A Builders Guide For The Perfect Solid-State Tesla Coil

October 31, 2021 by Dave Rowntree 13 Comments

[Zach Armstrong] presents for your viewing pleasure a simple guide to building a solid-state Tesla coil. The design is based around a self-resonant setup using the UCC2742x gate driver IC, which is used in a transformer-coupled full-wave configuration for delivering maximum power from the line input. The self-resonant bit is implemented by using a small antenna nearby the coil to pick up the EM field, and by suitably clamping and squaring it up, it is fed back into the gate driver to close the feedback loop. Such a setup within reason allows the circuit to oscillate with a wide range of Tesla coil designs, and track any small changes, minimizing the need for fiddly manual tuning that is the usual path you follow building these things.

Since the primary is driven with IGBTs, bigger is better. If the coil is too small, the resonant frequency would surpass the recommended 400 kHz, which could damage the IGBTs since they can’t switch much faster with the relatively large currents needed. An important part of designing Tesla coil driver circuits is matching the primary coil to the driver. You could do worse than checkout JavaTC to help with the calculations, as this is an area of the design where mistakes often result in destructive failure. The secondary coil design is simpler, where a little experimentation is needed to get the appropriate degree of coil coupling. Too much coupling is unhelpful, as you’ll just get breakdown between the two sides. Too little coupling and efficiency is compromised. This is why you often see a Tesla coil with a sizeable gap between the primary and secondary coils. There is a science to this magic!

A 555 timer wired to produce adjustable pulses feeds into the driver enable to allow easily changing the discharge properties. This enables it to produce discharges that look a bit like a Van De Graaff discharge at one extreme, and produce some lovely plasma ‘fire’ at the other.

We’ve covered Tesla coils from many angles over the years, recently this plasma tweeter made sweet sounds, and somehow we missed an insanely dangerous Tesla build by [StyroPyro] just checkout that rotary spark gap – from a distance.

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A Coolant Leak The Likely Culprit For Aussie Tesla Battery Bank Fire

September 28, 2021 by Jenny List 36 Comments

Followers of alternative energy technology will remember how earlier in the year a battery container at Tesla’s Megapack Australian battery grid storage plant caught fire. Lithium ion batteries are not the easiest to extinguish once aflame, but fortunately the fire was contained to only two of the many battery containers on the site.

The regulator Energy Safe Victoria have completed their investigation into the incident, and concluded that it was caused by a coolant leak in a container which caused an electrical component failure that led to the fire. It seems that the container was in a service mode at the time so its protection systems weren’t active, and that also its alarm system was not being monitored. They have required that cooling systems should henceforth be pressure tested and inspected for leaks, and that alarm procedures should be changed for the site.

When a new technology such as large-scale battery storage is brought on-line, it is inevitable that their teething troubles will include catastrophic failures such as this one. The key comes in how those involved handle them, and for that we must give Tesla and the site’s operators credit for their co-operation with the regulators. The site’s modular design and the work of the firefighters in cooling the surrounding packs ensured that a far worse outcome was averted. Given these new procedures, it’s hoped that future installations will be safer still.

You can read our original coverage of the fire here, if you’re interested in more information.

[Main image source: CFA]

Commonwealth Fusion’s 20 Tesla Magnet: A Bright SPARC Towards Fusion’s Future

September 27, 2021 by Maya Posch 62 Comments

After decades of nuclear fusion power being always ten years away, suddenly we are looking at a handful of endeavours striving to be the first to Q > 1, the moment when a nuclear fusion reactor will produce more power than is required to drive the fusion process in the first place. At this point the Joint European Torus (JET) reactor holds the world record with a Q of 0.67.

At the same time, a large international group is busily constructing the massive ITER tokamak test reactor in France, although it won’t begin fusion experiments until the mid-2030s. The idea is that ITER will provide the data required to construct the first DEMO reactors that might see viable commercial fusion as early as the 2040s, optimistically.

And then there’s Commonwealth Fusion Systems (CFS), a fusion energy startup. Where CFS differs is that they don’t seek to go big, but instead try to make a tokamak system that’s affordable, compact and robust. With their recent demonstration of a 20 Tesla (T) high-temperature superconducting (HTS) rare-earth barium copper oxide (ReBCO) magnet field coil, they made a big leap towards their demonstration reactor: SPARC.

A Story of Tokamaks

CFS didn’t appear out of nowhere. Their roots lie in the nuclear fusion research performed since the 1960s at MIT, when a scientist called Bruno Coppi was working on the Alcator A (Alto Campo Toro being Italian for High Field Torus) tokamak, which saw first plasma in 1972. After a brief period with a B-revision of Alcator, the Alcator C was constructed with a big power supply upgrade. Continue reading “Commonwealth Fusion’s 20 Tesla Magnet: A Bright SPARC Towards Fusion’s Future” →

Hackaday Podcast 137: Maximum Power Point, Electric Car Hacking, Commodore Drive Confidential, And Tesla Handles

September 24, 2021 by Mike Szczys 3 Comments

Hackaday editors Mike Szczys and Elliot Williams marvel at a week packed full of great hardware hacks. Do you think the engineers who built the earliest home computers knew that their work would be dissected decades later for conference talks full of people hungry to learn the secret sauce? The only thing better than the actual engineering of the Commodore floppy drive is the care with which the ultimate hardware talk unpacks it all! We look upon a couple of EV hacks — one that replaces the inverter in a Leaf and the other details the design improvements to Telsa’s self-hiding door handles. Before we get to medieval surgery and USB-C power delivery, we stop for a look at a way to take snapshots of Game Boy gameplay and an electric plane engine that looks radial but is all gears.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (52 MB)

Continue reading “Hackaday Podcast 137: Maximum Power Point, Electric Car Hacking, Commodore Drive Confidential, And Tesla Handles” →

Tesla Door Handle Improvements

September 16, 2021 by Chris Lott 31 Comments

Automotive engineer and former Tesla employee [SuperfastMatt] takes at look at the notorious Tesla door handle design and how it’s changed over the years (see the video below the break). The original handle design consisted of many moving parts, switches and wires which were prone to failure. Strictly speaking, the door handle is located on the outside of the car’s interior. While it’s sheltered from direct exposure to the elements, it still experiences the extremes of temperature, humidity, and condensation. The handles were so prone to failure that a cottage industry sprang up to provide improved parts and replacements.

Tesla made various improvements over the years, culminating in the latest version which [Matt] reviews in this video. Nearly all the failure points have been eliminated, and the only moving parts, other than the handle itself, is a magnetic sensor to detect handle motion (previously this was sensed by microswitches). [Matt] indelicately opens up the control module, and discovers an NXP programmable angle sensor ( KMA215 ). This all-in-one sensor detects the angle of a magnetic field, and reports it over an automotive communications bus that’s become more and more common over the last ten years: Single Edge Nibble Transmission (SENT) aka SAE J2716. SENT is a low-cost, transmit-only protocol designed for sensors to send data to the ECU. Check out [Matt] decoding it on the oscilloscope and Raspberry Pi in the video — it looks pretty simple at first glance.

We agree with [Matt]’s conclusion that the door handle design has been significantly improved with this latest iteration, questions of whether one needs a retracting door handle aside. If you’d like to learn more about SENT, here is a tutorial written by IDT (now Renasas) applications engineer Tim White. This isn’t [Matt]’s first encounter with a Tesla door handle — back in 2012 we covered his project which used one to dispense beer. Thanks to [JohnU] for sending in this tip.

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Lithium Mine To Battery Line: Tesla Battery Day And The Future Of EVs

September 14, 2021 by Maya Posch 15 Comments

After last year’s Tesla Battery Day presentation and the flurry of information that came out of it, [The Limiting Factor] spent many months researching the countless topics behind Tesla’s announced plans, the resource markets for everything from lithium to copper and cobalt, and what all of this means for electrical vehicles (EVs) as well as batteries for both battery-electric vehicles (BEVs) and power storage.

A number of these changes are immediate, such as the use of battery packs as a structural element to save the weight of a supporting structure, while others such as the shift away from cobalt in battery cathodes being a more long-term prospective, along with the plans for Tesla to set up its own lithium clay mining operation in the US. Also impossible to pin down: when the famous ‘tabless’ 4680 cells that Tesla plans to use instead of the current 18650 cells will be mass-produced and when they will enable the promised 16% increase.

Even so, in the over 1 hour long video (also linked below after the break), the overall perspective seems fairly optimistic, with LFP (lithium iron phosphate) batteries also getting a shout out. One obvious indication of process to point out is that the cobalt-free battery is already used in Model 3 Teslas, most commonly in Chinese models.

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Tesla Automatic Driving Under Scrutiny By US Regulators

August 16, 2021 by Al Williams 66 Comments

The US National Highway Traffic Safety Administration (NHTSA) has opened a formal investigation about Tesla’s automatic driving features (PDF), claiming to have identified 11 accidents that are of concern. In particular, they are looking at the feature Tesla calls “Autopilot” or traffic-aware cruise control” while approaching stopped responder vehicles like fire trucks or ambulances. According to the statement from NHTSA, most of the cases were at night and also involved warning devices such as cones, flashing lights, or a sign with an arrow that, you would presume, would have made a human driver cautious.

There are no details about the severity of those accidents. In the events being studied, the NHTSA reports that vehicles using the traffic-aware cruise control “encountered first responder scenes and subsequently struck one or more vehicles involved with those scenes.”

Despite how they have marketed the features, Tesla will tell you that none of their vehicles are truly self-driving and that the driver must maintain control. That’s assuming a lot, even if you ignore the fact that some Tesla owners have gone to great lengths to bypass the need to have a driver in control. Tesla has promised full automation for driving and is testing that feature, but as of the time of writing the company still indicates active driver supervision is necessary when using existing “Full Self-Driving” features.

We’ve talked a lot about self-driving car safety in the past. We’ve also covered some of the more public accidents we’ve heard about. What do you think? Are self-driving cars as close to reality as they’d like you to believe? Let us know what you think in the comments.