|
1 |
Motor loss CFD modeling & analysis
With the increment of high-speed electric vehicles, motor loss analysis is becoming more crucial, as this is a critical factor in motor cooling. Without a proper cooling system, the accumulated heat caused by loss reduces the motor’s efficiency, and may eventually cause the malfunction of motor. To analyze motor losses, a 2D electromagnetic CFD simulation model using Ansys and STAR-CCM+ has been developed. By coupling these programs, it is possible to overcome the limitations of each individual model using only one program, and to achieve more precise result. Through the use of equational add-on modeling, most types of loss, including windage loss, copper loss, stator iron loss, and rotor iron loss, can be modeled and separated for analysis, including contour maps of working conditions for total and separated loss or motor total efficiency. Additionally, while the loss model is important in itself, a 3D thermal CFD simulation model is planned that will use the separated loss analysis result, incorporating several types of motor cooling systems.
 - Electromagnetic IPMSM model
 - IPMSM Loss & efficiency map given by model
PE energy flow modeling
To predict the loss and temperature of the motor, 1D model with four steps was constructed. First, a governing equation is developed for each part of the power electronics (PE) system: the motor, inverter, and reducer. This creates a heat loss model and derives a loss map for each vehicle. Second, we compare the loss map with the simulation map to ensure its validity. The model is then modified and advanced through comparison with the simulation map. Third, the model is tuned according to the type of car using a 4-axis dynamometer test. Finally, the model is produced to enable real-time loss prediction based on real-time driving modes. Through the process, a loss map based on the 4-axis dynamometer test is derived as the minimum point. In other words, the aim is to develop a PE energy flow methodology and obtain loss separation for each PE system component.
Additionally, we develop a model that predicts temperature based on the loss from the heat loss model. The motor is divided into three parts: the end coil, the mid coil, and the rotor. Heat transfer is modeled by considering the heat transfer relation for each part. In particular, the heat cooled by the oil must be considered according to the cooling method of the motor. Through this process, we develop a model that predicts the rotor temperature based on the end coil temperature.
 - PE 1D energy flow model build process
|
