AEVA Forums

Weber, I reckon that mapping would be quite nice. It gives a similar effect to what the setup with an ACP system is, where the 'zero' point of the pedal moves along the range of travel as speed increases. This means no dead pedal travel when moving off from a stop, but regen controllable by the same...

I this running sensorless? If so, can you fit an encoder or similar?

The Loud Speaker Kit in Perth have some quite nice kits too, and you'll probably save a heap in freight compared to importing something that heavy from the US!   http://theloudspeakerkit.com/

That 'hybrid' motor looks to me like an IPM = Interior Permanent Magnet. Probably the best of both (induction vs PM) worlds at the moment, I think. Coulomb, regarding the Carbon motor in the Civic, yes, there is no overspeed region for that motor, you can't field weaken an ironless PM motor. Well no...

There's a checklist at the back of the NCOP14 document, so maybe the RTA and your engineer are both kind of right?

Sorry Richo, PM motors don't necessarily have a pf of 1. They still have inductance, which limits the current slew rate, which means at higher motor frequencies you don't have time to ramp the current up to 100% before it's time to ramp it down to -100% for the other half of the cycle. Therefore, at...

The real thing you want is a bi-directional charger, that can take power from the mains to charge the pack, and also put it back the other way. But they're a bit of a rare beast at this point in time, though I'd expect them to become more common in the future.

You'll want to be a bit careful about replacing indicators and brake lights with random LEDs - they won't be ADR compliant re brightness, emission angles, etc and the inspection people will fail you if they spot them. Having said that, a car this age probably had lousy lighting (lucas - prince of da...

You should also allow room inside the battery box for your fuse (they are NOT small!) and your HV contactors. This way when 12V power is cut to the contactors there is no exposed HV outside the battery box. Have something in place to fasten these items to. Think about where your busbars and BMS on t...

EV2Go, I think you have the energy use thing backwards. If the vehicle had regen, travelling 50% uphill then 50% downhill would be the SAME power as if the car drove that distance on the flat, ie the amount consumed by aero/rolling/efficiency losses.    If you don't have regen, the up/down scenario ...

I figure 250v - 600A forward and say 50V - 100A in reverse (it's only a trike) so I figured you would use lower rated contactors in reverse. Oh, OK. Yes, that's probably OK then. For a car, I think you'd want to design it for full torque in reverse too, otherwise you might get stuck in a parking sp...

Maybe I'm confused here, but when you guys talk about 30% in reverse, don't you really mean 30% speed ? I think you're going to still need 100% current because otherwise you won't be able to reverse up hills, gutters, etc. So this would mean any contactors and other bits in the motor connections are...

7circle, the WaveSculptor switches at 10kHz, with interleaved switching between phases, so the frequency 'seen' by the motor is 20kHz. It's above the audible hearing range (for humans, anyway...) so the issue you're talking about is non-existent with our controller. But yes, we probably could do tha...

The leadtime on the bus caps is 16-20 weeks. This is normal, and not an exceptional circumstance, so we can plan around it. We order well in advance, and our next delivery is due in 2-3 weeks. So our quoted 8 week leadtimes for controllers are valid. Jack wanted a controller *tomorrow*, and seemed u...

While Richo's numbers are a good start, they're only covering about half of the losses in the controller - the on resistance (or it's equivalent for an IGBT, the forward voltage drop Vf). The other major loss component in the controller is the switching losses. This is due to the fact that the MOSFE...

You still want the BMS in the trike while driving, ESPECIALLY if you're using Lithium Ion type cells that catch fire if you abuse them. The reason for this is that the undervoltage shutdown on your controller only shuts down if the total pack voltage goes too low. But this may be far too late for so...

Coulomb, the thing you're missing is that there's multiple types of PM motors. Ironless types (eg Ultramotive's CARBON) can't do field weakening, and hence can't do overspeed. Motor types with iron in the rotor can do both - but have increased motor losses (iron hysteresis losses) as the tradeoff.

The blue motor is mounted to a plate which then mounts to the dyno through a slewing bearing, and the plate is prevented from rotating by a loadcell. So we know torque. We also know motor speed exactly (both motors have position sensors) so power is simply torque x speed. As far as the mechanics of ...

The dyno works by running the two motors against each other. One is driving, and one is regenning. There is a motor controller for each motor, and they have their DC links connected together, along with a battery pack and a power supply to top up any losses. This way we can circulate large powers ar...

At EMC frequencies (AM radio and up...) the inductance of the DC bus capacitors means they don't really act much like capacitors. So just about all the high frequency noise you'd see on the motor cables will also be conducted out along the DC battery connection too. Layout makes a massive difference...

Oh, it's not too hard if you're designing the entire car! But for us, trying to explain to random joe in his garage about EMC? I'd be spending the next six months on the phone, talking about why the 1mm gap in his battery box meant that his AM radio had hum in it.

No, we don't recommend shielding. Basically it complicates everything and isn't actually likely to do that much - one gap in it somewhere (like in the battery box) and it won't work properly. Any VFD (including DC motor controllers) generates so much noise at the switching frequency, at at such high...

The Wavesculptor200 is booked in in the next two weeks for final C-Tick EMC testing. We're not expecting any problems, the prototype passed with no trouble, and our Wavesculptor20 for solarcars, which has MUCH faster edge rates (and therefore more emissions) passes with ease. The test only covers th...

The dV/dt issue is more of a problem on old modified square-wave drive inverters. Modern units operating at 10's of kHz PWM and with interleaved switching patterns have much less of it in the first place. The other thing that makes it a non-issue is that modern induction motors are designed to be dr...

Yes, it's quite a neat concept. You get an n-way redundant DC/DC converter, where 'n' is the number of cells in your main pack. You get a non-dissipative BMS. For hardly any extra effort you can make the DC/DC on each cell bidirectional, and can also charge weaker cells faster by pulling power from ...