Single Current Limiting Resistor for Electric Storage System Inrush Control
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Solution Overview
Problem
Existing electric storage systems require multiple current limiting resistors to prevent inrush currents when connecting the electric storage apparatus to both the motor generator and the charger, increasing costs and potentially causing system main relay deterioration.
Innovation Solution
The system employs a single current limiting resistor in conjunction with multiple relays to suppress inrush currents, reducing the number of parts and minimizing relay operation, which reduces power loss and extends relay lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple current limiting resistors are provided to prevent inrush current in both system main relay and charge relay, then inrush current is suppressed, but the number of parts increases and cost increases
Solution Approach 1:
The patent combines the inrush current suppression function for both system main relay and charge relay into a single current limiting resistor. The resistor is shared between the two relay circuits, eliminating the need for separate resistors in each circuit while still preventing inrush current damage to both relays.
Solution Approach 2:
The single current limiting resistor performs multiple functions: it limits inrush current for the system main relay and simultaneously limits inrush current for the charge relay. This multi-functional design reduces the total number of components required in the system.
2Ease of operation
If system main relay is operated to connect electric storage apparatus with charger, then power supply is enabled, but relay deterioration accelerates due to frequent operation
Solution Approach 1:
The patent divides the relay control function into two separate relays: system main relay for connecting the electric storage apparatus with the load, and charge relay for connecting with the charger. This segmentation allows independent control of each relay, enabling the system to use the charge relay for charging operations without requiring the system main relay to operate, thereby extending the system main relay's lifespan.
Solution Approach 2:
The patent introduces a charge relay as an intermediary component between the electric storage apparatus and the charger. This intermediate relay handles the charging connection separately, preventing the system main relay from being involved in charging operations and reducing its wear from frequent switching.
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 configuration effectively suppresses inrush currents while reducing the number of components and minimizing relay operation, thereby lowering costs and preventing premature relay deterioration.
Implementation Method 1
an electric current needs to be passed through a resistor (referred to as a current limiting resistor) in order to prevent a flow of inrush current
Data Source
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AI summary
[PROBLEM] To suppress an increase in the number of parts (the number of current limiting resistors). [SOLVING MEANS] In an electric storage system, a charger supplies power from an external power source to an electric storage apparatus and supplies power of the electric storage apparatus to an external device. A first system main relay and a second system main relay allow connection between a positive electrode terminal and a negative electrode terminal of the electric storage apparatus and a load, respectively. A third system main relay is connected in series with a current limiting resistor and, together with the current limiting resistor, is connected in parallel with the first system main relay. A first charge relay and a second charge relay allow connection between the positive electrode terminal and the negative electrode terminal of the electric storage apparatus and the charger, respectively. A third charge relay is connected in series with the abovementioned current limiting resistor and, together with the current limiting resistor, is connected in parallel with the first charge relay.