Induction Cooktop Current Sensor with Antiserial Inductances

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Solution Overview

Problem

Existing induction cooktops face challenges in accurately measuring high-frequency currents due to interference from other electric and magnetic fields, which affects measurement accuracy and requires complex structures and higher costs.

Innovation Solution

A cooking appliance apparatus with a current sensor unit featuring two sensor inductances connected in an antiserial manner, where one sensor inductance cancels out the magnetic field of the other, enhancing shielding capacity and measurement accuracy while maintaining a simple structure and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single sensor inductance is used to measure high-frequency current, then the structure remains simple, but measurement accuracy deteriorates due to interference from external electric and magnetic fields

Engineering Contradiction:

Improvecurrent measurement accuracyVSAvoidinterference from external fields

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The single sensor inductance is divided into two separate sensor inductances (first sensor inductance and second sensor inductance). Each inductance is positioned to detect magnetic fields from different directions, allowing the system to segment the measurement function and cancel out external interference through differential measurement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The two sensor inductances are configured with opposite winding directions so that they generate opposing magnetic fields. This preliminary anti-action arrangement allows the sensor unit to inherently cancel out external magnetic field interference before it affects the measurement, by ensuring that external fields induce equal and opposite voltages in the two inductances.

Inventive Principle:

Principle #9Preliminary anti-action

2Measurement precision

If shielding structures are added to protect against external fields, then measurement accuracy improves, but device complexity increases

Engineering Contradiction:

Improvecurrent measurement accuracyVSAvoidsensor unit structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of adding external shielding structures to protect the sensor, the patent extracts the interference cancellation function into the sensor inductances themselves. The two inductances are configured to inherently reject external fields through their opposing orientations, removing the need for additional shielding components and keeping the structure simple.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful effect of external magnetic fields into a beneficial cancellation mechanism. By positioning the two sensor inductances with opposite winding directions, external fields that would normally cause interference instead induce equal and opposite voltages that cancel each other out, turning the interference source into a self-correcting mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If complex shielding measures are implemented to reduce external field interference, then measurement reliability improves, but manufacturing costs increase

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive complex shielding structures with simple, inexpensive sensor inductances that provide interference rejection through their configuration. The two inductances can be implemented using standard PCB traces or simple wire windings, significantly reducing manufacturing costs while maintaining measurement reliability through the differential measurement principle.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 configuration improves current measurement accuracy, reduces interference from external fields, and simplifies the structure, leading to more reliable and cost-effective high-frequency current measurement in induction cooktops.

Implementation Method 1

a first sensor inductance (14a, 14b, 14c), which is provided to generate a first magnetic field, and at least one second sensor inductance (16a, 16b, 16c), which is provided to generate a second magnetic field, which opposes the first magnetic field

Methodology Applied

Scientific EffectMagnetic field cancellation: Magnetic Field

Implementation Method 2

a current sensor unit (10a, 10b, 10c), which is provided to measure a high-frequency current

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10412790B2Cooking appliance

Publication Date: 2019.09.10 BOSCH SIEMENS HAUSGERATE GMBH

AI summary

A cooking appliance apparatus includes at least one current supply line, and at least one current sensor unit configured to measure a high-frequency current in the at least one current supply line. The at least one current sensor has a first sensor inductance, at least one second sensor inductance, and at least one conduction path, which connects the first sensor inductance to the at least one second sensor inductance in an electrically conducting manner.