Enova(!) Parameters

[tom3141]

I've been on and off here over the last few years but I finally got my Suzuki Cappuccino conversion driving for the first time today. Overall it went pretty well but I do have some issues with inverter settings that I would welcome any advice on.

I have one of the Enova 90kw motors (yes, I know) driven from the Enova inverter with one of Damian's combi boards.

I have been fiddling with the inverter parameters a lot today but I'm having problems with it tripping (I assume overcurrent) unless I'm really gentle with the throttle. I originally used settings of boost 6000, fweak 121, fslipmin 1, fslipmax 2.8, ampmin 4. This felt smooth and nippy but if I wasn't really careful and progressive with the throttle it would just cut out (not really any juddering or rocking just a clunk). If I tried to floor the throttle it would just immediately cut out without moving. I upped the occurlim to 800 and still had the same issue.

I've played around with the throttle settings and found that if I reduced the throttle limit down to 20-30% it would work ok although sluggish. I then experimented with putting the throttle limit up to 100% but altering some of the other parameters. Reducing throtramp helped a lot and I ended up with it set to 1. I also increased slipstart to 100 and set both fslipmin and fslipmax to 1. I assume this basically means my slip value is always 1. With these settings I can drive the car smoothly up to around 30mph although it is obviously sluggish pulling away. However I can still make it trip if I put a high load on the motor at 0rpm such as trying to climb a kerb from a standstill.

Any suggestions on what the problem could be or what parameters to try? Also, I know there have been lots of issues with encoders on the Enova motors, is it possible that this is encoder related?

Thanks,

Tom

[Kevin Sharpe]

Any suggestions

Dump the enova motor

Damien spent a year trying to get this motor to work and eventually gave up.

[arber333]

You may want to make your own encoder. Use either Arduino optical sensor or a toothed wheel and reluctance sensor. Any gap count from 30 to 90 will do I think.
See here...in slovenian language, pictures though...
https://mazdamx3ev.wordpress.com/2015/0 ... er-senzor/

[EVElvis]

Hi Tom
Congrats on getting your car driving!
I too am trying to get the enova inverter and Hyundai motor working. I have had it run smoothly in the past. It is just a 3 phase induction motor from what I can see. I am now suspecting issues with encoder signal, and will post what I see on my scope this morning asap. I can see some interference.
Im still running 50V test pack and have car on axle stands, so little load, but have wondered whether that is too low to get any smooth start. I have had it run better 3 years ago with old software. I have just put last but one revision software in, and have been struggling more with that.
I suspect different encoder will be the way to go, but I will try and learn what I can first.

[tom3141]

Any suggestions

Dump the enova motor

Damien spent a year trying to get this motor to work and eventually gave up.

I know Damien has struggled to get this motor working. I have far less experience and knowledge than Damien but would like to try to get my head around the issue with these motors. What seems strange to me is that they must have worked in the original application and it can’t be that there is something fundamentally wrong with all of these motors. They are just 3 phase AC induction motors so isn’t it just a case of getting the parameters correct or sorting the encoder (if that is the problem)?

You may want to make your own encoder. Use either Arduino optical sensor or a toothed wheel and reluctance sensor. Any gap count from 30 to 90 will do I think.
See here...in slovenian language, pictures though...
https://mazdamx3ev.wordpress.com/2015/0 ... er-senzor/

I’m happy to look into making a new encoder if that proves to be the problem but from my understanding it doesn’t make sense to me why the encoder would cause this issue. I don’t see why limiting the max throttle would help if it’s an encoder issue. Even with the original settings I had, the motor will spin up smoothly to a decent speed if I’m smooth with the throttle. It also trips sometimes when the motor is at 0rpm, for example if you hold it on an incline and then try to give it some more throttle. Could the encoder still be the cause with these symptoms? I will try to investigate the encoder further but don’t have access to a scope at the moment.

Hi Tom
Congrats on getting your car driving!
I too am trying to get the enova inverter and Hyundai motor working. I have had it run smoothly in the past. It is just a 3 phase induction motor from what I can see. I am now suspecting issues with encoder signal, and will post what I see on my scope this morning asap. I can see some interference.
Im still running 50V test pack and have car on axle stands, so little load, but have wondered whether that is too low to get any smooth start. I have had it run better 3 years ago with old software. I have just put last but one revision software in, and have been struggling more with that.
I suspect different encoder will be the way to go, but I will try and learn what I can first.

I had mine running off a 30V psu before I got my battery pack sorted. I was able to get a smooth startup at 30V so 50V shouldn’t be an issue.

[Kevin Sharpe]

Any suggestions

Dump the enova motor

Damien spent a year trying to get this motor to work and eventually gave up.

I know Damien has struggled to get this motor working. I have far less experience and knowledge than Damien but would like to try to get my head around the issue with these motors.

I fully understand and wish you luck

[johu]

That motor is a mystery to me as well, I spent some time with Damien trying to remotely tune it.
I guess you indeed want to keep slip constant (e.g. by slipstart=100) and find a boost/fweak setup that never trips. Then add slip.

[tom3141]

Investigated some more this evening.

It appears it is an encoder related issue looking at the rpm vs throttle graphs on the web interface.

With the wheels off the ground and using the throttle gently the rpm values seem fine. There are no spikes and the rpm values seem sensible. However if I put the wheels on the floor and try to hold the car on a slope, the rpm graph is all over the place. Rpm values were spiking up to 1000rpm when the motor wasn’t even turning. There are no spikes if no throttle is applied.

Does this sound like an interference/shielding issue? The encoder seems to work until the motor is under higher loads and then something is causing the readings to go haywire.

[arber333]

Investigated some more this evening.

It appears it is an encoder related issue looking at the rpm vs throttle graphs on the web interface.

With the wheels off the ground and using the throttle gently the rpm values seem fine. There are no spikes and the rpm values seem sensible. However if I put the wheels on the floor and try to hold the car on a slope, the rpm graph is all over the place. Rpm values were spiking up to 1000rpm when the motor wasn’t even turning. There are no spikes if no throttle is applied.

Does this sound like an interference/shielding issue? The encoder seems to work until the motor is under higher loads and then something is causing the readings to go haywire.

That is exactly what it is. I recommend you scrap encoder and use your DIY one optical encoder like i suggested. You must use lycy shielded cable and couple the cable on inverter end only.
Of course motor needs to be connected to chassis and/or inverter casing by a thick braid. This is extremly important! My inverter with Leaf motor wont even start if it is not grounded to chassis.

[Jack Bauer]

If you watch my last video on the Range Rover P38 which unfortunately uses two of those motor you will see the exact same thing. The issue is the HEDS encoder. Its junk. I'm now looking at how to fit a different type of encoder on there.

[arber333]

If you watch my last video on the Range Rover P38 which unfortunately uses two of those motor you will see the exact same thing. The issue is the HEDS encoder. Its junk. I'm now looking at how to fit a different type of encoder on there.

True...maybe it would be better to just find a way to put alu collar on driveshaft and fit a toothed wheel with 64 teeth to its side. I am thinking of doing that to my speedo, since magnet doesnt work good....

[Jack Bauer]

Won't work Arber. Too much slop in the gearbox. Needs to be on the motor shaft.

[arber333]

Won't work Arber. Too much slop in the gearbox. Needs to be on the motor shaft.

Ah so you still have the gearbox inside? OK.
Did you see this? https://www.rls.si/en/rmf44-rotary-magn ... tal-flange

That would be mounted behind one motor on a flange. On the shaft you would install polarized magnet which would transmit angular position. You have different flavour of signals. AB, ABZ, rising edge, UVW, RS422, resolver angle etc... I use it with my Leaf motor and it works really good.

[tom3141]

Thanks for your comments.

I’m not using the gearbox but there is still a fair bit of slop on the splines so the encoder definitely needs to be on the motor.

I’ve just double checked the encoder cable and motor inverter ground connections. My motor is mounted directly to the subframe and there is good continuity between the motor case and the inverter ground. However I have found a potential issue with a ground loop due to the encoder cable shielding. I had previously seen Damien’s mention of the encoder cable being grounded to the motor case so had disconnected a wire that was connected to the motor case underneath the encoder cover plate (potentially the wrong one?). Today I unplugged the encoder connector from the inverter and found that the casing of this connector was still connected to ground so will create a loop when plugged into the inverter. I’m guessing there must be another connection between the encoder shielding and motor case that I missed. I’ll investigate later.

[tom3141]

So I took the encoder cover plate off and discovered the connector casing was no longer grounded. Put the cover back on again and it still wasn’t. Only thing I can think is that I had previously trapped the shield wire between the cover and the motor.

Anyway, I tried it again and there is definitely a significant improvement. It wouldn’t trip with my limited settings and was harder to trip with some slip added. However, looking at the rpm graph there are still some wobbles in low speed, high load situations. I’m going to try to improve the routing and shielding of the encoder cable befor I give up and go down the replacement encoder route.

[joromy]

How does your angle plot look like, at stand still and manual turn of wheel?
Like this:
viewtopic.php?f=2&t=731#p10711

[tom3141]

I don’t think I can get an angle plot. I’m on old software and didn’t want to update until I had it running to prevent any potential new problems arising.

I did get a couple of photos of the weird rpm plot I’m getting. This is with the inverter on and set to forward but with no throttle input. If it’s in neutral the rpm plot is flat. It will repeatably produce one of these two plots.

Seems really strange that it’s such a neat graph and can be produced consistently.

I’m going to start looking into a different encoder but if those plots mean anything to anyone then let me know.

[joromy]

Seems really strange that it’s such a neat graph and can be produced consistently.
I’m going to start looking into a different encoder but if those plots mean anything to anyone then let me know.

Did test this today (Siemens ACIM motor)
I got zero RPM at standstill, in RUN mode and off mode.
I still get angle changing from 0-360, so I guess that is normal.

[EVElvis]

Hi Tom
Please can you let me know what software version you use? Does it have the parameter encflt available as im sure this is what made my car drivable in the past.
It would be fun to be able to drive the car again With the software - 4.76 I cant set parameters to get the car driving.
Im just looking into the encoder HEDS-5605-F13 datasheet to see if there is any details that may help - I would be surprised if they are poor quality or not capable of working well? I guess it is easier to pick up fewer pulses per rev amongst the noise, and 256 on this encoder may not help?
Cheers
Tim

[tom3141]

I’m on v4.0. I don't think it has the encflt parameter.

[arber333]

What about if you would order and replace your encoder with that part? HEDS-5605#C06 has only 100cpr so this means filter would have less trouble recognizing signal.

Also I saw decoupling caps can do wonders here. You may try to add a 102 or 103 capacitor directly on encoder connector from channel A/B to GND.

[tom3141]

What about if you would order and replace your encoder with that part? HEDS-5605#C06 has only 100cpr so this means filter would have less trouble recognizing signal.

I’ve considered that. I took the encoder off yesterday and managed to break it in the process so I’m now definitely replacing it with something. It’s very difficult to remove the tiny grub screw that holds it onto the motor shaft. The whole thing is incredibly flimsy, the slotted disc is so thin and fragile. I can imagine that any vibration or resonance within the motor could easily vibrate the disc enough to give false readings.

I also think that the 256 pulses is limiting my motor speed to just over 2000rpm as it won’t accelerate past this point and starts vibrating horribly.

I’ve purchased a cheap Arduino type IR speed sensor which I’m going to try to get mounted in the next week. I’m going to make a slotted disk which will reduce the number of pulses per rev. Is there a minimum recommended number? I’m thinking 32 or 36 per rev. I think the minimum you can set in the parameters is 8.

[arber333]

I’ve purchased a cheap Arduino type IR speed sensor which I’m going to try to get mounted in the next week. I’m going to make a slotted disk which will reduce the number of pulses per rev. Is there a minimum recommended number? I’m thinking 32 or 36 per rev. I think the minimum you can set in the parameters is 8.

You may go the optical sensor way. I used it a long time as a single pulse sensor. You will want to adapt your main board acc to Johannes instruction.
I recommend you also use a different cable. Use Lycy 3pole shielded cable and connect shield to chassis. Also motor and inverter have to have good connection AND their casing both need to be connected to chassis.

I recommend you make 60 pulse disc since it is easier to make divider to 60 holes from 360deg. It worked for me. It will be a single channel connection though.

You can also just buy a HEDS-5605#E06 sensor (which has optical encoder inside i am sure!) and make your own cable and connector. You need to consider little shaft diameter and other mounting. There is also a connector to get there...
See here it recommends 2K7 pullup resistors to 5V for all inputs. Johannes uses 4K7 i think. Could that interfere with the logic of inverter?
http://www.farnell.com/datasheets/79134 ... 1573669857

I am sure we should not call the motor as "crappy". It is just a motor. You need to figure out how to drive it and it will be fine.

Also once i found a motor with burned up winding on one phase. It was driving untill we load it with more than 125A per phase and then it shorted. Problem was not unlike yours. Rotor showed signs of flooding. You may want to take a look inside your motor and check windings.
Maybe the car was under water?

[tom3141]

Arber, what alterations did you make to the main board in order to use the optical sensor?

[tom3141]

Bit of an update...

I bought one of these to have a play with - https://www.ebay.co.uk/itm/Infrared-Spe ... 2749.l2649

I 3D printed a mount and a slotted disk (36 slots) and gave it a go. I wasn't sure on the electronic side of things if anything needed changing on the inverter board but I wired it in exactly the same as the old encoder (with the same cable) and tried it.

It appears to work (almost). The interference I was getting when the motor is not turning seems to have gone. After tweaking some of the parameters it is starting up much better. I can add some slip and floor the throttle without tripping it. It's not perfect but I think there might be some more tweaking I can do with parameters. I'm not getting any funny rpm readings on the graph in the software.

There is one new problem though - whenever the motor hits around 900rpm the motor starts making some loud clonks. If you continue they get worse and the inverter trips. It's repeatable and always at the same rpm. This is with the wheels spinning off the ground. Any ideas? It's similar to what was happening at around 2000rpm with the old encoder, I assumed that this was hitting the frequency limit of the filter due to the high pulse count of the old encoder. However, with the pulse count of the new encoder this should't be causing any problems.