Interleaved Multiphase Converter for Arc Welder Power Source
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Solution Overview
Problem
Welding power sources face inefficiencies due to high electrical switching and conduction losses, leading to excess heat, bulkiness, and increased component count, which complicates transient response and adaptability to changing load conditions.
Innovation Solution
An interleaved multiphase switching converter is employed as a regulated final stage in a three-stage power source, featuring an unregulated DC to DC converter, allowing higher bandwidth operation without significant efficiency degradation or cost increase, reducing ripple currents and inductor sizes, and enabling advanced waveform control techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a regulated output inverter is driven by an input boost converter or DC output of a rectifier to produce current suitable for welding, then the welding current can be regulated, but electrical switching and conduction losses increase leading to excess heat and reduced efficiency
Solution Approach 1:
The welding power source is divided into three distinct stages: a regulated first stage (input boost converter), an unregulated intermediate stage, and a regulated output stage. This segmentation allows each stage to be optimized independently, with the unregulated intermediate stage handling high-current transformation without regulation overhead, thereby reducing overall switching and conduction losses while maintaining welding current regulation capability.
2Device complexity
If traditional single-phase converters are used, then the design is simpler, but the bandwidth is limited and transient response is slower
Solution Approach 1:
The patent employs a dynamic three-stage architecture where the intermediate unregulated stage can operate independently of the regulated stages, allowing the system to respond dynamically to changing load conditions. This dynamic structure enables higher bandwidth operation and faster transient response compared to traditional single-phase converters, while the modular nature maintains reasonable design complexity.
3Speed
If higher switching frequencies are used to improve transient response, then bandwidth increases, but switching losses increase and efficiency decreases
Solution Approach 1:
The regulated output stage operates at higher switching frequencies to achieve fast transient response and high bandwidth, while the unregulated intermediate stage handles the bulk of power transformation with simpler, lower-frequency operation. This partial application of high-frequency switching only where necessary minimizes overall switching losses while achieving the desired transient response performance.
4Speed
If an unregulated intermediate stage is added between the regulated first stage and output stage, then bandwidth and transient response improve, but device complexity increases
Solution Approach 1:
An unregulated intermediate stage is introduced as a mediator between the regulated input stage and regulated output stage. This intermediate stage performs high-current DC transformation without the complexity of regulation circuitry, enabling the regulated stages to operate at higher frequencies with smaller components. The intermediary simplifies the overall design by separating regulation functions from power transformation functions.
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 solution achieves improved transient response, reduced component sizes, and high efficiency, enabling advanced welding techniques with lower ripple currents and potentially unlimited bandwidth, while maintaining system cost-effectiveness.
Implementation Method 1
An interleaved multiphase switching converter is employed as a regulated final stage in a three-stage power source
Data Source
AI summary
Power sources are disclosed for electric arc welding or cutting processes, in which an interleaved multiphase switching converter is provided with a plurality of converter power circuits to convert a DC signal to a regulated signal suitable for welding.