Electrical drivetrain without rare earth magnets and integrated inverter with inherent redundancy

The electric drivetrain is a key technology for future mobility. Safety, efficiency and cost reduction are main factors to influence the market acceptance of electrical vehicles. Within the MotorBrain project, the partners are developing a new drivetrain for an electric car with approx. 1000 kg weight. The drivetrain will avoid the use of rare earth magnets. The paper presents the electrical machine design from electromagnetic point of view in combination to the inverter design, with a combined view on motor and inverter. Different technology shifts are addressed: SMC rotor with ferrite magnets to reduce cost and avoid rare earth magnets; 9 phase system to reduce phase currents and utilize smaller power modules; new capacitor technology (ceramics) for better temperature performance and lower size; and enhanced safety technology with special safety measures in hardware (peripherals) and software (monitoring functions). The paper highlights the benefits of the different technologies in context of the electric, mechanical and electromagnetic system design.