Vehicle RESS Current Compensation for Constrained Power Modules
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Solution Overview
Problem
Rechargeable energy storage systems (RESS) face challenges in maintaining balanced operation among power modules due to constraining events such as temperature differences or open circuit conditions, leading to imbalanced demand distribution and potential system stress.
Innovation Solution
Implementing a compensation strategy using a model predictive controller (MPC) to identify constrained modules and adjust current outputs, including setting constrained module outputs to zero or limiting them relative to unconstrained modules, while optimizing current distribution through power converters to balance state of charge (SOC) and manage thermal imbalances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power modules operate in balanced manner to spread demand equally, then system reliability and performance are improved, but this becomes problematic when constraining events cause imbalanced operation
Solution Approach 1:
The patent implements dynamic current output adjustment for power modules based on real-time temperature monitoring and constraining event detection. The controller continuously adapts current distribution among modules, transitioning from equal balanced operation to differentiated operation when constraints are detected, allowing the system to maintain reliability while adapting to changing conditions
Solution Approach 2:
The system changes operational parameters (current output levels) based on detected constraining events. When temperature differences or other constraints are identified, the controller modifies current output parameters for affected modules, reducing their current contribution while increasing it for unaffected modules to maintain overall system reliability
2Temperature
If temperature of power modules differs beyond desirable amount, then thermal management becomes challenging, but reducing current to constrained modules may impact power supply capability
Solution Approach 1:
The patent applies local quality by treating each power module individually based on its specific thermal condition. Modules with excessive temperature differences receive reduced current output, while modules operating within acceptable temperature ranges maintain or increase their current output, creating localized quality adjustments that manage thermal issues without compromising overall power supply capability
Solution Approach 2:
The system implements feedback control by continuously monitoring temperature of each power module and using this information to adjust current output in real-time. When temperature differences exceed thresholds, the controller receives feedback and automatically reduces current to affected modules, then monitors whether temperature uniformity improves, creating a closed-loop feedback mechanism that balances thermal management with power supply needs
3Object-affected harmful factors
If compensation strategy lowers current output for constrained modules, then thermal stress is reduced, but unconstrained modules must compensate to meet demand
Solution Approach 1:
The patent merges the operational capacity of unconstrained power modules to compensate for constrained modules. When certain modules have their current output reduced due to thermal constraints, the controller combines the available capacity of remaining modules to meet the overall current demand, effectively merging their outputs to maintain system productivity while protecting constrained modules from excessive thermal stress
Data Source
AI summary
Management of rechargeable energy storage system (RESS) included onboard to a vehicle to provide a high voltage (HV) output to a HV bus and a low voltage (LV) output to a LV bus. The management may include identifying a constrained module of the power modules, determining a current demand for a low voltage (LV) bus of the vehicle, and implementing a compensation strategy for managing the power modules to meet the current demand, including lowering a current output set for the constrained module relative to current outputs set for the unconstrained modules.