Buick Lacrosse 2012 e-assist moto-alternator

Electric Motors and Controllers
udaykishanr
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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by udaykishanr » Mon Sep 11, 2017 1:13 pm

e-vektor wrote:Actually I work for a company writting software for dynamometers. This research is partial hobby (for the e-ATV), and partial for investigation about the needs of dynamometers when used with electric motors. Torque and Power are the basic variables you get in a dynamometer, even for an inertial dyno (with the suitable amount of mass). For this project I used SP5 DAQ (braked) that also controls an eddy current brake and acquires load cell (torque). This allows me to sweep tests but also stationary tests (rpm constan)
The purpose of a standard dynamometer is normally measuring HP and TQ, but with electric motors I think the next interesting variable is efficiency. For that purpose in some tests I acquired battery voltage and current (Curtis+Motor is considered a black box) and then with the battery power (V*I) and mechanical power (KW) it is easy to calculate efficiency.
This induction motor had a peak of about 86%, but I didn't finish the software for creating a whole map, so I cannot be sure if there is another peak somewhere- Anyway 86% is good for me. And also, keep in mind that when driving the motor to max torque it can decrease up to 65% or so.

And regarding the question about torque, normally with electric motors there is a direct relationship between current and torque. But with induction motors it also changes with slip (difference between mech speed and electric speed), so you will need some dyno if you want to have the resulting torque.

And regarding the graphs, I still have doubts about what is the true nominal speed. According to my calculations it should be around 2000 rpm as stated in the previous post. Indeed as you can see how torque decreases from this point, since the inverter has no more available voltage to follow the increasing speed, then current starts to decrease. But somehow the inverter is able to still increase the power up to 3200 rpm (other motors have flat power at this point), and then it quicly falls in THIS test, but when performing a slow sweep from 3200 to 3700, I can see that the inverter little by little is able to increase AGAIN the torque, and provides a no so deep fall
Another interesting fact: I think the actual TQ graph from 0 to 2000 rpm should be almost flat, but the inverter needs more time to adjust its PIDs, it does not behave in the same way during an acceleration transient

How much Amps can your inverter handle?
e-vector,

Thanks for that elaborated explanation.
Well, the Inverter which I made handles upto 300A (I am using a 24V Battery), however I can increase its current capacity handling by changing the MOSFETs that are in the inverter.
Till now, I thought 300A will be good enough to run the motor for my application (for the nature of the load I am using).
I am using V/f control method to vary the speed of the motor. I have the freedom of varying frequency with the set up I have.
I am trying to run the motor at different frequency values, with the motor loaded with a blower fan.
At 200Hz, Stator speed is 3000RPM and Rotor speed is 2700RPM (measured), which amounts to a slip of 0.1.
If I increase the frequency further the rotor falls out of synchronism since the battery voltage is only 24V and V/f ratio is not maintained further.



The problem with me is... like I said in the previous post, I cannot able to track the torque and speed characteristics continuously.
I have "Fluke 433 Three-phase Power Quality Analyzer", but I think this wont give torque value. It displays Power output in KW and from that I can calculate torque by using one of the formula.
The stuff which you spoke in the post regarding dynamo meters is new to me. I need to get familiarize with using dynamo meters.
Since now you know what I am looking for, can you recommend a basic (easy to use) dynamo meter which outputs the continuous torque speed values when the motor is loaded externally? I am testing the motor by loading it with a blower fan (2nd order).

Thanks a lot
Uday

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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by e-vektor » Mon Sep 11, 2017 4:56 pm

300A is ok for this motor but 24V is very low as its nominal voltage in star topology is 115V, so you are always working in the field weakening area, because over 400 or 500 rpm the voltage cannot be increased
V/F is not a good method for traction because it cannot change the voltage fast enough to adapt itself to the changes on load. If you need to climb an incline it will quickly reach to some "short-circuit" as voltage will be too high for current speed. The preferred control method is vector because voltage can change very fast to keep current constant.
Although if you load is constant (like the fans you mention) it may be ok

for measuring torque you need a dynamometer, but as soon as you put some load on the motor the V/F method will reach an overcurrent condition.
Basic dynos are: inertial: just put a steel mass that makes the acceleration slower (weight or inertia have to be calculated to the actual rpm, OR the rpm has to be changed in the flywheel to provide higher load to this high torque motor). You could use an inertial kit, which only needs the flywheel speed (if you need more info please send me a PM)
But preferred dynos are braked because you can also control the amount of load (slow ramps or fast ramps), and also you can create a stationary load, for instance to see the evolution of the inverter algorithms with time. For this dyno you will need an eddy current brake and a braked electronic kit with a load cell, a brake power supply, etc
Both are relatively expensive, first one can cost from 1500 eur (there are also cheaper DAqs but I didn't test it), and braked can cost 6000 eur or more (only the brake can cost 2500 eur or more)
As dyno have become popular, there is some used parts in the market


udaykishanr wrote: e-vector,

Thanks for that elaborated explanation.
Well, the Inverter which I made handles upto 300A (I am using a 24V Battery), however I can increase its current capacity handling by changing the MOSFETs that are in the inverter.
Till now, I thought 300A will be good enough to run the motor for my application (for the nature of the load I am using).
I am using V/f control method to vary the speed of the motor. I have the freedom of varying frequency with the set up I have.
I am trying to run the motor at different frequency values, with the motor loaded with a blower fan.
At 200Hz, Stator speed is 3000RPM and Rotor speed is 2700RPM (measured), which amounts to a slip of 0.1.
If I increase the frequency further the rotor falls out of synchronism since the battery voltage is only 24V and V/f ratio is not maintained further.



The problem with me is... like I said in the previous post, I cannot able to track the torque and speed characteristics continuously.
I have "Fluke 433 Three-phase Power Quality Analyzer", but I think this wont give torque value. It displays Power output in KW and from that I can calculate torque by using one of the formula.
The stuff which you spoke in the post regarding dynamo meters is new to me. I need to get familiarize with using dynamo meters.
Since now you know what I am looking for, can you recommend a basic (easy to use) dynamo meter which outputs the continuous torque speed values when the motor is loaded externally? I am testing the motor by loading it with a blower fan (2nd order).

Thanks a lot
Uday

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parabellum
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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by parabellum » Tue Sep 12, 2017 2:32 pm

e-vektor wrote:Yes, during the first tests with the star topology I got 15HP at 55V (Pb battery), and recently 20HP at 85V (LIPO), so for having more power you either need more voltage (which makes the inverter more expensive) or you need a lower voltage motor (then you need more current to get the same torque).

Keep in mind that the original nominal voltage is 115 VAC, and it changes to 67 VAC when changing to triangle, then from 67 to 85 V you can get some extra power.

Indeed if I had a 144V inverter I think the motor could be about 60 HP (peak)
So, it means, your efficiency could be even higher in appropriate star configuration, eliminating parasitic recirculating current of delta, right?
Do you plan to keep delta?

udaykishanr
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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by udaykishanr » Wed Sep 13, 2017 1:08 pm

e-vektor wrote:300A is ok for this motor but 24V is very low as its nominal voltage in star topology is 115V, so you are always working in the field weakening area, because over 400 or 500 rpm the voltage cannot be increased
V/F is not a good method for traction because it cannot change the voltage fast enough to adapt itself to the changes on load. If you need to climb an incline it will quickly reach to some "short-circuit" as voltage will be too high for current speed. The preferred control method is vector because voltage can change very fast to keep current constant.
Although if you load is constant (like the fans you mention) it may be ok

for measuring torque you need a dynamometer, but as soon as you put some load on the motor the V/F method will reach an overcurrent condition.
Basic dynos are: inertial: just put a steel mass that makes the acceleration slower (weight or inertia have to be calculated to the actual rpm, OR the rpm has to be changed in the flywheel to provide higher load to this high torque motor). You could use an inertial kit, which only needs the flywheel speed (if you need more info please send me a PM)
But preferred dynos are braked because you can also control the amount of load (slow ramps or fast ramps), and also you can create a stationary load, for instance to see the evolution of the inverter algorithms with time. For this dyno you will need an eddy current brake and a braked electronic kit with a load cell, a brake power supply, etc
Both are relatively expensive, first one can cost from 1500 eur (there are also cheaper DAqs but I didn't test it), and braked can cost 6000 eur or more (only the brake can cost 2500 eur or more)
As dyno have become popular, there is some used parts in the market
Thanks for the info.
Well, I designed a circuit board which linearly increases the frequency of the inverter which in turn relates to frequency of the motor.
The ramping up of the frequency in a linear manner causes the motor to follow the "Family of Torque Speed Curves", in which the peak torque is maintained to certain extent. After that if the motor doesn't have enough supporting voltage, the rotor will fall out of synchronism.

Yeah, I understand that 24V battery is very low, but I am restricted to this, since it is intended to go on a airplane where it is supposed to operate no greater than 24V DC.

I need to dig more into what you suggested, the vector control method and also have to do some research on Dynamometers.
By the way I came to know that one of my friends has an AW DynoPro 2100S, but he didnt used it for the past ten years.
So have to get a manual for it and should get acquaint with how to use it.
Is there something called torque meter which sits or attaches to the rotor shaft to give instantaneous torque values?

Thanks
Uday

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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by e-vektor » Fri Sep 15, 2017 10:07 am

Torque sensors are normally extremelly expensive (10K or more), for this reason dynamometers use either inertial load (weight) or load cell for brake (load cell price $70 to $150 normally)
udaykishanr wrote:
e-vektor wrote:300A is ok for this motor but 24V is very low as its nominal voltage in star topology is 115V, so you are always working in the field
weakening area, because over 400 or 500 rpm the voltage cannot be increased
V/F is not a good method for traction because it cannot change the voltage fast enough to adapt itself to the changes on load. If you need to climb an incline it will quickly reach to some "short-circuit" as voltage will be too high for current speed. The preferred control method is vector because voltage can change very fast to keep current constant.
Although if you load is constant (like the fans you mention) it may be ok

for measuring torque you need a dynamometer, but as soon as you put some load on the motor the V/F method will reach an overcurrent condition.
Basic dynos are: inertial: just put a steel mass that makes the acceleration slower (weight or inertia have to be calculated to the actual rpm, OR the rpm has to be changed in the flywheel to provide higher load to this high torque motor). You could use an inertial kit, which only needs the flywheel speed (if you need more info please send me a PM)
But preferred dynos are braked because you can also control the amount of load (slow ramps or fast ramps), and also you can create a stationary load, for instance to see the evolution of the inverter algorithms with time. For this dyno you will need an eddy current brake and a braked electronic kit with a load cell, a brake power supply, etc
Both are relatively expensive, first one can cost from 1500 eur (there are also cheaper DAqs but I didn't test it), and braked can cost 6000 eur or more (only the brake can cost 2500 eur or more)
As dyno have become popular, there is some used parts in the market
Thanks for the info.
Well, I designed a circuit board which linearly increases the frequency of the inverter which in turn relates to frequency of the motor.
The ramping up of the frequency in a linear manner causes the motor to follow the "Family of Torque Speed Curves", in which the peak torque is maintained to certain extent. After that if the motor doesn't have enough supporting voltage, the rotor will fall out of synchronism.

Yeah, I understand that 24V battery is very low, but I am restricted to this, since it is intended to go on a airplane where it is supposed to operate no greater than 24V DC.

I need to dig more into what you suggested, the vector control method and also have to do some research on Dynamometers.
By the way I came to know that one of my friends has an AW DynoPro 2100S, but he didnt used it for the past ten years.
So have to get a manual for it and should get acquaint with how to use it.
Is there something called torque meter which sits or attaches to the rotor shaft to give instantaneous torque values?

Thanks
Uday

ChazFisher
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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by ChazFisher » Sun Oct 29, 2017 10:00 pm

e-vektor - Did you take any AC current measurements for the dyno run that you posted?

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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by e-vektor » Sat Nov 04, 2017 8:14 pm

ChazFisher wrote:e-vektor - Did you take any AC current measurements for the dyno run that you posted?
no, but they are suposed to be controlled by the Curtis and limited to 550A (triangle), which is equivalent to 323A in star.
Indeed the Curtis controller can do a log at 100 ms rate, but current is flat. Also stator frequency can be seen in this log.

If you refer to phase angles, I cannot measure them

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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by electro wrks » Sun Nov 05, 2017 12:35 pm

What's the latest on this motor hack attempt. Were you able to get the motor up and running? I'd be interested in the potential overheating issues with the high power levels you were reaching. Great work, by the way!

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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by e-vektor » Sun Nov 05, 2017 3:09 pm

electro wrks wrote:What's the latest on this motor hack attempt. Were you able to get the motor up and running? I'd be interested in the potential overheating issues with the high power levels you were reaching. Great work, by the way!
The motor is working extremely good in the delta configuration with the 550 A Inverter (38 HP config), you can see my e-kart project here:
Of course with the +50% current usage the efficiency decreases (up to 65% in worst case) and heat increases. Radiator and water pump are mandatory, but the good news is that the kart is not working all the time at full throttle, indeed the rider told me that he cannot deliver full throttle in any corner, only the straight part.

https://www.youtube.com/watch?v=V-M_RFaY3aM


but in the WYE config + 350A inverter (E-ATV project), there is a noticeable lack of power when the field weakening region starts (over 40 km/h). I need to do more tests with the 350A inverter to try to compensate this lack of power, although ATVs normally do not normally need high speeds, but climbing ability. I finally got 105 N*m and 180 kg thrust, which is quite good for a 170 kg ATV (without driver)

https://youtu.be/v2-YZYIgjlU

Nevertheless, with the Delta+550A inverter (e-kart) I have no problems in the field weakening section because it happens from 100 to 120 km/h, and most kartings have short sections, so I don't think I reach 100 km/h, unless I go to a specific big karting

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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by ChazFisher » Sun Nov 05, 2017 3:35 pm

e-vektor wrote:
ChazFisher wrote:e-vektor - Did you take any AC current measurements for the dyno run that you posted?
no, but they are suposed to be controlled by the Curtis and limited to 550A (triangle), which is equivalent to 323A in star.
Indeed the Curtis controller can do a log at 100 ms rate, but current is flat. Also stator frequency can be seen in this log.

If you refer to phase angles, I cannot measure them
OK, thanks. I've been trying to find a hybrid car power stage to recycle, in keeping with the theme of re-purposing parts. :) I'm having trouble finding anything simple that is rated for anywhere near that power level. To get a current rating near the 550A, I have to go to something like a full hybrid car (Chevy Volt, etc.) inverter.

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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by electro wrks » Sun Nov 05, 2017 9:09 pm

e-vektor wrote: The motor is working extremely good in the delta configuration with the 550 A Inverter (38 HP config), you can see my e-kart project here:
Of course with the +50% current usage the efficiency decreases (up to 65% in worst case) and heat increases. Radiator and water pump are mandatory, but the good news is that the kart is not working all the time at full throttle, indeed the rider told me that he cannot deliver full throttle in any corner, only the straight part.

https://www.youtube.com/watch?v=V-M_RFaY3aM


but in the WYE config + 350A inverter (E-ATV project), there is a noticeable lack of power when the field weakening region starts (over 40 km/h). I need to do more tests with the 350A inverter to try to compensate this lack of power, although ATVs normally do not normally need high speeds, but climbing ability. I finally got 105 N*m and 180 kg thrust, which is quite good for a 170 kg ATV (without driver)

https://youtu.be/v2-YZYIgjlU

Nevertheless, with the Delta+550A inverter (e-kart) I have no problems in the field weakening section because it happens from 100 to 120 km/h, and most kartings have short sections, so I don't think I reach 100 km/h, unless I go to a specific big karting
Thank you for your response. If you have the cooling system set-up (radiator, hoses, pumps,etc.), could you post some photos of it so we can get some idea of what would be needed? Also, could you post a simple spread sheet of the controllers(model, voltage, and current rating) you're using ( one's a Curtis12??-???? and the other-?) on the vertical axis. On the horizontal axis, the Delta or Y configuration, the voltage used, ~current range, ~RPM range, power output, and other info that you think might be useful. I know most of this info is in your posts and graphs, but it would be very useful to have it laid out in this form.

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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by e-vektor » Thu Nov 09, 2017 4:24 am

Radiator from an Enduro bike (1 out of 2 radiators in the original bike):

Image

Water pump 12V, from ebay:

Image

motor hoses:

Image


E-KART configuration:
Motor: Buick Lacrosse 2012 e-assist, modified to triangle (66 VAC)
Inverter: Curtis 1238-6501, 80V, 550A (max 105 Vdc)
Battery: 12 x Lipo 22.2V (24S x 3P), 16 Ah, 10C (160A / x3 = 480A), total 96V full charged / 81,6V dead, 4.2 WKh. No BMS at the moment (charged with sepparated LIPO chargers)
Performance: 38 HP, 100 N*m (115 kg thrust), max RPM 4000 RPM (limited by inverter)

e-ATV configuration:
Motor: Buick Lacrosse 2012 e-assist, UN modified (115 VAC)
Inverter: Curtis 1236-6421, 80V, 350A (max 105 Vdc)
Battery: same
Performance: 20.5 HP, 105 N*m (188 kg thrust), max RPM 4000 RPM


electro wrks wrote:
e-vektor wrote: The motor is working extremely good in the delta configuration with the 550 A Inverter (38 HP config), you can see my e-kart project here:
Of course with the +50% current usage the efficiency decreases (up to 65% in worst case) and heat increases. Radiator and water pump are mandatory, but the good news is that the kart is not working all the time at full throttle, indeed the rider told me that he cannot deliver full throttle in any corner, only the straight part.

https://www.youtube.com/watch?v=V-M_RFaY3aM


but in the WYE config + 350A inverter (E-ATV project), there is a noticeable lack of power when the field weakening region starts (over 40 km/h). I need to do more tests with the 350A inverter to try to compensate this lack of power, although ATVs normally do not normally need high speeds, but climbing ability. I finally got 105 N*m and 180 kg thrust, which is quite good for a 170 kg ATV (without driver)

https://youtu.be/v2-YZYIgjlU

Nevertheless, with the Delta+550A inverter (e-kart) I have no problems in the field weakening section because it happens from 100 to 120 km/h, and most kartings have short sections, so I don't think I reach 100 km/h, unless I go to a specific big karting
Thank you for your response. If you have the cooling system set-up (radiator, hoses, pumps,etc.), could you post some photos of it so we can get some idea of what would be needed? Also, could you post a simple spread sheet of the controllers(model, voltage, and current rating) you're using ( one's a Curtis12??-???? and the other-?) on the vertical axis. On the horizontal axis, the Delta or Y configuration, the voltage used, ~current range, ~RPM range, power output, and other info that you think might be useful. I know most of this info is in your posts and graphs, but it would be very useful to have it laid out in this form.

electro wrks
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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by electro wrks » Thu Nov 09, 2017 3:55 pm

Thank you, Great stuff! Is the 4000rpm limit because of the 300Hz stator frequency limit of the controllers? In higher voltage applications, assuming iron losses are not too big a factor, this could be a problem with this 8 pole motor. Does anyone know if other controllers have higher stator frequency limits?

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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by e-vektor » Sat Nov 11, 2017 9:53 am

electro wrks wrote:Thank you, Great stuff! Is the 4000rpm limit because of the 300Hz stator frequency limit of the controllers? In higher voltage applications, assuming iron losses are not too big a factor, this could be a problem with this 8 pole motor. Does anyone know if other controllers have higher stator frequency limits?
yes, 300 Hz is a big limit for this motor, but also in the WYE configuration it has the base freq. at 1000 RPM, and in the Delta config at about 2200 RPM, so even if you increase the stator freq it will still have very low torque.
In my opinion this motor is good for light applications (up to 38 HP very stressed), but it would need higher voltage and freq to be a great motor. For instance between 250 and 300V it may reach 100 HP at 9000 RPM... but at this voltage it does not seem practical for motorcycle and light applications

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Re: Buick Lacrosse 2012 e-assist moto-alternator

Post by electro wrks » Tue Nov 21, 2017 10:10 pm

I would think the iron losses and loss of efficiency would be unacceptably high at those high of voltages. I saw somewhere a Sevcon Gen 4 G9930 controller rated at 300A peak, 120A continuous, 150V max, 500Hz max stator frequency. By my calcs., this potentially could give a max 7,500RPM. In the motor's original application, with an ICE, it looks like it turns a max of 8,000 to 10,000RPM( around 2X crankshaft RPM). So, it should be able to safely handle the 7500RPM. Has anybody tried this controller with this motor? I know the Sevcons have a reputation of being difficult and expensive to set-up.

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