Power Supply Apparatus Using Feedback Control to Prevent Transformer Saturation
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Solution Overview
Problem
Existing power supply apparatuses for arc-utilizing devices face issues with size, weight, and cost due to the need for transformers with excessive magnetic saturation margins to handle unstable commercial AC power, leading to inefficient power delivery.
Innovation Solution
A power supply apparatus with feedback control mechanisms using detection signals to manage the switching operation of the transformer, preventing magnetic saturation by maintaining a constant VT product, allowing for compact, lightweight, and cost-effective transformer design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transformer with a magnetic saturation characteristic having some margin is employed to handle unstable commercial AC power supply voltage, then the transformer can avoid magnetic saturation, but the size and weight of the power supply apparatus increase
Solution Approach 1:
The invention employs feedback control by detecting the input voltage to the transformer and adjusting the switching duty ratio accordingly. When the input voltage increases, the duty ratio is reduced to prevent the transformer core from saturating. This active control mechanism replaces the need for an oversized transformer with built-in margin, allowing the use of a compact transformer while maintaining reliability.
Solution Approach 2:
The invention changes the operating parameters of the transformer dynamically by adjusting the switching duty ratio based on input voltage conditions. By modifying the duty ratio parameter in response to voltage fluctuations, the system maintains the transformer operating point within the linear region, preventing saturation without requiring excessive transformer capacity margin.
2Reliability
If a transformer with a magnetic saturation characteristic having some margin is employed to handle unstable commercial AC power supply voltage, then the transformer can avoid magnetic saturation, but the cost of the power supply apparatus increases
Solution Approach 1:
The feedback control system monitors input voltage and adjusts the switching duty ratio to prevent transformer saturation. This control-based solution replaces the need for an expensive oversized transformer, reducing material costs while maintaining the same level of reliability against voltage fluctuations and saturation.
Solution Approach 2:
By dynamically adjusting the switching duty ratio parameter, the system optimizes transformer utilization and avoids the need for costly margin capacity. This parameter control approach allows the use of a smaller, more cost-effective transformer while maintaining reliable operation under varying input conditions.
3Power
If the commercial AC power supply voltage increases much, then the power supply ability is improved, but the core of the transformer becomes saturated and appropriate power can no longer be supplied to the load
Solution Approach 1:
The feedback control system detects increased input voltage and responds by reducing the switching duty ratio. This prevents the transformer core from saturating even when high input voltage is applied, maintaining stable and reliable transformer operation across the full range of input voltage conditions while still utilizing the available power.
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
The solution ensures stable power delivery to arc loads by preventing transformer saturation, reducing the size and weight of the apparatus while maintaining efficient operation across varying commercial power supply voltages.
Implementation Method 1
converting means for converting the supplied AC power to DC power
Implementation Method 2
the resultant rectified voltage is applied to a smoothing capacitor
Implementation Method 3
the resulting DC power is then converted to high-frequency power through the switching operation of switching means
Implementation Method 4
The voltage of the high-frequency power is voltage-transformed by a transformer
Implementation Method 5
The voltage-transformed high-frequency power is rectified by rectifying means, whereby output power is provided
Data Source
AI summary
A rectifying circuit (18) converts inputted AC power to DC power. An inverter circuit (22) converts the DC power to high-frequency power in accordance with a switching control signal applied thereto from a control circuit (50). A voltage transformer (24) voltage-transforms the voltage of the high-frequency power. An output-side rectifying circuit (40) rectifies the voltage-transformed power. An output detecting circuit (34) detects the magnitude of the voltage of the rectified power, and a signal representative of the detected voltage is applied to the control circuit (50). The control circuit (50) generates such a switching control signal as to make the rectified power have a predetermined value. The value of the voltage from the rectifying circuit (18) is detected by an input detecting circuit (62), and a signal representative of the detected voltage is applied to the control circuit (50). The control circuit (50) controls the operation of the inverter circuit (22) in accordance with the detected voltage representative signal from the input detecting circuit (62) and the saturation magnetic characteristic of the voltage-transformer (24).