|
When we last discussed motor control on this blog, EP10 was drifting around on the frozen lake in Arvidsjaur, Sweden. At that time (January 2007), we were in the process of co-evaluating Conti-Teves’ ABS system in tandem with Tesla’s motor control. We left the lake thinking highly of the Conti system and moderately pleased with the Roadster’s motor control and traction control algorithms.
Greg pointing happily to the DMC
spinning a motor for the first time.
Meanwhile, back in San Carlos, we were mulling over a number of slight imperfections with our motor controller. In a variety of transient and highly demanding conditions, the motor control algorithm didn’t perform as well as we would have liked, leading to instability and even control faults (equivalent to ICE misfires or stalls). Our favorite driver, Phil Luk, could sometimes trick the controller into instability with one or two quick flicks of his foot. Sudden throttle lunges were not unheard of, and drivers generally needed to learn the subtleties of driving without introducing oscillation.
Early investigations implicated component variability and lack of control bandwidth as issues inherent in what we refer to now as the analog controller’s design. JB Straubel, Tesla’s CTO, was wary of shortcomings with analog control from Tesla’s inception. By the time EP10 was on the frozen lake, he had tasked a team of 4 Tesla engineers, including myself, with producing a competing design—a digital motor controller (DMC)—to hopefully replace our existing technology.
Colin and I enjoy our first
DMC drive in EP1
Everything began in November 2006—whiteboard design sessions, in-depth brainstorms with friends in academia and industry, round table discussions of needed improvements—and our first deadline was to spin a motor by the new year. A month of long days and some head scratching later, we met our deadline 10 days ahead of schedule. The months of January and February were a blur of hours of dynamometer time and the unique squeal of “digital” torque. I remember the first time I played with DMC transient response; stable full torque reversals at high speed and under load could be heard throughout the San Carlos warehouse. People would come up to me remarking at the racket and noting they could always tell when I was running the dyno, even through conference room walls!
Our reward for hard work came in March of 2007, when Troy, Greg, Colin and I enjoyed a DMC weekend crowned by 200 mile maiden voyages in EP1 and VP1! Luckily, Tesla’s marketing staff had scheduled a photoshoot for that weekend, so we drove away from 1050 Bing in style with cameras in tow. The only problem with the vehicles all weekend was with EP1’s transmission – a harbinger of things to come?
The team (minus Greg) pose while troubleshooting
the new controller in a parking lot.
Finally, after six months of full-time effort, JB’s concept of a digital signal processor (DSP)-powered motor and charge controller in the PEM was a reality. In June of 2007, Tesla executives decided to make the DMC the plan of record for all future PEMs. Prior to that decision, the DMC had been put through its paces and performed extremely well for a number of reasons.
Most importantly, in the DMC, the motor control technique we employ is stator flux-oriented vector control. Vector control is complicated mathematically (thus our need for a 150MHz DSP), but it allows us to directly control magnetic flux density and torque as DC quantities. The former analog system controlled AC current frequency and magnitude, a much simpler task from a programming standpoint (an 8bit PIC can hack it), but much more difficult to get right from a stability perspective and generally lower performance.
Troy and I drive VP1 and EP1 north on 101
in spitting distance of the photography van.
Right after this photo I totally burned the trailing Porsche.
When all was said and done, the new controller gains in a number of key areas. We improved motor peak torque by up to 5%, stability across the operating envelope, and transient response by leaps and bounds, all while maintaining or increasing efficiency, gaining flexibility and repeatability of key user interface characteristics (regenerative braking, throttle response, pedal scheduling), and adding in-depth diagnostics and fault-handling. Overall, we took a giant step forward in the robustness of the PEM, the brain or heart (depending on your perspective ) of the Tesla drive-train. The project was incredibly fun to be a part of, and a fine example of Tesla’s engineering intensity and rigor at work.
Posted in the categories: Power Electronics
Ahhhh 35 long days………….
Go Tesla Go!!!!!!!!
Thanks Drew for the insight into your work upgrading the brain of the roadster. Definitely sounds like changing to the DMC was the right choice to solve the stability problems and get some performance improvements. Have other production units made it out of customs yet?
Philip
Clearly, you understand how to use vector control to handle motor output. It is too bad that you couldn’t bring that experience to resolve the 2 speed transmission problem. If the gear ratio between first and second was simply to large for a motor capable of 13,000 RPM, could you have achieved success with a 3, 4 or 5 speed transmission, using vector control algorithms?
If you want to keep the Tesla Roadster as the premium performance EV on the market, you should press forward on a multi-speed transmission development.
Was digital motor control used in any previous production electric vehicles? (like the EV1, Honda EV+, Rav4 EV ect.)
I wish Tesla could explain to us the basics of their controller. Unfortunately, It would all just be Greek to me, so I guess there really wouldn’t be any purpose!
>> We improved … transient response by leaps and bounds
Can anyone explain in simple words what this really mean? Thank you
I remember when the previous torque curve was replaced with much more linear and a little higher one (the current one). It was mentioned that progress was due to using more IGBTs. I guess now we learned the more substantial reason for that improvement
Will the DMC offer drivers selectable profiles so that they can tailor the car to their preference (more regen, less, regen only w/ braking, etc)? How about Open Source firmware for the Roadster
The series of circuits in the zip file in the following link will show you how to convert 30 Watts to 13KW without using more than the 30 Watts from the Battery. The circuit as a rule cannot be directly loaded by a changing load. But, that does not prevent you from generating electricity.
elgersmad.homestead.com/files/Resonance/Proof.zip
If you want to experiment and prototype a few of these circuits the tutorial to construct your own is here:
elgersmad.homestead.com/files/Resonance/ChaosI.html
If you would like details on how it works. Basically, when the Q factor of a parallel resonant circuit is at work with a step up transformer. There is Q in, and Q out, or Q primary and Q secondary of the resonant circuit. Using a capacitive current doubler will half the voltage and double the current. So, if the input impedance of 10 volts is 100 ohms, you would have 100mA of current. Place a capacitor in parallel with the voltage, and a resistance of 25 ohms to ground, you’ll measure 200mA of current at 5 Volts. The Q effects the ring value and the Q represents how many cycles the circuit will produce after a single pulse of energy is applied. For each half cycle, 200 mA can be added until the Voltage is somewhere between 10 and 5 volts, and the current is somewhere between 100 mA and 200 mA. The result is power gain as long as the impedance of the parallel tank circuit isn’t so low that the resonant state doesn’t build a real voltage. So, 1 to 3 is possible, but 1 to Q-10 or Q-20 produces the highest power gain. You won’t believe it until you build it.
If you want more details, or look at a blog that covers more details go to this link:
boards.startrek.com/community/messages.html?s=036b00d67637d7e660bfdebe30f03eb1;act=ST;f=10;t=33309396
Nice work!
errr….thanks James….much clearer now…ha ha
Very clever. Congratulations on getting this new design to the prototype stage. Ready for production in Q4?
AC motor theory stuff (analogue): www.st.com/stonline/products/support/motor/tutorial/motor.swf
www.industrialcontrols.eetchina.com/PDF/2007JUL/ICCOL_2007JUL12_IODR_TA_02.pdf?SOURCES=DOWNLOAD
Drew,
Which DSP did you choose?
I just had someone looking over my shoulder at a photo of the Tesla and mentioned:
- That looks like the canopy on a plane
Then I thought….. that’d be a cool design. If the back window was on a slope along the “trunk” a second canopy could be added that slides forward to provide the roof. In the rain, you slide it forward and lock it in place, in the sun you slide it back locking it in place.
Then I thought - Doh! How does one open the trunk? I guess that idea doesn’t quite work. A couple possible solutions might be
1) Flexible canopy.
2) The canopy must be in the “closed” position for the trunk to open.
Ah well… a good idea for a car without a trunk.
Thanks for describing the exciting technology at the heart (or is it in the brain?
) of the power train. But after all the bracing tech talk, the quote that sticks with me is this: “Right after this photo I totally burned the trailing Porsche.”
That’s what it’s all about, right there. I get such a kick out of watching the Teslans have fun with this amazing toy. I appreciate being allowed to share the fun on these blogs.
Great work! Waw +5%
I know this isn’t quite on topic, but in regards to this article: blog.wired.com/cars/2008/02/wipers-stereo-p.html
Has Tesla come up with solutions for things like that or are the whipers/stereo/whatever still running off the battery?
as a pure battery electric vehicle, all accessories run off the battery. We have developed engineering solutions for accessories that are usually run from the engine mechanically (for example, heating) and have engineered solutions for running some 12V systems from a 400V battery. In reading the Wired article, I get the sense that the author is getting some things wrong since not all of it makes sense to me. -ed.
150Mhz DSP?
That must be freakin’ complex! I don’t know about other automotive embedded chips but this sound quite overkill.
GM put together a presentation to show the relative benefits of various hybrid configurations:
fastlane.gmblogs.com/PDF/presentation-sm.pdf
I am sure you can use this same data for your own range extended vehicle sales. The impact of the 100% BEV on these numbers should be obvious, but some customers may consider the E-REV approach good enough.
Off topic but very interesting Q & A here with Mac Powell of Tesla on the Lotus Engineering site’s newsletter.
www.just-auto.com/proactive/pdf/1a2ss34sw/lotus-newsletter-issue-24.pdf
Chris, that wired article sounds seriously uninformed…this reporter lost all credibility when he said normal cars run the AC off battery power. My favorite part was “but the Volt doesn’t have an alternator…” It doesn’t? How does this 1-liter engine charge the batteries? And this “redundant systems” line doesn’t seem to mean anything at all. All this really means is that GM is having to come up with electric versions of its ordinarily engine-driven accessories, like AC and heat. The fact that the headline mentions wipers and stereo is perplexing…they might be coming up with higher efficiency versions of these, but they really don’t sound like the big issues from either price or range perspective…certainly they won’t be as big a problem as AC. The only part of this that sounds right is the price increase, and that doesn’t seem surprising to me at all.
Roger, the other problem I see with the canopy idea (at least as it relates to the roadster and/or other open-top sports cars) is weight. But that did immediately remind me of the (rather questionably viable) “Skyweb Express” personal rapid transit scheme, which has vehicles with just this sort of sliding canopy…in their case used just for ingress/egress. It does seem more apt for an entrance than a convertable top…after all, that’s what they use it for in aircraft.
James, you can change the power all you want, but you still need the same amount of energy. So if you want 13kW output for a second and you only want to draw 30W from the battery, you’ll have to draw off the battery for at least 7.2 minutes to produce your 1 second of juice.
Jason, your whining is getting feebler. Your contention that Tesla needs to have multiple speeds isn’t backed up at all, and you totally ignore the weight, performance and efficiency penalties that go along with a transmission. If this car meets performance and reliability expectations, who cares how many gears it has?
Drew, this article was great. I’m happy to hear that you had such great success, and that you have broken new ground in motor control. Thanks for the post.
Hunter,
My only point about the transmission, is that it won’t be long before another automaker comes out with a single speed electric vehicle with water cooled motor and high performance ESS to compete with the Tesla Roadster, and one great way to stay a step ahead is to continue development of the 2 speed transmission, or simplify the problem and pursue a 3, 4 or 5 speed transmission, which would give the Roadster a phenominal top speed, given the high torque of an electric motor.
HAVE YOU GUYS SHIPPED ANY CARS YET ?
WHATS THE PRODUCTION TIME LIKE ,?
WHEN WILL YOU BE FULL SPEAK AHEAD
# Hunter wrote on February 13th, 2008 at 12:16 pm
## GM is having to come up with electric versions of its ordinarily engine-driven accessories, like AC and heat.
One would think that they already figured all that out when they built the EV1…
Many existing hybrid cars already have electric driven accessories now like electric power steering and such.
GM has been building fuel cell powered prototypes for ages that all have electric accessories. This is nothing new for them.
Jason and Hunter. Although having a lot of gears on an EV might seem counter-intuitive it does offer one advantage that could make it worthwhile. It reduces the rev drop between the gears that seems to have been a lot of the problem with the Roadster. So, if you had say a 4 gear box but still a relatively low top speed of 135 - 140mph, you should be able to get back to a relatively normal rev drop between gears. Then the problem would be to change gear fast enough to keep up with the car
I think you’d have to have flappy paddles behind the wheel or a sequential box like a motorbike and even then you’d have to be very quick with your changes. You might be forced to go automatic or semi-automatic. This kind of complication would only make sense on an expensive, supercar EV like a Tesla. I’m sure most economy-style EVs in future will just have a reduction box.
Hey Hunter;
With regards weight, I’m sure there’s some ingenous light-weight type clear polymers - or some “reasonable facsimile” thereof. Think along the lines of a soft-plastic, perhaps with a frame to hold it’s form. The only real problem with that is the safety requirements - however, I imagine the only requirements to match would be those of a soft-top for a convertible.
With regards to “that’s what they use it for”, just because something was built for one purpose doesn’t mean it’s not useful for another. I once saw someone drop a looney - Canadian Dollar - into a water-heating vent. There was an outer frame cover over it and the looney landed on the fins. While everyone else was pondering how to get the coin out I noticed the covering had no bottom. I folded a piece of paper into a strip - thereby increasing it’s strength - slipped it through the top gril and pushed the looney till off to the side so it fell off the fins and out the bottom. Voila, problem solved. I doubt the inventor of paper imagined using it as a lever but it made a very useful lever in a pinch
As I understand it, the real headache for the FOUR transmission companies who tried (and failed) to create a gearbox is the lack of a flywheel to even out those sudden changes in torque. Even Ricardo couldn’t solve it in the time available.
Maybe more time and more money will solve the problem, or maybe putting the same money into electric motor systems development will yield the same results with less complexity.
Curiously, after throwing (how much?) money at traditional ICE component manufacturers it would seem that Tesla’s own engineers are the ones who have devised a way to save the Roadster performance specs and Tesla’s reputation.
In the original plan, creating the Roadster would make it easier to design and make Whitestar. In the event, developing Whitestar has helped you to finish the Roadster. Hands up who saw that one coming?
Moral? When your team is trying to do the impossible, be careful who you sack - you clearly don’t know where the solution to your next problem will come from.
I’m sorry but your comment makes no sense. Tesla engineers have always been involved in the development of the powertrain. We have learned a lot over the last few years with regards to transmissions after the failure of our suppliers to achieve successful results. It is great news that we have developed a superior overall solution for the Roadster that leverages our ongoing powertrain development but what does that have to do with your “moral”? We have over 80 people in the powertrain group working hard on Roadster, the sedan and other projects. - ed.
In regard to the 2-speed transmission discussion, I’ve been wondering what the viability of using a motor with multiple windings would be. I’ve seen this before on motors, where it has for example a low-power winding for light work, maybe a medium-power winding for most normal work and and a high-power winding for dealing with unusually high loads. Each winding would be tuned for its intended range of use - the rotor/stator timing, wire gauge and lobe wrap count all could be adjusted as necessary.
This way it seems like you could eliminate the transmission altogether and just control efficiency and power entirely through electronics by changing which winding you are driving. You could provide a switch that chooses between “Manual Transmission” and “Auto Transmission”. It SEEMS like this would be way more efficient than any sort of mechanical transmission because you would eliminate all those moving parts. But I can also imaging that a motor with multiple windings may be prohibitively large and unwieldy. Maybe the trade off between losing the transmission and enlarging the motor would wash?
My understanding of the tranny problem was that the motor’ rotor was acting as too much of a flywheel. Remember, you’ve got a big chunk of copper spinning around on nice bearings (has Tesla ever said how much that rotor weighs, or more important, what it’s rotational inertia is?). You cut fuel to a piston engine and it’ll stop pretty quickly because there is so much friction and compression going on, so it naturally slows down to the lower RPM needed when upshifting. Cut power to an electric motor and it just keeps spinning. You have to use your electronic controls to slow it down, just as if you were doing regenerative braking.
I’m guessing the problem is that in order to slow the rotor down quickly enough for a reasonably fast shift they’d have to apply a pretty hefty amount of torque. All that torque would mean a lot of current flowing, probably more than either the motor or the ESS could deal with. So you either overload your motor/electronics, or you try to engage your gears with the rotor spinning too fast and really slam the tranny/driveshaft/differential/halfshafts. Or the third alternative is you take a few seconds to make a shift, which really sucks when you’re trying to turn a quick quarter mile.
How to fix the problem?
1) Beefing up the motor and electronics to handle the current & torque. Without knowing the rotor’s rotational inertia one can’t estimate how tough this would be, but I’d bet it’s not at all feasible. I’d guess that slowing that rotor down in less than a second would take at least twice the torque they can handle, probably even more. And even a one second shift would feel terribly slow. Next time you drive a manual, hold the clutch in for a full second on every shift and see how it feels.
2) Beefing up the drivetrain to handle shifting with unmatched RPMs. Again, don’t know if it would be possible, but even so, it would will never give a good experience to the people in the car. You can shift a manual transmission ICE without lifting off the gas to get a similar experience. It snaps heads back and chirps the tires in my Miata, which doesn’t have nearly the power of the Tesla. Giving your customers whiplash every time they shift isn’t a good plan.
3) Adding more gears so you have a smaller step. Actually a few smaller steps that add up to just as much time spent slowing the rotor down by the time you get to your top gear. Remember, it’s still going to take longer to slow the rotor that it takes for an ICE to slow down, even with the same sized steps. So a normal 5 speed tranny might still take one second per shift, which means you waste 4 seconds that you could be accelerating before you get to 5th gear. You can spend 4 seconds making one shift, or you can spend 4 seconds (and make the driver work a lot harder) making 4 shifts, but that’s still 4 seconds that you aren’t accelerating.
4) Use a fluid clutch so you don’t have to match RPMs and just waste a bunch of power making hydraulic fluid hot. Not really a good solution for a performance car.
5) Use one medium ratio gear and beef up the motor and electronics to be strong enough to still accelerate as fast as you would have in the old 1st gear, and also be able to spin fast enough to get the same top end as the old 2nd gear. This is apparently what Tesla is doing. I’d say a 50% increase in torque and RPMs should be enough, much more doable than solution #1.
Keith
## ed wrote - I’m sorry but your comment makes no sense.
My bad.
Here on the blogs, we’ve grown used to steady news of success. The transmission problem is the most significant technical wobble we have seen from Tesla in the whole of the Roadster development program. This seems to have coincided with a significant turnover in engineering personel. My concern was that this reshuffling and rebalancing of staff would be accompanied by a “loss of faith” in Tesla’s own engineering excellence. I interpreted the news of the involvement of the four transmission companies in this light.
It is a tremendous relief to learn that a solution to the transmission problem has been found and from within Tesla itself! Excellent, verging on Hilarious. In spite of (or perhaps because of) the pressure, Tesla engineers have created a solution which seems to out-flank the work of mature, prestigious companies like Ricardo.
If they can achieve this then I sincerely hope that they will be rewarded with a bit of stability and who knows - even the resources to create a BEV Whitestar?
Keith, that makes more sense to me than anything else I’ve heard so far on this subject and I think it kills the multiple gears solution until somebody comes up with a better way of achieving a quick change. I won’t be holding my breath
Keith: We don’t know what the problem with the transmission was, but I have not seen any statements from reliable sources to support the idea that shifting is the problem. You talk a lot about the motor’s inertia and the problem with slowing it down. It is already designed to be switched into regen mode which is powerful enough for Tesla to be concerned about too much breaking causing skidding in some situations. It is also possible to apply reverse torque electrically and reduce the speed even more dramatically. Consider that the motor is powerful enough to accelerate the car to 60 mph in 4 seconds, consider that all of this power can be used to change the speed of the motor with no load, and you suggest that it would take 4 seconds just to slow the motor down! It could be almost instantaneous. The existing shift time is “way less than 1 second” according to an earlier blog quoting a Tesla engineer. I do agree with the general statements about beefing up the transmission, it is failing because it is not strong enough. The problem here is that Tesla wanted a small, light weight transmission and now they are trying to make it stronger with out making it bigger (which would in turn could require major re-design of the car). They have decided on their solution, and I agree completely as the primary rational for a multi-speed transmission is to keep an ICE near the peak of its power and torque curves, and this does not apply to electric motors.
Roy, it’s true we don’t know for sure what the problem was but it is clear that many companies could have supplied a transmission if the car were not powered by an electric motor, so it has to be something to do with the characteristics of electric motors. Changing from 1st to 2nd in a Tesla requires a drop in revs that must be close to the total rev range of many normal cars. That’s a heck of gap between gears. As you’ve pointed out adding more gears doesn’t make much sense when you have all the torque of an electric motor, so they have to make it strong enough to take the force of braking the motor down sharply to achieve a smooth change. As Keith points out, the motor acts as a flywheel and there’s quite a lot of force to be dissipated. This is going to cause wear in something and possibly breakages. My guess is that they can make it work but they can’t make it work in a durable and reliable fashion, good enough for the life of the car. Just too many conflicting requirements.
This is what Mac Powell of Tesla had to say on the subject in the Lotus newsletter:
DL: I understand the Tesla Roadster’s
transmission has been a major source of delays
to the programme schedule. What has been
behind the problems in that area and how are
the problems being overcome?
MP: You might think that a transmission is a known technology,
particularly when viewed against all the new technology being
incorporated into the car, but it’s not that simple.
As a new company it was difficult, initially, to get major manufacturers
to even talk to us, never mind commit any resource to actually help
design, engineer and build systems. We started off going down
a particular route with a transmissions supplier and we got to the
point where we realised that the way that particular programme was
headed, it wasn’t really going to meet our performance targets for
the car.
We chose, pretty late in the programme, to change course and go
with an alternative supplier with a different approach.
The transmission sounds simple: two-speed transmission and
therefore you depopulate a regular transmission, but if you think
about it, our gear shift between first and second is a factor of two
and the motor spins up to 13,000rpm, so first gear takes you to over
60mph and second takes you to over 125mph so that is a huge ratio
step against which we don’t have a conventional clutch.
There’s a rotor with a very high inertia and we have to change the
speed of that rotor very, very quickly to give us a performance shift.
There are also issues about electrical isolation because of the way
we use the charging system and the motor.
So, it isn’t straightforward. It isn’t ‘just another transmission’ and
some issues have been thrown up that weren’t anticipated and have
taken longer than we had hoped to resolve. With change of supplier,
change of design concept and with some of these unforeseen
Tesla aims to deliver supercar acceleration and technical issues to overcome, delays have been the result.
I was reading in many recent magazines about the transmission challenge you are facing in the pre-production vehicles. I know of a manufacturer of industrial power transmissions that may be able to help. Try www.magnadrive.com. I have not personally used their product. Rather, I was interested in it about 5 years ago for variable industrial ventilation. It’s a non-contact magnetic power transmission unit. They describe it better at their website better than I ever can. So, here’s a quote from their site -
MagnaDrive’s patented technology uses high power Neodymium-Iron-Boron permanent magnets to create an induced electromotive force used for torque transfer. The system physically separates the two elements of the motor system, placing magnet discs on the load shaft and a conductor assembly on the motor shaft. Motor torque is transferred to the load across an air gap. Varying the air gap between the magnets and conductor changes the strength of the magnetic field and hence controls output speed.
I really like the Tesla car and I applaud the determination of your company to develop such a unique, well thought out, and much needed product. I personally cannot handle the $90,000+ price tag of the initial production vehicle. But, when prices come down (or my $$$ goes up), I will be a Tesla owner. If anyone at Tesla would like to speak to me in greater detail, feel free to email me. - Paul
My understanding of the transmission problem is that there is too much torque, rotor speed, and internal inerta in the Tesla Roadster motor for traditional transmissions. At the higher gear ratio there is not enough torque to accelerate at a rate that will achieve the desired 0 to 60 MPH performance. At the lower gear ratio 13,000 RPMs do not allow for the desired top speed of the car.
The Tesla motor weighs only 70 lbs. Weight is a huge consideration in an electric car. What will be the weight of a sophisticated transmission? If a transmission weighs more than 70 lbs it may be a better solution to include two or more motors in the system. From a cost perspective, we have heard that the electric storage system is very expensive, but I have not heard the cost of the motor. I can imagine that a transmission might cost nearly as much as another motor, especially if the transmission is going to wear out prematurely.
It would seem to me that the way to solve this problem is to put separate motors on the front and rear drive system. This could be two motors, if the physics works out well, or maybe even four motors, each with less torque. With even more total torque but a higher gear ratio the car could both accelerate well, and have a high maximum speed, without the need for a transmission and the need to shift gears. With four motors they could all be controlled by computer, which could be great for performance and handling
Obviously, there may be an even greater peak power consumption with maximum acceleration, which might exceed the capacity of the electric storage system.
The additional benifits of this system would include power to all four tires, which will allow for greater acceleration without tire slipage.
I would love to drive my four wheel drive Tesla roadster to my favorite ski area. At this time it would appear that the roadster is pretty much locked into a rear wheel drive, one motor system. Maybe Tesla will have an innovative ski rack idea for the Whitestar.
I updated my zip file at www.elgersmad.homestead.com/files/resonance/proof.zip
Read the readme.txt file or it will be cryptic. I added a series of examples for how to connect the plasma tube/ionization tube and an oscillator circuit. I’m sure you’ll find some use for these energy conserving circuits. If should manage to construct a car that doesn’t need more than 1 12 Volt lead acid battery to run 90 to 99% of the time, could I have a free one? It is Over Unity to the point that after warm up, I should be able to drive it and charge the battery.
Love your car. I’m wonder how long it will be before a australian will be able to come over to the states and buy a Telsa sports car.
As they seem a top idea, and would love to have one.
So are you gonna tell us which DSP?
James Elger: Your proposed “overunity device” appears to be a circuit that converts a continuous flow of low power electricity into brief high power pulses. Easy to do with capacitors or other types of energy storage devices, but it takes time to charge those capacitors, and no power is produced during that time. To determine total energy input/output, you need to integrate the power over time, and you will find that the total watthours out are slightly less than the total watthours in, due to efficiency losses in the circuit and waste heat produced. Sorry, no “overunity”, no violations of the laws of energy conservation.
Power and Energy are related, but they are not the same thing! Confusing power (watts) with energy (watthours) is like confusing distance (kilometers) with speed (kilometers per hour).
Sorry, but there have been too many proposals posted, claiming ways to “increase driving range” that don’t really work. The engineers at Tesla Motors don’t really pay attention to them.
My first foray into the tesla blog.
Question for all the engineers out there: what is the feasibility and how much extra range would be delivered by solar cells integrated into the car roof for free charging while parked or driving during the day, and small wind turbines under the front end to capture 60mph air resistance on the highway? And any idea of the extra cost? Thanks.
Perhaps a good idea for tesla. Some other EV runs it’s airconditioning from a small onboard solar panel and runs even when you are parked with the engine off - makes sense since you need the air conditioning most during the day and who wants to step into a hotbox after being parked for awhile in the sun.
I have been looking into designing a small inverter for running a small industrial ac induction motor. I am curious how you came to a decision between FOC control and DTC (direct torque control)? From what I understand DTC seems to be better for transient response issues, but FOC seems to be a more mature technology. Any thoughts?
Solar paint (developed / found out by developing rust protection paint), currently in testing stage on steel frames in the US, could solve some of the problems cooling the car when parked, extend range e.g.
www.ecogeek.org/content/view/1441/83/
Anyone at Tesla looking in that option/matter/possibility by talking to Swansea University?
What about supercapacitors?
- especially with the one from the ultra secret company EEStor Inc. ?
Capacitor systems for temporary energy storage when the grit cannot take the power back (from recuperative breaking)
are used since centuries in good old European Tramway systems.
If Lockheed Martin signs a agreement
to integrate and market Electrical Energy Storage Units (EESU), ceramic batteries and super capacitors
from EEStor, Inc., for military and homeland security applications it might be worth a
good, hard and long look.
www.webwire.com/ViewPressRel.asp?aId=56432