The efficiency of an electric vehicle (EV) drivetrain is one of the factors that determine the driving range of the vehicle. During the driving condition, the efficiency can be increased by choosing an optimum value of reference flux linkage in the used control strategy. Presently, the optimum values of reference flux linkage are determined either by search or lookup table-based approach. However, these methods suffer from the convergence issues at optimum value, complex calculations, and large memory space. Hence, to eliminate the issues mentioned earlier in efficiency improvement techniques, an approach to determine the optimum values of the reference flux linkage based on current minimization for the desired operating conditions is proposed in this article. The drivetrain efficiency obtained experimentally using the proposed reference flux linkage selection method is compared with other methods. Using the proposed reference flux linkage method, the dynamic, field-weakening response and drive-cycle speed-tracking performance of the drivetrain configuration are examined using experiments. Furthermore, the input energy consumption of the drive cycles is also compared. The obtained experimental results confirm the feasibility and effectiveness of the proposed method to select the optimum value of the reference flux linkage in the drivetrain control strategy for the desired operating conditions.