Welding Current Control via Transformer Primary Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing welding power supplies require expensive high-current sensors to measure and control the output current of welding torches, which are costly and cannot be mounted on printed circuit boards due to their size and complexity.
Innovation Solution
A constant current controller for welding applications that measures the primary current of a transformer instead of the output current at the welding torch, using an interleaved inverter arrangement to control the output current without direct sensing, allowing for cost reduction and board integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement of output current at the welding torch is used, then accurate current control is achieved, but expensive high-current sensors are required
Solution Approach 1:
The patent uses an intermediary approach by measuring the primary current of the transformer instead of directly measuring the high output current at the welding torch. The primary current serves as a mediator that is proportional to the output current but much easier and cheaper to measure accurately, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent creates a copy of the current information by measuring the primary current which contains the same control information as the output current but in a form that is easier to measure. This copying approach allows accurate current control without requiring expensive high-current sensors at the output
2Measurement precision
If high-current sensors are used to measure output current, then accurate current control is achieved, but the system becomes less portable and more expensive
Solution Approach 1:
By using the primary current as an intermediary measurement point, the system avoids the need for heavy and expensive high-current sensors at the welding torch. This intermediary approach maintains measurement accuracy while significantly improving system portability
3Reliability
If direct current measurement at the welding torch is implemented, then constant current control is achieved, but additional cables and mounting hardware are required
Solution Approach 1:
The patent extracts the current measurement function from the welding torch output and relocates it to the transformer primary side. This extraction eliminates the need for additional cables and mounting hardware at the torch while maintaining the reliability of current control through the intermediary primary current measurement
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 eliminates the need for expensive high-current sensors, reduces system costs, and enables the power supply to be more portable and adaptable for various welding processes while maintaining accurate current control.
Implementation Method 1
a transformer to transform the DC link voltage to an output voltage
Implementation Method 2
inverter circuitry, a transformer, and a filter inductor. The inverter circuitry may include a bridge rectifier
Data Source
AI summary
Systems and methods for providing a constant current controller for use in constant current welding applications are described. In one embodiment, a current controller controls the output current of the welding torch without directly measuring the output current of the welding torch. The current controller controls or sets a current in a primary winding of a transformer in an inverter of a welding power supply to control the output current of the welding torch.