Welding Power Supply Topology With Reactive Energy Recovery
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Solution Overview
Problem
Conventional welding power supply topologies suffer from inefficiencies such as excess losses due to continuous current flow through semiconductor devices, idle transistors, and the need for additional circuitry to handle reactive energy, leading to heat loss and increased size and cost.
Innovation Solution
A welding power supply that combines rectifier and commutation functions in semiconductor devices, using a transformer with secondary windings and a control circuit to selectively output positive or negative voltages without a separate rectifier stage, and employs a reverse power transfer mode to manage reactive energy efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional full-bridge power supply circuits are used, then welding power can be supplied, but excess losses occur due to continuous current flow through semiconductor devices and idle transistors
Solution Approach 1:
The patent implements periodic switching of semiconductor devices in a half-bridge configuration, where devices are alternately activated rather than continuously conducting. This periodic action eliminates continuous current flow losses and idle transistor losses by ensuring devices are only active when needed for power transfer or reactive energy management.
Solution Approach 2:
The patent recovers reactive energy that would otherwise be lost by implementing a reverse power transfer mode. The semiconductor devices switch to conduct current in reverse direction, transferring reactive energy from the output circuit back to the input circuit, thereby recovering energy that would normally be dissipated as heat.
2Device complexity
If conventional power supply circuits with separate rectifier stages are used, then power conversion is achieved, but device complexity and size increase
Solution Approach 1:
The patent merges the rectifier stage and commutation stage into a single integrated circuit configuration. The half-bridge circuit performs both rectification and reactive energy management functions simultaneously, eliminating the need for separate rectifier stages and reducing overall device complexity.
Solution Approach 2:
The semiconductor devices in the half-bridge configuration serve multiple functions: they perform power conversion, rectification, and reactive energy transfer. This multi-functionality reduces the number of dedicated components needed, simplifying the overall circuit design and manufacturing.
3Loss of energy
If additional circuitry is added to handle reactive energy, then reactive energy management is improved, but heat loss and size increase
Solution Approach 1:
The patent recovers reactive energy by enabling reverse current flow through the transformer and semiconductor devices. This reactive energy is transferred back to the input circuit rather than being dissipated as heat, significantly reducing energy losses without requiring additional heat dissipation components.
Solution Approach 2:
The reactive energy management function is merged into the existing half-bridge circuit operation. The same semiconductor devices used for power conversion also handle reactive energy transfer by switching to reverse conduction mode, eliminating the need for separate reactive energy management circuitry and its associated heat dissipation requirements.
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 approach reduces heat loss, simplifies circuit routing, enhances thermal management, and enables a more compact design by balancing heat dissipation and efficiently managing reactive energy, while improving arc stability and reducing audio emissions.
Implementation Method 1
a transformer with secondary windings and a control circuit to selectively output positive or negative voltages
Implementation Method 2
employs a reverse power transfer mode to manage reactive energy efficiently
Data Source
AI summary
An example welding-type power supply includes: a transformer having a primary winding and first and second secondary windings; an input circuit configured to provide an input voltage to the primary winding of the transformer; first, second, third, and fourth switching elements, and a control circuit configured to: control the first, second, third, and fourth switching elements to selectively output a positive or negative output voltage without a separate rectifier stage by selectively controlling ones of the first, second, third, and fourth switching elements based on a commanded output voltage polarity and an input voltage polarity to the transformer; and prior to changing from a first output voltage polarity to a second output voltage polarity, controlling the first, second, third, and fourth switching elements to reverse the power flow to return reactive energy to an input circuit via the transformer.