Philip Georg Brockerhoff

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.

Analysis of sensor parameter characteristics and digital control on the electric drive's performance

Current and rotor position sensors are used in field-oriented control of electric drives. The sensors have internal measurement errors, limited bandwidth and signal processing delay times, which influence the control of the drive. The paper analyzes the influence of these parameters on the torque. The sensor influence is investigated for base speed (BS) and field weakening (FW) operation of the drive. An analytical analysis explains the sensor influence on the generated torque in detail and provides an empiric formula for the relationship of a measurement error and generated torque. The conclusions are confirmed by system simulation of the electric drive train in Simulink and measurement results from a test bench.

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.