Variable Resistor Control for Power Storage Module Rush Current

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Solution Overview

Problem

Existing power storage systems face challenges in reducing rush currents when connecting or disconnecting power storage modules during operation, which can damage the system and require time and labor, and may result in incorrect procedures leading to further issues.

Innovation Solution

A power storage system with a control method that uses a variable resistor to manage current flow by setting its resistance value based on the voltage difference between the system voltage and battery voltage, preventing excessive current from flowing and automating the connection process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If units are connected during operation of the system, then hot swapping is enabled, but a large rush current may flow through the system causing damage

Engineering Contradiction:
Improvehot swapping capabilityVSAvoidrush current
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

A variable resistor is introduced as an intermediary component between the power storage module and the system. This resistor temporarily limits the current flow during the connection process, preventing rush current damage while allowing the hot swapping operation to proceed. The variable resistor acts as a mediator that protects the system during the transition state of connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The resistance value of the variable resistor is dynamically adjusted based on the voltage difference between the system and the power storage module. When the voltage difference is large (indicating potential rush current risk), the resistance is increased to limit current. As the voltages equalize, the resistance is decreased or removed, allowing normal operation. This dynamic parameter change resolves the contradiction by adapting the current limitation to the actual system state.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If manual connection procedures are used, then connection can be performed, but time and labor are required and human errors may occur

Engineering Contradiction:
Improveconnection processVSAvoidconnection time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system automatically detects the voltage difference between the system and the power storage module, and the variable resistor automatically adjusts its resistance value based on this detection. The entire current limiting process occurs without human intervention - the system serves itself by automatically protecting against rush current during connection operations. This eliminates the need for manual procedure following and reduces connection time.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously monitors the voltage difference and provides feedback to control the variable resistor's resistance value. This closed-loop feedback mechanism ensures that the current is limited only when necessary (when voltage difference exists) and automatically removed when the connection is complete and voltages are equalized. This automated feedback control eliminates manual intervention while ensuring safe operation.

Inventive Principle:
Principle #23Feedback

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

The solution effectively reduces rush currents, shortens connection time, and prevents human error-related issues by automatically setting the resistance value of the variable resistor, ensuring safe and efficient operation of the power storage system.

Implementation Method 1

control to reduce a rush current can be performed... uses a variable resistor to manage current flow by setting its resistance value based on the voltage difference

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3016241B1Electricity storage system, electricity storage module, and control method
Publication Date: 2019.10.16 MURATA MFG CO LTD
  • EP3016241B1 patent drawingFigure 1
  • EP3016241B1 patent drawingFigure 2
  • EP3016241B1 patent drawingFigure 3

AI summary

[Solving Means] A power storage system includes, for example, a plurality of power storage modules connected in parallel to a power line and a system voltage acquisition unit that obtains a system voltage in the power line. The power storage module includes a power storage section formed of one or more storage batteries and a current control unit that controls a current that flows between the power storage section and the power line. The current control unit controls, according to the system voltage and a voltage of the power storage section, the current that flows between the power storage section and the power line.