Electric Vehicle Drive Control Using Battery Correlation Maps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric vehicle drive control systems are insufficient in calculating torque commands based solely on accelerator operations and motor output torque, as they do not adequately consider vehicle state factors like battery deterioration, temperature, and charge state, leading to inadequate output torque estimation and control.
Innovation Solution
A drive control device and method that utilize battery correlation maps stored based on different deterioration states, temperature, and charge states to select the appropriate map for controlling the electric motor output, estimating maximum output torque, and adjusting power distribution between the engine and motor accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque command is calculated only based on accelerator operation amount and motor output torque, then the control system remains simple, but the drive control accuracy and appropriateness deteriorate
Solution Approach 1:
The patent pre-calculates and stores multiple battery correlation maps corresponding to different battery deterioration states before actual operation. When the vehicle runs, the system only needs to select the appropriate pre-prepared map based on current battery state, avoiding real-time complex calculations while achieving accurate torque control that considers battery conditions.
Solution Approach 2:
The patent changes the control parameter from simple accelerator operation amount to a comprehensive set including battery deterioration state, charge state, and temperature. By introducing battery correlation maps that relate these parameters to internal resistance, the system achieves more accurate torque command calculation that adapts to actual battery conditions without requiring complex real-time modeling.
2Adaptability or versatility
If battery correlation maps for multiple deterioration states are stored and selected based on current battery state, then the drive control appropriateness improves, but the map storage requirement increases
Solution Approach 1:
The battery correlation maps serve multiple functions: they characterize battery internal resistance under different conditions, enable torque command calculation, and adapt the control system to battery deterioration states. By using the same set of maps for multiple control purposes, the patent achieves high adaptability without proportionally increasing storage requirements.
Solution Approach 2:
Instead of creating a completely new complex control model for each battery state, the patent uses localized correlation maps that capture the essential characteristics of battery behavior at different deterioration stages. Each map contains only the necessary charge state-temperature-inner resistance relationships for that specific deterioration level, minimizing storage while maintaining accuracy.
3Productivity
If maximum output torque estimation is performed for each battery situation, then the productivity and efficiency improve, but the calculation complexity increases
Solution Approach 1:
The patent pre-calculates the relationships between charge state, temperature, and internal resistance for different battery deterioration states and stores them as correlation maps. During vehicle operation, the system only needs to select the appropriate map and read the pre-stored data, avoiding complex real-time calculations while achieving accurate maximum output torque estimation that enhances productivity.
Data Source
AI summary
There are provided a drive control device, a drive control method, and a non-transitory computer readable storage medium storing a program that control driving of an electric vehicle includes: a map storage unit storing a plurality of battery correlation maps, the battery correlation maps corresponding to a plurality of battery deterioration states and defining a relationship of a charge state and a battery temperature with an internal resistance of a battery; a map selection unit configured to select one battery correlation map from among the plurality of battery correlation maps stored in the map storage unit based on a current deterioration state of the battery; and a motor output control unit configured to control an output of a vehicular electric motor driven by the battery based on the one battery correlation map selected by the map selection unit.