Development of a PMSM Traction Drive System for PHEV, HEV, EV using Virtual Prototyping

This paper outlines techniques to effectively simulate the powertrain of an electric vehicle at different levels of abstraction, with simulation goals ranging from overall efficiency and thermal analysis over hours of driving cycles, down to the nanosecond details of the inverter switching characteristics and losses. Such techniques can be leveraged to optimize motor and inverter controls, to verify power quality (THD and losses), and to simulate faults. Central to this powertrain design, a high fidelity PMSM motor model produced with an FEA solver includes spatial harmonics, flux saturation and frequency dependent iron losses. The use of virtual prototyping at different levels of abstraction offers several benefits. It permits design of a state of the art control methodology for PMSM motor drives, to verify performance over long drive cycles, as well as stability over the entire torque-speed range. Control algorithm aside, the traction motor's 3-phase drive inverter stage is an intricate component of the PMSM motor control system. Design engineers need access to a robust virtual prototype environment to implement detailed electronic configurations to verify PWM switching strategies and performance. Regenerative braking energy capture and control through the smart traction drive to charge the Lithium-ion battery pack can be also tested and fault conditions easily and safely applied. Moreover, in this study, both aging and adverse temperature effects can be applied to the battery pack and impacts to drivetrain range performance can be observed for any selected drive cycle. As hardware prototypes are usually not available at the early validation design phase, simulation is the only choice for confident confirmation of the traction drive concept. The simulation model of the traction motor system coupled with Lithium-ion battery pack is the executable specification recognized as the virtual prototype.