FCEV SOC Control Using Altitude Prediction Without GPS
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Solution Overview
Problem
The driving performance of fuel cell electric vehicles (FCEVs) is adversely affected by state of charge (SOC) changes due to driving path characteristics, particularly on steep inclines and declines, leading to unstable SOC levels that can impact battery life and vehicle performance.
Innovation Solution
A method and device for controlling SOC using an accelerometer to determine travel distance and altitude changes, adjusting power generation based on these changes to maintain stable SOC levels, even without GPS signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS signals are used to determine altitude changes for SOC management, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses accelerometer data as an intermediary to indirectly determine altitude changes. Instead of directly measuring altitude with GPS, the system integrates acceleration data over time to calculate velocity and position changes, deriving altitude information from this integrated data. This intermediary approach allows the system to achieve altitude measurement functionality using existing onboard sensors without adding GPS hardware.
2Use of energy by moving object
If regenerative braking is used to charge the battery downhill, then energy efficiency is improved, but SOC stability deteriorates due to uncontrolled charging
Solution Approach 1:
The patent implements a feedback control mechanism where the calculated altitude change and predicted SOC are continuously monitored. When the predicted SOC exceeds the upper threshold after downhill regenerative braking, the system adjusts the target SOC downward and modifies fuel cell power generation accordingly. This closed-loop feedback ensures that energy recovery from regenerative braking is balanced with overall SOC stability, preventing overcharging while maximizing energy efficiency.
Solution Approach 2:
The system dynamically adjusts the target SOC based on real-time conditions including altitude changes, driving path characteristics, and current SOC levels. Rather than using a fixed target SOC, the controller adapts the target value dynamically - increasing it when uphill energy consumption is expected and decreasing it when downhill regenerative braking will occur. This dynamic adjustment allows the system to optimize energy efficiency while maintaining SOC within acceptable ranges.
3Power
If target SOC is increased before uphill driving, then energy availability is improved, but battery overcharging risk increases
Solution Approach 1:
The patent uses preliminary action by predicting future altitude changes based on stored driving path information before the vehicle actually encounters uphill sections. The system calculates expected altitude changes in advance and adjusts the target SOC proactively to ensure sufficient energy availability for upcoming climbs. This preliminary adjustment allows the fuel cell to generate appropriate power ahead of time, charging the battery in anticipation of future energy demands rather than reacting after SOC becomes critically low.
Solution Approach 2:
The system employs feedback control to prevent overcharging by continuously monitoring the relationship between target SOC adjustments and actual SOC levels. When the predicted SOC after uphill driving would exceed the upper threshold, the controller reduces the target SOC increase or adjusts fuel cell power generation accordingly. This feedback mechanism ensures that preliminary SOC increases are made conservatively and only to the extent necessary for upcoming energy demands, maintaining battery reliability while ensuring adequate energy availability.
4Stability of the object's composition
If fuel cell power generation is increased to compensate for uphill energy consumption, then SOC stability is improved, but hydrogen consumption increases
Solution Approach 1:
The system dynamically adjusts fuel cell power generation based on predicted altitude changes and driving conditions. Rather than maintaining constant high power generation to ensure SOC stability, the controller modulates fuel cell output according to real-time needs - increasing power generation before anticipated uphill sections and reducing it during downhill or level sections. This dynamic adjustment ensures SOC stability is maintained while minimizing unnecessary hydrogen consumption during periods when energy demand is low.
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
Provides stable SOC management by adjusting fuel cell power generation in response to altitude changes, ensuring consistent vehicle performance and battery life, particularly on challenging driving paths.
Implementation Method 1
determining, based on a measurement value of an accelerometer associated with the FCEV, a travel distance and a first amount of altitude change
Implementation Method 2
determining, based on a comparison between a current SOC and the target SOC, a required amount of additional fuel cell (FC) power generation
Data Source
AI summary
A state of charge (SOC) control method of controlling the SOC of a fuel cell electric vehicle (FCEV) in response to a change in altitude of the FCEV is provided. The method may include setting a first altitude at a start time of operating the FCEV; determining, based on a measurement value of an accelerometer, a travel distance and a first amount of altitude change during a predetermined time duration since the start time; determining an adjustment time for adjusting past driving data of the FCEV; determining, based on the adjustment time, a second amount of altitude change; determining, based on the second amount of altitude change, a target state of charge (SOC) as an input parameter; determining, based on a comparison between a current SOC and the target SOC, a required amount of additional fuel cell (FC) power generation; and controlling the FCEV.