Electromagnetic heating system and control method and device thereof
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Solution Overview
Problem
Existing electromagnetic heating systems face issues with high pulse currents during low power heating, which can damage components and affect cooking performance, especially in intermittent heating modes like congee cooking.
Innovation Solution
A method and device that control the electromagnetic heating system by driving the power switch transistor through distinct voltage stages - amplification, saturation, and off states - within each control period, using a first driving voltage in the discharging stage to restrain pulse currents and achieve low power heating with a millisecond-level duty ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low power heating is used with conventional resonance parameters, then energy consumption is reduced, but pulse current exceeds the use threshold of the IGBT which may damage the component
Solution Approach 1:
The patent applies dynamics by making the resonance parameters adjustable rather than fixed. The control unit dynamically changes the resonance parameters based on the target power level, allowing the system to adapt to different power requirements while maintaining component safety. Specifically, when low power heating is required, the control unit adjusts the resonance parameters to prevent excessive pulse currents, thus protecting the IGBT while enabling energy-efficient operation.
Solution Approach 2:
The patent implements parameter changes by modifying the resonance parameters according to the target power level. The control unit receives a target power instruction and adjusts the resonance parameters accordingly - when the target power is below a threshold, different resonance parameters are applied compared to when it is above the threshold. This parameter adjustment ensures that pulse currents remain within safe limits for the IGBT across all power levels while achieving the desired heating effect.
2Use of energy by moving object
If duty ratio mode is used for low power heating, then energy consumption is reduced, but intermittent heating affects cooking function such as causing overflow when making congee
Solution Approach 1:
The patent uses dynamics to transition from intermittent duty ratio heating to continuous heating by dynamically adjusting the resonance parameters. Instead of switching the heating on and off, the control unit continuously adjusts the resonance parameters to match the target power level, maintaining continuous heating operation. This dynamic parameter adjustment achieves energy reduction while preserving the continuous heating function needed for cooking applications like making congee.
Solution Approach 2:
The patent applies parameter changes by modifying the resonance parameters based on the target power level rather than using duty ratio control. When low power heating is needed, the control unit changes the resonance parameters to achieve the desired power output through continuous operation. This parameter-based control maintains continuous heating, preventing issues like overflow during cooking while still reducing energy consumption compared to high power operation.
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 effectively reduces pulse currents and enables low power heating without damaging the power switch transistor, improving user experience by maintaining efficient cooking performance.
Implementation Method 1
an electromagnetic resonance circuit with a single IGBT usually adopts a parallel resonance mode
Implementation Method 2
when the IGBT is switched on due to the matching of the resonance parameters... the leading voltage of the IGBT is very small and a pulse current of the IGBT is very small
Data Source
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AI summary
The present disclosure discloses a method for controlling an electromagnetic heating system, including: obtaining a target heating power of the electromagnetic heating system; determining whether the target heating power is less than a preset power; and when the target heating power is less than the preset power, controlling, in each control period, a resonance circuit of the electromagnetic heating system to enter into a discharging stage, a heating stage, and a stop stage successively, in which in the discharging stage, a power switch transistor of the resonance circuit is driven by a first driving voltage such that the power switch transistor works in an amplification state. In this way, a pulse current of the power switch transistor may be restrained, and a low power heating is realized by using a heating mode with a millisecond duty ratio. The present disclosure further discloses a device for controlling an electromagnetic heating system and an electromagnetic heating system.