Microwave Oven Duty Cycle Control for Wireless Interference

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Solution Overview

Problem

Microwave ovens interfere with wireless communication signals due to the same frequency band used for microwave generation, causing interference that disrupts communication links with routers or other devices.

Innovation Solution

Implementing a control unit that manages the microwave generator using a duty cycle to alternate between active and inactive periods, allowing for interference-free wireless communication by pausing microwave generation during data transmission/reception, while maintaining power control and adapting the duty cycle to communication needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the microwave generator operates continuously at high power, then cooking performance is improved, but wireless communication is disrupted due to interference in the 2.4 GHz frequency band

Engineering Contradiction:
Improvecooking performanceVSAvoidwireless communication reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The microwave generator operates in periodic cycles with active phases for cooking and inactive phases for wireless communication. The control unit schedules microwave generation to occur during intervals when wireless communication is not occurring, allowing both functions to operate effectively without continuous interference.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the duty cycle of the microwave generator based on communication requirements. The control unit modulates the microwave power delivery in real-time, switching between high-power cooking modes and low-power or zero-power communication modes to balance cooking performance with communication reliability.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the microwave generator is deactivated frequently for communication, then wireless communication reliability is improved, but cooking efficiency deteriorates

Engineering Contradiction:
Improvewireless communication reliabilityVSAvoidcooking efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

Instead of completely deactivating the microwave generator during communication periods, the system uses partial power levels or reduced duty cycles that maintain sufficient cooking progress while allowing communication. The control unit optimizes the balance by applying just enough microwave energy to continue cooking without causing interference.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The control unit changes operational parameters of the microwave generator, such as power level, pulse width, and duty cycle, to accommodate communication requirements. By adjusting these parameters dynamically, the system maintains cooking efficiency while creating windows for reliable wireless communication.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the duty cycle ratio favors long active periods, then cooking performance is maintained, but communication opportunities are reduced

Engineering Contradiction:
Improvecooking performanceVSAvoidcommunication time availability
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The control unit plans and schedules communication activities in advance during the duty cycle, allocating specific time slots for wireless communication before they are needed. This preliminary scheduling ensures that communication opportunities are preserved without compromising overall cooking performance, as the system anticipates and prepares for communication requirements ahead of time.

Inventive Principle:
Principle #10Preliminary action

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

Enables reliable, interference-free wireless communication and power control within the microwave oven, even at maximum power levels, by pulsing the microwave generator, thus balancing cooking and communication operations without compromising cooking performance.

Implementation Method 1

Microwaves used in microwave ovens to heat food often have a frequency of 2.4 to 2.5 GHz. The electromagnetic waves produce oscillating magnetic and electric fields that excite water molecules in food, therefore generating heat.

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

The electromagnetic waves produce oscillating magnetic and electric fields that excite water molecules in food, therefore generating heat.

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 3

Short-range wireless communication, specifically WIFI-communication, is also performed in the frequency band of 2.4 GHz to 2.5 GHz.

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP3768045B1Microwave oven
Publication Date: 2023.06.07 ELECTROLUX APPLIANCES
  • EP3768045B1 patent drawingFigure 1~2
  • EP3768045B1 patent drawingFigure 3~4
  • EP3768045B1 patent drawingFigure 5

AI summary

The invention relates to a microwave oven comprising at least one microwave generator (2) and a control unit or control entity (3) for controlling said microwave generator (2), wherein said control unit or control entity (3) is configured to control the microwave generator (2) according to a duty cycle in which the microwave generator (2) is activated in a first time period (T1) of the duty cycle and deactivated in a second time period (T2) of the duty cycle, wherein the microwave oven (1) further comprises a wireless communication unit or communication entity (4), wherein said wireless communication unit or communication entity (4) is controlled by said control unit or control entity (3) in order to perform wireless communication in the second time period (T2) of the duty cycle.