SaberRD Design Example: Electric Vehicle Powertrain Simulation with Single and Two Gear Transmission

This document presents the details of the simulation of a single gear and a two-gear transmission system for an Electric Vehicle (EV). It is quite common that the transmission system has a single-gear ratio between the drive train and the wheel axle in an EV. Recent studies say that the two-gear system can enhance the range by around 5%. The goal of simulation in this design example is to draw the advantages of two-gear transmission over the single-gear transmission.

Central to this powertrain design, a high fidelity PMSM motor model produced with the JMAG FEA solver includes spatial harmonics, flux saturation, and frequency-dependent iron losses. The motor is fed current by a 3-phase Voltage Source Inverter (VSI) controlled by a FOC algorithm implementing Maximum Torque per Amp (MTPA) and Flux Weakening strategies and using the interceptive sinusoidal PWM method. The dc link voltage (365V) is realized by a Li-ion battery characterized using the Battery tool in SaberRD. The motor shaft is connected to the drive shaft through a transmission block. The transmission block helps to configure multiple gears. So, the model is used to evaluate the performance of the powertrain with a single gear and two gear transmission. The driveshaft is connected to a simplified car dynamics model accounting for the force of gravity on sloped terrain, as well as for the rolling and aerodynamic forces.

Circuit Snapshot:
Figure below is a snapshot of the top level schematic of the EV Powertrain design.

How To Run the Example:
Download the attached "" and unzip the contents. Open the powertrain1.ai_dsn in SaberRD and run the experiment, optimization_tests experiment listed in the Experiment Analyzer.

For more details of the design, how to run the design, etc., refer to the README.pdf file in the attachments.

This design example can be simulated only in SaberRD commercial edition 2020.03 and above.
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