Yves Burkhardt

Design and analysis of a highly integrated 9-phase drivetrain for EV applications

Cost and compactness are major success factors for electrical drivetrains for (hybrid) electric vehicles (EV). To increase the system power density, the focus is set on system integration, meaning to integrate e-machine, inverter, control, and gearing into one common housing. The inverter integration is facilitated by multiphase motors leading to lower phase powers and thus smaller inverter modules. To overcome price uncertainties of rare earth magnets, improved hard ferrite magnets are chosen as an alternative. In this paper, a new highly integrated drivetrain with a ferrite based 9-phase synchronous motor concept is presented with special focus on the main choices leading to the particular electromagnetic and mechanical design. The advantages of an integrated triplex inverter power supply and the new mechanical arrangement of a spoke-type rotor design will be presented, without focusing on the detailed electromagnetic behavior of the machine.

Highly integrated drivetrain solution: Integration of motor, inverter and gearing

Addressing power density and costs as major success factors for drivetrain solutions for e-mobility, a holistic system concept is necessary. Approaches which integrate e-machine, power electronics, control, gearing and cooling into a common housing offer high potential for compact and cost efficient (H)EV drivetrains. The transition to distributed multiphase inverter and motor concepts enables a novel level of system integration. A new smart stator tooth concept is presented. It comprises the integration of a segmented stator tooth together with dedicated power electronics and control electronics. This enables new degrees of freedom in terms of motor design, assembly and control.

A novel hybrid excited synchronous machine for (H)EV applications

Numerous different motor types have been examined recently to be used as main traction drives for EV applications. The aims are typically to increase power density and efficiency, fulfill safety requirements and to save costs. Due to price fluctuations of rare earth magnets in the past, such magnets are identified as unpredictable future costs and their content in a motor should be minimized. In contrast, traction motor concepts without rare earth magnets typically cannot achieve a comparable power and torque density. In this paper, a new hybrid excited synchronous motor concept is presented, combining aspects of permanent magnet (PM) machines and electrically excited synchronous motors. The benefits of each concept are combined while overcoming the individual drawbacks. After a presentation of the concept, the prototype design and manufacturing are explained. Test bench results proof the functionality of the concept. The highlights and benefits of this concept are summarized.

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.

Disc inverter in highly integrated 9-phase drivetrain for E-mobility

The paper describes the mechatronic integration of a nine phase electric motor and inverter for an electric car. Special focus is on the electronic development of a disc shaped 9-phase IGBT inverter integrated into the motor lid. The drive comprises automotive functional safe multicore ECU, rotational symmetric layout and sensor redundancy.