Losses in Efficiency Maps of Electric Vehicles: An Overview

Abstract

In some applications such as electric vehicles, electric motors should operate in a wide torque and speed ranges. An efficiency map is the contour plot of the maximum efficiency of an electric machine in torque-speed plane. It is used to provide an overview on the performance of an electric machine when operates in different operating points. The electric machine losses in different torque and speed operating points play a prominent role in the efficiency of the machines. In this paper, an overview about the change of various loss components in torque-speed envelope of the electric machines is rendered to show the role and significance of each loss component in a wide range of torque and speeds. The research gaps and future research subjects based on the conducted review are reported. The role and possibility of the utilization of the computational intelligence-based modeling of the losses in improvement of the loss estimation is discussed.

Efficiency and Core Loss Map Estimation with Machine Learning Based Multivariate Polynomial Regression Model

“…The total core losses P is obtained according to the non-constant parameters K h , K c , and K e are given in Equation (6). These parameters are tabulated in a lookup table and then applied in FE using the cubic spline interpolation algorithm [20].…”

“…In addition to electrical and magnetic losses, windage, friction, and stray losses are other issues to be considered in the efficiency calculation. These losses vary depending on the spindle speed, radius, and spindle length [6]. In this case, the yield expression is expressed by Equation (7).…”

“…However, rotor copper losses and accordingly low thermal load ability are the biggest disadvantages of these motors. Especially in electric vehicle applications, motors containing magnets are often preferred [3][4][5][6]. However, interior permanent magnet synchronous motors (IPMSMs), some of the most often used motors in electric vehicles, are very popular due to their high torque density, high efficiency, wide speed range, and reluctance torque in addition to magnet torque [7,8].…”

“…This graph (efficiency map), which is given as a function of the maximum torque produced by the motor depending on the motor speed and efficiency, is crucial in determining the area where the electric motor is most efficient in different driving combinations, especially when presented with the drive cycle. In addition, parameters such as motor total losses, dq axis flux and current values, and copper losses are also determined within voltage and current limits [6]. However, while doing this, the current, current angle, voltage, and torque values applied to the motor windings at each operating point, as well as the rotor speed and position, can be recorded in appropriate resolution.…”

Bond graph model of line-start permanent-magnet synchronous motors

“…In addition, the ohmic loss of the stator in LSPMS motors, which is the largest portion of the total motor loss, is decreased due to a significant reduction in magnetizing current and thus the input current amplitude of the motors. The less loss of the LSPMSM compared to the conventional IMs enables to have advantages of higher efficiency and power factor as compared to those of IMs [16][17][18]. In fact, the sample 2.2 kW LSPMSM achieves IE4 efficiency standard while its counterpart SCIM meets IE2 efficiency standard, in a similar volume [19][20][21].…”