Arc fault protection device for electric equipment and control system for electric equipment

Abstract

The present application provides an arc fault protection device for electrical equipment and an electrical equipment control system. The device comprises: a circuit breaker disposed on the power supply line of the electrical equipment; a current detection circuit for detecting the operating current of the electrical equipment; and an arc detection microprocessor having an input connected to the output of the current detection circuit, wherein the output of the arc fault detection microprocessor is connected to a control terminal of the circuit breaker. The device automatically samples the operating current of the electrical equipment via the sampling circuit and sends the sampled current to the arc fault detection microprocessor. The arc fault detection microprocessor determines the presence of an arc fault based on the sampled current. When it is determined that an arc fault has occurred in the electrical equipment, the circuit breaker is controlled to disconnect, thereby powering off the electrical equipment for protection. Thus, when an arc fault occurs in the electrical equipment, the device can be promptly detected and the electrical equipment can be powered off for protection.

Description

Technical Field

[0001] The present invention relates to the technical field of equipment operating condition detection and protection, and in particular to an arc fault protection device for electrical equipment and an electrical equipment control system. Background Art

[0002] With the improvement of living standards, electrical appliances such as air conditioners and refrigerators have gradually entered thousands of households. These appliances have complex internal circuits. Due to aging circuits or substandard internal components, there may be poor electrical connections or internal circuits with aged insulation, which may cause arc faults. Common causes of arc faults are as follows:

[0003] 1. Sharp objects pierce the power cord and squeeze it, causing the insulation layer to be damaged;

[0004] 2. There is a cold solder joint, looseness or oxidation between the neutral wire and the wire joint of the connecting line, resulting in excessive contact resistance and high heat.

[0005] 3. Failure to use correct protective devices, such as circuit breakers.

[0006] 4. The aging of the wire insulation causes the insulation layer to be broken down.

[0007] A commonly used method to prevent arc fires is to protect electrical equipment by installing an air switch (such as a circuit breaker). When the power supply data of the electrical equipment is abnormal, the air switch is controlled to disconnect. Since the above method protects the electrical equipment by detecting the power supply current of the electrical equipment, when a fault current occurs in a device in the electrical equipment, the equipment cannot be protected immediately. Only when the fault current is reflected in the power supply current of the electrical equipment and the power supply current meets the set circuit-breaking conditions can the equipment be powered off for protection. If the power supply current does not meet the circuit-breaking conditions, the circuit breaker cannot provide circuit-breaking protection for the electrical equipment. Therefore, the traditional technical solution has poor reliability and cannot guarantee timely power-off protection of the equipment when a fault arc occurs in the electrical equipment. Summary of the Invention

[0008] In view of this, an embodiment of the present invention provides an arc fault protection device for electrical equipment, so as to timely detect when an arc fault occurs in the electrical equipment and perform power-off protection on the electrical equipment.

[0009] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0010] An arc fault protection device for electrical equipment, comprising:

[0011] Circuit breaker protector installed on the power supply line of electrical equipment;

[0012] A current detection circuit for detecting the operating current of an electrical device;

[0013] An arc detection microprocessor has an input end connected to the output end of the current detection circuit, and an output end of the arc fault detection microprocessor is connected to the control end of the circuit breaker.

[0014] Preferably, the arc fault protection device for electrical equipment may further include:

[0015] A signal modulation circuit and an analog-to-digital conversion circuit are provided between the current detection circuit and the arc detection microprocessor.

[0016] Preferably, the above-mentioned arc fault protection device for electrical equipment may further include:

[0017] The test circuit is used to output a simulated fault arc current signal to the arc detection microprocessor.

[0018] Preferably, the above-mentioned arc fault protection device for electrical equipment may further include:

[0019] A circuit breaker drive circuit is provided between the output terminal of the arc fault detection microprocessor and the control terminal of the circuit breaker.

[0020] Preferably, in the above-mentioned arc fault protection device for electrical equipment, the circuit breaker is an electromagnetic holding relay, the circuit breaker drive circuit is an electromagnetic holding relay drive circuit, and the electromagnetic holding relay drive circuit is used to drive the electromagnetic holding relay to trip according to the trigger signal output by the arc fault detection microprocessor.

[0021] Preferably, the above-mentioned arc fault protection device for electrical equipment may further include:

[0022] A leakage detection circuit, an overcurrent detection circuit, an overvoltage detection circuit, an undervoltage detection circuit and / or a short circuit detection circuit connected to the arc detection microprocessor for detecting electrical equipment.

[0023] Preferably, the above-mentioned arc fault protection device for electrical equipment may further include:

[0024] a wireless signal transmitter connected to the arc detection microprocessor;

[0025] A wireless signal receiver connected to the circuit breaker drive circuit, the wireless signal receiver is used to obtain the control signal output by the wireless signal transmitter for controlling the working state of the circuit breaker through a wireless network.

[0026] Preferably, in the above-mentioned arc fault protection device for electric equipment, the wireless signal transmitter is a wireless signal transmitter in a wireless communication module of the electric equipment.

[0027] Preferably, in the above-mentioned arc fault protection device for electrical equipment, there are multiple current detection circuits, and each current detection circuit corresponds to detecting the operating current of a preset functional module in the electrical equipment.

[0028] Preferably, the arc fault protection device for electrical equipment further comprises:

[0029] The network server is used to obtain a fault signal generated when the arc detection microprocessor detects an arc fault in an electrical device, and output an equipment fault alarm signal to a user terminal according to a preset address.

[0030] An electric equipment control system, applied to electric equipment, comprises:

[0031] An arc fault protection device for electrical equipment as described in any one of the above.

[0032] Preferably, the above-mentioned electrical equipment control system is applied to air-conditioning equipment.

[0033] Based on the above technical solution, the arc fault protection device and the control system for electric equipment provided in the embodiments of the present invention automatically sample the working current of the electric equipment through the sampling circuit, and send the sampled current to the arc fault detection microprocessor. The arc fault detection microprocessor makes a fault arc judgment based on the sampled current. When it is determined that a fault arc occurs in the electric equipment, the circuit breaker is controlled to disconnect to cut off the power supply to the electric equipment, so that when a fault arc occurs in the electric equipment, it can be discovered in time and the electric equipment can be protected by power off. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0035] Figure 1 This is a schematic structural diagram of an arc fault protection device for electrical equipment disclosed in an embodiment of the present application;

[0036] Figure 2 This is a structural schematic diagram of an arc fault protection device for electrical equipment disclosed in another embodiment of the present application;

[0037] Figure 3 This is a structural diagram of an arc fault protection device for electrical equipment disclosed in another embodiment of the present application;

[0038] Figure 4 This is a structural diagram of an arc fault protection device for electrical equipment disclosed in yet another embodiment of the present application;

[0039] Figure 5 This is a schematic diagram of the packaging structure of an arc fault protection device for electrical equipment disclosed in an embodiment of the present application;

[0040] Figure 6 This is a schematic diagram of the packaging structure of an arc fault protection device for electrical equipment disclosed in another embodiment of the present application;

[0041] Figure 7 This is a schematic diagram of the packaging structure of an arc fault protection device for electrical equipment disclosed in another embodiment of the present application;

[0042] Figure 8 This is a schematic diagram of the packaging structure of an arc fault protection device for electrical equipment disclosed in yet another embodiment of the present application;

[0043] Figure 9 This is a schematic diagram of the specific workflow of an arc fault detection microprocessor disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] In view of the problem of poor reliability of the scheme for protecting electrical equipment by circuit breakers in the prior art, this application discloses an arc fault protection device for electrical equipment, see Figure 1 , the apparatus may include:

[0046] A circuit breaker protector 10 is provided on the power supply line of the electrical equipment. The circuit breaker protector 10 is used to cut off the power supply to the electrical equipment when the power supply current of the electrical equipment exceeds the protection value configured by the circuit breaker protector 10. When a trigger signal indicating that a fault arc has occurred in the electrical equipment is output by the arc detection microprocessor 30, the circuit breaker protector 10 also cuts off the power supply to the electrical equipment;

[0047] A current detection circuit 20 for detecting the operating current of the electrical device, wherein the current detection circuit 20 is used to sample the operating current of the electrical device and send the sampled current to the arc detection microprocessor 30, wherein the operating current may refer to the current on the power supply line of the electrical device or the operating current of a functional module within the electrical device;

[0048] An arc detection microprocessor 30 having an input end connected to the output end of the current detection circuit 20, and an output end of the arc fault detection microprocessor 30 connected to the control end of the circuit breaker 10. The arc fault detection microprocessor 30 is used to perform fault judgment on the electrical equipment based on the sampled current output by the current detection circuit 20, to judge whether a fault arc occurs in the electrical equipment, and if so, to output a control signal for triggering the circuit breaker 10 to disconnect.

[0049] When the electrical equipment is in working state, the working current of the electrical equipment is automatically sampled by the sampling circuit 20, and the sampled current is sent to the arc fault detection microprocessor 30. The arc fault detection microprocessor 30 makes a fault arc judgment based on the sampled current. When it is determined that a fault arc occurs in the electrical equipment, the circuit breaker 10 is controlled to disconnect to cut off the power supply to the electrical equipment, so that when a fault arc occurs in the electrical equipment, it can be discovered in time and the electrical equipment can be cut off to protect it.

[0050] In the above scheme disclosed in the embodiment of the present application, the arc fault detection microprocessor 30 can select the existing arc fault detection device in the prior art. Of course, in order to improve the accuracy of the judgment result, the chaotic properties of the fault arc can be referred to, and the relevant judgment rules required in the fault arc judgment process can be extracted according to the chaos identification idea. Therefore, the present application can pre-set the arc fault judgment rules in the arc fault detection microprocessor 30. When the sampling current output by the current sampling circuit 20 meets the above rules, it is determined that a fault arc occurs in the electrical equipment. In order to better formulate the above judgment rules, the applicant has collected a large amount of arc signal data in advance, established a fault arc database, and selected as many loads as possible. By analyzing the fault arc waveforms under various loads, the general and special properties of the working current when a fault arc occurs in the electrical equipment are summarized, providing a basic guarantee for the analysis of the arc fault. The applicant found through analysis that the characteristics of the fault arc can be summarized as follows:

[0051] (1) The arc current is no longer periodic. The waveform is incomplete in some current cycles, and the current waveforms in adjacent cycles are quite different.

[0052] (2) The arc current is not symmetrical, and the waveforms of the positive and negative half cycles in the same cycle are quite different.

[0053] (3) There is a period of time when the arc current is zero at the zero-crossing point, which is called the "zero-off time".

[0054] (4) There are a large number of high-frequency harmonics in the arc current. During the arc burning process, the arc current has local high-frequency interference. At the moment when the arc is initially turned on, there are high-frequency pulses in the current. This phenomenon is more obvious in circuits with inductive and capacitive loads.

[0055] (5) There is a moment of current mutation in the arc current near the zero point.

[0056] (6) The arc current is slightly smaller than the normal current amplitude.

[0057] When the current of the characteristic quantity appears in the working current of the electrical equipment, it indicates that a fault arc occurs in the electrical equipment, and the circuit breaker protector 10 is controlled to cut off the power supply to the electrical equipment for protection.

[0058] Specifically, the arc fault detection microprocessor 30 is configured to: obtain the sampled current output by the current sampling circuit 20, and when the sampled current meets any one of the preset judgment rules, control the circuit breaker to cut off the power supply to the electrical equipment;

[0059] The preset judgment rules include: the sampling current waveform in the current cycle is inconsistent with the current waveform in the adjacent cycle, the sampling current waveform in the current cycle is not symmetrical, the sampling current remains at 0 for a period of time exceeding a preset period, high-frequency harmonics appear in the sampling current, and the duration of the high-frequency harmonics exceeds a set threshold, a sudden current occurs in a preset time interval with the zero crossing point as the middle time point, and / or the amplitude of the sampling current is less than a set amplitude.

[0060] In the technical solution disclosed in another embodiment of this application, see Figure 9 When determining whether an arc fault occurs in an electrical device, the arc fault detection microprocessor 30 is specifically configured to:

[0061] Step S101: performing FFT transformation on the sampled current of one cycle;

[0062] Step S102: Calculate the modulus of each harmonic;

[0063] The sampling frequency of the current sampling circuit can be designed to be A times the power frequency, so a sequence of length A is processed to obtain A harmonic coefficients, and then the modulus value of each harmonic is calculated;

[0064] Step S103: Calculate the eigenvector;

[0065] In this step, due to the conjugate symmetry of DFT, only the collected A / 2 harmonic coefficients are retained. The above A / 2 harmonic coefficients refer to the effective values of the DC component, fundamental wave and (A / 2)-1 harmonic component of the sampled current. The above A / 2 harmonic coefficients are normalized to obtain the effective value of the harmonic. The retained harmonic effective value is divided by the effective value of the fundamental wave, and the fundamental wave component is removed to calculate the harmonic characteristic vector with a length of (A / 2)-1. The characteristic vector contains the signal waveform information. Harmonic coefficient modulus: P(n), n = 1, 2, ..., (A / 2)-1; characteristic vector: X(n) = P(n) / P(1), extract the characteristic vector;

[0066] Step S104: When an arc is detected, the type of arc is determined. When an abnormal fault arc is detected, step S105 is executed. When an abnormal arc is detected, step S106 is executed.

[0067] In this step, by calculating the magnitude of each harmonic component, the waveform information of the sampled current and the degree of waveform distortion are detected, thereby identifying whether a fault arc occurs in the electrical equipment;

[0068] Step S105: determining whether the number of occurrences of the abnormal arc within a preset time period reaches a set value, if yes, executing step S107;

[0069] Step S106: controlling the circuit breaker to disconnect;

[0070] Step S107: Control the device to enter a shutdown protection state and determine whether the abnormal arc disappears. If not, execute step S106.

[0071] In another embodiment of the present application, considering that arc faults in certain states do not affect the operation of electrical equipment or cause little damage to the electrical equipment, it is not necessary to perform power-off protection on the electrical equipment. The arc fault detection microprocessor 30 may be further configured as follows:

[0072] When it is determined based on the sampled current that a fault arc occurs in the electrical equipment, it is determined whether the fault arc is a first type of fault arc. If so, the circuit breaker 10 is controlled to cut off the power to the electrical equipment for protection. If not, the counter and timer start timing. When the timer reaches the set time, it is determined whether the count value of the counter is greater than the set value. If it is greater than the set value, the circuit breaker 10 is controlled to cut off the power to the electrical equipment for protection. The first type of fault arc is a preset fault arc that can cause greater harm to the electrical equipment.

[0073] In order to improve the accuracy of the detection result of the arc fault detection microprocessor 30 and prevent it from making erroneous judgments due to interference signals in the sampled current, see Figure 2 The technical solutions disclosed in the above embodiments of the present application may further include:

[0074] A signal modulation circuit 40 and an analog-to-digital conversion circuit 50 are arranged between the current detection circuit 10 and the arc detection microprocessor 30, wherein the signal modulation circuit 40 is used to modulate the sampling current collected by the current sampling circuit, and the analog-to-digital conversion circuit 50 is used to convert the modulated sampling current into a digital signal that is convenient for the arc detection microprocessor 30 to judge.

[0075] When the arc fault protection device of the electric equipment is used to protect the electric equipment, the above device can control the circuit breaker 10 to shut down only when a fault arc occurs in the electric equipment. When no fault arc occurs in the electric equipment, the user cannot actively determine whether the arc fault protection device of the electric equipment can normally respond to the fault arc of the electric equipment. When the arc fault protection device of the user's electric equipment cannot respond to the fault arc and the user does not discover it in time, when a fault arc occurs in the electric equipment, it may directly cause the electric equipment to catch fire. For this, see Figure 2 The above-mentioned device disclosed in the above-mentioned embodiment of the present application may further include:

[0076] The test circuit 60 is configured to output a simulated arc fault current signal to the arc detection microprocessor 30. Designers configure one or more different types of arc fault signals in the test circuit 60. When a user triggers the test circuit 60, the test circuit 60 outputs an arc fault signal matching the user's operation to the signal modulation circuit 40, the analog-to-digital conversion circuit 50, or directly to the arc detection microprocessor 30. If the circuit breaker 10 trips after the user triggers the test circuit 60, this indicates that the arc fault protection device for the electrical equipment is functioning properly.

[0077] In the technical solution disclosed in the above embodiment of the present application, the type of the circuit breaker 10 can be selected according to the user's needs. For example, it can be an electromagnetic holding relay. When the arc detection microprocessor 30 determines that a fault arc occurs in the electrical equipment, the arc detection microprocessor 30 may output only a momentary level signal. Conventional circuit breakers are difficult to directly respond to the level signal to perform power-off protection. For this, see Figure 2 The technical solutions disclosed in the above embodiments of the present application may further include:

[0078] A circuit breaker drive circuit 70 is arranged between the output end of the arc fault detection microprocessor 30 and the control end of the circuit breaker 10. The circuit breaker drive circuit 70 is used to obtain a trigger signal output by the arc fault detection microprocessor 30 to characterize the occurrence of a fault current in the electrical equipment. After obtaining the trigger signal, the circuit breaker drive circuit 70 outputs a drive signal to the circuit breaker 10 to drive the circuit breaker 10 to disconnect and perform power-off protection on the electrical equipment.

[0079] In the technical solution disclosed in the above embodiment of the present application, in order to ensure safer and more reliable power outage of the equipment, the circuit breaker 10 can be an electromagnetic holding relay. In this case, the circuit breaker drive circuit 70 is an electromagnetic holding relay drive circuit. The electromagnetic holding relay drive circuit is used to drive the electromagnetic holding relay to perform a tripping action after obtaining the trigger signal output by the arc fault detection microprocessor 30, so as to physically disconnect the power between the electrical equipment and the power supply, improve the reliability of power outage, and effectively reduce the possibility of users accidentally getting an electric shock when repairing electrical equipment.

[0080] In the solutions disclosed in the above embodiments of this application, see Figure 2 , is also configured with a power supply module 90 for supplying power to each working module. The power supply module 90 may include: a switching power supply 91 and a voltage conversion circuit 92. The voltage conversion module 92 is used to convert the voltage output by the switching power supply 91 into the working voltage required by each working module.

[0081] During operation, if electrical equipment is in a leakage state, overcurrent state, overvoltage state, undervoltage state or short circuit state for a long time, it may cause irreparable damage to the equipment. In order to provide more stringent protection for the electrical equipment, see Figure 2 , the above scheme may also include:

[0082] The leakage detection circuit 80, the overcurrent detection circuit 81, the overvoltage detection circuit 82, the undervoltage detection circuit 83 and / or the short-circuit detection circuit 84, and each of the above circuits can perform relevant fault judgment on the electrical equipment through the sampling current detected by the current sampling circuit 20. When it is judged that the electrical equipment is in a fault state, the circuit breaker 10 is controlled to cut off the power to the electrical equipment. Among them, when the leakage detection circuit 80, the overcurrent detection circuit 81, the overvoltage detection circuit 82, the undervoltage detection circuit 83 and the short-circuit detection circuit 84 judge that the electrical equipment is in a fault state, a control signal for controlling the disconnection of the circuit breaker 10 can be directly output to the circuit breaker 10. Of course, it can also be controlled by the The circuit breaker drive circuit 70 controls the circuit breaker 10 to disconnect. Of course, it can also send the control signal to the arc detection microprocessor 30, and the arc detection microprocessor 30 controls the circuit breaker 30 to perform power-off protection on the electrical equipment. At this time, the arc detection microprocessor 30 is configured to control the circuit breaker 10 to perform power-off protection on the electrical equipment directly or through the circuit breaker drive circuit 70 when a fault arc is detected in the electrical equipment or the control signal output by the electrical detection circuit 80, the overcurrent detection circuit 81, the overvoltage detection circuit 82, the undervoltage detection circuit 83 and / or the short circuit detection circuit 84 is obtained.

[0083] To simplify the field environment, see Figure 3 and Figure 4 In the above solution of the present application, the circuit breaker drive circuit 70 and the arc detection microprocessor 30 can communicate via a wireless network, that is, the above solution may further include:

[0084] A first wireless communication module W1 connected to the arc detection microprocessor 30, wherein the wireless communication module W1 has at least a built-in wireless signal transmitter;

[0085] A second wireless communication module W2 connected to the circuit breaker drive circuit 70, wherein Figure 4 In the embodiment, the first wireless communication module W1 is a wireless communication module built into the electrical device, and the second wireless communication module has at least a built-in wireless signal receiver, which is used to obtain, via a wireless network, a control signal output by the wireless signal transmitter for controlling the operating state of the circuit breaker 10. When the electrical device is a smart device capable of remote control, the first wireless communication module W1 can be the wireless communication module built into the electrical device.

[0086] See also Figure 5-Figure 8In the technical solution disclosed in the above embodiment of the present application, the circuit breaker protector can be integrally packaged with the power plug of the electrical equipment, and these components are packaged together. The other modules in the arc fault protection device of the electrical equipment can be integrated on the same PCB circuit board and installed in a set protective shell. When the arc fault protection device of the electrical equipment fails, in order to facilitate the user to replace the arc fault protection device of the electrical equipment, it can be placed independently of the electrical equipment; of course, in order to simplify the on-site environment, the circuit breaker 10, the circuit breaker drive circuit 70 and the power plug in the arc fault protection device of the electrical equipment are integrally packaged, and other components in the arc fault protection device of the electrical equipment can be integrated in the same PCB circuit board, and the circuit board is installed inside the electrical equipment. At this time, the communication line between the arc detection microprocessor 30 and the circuit breaker drive circuit 70 can be set in the power cord of the electrical equipment; of course, it should be noted that when wireless communication is carried out between the circuit breaker drive circuit 70 and the arc detection microprocessor 30, the second wireless communication module W2 also needs to be integrally packaged together with the power plug, the circuit breaker and the circuit breaker drive circuit.

[0087] To more accurately protect electrical equipment, the arc fault protection device for electrical equipment may be equipped with multiple current detection circuits, each of which detects the operating current of a predetermined functional module in the electrical equipment. For example, if the electrical equipment is an air conditioner, the predetermined functional module may be the air conditioner's motor, electric heater, and compressor. Of course, multiple arc fault protection devices for electrical equipment may also be provided to provide fault protection for each functional module in the electrical equipment. In this case, each arc fault protection device for electrical equipment shares a circuit breaker 10, a short-circuit protector drive circuit 70, and a second wireless communication module W2.

[0088] Furthermore, in the above scheme, when fault judgment needs to be performed on multiple preset functional modules, due to the different types of functional modules, the judgment rules for judging whether an arc fault occurs in the functional module are also different. Therefore, in the above scheme, the arc fault detection microprocessor 30 is also used to: calculate the harmonic characteristic vector of the normal current sampled by the current sampling circuit 20 and compare it with the pre-stored harmonic characteristic vectors of all functional modules, determine the functional module with the smallest square difference, and call the judgment rule matching the functional module as the basis for judging whether a fault arc occurs in the functional module.

[0089] In the technical solution disclosed in one embodiment of the present application, when an electrical device fails, in order to be able to promptly remind the user, the above solution may also include a network server for obtaining a fault signal output when the arc detection microprocessor 30 detects an arc fault in the electrical device. When the fault signal is obtained, an equipment fault alarm signal is output to the user terminal according to a preset address. The user terminal may be a mobile phone, a PC, or other device.

[0090] The arc fault protection device for electrical equipment can be wirelessly connected to a residential fire alarm center and used as a fire warning. Specifically, when the circuit breaker protector 10 is controlled to perform circuit breaker protection on the electrical equipment, a prompt signal is output to the residential fire alarm center.

[0091] At the same time, the arc fault protection device for the electrical equipment may also have a built-in smoke or gas detection sensor, which outputs an alarm signal when smoke or gas is detected during arc combustion.

[0092] It can be understood that in the above scheme, the arc detection microprocessor 30 is also used to generate and output a fault signal to the network server when an arc fault is detected in the electrical equipment, wherein the fault signal may include: equipment type information, equipment address information, type information of the functional module where the fault occurs. After obtaining the fault signal, the network server parses the fault signal to obtain the above-mentioned parameter information, and then obtains the preset address information matching the equipment address information from the preset mapping table, and outputs an alarm signal to the user end matching the preset address information. The alarm signal may include: equipment type information, type information of the functional module where the fault occurs, and type information of the fault. The fault type may refer to a fault such as an arc fault, overcurrent, overvoltage or undervoltage in the equipment. Of course, the preset address information may also be directly included in the alarm signal.

[0093] Corresponding to the above-mentioned arc fault protection device for electrical equipment, the present application also discloses an electrical equipment control system, in which the electrical equipment arc fault protection device disclosed in any one of the above-mentioned embodiments of the present application can be applied, wherein the electrical equipment can refer to equipment such as air conditioners and refrigerators.

[0094] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0095] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An arc fault protection device for electrical equipment, characterized in that: include: Circuit breaker protector installed on the power supply line of electrical equipment; A current detection circuit for detecting the operating current of an electrical device; an arc detection microprocessor having an input end connected to the output end of the current detection circuit, and an output end of the arc fault detection microprocessor connected to the control end of the circuit breaker; The arc fault detection microprocessor is configured to: obtain a sampled current output by a current sampling circuit, and when the sampled current meets any one of the preset judgment rules, control the circuit breaker to cut off the power supply to the electrical equipment for protection; The preset judgment rules include: the sampling current waveform in the current cycle is inconsistent with the current waveform in the adjacent cycle, the sampling current waveform in the current cycle is not symmetrical, the sampling current remains at 0 for a period of time exceeding a preset period, high-frequency harmonics appear in the sampling current, and the duration of the high-frequency harmonics exceeds a set threshold, a sudden change in current exists within a preset time interval with the zero crossing point as the middle time point, and / or the amplitude of the sampling current is less than a set amplitude; The arc fault detection microprocessor is further configured to: Perform FFT transformation on the sampling current of one cycle; Calculating the modulus of each harmonic: The sampling frequency of the current sampling circuit is designed to be A times the power frequency, so a sequence of length A is processed to obtain A harmonic coefficients, and then the modulus of each harmonic is calculated; Calculate the eigenvector: retain the collected A / 2 harmonic coefficients. The A / 2 harmonic coefficients refer to the effective values of the DC component, fundamental wave, and (A / 2)-1 harmonic component of the sampled current. Normalize the above A / 2 harmonic coefficients to obtain the harmonic effective value. Divide the retained harmonic effective value by the fundamental effective value, remove the fundamental component, and calculate the harmonic eigenvector with a length of (A / 2)-1. The eigenvector contains the signal waveform information. When an arc is detected, the type of the arc is determined; When an abnormal fault arc is detected in the equipment, it is determined whether the number of abnormal arc occurrences within a preset time period reaches a set value. If so, the equipment is controlled to enter a shutdown protection state, and it is determined whether the abnormal arc disappears. If not, the circuit breaker is controlled to disconnect. When an abnormal arc is detected in the equipment, the circuit breaker is controlled to disconnect.

2. The arc fault protection device for electrical equipment according to claim 1, characterized in that: Also includes: A signal modulation circuit and an analog-to-digital conversion circuit are provided between the current detection circuit and the arc detection microprocessor.

3. The arc fault protection device for electrical equipment according to claim 1, characterized in that: Also includes: The test circuit is used to output a simulated fault arc current signal to the arc detection microprocessor.

4. The arc fault protection device for electrical equipment according to claim 1, characterized in that: Also includes: A circuit breaker drive circuit is provided between the output terminal of the arc fault detection microprocessor and the control terminal of the circuit breaker.

5. The arc fault protection device for electrical equipment according to claim 4, characterized in that: The circuit breaker is an electromagnetic holding relay, and the circuit breaker drive circuit is an electromagnetic holding relay drive circuit. The electromagnetic holding relay drive circuit is used to drive the electromagnetic holding relay to trip according to the trigger signal output by the arc fault detection microprocessor.

6. The arc fault protection device for electrical equipment according to claim 1, characterized in that: Also includes: A leakage detection circuit, an overcurrent detection circuit, an overvoltage detection circuit, an undervoltage detection circuit and / or a short circuit detection circuit connected to the arc detection microprocessor for detecting electrical equipment.

7. The arc fault protection device for electrical equipment according to claim 4, characterized in that: Also includes: a wireless signal transmitter connected to the arc detection microprocessor; A wireless signal receiver connected to the circuit breaker drive circuit, the wireless signal receiver is used to obtain the control signal output by the wireless signal transmitter for controlling the working state of the circuit breaker through a wireless network.

8. The arc fault protection device for electrical equipment according to claim 7, characterized in that: The wireless signal transmitter is a wireless signal transmitter in the wireless communication module of the electric device.

9. The arc fault protection device for electrical equipment according to claim 7, characterized in that: There are multiple current detection circuits, and each current detection circuit detects the operating current of a preset functional module in the electrical device.

10. The arc fault protection device for electrical equipment according to claim 1, characterized in that: Also includes: The network server is used to obtain a fault signal generated when the arc detection microprocessor detects an arc fault in an electrical device, and output an equipment fault alarm signal to a user terminal according to a preset address.

11. An electrical equipment control system, applied to electrical equipment, characterized in that: include: The arc fault protection device for electrical equipment according to any one of claims 1 to 10.

12. The electric equipment control system according to claim 11, characterized in that: The electrical equipment is an air conditioner.

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