High Frequency Power Supply Snubber Circuit Harmonic Noise Reduction
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Solution Overview
Problem
High frequency power supply devices with switching circuits generate harmonic wave noise due to square or trapezoidal waveforms, which are not effectively mitigated by existing technologies, especially when zero voltage switching is not achieved.
Innovation Solution
Incorporating a high frequency power generation circuit with low-side and high-side switch elements, snubber circuits featuring capacitors and impedance elements, and diodes to smooth voltage waveforms and reduce harmonic components in the current waveform, thereby minimizing harmonic wave noise across both zero voltage switching and hard switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a switching circuit with high-side and low-side switch elements is used to generate high frequency power, then power conversion efficiency is improved, but harmonic wave noise is generated due to square or trapezoidal voltage waveforms
Solution Approach 1:
Snubber circuits are introduced as intermediary elements connected between the switch elements and the resonant circuit. These snubber circuits include capacitors and impedance elements that mediate the voltage waveform transitions, smoothing the square or trapezoidal waves generated by the switching circuit into more sinusoidal waveforms, thereby reducing harmonic wave noise while maintaining efficient power conversion
Solution Approach 2:
The patent modifies the voltage waveform parameters by using snubber circuits to change the rising and falling edges of the voltage waveform. The capacitors in the snubber circuits alter the voltage transition characteristics, transforming the abrupt square or trapezoidal waveforms into smoother waveforms with reduced high-frequency harmonic components
2Loss of energy
If zero voltage switching operation is implemented to reduce switching loss, then energy efficiency is improved, but the circuit complexity increases
Solution Approach 1:
Snubber circuits serve as intermediary elements that facilitate zero voltage switching by controlling the voltage across the switch elements during switching transitions. The capacitors in the snubber circuits ensure that the voltage across the switches reaches zero before switching occurs, enabling lossless switching without requiring complex control mechanisms
Solution Approach 2:
The snubber circuits provide beforehand cushioning by pre-charging or discharging capacitors in anticipation of switching events. This preparatory action ensures that voltage transitions occur smoothly and that switching elements operate under optimal conditions, reducing switching losses while maintaining relatively simple circuit architecture
3Object-generated harmful factors
If snubber circuits with capacitors and impedance elements are added to smooth voltage waveforms, then harmonic wave components are reduced, but device complexity increases
Solution Approach 1:
The patent divides the power conversion system into distinct functional segments: the switching circuit segment that generates high-frequency power, and the snubber circuit segment that processes and smooths the voltage waveforms. Each segment performs its specific function independently, with the snubber circuits being distributed between individual switch elements, thereby reducing harmonic wave components while maintaining manageable device complexity through modular architecture
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 proposed configuration significantly reduces harmonic wave components in the current waveform, minimizing harmonic wave noise and switching losses, while maintaining efficient power conversion and reducing electromagnetic interference.
Implementation Method 1
The low-side snubber circuit includes a series circuit including a first capacitor and a first impedance element. The high-side snubber circuit includes a series circuit including a second capacitor and a second impedance element.
Implementation Method 2
the waveform of a current flowing through a coil or an antenna connected to the output side of the switching circuit is a waveform approximated to a sine wave form, due to a resonant operation of a circuit through which the current flows
Data Source
AI summary
A switching circuit is connected to an output side of a DC power supply, includes a low-side switch circuit and a high-side switch circuit, and generates high frequency power by switching of the low-side switch circuit and the high-side switch circuit. Snubber circuits are connected between both ends of the low-side switch circuit and both ends of the high-side switch circuit. The snubber circuits include series circuits including inductors and capacitors, and include diodes that are connected in parallel with the inductors.