Dual PWM Control for Electric Heating Appliance Temperature Precision
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Solution Overview
Problem
Conventional electric heating appliances often experience temperature control failures such as dry heating or slow heating speeds, leading to a poor user experience.
Innovation Solution
A control method and device for an electric heating appliance that includes a first switch module, a second switch module, and a load, where a target PWM signal is determined by combining a first PWM signal and a second PWM signal. The first PWM signal ensures reliable on/off switching of the first switch module, while the second PWM signal is based on the target operating parameter of the load, ensuring precise control of the heating appliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single PWM signal is used to control the electric heating appliance, then the control circuit is simple, but temperature control precision deteriorates leading to dry heating or slow heating speeds
Solution Approach 1:
The control circuit is segmented into two independent PWM signal paths: a first PWM signal controls the first switch module for basic on/off switching, while a second PWM signal controls the second switch module for precise power adjustment. This segmentation allows each module to operate independently with optimized control parameters, resolving the contradiction between circuit simplicity and control precision.
Solution Approach 2:
The invention transitions from single-dimension PWM control to two-dimension PWM control by introducing dual PWM signals with different frequencies and duty cycles. The first PWM signal operates at a higher frequency for reliable switching, while the second PWM signal operates at a lower frequency for precise power modulation, adding a new dimension of control capability.
2Device complexity
If a single PWM signal is used to control the electric heating appliance, then the control signal generation is simple, but heating speed deteriorates becoming slow
Solution Approach 1:
The heating control process is segmented into two parallel signal generation paths that independently control different switch modules. The first PWM signal path ensures rapid switching response for quick heating initiation, while the second PWM signal path provides fine-grained power adjustment for optimized heating rate, collectively achieving fast heating speed without excessive complexity.
Solution Approach 2:
The dual PWM signal system ensures continuous and optimized heating action by maintaining both switch modules in active control. The first switch module provides continuous high-frequency switching for stable power delivery, while the second switch module continuously adjusts power levels based on temperature feedback, ensuring uninterrupted and efficient heating throughout the process.
3Device complexity
If a single PWM signal is used to control the electric heating appliance, then the control system is simple, but temperature control reliability deteriorates causing dry heating
Solution Approach 1:
The control system is divided into two independent control channels with separate PWM signal generation and switch modules. This segmentation provides functional redundancy and independent control paths, where the first channel ensures reliable switch activation while the second channel provides precise power management, together eliminating dry heating issues without requiring a completely complex control architecture.
Solution Approach 2:
The temperature sensor provides continuous feedback to the control unit, which independently adjusts both PWM signals based on the detected temperature. This dual-feedback control mechanism ensures that neither switch module causes overheating or dry heating, as the control unit can modulate both signals to maintain safe operating temperatures, significantly improving temperature control reliability.
Data Source
AI summary
A control method for an electric heating appliance having a first switch module, a second switch module, and a load, a control terminal of the first switch module being accessing a target pulse width modulation (PWM) signal, an output terminal of the first switch module being connected to a control terminal of the second switch module, an input terminal of the second switch module accessing a power supply voltage, an output terminal of the second switch module being connected to the load, and an output signal of the first switch module controlling the second switch module to be in an on state or an off state, includes: determining a first PWM signal, the first PWM signal being a signal loaded onto the control terminal of the first switch module in a state in which the first switch module operates independently, so as to drive the first switch module.