EV Motor Mode Switching Under Battery SOC Limits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Battery electric vehicles face limitations in driving experience due to state of charge (SOC) constraints, which can limit supplied and regenerative power, disrupting the driving experience when switching between MT and EV modes.
Innovation Solution
A battery electric vehicle with a control device that adjusts the electric motor's output based on SOC, allowing switching between MT and EV modes while maintaining consistent acceleration and deceleration feelings by limiting modes when SOC is out of range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the driver selects MT mode to drive like a manual transmission vehicle, then the driving experience resembles MT vehicle operation, but the SOC may become close to overcharge or overdischarge regions causing power limitations that spoil driving enjoyment
Solution Approach 1:
The system dynamically switches between MT mode and EV mode based on real-time SOC conditions. When SOC is within the predetermined range, MT mode is available for authentic manual driving experience; when SOC exits this range, the system automatically transitions to EV mode to ensure reliable power supply and prevent battery damage, thus resolving the contradiction between driving experience and power reliability
Solution Approach 2:
The control device continuously monitors SOC and provides feedback to the mode selection system. This feedback mechanism detects when SOC approaches critical levels and automatically adjusts the operating mode accordingly, preventing power limitations while maintaining driving enjoyment through seamless mode transitions
2Reliability
If the driver selects EV mode for normal battery electric vehicle operation, then the supplied and regenerative power are controlled with reference to SOC, but the driving experience is constrained by SOC limitations on acceleration and deceleration power
Solution Approach 1:
The system dynamically adapts the control mode based on SOC conditions. When SOC is within the predetermined range, EV mode provides normal battery management with protected operation. When SOC exits this range, the system switches to MT mode to provide unrestricted driving experience, thus resolving the contradiction between battery protection and driving freedom
Solution Approach 2:
The system changes the operational parameters of the electric motor based on SOC conditions and selected mode. In EV mode, power is limited by allowable discharge/charge power based on SOC. In MT mode, the system adjusts power parameters to match MT vehicle characteristics, providing unrestricted acceleration and deceleration while still protecting the battery through mode-based control
3Reliability
If the control device limits the control mode to first mode when SOC is out of predetermined range, then the battery is protected from overcharge and overdischarge, but the driver's ability to select desired control mode is restricted
Solution Approach 1:
The system dynamically adjusts mode selection flexibility based on SOC conditions. When SOC is within the predetermined range, both MT and EV modes are available for driver selection, providing maximum versatility. When SOC exits this range, the system automatically limits operation to EV mode to ensure battery safety, thus resolving the contradiction between battery protection and mode selection flexibility
Solution Approach 2:
The control device uses SOC feedback to automatically adjust the available control modes. This feedback mechanism ensures that when SOC approaches critical levels, the system restricts mode options to protect the battery, while maintaining full mode selection flexibility when SOC is within safe ranges
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
Ensures a consistent driving experience by preventing gaps in acceleration and deceleration due to SOC limitations, enhancing driver satisfaction by allowing seamless mode transitions.
Implementation Method 1
uses as a traction power unit an electric motor configured to run on power supplied from a battery and stores regenerative power in the battery
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A battery electric vehicle includes an accelerator pedal, a shifter, a mode selector, and a control device. The mode selector selects either an EV mode or an MT mode as a control mode for an electric motor according to a mode selection operation by a driver. When the SOC of a battery is within a predetermined range, the control device controls the electric motor in the control mode selected by the mode selector. When the SOC is out of the predetermined range, the control device controls the electric motor in the EV mode regardless of the control mode selected by the mode selector.