Electricity meter and null line falling detection circuit thereof
A detection circuit and detection resistance technology, applied in the field of electric meters, can solve the problems of narrow voltage range, low reliability, adjustment of comparator judgment threshold, etc., and achieve the effect of large voltage detection range and high detection reliability.
Pending Publication Date: 2022-01-21
SHENZHEN KAIFA TECH (CHENGDU) CO LTD
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Problems solved by technology
At present, the existing detection method uses a comparator to judge the output voltage of the rectifier circuit before and after the neutral line is dropped. The judgment threshold of the comparator cannot be dynamically adjusted according to the input voltage, resulting in a narrow detection voltage range, so the detection reliability is not high.
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[0039] Although the present application may readily take the form of embodiments, only some of them are shown in the drawings and will be described in detail in this specification, and it is to be understood that this specification should be considered as the It is an exemplary illustration of the principles of the application and is not intended to limit the application to what is described herein.
[0040] Therefore, a feature indicated in this specification will be used to describe one of the features of an embodiment of the application, rather than implying that every embodiment of the application must have the described feature. Furthermore, it should be noted that this specification describes a number of features. Although certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly described. Thus, the illustrated combinations are not intended to be limiting unless otherwise stated.
[004...
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The invention provides an electricity meter and a null line falling detection circuit thereof. The null line falling detection circuit comprises a rectification circuit, a voltage division circuit and a detection circuit. The input end of the rectification circuit is connected with three-phase alternating current; the voltage division circuit comprises a first voltage division circuit and a second voltage division circuit; the first voltage division circuit is connected between a phase line and a zero line of alternating current; the second voltage division circuit is connected between the output end of the rectifying circuit and a ground wire, and the ground wire is electrically connected with the zero line; the detection circuit is connected with the output end of the rectification circuit; under the condition that the null line is disconnected, the first voltage division circuit and the second voltage division circuit are connected in series between the phase line of the alternating current and the output end of the rectification circuit; the detection circuit is used for detecting the voltage of the output end of the rectification circuit so as to determine the connection state of the zero line according to the voltage of the output end of the rectification circuit. The null line falling detection circuit of the electricity meter has a wide voltage detection range, is not influenced by voltage fluctuation of a power grid, and has good detection reliability.
Description
technical field [0001] The present application relates to the field of electric meter technology, in particular to an electric meter and a zero line detection circuit thereof. Background technique [0002] If the zero line of the electric energy meter falls off or is cut off by someone who steals electricity, it will cause inaccurate measurement and may also cause potential safety hazards. Therefore, the electric energy meter needs the neutral line detection function to accurately judge whether the neutral line is dropped. At present, the existing detection method uses a comparator to judge the output voltage of the rectifier circuit before and after the neutral line is dropped. The judgment threshold of the comparator cannot be dynamically adjusted according to the input voltage, resulting in a narrow detection voltage range, so the detection reliability is not high. [0003] The above information disclosed in this Background section is only for enhancement of understandin...
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Login to View More IPC IPC(8): G01R11/02G01R11/00G01R31/68
CPCG01R11/02G01R11/00G01R31/68
Inventor 周星彭伟
Owner SHENZHEN KAIFA TECH (CHENGDU) CO LTD