Dynamic Magnetron Control for Consistent Power Output
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Solution Overview
Problem
Microwave ovens experience inconsistency in power output when the magnetron is cycled at less than 100% power due to varying tube start times, leading to inefficiencies as the tube ages and during short cook cycles.
Innovation Solution
A dynamic time base is implemented using a non-linear algorithm to adjust the cycle time and on-time of the magnetron based on the required power level and tube start time, ensuring consistent power delivery by measuring current to the magnetron power supply and employing a polynomial to maintain reasonable cycle times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the magnetron is cycled on and off to lower power levels, then power consumption is reduced, but power output consistency deteriorates due to varying tube start times
Solution Approach 1:
The patent applies dynamics by making the time base adjustable rather than fixed. The controller dynamically modifies the time base parameter based on detected tube start time variations, allowing the cycling schedule to adapt to changing tube conditions. This resolves the contradiction by enabling power reduction through cycling while maintaining consistent power output despite variations in tube start time.
Solution Approach 2:
The patent implements feedback by monitoring the actual tube start time and using this information to adjust the time base for subsequent cycling operations. The controller detects when the tube actually starts conducting and uses this measured data to refine future timing, creating a closed-loop system that maintains power consistency while allowing energy-efficient cycling.
2Device complexity
If a fixed time base is used for magnetron cycling, then device complexity is reduced, but power consistency worsens as tube start time varies with aging
Solution Approach 1:
The patent applies dynamics by making the time base adjustable rather than fixed. The controller dynamically modifies the time base parameter based on detected tube start time variations, allowing the cycling schedule to adapt to changing tube conditions. This resolves the contradiction by enabling power reduction through cycling while maintaining consistent power output despite variations in tube start time.
Solution Approach 2:
The patent applies self-service by having the system automatically detect and compensate for its own aging characteristics. The tube's changing start time is automatically measured and the controller self-adjusts the time base without external intervention, allowing the system to maintain reliability throughout the tube's lifecycle without requiring manual recalibration or complex external control systems.
3Stability of the object's composition
If the time base is extended to accommodate long tube start times, then power consistency is improved, but productivity decreases due to excessive cycling duration
Solution Approach 1:
The patent applies dynamics by making the time base adjustable rather than fixed. The controller dynamically modifies the time base parameter based on detected tube start time variations, allowing the cycling schedule to adapt to changing tube conditions. This resolves the contradiction by enabling power reduction through cycling while maintaining consistent power output despite variations in tube start time.
Solution Approach 2:
The patent applies parameter changes by modifying the time base parameter based on the detected tube start time. When the tube takes longer to start, the time base is extended; when start time is shorter, the time base is reduced. This dynamic parameter adjustment maintains power consistency while optimizing cooking efficiency by preventing unnecessarily long cycle times.
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 approach ensures consistent power levels are maintained across different power settings and tube start times, preventing excessively long cycle times and compensating for slow starting magnetrons during short cook cycles, thereby enhancing cooking efficiency.
Implementation Method 1
a microwave employs a magnetron to generate microwaves which are directed into an oven cavity for cooking purposes
Implementation Method 2
The start time of the tube is derived by measuring current to a magnetron power supply and finding the threshold where the tube conducts
Data Source
AI summary
A microwave oven having a cabinet, a door, a programming interface, a magnetron tube that capable of being dynamically controlled, a controller configured to control the magnetron tube, and a microwave generating system is described. A method of dynamically controlling the magnetron tube in the microwave oven by utilizing a magnetron power supply is also described. By monitoring a current to the magnetron power supply, determining the current to the magnetron power supply at which the magnetron tube conducts, calculating a time base, and adjusting the time base as the power level required is increased, the control produces consistent power when the magnetron tube is cycled at less than a 100% power level and to compensate for a slow start of the magnetron tube during a short cook cycle.