Adaptive Charger Current Control for RESS SoC Stability
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Solution Overview
Problem
The frequent switching between charging and discharging modes in rechargeable energy storage systems (RESS) used in transport climate control systems leads to component wear, increased risk of errors, and reduced lifespan of the RESS management system.
Innovation Solution
The system is configured to remain in a charging mode when an external power source is available, avoiding toggling between charging and discharging modes, and modulating the charger current to maintain the RESS state of charge at a desired threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system frequently switches between charging and discharging modes to maintain RESS state of charge, then the state of charge can be maintained within thresholds, but component wear increases and system lifespan decreases
Solution Approach 1:
The system proactively charges the RESS when external power is available and the RESS SoC is below the upper threshold, rather than waiting for the SoC to drop and then switching modes. This preliminary charging action prevents the need for frequent mode switching later, thereby reducing component wear and extending RMS lifespan while maintaining reliable SoC management.
2Ease of operation
If the system toggles between charging and discharging modes to manage RESS current, then current control can be achieved, but the risk of operational errors increases
Solution Approach 1:
The patent extracts the decision-making logic for mode switching and replaces it with a continuous charging mode operation. By removing the discharging mode from the operational repertoire and using only charging mode with modulated current, the system simplifies control logic and eliminates the risk of errors associated with mode transitions, while still achieving effective RESS current control through the charging current modulation.
3Reliability
If the system charges and discharges RESS frequently to maintain capacity, then the RESS can be kept at desired SoC levels, but energy efficiency decreases
Solution Approach 1:
The system maintains continuous charging operation when external power is available, avoiding the stop-start nature of frequent charge-discharge cycles. By keeping the charging action continuous and modulating the current level rather than switching modes, the system maintains RESS capacity while minimizing energy losses associated with repeated cycling, thereby improving overall energy efficiency.
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 reduces component wear, enhances the lifespan of the RESS management system, improves energy efficiency, and minimizes the risk of the transport unit leaving a facility with an undercharged RESS.
Implementation Method 1
modulating a rechargeable energy storage source (RESS) current provided by the RMS and configured to charge a RESS of the power system
Data Source
AI summary
Methods and systems for operating a rechargeable energy storage source management system (RMS) to power a load while a power system is connected to an external power source are provided. One method includes determining a charger is connected to the external power source and enabled. The method also includes modulating a charger current from the charger to a rechargeable energy storage source management system (RMS). Also, the method includes modulating a rechargeable energy storage source (RESS) current provided by the RMS and configured to charge a RESS of the power system. Further, the method includes monitoring a RESS state of charge (SoC), monitoring the RESS current provided by the charger, and comparing the RESS SoC with a desired RESS SoC threshold. Upon the RESS SoC reaching the desired RESS SoC threshold, modulating the charger current for powering the load while avoiding decreasing the RESS SoC.