #22 on: May 28, 2018, 11:33:29 am »
You can easily program a µC to read an analogue signal and generate PCM at 50Hz (not 20Hz but 20ms period) you will want a 16 bit counter as with RC PCM you run a minimum of 1ms and the go up to 2ms so really only use 10% of the PWM range. (not so arduino friendly)
« Last Edit: May 28, 2018, 11:50:18 am by Simon »
 

Offline canicollTopic starter

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Re: Design and build a 50V 300A BLDC motor control
« Reply #23 on: May 28, 2018, 11:44:39 am »
Yes Simon, there is an AVR with 3 timers and I also found the AN for sensorless BLDC control.
It is here if anyone is looking http://www.microchip.com//wwwAppNotes/AppNotes.aspx?appnote=en591508
Thanks for tip.
 

Offline Simon

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Re: Design and build a 50V 300A BLDC motor control
« Reply #24 on: May 28, 2018, 01:03:29 pm »
Yea, i never read it but you probably have to preload them 120 degrees out of phase and at the very least turn them all on and off together, I think that was the peculiarity that allows easier 3 phase generation as normally each counter is separately controlled.
 


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