Ground Fault Interrupter Waveform Simulation via Multi-Port Segmentation
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Solution Overview
Problem
Existing ground fault interrupters can only output a simple rectangular waveform for electric leakage tests, failing to simulate an alternating-current waveform and requiring external buffer circuits for adequate output capacity.
Innovation Solution
A ground fault interrupter design that includes a zero-phase current transformer, sensing resistor, signal detection circuit, electric leakage test circuit outputting multiple phase signals, alarm output circuit, and trigger circuit to produce simulated waveforms closer to actual alternating-current waveforms, enabling normal operation checks even for indeterminate waveforms like those through thyristor circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one port of a built-in IC or microcontroller is used to output an electric leakage test signal, then the device structure is simple, but the waveform is limited to simple rectangular waveforms and cannot simulate alternating-current waveforms
Solution Approach 1:
The patent divides the waveform generation function into multiple independent ports of the microcontroller. Instead of using one port to generate a complex waveform, multiple ports (at least two) are used to generate separate rectangular waveforms that are then combined to create alternating-current-like waveforms. This segmentation allows each port to maintain simplicity while the combination achieves waveform versatility.
Solution Approach 2:
The patent combines outputs from multiple microcontroller ports to create a composite waveform that simulates alternating-current characteristics. By merging the rectangular waveforms from multiple ports with different phases and duty ratios, the system achieves waveform complexity without requiring external circuitry, thus resolving the contradiction between structural simplicity and waveform adaptability.
2Device complexity
If one port is used to output the electric leakage test signal, then the circuit is simple, but the output capacity is limited and may require external buffer circuits
Solution Approach 1:
The patent combines the output capacity of multiple microcontroller ports to achieve sufficient drive capability for the test signal. By merging the current output capabilities of at least two ports, the system achieves the required output power without needing external buffer circuits, thus maintaining circuit simplicity while overcoming output capacity limitations.
3Device complexity
If a simple rectangular waveform is used for testing, then the test circuit is simple, but it cannot effectively simulate actual leakage current waveforms which are alternating-current waveforms
Solution Approach 1:
The patent segments the waveform generation into multiple rectangular waveforms with different characteristics (phase, duty ratio) generated by separate microcontroller ports. These segmented waveforms are then combined to create a composite signal that better approximates actual alternating-current leakage waveforms, improving test accuracy while keeping each individual generation circuit simple.
Solution Approach 2:
The patent dynamically adjusts the duty ratios and phases of the rectangular waveforms generated by multiple ports to simulate different alternating-current waveform characteristics. This dynamic control allows the test circuit to adapt to different testing scenarios and accurately represent various leakage current conditions without requiring complex analog waveform generation circuits.
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 the output of waveforms close to actual alternating-current waveforms, allowing for effective operation checks and normal functioning verification, including thyristor load waveforms, without the need for external buffer circuits.
Implementation Method 1
a zero-phase current transformer for detecting a leakage current flowing through alternating-current electric circuits
Implementation Method 2
a sensing resistor that converts a secondary-side output current of the zero-phase current transformer into a voltage
Data Source
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AI summary
Two or more electric leakage test signals having different phases are output to a sensing resistor (4), and a detected voltage generated in the sensing resistor (4) is taken in by a signal detection circuit (5) by using an A/D converter circuit (5a) having a differential input function. The signal detection circuit (5) outputs a tripping signal or an alarm output signal if the detected voltage is greater than or equal to a given voltage.