Welding power supply with detection of a disconnection for a hall current detector
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Solution Overview
Problem
Conventional methods fail to detect disconnections in the output line of a Hall current detector, which can occur due to line breakage or disconnection from a connector.
Innovation Solution
A disconnection detecting device comprising a Hall current detector, a power supply circuit, a bias resistor, and an output-line disconnection detection circuit that determines disconnections based on an output voltage exceeding a predetermined reference voltage when the welding power supply is off, with a switch to manage bias voltage during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional disconnection detection methods are used (detecting no current through Hall element), then power supply line disconnections can be detected, but output line disconnections cannot be detected
Solution Approach 1:
The disconnection detection function is segmented into two independent detection circuits: one for power supply lines and one for output lines. Each circuit uses a different detection principle adapted to its specific detection target, enabling comprehensive coverage of both power supply and output line disconnections simultaneously
Solution Approach 2:
A bias resistor is introduced as an intermediary component connected to the output line. This resistor creates a measurable voltage signal that serves as an indicator of output line integrity, enabling indirect detection of output line disconnections without interfering with the normal operation of the Hall current detector
2Reliability
If bias voltage is always applied to detect output line disconnections, then disconnection detection is enabled, but false positives occur during normal operation
Solution Approach 1:
The bias voltage is applied periodically only during the off-state of the welding power supply through a control switch, rather than continuously. This timing-based control allows disconnection detection when no welding current flows, preventing false positives during normal operation while maintaining detection capability
Solution Approach 2:
The bias voltage application is made dynamic and conditional based on the operational state of the welding power supply. The control switch automatically adjusts the bias voltage application according to whether the power supply is on or off, adapting the detection mechanism to operational conditions to eliminate false alarms
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
Enables reliable detection of output line disconnections in Hall current detectors, ensuring consistent performance and preventing false positives during normal operation.
Implementation Method 1
a Hall current detector that detects a welding current flowing through a welding power supply
Data Source
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AI summary
A disconnection detecting device includes a Hall current detector for detecting a welding current flowing through a welding power supply, a power supply circuit for providing a control power to the Hall current detector, a bias resistor connected between the output of the Hall current detector and the control power, and an output-line disconnection detection circuit for detecting a disconnection in an output line of the Hall current detector. The output-line disconnection detection circuit is configured to determine that the output line of the Hall current detector has a disconnection, based on an output voltage of the Hall current detector being equal to or higher than a predetermined reference voltage while the welding power supply is off.