Wireless Induction Cooker Filter Circuit for Audible Noise Blocking
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Solution Overview
Problem
Conventional induction type electric ranges generate noise due to the difference between the resonant frequency of wireless power supply and the frequency of the working coil operation falling within the audible frequency range, causing inconvenience in use.
Innovation Solution
A cooking apparatus with a receiving coil, rectifiers, DC capacitors, an inverter, and a filter circuit that blocks noise currents associated with specific frequencies, allowing the inverter to convert power into alternating current and transmit it to the working coil while minimizing noise by adjusting resonant frequencies and using a power cut-off unit controlled by a controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If wireless power supply and working coil operation use different resonant frequencies, then power transmission efficiency is improved, but noise is generated in the audible frequency range
Solution Approach 1:
A filter circuit is introduced as an intermediary component between the wireless power supply system and the working coil system. This filter circuit selectively attenuates noise components in the audible frequency range that arise from the frequency difference between the two systems, while preserving the beneficial frequency differences for power transmission efficiency.
Solution Approach 2:
The patent adjusts and optimizes the resonant frequency parameters of both the wireless power supply and working coil systems. By carefully selecting frequency values and their differences, the system maintains high power transmission efficiency while pushing the noise spectrum away from the audible range or attenuating it through the filter circuit.
2Reliability
If resonant frequency difference is within audible frequency band, then wireless power transmission can be achieved, but user convenience deteriorates due to noise
Solution Approach 1:
The filter circuit serves as a mediator that allows the wireless power transmission function to operate reliably at the required frequency difference, while simultaneously protecting the user experience by removing the harmful audible noise components. This enables both reliable power transmission and user convenience to coexist.
Solution Approach 2:
The patent converts the harmful noise effect into a benefit by using the frequency difference that initially causes noise as the basis for efficient wireless power transmission. The filter circuit then selectively removes only the audible noise portions while preserving the useful high-frequency power transmission components.
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
The solution effectively limits noise in the audible frequency band, enhancing user experience and product reliability by ensuring that the difference between resonant frequencies is within a non-audible range, thus reducing operational noise.
Implementation Method 1
a receiving coil configured to receive power wirelessly
Implementation Method 2
a first rectifier configured to rectify power transmitted from the receiving coil
Implementation Method 3
a filter circuit connected between the first DC capacitor and the second DC capacitor and configured to block a noise current that flows between the first DC capacitor and the second DC capacitor and that is associated with a predetermined frequency or a frequency higher than the predetermined frequency
Implementation Method 4
The inverter can be configured to convert power from the second DC capacitor into an alternating current and transmit the converted alternating current to the working coil
Implementation Method 5
The induction type electric range generates a strong magnetic field line by passing a high-frequency current through a working coil provided therein. For example, when the magnetic field line, which are generated by the working coil passes through a cooking tool such as a metal pot, an eddy current is formed in the cooking tool. In addition, as the eddy current flows through the cooking tool, heat is generated so that the cooking tool itself is heated
Implementation Method 6
a first DC capacitor connected to an output terminal of the first rectifier
Implementation Method 7
a second DC capacitor connected to an input terminal of the inverter
Data Source
AI summary
A cooking apparatus includes: a receiving coil configured to receive power wirelessly, a first rectifier configured to rectify power transmitted from the receiving coil, a first DC capacitor connected to an output terminal of the first rectifier, a working coil, an inverter, a second DC capacitor connected to an input terminal of the inverter, and a filter circuit connected between the first DC capacitor and the second DC capacitor and configured to block a noise current that flows between the first DC capacitor and the second DC capacitor and that is associated with a predetermined frequency or a frequency higher than the predetermined frequency. The inverter is configured to convert power from the second DC capacitor into an alternating current and transmit the converted alternating current to the working coil.