noob BLDC conroller - Just started

[newbiebiker]

hi guys,
i am noob in this field, planned to convert my bicycle in electric bicycle, but controller is the main thing, if we designed (created) means, we can workout easily, so i planned to create controller, here i need your help guys.


Documentation (hope this may help other newbie like me) :
http://ebikecontroller.blogspot.com/

Motor : 48V 2000W BLDC
Target : simple BLDC controller.
Deadline : 1 year from today (August 2016)

i just know the word controller, but a bit on visiting/reading this forum i understood few more things.

just drawn the thing that i known about ebike components needed as schematic.

About controller :

My question is,

how to choose the microcontroller, IGBT driver, Mosfets, because theere are plenty in it.

Is microcontroller/IGBT driver/Mosfets are independent..?? that is if we choosed one microcontroller means, we have to use any specific IGBT or we can use an IGBT driers, like that if we choosed some IGBT driver means, we have to use specific MOSFET ? or all 3 three are independent ?

 

[newbiebiker]

For operating 48V 2000W BLDC motor , is
2 x 8000mAh 3S1P 30C , 3 Cell , 11.1v is enough ? or i need more..?

or how to calculate battery requirement

 

[cycborg]

So do you just want to get something running, or are you an electronics hobbyist with a goal of designing/building your own controller? You can buy a controller at this power level from various sources relatively cheaply, whereas a design-and-build-from-scratch is a significant undertaking. Even if you want to pursue this, I’d suggest getting a commercial controller to get you rolling and to have something to swap out for testing.

Anyway, as to your specific questions:

Regarding the battery, sounds like you might be coming from the RC world where low-voltage, high-current setups are more common. Typical e-bike systems are 10s-20s. And for capacity, figure somewhere between 15-30 Wh/mile depending on how fast you want to go, your terrain, the weight of you and your bike, etc. 6s 8 Ah is less than 200 Wh, which could be just a few miles of range. So, yeah, more capacity for sure, and strongly recommend more volts.

Regarding the microcontroller, gate drivers, and MOSFETs: First of all, not sure why an IGBT driver would be paired with a MOSFET. Forget about IBGT; let’s just assume we’re talking about MOSFET gate drivers and MOSFET switches. The driver needs to be capable of supplying sufficient current quickly enough to overcome the MOSFET’s gate charge requirement to switch the MOSFET quickly, so some care needs to be taken in matching these components. The microcontroller-driver matching is not so critical.

There’s much more to it than this and I’m not an expert, so I’d search on here for those who have worked on such projects and see what works and what the pitfalls are. Good luck.

 

[newbiebiker]

i hope to start with this battery (because these LiPo batteries are costly) 8000 mAh 3S1P 30C 11.1V
have 2 batteries only.

2P - 8000 mAh, 11.1V = 177.6 Wh 11.1V
2S - 8000 mAH, 11.1V = 088.8 Wh 22.2V
But my Motor is 48V 2000W, will this 22.2V able to run that motor ?

Still i am reading lot about IGBT drivers, Each MOSFET need each driver..? that is, if 18 MOSFET output designed means, we need 18 IGBT in IGBT driver ?

 

[Arlo1]

i hope to start with this battery (because these LiPo batteries are costly) 8000 mAh 3S1P 30C 11.1V
have 2 batteries only.

2P - 8000 mAh, 11.1V = 177.6 Wh 11.1V
2S - 8000 mAH, 11.1V = 088.8 Wh 22.2V
But my Motor is 48V 2000W, will this 22.2V able to run that motor ?
The voltage controls the top speed so if 48v give you 50km/h 22v would give you about 23km/h

Still i am reading lot about IGBT drivers, Each MOSFET need each driver..? that is, if 18 MOSFET output designed means, we need 18 IGBT in IGBT driver ?

You need 6 IGBT or FET divers they are the same thing. Just make sure they have the ratings you need. If you want 18 mosfets then each phase will have 3 positive and 3 negative mosfets 1 driver will run 3 mosfets but you might need to use a boost stage depending on the system so it would go like this
Controller IC ( dsPIC ) > FET/IGBT Drivers > Boost transistors > mosfets

 

[SjwNz]

But my Motor is 48V 2000W, will this 22.2V able to run that motor ?

Yes you can still run that motor at 22V but you wont go very fast. I started out on 22Volts when I was using RC speed controllers
but did not take long before I went up to 40 to 50Volts.

 

[Drunkskunk]

But my Motor is 48V 2000W, will this 22.2V able to run that motor ?

It would help us to know exactly what motor you have, and also to know what your expected goal is.

22 volts will make a motor spin, most likely. But if it was a motor with a KV based on 48 volts, you're going to be running at less than half speed.

 

[Arlo1]

i understood controller with 6 Mosfets or multiples of 6 is good,
controller design mainly depends upon max amp and max volt needed,

eg:
for 2000 watt motor
50 amp x 40v = 2000w, so we have to design 50A 40V controller for 2000w motor ?


Motor :
http://www.uumotor.com/shop/10inch-brus ... motorcycle

From your post on my thread.

If you want 50amps DC then you will need more peak phase amps but the DC phase amps with good code can meet or exceed the RMS phase amps.
So for now lets work the math like this Lebowski's controller brain does not have field weakening but it does do fairly well without it so lets assume you can get the same peak DC amps as the max RMS phase amps. As a rule RMS is .707 x the peak phase amps. If you want 50a DC you will work the math like this.
50 DC = 50 RMS = 50/.707 = ~70 amps peak. You will need each side of each phase to handle 70 amps peak. That is 1 really REALY good mosfet for every hi and low side of each phase (6 really good mosfets) or 2-3 cheeper mosfets in parallel per hi and low side (12-18 mosfets total)
Also watch out you might not be able to get 2000 watts from that motor at 40v. A motors limit is its PHASE current.

 

[newbiebiker]

oh, so how to decide the voltage and amp requirement of controller for below motor ??

10inch Brushless Hub Motor 48V 2000W
Model QS10-U5
http://www.uumotor.com/shop/10inch-brushless-hub-motor-2000w-for-electric-scooter-motorcycle

is this 48V and 2000W (these 2 values) specification of motor decide the controller specification or other values, that is which value of motor decide the controller voltage and ampere.

For voltage ::
what is understood is => we can max 48V, if we crossed 48V , then overheating, result in motor damage ??

For ampere :
48 V x 41.66 A = 2000W,
so 41.66 DC = 41.66 RMS = 41.66 /0.707 = 58.92 Ampere

so i have to design 60 A , above 48V controller for this 48V 2000W motor ?

 

[SjwNz]

For voltage ::
what is understood is => we can max 48V, if we crossed 48V , then overheating, result in motor damage ??

This thread should answer your question about running you motor at a higher voltage.
https://endless-sphere.com/forums/viewtopic.php?f=30&t=71266

For ampere :
48 V x 41.66 A = 2000W,
so 41.66 DC = 41.66 RMS = 41.66 /0.707 = 58.92 Ampere

so i have to design 60 A , above 48V controller for this 48V 2000W motor ?

You could be looking at phase currents up around 60 to 80amps , which is the currents your motor will see, put the battery
will see the avg current of around 40amps, these currents are limited by the controller.
You will need a MOFETS that can handle more than the peak current, so something like the
IRFB4110 maybe? ok for your power level.

For your max controller voltage, I think around 25% more than your max battery voltage, so around 60volts. if the IRFB4110s fets were to be used they can handle 100volts so the only other parts you need to look at are the DC-Link Caps and the power supply that steps down the battery voltage to run the Micro Controller and gate driver chips.

I have only made 1 controller so I am not the best at this, but hope this gives you some ideas.

 

[newbiebiker]

For voltage ::
what is understood is => we can max 48V, if we crossed 48V , then overheating, result in motor damage ??

This thread should answer your question about running you motor at a higher voltage.
https://endless-sphere.com/forums/viewtopic.php?f=30&t=71266

For ampere :
48 V x 41.66 A = 2000W,
so 41.66 DC = 41.66 RMS = 41.66 /0.707 = 58.92 Ampere

so i have to design 60 A , above 48V controller for this 48V 2000W motor ?

You could be looking at phase currents up around 60 to 80amps , which is the currents your motor will see, put the battery
will see the avg current of around 40amps, these currents are limited by the controller.
You will need a MOFETS that can handle more than the peak current, so something like the
IRFB4110 maybe? ok for your power level.

For your max controller voltage, I think around 25% more than your max battery voltage, so around 60volts. if the IRFB4110s fets were to be used they can handle 100volts so the only other parts you need to look at are the DC-Link Caps and the power supply that steps down the battery voltage to run the Micro Controller and gate driver chips.

I have only made 1 controller so I am not the best at this, but hope this gives you some ideas.

got it.
so max voltage will be 60V, and current will be 80 amp at peak (from their data), so i planned to choose little more, say 100 amp

FInally i have to design controller of 60V, 100A for 48V 2000W, with 80A peak current BLDC motor
Yeah, IRFB4110 is right guy, as it withstant 100V 180A

 

[SjwNz]

You should still look at other 6fet designs that are using the IRFB4110 and see what power they got out of them as I am not sure if they will handle 2kWs.
Otherwise if the don't mind spending some more money get the IRFP4468. I am using these and will easy get to 3kW.

 

[Arlo1]

You have to look at all the limits. a irfb4110 is limited by its legs and that's 120 amps then you need to look at figure 8 the safe operating area they are not rated for the same amperage at all voltages. If you make everything perfect in your controller you will still be at the very limit of a irfb4110 fet for what you want. Unless you run 2 in parallel and make it a 12 fet.
Or run 6 4468 fets. I have seen good results from them. There is a lot of other fets out there. Look at TO247 and TO264 as well to make sure you select what you think you want. I spend 1000s of hours looking at fet data sheets.

http://www.irf.com/product-info/datasheets/data/irfb4110pbf.pdf