Furnace Power Supply Frequency Conversion for Arc Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supply methods for electric furnaces used in metal melting and heating processes suffer from unstable power absorption, leading to fluctuations in mains voltage and potential damage to the power supply network, as well as inefficiencies in the melting process.
Innovation Solution
The method involves transforming alternating mains voltage and current into selectively settable secondary voltage and current, which are then rectified and converted into alternating supply voltage and current. The supply frequency is dynamically regulated by a control and command unit to be lower than or equal to the mains frequency for at least 80% of the work cycle, and adjusted to values between 40% and 80% of the mains frequency in specific steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional alternating current power supply at mains frequency is used, then the furnace can operate continuously, but power losses in conductors increase and melting efficiency decreases
Solution Approach 1:
The patent applies parameter changes by transforming the mains frequency (typically 50-60 Hz) to a lower secondary frequency (e.g., 25-30 Hz) through frequency conversion. This frequency parameter change reduces skin effect and proximity effect in conductors, thereby reducing power losses while improving melting efficiency through more effective current distribution
2Loss of energy
If the supply frequency is reduced to improve efficiency, then power losses decrease, but the arc stability may be affected
Solution Approach 1:
The patent applies dynamics by implementing dynamic frequency regulation that adapts the supply frequency to different operational phases of the furnace. During boring operations, a different frequency is used compared to melting operations, optimizing both arc stability and energy efficiency for each specific phase through real-time parameter adjustment
3Reliability
If continuous regulation of electrode position and power parameters is implemented, then power supply stability improves, but device complexity increases
Solution Approach 1:
The patent applies feedback by implementing a control system that continuously monitors power absorption, arc voltage, and current parameters, then automatically adjusts electrode position and power supply parameters accordingly. This closed-loop feedback mechanism stabilizes power supply while managing system complexity through intelligent control algorithms
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 power losses in conductors, improves heat exchange and temperature uniformity in the molten bath, and decreases the overall power required for the melting process, thereby enhancing the efficiency and stability of the electric arc.
Implementation Method 1
a transformer connected to power supply means that supply an alternating mains voltage and mains current, both having a predefined mains frequency, the transformer being configured to transform the mains voltage and the mains current respectively into an alternating secondary voltage and secondary current
Implementation Method 2
a plurality of rectifiers connected to the transformer and configured to transform the alternating secondary voltage and secondary current into direct electric voltage and current
Implementation Method 3
a plurality of converters connected to the rectifiers and configured to convert the direct electric voltage and current into an alternating supply voltage and supply current, the converters being connected to electrodes of the furnace
Implementation Method 4
generating the electric arc, during which the electrodes are lowered toward the metal material until the melting electric arc is triggered, which is generated between the ends of the electrodes and the material to be melted
Data Source
AI summary
The invention concerns a method to supply electric power to furnaces (100) for melting and/or heating metal materials (M), which provides the supply of a mains voltage (Ur) and a mains current (Ir), both having a predefined mains frequency (fr); the transformation of said mains voltage (Ur) and mains current (Ir) into selectively settable alternating secondary voltage (Us) and secondary current (Is); the rectifying of said secondary voltage (Us) and secondary current (Is) and the conversion of the direct intermediate voltage (Ui) and intermediate current (Ii) into selectively settable alternating supply voltage (Ua) and supply current (Ia); the feeding of said supply voltage (Ua) and supply current (Ia) to a plurality of electrodes (102) of the furnace (100). The invention also concerns an apparatus (10) for supplying electric power to furnaces (100) for melting and/or heating metal materials (M).