Induction Heating Inverter Frequency Control Without Extra Sensing Circuits
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Solution Overview
Problem
Existing induction heating apparatuses require additional elements or circuits, such as shunt resistors and voltage/current sensing circuits, leading to complex configurations and increased manufacturing costs, with inaccurate power value calculations and slow control responsiveness.
Innovation Solution
An induction heating apparatus that calculates output power value using existing elements, based on DC link voltage and output current of the inverter circuit, without additional hardware, and controls the working coil through software-based adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional elements or circuits (shunt resistors, voltage/current sensing circuits) are added to control the inverter circuit, then the control accuracy and responsiveness are improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the power calculation function from hardware circuits and relocates it to software processing. The controller calculates output power by processing existing voltage and current signals through software algorithms, eliminating the need for additional shunt resistors and dedicated power sensing circuits while maintaining calculation accuracy
Solution Approach 2:
The patent replaces the mechanical/electrical hardware system (shunt resistors, sensing circuits) with a software-based calculation system. The controller uses software to process voltage and current signals and compute power values, substituting physical measurement hardware with computational methods
2Productivity
If additional elements or circuits (shunt resistors, voltage/current sensing circuits) are added to control the inverter circuit, then the control responsiveness is improved, but the manufacturing cost increases
Solution Approach 1:
The patent extracts the power calculation function from hardware circuits and relocates it to software processing. The controller calculates output power by processing existing voltage and current signals through software algorithms, eliminating the need for additional shunt resistors and dedicated power sensing circuits while maintaining calculation accuracy
Solution Approach 2:
The patent enables the controller to self-calculate power values using existing voltage and current sensing capabilities already present in the inverter circuit. The system serves its own measurement needs by processing available signals through software, eliminating dependency on additional dedicated measurement hardware
3Device complexity
If software-based calculation is used to determine output power value, then the device complexity is reduced, but the measurement precision may be affected
Solution Approach 1:
The patent implements feedback by continuously monitoring voltage and current signals and using them to calculate real-time power values. The controller adjusts the inverter circuit based on calculated power feedback, ensuring accurate power delivery while maintaining simple circuit configuration
Solution Approach 2:
The patent replaces the mechanical/electrical hardware system (shunt resistors, sensing circuits) with a software-based calculation system. The controller uses software to process voltage and current signals and compute power values, substituting physical measurement hardware with computational methods
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
Accurately calculates output power value and improves control speed and responsiveness by using software to adjust driving frequency, eliminating the need for additional hardware components.
Implementation Method 1
an alternating current may be applied to the working coil. Accordingly, an induction magnetic field may be generated around the working coil disposed in the induction heating apparatus
Implementation Method 2
an eddy current may be generated inside the bottom of the container. When the eddy current generated in this way flows through the container, the container itself may be heated
Implementation Method 3
When the eddy current generated in this way flows through the container, the container itself may be heated
Data Source
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AI summary
A method for controlling an induction heating apparatus comprises steps of receiving a power level for a heating region, supplying a switching signal to an inverter circuit based on a predetermined reference frequency, measuring an output current value of the inverter circuit, measuring a DC link voltage value, calculating an output power value of the working coil based on the output current value of the inverter circuit and the DC link voltage value, determining a heating frequency of the inverter circuit based the result of comparison by comparing the output power value of the working coil with a required power value, and supplying a switching signal to the inverter circuit based on the heating frequency.