Power Storage Block Management Device SOP Deviation Control
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Solution Overview
Problem
Power storage systems with interconnected blocks face challenges in preventing excessively high currents during operation, particularly when reconnecting a disconnected power storage block, leading to potential overcharge or overdischarge and stress on system components.
Innovation Solution
A power storage system with a power converter, switches between power storage blocks and the converter, and a management device that calculates the state of power (SOP) for all blocks to set upper limits for charging and discharging, allowing controlled reconnection and preventing high currents by adjusting power levels based on current deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal resistance estimation is used to control power storage racks, then current uniformity is improved, but calculation and memory costs increase
Solution Approach 1:
The patent changes the control parameter from internal resistance (which requires complex calculations and memory) to state of power (SOP) deviation. By monitoring SOP deviation instead of estimating internal resistance, the system achieves current uniformity control with simpler calculations and reduced memory requirements while maintaining reliability.
2Reliability
If current control is applied immediately after reconnection, then current deviation is reduced, but excessively high current may still flow due to sudden changes
Solution Approach 1:
The patent applies preliminary action by detecting SOP deviation before it leads to excessive current flow. When a power storage rack reconnects, the system proactively monitors SOP deviation and applies current control adjustments in advance, preventing the harmful effect of excessively high current before it occurs rather than reacting after the problem arises.
3Device complexity
If power storage racks are operated without SOP-based control, then system simplicity is maintained, but current deviation and component stress increase
Solution Approach 1:
The patent implements feedback control by continuously monitoring the state of power (SOP) of each power storage rack and using this information to adjust current control. The management device calculates SOP based on easily measurable parameters (voltage, current, capacity) and uses SOP deviation as feedback to prevent excessive current flow, thereby reducing component stress while maintaining control system simplicity.
Data Source
AI summary
In a power storage system, a management device calculates a state of power (SOP) of a whole of a plurality of power storage blocks connected in parallel based on an SOP of each of the plurality of power storage blocks. At least one of the plurality of power storage blocks is disconnected from the power storage system, and when at least one switch is turned on to return at least one disconnected power storage block to the power storage system having the parallel-connected power storage blocks, the management device calculates an SOP of a whole of the power storage blocks after a return of the at least one power storage block based on a deviation in current between each of the power storage blocks including the at least one returned power storage block to determine an upper limit level of power or current flowing into a power converter.