Efficiency and performance analysis of DTC‐based IM drivetrain using variable dc‐link voltage for electric vehicle applications

Abstract

In recent times, there has been a surge in R&D activities in the area of electric vehicles (EVs). This surge is fuelled by various governmental policies that aim at increasing the penetration of EVs on roads. This work aims at developing and analyzing drivetrain configurations for city commute vehicles. Since city commute involves frequent start stops, it is necessary to focus on the dynamic performance as well as the system efficiency. Here two drivetrain configurations are considered. The first has a battery pack, an inverter, and an induction motor while the second configuration has an additional dc-dc converter. A detailed control strategy for each drivetrain is presented. Moreover, an experimental setup is developed that mimics the behavior of a scaled-down vehicle. Both the configurations are subjected to extensive experimentation using the developed setup and it is found that despite the use of an additional dc-dc converter, the second configuration has better overall system efficiency in city driving conditions. To explain the results, detailed efficiency maps of the individual subsystem and the overall system are also presented. Furthermore, the drive cycle response and energy consumption analysis, for both the drivetrains for NYCC and city part-NEDC are presented.

Performance enhancement of electric vehicle traction system using FO‐PI controller

“…Urban and extra-urban driving cycles are used as a speed command to realise the real-time road operation. The driving cycle tests have been used in [7] as a benchmark for performance assessment of the EV system. Fig.…”

“…Therefore, non-linear controllers are expected to perform better and exhibit effective utilisation of the limited battery energy source. Some of the recent research work related to IM driven EVs is reported in [6][7][8]. Different approaches such as model predictive control [6], variable DC-link voltage control [7], and optimal design of stator and rotor slots of IM [8] have been proposed to enhance the performance of IM driven EVs.…”

“…Some of the recent research work related to IM driven EVs is reported in [6][7][8]. Different approaches such as model predictive control [6], variable DC-link voltage control [7], and optimal design of stator and rotor slots of IM [8] have been proposed to enhance the performance of IM driven EVs. Some other research attempts are reported in the literature [9][10][11][12] for speed regulation and efficiency enhancement of EV traction system.…”

Predictive torque control of induction motor with integrated DC‐link voltage optimisation

“…Regardless of the used control strategy, torque, and current ripple reduction of IM or permanent magnet synchronous motors drive can be achieved by implementing DC‐link voltage optimisation [27–34]. Since IM represents an inductive load, it follows that lower DC‐link voltage will lead to the lower current, and, consequently, torque ripple.…”

“…However, this approach is possible only for control strategies utilising modulator. The authors of [29, 30, 32, 33] determine the optimal voltage from the measured or reference IM quantities and IM model parameters. The disadvantages are the open‐loop algorithm operation and the lack of robustness against parameter variation.…”