Power Factor Correction Circuit Using Real-Time Reference Signal Generation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power factor correction circuits face challenges in accurately generating a reference signal that aligns with changing input signals, leading to phase differences between voltage and current, which result in reduced power factor and increased Total Harmonic Distortion (THD), and require complex sensing circuits and precise timing.
Innovation Solution
A power factor correction circuit that includes a sensor to sense the voltage based on the current flowing into a power switch, a reference signal generator that detects and maintains symmetric gate-on times to sample and hold the sensing voltage, and a controller that outputs a gate-on signal to adjust the power switch accordingly, allowing the reference signal to be generated in real-time and align with the input signal's frequency and phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reference signal is generated by calculating the period of an input signal and generating a clock signal, then a reference signal can be produced, but it is difficult to generate a reference signal having accurate phase information
Solution Approach 1:
The patent uses a sensing circuit to directly copy the waveform characteristics of the input signal to generate the reference signal. Instead of calculating period and generating clock signals, the sensing circuit captures the actual voltage waveform, including its frequency and phase information, and uses this copied waveform as the reference signal for PWM modulation. This approach preserves accurate phase information while simplifying the circuit.
2Ease of manufacture
If input voltage is converted into current at a predetermined level and then converted back into voltage, then voltage-to-current conversion can be achieved, but it is complicated to generate a reference signal and requires a precise sensing circuit
Solution Approach 1:
The patent extracts only the necessary voltage waveform information from the input signal using a simple sensing circuit. Instead of performing complete voltage-to-current-to-voltage conversion, the sensing circuit directly senses the voltage waveform and extracts its essential characteristics (frequency, phase, amplitude) to generate the reference signal. This extraction approach simplifies the circuit while maintaining reference signal accuracy.
3Adaptability or versatility
If a reference signal is generated on the basis of only the information for one approximated period, then the reference signal can be generated, but when the frequency of the present period changes, an error is generated due to the discrepancy
Solution Approach 1:
The patent implements a dynamic reference signal generation system where the sensing circuit continuously monitors the input signal and updates the reference signal in real-time. Instead of using a fixed reference signal based on one approximated period, the system dynamically adjusts the reference signal to match the current input signal characteristics. This dynamic adaptation eliminates errors caused by frequency changes and reduces signal distortion.
4Adaptability or versatility
If a clock generator calculates one period of an input signal and generates a programmed sine wave, then a reference signal can be generated, but when an input signal is not a sine wave, distortion is necessarily generated
Solution Approach 1:
The patent changes the fundamental parameter of the reference signal from a fixed programmed sine wave to a dynamically adjusted waveform that matches the input signal. The sensing circuit captures the actual waveform parameters (frequency, phase, amplitude, and waveform shape) of the input signal and uses these parameters to generate a reference signal that adapts to any input waveform type, not just sine waves. This parameter adaptation eliminates distortion caused by waveform mismatches.
Data Source
AI summary
The present examples relate to a power factor correction device, a power factor correction method, and a corresponding converter, in which when an input signal inputted into the converter is changed, a reference signal is also changed to fit to the input signal in consideration of only the frequency and the phase of the input signal. Thus, even without a specifically designated control circuit, examples make it possible to improve power factor correction and Total Harmonic Distortion (THD) and to reduce the size of a semiconductor chip, and examples are potentially used for a device receiving waveforms other than a sine wave.