Boost Converter Acoustic Noise Reduction via Phase-Shifted PWM
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional boost converters generate acoustic noise in the audible frequency range, which can be bothersome to humans and animals due to the oscillation of inductive coils, especially in high-power applications like distributed renewable energy systems.
Innovation Solution
The implementation of a boost converter with N inductors connected to switches, where pulse width modulation (PWM) signals are provided with phases other than 360° divided by N (2π/N radians), modifying the acoustic output to reduce noise in unpleasant frequencies and increase noise in pleasant frequencies, while maintaining efficiency and ripple voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional boost converters operate at high currents and high power, then power conversion capability is improved, but acoustic noise generation increases
Solution Approach 1:
The patent divides the single inductor into multiple parallel inductors (N inductors) and divides the single switch into multiple switches. This segmentation allows the acoustic noise from individual inductors to be distributed and partially cancel out, reducing overall audible noise while maintaining the required power handling capability through parallel operation.
Solution Approach 2:
The patent employs phase-separated PWM signals to periodically switch the multiple inductors and switches at different phases. This periodic action with phase separation causes the acoustic noise waves from different inductors to interfere destructively in the audible frequency range, reducing overall noise while maintaining continuous power conversion.
2Object-generated harmful factors
If phase-separated PWM signals are used to reduce acoustic noise, then acoustic noise is reduced, but control complexity increases
Solution Approach 1:
The control system generates periodic PWM signals with specific phase separations for multiple switches. While this introduces phase control complexity, the periodic nature allows for systematic implementation using standard PWM controllers with phase-shift capabilities, making the complexity manageable through established control techniques.
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 reduces total acoustic noise in the audible range, making it less annoying and introduces a more pleasant, multi-tonal sound with little to no degradation in efficiency and ripple voltage of the DC output.
Implementation Method 1
The high currents and power flow through inductors within the boost converter and as a result, constituent inductive coils of the inductors can oscillate and thereby emanate compression waves
Implementation Method 2
Therefore, power converters and the constituent boost converter, in particular, can generate acoustic noise
Data Source
AI summary
A boost converter including two or more inductors coupled to an input DC power source and to switches that can each be modulated with a modulation signal to control the output power of the boost converter. Two or more of the modulation signals have a relative phase other than 360° divided by the number of switches.