Switching Frequency Control for Power Supply Noise Reduction
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Solution Overview
Problem
Switched-mode power supplies experience noise and sound issues due to switching frequency fluctuation control, which increases terminal noise and transformer vibration.
Innovation Solution
A power supply apparatus with a transformer, switching elements, and a control unit that alternately repeats frequency variation within a predetermined range and a narrower range, or sets a constant frequency, to manage output voltage states and reduce noise and sound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If switching frequency fluctuation control is performed to reduce terminal noise, then terminal noise is reduced, but transformer sound increases due to varying switching frequency
Solution Approach 1:
The patent applies dynamics by making the switching frequency adjustable and variable rather than fixed. The control unit dynamically changes the switching frequency within a predetermined range based on operational conditions, allowing the system to optimize between terminal noise reduction and transformer sound minimization by adapting the frequency to different operating states
Solution Approach 2:
The patent changes the parameter of switching frequency within a predetermined range to resolve the contradiction. By varying the switching frequency dynamically, the system can reduce terminal noise when needed while avoiding frequency ranges that cause excessive transformer sound, thus balancing both harmful effects
2Object-affected harmful factors
If switching frequency is varied within a predetermined range to reduce terminal noise, then terminal noise is reduced, but the range of frequency variation causes transformer vibration
Solution Approach 1:
The control unit dynamically adjusts the switching frequency within a predetermined range rather than using a fixed frequency. This dynamic adjustment allows the system to vary frequency to reduce terminal noise while maintaining control over the variation to prevent excessive transformer vibration
Solution Approach 2:
The patent employs periodic variation of the switching frequency within the predetermined range. This periodic action allows the system to systematically adjust frequency to reduce terminal noise while maintaining stable transformer operation by controlling the nature and extent of frequency variation
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 terminal noise and transformer sound, balancing noise suppression and sound reduction while maintaining efficient operation.
Implementation Method 1
a feedback unit configured to output a feedback voltage to a primary side according to a voltage induced in the secondary winding of the transformer
Data Source
AI summary
The power supply apparatus alternately repeats a control between a first control of varying a frequency of switching operation within a predetermined range and for a predetermined cycle according to a frequency determined based on a feedback voltage, and a second control of varying the frequency within a range narrower than the predetermined range or a third control of controlling the frequency to be a constant frequency.