Excavator Energy Storage Abnormality Detection
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Solution Overview
Problem
In excavators with electric work elements, a broken voltmeter can lead to inaccurate voltage detection of the electrical energy storage device, causing overcharging and potential degradation due to erroneous charging operations when the voltage is incorrectly determined as zero.
Innovation Solution
An excavator system with a voltage detection part, current detection part, and abnormality detection part that estimates the electrical energy storage state based on voltage and current measurements to determine abnormalities, preventing overcharging and degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If voltage detection is performed using a voltmeter, then voltage measurement is simple, but the voltmeter may break leading to inaccurate detection and overcharging
Solution Approach 1:
The patent introduces an intermediary estimation mechanism that uses current detection values and charge/discharge operation data to calculate and estimate the voltage of the electrical energy storage device. This estimation value serves as a mediator to verify whether the voltmeter's direct detection is accurate, preventing overcharging even when the voltmeter fails.
2Productivity
If initial charging is performed when voltage is detected as zero, then charging operation is initiated, but overcharging and degradation occur due to erroneous detection
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors both the voltmeter's detection value and the estimated voltage derived from current detection and charge/discharge operations. When the voltmeter shows zero but the estimated voltage indicates sufficient charge, the control unit provides feedback to prevent erroneous charging, thus avoiding overcharging and device degradation.
3Device complexity
If voltage detection relies solely on voltmeter, then detection system is simple, but abnormality determination is difficult when voltmeter fails
Solution Approach 1:
The patent makes the detection system multi-functional by enabling it to perform both direct voltage measurement (when voltmeter is working) and estimated voltage calculation (when voltmeter fails or for verification). The control unit universally handles both detection methods, allowing accurate abnormality determination regardless of voltmeter status.
Data Source
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AI summary
An electrical energy storage unit (120) of an excavator includes an electrical energy storage device (19) that accumulates electric power generated by a generator and an electric circuit that controls a charge/discharge operation of the electrical energy storage device. An abnormality detection part detects an abnormality of the electrical energy storage unit (120). An electrical energy storage state estimation part of the abnormality detection part obtains an estimation value of an electrical energy storage state of the electrical energy storage device (19) based on a voltage detection value obtained by a voltage detection part and a current detection value obtained by a current detection part. An abnormality determination part of the abnormality detection part makes an abnormality determination based on the estimation value obtained by the electrical energy storage state estimation part.