Induction Cooker Diode Stress Reduction via Frequency Control
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Solution Overview
Problem
Induction heating cooking apparatuses face stress issues due to currents exceeding the rating of switches and diodes, leading to potential damage and instability.
Innovation Solution
A cooking apparatus with a controller that detects and limits the current flowing through diodes by alternately controlling switches and increasing the operating frequency when the current exceeds a predetermined value, using a current detector and signal generator to manage the current flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the current is increased to improve heating performance, then the heating efficiency is improved, but the stress on the diode exceeds its rating causing potential damage
Solution Approach 1:
The patent applies dynamics by making the switching frequency adjustable rather than fixed. The controller dynamically changes the switching frequency of the first and second switches based on real-time diode current measurements. When diode current approaches the rating value, the system automatically increases switching frequency to reduce peak current stress, thereby maintaining both high power capability and diode reliability under varying operating conditions.
Solution Approach 2:
The patent utilizes parameter changes by modifying the switching frequency parameter in response to diode current conditions. The controller monitors diode current and adjusts the switching frequency parameter to optimize performance. This parameter adjustment allows the system to maintain high heating power while keeping diode current within safe ratings, resolving the contradiction between power output and component reliability.
2Reliability
If the switching frequency is increased to reduce diode current stress, then the diode reliability is improved, but the heating efficiency may be affected
Solution Approach 1:
The patent implements feedback control by continuously measuring the actual current flowing through the diode and using this information to adjust the switching frequency. The current detector provides real-time feedback to the controller, which then modifies the switching frequency to maintain diode current below the rating value while maximizing heating power. This closed-loop feedback mechanism ensures both diode reliability and optimal heating performance are achieved simultaneously.
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 effectively reduces stress on elements by limiting currents within safe ratings, ensuring stability and independence from the size and type of cooking apparatus, thereby preventing damage and maintaining operational reliability.
Implementation Method 1
an induction heating coil to generate a magnetic field when a current is applied thereto. If the current is applied to the induction heating coil to generate the magnetic field, a secondary current is induced to the cooking vessel, and Joule heat is generated due to resistance components of the cooking vessel
Implementation Method 2
Joule heat is generated due to resistance components of the cooking vessel. Accordingly, the cooking vessel is heated by the Joule heat
Data Source
AI summary
The present disclosure relates to a cooking apparatus and a method of controlling the same, and more particularly, to a technology for reducing stress caused by a current flowing through a diode included in the cooking apparatus. The cooking apparatus includes a coil on which a vessel is mounted, configured to form a magnetic field upon application of a current; a first switch and a second switch configured to change a direction of the current flowing through the coil; a first diode connected in parallel to the first switch or a second diode connected in parallel to the second switch; and a controller configured to alternately control a turn-on operation of the first switch and the second switch, and when a maximum value of the current flowing through the first diode or a maximum value of the current flowing through the second diode exceeds a predetermined value, to increase an operating frequency of turning on the first switch and the second switch to limit the maximum value of the current flowing through the first diode or the second diode to less than or equal to the predetermined value.