Induction Heating Phase Angle Control for Mutual Induction
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Solution Overview
Problem
Conventional induction heating methods with multiple heating coils face challenges in stable operation due to mutual induction, leading to poor power factor and increased switching losses, making rapid response and efficient control difficult.
Innovation Solution
The method employs self-resonant circuits with a resonant high-frequency power supply to equalize phase angles between reactance and resistance components of mutual induction impedance, and adjusts frequency and current values to minimize phase differences between output current and voltage, using reverse coupling inductance to reduce phase angles and achieve zero voltage or current switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current synchronization control is performed using conventional methods with large pulse movement range, then current synchronization is achieved, but rapid response and stable control are compromised
Solution Approach 1:
The patent changes the control parameter from large pulse movement range to small phase angle adjustment range. By controlling the phase angle between coil currents within a small range and adjusting the frequency and current values, the system achieves both stable synchronization and rapid response without the need for large pulse movements.
Solution Approach 2:
The patent introduces dynamic adjustment of frequency and current values to maintain stable phase angles under varying conditions. The control system continuously adapts these parameters to keep the phase angle between coil currents small, enabling rapid response while maintaining synchronization stability.
2Reliability
If mutual induction voltage of reactive part is high, then current synchronization is maintained, but power factor deteriorates and inverter capacity increases
Solution Approach 1:
The patent changes the operating parameters of the induction heating system by controlling the phase angle between coil currents and adjusting frequency and current values. This reduces the mutual induction voltage of the reactive part, improving power factor and reducing required inverter capacity while maintaining synchronization.
Solution Approach 2:
The patent converts the harmful effect of mutual induction into a beneficial control mechanism. By deliberately controlling the phase angle between coil currents, the system utilizes mutual induction to achieve synchronization while minimizing its negative effects on power factor and inverter capacity.
3Device complexity
If phase angle between coil currents is not controlled, then control complexity is reduced, but power sharing between inverters becomes unstable
Solution Approach 1:
The patent simplifies control by changing from complex pulse position control to phase angle control with small adjustment ranges. By controlling the phase angle between coil currents and adjusting frequency and current values, the system achieves stable power sharing with simpler control logic.
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 enables stable, high-efficiency, rapid-response induction heating with a high power factor, reducing phase variations and switching losses, and allowing for uniform heating under mutual induction conditions.
Implementation Method 1
since a heating method using induction heating utilizes electromagnetic induction
Implementation Method 2
as a means for performing rapid heating, induction heating is effective
Implementation Method 3
adjustment or control is performed such that a phase angle between a reactance component and a resistance component of a mutual induction impedance and a phase angle between a reactance component and a resistance component of an impedance in the self-resonant circuit are made equal to each other
Data Source
AI summary
An object is to provide an induction heating method having a high power factor in which when thermal processing is performed through a plurality of heating coils receiving the supply of the current to generate mutual induction. In an induction heating method using an induction heating device that includes self-resonant circuits which feeds currents of equal frequency to a plurality of heating coils receiving the supply of the current to generate mutual induction is connected, wherein adjustment or control is performed to carry out an operation such that a first ratio of a reactance component of a mutual induction impedance to a resistance component of the mutual induction impedance between the adjacent self-resonant circuits and a second ratio of a reactance component of a self-impedance to a resistance component of the self-impedance in the self-resonant circuit are made equal to each other.