kaipyroami

Sensored BLDC BoosterPack

26 posts in this topic

I am interested in making a BLDC BoosterPack for a wide variety of motor applications.

Perhaps with modifiable interchangeable power fets for different applications.

 

Anyone else interested in this too?

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I've been thinking about making an ESC board for quadcopters based on the C2000 launchpad (on its way :-) ).

I believe the Piccolo's high-resolution PWM outputs would make it an excellent candidate for controlling 4 hobby-BLDC motors.

Most Hobby-BLDCs are sensorless, so one must use the inactive windings to sense the phase, but I believe it should be fairly easy to make a board that can handle both situations with little or no physical modification.

 

Cheers,

Itamar

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I believe there may be a TI BoosterPack in the works that does exactly what ya'll are suggesting. I think they are using something like the DRV8312. Also, we already have software that can do BLDC control very well :)

msptest6 likes this

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perfect!

 

I am interested in having sensor support simply for high torque start up situations (RC cars, tracked vehicles etc.)

 

But my intentions are for both sensored and sensorless applications. I think this would be a VERY good thing if TI came out with a BoosterPack so I don't have to do it on my own... ;)

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DRV8312 sounds great. Q3/Q4 not so much... But if you want to make a multi-purpose board with different kinds of FETs, DRV8312 sounds not so great either... ;)

 

As for BLDC control software, I can say that the motor control library is excellent. The examples, however, should only be used as just that: a way to learn the basics, then implement your own application.

 

Cheers

TomKraut

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my plan was to use proper gate drivers and then have a way to use a variety of fets from there.

I will have to look into this more to fully understand what I am doing. :D

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The one currently in progress at TI is based upon the DRV8301/2 and will utilize Texas Instrument's NexFETs.

Awesome! news. Thanks for keeping us in the loop.

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Yes, I haven't registered as a TI employee on here yet but saw the post and thought I would chip in. If anyone has any suggestions/features they would like to see, feel free to chime in and I can pass the ideas along.

 

Nick

kaipyroami likes this

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The one currently in progress at TI is based upon the DRV8301/2 and will utilize Texas Instrument's NexFETs.

That's nice to hear. Any idea whether there will be one or two drives per boosterpack. That would help alot of robot projects spring up.

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I don't think you could cram more than one driver + fets on a BoosterPack. I have a board next to me that is approximately the size of a BoosterPack and there is no way to fit another driver + fets on it, because they don't allow parts directly under them on the bottom side. Besides, cooling them would be a nightmare!

 

@Nick: You don't know by any chance if there is an update for the DRV8301/2 datasheet planned? The current one is a year old and missing A LOT of information which is available through threads on e2e... ;)

 

Cheers

TomKraut

msptest6 likes this

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This is a single inverter (DRV8302 + NEXFETs) for the BoosterPack. 24V 10A.

We have a different development board with two inverters (single controlCARD inferface), each 24V 10A that is also in progress. This one will also include an optional dyno bench, using one of the inverters as the dyno and the other under test/control.

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Chris said it, one driver per board. Simply not the room for two while maintaining the BoosterPack theme. Also as Tom said, thermal dissipation would be difficult.

 

@Tom

Don't know anything myself but I'll ask around. I have found the best reference for hardware designs to actually be the DRV830X EVM in control suite under development kits.

msptest6 likes this

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That's true, if you are building hardware with TI components, the EVMs are always your best bet. However, sometimes you need more information because of the simple fact that you are not just copying an EVM but also building your own custom hardware.

A specific example would be the formulas necessary to find the values for the external components for the buck converter integrated into the DRV830x. They are not in the datasheet! You have to search e2e to find out that it's practically a TPS54160 and than have to use that datasheet as a reference.

It's unlikely that we would benefit from a new datasheet for our current project, because we have just meddled through and so far everything seems just fine. But the particular datasheet for the DRV830x is just not up to the standard I expect from a TI product. And if you are releasing a BoosterPack with it, that might become a problem...

 

Cheers

TomKraut

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This is a single inverter (DRV8302 + NEXFETs) for the BoosterPack. 24V 10A.

We have a different development board with two inverters (single controlCARD inferface), each 24V 10A that is also in progress. This one will also include an optional dyno bench, using one of the inverters as the dyno and the other under test/control.

 

Would it be possible to adapt this boosterpack schematic design to use higer amperage fets?

What I mean is, if I design a basic control with it for a motor under low torque could I then make a new board with 40A - 100A capable fets with minimal tuning?

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Would it be possible to adapt this boosterpack schematic design to use higer amperage fets?

What I mean is, if I design a basic control with it for a motor under low torque could I then make a new board with 40A - 100A capable fets with minimal tuning?

 

The hardware on the BoosterPack will not be able to support such high currents (connectors/sense resistors/traces/etc). Due to the size/cost/thermal limitations we are looking at it is simply not possible to support that much power. I would have to send you in the direction of this EVM http://www.ti.com/tool/drv8302-hc-c2-kit for that kind of hardware.

 

I'm sure you could a find a way to put different FETs on the BoosterPack but the results would be unpredictable.

 

Regards,

Nick

kaipyroami likes this

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Just to throw this out there, I did some work with bldc motors using msp430. See images below. In my opinion c2000 is a little over kill especially for sensored motor control but agreeably cool.

 

post-936-14264717215198_thumb.jpg

 

post-936-14264717215384_thumb.jpg

 

post-936-14264717215547_thumb.jpg

msptest6 likes this

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...well that looks awefully like a motor driver for a quadcopter...Nice work!

 

For a sensored BLDC application we are certainly overkill, but the beauty of our device is that we have the hardware and software to do sensorless control.

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Now if only it flew haha...

 

I managed to get a form of instaspin bldc running on msp430g2553 on the first board but haven't touched it in awhile to optimize. My big problem was running the advice fast enough for high KV motors. I think I have a scheme now just need time to implement.

TI_Trey and msptest6 like this

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Now if only it flew haha... I managed to get a form of instaspin bldc running on msp430g2553 on the first board but haven't touched it in awhile to optimize. My big problem was running the advice fast enough for high KV motors. I think I have a scheme now just need time to implement.

Looking forward to it.

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...well that looks awefully like a motor driver for a quadcopter...Nice work!

 

For a sensored BLDC application we are certainly overkill, but the beauty of our device is that we have the hardware and software to do sensorless control.

I could not figure out the mounts for the motors.

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It's ok because mounts are not on the board. My goal was to have a separate frame for that. The motors that I wanted to use were too big and powerful to attach to the pcb

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