Quasi-Resonant Induction Hob Circuit With Voltage-Based Power Estimation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing induction cooking appliances require additional costly components for precise control of electrical operations, particularly in measuring voltage and current, which increases complexity and cost.

Innovation Solution

A quasi-resonant oscillation circuit with a resonant tank, a single switching element, and a measuring unit that estimates electrical power based on node voltage, using a voltage divider and a diode to minimize component count and cost, while adjusting switching frequency and parameters to control heating power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional measuring components (voltage and current sensors, operational amplifiers, filters) are used to precisely control electrical operations, then measurement precision and control accuracy are improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential measurement information (voltage at the first node) that is sufficient for power estimation, eliminating the need for separate current sensing components and complex measurement circuits while maintaining adequate control precision

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The voltage measurement at the first node serves multiple functions: it provides information for power estimation, resonant frequency detection, and control feedback, replacing what would traditionally require separate dedicated sensors and circuits for each function

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If additional measuring components (voltage and current sensors, operational amplifiers, filters) are used to precisely control electrical operations, then measurement precision and control accuracy are improved, but manufacturing cost increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent removes unnecessary measuring components (current sensors, operational amplifiers, filters) from the bill of materials, directly reducing component count and manufacturing cost while retaining sufficient measurement capability through voltage-only sensing

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a simple voltage divider circuit using basic resistors instead of expensive precision measurement instruments, achieving adequate measurement precision with low-cost components that simplify manufacturing

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If a single switching element and voltage divider are used to minimize component count, then device complexity and manufacturing cost are reduced, but measurement precision and control capability may deteriorate

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent makes the single voltage measurement at the first node perform multiple measurement functions simultaneously (power estimation, frequency detection, control feedback), extracting maximum information from a minimal sensor set to maintain precision without adding complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the measurement parameter from direct power measurement to voltage-based indirect measurement, using the relationship between voltage and power in the resonant circuit to achieve accurate control through simpler voltage sensing

Inventive Principle:
Principle #35Parameter changes

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 solution allows for efficient and cost-effective control of electrical operations in induction cooking appliances by reducing the need for complex measurement circuits and enabling precise power regulation with a single sensor, thereby optimizing heating performance.

Implementation Method 1

a resonant tank, in particular a resonant circuit, for generating an electrical and/or magnetic field and/or heating power

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The inductive resonant element is used to generate energy for heating a cooking vessel

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Data Source

PatentEP3982538A1Oscillation unit, induction cooking appliance and method for operating an oscillation unit
Publication Date: 2022.04.13 ELECTROLUX APPLIANCES
  • EP3982538A1 patent drawingFigure 1~2
  • EP3982538A1 patent drawingFigure 3
  • EP3982538A1 patent drawing

AI summary

The invention relates to an oscillation unit, in particular oscillation circuit (2), more in particular quasi-resonant oscillation circuit, for generating heating power for an induction cooking appliance (1), in particular for a domestic induction cooking appliance and/or an induction hob, the oscillation unit comprising a resonant tank (30), in particular a resonant circuit, for generating an electrical and/or magnetic field and/or heating power, the resonant tank (30) in particular connected to a first node (21),an, in particular single, switching element (35) connected to the resonant tank (30), in particular by the first node (21), and driven with switching signals for oscillating the resonant tank (30), a measuring unit (40) for measuring a first electrical parameter of the resonant tank (30), in particular for measuring a voltage (VCE), more in particular for measuring a node voltage (VCE) of the first node (21), and an estimating unit (45) for estimating a second electrical parameter, in particular an electrical power, of the resonant tank (30) based on the first electrical parameter, an induction cooking appliance and a method for operating an oscillation unit.