No Need For Rare Earths: Vitesco Technologies Presents “Electric Drive For Maximum Sustainability”

* In Vienna, Vitesco Technologies shows an expansion to its latest axle drive platform 

* Life Cycle Engineering for an improved ecological balance sheet: A new rotor without permanent magnets forms the core of an externally excited synchronous machine 

* This technology is suited for main drives and for auxiliary drives, plus it can bring performance benefits 

* Additional technologies for higher efficiency and sustainability are shown at the Vitesco Technologies booth 

Vitesco Technologies, a leading international supplier of modern drive technologies and electrification solutions, is exhibiting innovations for more sustainable and more efficient electric driving at the 44th Vienna Motor Symposium. As a result of Life Cycle Engineering, the fourth generation of its fully integrated electric axle drive platform (EMR4, Electronics Motor Reducer) is being broadened by a new option to enable an even better life cycle assessment: A new rotor without permanent magnets is now part of the platform development. This rotor forms the core of an externally excited synchronous machine (EESM), which works without rare earths. This reduces the rotor costs, and it avoids the carbon footprint that comes with mining and processing the ores. 

“Top results in the sustainability and efficiency of electric cars will be achieved, if the vehicle drive is optimally adjusted to the specific scenario. The externally excited rotor without permanent magnets is a particularly sustainable option for our customers. The higher the performance requirements to the drive, the more economically attractive EESM technology becomes,” said Thomas Stierle, division head of Vitesco Technologies’ Electrification Solutions. 

Externally excited machines offer many advantages 

Up to now, most electrified cars have synchronous machines with permanent magnets in the rotor (so-called PSMs, permanent magnet synchronous motors). They are efficient and were generally regarded as easier to manufacture than externally excited machines, which use coils in the rotor to generate the magnetic field. Vitesco Technologies has overcome some substantial obstacles to designing externally excited machines: By harnessing many years of experience from series application and through targeted design changes, it became possible to achieve the same performance class with both technologies (PSM and EESM) – and to use the existing 

space in the platform design for both options. By applying a sophisticated winding principle, the innovative EESM rotor becomes an economically attractive option within the most recent drive platform. Especially, when high performance requirements necessitate a big magnet mass in a PSM, EESM machines will be more affordable and more sustainable. 

“Obviously, the EESM option requires an additional inverter module to control the coils”, said Dr. Gerd Rösel, head of innovation in the Vitesco Technologies division Electrification Solutions. 

“Nevertheless, we are really close to an EESM plug-and-play solution.” In addition to saving the cost for permanent magnets and the improved sustainability, this type of machine offers further advantages: “When the vehicle is sailing efficiently, the externally excited machine saves a watt hour of electricity per kilometer because there is no drag from a permanent magnet field in the rotor,” Rösel added, “this lowers the power requirement of the drive by up to five percent without the need for a mechanic decoupling device.” 

More highlights at the booth 

Among the topics covered in Vienna is the Battery Management System (BMS), which contributes to safety, to battery life and to efficient charging. An even higher level of safety is enabled by the Battery Pressure Sensor which detects gas emissions inside the battery module. The Vitesco Technologies Thermal Management Module ensures that all connected sub-systems of the drive are run in their optimal temperature span to facilitate maximum efficiency. 

Consistently transferring existing technologies to new applications is an important element of Vitesco Technologies’ contribution to sustainability. Proven combustion engine technology is regularly reused in battery- or hydrogen-based electric mobility: One example of this is the H2 Leakage Sensor that reliably detects even the smallest amounts of hydrogen in the system. The Air Control Valve, on the other hand, controls the air flow to the cathode side of the fuel cell. 

Furthermore, the company exhibits a demo version of its 48-Volt- System for smaller electric two-wheelers. It consists of an eDCU (Electric Drive Control Unit) and a compact powerful electric motor, fitted with a special inductive rotor position sensor. This system is being developed for series application within customer projects.