Ion flame detection circuit and method

Abstract

The invention discloses an ion flame detection circuit and a method. The ion flame detection circuit comprises a single-chip microcomputer, a DC-DC unit, a positive direct-current analog switch, a negative direct-current analog switch, a positive direct-current sampling unit, a negative direct-current sampling unit, an optocoupler circuit U1, a detection circuit, and a CPU, wherein the CPU generates a PWM pulse width modulation signal, and the DC-DC unit changes the voltage and current output of the PWM pulse width through the positive direct-current analog switch and the negative direct-current analog switch; and the single-chip microcomputer measures flame equivalent resistance through resistance voltage division and indirectly measures ion current. The direct-current signal ion electric energy is adopted to eliminate the shunting effect of the stray capacitance, especially the influence of the stray capacitance of a burner on the sensitivity.

Description

technical field [0001] The invention relates to the technical field of gas stove ignition circuits, in particular to an ion flame detection circuit and method. Background technique [0002] Gas cookers use flame ion detection for flameout protection, and the contact area between the electrodes and the flame is related to the sensitivity of flame detection. Related studies have shown that the greater the contact area between the positive electrode and the flame, the higher the sensitivity of flame detection; and when the contact area reaches a certain value, the sensitivity of flame detection will no longer increase. Similarly, the larger the contact area between the negative electrode and the flame sensitivity is, the higher the flame detection sensitivity will be. When the contact area reaches a certain value, the flame detection sensitivity will no longer increase. At the same time, when the area of ​​the negative electrode is much larger than the area of ​​the positive e...

AI Technical Summary

Problems solved by technology

Due to technological reasons, the burner mostly adopts a detachable structure, and the materials of the burner are also diversified, which leads to the problem of poor grounding of the burner after a period of use

This results in a double-electrode flame induction, but due to the reduced contact area of ​​the negative electrode, the flame detection sensitivity is reduced, especially when the range of load adjustment of the cooker is relatively wide. When the flame is small, the flame contact area is smaller, which leads to the flame detection sensitivity. lower

Therefore, in view of the existing problem of unreliable flame detection, it is very difficult to solve structurally due to technical reasons, and a new solution is urgently needed

Images