Reference Flux Linkage Selection and its Impact on Direct Torque Control Based
Induction Motor Drive Performance
In recent years, the rise in developing nations’ economic activities has resulted in the rapid
expansion of cities. This expansion of cities has emanated an increase in vehicular traffic, which
has led to deterioration in air quality. The deterioration in air quality is mainly because of the
emission from the internal combustion engine vehicles, which shared nearly 20-25% of the total
air pollution. To address the problem of unprecedented air pollution caused by the internal
combustion engine-based vehicle, governments worldwide have launched various programs,
policies, and incentives to increase penetration of vehicles that are not fossil fuel-based. One of
the acceptable solutions is to shift electricity-based transportation, i.e., adaptation of electric
vehicles (EVs). The major challenge in the faster adoption of EVs is to develop affordable electric
vehicles that fulfill the need of the market and mass users. One possible way to accomplish these
targets is to develop an efficient and low-cost drivetrain, apart from high-capacity batteries, in a
short span of time. To develop EV drivetrain in reduce time, it is essential to adapt the available
speed control methods proposed for industrial applications to modify for use in electric vehicles.
In this report, such an adaptation is proposed for an EV drive with direct torque control (DTC) of
induction motor (IM).
In the DTC strategy, the reference flux linkage has significantly impacted its performance.
However, it is seen that there is no generalized accepted method for determining the reference flux
linkage value. It depends on individual applications. Thus, in this report, implementation of speed
control DTC based IM drive over a wide speed range is proposed. For the successful
implementation of DTC based IM drive over a wide range of speed and torque, the selection of
suitable reference flux linkage method is proposed. The proposed method calculates reference flux
linkage, considering the reference speed, required torque, and given DC voltage. The proposed
method is made acceptable for EV application with few modifications in the DTC algorithm.