Ripple Reduction Circuit Using In-Phase Control Voltage
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Solution Overview
Problem
Existing AC/DC power supplies face limitations due to significant current oscillations and complex designs, which affect their applications and compliance with power factor regulations.
Innovation Solution
A ripple reduction circuit is introduced, comprising a low pass filter, current mirror circuit, and linear voltage regulator to generate a control voltage in phase with the AC component of the output voltage, reducing ripples and improving power factor correction in AC/DC power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power factor correction is implemented using reactive circuit elements (inductors and capacitors), then the power factor is improved, but the converter complexity and current oscillations increase
Solution Approach 1:
The patent changes the operating parameters by using active switching elements instead of passive reactive elements, transforming the power factor correction mechanism from reactive to active control, thereby reducing complexity and oscillations while maintaining or improving power factor performance
Solution Approach 2:
The patent substitutes passive electrical components (inductors and capacitors) with active electronic control circuitry, replacing the traditional reactive power factor correction approach with an active switching-based solution that offers better control and reduced complexity
2Reliability
If traditional power factor correction circuits are used, then the power factor is improved, but significant current oscillations occur
Solution Approach 1:
The patent implements feedback control through switching elements that actively respond to and correct current oscillations in real-time, using the oscillation information to adjust switching timing and reduce the harmful current oscillations while maintaining power factor correction
Solution Approach 2:
The patent employs periodic switching action at optimized timing intervals that are synchronized with the oscillation frequency, creating constructive interference that reduces the amplitude of current oscillations while maintaining effective power factor correction
3Reliability
If isolated AC/DC switching power converters are used, then galvanic isolation is provided, but output voltage ripples are significant
Solution Approach 1:
The patent introduces an intermediary ripple reduction circuit between the isolated AC/DC converter and the load, which acts as a buffer to filter and reduce output voltage ripples while preserving the galvanic isolation provided by the converter
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
The solution effectively reduces or cancels output voltage ripples across a wide range, enhancing power factor correction and enabling efficient operation in various applications, including LED drivers, by regulating the load voltage based on the control voltage.
Implementation Method 1
a low pass filter adapted to filter an AC component of the output voltage to obtain a filtered DC voltage
Implementation Method 2
a linear voltage regulator adapted to regulate a voltage at the second output terminal based on the control voltage
Data Source
AI summary
A ripple reduction circuit for use with an AC/DC power supply providing an output voltage to a load is presented. The ripple reduction circuit includes an input terminal for receiving the output voltage and a low pass filter. The low pass filter is used to filter an AC component of the output voltage to obtain a filtered DC voltage. The ripple reduction circuit generates a reference current based on the filtered DC voltage and a control voltage having an AC component in phase with the AC component of the output voltage.