A method for realizing a leakage current sensor with dual trip functions

Abstract

The present invention discloses a method for realizing a leakage current sensor with dual Tirp functions, which is used to meet different safety regulations for residual current, and includes step S1: a single fluxgate acquisition circuit of the current sensor acquires the original mixed wave signal containing currents of various frequency bands and pre-processes the original mixed wave signal through a processor to obtain DC component energy, AC component energy and multi-frequency component energy. The present invention discloses a method for realizing a leakage current sensor with dual Tirp functions, which uses a single fluxgate acquisition circuit, separates the signal into A-type and rectified wave after FFT Fourier transformation, and performs integration delay judgment output according to the two safety regulations of GB16917.1 and IEC62955, respectively. This processing method has the advantages of easy use, low cost and stable structure.

Description

Technical Field

[0001] The invention belongs to the technical field of leakage current sensors, and in particular relates to a method for realizing a leakage current sensor with a double trip function. Background Art

[0002] In the charging system of the car charging pile, the residual current protection function is divided into two categories, which need to meet the safety regulations GB16917.1 (Type A residual current protector) and IEC62955 (6mA DC and rectifier wave residual current protector). Usually, they are two physically completely independent protectors. Type A adopts the principle of electromagnetic induction to couple the residual current to the acquisition circuit through the mutual inductance coil and the induction coil; 6mA DC uses a fluxgate sensor to collect signals, so two independent hardware acquisition systems with different principles are required. The production cost is relatively high, and safety certification is required separately. Many users have proposed to merge the two independent systems into one sensor to reduce costs. Therefore, further improvements are made to the above problems. Summary of the invention

[0003] The main purpose of the present invention is to provide a method for realizing a leakage current sensor with a dual trip function, which uses a single fluxgate acquisition circuit, separates the signal into type A and rectified wave after FFT Fourier transform, and performs integration delay judgment output in accordance with the two safety regulations of GB16917.1 and IEC62955. This processing method has the advantages of easy use, low cost and stable structure.

[0004] To achieve the above objectives, the present invention provides a method for implementing a leakage current sensor with a dual trip function, which is used to meet different safety regulations of residual current, and comprises the following steps:

[0005] Step S1: Single fluxgate acquisition circuit of current sensor (corresponding to Figure 1 ADC acquisition) collects the original mixed wave signal containing the current of each frequency band and pre-processes the original mixed wave signal through the processor (FFT Fourier transform, separation of DC and each spectrum signal) to obtain DC component energy, AC component energy and multi-frequency component energy;

[0006] Step S2: The obtained DC component energy, AC component energy and multi-frequency component energy are used as input energy (preferably 50-60HZ) for ratio calculation to determine the ratio of the sine wave and the non-sinusoidal wave. When the DC component energy is (close to) zero, so that the input energy is a sine wave and reaches the trigger value of the first safety regulation, the trigger data is transmitted to the first channel of the processor, so that the processor determines again whether the trigger data after the first processing (including integral delay, anti-shake, etc.) meets the trigger value of the first safety regulation. If it meets the trigger value, the trigger data is output from the processor, otherwise it is not output;

[0007] Step S3: The obtained DC component energy, AC component energy and multi-frequency component energy are used as input energy (preferably 50-60HZ) for ratio calculation to determine the ratio of the sine wave and the non-sinusoidal wave. When the AC component energy is (close to) zero, so that the input energy is a rectified wave and reaches the trigger value of the second safety regulation, the trigger data is transmitted to the second channel of the processor, so that the processor determines again whether the trigger data after the second processing (including integral delay, anti-shake, etc.) meets the trigger value of the second safety regulation. If it meets the trigger value, the trigger data is output from the processor, otherwise it is not output;

[0008] Step S4: The obtained DC component energy, AC component energy and multi-frequency component energy are used as input energy (preferably 50-60HZ) for ratio calculation to determine the ratio of sinusoidal waves and non-sinusoidal waves. When the input energy is not a pure DC component energy and AC component energy, the input energy is made into noise (other waves, AC+DC, pulsating or mixed waveforms) and is judged by total energy. The trigger data is transmitted to the first channel of the processor so that the processor determines whether the trigger data reaches or exceeds the trigger value for noise in the first safety regulation. If it meets the trigger value, the trigger data is output from the processor, otherwise it is not output.

[0009] As a further preferred technical solution of the above technical solution, the preprocessing includes FFT Fourier transform and separation of AC and DC and each spectrum signal.

[0010] As a further preferred technical solution of the above technical solution, in step S4, the interference is judged by total energy, and after integration delay, if the total energy reaches or exceeds the pulsating wave and superimposed wave threshold and delay time specified in the first safety regulation, the trigger data is output from the first channel of the processor.

[0011] As a further preferred technical solution of the above technical solution, the first processing and the second processing both include integral delay processing and anti-shake processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1It is a schematic diagram of a method for realizing a leakage current sensor with a dual trip function according to the present invention. DETAILED DESCRIPTION

[0013] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0014] In the preferred embodiments of the present invention, those skilled in the art should note that the vehicle charging piles and safety regulations involved in the present invention may be regarded as prior art.

[0015] Preferred embodiments.

[0016] The present invention discloses a method for realizing a leakage current sensor with a dual trip function, which is used to meet different safety regulations of residual current, and comprises the following steps:

[0017] Step S1: Single fluxgate acquisition circuit of current sensor (corresponding to Figure 1 ADC acquisition) collects the original mixed wave signal containing the current of each frequency band and pre-processes the original mixed wave signal through the processor (FFT Fourier transform, separation of DC and each spectrum signal) to obtain DC component energy, AC component energy and multi-frequency component energy;

[0018] Step S2: The obtained DC component energy, AC component energy and multi-frequency component energy are used as input energy (preferably 50-60HZ) for ratio calculation to determine the ratio of the sine wave and the non-sinusoidal wave. When the DC component energy is (close to) zero, so that the input energy is a sine wave and reaches the trigger value of the first safety regulation, the trigger data is transmitted to the first channel of the processor, so that the processor determines again whether the trigger data after the first processing (including integral delay, anti-shake, etc.) meets the trigger value of the first safety regulation. If it meets the trigger value, the trigger data is output from the processor, otherwise it is not output;

[0019] Step S3: The obtained DC component energy, AC component energy and multi-frequency component energy are used as input energy (preferably 50-60HZ) for ratio calculation to determine the ratio of the sine wave and the non-sinusoidal wave. When the AC component energy is (close to) zero, so that the input energy is a rectified wave and reaches the trigger value of the second safety regulation, the trigger data is transmitted to the second channel of the processor, so that the processor determines again whether the trigger data after the second processing (including integral delay, anti-shake, etc.) meets the trigger value of the second safety regulation. If it meets the trigger value, the trigger data is output from the processor, otherwise it is not output;

[0020] Step S4: The obtained DC component energy, AC component energy and multi-frequency component energy are used as input energy (preferably 50-60HZ) for ratio calculation to determine the ratio of sinusoidal waves and non-sinusoidal waves. When the input energy is not a pure DC component energy and AC component energy, the input energy is made into noise (other waves, AC+DC, pulsating or mixed waveforms) and is judged by total energy. The trigger data is transmitted to the first channel of the processor so that the processor determines whether the trigger data reaches or exceeds the trigger value for noise in the first safety regulation. If it meets the trigger value, the trigger data is output from the processor, otherwise it is not output.

[0021] Specifically, the preprocessing includes FFT Fourier transform and separation of AC and DC signals from each spectrum signal.

[0022] More specifically, in step S4, the clutter is judged by total energy, and after integration delay, if the total energy reaches or exceeds the pulse wave and superposition wave threshold and delay time specified in the first safety regulation, trigger data is output from the first channel of the processor.

[0023] Furthermore, the first processing and the second processing both include integral delay processing and anti-shake processing.

[0024] The principle of the present invention is: the dual trip "A+6" is two completely independent operations, two logic units (A+6) that operate and trigger output on their respective signals respectively. The reason for designing dual operations is that they need to process different types of signals and complete independent judgments and outputs (A channel processes various judgments of safety regulations GB16917.1, and 6 channels process various judgments of safety regulations IEC62955). Logically, they are two independent devices, but they are actually the same device at the physical layer. The implementation process is not completely independent, the signal source is the same, and after feature extraction and signal separation, the signals of three channels are separated (two of which are merged into one), and then calculated and judged by two completely independent processing units;

[0025] Implementation algorithm description:

[0026] (1) First, the original mixed wave signal containing currents in various frequency bands is collected from the hardware residual current sensor;

[0027] (2) Perform FFT Fourier transform on the original mixed wave signal to obtain the energy value of each frequency component (including DC component energy, AC energy component and multi-frequency energy component, separating 3 channels);

[0028] (3) Calculate the ratio of the energy of the 50~60HZ frequency component to the DC component. When the DC component is close to 0 and the energy of 50~60hz reaches the trigger value specified in GB16917.1 (threshold 1), the data is sent to Trip1 (the first channel) for integration delay, anti-shake and other processing. Then, it is determined whether the current threshold required by the GB16917.1 safety regulations is met. If it is met, the trigger information is output from Trip1.

[0029] (4) The data whose AC component energy is close to 0 and DC energy meets the IEC62955 trigger value (threshold 3) is sent to Trip2 (the second channel) for integration delay, anti-shake and other processing. Then, the trigger judgment and output are performed again according to the trigger time and trigger current requirements of IEC62955.

[0030] (5) Pulsation and mixed wave judgment: the elimination method is adopted. Except for the two types of waveforms (3) and (4), the rest are pulsation or mixed waveforms. These chaotic waveforms can be judged by total energy. After integration delay, when the energy value reaches or exceeds the pulsation wave and superposition wave threshold and delay time specified in GB16917.1, the trigger information is output from Trip1 (merged into the first channel).

[0031] At this point, the two-way Trip trigger output requirement has been completed, that is, the (A+6) two channels meet the trigger output of two safety regulations respectively.

[0032] It is worth mentioning that the technical features such as car charging piles and safety regulations involved in the patent application of this invention should be regarded as prior art. The specific structure, working principle and possible control method and spatial layout method of these technical features can be selected according to the conventional methods in the field, and should not be regarded as the inventive point of the patent of this invention. The patent of this invention will not be further elaborated.

[0033] For those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for implementing a leakage current sensor with dual trip function, used to meet different safety regulations of residual current, characterized in that: The following steps are involved: Step S1: a single fluxgate acquisition circuit of the current sensor acquires the original mixed wave signal containing the current of each frequency band and pre-processes the original mixed wave signal through a processor to obtain DC component energy, AC component energy and multi-frequency component energy; Step S2: The obtained DC component energy, AC component energy and multi-frequency component energy are used as input energy for ratio calculation to determine the ratio of the sine wave and the non-sinusoidal wave. When the DC component energy is zero, so that the input energy is a sine wave and reaches the trigger value of the first safety regulation, the trigger data is transmitted to the first channel of the processor, so that the processor determines again whether the first processed trigger data meets the trigger value of the first safety regulation. If it meets the trigger value, the trigger data is output from the processor, otherwise it is not output; Step S3: The DC component energy, AC component energy and multi-frequency component energy are obtained as input energy for ratio calculation to determine the ratio of the sine wave and the non-sinusoidal wave. When the AC component energy is zero, so that the input energy is a rectified wave and reaches the trigger value of the second safety regulation, the trigger data is transmitted to the second channel of the processor, so that the processor determines again whether the second processed trigger data meets the trigger value of the second safety regulation. If it meets the trigger value, the trigger data is output from the processor, otherwise it is not output; Step S4: The DC component energy, AC component energy and multi-frequency component energy are obtained as input energy for ratio calculation to determine the ratio of the sine wave and the non-sinusoidal wave. When the input energy is not a pure DC component energy and AC component energy, the input energy is made to be clutter and is judged by the total energy. The trigger data is transmitted to the first channel of the processor so that the processor determines whether the trigger data reaches or exceeds the trigger value for clutter in the first safety regulation. If it is satisfied, the trigger data is output from the processor, otherwise it is not output; In step S4, the clutter is judged by the total energy, and after the integration delay, if the total energy reaches or exceeds the pulse wave and superposition wave threshold and delay time specified in the first safety regulation, the trigger data is output from the first channel of the processor.

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