The project COSIVU aims at new system architectures for drive-train by developing a smart, com-pact and durable single-wheel drive unit with integrated electric motor, compact transmission, full SiC power electronics (switches and diodes), a novel control and health monitoring module with wireless communication, and an advanced ultra-compact cooling solution. The advances over the current state of the art can be summarized as follows:
• 20% higher energy efficiency and thus extended driving range due to dramatic reductions in the vehicle weight (30%) and in the losses in the power module (50%-70%)
• Increased performance, flexibility as well as safety and reliability due to close hardware-in-the-loop control based on integrated sensors, novel analysis algorithms coded into the microcontroller within the smart drive allowing in-situ functional and health monitoring and the bi-directional wireless communication between each drive and a central computer
• Reduced cost-of-ownership for the end-user due to prognostic maintenance advice, a factor 2 increase in lifetime and uptime of the smart drive unit, and minimized usage of expensive mechanical parts and cabling.
Within this project, these ambitious goals will primarily be demonstrated for commercial electric vehicles, which are even more demanding with respect to power performance, durability, and availability than other types of vehicles. In addition, the new architecture will be adapted to other vehicle platform such as vans, pick-up and even passenger cars. Specific and concrete examples will be given. Therefore, the feasibility of the novel drive-train architecture will be shown and demonstrated in a quite general way.
The main approach consists in substituting the central drive‐train, as known from conventional ICEVs, by compact and smart drives attached to the individual wheels, coordinated and controlled by a central vehicle computer via bi‐directional wireless communication. This will not only reduce weight, space and costs e.g. by removing large and heavy transmission units and differentials between the wheels, but also improve drivability, performance and driving safety e.g. due to torque vectoring possibilities. The main focus of the COSIVU project will be on the smart system, consisting of power and control/communication modules, to be mechatronically integrated into the next generation type of traction system (electric motor + transmission) on VOLVO commercial vehicles. ELAPHE will also demonstrate its use within this project on the passenger car.
This solution shall be applicable to all other types of vehicles as well. Hence, COSIVU intends to develop a general new standard of high-performance FEV drive‐train architectures with substantial advantages over existing technologies. The main objectives and highlights of the COSIVU project can be summarized as follows:
• Decentralized drivetrain system, managed by a central vehicle computer, for reduced weight and cooling complexity and thus improved energy efficiency
• One compact system package due to increased level of mechatronical integration for the electric motor, its simple transmission, and the compact inverter module
• Benchmarking of wireless communication between drive units and central computer vs. wired based solutions with respect to EMC issues, costs and durability
• Development of next generation of highly integrated inverter modules based on novel SiC technology (1200V, 500A) with innovative cooling concepts (e.g. double sided cooling), being capable of reducing energy losses by 50% and more
• Fail safe concepts like redundant wireless/wired communication links between the drivetrain unit and the central computer as well as between the drive‐train units at the same vehicle axle will enabling fast response torque coupling and thus increased functional safety
• Implementing of closed hardware‐in‐the‐loop technology at three stages to always guarantee optimal working conditions:
1) local, within the smart drivetrain unit
2) global short term and
3) global long-term by employing the central computer and the bi directional communication
• Implementation of innovative functional and health monitoring (SoF/SoH1) features, like thermal impedance spectroscopy for SoF/SoH determination of the inverter module or structure borne sound analysis for SoF/SoH determination of the motor/gear module
• Improvement of durability and total driving range by factor 2, due to application of latest virtual prototyping and reliability testing techniques
• High degree of vehicle integration and interoperability, demonstrated and proofed at a test rig, whereby even In vehicle tests are considered