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All-new Megane E-TECH Electric: delving into the heart of innovation - episode 3

Episode 3 - A patent for an eco-friendlier electric motor

For nearly 125 years, Renault has been constantly seeking to innovate. Its inventions have stood the test of time and are still used even today with many people not even realising it. Direct drive gearbox (1899), replacement of the hand crank with an electric starter (1909), addition of the ‘5th door’ (1961), central opening (1983), hands-free key card (2000). All these and more are Renault designs. The All-new Megane E-TECH Electric – the first of Renault’s Nouvelle Vague – sees Renault still innovating. More than 300 patents have been lodged for the design of the vehicle and its platform, of which we have selected seven to showcase over the summer period. In this third article, Edouard Nègre, electrical motor design leader at the Renault Powertrain Design department, sheds light on the engine featured on the Megane E-TECH Electric. He explains how the copper coils used for the rotor help reduce the car’s environmental impact by not requiring the use of rare earth.

25 July 2022

Renault leverages its expertise as pioneer in electrification as it develops new innovative features for electric vehicles every year. While most research and development has been focused on making batteries ever smaller and increasing their charge capacity, the engine has not been left to the wayside.

Renault sees the engine play a strategic role in the EV value chain and has even decided to design it entirely in-house. Focussed in the greater-Paris region, manufacturing and assembly of all the active parts (rotor, stator, power electronics, reducer) are done at the Cléon plant (Seine-Maritime, France) with fewer materials and energy used in the process, while R&D is concentrated at the Technocentre in Guyancourt (Yvelines, France).

“We invented a magnet-free rotor winding process. The magnet has been replaced by copper, which has a much smaller impact on the environment. The patented process also makes it possible to modulate the current flowing through the rotor so as to limit how much electricity the battery uses, especially at high speeds and on motorways.”

Edouard Nègre, electrical motor design leader at the Renault Powertrain Design department

What the innovation brings

The new rotor winding process for the Megane E-TECH Electric features a number of advantages:

  • it is more environmentally friendly as it is magnet-free, and therefore free of rare-earths
  • robust and reliable
  • optimised efficiency through limiting electricity use (by modulating current) and therefore reducing energy waste, especially at high speeds or on the motorway
  • production costs are lower as the technology is used for the engines on the ZOE, Twingo Electric, Kangoo Electric, and Master Electric, which are all made on the same production line in Cléon.

A brand-new process

Renault designed and patented a new magnet-free electrically excited synchronous motor for the All-new Megane E-TECH Electric. The technology makes the engine more efficient while reducing its impact on the environment. No more hard-to-recycle rare earth such as neodymium, whose extraction and processing produce toxic waste. Magnets have been replaced by copper coils for which the order and position of each wire have been studied to withstand the centrifugal force of the rotor.

In addition to the environmental benefits, the rotor winding technology means the Megane E-TECH Electric engine performs very well over wide a range of torque and speed. Unlike permanent magnet motors, Renault engineers have been able to use their invention to inject current into the rotor winding and thereby alter the level of magnetic excitation. As such, when the motor is not being heavily used, excitation can be reduced, this in turn uses less magnetic forces and means less energy loss.

To find out more

Patent reference for the magnet and rare-earth free rotor winding system:
Patent FR3106243 – Inventors: Emmanuel Motte, Damien Birolleau, Daniella Vivas-Marquez.

Emmanuel Motte 

Damien Birolleau

Daniella Vivas-Marquez

 

> Watch the 3rd video of our summer series <

Guillaume Jolit

Head of product Communication Renault

+33 6 08 50 45 52

 

Yann Chénot

Renault Press Officer, Electric vehicles & Ecosystems, Renault Classic

+33 6 25 63 22 34

 

Renault, a historic mobility brand and pioneer of electric vehicles in Europe, has always developed innovative vehicles. With the ‘Renaulution’ strategic plan, Renault has embarked on an ambitious, value-generating transformation moving towards a more competitive, balanced and electrified range. Its ambition is to embody modernity and innovation in technology, energy and mobility services in the automotive industry and beyond.

Renault, a historic mobility brand and pioneer of electric vehicles in Europe, has always developed innovative vehicles. With the ‘Renaulution’ strategic plan, Renault has embarked on an ambitious, value-generating transformation moving towards a more competitive, balanced and electrified range. Its ambition is to embody modernity and innovation in technology, energy and mobility services in the automotive industry and beyond.