Two-Quadrant Power Supply for Fast Welding Current Control
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Solution Overview
Problem
Existing welding power supplies, primarily one-quadrant power supplies, face inefficiencies in controlling output current during short circuits and pulse welding due to limited voltage reversal capabilities, leading to slow current decrease and potential voltage surges, which complicates the process and requires ineffective energy dissipation methods.
Innovation Solution
Implementing a two-quadrant power supply topology with a control system that enables unidirectional current flow and bipolar voltage, allowing operation in Q-I and Q-IV or Q-II and Q-III quadrants, using active rectifiers and pulse width modulation control to reverse output voltage and manage energy flow, thereby facilitating faster current transitions and improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a one-quadrant power supply is used for welding, then the device complexity is reduced, but the current decrease speed is slow during short circuits
Solution Approach 1:
The patent applies voltage reversal by operating in Q-I and Q-IV quadrants, where the voltage polarity is inverted while current flows in the same direction. This allows the output voltage to be reversed to force rapid current decrease during short circuits, solving the slow current decay problem of one-quadrant supplies without requiring bidirectional current capability.
Solution Approach 2:
The patent changes the operational parameters by enabling bipolar voltage output while maintaining unidirectional current flow. By switching between positive and negative voltage quadrants (Q-I and Q-IV), the system achieves fast current control through voltage reversal, transforming the single-parameter control into multi-parameter control.
2Object-affected harmful factors
If a one-quadrant power supply is used, then the energy dissipation is simplified, but voltage surges occur during current transitions
Solution Approach 1:
The patent converts the harmful effect of accumulated inductive energy into a beneficial resource by enabling Q-IV operation. When voltage is reversed in Q-IV, the energy stored in output inductors and cables is returned to the input capacitor instead of being dissipated, transforming what would be harmful voltage surges into useful energy recovery.
Solution Approach 2:
By reversing the voltage polarity in Q-IV while maintaining unidirectional current flow, the patent inverts the energy flow direction. This allows the output inductors to act as energy sources feeding back to the input capacitor, preventing voltage surges and improving energy efficiency simultaneously.
3Manufacturing precision
If a two-quadrant power supply is implemented, then the current control precision is improved, but the device complexity increases
Solution Approach 1:
The patent implements dynamic operation by enabling the power supply to switch between Q-I and Q-IV quadrants based on control signals. The PWM control system dynamically adjusts the duty cycle and switching states of power devices to achieve precise current control through voltage reversal, making the system adaptable to different welding conditions.
Solution Approach 2:
The two-quadrant topology provides multi-functionality by enabling both normal power delivery (Q-I) and voltage reversal for current control (Q-IV) within the same converter. This universal design handles various welding modes including short circuit, pulse welding, and open circuit conditions without requiring separate circuits.
4Productivity
If voltage reversal is enabled for fast current control, then the productivity is improved, but the loss of energy increases due to switching losses
Solution Approach 1:
The patent converts what would normally be wasted inductive energy into a beneficial resource by enabling Q-IV operation. During voltage reversal, the energy stored in output inductors and cables is returned to the input capacitor, transforming potential energy loss into energy recovery and improving overall system 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
This solution enables faster and more controlled current transitions during welding, reducing energy dissipation inefficiencies and minimizing voltage surges, thereby enhancing the overall efficiency and effectiveness of the power supply.
Implementation Method 1
the output inductor, inductances and resistance of cables and the welding load constitutes an energy receiver
Implementation Method 2
using active rectifiers and pulse width modulation control to reverse output voltage and manage energy flow
Data Source
AI summary
A power supply may include a power block to receive an input power and generate an output power; and a control system coupled to the power block, wherein the power block and control system are arranged to provide unidirectional current flow and bipolar voltage during operation of the power supply.