SiC Inverter for Plasma Cutting Power Supply
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Solution Overview
Problem
High-power plasma cutting power supplies are bulky, inefficient, and prone to reliability issues due to high voltage spikes and transient current surges, limiting the improvement of cutting quality and industrial production.
Innovation Solution
An SiC inverted plasma cutting power supply with a main circuit and closed-loop control circuit, utilizing SiC power devices for high-frequency operation, noise suppression, and advanced protection modules to achieve efficient energy transfer and refined control of cutting current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rectification or chopping based plasma cutting power supply is used for medium and high power, then reliability is improved, but device size increases and energy efficiency decreases
Solution Approach 1:
The patent changes the operating frequency parameter from traditional low frequency (50/60Hz) to high frequency (20kHz-100kHz) by using SiC MOSFETs with fast switching capability. This parameter change enables the use of smaller transformers and filters while maintaining reliability, directly resolving the contradiction between reliability and device size.
Solution Approach 2:
The patent replaces traditional mechanical/chopping-based power conversion with electronic switching using SiC MOSFETs. This substitution enables more efficient energy conversion with reduced physical size of magnetic components, addressing both reliability and size concerns simultaneously.
2Ease of manufacture
If Si-based power rectifier diode is used, then manufacturing cost is reduced, but voltage spikes occur and reliability deteriorates
Solution Approach 1:
The patent employs SiC (silicon carbide) material for power devices, which combines the benefits of wide bandgap semiconductor properties. SiC MOSFETs and SiC Schottky diodes provide both fast switching for efficiency and inherent protection against voltage spikes, resolving the contradiction between manufacturing cost and reliability through superior material properties.
Solution Approach 2:
The patent converts the previously harmful reverse recovery effect into a beneficial feature by using SiC Schottky diodes that exhibit negligible reverse recovery. This eliminates voltage spikes and EMI issues while maintaining cost-effectiveness, turning a potential problem area into a reliability strength.
3Power
If high no-load voltage is used for plasma arc cutting, then cutting capability is improved, but transient current surge occurs and reliability decreases
Solution Approach 1:
The patent implements preliminary arc ignition using a high-frequency oscillator circuit that generates a leading arc before main power delivery. This preliminary action prevents sudden current surges when establishing the plasma arc, allowing high no-load voltage to be used safely for improved cutting capability without reliability penalties.
Solution Approach 2:
The patent uses RC snubber circuits and TVS diodes placed across power switches to provide beforehand cushioning against voltage spikes and current surges. These protective elements absorb transient energy before it can damage components, enabling high power operation with maintained reliability.
4Device complexity
If low inverting frequency is used, then device complexity is reduced, but energy efficiency decreases and dynamic characteristics worsen
Solution Approach 1:
The patent increases the inverting frequency from traditional low frequency to high frequency (20kHz-100kHz) using SiC MOSFETs. This parameter change reduces switching losses and improves energy efficiency while the modular design keeps device complexity manageable, resolving the contradiction between complexity and efficiency.
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 SiC power supply achieves high energy efficiency, improved reliability, and enhanced cutting quality with reduced size and weight, capable of stable operation across low and high power applications, and lower manufacturing costs.
Implementation Method 1
utilizing SiC power devices for high-frequency operation
Implementation Method 2
noise suppression module
Implementation Method 3
power-frequency rectification and filtering module
Implementation Method 4
power transformer
Implementation Method 5
SiC rectifier diodes
Implementation Method 6
capacitors
Implementation Method 7
inductor
Implementation Method 8
non-contact arc initiation module
Data Source
AI summary
The present invention provides an SiC inverted plasma cutting power supply, which is characterized in that: the SiC inverted plasma cutting power supply comprises a main circuit and a closed-loop control circuit; the main circuit comprises a sequentially connected noise suppression module, a power-frequency rectification and filtering module, an SiC inverter module, a power transformer, an SiC rectification and smoothing module and a non-contact arc initiation module, wherein the noise suppression module is connected to an alternating-current input power supply, and the SiC rectification and smoothing module and the non-contact arc initiation module are respectively connected to a load; the closed-loop control circuit comprises a man-machine interaction module, a DSC controller, a failure diagnosis and protection module, an SiC high-frequency drive module and a load electrical signal detection module. The power supply has high inverting frequency, small size, light weight, lower raw material consumption, high energy efficiency, an obvious energy saving effect and excellent dynamic characteristics, and can be applied on both a low-power occasion and medium and high power cutting occasions in a stable and reliable manner.