Audi A2 e-tron Uses SiC Inverter to Reach 12.8 kWh/100 km
Audi has detailed the electric drive behind its most efficient A2 e-tron configuration. The rear-mounted APP350 motor uses silicon-carbide power electronics, thinner rotor laminations, revised stator wiring and a model-specific single-speed ratio to help the 140-kW A2 e-tron achieve a preliminary 12.8 kWh/100 km on the WLTP cycle when equipped with the optional efficiency package.
The November 3 technical release does not announce a new model or U.S. launch. Audi revealed the A2 e-tron in September for European customers, opened German orders on September 10 and plans first European deliveries in December 2026. The company has not announced U.S. sales.
Audi calls the A2 e-tron its most efficient production model, but the 12.8 kWh/100 km figure is a preliminary manufacturer result under Europe’s WLTP procedure. It applies to a specific 140-kW configuration with an optional package and should not be compared directly with an EPA range or MPGe rating.
What changed in the A2 e-tron drive
| Component | Audi’s change | Intended effect |
|---|---|---|
| Pulse inverter | Silicon-carbide MOSFETs replace conventional silicon bipolar transistors | Lower switching losses; Audi claims inverter efficiency above 97% |
| Inverter software | Switching frequency adjusts to motor speed and load | Reduces losses during common partial-load driving |
| Rotor | Laminations are more than 30% thinner than in the APP310 predecessor | Reduces magnetic iron losses |
| Rotor layout | Segments use a staggered rather than linear arrangement | Targets tonal vibration and low-speed motor noise |
| Stator | Winding changes from star to delta with fewer parallel branches | Moves operation toward efficient partial-load ranges |
| Transmission | Fine-machined teeth, low-viscosity oil and revised oil routing | Reduces friction and oil-churning losses |
Silicon carbide cuts losses in the inverter
The APP350 is a permanent-magnet synchronous motor positioned parallel to the rear axle on the Volkswagen Group’s 400-volt MEB architecture. Audi says it produces up to 350 Nm, or about 258 pound-feet, in the A2 e-tron applications described in the release.
Its pulse inverter converts battery direct current to the alternating current used by the motor. The new inverter uses silicon-carbide metal-oxide-semiconductor field-effect transistors rather than the silicon-based insulated-gate bipolar transistors common in earlier MEB hardware.
Audi says the SiC hardware can exceed 97% conversion efficiency. New control software varies the switching frequency by operating point: lower frequency means fewer switching events and therefore less energy lost as heat when the car is running at the medium speeds and loads common in city and rural driving.
The same electronics can add selected high-frequency harmonic components to the motor current to counteract unwanted sound. That is an active noise-control technique within the drive, not a claim that the cabin is silent. Audi has not published comparative decibel measurements in this release.
Motor construction targets both efficiency and noise
Audi says the APP350’s rotor laminations are more than 30% thinner than those in the APP310 predecessor. Thinner electrical steel reduces eddy-current and remagnetization losses, although the company does not quantify the motor’s stand-alone efficiency gain from this change.
The rotor magnets are also arranged in staggered segments. Audi says that layout avoids exciting the rotor’s first torsional vibration mode and reduces dominant tones when the vehicle pulls away. The stator winding changes from a star connection to a delta connection, while the number of parallel branches is reduced to improve efficiency in everyday partial-load operation.
Two ratios serve three rear-drive power levels
The APP350 uses a single-speed reduction gear, but Audi selected two final ratios for the A2 e-tron’s rear-drive versions. The 125-kW and 140-kW cars use a 10.21:1 ratio. The 170-kW version uses 11.53:1. Audi says each ratio keeps the motor in a more efficient part of its operating map for that output level.
Fine-machined gear teeth create smoother contact surfaces, allowing Audi to use a specially developed low-viscosity lubricant. Revised oil routing is intended to reduce the energy spent moving lubricant through the gearset. These are incremental changes, but EV efficiency depends on limiting small losses across the entire drive.
How the efficiency figure fits the broader A2 lineup
The 12.8 kWh/100 km result converts to roughly 7.8 kilometers per kWh, or 4.85 miles per kWh, on the WLTP cycle. That is a useful mathematical conversion, not a U.S. test result. Audi lists a preliminary 12.8–15.6 kWh/100 km range for the 140-kW model depending on equipment.
Audi offers the European A2 e-tron with three battery sizes and four total power levels. The longest-range version pairs 170 kW with an 84-kWh battery for up to 646 km, or about 401 miles, WLTP. That range belongs to a different configuration from the 140-kW efficiency headline, so the two specifications should not be combined into a single “most efficient, 646-km” claim without qualification.
German prices begin at €38,200 for the 125-kW model with a 52-kWh battery. The 61-kWh version starts at €41,900, the 170-kW/84-kWh car at €48,900, and the 240-kW top model at €51,200. Audi’s new drive release focuses on the three APP350 rear-motor outputs; it does not explain the complete top-model powertrain.
Why this matters beyond one compact EV
The APP350 is Volkswagen Group hardware developed for MEB vehicles, so changes to the inverter, motor and transmission can inform other products that share the architecture. Chiefs Review has covered the Volkswagen ID. Tiguan and its MEB-based range strategy, although Audi has not announced that every A2 e-tron improvement will appear in that model.
The A2 launch is also part of Audi’s wider attempt to refresh its lineup while cutting costs. Chiefs Review recently reported on Audi’s reduced 2026 financial outlook and falling deliveries. The A2 e-tron is positioned as a lower-priced European entry point, but the company has not disclosed order volume or profit margin for the model.
For buyers, the confirmed takeaway is narrower: Audi has documented how the rear-drive A2 e-tron reduces electrical, magnetic, acoustic and mechanical losses. Real-world consumption will still vary with temperature, speed, tires, options, traffic and charging losses, and no independent road test is implied here.
Featured image: Audi A2 e-tron APP350 drive-unit illustration showing the exploded motor assembly and its rear-axle mounting position; this is an engineering illustration, not a vehicle photograph. Image A263798, © AUDI AG. Audi states that it may be used free of charge for editorial purposes. Image source and rights notice. No changes were made other than WordPress image scaling.