Radiant Cooktop Heat Control With Thyristor and Relay Switching
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Solution Overview
Problem
Existing cooktop appliances with radiant heating elements face limitations in precise heat control and switch lifespan due to rudimentary switching methods, which hinder applications requiring consistent low heat and increase temperature amplitudes, making it difficult to employ methods like sous-vide steam cooking.
Innovation Solution
A cooktop appliance design incorporating a thyristor and relay switch, electrically coupled in series with radiant heat elements, allows for precise control of heat output by determining heating conditions based on user input signals, enabling independent activation of multiple radiant heat elements to achieve desired temperature settings without excessive cycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rudimentary switches are used to cycle radiant heating elements on and off, then heat settings can be adjusted, but the switch lifespan is limited and temperature control precision is poor
Solution Approach 1:
The patent replaces mechanical switches with electronic control circuitry including triacs, microcontrollers, and pulse width modulation (PWM) technology. This substitution eliminates mechanical wear from switching operations while enabling precise electronic control of heating element power delivery, thereby extending component lifespan and improving temperature control precision simultaneously.
Solution Approach 2:
The patent employs pulse width modulation (PWM) technique where the heating element is switched on and off at high frequency with varying duty cycles. This periodic action allows precise average power control without requiring the heating element to cycle at low frequency, which would cause temperature fluctuations and wear mechanical switches. The high-frequency switching extends switch lifespan while maintaining precise temperature control.
2Temperature
If switches are cycled frequently to maintain constant average temperature, then low heat control is achieved, but the overall lifespan of switches is limited
Solution Approach 1:
The patent replaces mechanical switches with solid-state electronic switching components (triacs, transistors) controlled by microcontrollers. These electronic components have significantly higher switching cycle lifetimes compared to mechanical switches, allowing frequent on/off cycling for temperature control without degrading switch lifespan. The electronic control system maintains consistent temperature through precise duty cycle modulation.
Solution Approach 2:
The patent uses high-frequency pulse width modulation (PWM) switching where the heating element is cycled at frequencies typically above 100Hz. This high-frequency periodic action achieves smooth average temperature control while the electronic switching components are designed to handle these cycle frequencies without degradation, unlike mechanical switches which have limited cycle lifetimes at such frequencies.
3Duration of action of stationary object
If long duty cycles are used in radiant heating elements, then switch lifespan is extended, but temperature amplitudes in food items increase
Solution Approach 1:
The patent implements high-frequency pulse width modulation (PWM) where the heating element is switched on and off at frequencies typically exceeding 100Hz. This high-frequency periodic action creates such rapid temperature fluctuations that they are effectively averaged out by the thermal mass of the food and cookware, resulting in smooth, consistent cooking temperatures. Meanwhile, the electronic switching components are designed to handle these high cycle frequencies without degradation, extending their operational lifespan.
Solution Approach 2:
The patent employs dynamic pulse width modulation where the duty cycle of the heating element can be rapidly adjusted in real-time based on temperature feedback from sensors. This dynamic control allows the system to maintain precise temperature setpoints by making small, frequent adjustments rather than relying on long, fixed duty cycles. The electronic control system responds quickly to temperature changes, preventing temperature amplitudes from developing while extending switch lifespan through controlled cycling patterns.
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 solution provides precise heat control, extends the lifespan of radiant heating elements, and allows for more consistent cooking temperatures, enhancing the ability to perform methods requiring precise temperature control like sous-vide steam cooking.
Implementation Method 1
radiant heating elements for heating pots, pans, and other containers with food items therein
Implementation Method 2
The thyristor may be operably connected to the user interface and electrically coupled in series between the power source and the first radiant heat element to control activation of the first radiant heat element
Data Source
AI summary
A cooktop appliance and method of operation is provided. The cooktop appliance may include a user interface, a power source, a burner, a thyristor, and a relay switch. The power source may be operably connected to the user interface. The burner may include a first radiant heat element and a second radiant heat element electrically coupled in parallel to the power source. The thyristor may be operably connected to the user interface and electrically coupled in series between the power source and the first radiant heat element to control activation of the first radiant heat element. The relay switch may be operably connected to the user interface and electrically coupled in series between the power source and the second radiant heat element to control activation of the second radiant heat element.