Lebowski's motor controller IC, schematic & setup, new v2.A1

Electric Motors and Controllers
arber333   1 mW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by arber333 » Jul 01 2018 1:12pm

Hi Bas

I am trying to design multi inverter application. I have some questions maybe others will benifit from.

1. Can Lebowski controller be run without throttle 2 connected? Do i have to connect its input to GND?

2. How would you go by using Fault/desat output of drivers? It is a open collector output of the driver module. Can i just use one fast PNP transistor to connect Enable pin to GND (it is the Reset function)? Or would you use another chip like arduino? What happens in code after reset if Enable pin gets 5V back? Would it be better to just cutoff 5V from Enable side of resistor?

3. About CAN pins.. If i dont use them, do i also have to connect them to GND? Or for that matter every pin i dont use?

tnx

Arber

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Lebowski   1 GW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by Lebowski » Jul 02 2018 12:35pm

Hi Arber,

Just to answer your questions:

1) yes it can work with only 1 throttle, in the setup menu you can specify only to use throttle 1 and not throttle 2.

2) I would indeed pull the reset on a fault detection, pull the reset (MCLR) to ground. This puts the chip in reset, a consequence of which being that all PWM outputs go to the 'off' state (so the complete power stage switches off). It does this very fast without software intervention. You may want to add something (flipflop) that keeps the chip in reset till you push a button to release it. You can also just reset it very short and allow it to start back up. In that case it will go through the normal startup, so first drive_0 where it will wait on throttle closed and/or motor standing still (dependent on what you enabled in the recovery menu).

3) every pin you don't use (including unused throttle inputs), I just leave them open :? through that's not the way you're officially supposed to deal with open pins. What is always safe is to connect the pin with a 4700 Ohm resistor to ground. If the pin is an input it will just see a ground. If the pin is an output it can easily drive the load of 4700 Ohm so no harm is done....

arber333   1 mW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by arber333 » Jul 03 2018 12:54pm

Another question

I have connected brain with computer and tried to programm it.
There were some problems with brain falling out of sync. So Q...

1. Do i have to have very precise voltage for 5V? I have constant 4.95V source. Very stable. Is it enough. I could use 3A variable PSU and set it to 5.1V, but do i have to?

2. What is the procedure for entering setup? It seems so quantum. Some times i get there but sometimes i cant. There is no rule...
Can you tell procedure A to B to C...

3. I use button to signal setup. Does this pin stays connected while in setup? In that case i have to setup a switch.

4. I have Prolific USB to serial gadget connected to TX, RX, GND. Should i connect 5V wire also?

5. What about voltage measurement? Do i need that? I intend to use 380Vdc so it would be catastrophic to just connect it to brain whatever the Rinput. Do i also put those pins to gnd via 4K7? Also i tried to change DC voltage value in menu but it just shows 6V even though i dont have anything connected.

tnx

Arber

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Lebowski   1 GW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by Lebowski » Jul 04 2018 1:55pm

1) 4.95V should be enough i its very stable, the chip automatically resets when it drops to 4.5V or so...

2) When the processor starts the first thing it does is look at the setup pin and go either setup or motor mode. After that there is no way to change the mode anymore. The processor starts: this is at power on or after a reset. So have the setup pin the way you want it when you power on, or WHILE you perform a reset.

4) I also only connect RX, Tx and GND, 5V not necessary

5) you dont need voltage measurement, you can connect the pin to ground. FOC accuracy will suffer a bit but not much.

arber333   1 mW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by arber333 » Jul 23 2018 8:01am

Lebowski wrote:
Jul 04 2018 1:55pm
5) you dont need voltage measurement, you can connect the pin to ground. FOC accuracy will suffer a bit but not much.
OK I have added 4K7 resistor to pins 5 through 8. That should also connect voltage measurement with GND. Now i tried to use 385V as battery voltage, but it wont accept HV and LV parameters. So i guess this is something i cant use?

On second thought, could i use Si8920BC isolated comparator with an opamp like MCP6001? What is the resolution of pin 6? Can i just connect this circuit that i already use in Johannes inverter?
voltage sense board.png
This could be added easily if your measurement would allow. For now i just use TL431 with large value resistor divider + variable pot to triger DC and precharge relay through PC817 opto on my terms. It works but is a bit crude. No extra IC needed that way though.

tnx

A

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Lebowski   1 GW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by Lebowski » Jul 25 2018 2:28am

I mean, it doesn't really matter what circuit you use, as long as the battery voltage is mapped to 2.5 to 5 V at the controller IC input. The mapping must be linear, and all possible battery voltages (so between completely full and empty) must fall in this range...

I like the isolated amp by the way, would be fun to try to replace the in the motor wires placed current sensors with this amp (as a cheaper alternative for lower power controllers). Use shunt resistors, measure and transfer the voltage to the 5V domain with this Si8920. Use bootstrapping to supply the motor wire side of the amp...

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by arber333 » Jul 31 2018 6:00am

Ampera inverter interface works.
I can drive ACIM motor with another brain.
Now i will try PMSM with Lebowski brain. Signals work on bench. I can save settings from Arlo video. 50V Leaf motor test awaits.

Fault pin on drivers is causing confusion. It is open collector output type and it is ACTIVE when in normal PWM operation. What is confusing is that whenever inverter is starting PWM this signal goes float for 10us and then back to active. Or when voltage goes under 25Vdc or when there is true short on IGBT...
It seems like that is not actually Fault signal, but more likely change of status signal or something. Does someone have any idea what kind of output it could be?

EDIT: Yeah... It definitely is Fault signal. Since i used it to trigger NPN transistor base EMI from 5V line caused Fault line to trip whenever PWM was activated. I will have to add more capacitance to filter out EMI. And i will use a transistor with higher threshold for base trigger.

tnx

A
Last edited by arber333 on Aug 01 2018 3:42am, edited 1 time in total.

arber333   1 mW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by arber333 » Jul 31 2018 8:01am

OK Bas you will probably laugh and Arlo will say "cool!" but hear me out anyway.

What if.... i used Volt inverter dual 6 bridge 500A modules in paralel with a single Lebowski chip control? Everything would be in paralel.
First I would connect phase outputs of each module to single 3phase Leaf motor. DC rail is connected together anyways.

Then i would use two SN74LS06 chips after DSPic to invert signal chip to provide correct signal timing and enough power for both power stages.
Now there comes a problem. Current sensors... How to provide accurate current control from both chips? Do you think i could use only single sensor set and double their sensitivity?
If i only used a single sensor set chip would think it operates under 1/2 power only. Could i just cut other sensors from the loop and hope that by derating power stage i would have enough safety margin? Inverter would provide 2x the power but i wouldnt care since i would use torqe control with throttle pedal.

I would of course derate each module to say 400A at 400V. But do you think i could do it? It would be a sweet package for the power.

A

arber333   1 mW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by arber333 » Aug 02 2018 7:34am

Check this out!

https://tspace.library.utoronto.ca/bits ... Thesis.pdf

I found this while browsing for paralel controller design. According to this two inverters can run together on the same DC bus as well as AC bus. Well control must be tight, but it could be done. Want to try some day?

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Lebowski   1 GW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by Lebowski » Aug 02 2018 3:18pm

I will have a look after I am back from holiday... Am on Tenerife now, where it is nice and cool :D

arber333   1 mW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by arber333 » Aug 23 2018 4:07am

Hi Bas

I found interesting chip that can measure outside thermistor and output digital signal. Is it possible to adapt this to your code so we could use existing (scavenged) inverter signalling?

https://datasheets.maximintegrated.com/ ... AX6682.pdf

tnx

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by fechter » Aug 23 2018 8:17am

arber333 wrote:
Jul 31 2018 8:01am

Now there comes a problem. Current sensors... How to provide accurate current control from both chips? Do you think i could use only single sensor set and double their sensitivity?
If i only used a single sensor set chip would think it operates under 1/2 power only. Could i just cut other sensors from the loop and hope that by derating power stage i would have enough safety margin? Inverter would provide 2x the power but i wouldnt care since i would use torqe control with throttle pedal.
If each section has it's own current sensors, you could take the signals from both and electronically add them. This could be done analog or digitally.
Another approach would be to route the wires from both modules to a single set of sensors. I don't know how it looks or whether that would be feasible.
"One test is worth a thousand opinions"

arber333   1 mW

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by arber333 » Aug 28 2018 5:26am

Hm... yes! I remember i have 3x 1200A sensors that are powered from +/-15V. I would have to convert that to 5V then and amplify, but it would be feasible :). Nice!
It would mean i would have to add a large box on Ampera inverter side to get cables through sensors. Did I mention i like mechanical problems more than electrical. :lol:

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Re: Lebowski's motor controller IC, schematic & setup, new v2.A1

Post by bearing » Aug 28 2018 5:59am

arber333 wrote:
Aug 28 2018 5:26am
Hm... yes! I remember i have 3x 1200A sensors that are powered from +/-15V. I would have to convert that to 5V then and amplify, but it would be feasible :). Nice!
It would mean i would have to add a large box on Ampera inverter side to get cables through sensors. Did I mention i like mechanical problems more than electrical. :lol:
Usually those sensors gives an output signal which is a small current (that is proportional to the measured current). So its just a matter of connecting some resistors of the right size on the output to get a 0-5V signal. But check the offset and noise specs, they might not be good for a sensor of that range (1200A).

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