Harmonic Correction Circuit for LED Power Factor
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Solution Overview
Problem
Aircraft electrical systems face negative impacts from unwanted harmonics, which can generate adverse electromagnetic field effects and disrupt other systems, necessitating effective harmonic compensation.
Innovation Solution
A harmonic and power factor correction circuit that detects input and output waveforms of LED lights, using a differential circuit and transistors to align their shapes and phases, ensuring low total harmonic distortion and maintaining a power factor of 1 by adjusting current and voltage waveforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LED lights are used for lighting, then energy efficiency is improved, but power harmonics and electromagnetic field interference are generated
Solution Approach 1:
The patent converts the harmful non-sinusoidal current waveform generated by LED drivers into a beneficial sinusoidal waveform by injecting compensating current through power factor correction circuitry. The circuit measures the LED current waveform and generates an equal but opposite harmonic content to cancel distortions, transforming the harmful electromagnetic interference into a beneficial power quality improvement.
Solution Approach 2:
The patent introduces an intermediary power factor correction circuit between the power source and LED driver. This intermediary circuit includes a current sensor, microcontroller, and power stage that measures the LED current and injects compensating current to harmonics, acting as a mediator that transforms the harmful current waveform into a beneficial sinusoidal waveform without altering the LED operation.
2Object-generated harmful factors
If harmonic compensation is implemented, then electromagnetic field interference is reduced, but circuit complexity increases
Solution Approach 1:
The patent implements a universal power factor correction circuit that simultaneously performs multiple functions: it corrects power factor, compensates for harmonics, and provides electromagnetic field interference reduction. By consolidating these functions into a single circuit architecture with shared components (current sensor, microcontroller, power stage), the patent reduces overall system complexity compared to implementing separate circuits for each function.
Data Source
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AI summary
A harmonics correction circuit is implemented as an independent device (such as a SiP or ASIC), and includes (1) a first node, (2) a second node, (3) a first current path extending from the first node to the second node, (4) a second current extending from the first node to ground, (5) a third current path extending from the first node to the second node, (6) a sense resistor electrically connected to the second node and to ground, (7) a differential circuit (e.g., a differential amplifier or other type of operational amplifier ("op-amp")) that has a first input, a second input, and an output, (8) a transistor comprising a gate that is electrically connected to the output of the differential circuit, a drain that is electrically connected to the third current path, and a source that is electrically connected along the third current path.