Induction Heating Power Supply Phase Synchronization
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Solution Overview
Problem
Existing electric power systems for induction heating and melting in susceptor vessels face challenges with mutual inductive coupling between multiple induction coils, particularly as materials transition from non-electrically conductive to electrically conductive states, affecting power supply outputs and heating efficiency.
Innovation Solution
The system provides separate alternating current power supplies to each induction coil surrounding a susceptor vessel, with phase-synchronized output voltages and adjustable power magnitudes to maintain efficient heating and optional phase shifts for unidirectional stirring of molten materials, transitioning from susceptor inductive heating frequencies to molten material frequencies as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate power supplies are provided to each induction coil, then heating efficiency is improved, but mutual inductive coupling between coils adversely affects power supply outputs
Solution Approach 1:
The patent implements feedback control by monitoring the actual output of each power supply and adjusting the drive signals accordingly. The control circuit detects changes in mutual inductance effects and compensates by modifying the power supply outputs to maintain stable heating performance despite coupling between coils.
Solution Approach 2:
The system dynamically changes operating parameters including frequency and amplitude of power supply outputs based on the state of the material being processed. As the material transitions from solid to molten state, the system adjusts parameters to optimize heating while compensating for mutual inductance effects.
2Manufacturing precision
If multiple induction coils surround different zones of the susceptor vessel, then heating uniformity is improved, but mutual inductance changes as material melts affecting processing control
Solution Approach 1:
The patent employs dynamic control where the system continuously adapts to changing conditions during the melting process. The control circuit adjusts power distribution to each coil in real-time based on detected material state changes, maintaining processing control despite varying mutual inductance conditions.
Solution Approach 2:
The system divides the heating process into multiple zones using separate induction coils, each independently controlled. This segmentation allows differential heating of different regions while the control system coordinates the coils to maintain overall processing control despite mutual inductance coupling.
3Stability of the object's composition
If phase synchronized output voltages are provided to induction coils, then heating consistency is improved, but flexibility for unidirectional stirring is reduced
Solution Approach 1:
The system employs periodic action by enabling phase shift between coil outputs to create rotating magnetic fields for stirring. When stirring is required, the control circuit introduces phase differences that generate unidirectional rotation of the magnetic field, providing flexibility while maintaining consistent heating through coordinated multi-coil operation.
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 ensures consistent and efficient heating and melting of materials by minimizing the impact of mutual inductance changes and achieving controlled electromagnetic stirring, optimizing power distribution and material processing in susceptor vessels.
Implementation Method 1
Alternating current from each of the separate power supplies flowing through the induction coils generates the magnetic fields that inductively couple either with the susceptor or the material in the vessel
Implementation Method 2
A material that is non-electrically conductive in the solid state and electrically conductive in the molten state, such as silicon, can be heated in a susceptor vessel by placing the material in the susceptor vessel in the solid state and inductively heating the susceptor vessel
Implementation Method 3
Heat transfer from the heated susceptor to the solid state material in the vessel will heat and begin to melt the material to its electrically conductive molten state
Implementation Method 4
The generated magnetic fields also create a mutual inductance between the two or more induction coils
Implementation Method 5
Optional phase shift adjustments of the output voltages of the power supplies can be provided after all transition material in the susceptor vessel has been melted to achieve unidirectional stirring of the molten material in the susceptor vessel
Data Source
AI summary
Apparatus and process for heating and melting a material in a susceptor vessel are provided wherein phase synchronized ac voltage is supplied from a separate power source to each one of at least two induction coils in separate zones around the vessel. Power magnitude from each source to an induction coil is controlled by pulse width control of the source's output voltage. Output frequency from each source is either fixed or variable based upon the electrically conductive state of the material. Optional electromagnetic stirring is achieved by establishing a phase shift between the voltage outputs of the power supplies after the material in the susceptor vessel has melted.