Induction Heating Inverter Control for Abnormal Resonance Detection
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Solution Overview
Problem
Induction heating apparatuses face inefficiencies and potential damage to switching elements due to abnormal operation caused by changes in container position, leading to increased switching loss and risk of burning out the elements.
Innovation Solution
A controller measures resonance current and driving voltage values to determine the operational state of the induction heating apparatus, stopping the working coil when abnormal operation is detected and adjusting the driving frequency to prevent damage, ensuring operation within the inductive area for efficient heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the container is placed eccentrically on the upper plate, then the heating performance deteriorates and heating time increases, but the device can still operate without immediate failure
Solution Approach 1:
The controller continuously monitors the operational state of the induction heating apparatus and compares it with predetermined reference values. When the container position deviates from the optimal position, the controller detects the change in operational parameters and adjusts the driving frequency accordingly to maintain safe operation and prevent switching element damage.
Solution Approach 2:
The system dynamically adjusts the driving frequency of the working coil based on the detected operational state. When the container is in an eccentric position, the controller changes the driving frequency to a value that ensures the apparatus operates in the inductive area, thereby preventing switching element burnout while maintaining acceptable heating performance.
2Reliability
If the driving frequency is not adjusted when container position changes, then the operation remains simple, but switching elements may be burnt out due to increased switching loss
Solution Approach 1:
The controller continuously monitors the operational state of the induction heating apparatus and compares it with predetermined reference values. When the container position deviates from the optimal position, the controller detects the change in operational parameters and adjusts the driving frequency accordingly to maintain safe operation and prevent switching element damage.
Solution Approach 2:
The induction heating apparatus automatically detects changes in its operational state and adjusts its own driving frequency without external intervention. The system self-regulates to maintain operation within the inductive area, eliminating the need for manual frequency adjustment while ensuring switching element safety.
3Speed
If the working coil operates in the capacitive area, then the apparatus may operate at lower frequencies, but switching loss increases and switching elements are at risk of burning out
Solution Approach 1:
The controller continuously monitors the operational state of the induction heating apparatus and compares it with predetermined reference values. When the container position deviates from the optimal position, the controller detects the change in operational parameters and adjusts the driving frequency accordingly to maintain safe operation and prevent switching element damage.
Solution Approach 2:
The system dynamically adjusts the driving frequency of the working coil based on the detected operational state. When the container is in an eccentric position, the controller changes the driving frequency to a value that ensures the apparatus operates in the inductive area, thereby preventing switching element burnout while maintaining acceptable heating performance.
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
Prevents switching element burnout by stopping abnormal operation and adjusting frequencies, maintaining efficient power delivery and extending the lifespan of the apparatus.
Implementation Method 1
an induced magnetic field is generated around the working coil disposed in the induction heating apparatus. When magnetic line of force of the induced magnetic field generated passes through a bottom of the metallic container over the working coil, eddy current is generated inside the bottom of the container
Implementation Method 2
eddy current is generated inside the bottom of the container. Accordingly, the eddy current generated flows in the container, and the container itself is heated
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
A controller of the induction heating apparatus in one embodiment may generate an overlapped period of a resonance current value of a working coil and a driving voltage value of a switching element included in an inverter circuit. In the disclosure, the overlapped period may denote a period for which the resonance current value and the driving voltage value are all positive numbers. The controller may determine whether a driving state of the induction heating apparatus is normal or abnormal based on a time point at which the overlapped period appears. When determining that the driving state of the induction heating apparatus is abnormal, the controller may stops driving of the working coil.