Induction Heating Control Circuit Polarity-Based Delay Adjustment
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Solution Overview
Problem
Existing heating control systems for induction cooking devices lack efficient methods to dynamically adjust the activation time of the induction coil, leading to inefficiencies in energy use and potential overheating, which can result in electromagnetic noise and component degradation.
Innovation Solution
A system and method that utilize a drive circuit with first and second switching circuits, a sensing circuit to detect coil current polarity, and a control circuit to adjust the delay between activation signals based on the polarity, ensuring efficient energy use and reduced activation time by aligning deactivation with energy dissipation periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the induction coil is activated continuously to maintain heating, then the heating function is reliable, but energy is wasted and thermal dissipation increases
Solution Approach 1:
The patent implements periodic action by using pulse-width modulation (PWM) to switch the induction coil between active and inactive states. The controller dynamically adjusts the duty cycle of these periodic cycles, activating the coil only when heating is needed and deactivating it during energy dissipation periods, thus eliminating continuous activation while maintaining heating reliability.
Solution Approach 2:
The patent employs feedback mechanisms where sensing circuits monitor coil current polarity and magnitude, and temperature sensors detect heating status. This feedback information is fed back to the controller, which adjusts the activation timing and duration accordingly, ensuring the coil is activated only when necessary and deactivated during energy dissipation periods.
2Productivity
If the activation time of the induction coil is extended to ensure adequate heating, then heating effectiveness improves, but electromagnetic noise increases and components degrade
Solution Approach 1:
The patent applies dynamics by making the activation time adjustable rather than fixed. The controller dynamically modifies the pulse width and duty cycle based on real-time feedback from sensing circuits and temperature sensors, optimizing the activation duration to achieve adequate heating while minimizing electromagnetic noise and component stress.
Solution Approach 2:
The patent utilizes parameter changes by varying the activation time, duty cycle, and power level parameters of the induction coil based on feedback from sensing circuits. The controller adjusts these parameters dynamically to match actual heating needs, preventing excessive activation that would generate electromagnetic noise and accelerate component degradation.
3Speed
If the delay between activation signals is reduced to improve response speed, then system responsiveness improves, but unnecessary energy conversion and thermal dissipation increase
Solution Approach 1:
The patent uses feedback from sensing circuits that monitor coil current polarity and magnitude to determine the optimal delay between activation signals. The controller waits for the coil current to complete its natural cycle and reach zero-crossing points before activating the next pulse, ensuring minimal delay that prevents unnecessary energy conversion and thermal dissipation while maintaining fast response.
Solution Approach 2:
The patent ensures continuity of useful action by timing the activation signals to coincide with natural zero-crossing points of the coil current waveform. This synchronization ensures that activation occurs at the most efficient moment in the current cycle, maintaining continuous useful heating action while minimizing energy waste from premature or excessive activation.
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 enhances thermal and electrical efficiency by reducing unnecessary energy conversion and thermal dissipation, improving the reliability of the heating assembly and minimizing electromagnetic noise.
Implementation Method 1
at least one induction coil
Implementation Method 2
heating assembly for a cooking appliance includes at least one induction coil
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A heating assembly for a cooking appliance includes at least one induction coil (16). A drive circuit (18) is configured to control a coil current (60) through the at least one induction coil (16). The drive circuit (18) includes a first switching circuit (34) operable to conduct the coil current (60) and a second switching circuit (36) operable to conduct the coil current (60). A sensing circuit (20) is configured to detect a polarity of the coil current (60). A control circuit (22) is configured to communicate a first activation signal to the first switching circuit (34) during a first activation period. The control circuit (22) is further configured to communicate a second activation signal to the second switching circuit (36) during a second activation period. The control circuit (22) is further configured to control a delay between the first activation signal and the second activation signal based on the polarity of the coil current (60).