Energy Storage Control System Minimizing Power Dissipation
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Solution Overview
Problem
Energy storage systems with battery mismatch issues due to varying battery voltages and thermal gradients lead to suboptimal operation, current circulation, and potential damage, necessitating a method to optimize power processing and minimize losses.
Innovation Solution
A control system utilizing a central control processor to adjust power converter output voltages based on optimization algorithms, minimizing cumulative power processed and maximizing efficiency by determining a reference DC bus voltage that balances battery string voltages and reduces power dissipation, thereby addressing voltage mismatches and thermal gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If batteries are connected to a common DC bus without individual voltage regulation, then system complexity is reduced, but voltage mismatches occur leading to current circulation and battery damage
Solution Approach 1:
The patent divides the battery system into independently controllable modules, with each battery string equipped with its own power converter and control processor. This segmentation allows individual voltage regulation for each battery string while maintaining overall system functionality, preventing current circulation between mismatched batteries.
Solution Approach 2:
The patent introduces power converters as intermediary devices between the DC bus and individual battery strings. These converters act as mediators that regulate voltage and current flow, preventing direct harmful interactions between batteries with different voltage levels while maintaining system connectivity.
2Reliability
If power converters process full battery power, then voltage regulation is achieved, but cumulative power processing increases leading to higher losses and heat generation
Solution Approach 1:
The patent implements partial power processing by allowing batteries to directly connect to the DC bus when voltage levels are compatible, and only activating power converters when voltage regulation is actually needed. This reduces cumulative power processing through converters, minimizing energy losses and heat generation while maintaining voltage regulation capability.
3Adaptability or versatility
If battery voltages are allowed to vary freely, then system adaptability is improved, but thermal gradients increase causing suboptimal operation and potential damage
Solution Approach 1:
The patent implements feedback control through control processors that continuously monitor battery voltages and adjust power converter output accordingly. This feedback mechanism maintains voltage balance across battery strings, preventing excessive thermal gradients while allowing the system to adapt to varying operating conditions and battery states.
Data Source
AI summary
Controlling an energy storage system includes providing one or more constraints to an optimization problem algorithm, determining by the optimization problem algorithm a DC bus voltage value that results in an minimum total power dissipation for the plurality of power converters, calculating a respective control variable for each of the respective plurality of power converters based on the determined DC bus voltage value, and generating control processor executable instructions to implement control of each of the plurality of power converters to achieve the calculated respective control variable. A system for implementing the method and a non-transitory computer-readable medium are also disclosed.