Parallel Load Current Control for Inrush-Safe Disconnection Detection
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Solution Overview
Problem
Existing energization control apparatuses for parallel loads fail to accurately detect disconnections due to the influence of inrush currents, leading to incorrect determinations and premature shutdown of direction indicators in vehicles.
Innovation Solution
An energization control apparatus with a control portion, disconnection detecting portion, and prohibiting portion that prohibits disconnection detection for a predetermined period after energization starts, allowing the disconnection detecting portion to continuously monitor the supply current and reduce the impact of inrush currents, enabling quick detection of disconnections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If disconnection detection is performed continuously based on supply current, then disconnection can be detected quickly, but inrush current causes false detection errors
Solution Approach 1:
The prohibiting portion performs preliminary action by preventing disconnection detection during the inrush current period. It sets a prohibition flag when energization is detected and clears it after a predetermined time, thereby blocking false disconnection detections during the initial inrush current phase while allowing accurate detection afterward
2Reliability
If supply current is detected at a predetermined period since energization starts, then inrush current influence is reduced, but decrement of supply current after detection cannot be detected
Solution Approach 1:
The disconnection detecting portion continuously monitors supply current after the prohibition period ends, ensuring no detection time is lost. The prohibiting portion only blocks detection during the initial inrush current phase, then enables continuous detection thereafter, maintaining both accuracy and timely response to actual disconnections
3Speed
If disconnection detection is enabled immediately, then detection speed is high, but false detection occurs due to inrush current
Solution Approach 1:
The system performs preliminary action by detecting energization and setting a prohibition flag before disconnection detection begins. This preliminary step prevents false detections during inrush current while enabling fast detection immediately after the prohibition period expires, achieving both speed and reliability
Data Source
AI summary
An energization control apparatus includes a control portion, a disconnection detecting portion, and a prohibiting portion. The control portion controls energization to a plurality of loads coupled in parallel. The disconnection detecting portion repeatedly or continuously determines whether a supply current to the plurality of loads is less than a threshold value when the control portion energizes the plurality of loads, and the disconnection detecting portion detects a disconnection of a part of the plurality of loads when the supply current is less than the threshold value. The prohibiting portion prohibits a disconnection detection by the disconnection detecting portion for a predetermined period since the control portion starts to energize the plurality of loads, and the prohibiting portion enables the disconnection detection by the disconnection detecting portion after the predetermined period elapses.