Solid-State Circuit Breaker Self-Test Using Current Sensing
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Solution Overview
Problem
Conventional solid-state circuit breakers lack a comprehensive self-test function for their switching devices, posing safety hazards and affecting the operation of subsequent circuits during power down, and existing self-test methods are incomplete or require power down.
Innovation Solution
A solid-state circuit breaker design with integrated switching devices, current sensors, and a control unit that allows for self-test before and during operation without power down, using current signals to determine the operational states of switching devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid-state circuit breakers are designed without regular self-test function, then device complexity is reduced, but reliability deteriorates due to safety hazards from undetected switching device failures
Solution Approach 1:
The circuit breaker performs self-diagnosis using its own operational components. The control unit monitors the on-state and off-state of switching devices through current sensing during normal operation and self-test modes, enabling the device to self-verify its functionality without external testing equipment or complex additional hardware
Solution Approach 2:
The same switching devices and current sensors used for normal circuit protection functions are also utilized for self-test operations. The auxiliary power branch and anti-reverse connection circuit enable dual-purpose operation, allowing the system to perform both load switching and self-diagnosis using shared components
2Measurement precision
If brief self-test switching-off is performed during operation, then some switching function is tested, but measurement precision deteriorates because only partial self-test can be achieved
Solution Approach 1:
The system performs comprehensive self-tests before actual operation to detect potential failures in advance. The control unit checks the on-state and off-state of switching devices prior to energizing the load, ensuring that any defects are identified before they can cause operational issues or require interrupting service
3Reliability
If self-test is performed during power down, then switching device states can be detected, but harmful factors are generated that affect the operation of subsequent circuits
Solution Approach 1:
An auxiliary power branch with anti-reverse connection circuit acts as an intermediary testing path. This separate circuit allows self-test operations to be performed independently from the main load circuit, isolating test signals and preventing them from interfering with or affecting subsequent circuit operations while still enabling comprehensive device state detection
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
Ensures safe and reliable operation of the solid-state circuit breaker with accurate self-test capabilities, detecting device states without affecting the operation of subsequent circuits and without requiring additional power sources.
Implementation Method 1
a first current sensor configured to sense a current flowing through the second switching device and generate a first current signal
Implementation Method 2
a second current sensor configured to sense a current flowing through the auxiliary power branch and generate a second current signal
Implementation Method 3
an anti-reverse connection circuit connected between the second node and the input end and between the second node and the output end, and configured to allow a current to flow unidirectionally from the second node to the input end and the output end
Data Source
AI summary
According to an embodiment of the present disclosure, there is provided a solid-state circuit breaker and its self-test method. The solid-state circuit breaker comprises an input end and an output end, the input end being adapted to be connected to a mechanical switch; a first switching device connected between the input end and a first node; a second switching device connected between the first node and the output end; a third switching device and a first resistive element connected in series between the input end and the output end; an auxiliary power branch connected between the first node and a second node; an anti-reverse connection circuit connected between the second node and the input end and between the second node and the output end, and configured to allow a current to flow unidirectionally from the second node to the input end and the output end; a first current sensor configured to sense a current flowing through the second switching device and generate a first current signal; a second current sensor configured to sense a current flowing through the auxiliary power branch and generate a second current signal; and a control unit configured to determine operation states of the first switching device and the second switching device based on the first current signal and the second current signal.