Digital Phase Feed-Forward for AC Ripple Suppression
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Solution Overview
Problem
Conventional power supply systems face challenges in effectively suppressing low-frequency output voltage ripple due to the complexity and cost associated with high-frequency analog signal transmission and processing, which affects the accuracy and efficiency of power factor correction and AC line ripple suppression.
Innovation Solution
A power supply system employing a feed-forward mechanism that transmits phase information corresponding to AC ripple as a digital signal using a low-speed optical coupler from the first stage to the second stage, enabling phase and amplitude compensation for AC voltage ripple suppression, thereby simplifying the control loop and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-frequency analog signal transmission is used for AC ripple compensation, then AC line ripple suppression performance is improved, but system complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical/electrical analog signal transmission system with an optical digital signal transmission system. Specifically, it uses a low-speed optical coupler to transmit digital phase information from the first stage to the second stage, substituting complex high-frequency analog circuits with simpler optical communication components, thereby reducing system complexity while maintaining suppression accuracy
Solution Approach 2:
The patent changes the signal representation parameter from analog voltage/current signals to digital phase information. By detecting and transmitting only the phase angle of the AC ripple as digital data, the system achieves accurate ripple compensation without requiring high-frequency analog signal transmission, thus simplifying the control loop and reducing costs
2Measurement precision
If high-frequency analog signal processing is used, then AC ripple detection accuracy is improved, but system cost increases
Solution Approach 1:
The patent extracts only the essential phase information from the complex AC ripple signal, separating the critical parameter (phase angle) from the full analog waveform. This allows the system to achieve detection accuracy using simple digital phase measurement rather than complex high-frequency analog processing, significantly reducing system cost while maintaining precision
Solution Approach 2:
The patent employs a low-speed optical coupler, which is a cost-effective component compared to high-frequency analog signal processing circuits. This inexpensive optical component can accurately transmit phase information without requiring expensive high-speed analog electronics, making the system more economical while preserving detection accuracy
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
This approach enhances the suppression of low-frequency output voltage ripple, improves power factor correction, and reduces system complexity and cost by utilizing digital signal processing, ensuring accurate and efficient AC ripple compensation.
Implementation Method 1
a feed forward mechanism for transmitting phase information corresponding to AC ripple as a digital signal using a low-speed optical coupler from the first stage to a secondary side of the second stage
Data Source
AI summary
A power supply has a first stage for performing AC-DC voltage conversion and power factor correction and a second stage for isolated DC-DC voltage conversion. The power supply includes a feed forward mechanism for transmitting phase information corresponding to AC ripple. The phase information is transmitted from the first stage to a secondary side of the second stage as a digital signal using a low speed optical coupler, where the phase information is utilized by a DC-DC digital controller to implement AC ripple suppression using both phase compensation and amplitude compensation.