Battery Contactor Voltage Checking for Stable Relay Closure
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Solution Overview
Problem
Insufficient supply voltage to relay coils in contactors can prevent complete closure, leading to faults in the contactor system.
Innovation Solution
A battery apparatus with a processing circuitry that sequentially checks and compares the supply voltage with a predetermined voltage before closing each contactor, allowing for stable closure by waiting for a predetermined time if the voltage is insufficient, and diagnosing faults after multiple comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the contactor is closed immediately without voltage checking, then the operation speed is improved, but the reliability deteriorates due to insufficient voltage causing incomplete closure
Solution Approach 1:
The patent applies preliminary action by checking the supply voltage before closing the contactor. The control unit measures the voltage at a first time point before closure, and only closes the contactor if the voltage meets the predetermined threshold. This preliminary voltage verification ensures that sufficient voltage is available before the closing action, preventing incomplete closure while maintaining operational speed.
2Reliability
If the supply voltage is monitored continuously before each contactor closure, then the reliability is improved, but the complexity of the control system increases
Solution Approach 1:
The patent performs voltage monitoring at a specific preliminary stage before contactor closure rather than continuously during operation. The control unit checks the voltage at a first time point before closure and makes a go/no-go decision. This targeted preliminary check achieves reliable operation without requiring complex continuous monitoring systems throughout the entire operation cycle.
Solution Approach 2:
The control unit integrates the voltage measurement and closure control functions within a single control device. The same control unit that manages contactor closure also performs the voltage measurement and decision-making, eliminating the need for separate dedicated voltage monitoring hardware and simplifying the overall system architecture while maintaining reliability.
3Productivity
If the contactor closes without pre-charging the external apparatus capacitor, then the productivity is improved, but harmful factors increase due to potential inrush current
Solution Approach 1:
The patent implements preliminary pre-charging action by closing the contactor only after verifying that the supply voltage has stabilized above the predetermined threshold. This voltage verification ensures that the power supply is ready and stable before connecting to the external apparatus, preventing inrush current issues while enabling rapid power transfer when conditions are met.
Data Source
AI summary
A plurality of driving circuits drive a plurality of contactors for connecting the battery pack and an external apparatus, respectively, based on a supply voltage. A processing circuitry control the plurality of driving circuits to sequentially close the plurality of contactors in a predetermined order, and check the supply voltage before closing each of the contactors.