Dual-Motor EV Charging Using D-Axis Heating for Torque Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electric vehicles with two drive motors, a significant temperature difference between the charging and non-charging motors during battery charging leads to unbalanced torque output, compromising traction stability.
Innovation Solution
A drive device with a controller that manages current flow between the two motors, specifically causing a d-axis current to flow in the non-charging motor during charging to equalize temperatures, thereby reducing the temperature difference and maintaining torque balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power is supplied from an external power supply to the battery via the neutral point of the first motor during charging, then the first motor can be used for charging, but a large temperature difference develops between the first motor (charging) and the second motor (not charging), causing unbalanced torque output and decreased traction stability
Solution Approach 1:
The controller executes a preliminary warming-up action on the second motor by causing a d-axis current to flow through it during the charging process. This preliminary heating prevents the temperature difference from becoming excessive before the charging is completed, thereby maintaining torque balance and traction stability.
Solution Approach 2:
The controller changes the electrical parameter (d-axis current) flowing through the second motor to control its temperature. By adjusting the d-axis current magnitude, the controller regulates the warming-up effect and equalizes the temperature between the two motors, resolving the temperature difference issue while maintaining charging functionality.
2Temperature
If a d-axis current is caused to flow in the second motor during charging, then the temperature of the second motor rises and temperature difference decreases, but additional energy consumption occurs in the second motor
Solution Approach 1:
The controller continuously monitors the temperature difference between the two motors and continuously adjusts the d-axis current in the second motor to maintain temperature equality. This continuous control ensures that the warming-up action is applied only when and where needed, minimizing unnecessary energy consumption while maintaining temperature balance throughout the charging process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively minimizes the temperature difference between the two motors, ensuring stable torque output and improved traction stability by synchronizing the charging and temperature-raising processes with the battery charging time.
Implementation Method 1
by causing the d-axis current to flow in the second motor, which is not used for charging, a temperature of the second motor not used for charging thereby rises
Data Source
AI summary
An art configured to suppress a temperature difference between two drive motors while charging a battery is provided. A drive device for an electric vehicle having a battery may comprise a first motor and a second motor electrically connected to the battery and configured to drive at least one driving wheel of the electric vehicle, and a controller configured to respectively control a current that flows in the first motor and a current that flows in the second motor. The controller may be configured to execute supplying power from an external power supply to the battery via a neutral point of the first motor. The controller may be configured to execute causing a d-axis current to flow in the second motor during the supplying the power.