Motor Operating Mode Control for EV Route Efficiency
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Solution Overview
Problem
Electric vehicles with multiple motors face inefficiencies in motor operation, particularly when operating at low rotation speeds and loads, leading to reduced fuel efficiency and increased electric costs, especially when traveling routes with varying terrain and traffic conditions.
Innovation Solution
An operating mode control device that estimates time-series torque and rotation speed requirements based on travel route information, calculates efficiency values for different motor operation modes, and determines the most efficient mode to control the vehicle, incorporating features like levitation control of axles to reduce resistance and optimize motor usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two motors are operated simultaneously to provide large driving force, then the vehicle can handle varying terrain and traffic conditions, but the motor system efficiency deteriorates due to low rotation speed and low load operation
Solution Approach 1:
The control device dynamically switches between single-motor and dual-motor operating modes based on real-time assessment of travel driving force requirements, vehicle speed, and motor efficiency characteristics. This dynamic adaptation allows the system to maintain high efficiency by using single-motor mode when sufficient, while providing adaptability through dual-motor mode when needed for varying terrain and traffic conditions.
Solution Approach 2:
The system changes operational parameters by switching between different operating modes (single-motor vs. dual-motor) based on calculated efficiency values. The control device determines the optimal operating mode by evaluating parameters such as travel driving force, vehicle speed, and motor efficiency characteristics, then adjusts the number of active motors accordingly to optimize the balance between adaptability and energy efficiency.
2Loss of energy
If single-motor mode is used to maintain high efficiency, then fuel efficiency and electric cost improve, but the vehicle may lack sufficient driving force for varying terrain and traffic conditions
Solution Approach 1:
The control device dynamically determines the appropriate operating mode by continuously monitoring travel driving force requirements and vehicle speed. This dynamic control ensures that single-motor mode is used when it provides sufficient driving force, maintaining high efficiency, while automatically transitioning to dual-motor mode when the terrain or traffic conditions require additional driving capability.
Solution Approach 2:
The system adjusts the number of active motors based on calculated efficiency values and assessed driving force requirements. By changing the operational parameter of motor quantity, the system achieves high fuel efficiency and low electric cost during normal operation, while retaining the capability to switch to dual-motor mode when terrain or traffic conditions demand increased driving force.
3Loss of energy
If motor operation is optimized for efficiency by selecting appropriate operating modes, then fuel efficiency and electric cost improve, but complex control calculations are required
Solution Approach 1:
The control device performs preliminary calculations of travel driving force requirements and motor efficiency characteristics before determining the optimal operating mode. By assessing these parameters in advance and calculating efficiency values for different operating modes beforehand, the system simplifies the real-time control decision-making process while achieving optimal fuel efficiency and electric cost performance.
4Reliability
If dual-motor operation is used to ensure sufficient driving force, then the vehicle can handle all terrain and traffic conditions, but cruising distance is reduced due to lower overall efficiency
Solution Approach 1:
The control device dynamically selects between single-motor and dual-motor modes based on real-time assessment of whether the required driving force exceeds what a single motor can provide efficiently. This dynamic switching ensures that dual-motor operation is used only when necessary for sufficient driving force, thereby maximizing cruising distance by maintaining high efficiency during normal operation while ensuring reliability when needed.
Solution Approach 2:
The system changes the operational parameter of motor quantity based on calculated efficiency values and assessed driving force requirements. By adjusting this parameter, the system achieves sufficient driving force for all terrain and traffic conditions while optimizing cruising distance through efficient single-motor operation during normal conditions and utilizing dual-motor mode only when absolutely necessary.
Data Source
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AI summary
An operating mode control device includes a travel driving force information acquisition unit configured to acquire a time-series travel driving force when traveling on a travel route; a vehicle speed information acquisition unit configured to acquire a time-series vehicle speed when traveling on the travel route; a motor operation estimation unit configured to estimate a time-series torque and rotation speed of the motor on the basis of a time-series travel driving force and vehicle speed; an efficiency calculation unit configured to acquire a time-series efficiency value of each operating mode on the basis of the time-series torque and rotation speed and calculate a total efficiency value; an operating mode determination unit configured to determine the operating mode having the highest total efficiency value as a default operating mode; and an operation control unit configured to control an operation by the default operating mode.