144Vdc EV Charger

Electric Motors and Controllers
User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Re: 144Vdc EV Charger

Post by HighHopes » Oct 30, 2015 4:37 pm

It's for a 144V pack in the 10 to 30kWh range.
I put that profile on there just to sort of show what is expected of the hardware design and why. It's basically just a generic profile. The actual profile hasn't been determined yet but I suspect it will look similar in the end. It's all software programmable so you can change it as you need

as an aside, my preferred method of energizing a battery is to apply 1000V microsecond pulses of potential (voltage without a ground reference) at the resonant frequency with ideally 0 amps. .. but that's a story for another day 8)
Last edited by HighHopes on Nov 07, 2015 9:23 am, edited 1 time in total.

zombiess
1 GW
1 GW
Posts: 3294
Joined: Feb 01, 2011 2:16 am
Location: Ventura

Re: 144Vdc EV Charger

Post by zombiess » Oct 31, 2015 10:52 pm

HighHopes wrote: as an aside, my preferred method of energizing a battery is to apply 1000V microsecond pulses of potential (voltage without a ground reference) at the resonant frequency with ideally 0 amps. .. but that's a story for another day 8)
Does it work on non Jedi brand batteries?

zombiess
1 GW
1 GW
Posts: 3294
Joined: Feb 01, 2011 2:16 am
Location: Ventura

Re: 144Vdc EV Charger

Post by zombiess » Oct 31, 2015 10:54 pm

HighHopes wrote:hmm.. how come some attached jpg image show in the post and some are click to view?
Resize to 800x600 and they will show up, it's always worked for me.

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Re: 144Vdc EV Charger

Post by HighHopes » Nov 01, 2015 11:18 am

zombiess wrote:Does it work on non Jedi brand batteries?
any kind, but if Li-ion or its variant you have to remove BMS. also works on non-rechargables. it was developed over 30 years by one guy, its not my concept or patent. i just got interested and made my own for interest's sake and satisfied myself it really does work. there's only two textbooks in which the concepts are described mathematically; Maxwell's electrical treatise volume 1 & 2 (not volume 3) and Dr.Myron Evans book (but this takes post-doctoral degree in mathematics to understand).

ps. re-size image worked, thx.

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

things that make you go hmmmm....

Post by HighHopes » Nov 05, 2015 10:59 pm

here's something i've been thinking of:

let's say i put this charger in my EV. so techncailly i can plug my car into any regular 240V, 30A receptical. i do not need an EV wall-box as the charger is internal to the car. but what happens if i plug into a receptical that is only 15A rated? how will my charger know not to charge at its normal 30A rate?

ha.. after so many days of thinking, i type this out and the answer comes to me. i would be using my own cord. my own cord has 30A plug on it, and it will definitely not fit into a 15A receptical cause they are keyed differently. if i whipped out my 15A cord to fit the receptical i should press the 15A charge rate button that is near the "gas tank"?

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Re: 144Vdc EV Charger

Post by HighHopes » Nov 07, 2015 9:29 am

let's say you plug in to 115V receptacle. how does the controller know if it is 15A rated or 20A? such a receptical is supposed to be T-slot but i don't know if that is a north american wide standard or not and also i think its unreasonable for everyone to know that anyway. so the controller has to decide for you. knowing input is 115V not 240V is obvious to controller. but .. 15A or 20A? i guess you have to assume 15A (which is actually only 13A on the input side else you risk tripping the breaker). but 1.5kW, that is not so bad. you could say this is charge over night possible for a lightweight small EV. the charger though is more efficient at 240V, so that's the preffered input.

if you installed this charger in a car, you could say it is dual mode. 115V, 15A level-1 charger or 240V, 30A level-2 charger. i'd be happy with that!

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Re: 144Vdc EV Charger

Post by HighHopes » Nov 07, 2015 9:34 am

@software guy. i'm leaning towardsTMS320F28069PFPQ DSP. actually for sure that unless we find some reason it can not be. no reason to start software development yet, wait for PCB layout to begin and THEN it willl be time to start software design.

i'm still cleaning up the schematic and then will start the magnetics design.

for the control power supply.. idea comes to me.. the one for the EV charger is nearly the same as the one for the EV controller. the EV controller is slightly more advanced. but now i think.. for like $5 more in parts they can be both the same. i think there is a lot of value in this approach. hmm.. i will rethink the control power supply for EV charger and perhaps revise it. hmm.. more ideas are coming to me. during operation, driving around, its possible then that the on-board EV charger (which is not in use at this time) could have it's EV charger control power supply act as a backup to the EV controller's power supply. especially if they are 100% the same design & power rating. you see.. more value. add also a regular car battery and you now have dual redundant power supply :)
Last edited by HighHopes on Nov 07, 2015 4:30 pm, edited 1 time in total.

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Re: 144Vdc EV Charger

Post by HighHopes » Nov 07, 2015 12:12 pm

what if you planned from the beginning to make the EV charger & EV controller ONE unit? they could share certain resources. clever use of contactors.. since only one is running when the other is turned OFF .. hmm....

zombiess
1 GW
1 GW
Posts: 3294
Joined: Feb 01, 2011 2:16 am
Location: Ventura

Re: 144Vdc EV Charger

Post by zombiess » Nov 07, 2015 1:43 pm

Maybe monitor voltage sag of the AC line as the charger increases current. Not sure if this could work, just an idea.

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Failure Modes

Post by HighHopes » Nov 07, 2015 8:05 pm

Taken from point of view that charger is installed in the rather than wall mount. So.. what type of failure modes are there for charging a large traction pack? anyone got a handy list?
Mode1: OFF - Not in use
In this mode the charger is not in use,the AC cable is not plugged in. the car can be in motion or not. With no AC cable plugged in there is no power to energize the control power transformer.

Mode2: ON - Standby
In this mode the AC cord has been plugged in but charging battery has not started yet.

Mode3: ON - Charging
In this mode the EV charger has started the charge cycle.

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Re: Failure Modes

Post by HighHopes » Nov 14, 2015 3:12 pm

failure mode and effects analysis (FMEA) is part of the design assurance process. its normally done in one of two ways, at the functional block or component by component. then you have to ask your self the following questions what happens if this function fails High? fails low? fails indeterminate? each of the failures, well it would be nice, if there was a designed in solution or at least can be determined to be inconsequential.

we'll just stay at the abstract level (higher than functional block and much higher than component by component) and look at the actual charge failure mode. real simple, EV Charger fails. so what does this mean? think of it as fails high, fails low, fails indeterminate.

fails high, we can say that maybe this means the constant current never ramps down it just charges at full out rate (for who knows what reason). so, what would happen? well, we have current sensor that should detect that the output current is not following the profile and should do..what? initiate a failsafe? this implies we need a failsafe routing in the software (go to this mode if a problem is detected). should the problem be logged? should an LED flash? should a heads-up display indicate? you can also say that the BMS should indicate that battery is fully charged and we expect BMS to give "fully charged" signal back to the controller.. and you might think..what if the full out charge rate is because DSP failure? so the BMS has to be like a backup.. you know, BMS says "battery is all charged so stop the damned charging!" but charger doesn't stop should there be a hardware shutdown based on BMS feedback because this is a crtical failure? maybe.. we have to think also that we deal with only ONE failure at a time. you can design for double failure but it gets real expensive/complex real fast and usually single failure analysis is sufficient. so charger don't stop charging, this could be mitigated by DSP detects profile not being followed and shuts down (here we are assuming taht the problem is with hardware) what's the likely hood that problem is wilth hardware, a problem where current keeps charging? i think the failure would have to be in the current sensor or feedback which would fool the DSP into thinking the current is a value different than it really is.

anyway.. this all gets mapped out. usually not so convoluted as the above .. and you identify which failures are critical and for sure design a shutdown protection, which failures are not critical and is nice to design a solution for these or at least identify that the failure is not a big deal. like charger fails to charge ( fails low). is this a big deal? not really.. just is annoying the next morning when you want to go driving around and you can't.

charger fails indeterminate? not sure what this means... umm.. charger is fine but can not detect the battery so it never starts?

anyway, its a good exercise to go through for design assurance. also helps put a system wide picture in your mind.

peters
100 W
100 W
Posts: 249
Joined: Oct 20, 2012 11:46 pm
Location: Budapest, Hungary

Re: 144Vdc EV Charger

Post by peters » Nov 14, 2015 5:31 pm

When I did FMEAs we classified the failure modes into a few groups: first is board I/O failures, second is internal hardware failures (functional blocks which has no direct I/O connections, typically on-board power supplies), third is software function failures. Then the root cause of the failure in the first group is usually a component failure, the detection is typically feedbacks from the I/O lines and the compensation can be redundant signal paths. For the second the detection is the on-board measurement of the signals by software or supervisor circuits (for power supplies), and for software failures it can be recurring action or communication or an external watchdog circuit or a supervisor PLD for the critical functions. Another typical detection for I/O errors was to drive the signals by square waves instead of a constant voltage, then the stuck at high or low failures can be detected immediately in runtime... just some examples, the list was long and every circuit is different. Power-on test was executed by software which included on-board testing of power supplies, I/O test by on-off switching all signals, testing the redundant lines, communication test with other boards, etc... High level compensation was to shut down the system or continue in degraded mode or disable the related function and indicate the failure to the user. Permanent and intermittent failures were also differentiated, and sometimes it was allowed to restore the function after the failure disappeared, sometimes not.

Jumping to e-vehicles, recently I had an issue with a bad BMS connector and one cell was charged to 3.8V and the one nearby to 3.4V instead of 3.6V. If I would follow the guidelines I should double the whole BMS circuit and detect discrepancy between the 2 modules, because the cell voltage measurement is critical. Charge current measurement is also critical which would require redundant sensors, and the same for cutting off the charger from the battery.

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

FMEA

Post by HighHopes » Nov 15, 2015 10:13 pm

yes exactly! you are talking about the functional block level and sounds like you know exactly what you're talking about. do you want to take on the control power supply FMEA?

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Interface

Post by HighHopes » Nov 15, 2015 10:22 pm

i did a quick & dirty 8-wire to 20x40 LCD interface and then i deleted it. i think i have to decide is this charger going to be IN the car? or wall mount? ok.. i pick.. IN the car. so.. now i deleted the LCD interface and will have comms over to the main EV controller instead and the heads up display in the car.

the charge status will appear on the car's heads up dispaly (if key in ignition, car won't start while being charged but the aux. power will be available so the heads up display will light up).

the other interface, maybe some LEDs around the "gas" cap. some yellow and green to show state of charge and a blinky RED to show if there is some error. this can be a simple SPI interface from EV Charger to gas cap LED board. or maybe CAN bus? i don't know communication protocol very well, is something i need to learn more about.

maybe even a wi-fi interface??? so you can open an APP on your smartphone to see charge status and can disable or whatever from your phone.. hmm. i'm getting ahead of myself. version 1.. stick to the basics :)

as an aside, another reason for in-car charger, is because i would like to progress to wireless charging in some future revision. and then from wireless charging (using herztian waves) to something using longitudinal waves (reminiscent of fancy battery energizer i mentioned briefly couple posts back). for both of these you'll need a charger on board anyway.

peters
100 W
100 W
Posts: 249
Joined: Oct 20, 2012 11:46 pm
Location: Budapest, Hungary

Re: FMEA

Post by peters » Nov 16, 2015 6:54 am

HighHopes wrote:do you want to take on the control power supply FMEA?
Thanks for the offer, but I have no free time and brain resource besides my projects (bike controller, display, bms, bootloaders, firmwares, new frame... should live for 1200 years to complete everything ;) )

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Re: 144Vdc EV Charger

Post by HighHopes » Nov 23, 2015 6:29 pm

i have a slight change of heart.. i am no longer going to put the charger inside the car. why add the weight? it will be wall mount. i want to gear my EV controllers to high performance drives and in that world, weight matters.

peters
100 W
100 W
Posts: 249
Joined: Oct 20, 2012 11:46 pm
Location: Budapest, Hungary

Re: 144Vdc EV Charger

Post by peters » Nov 24, 2015 1:53 am

For me I'm planning to put the charger in my bike because then I don't need to carry the charger in a backpack when I go on a longer trip. This would be in my next-next project so I keep an eye on your design anyway.
How much do you think a 2kW charger would weight? HF transformer, coils, heatsink...

In my current controller I'm experimenting with the charging method similar to Adaptto's (charger = regular DC power supply + the controller working as a boost converter), but using the hub motor as the inductor instead of an external coil, and going to start a topic when I have something working to show.

User avatar
liveforphysics
100 GW
100 GW
Posts: 14483
Joined: Oct 29, 2008 1:48 am
Location: Santa Cruz, CA, USA

Re: 144Vdc EV Charger

Post by liveforphysics » Nov 24, 2015 2:28 pm

HighHopes wrote:i have a slight change of heart.. i am no longer going to put the charger inside the car. why add the weight? it will be wall mount. i want to gear my EV controllers to high performance drives and in that world, weight matters.

Saves yourself a lot of weatherproofing related and thermal path related challenges with doing a vehicle robust packaging design over an open frame fan cooled system that is garage friendly.
Each carcinogen vapor exposure includes a dice roll for cancer.

Each mutagen vapor exposure includes a dice roll for reproductive genetic defects in your children.

Each engine start sprays them into a shared atmosphere which includes beings not offered an opportunity to consent accepting these cancer experiences and defective genetics life experiences.

Every post is a free gift to the collective of minds composing the living bleeding edge of LEV development on our spaceship.

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Re: 144Vdc EV Charger

Post by HighHopes » Nov 25, 2015 6:03 pm

peters, for your application you can probably get away with a non-isolated solution to save weight. this is also called a "single stage" charger. in this topology you would use your battery as the charger's output capacitors.. so you save volume by not having caps.

of course the ripple current into the battery goes up so you have wear/tear but you can see that most battery chargers out there offer this solution and they do not tell their customers that their solution will wear out their batteries (battery heat while charging = bad).

as for estimate of weight, its hard to say as it depends a lot on your switching frequency, allowable specs for ripple and thermal management.

User avatar
liveforphysics
100 GW
100 GW
Posts: 14483
Joined: Oct 29, 2008 1:48 am
Location: Santa Cruz, CA, USA

Re: 144Vdc EV Charger

Post by liveforphysics » Nov 25, 2015 6:18 pm

HighHopes wrote:peters, for your application you can probably get away with a non-isolated solution to save weight. this is also called a "single stage" charger. in this topology you would use your battery as the charger's output capacitors.. so you save volume by not having caps.

of course the ripple current into the battery goes up so you have wear/tear but you can see that most battery chargers out there offer this solution and they do not tell their customers that their solution will wear out their batteries (battery heat while charging = bad).

as for estimate of weight, its hard to say as it depends a lot on your switching frequency, allowable specs for ripple and thermal management.

It's amazing how many cycling tests show high frequency ripple current causing ever so slight improvements in cell cycle life. Not substantial enough to be worth making something special to do it, but typically worth a few percent longer cell life.

The cells charge rate is ionic diffusion rate limited, having some ripple in the mechanism driving diffusion gradients seems to help it just a whisker over pure clean DC for charging (which I agree would result in the coolest temp cell).
Each carcinogen vapor exposure includes a dice roll for cancer.

Each mutagen vapor exposure includes a dice roll for reproductive genetic defects in your children.

Each engine start sprays them into a shared atmosphere which includes beings not offered an opportunity to consent accepting these cancer experiences and defective genetics life experiences.

Every post is a free gift to the collective of minds composing the living bleeding edge of LEV development on our spaceship.

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Re: 144Vdc EV Charger

Post by HighHopes » Nov 26, 2015 6:00 pm

i'm talking about a single stage charger having a low frequency output ripple current that is 10-20%. i think you are talking something much smaller and higher frequency, perhaps switching frequency ripple?
Last edited by HighHopes on Nov 28, 2015 1:07 pm, edited 2 times in total.

peters
100 W
100 W
Posts: 249
Joined: Oct 20, 2012 11:46 pm
Location: Budapest, Hungary

Re: 144Vdc EV Charger

Post by peters » Nov 27, 2015 12:17 am

And that ripple frequency is the PWM or the mains 50-60Hz? Not sure they have the same effect.
In a single stage if there is no energy storage and no PFC then the mains frequency is on the battery, is it true?

User avatar
HighHopes
10 kW
10 kW
Posts: 852
Joined: Mar 28, 2013 6:25 pm

Re: 144Vdc EV Charger

Post by HighHopes » Nov 28, 2015 1:04 pm

obvioulsly you will get both mains & high frequency noise. they do not have the same effects, but they both lead to same end result.. less efficiency faster wear & tear.

for low frequency, it's probably 100Hz/120Hz because your input single phase AC will be rectified. it's possible if you have good and fast current feedback controller you can compensate enough to effectively remove the ripple but you will waste DC link utilization to achieve this (i.e. you need higher DC bus voltage than otherwise required, or, same DC bus but limited range of duty cycle as some portion must always be reserved for ripple elimination purpose and you have to ask yourself do you have enough duty-cycle left over to properly charge the battery).

if you leave the ripple as is, i think this just adds wear & tear on the battery because it generates heat. a lot of wear & tear if you are trying to "fast charge". but i'm not a battery expert, you'd have to ask Luke how to know what the acceptable limits are.

zombiess
1 GW
1 GW
Posts: 3294
Joined: Feb 01, 2011 2:16 am
Location: Ventura

Re: 144Vdc EV Charger

Post by zombiess » Nov 29, 2015 8:40 pm

liveforphysics wrote:
The cells charge rate is ionic diffusion rate limited, having some ripple in the mechanism driving diffusion gradients seems to help it just a whisker over pure clean DC for charging (which I agree would result in the coolest temp cell).
Sorry, going a bit OT here HighHopes.

liveforphysics, Why? Does the ripple excite some sort of natural resonance? Do batteries form charge domains similar to the way magnetic materials form magnetic domains?

User avatar
liveforphysics
100 GW
100 GW
Posts: 14483
Joined: Oct 29, 2008 1:48 am
Location: Santa Cruz, CA, USA

Re: 144Vdc EV Charger

Post by liveforphysics » Nov 29, 2015 9:19 pm

zombiess wrote:
liveforphysics wrote:
The cells charge rate is ionic diffusion rate limited, having some ripple in the mechanism driving diffusion gradients seems to help it just a whisker over pure clean DC for charging (which I agree would result in the coolest temp cell).
Sorry, going a bit OT here HighHopes.

liveforphysics, Why? Does the ripple excite some sort of natural resonance? Do batteries form charge domains similar to the way magnetic materials form magnetic domains?
My guess is that the linear roughly static DC field results in a slighly reduced rate of thermo-kinetic collisions between ions and solvent than having ripples in the field to perhaps encourage ion motion and intercalation through whatever mechanisms. (Aka, I dont know)

The tests were something like 50% ripple at 20kHz, and it does cause every so slightly more cell heating during charging, yet also extended cycle life by a couple percent.

Ive never seen a test with Lithium that seemed worth the hassles of doing it, but for some Nickel based cells its meaningful enough of a performance boost to be worth doing.
Each carcinogen vapor exposure includes a dice roll for cancer.

Each mutagen vapor exposure includes a dice roll for reproductive genetic defects in your children.

Each engine start sprays them into a shared atmosphere which includes beings not offered an opportunity to consent accepting these cancer experiences and defective genetics life experiences.

Every post is a free gift to the collective of minds composing the living bleeding edge of LEV development on our spaceship.

Post Reply