Buck Converter and Steering Leg for Low-Loss Welding Power
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Solution Overview
Problem
Traditional welding power supply circuits suffer from inefficiencies due to high power losses caused by multiple transistors and diodes, which are necessary for generating high current AC outputs required for processes like GTAW and SAW, leading to a need for circuits that reduce power losses and increase efficiency.
Innovation Solution
The proposed solution involves a welding or cutting circuit with a buck converter and a steering leg, where the buck converter includes transistors and diodes configured to convert input voltage to current in an inductor, and the steering leg controls the rate of current decrease through pulse width modulation and hysteretic control, reducing power losses by optimizing current flow and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional welding power supply circuits use multiple transistors and diodes to generate high current AC outputs, then the required welding process functionality is achieved, but power losses increase and circuit efficiency decreases
Solution Approach 1:
The patent extracts and eliminates unnecessary components (transistors and diodes) from the traditional welding power supply circuit. By removing these components that contribute to power losses, the circuit achieves higher efficiency while maintaining the required high current AC output functionality through an alternative topology.
Solution Approach 2:
The patent merges the functions of multiple separate components into a unified circuit topology. Instead of using separate transistors and diodes for current control and rectification, the invention integrates these functions into a streamlined configuration that reduces component count and associated power losses.
2Productivity
If traditional welding power supply circuits use multiple transistors and diodes, then current control capability is maintained, but circuit efficiency decreases
Solution Approach 1:
The patent removes redundant transistors and diodes from the circuit, directly reducing component count and eliminating the power losses associated with these components. This extraction maintains current control capability through alternative circuit arrangements while improving overall circuit efficiency.
Solution Approach 2:
The patent changes the operational parameters and topology of the power supply circuit to achieve higher efficiency. By modifying the circuit architecture to eliminate dissipative components, the system maintains its current control functionality while operating at improved efficiency levels.
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 configuration significantly reduces power losses and increases the efficiency of the welding power supply by effectively managing current flow and direction, enabling more efficient conversion of input voltage to regulated AC outputs suitable for welding operations.
Implementation Method 1
the buck converter converts input voltage to current in an inductor coupled to the output of the buck converter
Implementation Method 2
an input leg including a capacitor coupled between a high bus and a low bus
Data Source
AI summary
Disclosed example welding or cutting circuits include: an input leg including a capacitor coupled between a high bus and a low bus; a buck converter coupled in parallel with the input leg, the buck converter having a first transistor, a second transistor, and an output electrically coupled to a node between the first transistor and the second transistor, and wherein the buck converter is configured to convert input voltage to current in an inductor coupled to the output of the buck converter; and a steering leg coupled in parallel with the input leg, wherein the steering leg is configured to control a rate at which the current in the inductor decreases, and wherein a current detector provides current level indications to a hysteretic controller, the hysteretic controller providing signals to the first and second transistors that control the first and second transistors to control the voltage applied to the inductor.