阅读说明：本技术 电弧检测方法、家用电器及计算机可读存储介质 (Arc detection method, household appliance and computer readable storage medium ) 是由 林晖 林世锋 于 2019-09-16 设计创作，主要内容包括：本发明提供一种电弧检测方法、家用电器及计算机可读存储介质,该方法包括获取电流信号,将一个采样周期划分为多个计算周期,并获取电流信号中高频信号层的幅值；计算电流信号在每一个计算周期内高频信号层的幅值的累加值,判断一个采样周期内,多个计算周期对应的累加值中的最大值是否大于预设阈值,如是,确认该采样周期为异常采样周期；判断在预设时间段内,异常采样周期是否满足预设的异常条件,如是,发出电弧故障报警信息。本发明还提供应用上述方法的家用电器以及实现该方法的计算机可读存储介质。本发明能够提高电弧检测的灵敏度以及准确率。(The invention provides an arc detection method, a household appliance and a computer readable storage medium, wherein the method comprises the steps of obtaining a current signal, dividing a sampling period into a plurality of calculation periods, and obtaining the amplitude of a high-frequency signal layer in the current signal; calculating the accumulated value of the amplitude of the high-frequency signal layer of the current signal in each calculation period, judging whether the maximum value of the accumulated values corresponding to a plurality of calculation periods is greater than a preset threshold value in one sampling period, and if so, determining that the sampling period is an abnormal sampling period; and judging whether the abnormal sampling period meets a preset abnormal condition within a preset time period, and if so, sending arc fault alarm information. The invention also provides a household appliance applying the method and a computer readable storage medium for realizing the method. The invention can improve the sensitivity and accuracy of arc detection.)

1. An arc detection method, comprising:

acquiring a current signal, dividing a sampling period into a plurality of calculation periods, and acquiring the amplitude of a high-frequency signal layer in the current signal;

Calculating an accumulated value of the amplitude values of the high-frequency signal layer of the current signal in each calculation period, judging whether the maximum value of the accumulated values corresponding to the calculation periods is larger than a preset threshold value in one sampling period, and if so, determining that the sampling period is an abnormal sampling period;

And judging whether the abnormal sampling period meets a preset abnormal condition within a preset time period, and if so, sending arc fault alarm information.

2. the arc detection method of claim 1, wherein:

Judging whether the abnormal sampling period meets a preset abnormal condition in the preset time period comprises the following steps: and judging whether the number of the abnormal sampling periods in the preset time period is greater than a first preset number threshold value.

3. The arc detection method of claim 1, wherein:

Judging whether the abnormal sampling period meets a preset abnormal condition in the preset time period comprises the following steps: and judging whether the continuous abnormal sampling period which is larger than a second preset number threshold value appears in the preset time period.

4. the arc detection method according to any one of claims 1 to 3, characterized in that:

Acquiring the amplitude of the high-frequency signal layer in the current signal comprises the following steps: and obtaining the amplitudes of at least two high-frequency signal layers of the current signals, wherein the frequencies of the high-frequency signal layers are independent.

5. the arc detection method of claim 4, wherein:

Calculating the accumulated value of the amplitude values of the high-frequency signal layer in one calculation period of the current signal comprises the following steps: calculating the accumulated value of the amplitude corresponding to each high-frequency signal layer in a calculation period of the current signal;

Determining whether a maximum value of the accumulated values corresponding to the plurality of calculation periods within one sampling period is greater than a preset threshold value includes: and judging whether the maximum value of the accumulated values corresponding to a plurality of calculation periods of at least one high-frequency signal layer in one sampling period is larger than a preset threshold value or not.

6. The arc detection method of claim 4, wherein:

confirming that a sampling period is an abnormal sampling period comprises the following steps: in the sampling period, the maximum value of the accumulated values corresponding to the plurality of calculation periods of any one layer of the high-frequency signal layer is greater than the preset threshold value.

7. The arc detection method of claim 4, wherein:

Confirming that a sampling period is an abnormal sampling period comprises the following steps: in the sampling period, the maximum value of the accumulated values corresponding to the calculation periods of at least two high-frequency signal layers is larger than the preset threshold value.

8. The arc detection method according to any one of claims 1 to 3, characterized in that:

Calculating an accumulated value of the amplitudes of the high-frequency signal layer in one calculation cycle includes: and calculating the sum of the absolute values of the amplitudes or the sum of the energy of the amplitudes of the high-frequency signal layers in a calculation period.

9. The arc detection method according to any one of claims 1 to 3, characterized in that:

the preset threshold is a preset multiple of an average value of accumulated values of amplitudes of the high-frequency signal layer in a plurality of continuous calculation periods of the high-frequency signal layer when no arc fault occurs.

10. The arc detection method according to any one of claims 1 to 3, characterized in that:

Acquiring the amplitude of the high-frequency signal layer in the current signal comprises the following steps: and performing wavelet transformation on the current signal, and acquiring the amplitude of the high-frequency signal layer according to the result of the wavelet transformation.

11. Household appliance, characterized in that it comprises a housing in which a circuit board is arranged, said circuit board being provided with a processor and a memory, said memory storing a computer program which, when executed by said processor, carries out the steps of the arc detection method according to any one of claims 1 to 10.

12. A computer-readable storage medium having stored thereon a computer program, characterized in that: the computer program, when being executed by a processor, carries out the steps of the arc detection method according to any one of claims 1 to 10.

Technical Field

The invention relates to the field of electric appliance fault detection, in particular to an electric arc detection method, a household electric appliance for realizing the method and a computer readable storage medium.

Background

Most of existing household appliances use 220 v alternating current, and generally, the household appliances are connected to a socket through a power plug to take electricity from the socket. In the running process of the household appliance, fault electric arcs can be caused due to the conditions of insulation aging or breakage of electric wires, poor contact and the like, the temperature of spark of the fault electric arcs is very high, surrounding combustible materials can be ignited, and fire disasters can be caused. Therefore, current sensors are arranged on the existing household appliances and the safety socket to collect current waveforms of the household appliances, electric arcs are detected according to the current waveforms, and once the electric arc faults are detected, the electric connection between the household appliances and the safety socket is disconnected immediately, so that the power supply of the household appliances is cut off, and the fire is avoided.

The existing arc detection technology generally detects the waveform of a current signal of a household appliance, decomposes a high-frequency signal of the current signal by using a wavelet transform method, and judges whether a fault arc occurs according to the amplitude of the high-frequency signal. Referring to fig. 1, the current signal is decomposed into multiple high frequency signal layers by using DB5 wavelet basis, such as high frequency signal layers d1, d2 and d3, the frequency bands corresponding to each high frequency signal layer are not the same, and do not overlap, such as the frequency of high frequency detail layer d1 is 250KHz to 500KHz, the frequency of high frequency detail layer d2 is 125KHz to 250KHz, and the frequency of high frequency detail layer d3 is 62.5KHz to 125 KHz.

As can be seen from the contact voltage waveforms in fig. 1, the first half of the waveform in fig. 1 is a waveform in which no arc fault occurs, and the second half of the waveform in fig. 1 is a waveform in which an arc fault occurs. As can be seen from fig. 1, the amplitude change is not very significant when the high frequency signal at the time of the arc fault is compared with the high frequency signal at the time of normal operation. Generally, the arc is detected by determining whether the amplitude of the high frequency signal layer exceeds a predetermined amplitude threshold, and if the amplitude of the high frequency signal layer exceeds the amplitude threshold, the arc fault is confirmed.

Because the current signal of the household appliance is interfered when the household appliance normally operates, and some sharp pricks also exist in the waveform of the high-frequency signal layer, in order to reduce misjudgment, the amplitude threshold value is usually set to be higher, or the maximum value of the high-frequency signal layer when the household appliance normally operates is used as the amplitude threshold value. However, in practical application, when an arc fault occurs, the number of high-frequency signals of which the amplitude of the high-frequency signal layer exceeds the amplitude threshold is not large, so that the existing arc detection technology is not sensitive enough, the detection time of the arc fault is long, the time of tripping protection is long, and the use safety of household appliances is affected.

Disclosure of Invention

A first object of the present invention is to provide an arc detection method with a short detection time and high sensitivity.

A second object of the present invention is to provide a household appliance implementing the above-mentioned arc detection method.

It is a third object of the present invention to provide a computer readable storage medium for implementing the above-mentioned arc detection method.

In order to achieve the first object of the present invention, the arc detection method provided by the present invention comprises obtaining a current signal, dividing a sampling period into a plurality of calculation periods, and obtaining the amplitude of a high frequency signal layer in the current signal; calculating the accumulated value of the amplitude of the high-frequency signal layer of the current signal in each calculation period, judging whether the maximum value of the accumulated values corresponding to a plurality of calculation periods is greater than a preset threshold value in one sampling period, and if so, determining that the sampling period is an abnormal sampling period; and judging whether the abnormal sampling period meets a preset abnormal condition within a preset time period, and if so, sending arc fault alarm information.

According to the scheme, whether the arc fault occurs is judged not only by depending on the amplitude of the high-frequency signal layer, but also by accumulating the amplitudes of the high-frequency signals in a calculation period, and calculating the accumulated value as a basis for judging whether the arc fault occurs. Because the amplitude of the high-frequency signal in the current signal continuously fluctuates greatly when the electric arc occurs, the electric arc can be quickly and accurately detected by accumulating the accumulated value of the amplitude of the high-frequency signal layer within a period of time, the electric arc detection is more accurate, and the sensitivity is higher.

One preferable scheme is that the judging whether the abnormal sampling period in the preset time period meets the preset abnormal condition includes: and judging whether the number of the abnormal sampling periods in the preset time period is greater than a first preset number threshold value.

Therefore, if the number of abnormal sampling periods is large in the preset time period, the current arc fault can be confirmed, and the arc fault can be detected more accurately.

Optionally, the determining whether the abnormal sampling period in the preset time period meets the preset abnormal condition includes: and judging whether continuous abnormal sampling periods larger than a second preset number threshold appear in the preset time period.

It can be seen that if a plurality of consecutive sampling periods are abnormal sampling periods within a period of time, it indicates that the current signal has continuous fluctuation, and it can be confirmed that an arc fault has occurred.

Further, obtaining the amplitude of the high-frequency signal layer in the current signal comprises: obtaining the amplitudes of at least two high-frequency signal layers of the current signal, wherein the frequencies of the high-frequency signal layers are independent.

Therefore, the multi-layer high-frequency signal layer is obtained through the wavelet transformation mode, and the amplitude of the multi-layer high-frequency signal layer is calculated, so that whether the arc fault occurs or not can be detected more accurately and rapidly.

Further, the method for calculating the accumulated value of the amplitude values of the high-frequency signal layer in a calculation period of the current signal comprises the following steps: calculating the accumulated value of the amplitude corresponding to each high-frequency signal layer of the current signal in a calculation period; judging whether the maximum value of the accumulated values corresponding to a plurality of calculation periods in one sampling period is larger than a preset threshold value comprises the following steps: and judging whether the maximum value of accumulated values corresponding to a plurality of calculation periods of at least one high-frequency signal layer in one sampling period is larger than a preset threshold value or not.

Therefore, the amplitude accumulated value of each high-frequency signal layer is respectively calculated, the maximum value of the accumulated value is compared with the preset threshold value, namely the multiple high-frequency signal layers are independently calculated, and whether the arc fault occurs or not can be rapidly detected.

Further, the step of determining a sampling period as an abnormal sampling period comprises: in the sampling period, the maximum value of accumulated values corresponding to a plurality of calculation periods of any layer of high-frequency signal layer is greater than a preset threshold value.

therefore, if the maximum value of the accumulated values corresponding to the multiple calculation periods of any one high-frequency signal layer is larger than the preset threshold value, the sampling period can be confirmed to be an abnormal sampling period, the abnormal sampling period can be rapidly determined, and the sensitivity of arc detection is high.

Optionally, the determining that a sampling period is an abnormal sampling period includes: in the sampling period, the maximum value of accumulated values corresponding to a plurality of calculation periods of at least two high-frequency signal layers is larger than a preset threshold value.

Therefore, whether the arc fault occurs or not is confirmed through the accumulated values of more than two high-frequency signal layers, the situation of false detection can be effectively avoided, and the accuracy of arc detection can be improved.

Further, the calculating the accumulated value of the amplitudes of the high-frequency signal layer in one calculation period comprises: and calculating the sum of the absolute values of the amplitudes or the sum of the energy of the amplitudes of the high-frequency signal layers in a calculation period.

therefore, the sum of the absolute values of the amplitudes or the sum of the energy of the amplitudes is used as the accumulated value of the amplitudes, so that the accumulated value is simpler to calculate, the calculation amount is less, and the arc detection time is shorter.

In a further aspect, the preset threshold is a preset multiple of an average value of accumulated values of amplitudes of the high-frequency signal layer in a plurality of consecutive calculation cycles of the high-frequency signal layer when no arc fault occurs.

Therefore, the preset threshold value is set more reasonably by taking the preset multiple of the average value of the accumulated values of the amplitudes of the high-frequency signal layer as the preset threshold value, the preset threshold value is adjusted according to the actual use condition of the household appliance, and the possibility of false detection is reduced.

Further, obtaining the amplitude of the high frequency signal layer in the current signal comprises: and performing wavelet transformation on the current signal, and acquiring the amplitude of the high-frequency signal layer according to the result of the wavelet transformation.

Therefore, the data of the multilayer high-frequency signal layers of the current signal, including the data of the amplitude, can be rapidly acquired by using the wavelet transform, the time required by arc detection is reduced, and the response time of the arc detection is shorter.

In order to achieve the second objective, the household electrical appliance provided by the present invention has a housing, a circuit board is disposed in the housing, a processor and a memory are disposed on the circuit board, the memory stores a computer program, and the computer program realizes the steps of the arc detection method when being executed by the processor.

To achieve the third object, the present invention provides a computer readable storage medium having a computer program stored thereon, the computer program, when being executed by a processor, implementing the steps of the arc detection method.

drawings

Fig. 1 is a current waveform diagram and a waveform diagram of a high frequency signal layer when a home appliance is operated.

FIG. 2 is a schematic circuit diagram of an embodiment of an arc detection method embodying the present invention.

FIG. 3 is a flow chart of an embodiment of the arc detection method of the present invention.

Fig. 4 is a waveform diagram of a current waveform diagram and a waveform diagram of a sum of absolute values of amplitudes of high-frequency signal layers when the household appliance is operated.

FIG. 5 is a waveform diagram of current and amplitude energy sum of high frequency signal layer when the household appliance is in operation.

The invention is further explained with reference to the drawings and the embodiments.

Detailed Description

The electric arc detection method is applied to household appliances such as air conditioners, washing machines, refrigerators and the like, the household appliances are provided with a shell, a circuit board is arranged in the shell, a processor and a memory are arranged on the circuit board, the memory stores a computer program, and the processor executes the computer program to realize the electric arc detection method.

arc detection method embodiment:

The embodiment is applied to the household appliance, judges whether an arc fault occurs or not after the current signal is analyzed by collecting the current signal of the power line of the household appliance, and sends alarm information and disconnects the electric connection between the household appliance and the socket once the arc fault occurs.

Referring to fig. 2, the power cord of the household appliance includes a live wire 18 and a neutral wire 17, and the household appliance is further provided with a switch 10, and when the switch 10 is closed, the household appliance obtains alternating current and supplies power to a plurality of loads, which are power consumers arranged in the household appliance, such as a motor 11, a compressor 12, and the like. In order to collect the current signal on the live wire 18, the household appliance is provided with a current transformer 13, the current transformer 13 collects the current signal flowing through the live wire 18, the collected signal passes through a signal amplifying circuit 14 and then is output to a processor 15, and the received signal is analyzed by the processor 15. Preferably, the signal amplifying circuit 14 and the processor 15 may be disposed on the same circuit board, thereby saving the number of circuit boards for the home appliance and facilitating the miniaturization of the home appliance.

The operation of the present embodiment will be described with reference to fig. 3. First, step S1 is executed, and the processor obtains an amplified current signal, where the obtained current signal is a digital signal. In this embodiment, the processor samples the signal input by the signal amplifying circuit according to a certain frequency, for example, the sampling frequency is 1MHz, and one million sampling values are obtained within 1 s. Assume that a sampling period is set to 10ms, so that 10K samples, which are current values represented in the form of digital signals, can be obtained within one sampling period.

Then, step S2 is performed, and wavelet transform is performed on the sample values obtained in step S1, thereby decomposing multiple layers of high-frequency signal layers. For example, the high frequency signal is decomposed from the current signal using the known DB5 wavelet transform method. Specifically, in this embodiment, three high-frequency signals are decomposed in three layers to obtain three high-frequency signal layers, see fig. 4, the three high-frequency signal layers are respectively high-frequency signal layers d1, d2 and d3, wherein the frequency range of the high-frequency signal layer d1 is (250 KHz-500 KHz), the frequency range of the high-frequency signal layer d2 is (125 KHz-250 KHz), and the frequency range of the high-frequency signal layer d3 is (62.5 KHz-125 KHz).

After wavelet transformation, multiple layers of high-frequency signal layers can be obtained, and the amplitude of each layer of high-frequency signal layer can be obtained.

Next, one sampling period is divided into a plurality of calculation periods, for example, in this embodiment, one sampling period is divided into 20 calculation periods, the time length of each calculation period is 0.5ms, since 10K sampling values are obtained in one sampling period, there are 500 sampling values in each calculation period, and correspondingly, 500 d1 high-frequency signal amplitudes, denoted as Id1(i), are generated in the high-frequency signal layer d1, where i is 1,2, …, and 500.

Correspondingly, for the high-frequency signal layer d2, 500 d2 high-frequency signal amplitudes, denoted as Id2(i), i being 1,2, …, 500, are generated per calculation cycle, and for the high-frequency signal layer d3, 500 d3 high-frequency signal amplitudes, denoted as Id3(i), i being 1,2, …, 500, are generated per calculation cycle.

Then, the accumulated value of the amplitude values of the high-frequency signal layers in each calculation period is calculated. In this embodiment, the accumulated value of the amplitudes of the high-frequency signal layer is the sum of absolute values of a plurality of amplitudes of the high-frequency signal layer in one calculation period, or the sum of amplitude energies of a plurality of high-frequency signals in one calculation period.

taking the high-frequency signal layer d1 as an example, during a calculation period, the sum Sumd1 of the absolute values of the amplitudes of 500 high-frequency signals in the high-frequency signal layer d1 can be calculated by using formula 1, and the sum Sumdd1 of the amplitudes of 500 high-frequency signals can be calculated by using formula 2.

Similarly, the sum Sumd2 of the absolute values of the amplitudes of the high-frequency signal layer d2 and the sum Sumdd2 of the amplitude energies may be calculated using the above-described method, and the sum Sumd3 of the absolute values of the amplitudes of the high-frequency signal layer d3 and the sum Sumdd3 of the amplitude energies may be calculated using the above-described method.

Then, step S3 is executed to find the largest amplitude accumulation value of each high frequency signal layer in a plurality of calculation cycles within one sampling period. For example, in the high-frequency signal layer d1, the maximum value Sumd1max of the sum of absolute values of the amplitudes calculated in 20 calculation periods or the maximum value Sumdd1max of the sum of energy of the amplitudes calculated in 20 calculation periods is found in one sampling period, i.e., 10 ms.

then, step S4 is executed to determine whether the maximum value is greater than the preset threshold value, if so, step S5 is executed, otherwise, step S1 is executed again. In the present embodiment, a preset threshold is set in advance, for example, a preset threshold Sumd1limit of the sum of absolute values of amplitudes is set in advance for the high-frequency signal layer d1, and a preset threshold Sumdd1limit of the sum of energy of amplitudes is set in advance. Step S4 compares the magnitude of the maximum sum of absolute amplitude values Sumd1max with the magnitude of the preset threshold sum 1limit of the sum of absolute amplitude values, and/or compares the magnitude of the maximum sum of amplitude energy sums Sumdd1max with the magnitude of the preset threshold sum 1limit of amplitude energy sums.

If the maximum sum of absolute amplitude values Sumd1max of the plurality of calculation periods is greater than the preset threshold sum 1limit of the sum of absolute amplitude values in a certain sampling period, the determination result in the step S4 is yes, and the step S5 is executed to confirm that the sampling period is an abnormal sampling period. If the maximum value Sumdd1max of the sum of the amplitude energies in the plurality of calculation periods is greater than the preset threshold Sumdd1limit of the sum of the amplitude energies in one sampling period, the judgment result of step S4 is yes, and step S5 is executed. It can be seen that, as long as the maximum value Sumd1max of the sum of absolute values of the amplitudes is greater than the preset threshold value Sumd1limit of the sum of absolute values of the amplitudes, or the maximum value Sumdd1max of the sum of energy of the amplitudes is greater than the preset threshold value Sumdd1limit of the sum of energy of the amplitudes, the determination result of step S4 is yes.

In this embodiment, since there are three high-frequency signal layers, in step S4, it is also necessary to determine the results of the high-frequency signal layer d2 and the high-frequency signal layer d3, for example, for the high-frequency signal layer d2, the magnitude of the preset threshold sum 2limit of the sum of the absolute values of the amplitudes Sumd2max and the sum of the absolute values of the amplitudes of the layer needs to be compared, or the magnitude of the preset threshold sum 2limit of the sum of the amplitudes energy Sumdd2max and the sum of the amplitudes of the energy sums needs to be compared, as long as the maximum sum 2max of the absolute values of the amplitudes is greater than the preset threshold sum 2limit of the sum of the absolute values of the amplitudes, or the maximum sum 2max of the amplitudes of the energy sums is greater than the preset threshold sum 2limit of the amplitudes, the determination result of step S4 is yes.

For the high-frequency signal layer d3, it is necessary to compare the magnitude of the maximum sum of absolute amplitude values Sumd3max and the preset threshold sum 3limit of the sum of absolute amplitude values of the layer, or compare the magnitude of the maximum sum of absolute amplitude values Sumdd2max and the preset threshold sum 3limit of the sum of amplitude values, as long as the maximum sum of absolute amplitude values Sumd3max is greater than the preset threshold sum 3limit of the sum of absolute amplitude values, or the maximum sum of absolute amplitude values Sumdd2max is greater than the preset threshold sum 3limit of the sum of amplitude values, the determination result of step S4 is yes.

as can be seen, in step S4, as long as any one of the three high-frequency signal layers satisfies the following condition: in a sampling period, the maximum value of the sum of the absolute values of the amplitudes of the layer is larger than a preset threshold value of the sum of the absolute values of the amplitudes, or the maximum value of the sum of the energy of the amplitudes is larger than a preset threshold value of the sum of the energy of the amplitudes, and the sampling period is considered as an abnormal sampling period.

Of course, in practical applications, in order to reduce the possibility of false detection, the amplitudes of at least two high-frequency signal layers may be set to satisfy the following conditions: in a sampling period, the maximum value of the sum of the absolute amplitude values of the layer is larger than a preset threshold of the sum of the absolute amplitude values, or the maximum value of the sum of the amplitude energy values is larger than a preset threshold of the sum of the amplitude energy values, and the sampling period is considered as an abnormal sampling period.

Alternatively, the following conditions need to be satisfied for a certain high-frequency signal layer: in a sampling period, the maximum value of the sum of the absolute amplitude values of the layer is greater than the preset threshold value of the sum of the absolute amplitude values, and the maximum value of the sum of the amplitude energy values of the layer is greater than the preset threshold value of the sum of the amplitude energy values, so that the sampling period is considered as an abnormal sampling period.

in this embodiment, the preset threshold for the sum of absolute values of amplitudes of each layer and the preset threshold for the sum of energy of amplitudes of each layer may be preset, or may be calculated according to the amplitudes of the high-frequency signal layer for a plurality of consecutive sampling periods.

For example, taking the preset threshold Sumd1limit of the sum of the absolute values of the amplitudes of the high-frequency signal layer d1 as an example, the calculation can be performed by the following method:

First, the sum of absolute values of amplitudes of the high-frequency signal layer d1 in a plurality of consecutive calculation cycles is obtained, and is denoted as Sumd1(i), where i is 1,2, …, p, where p is the number of consecutive calculation cycles, and preferably, the number of p is greater than or equal to 5.

Then, an average value Advsumd1 of the sum of absolute values of the amplitudes for a plurality of successive calculation cycles is calculated, for example, using equation 3.

Finally, a preset multiple of the average value Advsumd1 is taken as a preset threshold Sumd1limit of the sum of absolute values of the amplitudes, that is, Sumd1limit ═ η × Advsumd1, preferably, the preset multiple η is greater than or equal to 1.2, and the embodiment may be 1.3.

Similarly, the sum of the amplitude energies of the high-frequency signal layer d1 and the preset threshold Sumdd1limit are calculated in the same way, for example, the sum of the amplitude energies of the high-frequency signal layer d1 in a plurality of consecutive calculation cycles is calculated, which is denoted as Sumdd1(i), where i is 1,2, …, p.

Then, an average value Advsumdd1 of the sum of the amplitude energies for a plurality of successive calculation cycles is calculated, for example, using equation 4.

Finally, the preset multiple of the average value Advsumdd1 is used as the preset threshold Sumdd1limit of the amplitude energy sum, i.e., the sum Sumdd1limit is η × Advsumd 1.

Correspondingly, the preset threshold of the sum of the absolute values of the amplitudes of the high-frequency signal layers d2 and d3 and the preset threshold of the sum of the energy of the amplitudes are also calculated by using the same method, and are not described again.

After confirming that the sampling period is the abnormal sampling period, step S6 is executed to calculate the number of abnormal sampling periods within the preset time period. For example, the preset time period may be set to 0.5S, so that 50 sampling cycles are included in one preset time period, and step S6 counts how many sampling cycles are determined as abnormal sampling cycles in the 50 sampling cycles.

Then, step S7 is executed to determine whether the number of abnormal sampling cycles satisfies a preset abnormal condition within a preset time period. In this embodiment, the abnormal condition is preset, for example, the abnormal condition is whether the number of abnormal sampling cycles is greater than a preset number, for example, greater than a first preset number threshold value within a preset time period, and the determination result of step S7 is yes, step S8 is executed, an arc fault warning message is issued, and the power supply of the household appliance is disconnected. Preferably, the first preset number threshold may be 5 or 8.

the alarm information of sending the arc fault can be sent out through the display screen of the household appliance or the LED indicating lamp or the loudspeaker, and if the household appliance is communicated with the terminal equipment through the network, the alarm information can be sent to the terminal equipment. Switching off the power supply of the household appliance may control a switching action of the household appliance, e.g. from a closed state to an open state.

If the judgment result of the step S7 is NO, it indicates that the arc fault does not occur in the household appliance, and the process returns to the step S1.

The other scheme is that the preset abnormal condition is not the total number of abnormal sampling periods in the preset time period, but the number of the abnormal sampling periods which continuously appear in the preset time period, that is, if a plurality of continuous sampling periods in the preset time period are the abnormal sampling periods, the occurrence of the arc fault can also be determined. Therefore, the preset abnormal condition may be that continuous abnormal sampling cycles larger than a second preset number threshold occur within a preset time period, and preferably, the second preset number threshold is smaller than the first preset number threshold, for example, the second preset number threshold is 3.

Referring to fig. 4 and 5, compared with the case where no arc fault occurs, after the arc fault occurs, the sum of absolute values of amplitudes or the sum of energy of amplitudes of the high-frequency signal layer within a calculation period changes significantly, and the change range is large, so that the method of the present invention can rapidly detect the arc fault, is very sensitive to the detection of the arc fault, has short response time for the detection of the arc fault, can cut off the power supply of the household appliance in a short time, avoids the continuous arc phenomenon, and effectively avoids the occurrence of fire and other situations. In fig. 4, "d 1 calculation period amplitude sum waveform" refers to a waveform diagram of the sum of absolute values of amplitudes of a plurality of calculation periods of the high-frequency signal layer d1, and "d 1 calculation period energy sum waveform" refers to a waveform diagram of the sum of amplitude energies of a plurality of calculation periods of the high-frequency signal layer d1 in fig. 5.

In addition, the sum of the absolute values of the amplitudes or the sum of the energy of the amplitudes changes obviously before and after the occurrence of the arc, so that the arc detection accuracy of the embodiment is higher than that of the existing detection method, and the probability of false detection is greatly reduced.

household appliance embodiment:

The household appliance of the embodiment has a housing, a circuit board is arranged in the housing, a processor and a memory are arranged on the circuit board, a computer program which can run on the processor is stored in the memory, and the processor executes the computer program to realize the steps of the arc detection method.

For example, a computer program may be partitioned into one or more modules that are stored in a memory and executed by a processor to implement the modules of the present invention. One or more of the modules may be a series of computer program instruction segments capable of performing certain functions, which are used to describe the execution of the computer program in the terminal device.

The Processor may be a Central Processing Unit (CPU), or may be other general-purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, a discrete Gate or transistor logic device, a discrete hardware component, or the like. The general purpose processor may be a microprocessor or the processor may be any conventional processor or the like, the processor being the control center of the appliance and connected to the various parts of the overall appliance by various interfaces and lines.

The memory may be used to store computer programs and/or modules, and the processor may implement various functions of the appliance by operating or executing the computer programs and/or modules stored in the memory and calling data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, a phonebook, etc.) created according to the use of the appliance, and the like. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.

A computer-readable storage medium:

The computer program stored in the memory of the home appliance may be stored in a computer-readable storage medium if it is implemented in the form of a software functional unit and sold or used as a separate product. Based on such understanding, all or part of the flow of the method according to the above embodiments may be implemented by a computer program, which may be stored in a computer readable storage medium and used by a processor to implement the steps of the arc detection method.

Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer readable medium may include: any entity or device capable of carrying computer program code, recording medium, U.S. disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution media, and the like. It should be noted that the computer readable medium may contain other components which may be suitably increased or decreased as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, in accordance with legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunications signals.

Finally, it is emphasized that the present invention is not limited to the above-described embodiments, such as the change of the preset abnormal condition or the change of the calculation formula for calculating the preset threshold, and these changes should be included in the protection scope of the claims of the present invention.