Digital Power Converter for Induction Heating
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Solution Overview
Problem
Existing power converters for high-frequency heating equipment like microwave ovens and electromagnetic ovens are not adaptable to varying loads, as they rely on pure hardware structures and lack digital control capabilities, making them inefficient for different food types and quantities.
Innovation Solution
A digital control power converter based on a System-on-Chip (SoC) chip with integrated protection circuits, including a Micro Processing Unit (MPU), Programmable Pulse Generator (PPG), Analog-to-Digital Converter (ADC), and various detecting circuits, which dynamically adjusts the output power by changing the structure of the inductive load in the resonant circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If pure hardware circuit structures are used for power conversion, then voltage stability is improved, but power adaptability deteriorates
Solution Approach 1:
The patent combines pure hardware circuit structures with digital control units (microcontroller or DSP) to create a hybrid power converter. The hardware portion maintains voltage stability through circuit design, while the digital control portion enables power adaptability by processing load feedback and adjusting control signals dynamically. This merging resolves the contradiction by integrating both stability and adaptability functions in a unified system.
Solution Approach 2:
The patent implements feedback mechanisms where the digital control unit continuously monitors load conditions and power output, then adjusts control parameters accordingly. This closed-loop feedback enables the system to maintain voltage stability while adapting power output to different cooking utensil loads, resolving the contradiction between stability and adaptability.
2Adaptability or versatility
If digital control units are added to enable power regulation, then power adaptability is improved, but device complexity increases
Solution Approach 1:
The patent employs universal digital control units (microcontroller or DSP) that can handle multiple functions including power regulation, load detection, and protection mechanisms through software programming. This multi-functionality reduces device complexity by consolidating control tasks into a single programmable unit rather than requiring separate dedicated circuits for each function.
Solution Approach 2:
The patent replaces complex hardware control circuits with software-based control logic in digital control units. This substitution reduces device complexity by using flexible software programs instead of hardwired logic, allowing power adaptability to be achieved through algorithmic control rather than complex circuit design.
3Reliability
If peak absorption circuits are used for protection, then reliability is improved, but production cost increases
Solution Approach 1:
The patent implements protection mechanisms through digital control units that monitor system parameters and automatically take protective actions when anomalies are detected. The control unit serves the dual purpose of power regulation and protection, eliminating the need for separate peak absorption circuits. This self-service approach maintains reliability while reducing production costs by using existing control hardware for multiple functions.
Solution Approach 2:
The patent uses feedback from load detection circuits to enable the digital control unit to identify abnormal conditions and implement protection strategies. This feedback-based protection approach replaces passive peak absorption circuits with active control-based protection, improving reliability through intelligent monitoring while reducing manufacturing costs by eliminating additional protective hardware.
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
Enhances operating reliability, reduces production costs, and allows for precise power regulation in high-frequency heating equipment, improving efficiency and safety by avoiding peak absorption circuits and using comprehensive control mechanisms.
Implementation Method 1
a power inverting circuit comprising an insulated gate bipolar transistor (IGBT) and a resonant circuit consisting of an inductive load and a capacitor
Implementation Method 2
a magnetic energy conversion detecting circuit, which is used for providing an enabling output signal to the PPG
Data Source
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AI summary
A digital control type power converter for cooking utensils includes a rectifier; a power inverting circuit composed of an IGBT and an LC shunt-resonant circuit; and a SoC chip which internally integrates a MPU, a Programmable Pulse Generator (PPG), an ADC, a COM, wherein the PPG, the ADC and the COM are connected to the MPU. One output of the MPU is connected to the PPG through a first AND gate, and a pulse signal outputted by the PPG is transmitted to the IGBT through a second AND gate. The MPU calculates the present power value according to measured current and voltage signals, and compares the present power value with the required power of the host computer to change the set pulse width value of the PPG. When a magnetic energy conversion detecting circuit outputs an enabling signal, the PPG outputs the pulse signal with the setting pulse width to drive the IGBT and realize the regulation of power. Since this converter can receive man-machine operating instructions and dynamically change its output power, the inductive structure in the resonant circuit can be appropriately changed to be applied to high-frequency heating equipment, such as a microwave oven, an electromagnetic oven, and the alike.