DeepDrive to present dual-rotor radial flow generator for range extenders

A brief note on double rotor technology itself: Today’s electric motors in electric cars (regardless of their design – PSM, ASM or SSM) have an external stator and a rotor that rotates inside the motor, triggered by the stator’s magnetic field, i.e. it is an internal rotor. So-called external rotors, in which the stator is located inside and the rotor rotates around the stator on the outside, are not common in electric cars. Dual rotor technology combines an internal rotor and an external rotor in one motor. This is intended to increase energy density, making the drive more compact and lighter, or more powerful. In addition, material costs are reduced and efficiency is high, even in the partial load range.

DeepDrive previously implemented this principle in its wheel hub motor, which was introduced in 2021, and its central drive, which was presented in 2023. The Munich-based startup aims to solve the challenges involved in the production of double rotor machines and has attracted the interest of BMW and Continental, among others, both of which have invested in the company and are working on or already testing their own solutions using DeepDrive technology.

Car manufacturers are looking for range extender solutions

With the product that DeepDrive will present at the IAA Mobility in September, the Munich-based company is not introducing yet another solution for powering electric cars, but rather a double-rotor radial flow generator with high torque density that has been specially developed for modern range extender applications. Range extenders themselves have been around for years, for example, in the Chevrolet Bolt/Opel Ampera and the BMW i3. While this technology was only used for a very short time in Europe during the transition to purely battery-electric drives, extended range electric vehicles (EREVs) are experiencing a kind of renaissance in markets such as China, India and the USA. Instead of retrofitting combustion engine platforms at great expense, simple electric architectures are being supplemented with compact combustion engines to extend range, and demand is growing in markets with unstable charging infrastructure.

This has also led to numerous enquiries from car manufacturers at DeepDrive, as Alexander Rosen, co-founder and head of development at DeepDrive, explains. “More and more manufacturers are looking for scalable transitional solutions,” explains Rosen. “Initial discussions have resulted in a clear market impulse, and we are delighted to now be able to provide a response that is both technically and economically convincing.”

Since dual-rotor technology enables compact and efficient electric drives, generators with the same advantages are also possible. The DeepDrive MG 250 is said to be so compact that it can be coupled directly to the crankshaft of the combustion engine, without transmission losses, according to the company. The abbreviation ‘MG’ in the model name stands for ‘motor generator’, while 250 refers to the maximum torque of 255 Nm according to the data sheet. DeepDrive specifies a continuous torque of 180 Nm, with a peak power output of 150 kW over 30 seconds and a continuous power output of 120 kW.

The MG 250 has a diameter of 31 centimetres and a length of 16.5 centimetres, and it weighs 24 kilograms. Both the dimensions and the weight already include the SiC inverter integrated into the housing. The generator has an efficiency of up to 96.9 per cent and can cover a voltage range of 400 to 800 volts, which should facilitate integration into different vehicle platforms.

When used as a range extender generator, the MG 250 can also be used as a starter for the combustion engine. “Thanks to completely new winding technology, DeepDrive achieves unprecedented torque density with minimal material usage, resulting in a compact, lightweight and cost-efficient system that integrates seamlessly into new vehicle architectures,” the company specified.

The new range extender system will be unveiled to the public for the first time at IAA Mobility 2025, stand C23 in hall A1. In addition to the generator, DeepDrive will also be showcasing in-wheel and central drive solutions; In other words, its entire product portfolio.

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