Arc detection device and electrical protection system

Abstract

The utility model provides an electric arc detection device and an electric protection system. The electric arc detection device comprises a voltage conditioning circuit, an electric arc mutual inductor, an electric arc current conditioning circuit and a control circuit. The voltage conditioning circuit is electrically connected with the control circuit and used for being electrically connected with a main loop, and is used for collecting loop voltage of the main loop for arc detection and outputting the loop voltage to the control circuit; the arc mutual inductor is electrically connected with the control circuit through the arc current conditioning circuit, and the arc current conditioning circuit is used for accessing the arc current, collected by the arc mutual inductor, of the main loop and outputting arc current conditioning voltage used for arc detection to the control circuit. Therefore, the control circuit can perform comprehensive judgment based on the arc current conditioning voltage obtained in the current aspect and the loop voltage in the voltage aspect, so that the arc can be detected more accurately, and the accuracy of arc detection is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electrical protection technical field, concretely relates to an arc detection device and electrical protection system. BACKGROUND

[0002] The arc detection is mainly used for preventing arc causes, when the arc appears in the loop, the arc detection can determine that the arc appears in the loop in time, thereby facilitating to take relevant processing measures, such as power-off operation, and finally realizing the risk control of arc.

[0003] Because the occurrence of arc has no certain relationship with the current size in the loop, the traditional overcurrent protection device cannot effectively prevent the arc fault from causing fire, and finally leads to the low accuracy of arc detection. UTILITY MODEL CONTENTS

[0004] In view of the deficiencies in the prior art, the utility model provides an arc detection device and electrical protection system.

[0005] In one embodiment, the utility model provides an arc detection device, and the arc detection device comprises a voltage conditioning circuit, an arc mutual inductor, an arc current conditioning circuit and a control circuit.

[0006] The voltage conditioning circuit is electrically connected with the control circuit and is used to be electrically connected with the main loop, is used to collect the loop voltage of the main loop for arc detection and is output to the control circuit.

[0007] The arc mutual inductor is electrically connected with the control circuit through the arc current conditioning circuit, and the arc current conditioning circuit is used to input the arc current of the main loop collected by the arc mutual inductor and output the arc current conditioning voltage for arc detection to the control circuit.

[0008] In one embodiment, the voltage conditioning circuit comprises a first voltage conditioning unit.

[0009] The first voltage conditioning unit is electrically connected with the control circuit and is used to be electrically connected with the main loop, is used to output the first loop voltage meeting the first voltage frequency in the loop voltage to the control circuit for arc detection.

[0010] In one embodiment, the first voltage conditioning unit comprises a first high-pass filter and a first non-inverting amplifier, the input end of the first high-pass filter is used to be electrically connected with the main loop, the output end of the first high-pass filter is electrically connected with the input end of the first non-inverting amplifier, and the output end of the first non-inverting amplifier is electrically connected with the control circuit.

[0011] In one embodiment, the voltage conditioning circuit further comprises a second voltage conditioning unit.

[0012] The second voltage conditioning unit is electrically connected with the control circuit and used for being electrically connected with the main loop, and is used for outputting a second loop voltage in the loop voltage which meets a second voltage frequency to the control circuit for voltage protection.

[0013] In one embodiment, the second voltage conditioning unit comprises a voltage dividing resistor and a first inverting amplifier, a first end of the voltage dividing resistor is used for being electrically connected with the main loop, a second end of the voltage dividing resistor is electrically connected with an input end of the first inverting amplifier, and an output end of the first inverting amplifier is electrically connected with the control circuit.

[0014] In one embodiment, the arc current conditioning circuit comprises an input unit and an arc current conditioning unit;

[0015] The input unit is electrically connected with the arc transformer and electrically connected with the control circuit through the arc current conditioning unit;

[0016] The input unit is used for converting the arc current into an arc voltage and outputting to the arc current conditioning unit;

[0017] The arc current conditioning unit is used for conditioning the arc voltage and outputting an arc current conditioning voltage to the control circuit.

[0018] In one embodiment, the input unit comprises a sampling resistor and a second non-inverting amplifier;

[0019] The sampling resistor is respectively electrically connected with the arc transformer and an input end of the second non-inverting amplifier, and an output end of the second non-inverting amplifier is electrically connected with the conditioning unit.

[0020] In one embodiment, the arc current conditioning unit comprises a first conditioning sub-unit and a second conditioning sub-unit, and the arc current conditioning voltage comprises a first current conditioning voltage and a second current conditioning voltage;

[0021] The first conditioning sub-unit is respectively electrically connected with the input unit and the control circuit, and is used for conditioning a part in the arc voltage which meets a first current frequency and feeding back the first current conditioning voltage to the control circuit for arc detection;

[0022] The second conditioning sub-unit is respectively electrically connected with the input unit and the control circuit, and is used for conditioning a part in the arc voltage which meets a second current frequency and feeding back the second current conditioning voltage to the control circuit for arc detection.

[0023] In one embodiment, the arc current conditioning unit further comprises a third conditioning sub-unit, and the arc current conditioning voltage further comprises a third current conditioning voltage;

[0024] The third conditioning sub-unit is respectively electrically connected with the input unit and the control circuit, and is used for conditioning a part in the arc voltage which meets a third current frequency and feeding back the third current conditioning voltage to the control circuit for current detection.

[0025] In one embodiment, the first conditioning subunit comprises a second high-pass filter and a third non-inverting amplifier, an input end of the second high-pass filter is electrically connected with the input unit, an output end of the second high-pass filter is electrically connected with an input end of the third non-inverting amplifier, and an output end of the third non-inverting amplifier is electrically connected with the control circuit;

[0026] And / or, the second conditioning subunit comprises a first narrow-band pass filter, a fourth non-inverting amplifier, a second narrow-band pass filter and a fifth non-inverting amplifier, an input end of the first narrow-band pass filter is electrically connected with the input unit, an output end of the first narrow-band pass filter is electrically connected with an input end of the fourth non-inverting amplifier, an output end of the fourth non-inverting amplifier is electrically connected with an input end of the second narrow-band pass filter, an output end of the second narrow-band pass filter is electrically connected with an input end of the fifth non-inverting amplifier, and an output end of the fifth non-inverting amplifier is electrically connected with the control circuit;

[0027] And / or, the third conditioning subunit comprises a first resistor, a second resistor, a capacitor and a sixth non-inverting amplifier, a first end of the first resistor is electrically connected with the input unit, a second end of the first resistor is electrically connected with a first end of the second resistor and is electrically connected with an output end of the sixth non-inverting amplifier through the capacitor, a second end of the second resistor is electrically connected with an input end of the sixth non-inverting amplifier, and an output end of the sixth non-inverting amplifier is further electrically connected with the control circuit.

[0028] In a second aspect, in one embodiment, the utility model provides an electrical protection system, including switching device, drive circuit and arc detection device in any one of above-mentioned embodiments;

[0029] The switching device is connected in series in the main loop and is electrically connected with the control circuit through the drive circuit, and is used for being turned off when the arc appears in the main loop based on the control of the control circuit.

[0030] In one embodiment, the electrical protection system further comprises a zero sequence transformer and a leakage current conditioning circuit;

[0031] The zero sequence transformer is electrically connected with the control circuit through the leakage current conditioning circuit, and the leakage current conditioning circuit is used for connecting the leakage current of the main loop collected by the zero sequence transformer and feeding back the leakage current conditioning voltage for leakage protection to the control circuit.

[0032] In one embodiment, the leakage current conditioning circuit comprises a second non-inverting amplifier;

[0033] An input end of the second non-inverting amplifier is electrically connected with the zero sequence transformer, and an output end of the second non-inverting amplifier is electrically connected with the control circuit.

[0034] By the arc detection device and the electrical protection system, the arc mutual inductor and the corresponding arc current conditioning circuit are used to realize the detection of the main circuit in the current aspect, and on this basis, the voltage conditioning circuit is used to realize the detection of the main circuit in the voltage aspect, so that the control circuit can comprehensively judge based on the arc current conditioning voltage obtained in the current aspect and the loop voltage in the voltage aspect, thereby more accurately detecting the arc and improving the accuracy of arc detection. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0036] Figure 1 The structural schematic diagram of the electrical protection system containing the arc detection device in an embodiment of the present application;

[0037] Figure 2 The structural schematic diagram of the respective compositions of the voltage conditioning circuit and the arc current conditioning circuit in an embodiment of the present application;

[0038] Figure 3 The specific circuit implementation schematic diagram of the first voltage conditioning unit and the second voltage conditioning unit in an embodiment of the present application;

[0039] Figure 4 The specific circuit implementation schematic diagram of the input unit in an embodiment of the present application;

[0040] Figure 5 The specific circuit implementation schematic diagram of the first conditioning subunit in an embodiment of the present application;

[0041] Figure 6 The specific circuit implementation schematic diagram of the second conditioning subunit in an embodiment of the present application;

[0042] Figure 7 The specific circuit implementation schematic diagram of the third conditioning subunit in an embodiment of the present application;

[0043] Figure 8 The specific circuit implementation schematic diagram of the leakage current conditioning circuit in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited. In the present application, the word "exemplary" is used to mean "serving as an example, instance, or illustration". Any embodiment described as "exemplary" in the present application is not necessarily construed as being more preferred or advantageous than other embodiments. The following description is given in order to enable any person skilled in the art to implement and use the present application. In the following description, details are listed for the purpose of explanation. It should be understood that those skilled in the art can realize the present application without using these specific details. In other examples, well-known structures and processes will not be described in detail in order to avoid unnecessary details making the description of the present application obscure. Therefore, the present application is not intended to be limited to the shown embodiments, but is consistent with the broadest scope of principles and features disclosed.

[0046] In one embodiment, as shown in the first aspect, Figure 1 The arc detection circuit includes a voltage conditioning circuit, an arc transformer, an arc current conditioning circuit, and a control circuit.

[0047] In this embodiment, the control circuit includes an MCU, and in other embodiments, the control circuit can also use other types of devices.

[0048] The voltage conditioning circuit is electrically connected with the MCU and is electrically connected with the main loop formed by the live wire L and the neutral wire N, and is used to collect the loop voltage of the main loop for arc detection and output to the control circuit.

[0049] The input end of the voltage conditioning circuit is electrically connected with the live wire L and the neutral wire N respectively, and the output end of the voltage conditioning circuit is electrically connected with the analog-digital conversion interface ADC and the comparator interface CMP of the MCU respectively.

[0050] For the voltage aspect of the main loop, on the one hand, the MCU can access the loop voltage through the analog-digital conversion interface ADC, thereby obtaining the voltage characteristics of the main loop for subsequent arc detection judgment; on the other hand, the MCU can access the loop voltage through the comparator interface CMP, thereby determining whether the main loop has overvoltage, undervoltage and other faults and performing zero-crossing point judgment.

[0051] The arc current transformer is electrically connected with the MCU through the arc current conditioning circuit, and the arc current conditioning circuit is used to access the arc current of the main loop collected by the arc current transformer and output the arc current conditioning voltage for arc detection to the control circuit.

[0052] The input end of the arc current conditioning circuit is electrically connected with the live wire L and the neutral wire N respectively, and the output end of the arc current conditioning circuit is electrically connected with the analog-digital conversion interface ADC and the comparator interface CMP of the MCU respectively.

[0053] For the current aspect of the main loop, on the one hand, the MCU can access the arc current conditioning voltage through the analog-digital conversion interface ADC, thereby obtaining the current characteristics of the main loop for subsequent arc detection judgment; on the other hand, the MCU can access the arc current conditioning voltage through the comparator interface CMP, thereby performing current amplitude judgment of the main loop.

[0054] The MCU can simultaneously obtain the voltage characteristics and the current characteristics of the main loop, thereby performing comprehensive judgment, and can more reliably realize arc detection.

[0055] Through the above arc detection device, the arc current transformer and the corresponding arc current conditioning circuit are used to realize the detection of the main loop in the current aspect, and on this basis, the voltage conditioning circuit is used to realize the detection of the main loop in the voltage aspect, so that the control circuit can perform comprehensive judgment based on the arc current conditioning voltage obtained in the current aspect and the loop voltage in the voltage aspect, thereby more accurately detecting the arc and improving the accuracy of arc detection.

[0056] As shown in FIG. Figure 1 In one embodiment, the arc detection device further includes a power supply circuit and a user button.

[0057] In one aspect, the main circuit is electrically connected to the power supply circuit through the user button at the front end of the switching device K1, and in another aspect, the main circuit is directly electrically connected to the power supply circuit at the rear end of the switching device K1.

[0058] When the arc detection device is not started, the switching device K1 is in an open state, and the power supply circuit cannot directly take power from the main circuit. If the user controls the user button to be in a closed state, the power supply circuit can take power from the main circuit through the user button, thereby supplying power to the MCU, the voltage conditioning circuit, and the arc current conditioning circuit, and the arc detection device is started.

[0059] As shown in FIG. 1, Figure 2 In one embodiment, the voltage conditioning circuit includes a first voltage conditioning unit and a second voltage conditioning unit.

[0060] The first voltage conditioning unit is electrically connected to the MCU and is used to be electrically connected to the main circuit, and is used to output a first loop voltage in the loop voltage that meets a first voltage frequency to the MCU for arc detection.

[0061] The first voltage frequency can be understood as a high-frequency signal in the voltage aspect of the main circuit. The high-frequency voltage signal in the main circuit is usually superimposed on the original voltage signal, and the corresponding amplitude is small, so the first voltage conditioning unit can further play a signal amplification role in addition to the frequency filtering role.

[0062] The input end of the first voltage conditioning unit is electrically connected to the live wire L and the neutral wire N, respectively, and the output end of the first voltage conditioning unit is electrically connected to the analog-to-digital conversion interface ADC of the MCU and the comparator interface CMP.

[0063] For the high-frequency part of the voltage, on the one hand, the MCU can access the corresponding first loop voltage through the analog-to-digital conversion interface ADC, thereby obtaining the frequency characteristics of the high-frequency voltage of the main circuit; on the other hand, the MCU can access the first loop voltage through the comparator interface CMP, thereby obtaining the amplitude characteristics of the high-frequency voltage of the main circuit; so that the MCU can refer to the frequency and amplitude characteristics of the high-frequency voltage when judging whether the arc appears in the main circuit, thereby improving the accuracy of detection.

[0064] The second voltage conditioning unit is electrically connected to the MCU and is used to be electrically connected to the main circuit, and is used to output a second loop voltage in the loop voltage that meets a second voltage frequency to the MCU for voltage protection.

[0065] The second voltage frequency can be understood as a low-frequency signal in the voltage aspect of the main circuit. The low-frequency voltage signal in the main circuit has a small amplitude, so the second voltage conditioning unit can further play a signal reduction role in addition to the frequency filtering role.

[0066] The input end of the second voltage conditioning unit is electrically connected with the live wire L and the neutral wire N respectively, and the output end of the second voltage conditioning unit is electrically connected with the analog-digital conversion interface ADC and the comparator interface CMP of the MCU respectively.

[0067] For the low-frequency part of the voltage, on the one hand, the MCU can access the corresponding second loop voltage through the analog-digital conversion interface ADC, so as to obtain the frequency characteristics of the low-frequency voltage of the main loop; on the other hand, the MCU can access the second loop voltage through the comparator interface CMP, so as to obtain the amplitude characteristics of the low-frequency voltage of the main loop; so that the MCU can simultaneously refer to the frequency and amplitude characteristics of the low-frequency voltage when judging whether the main loop has overvoltage, undervoltage and other faults and performing zero-crossing point judgment, thereby improving the reliability of protection.

[0068] As shown in Figure 3 In one embodiment, the first voltage conditioning unit includes a specific high-pass filter structure (for ease of description, it can be understood as a first high-pass filter, and in other embodiments, a specific structure such as a radio frequency transformer can also be used as the first high-pass filter) mainly composed of a capacitor C36 and a resistor R51, and a first non-inverting amplifier mainly composed of an operational amplifier U11A and a resistor R49. The first end of the capacitor C36 is used for electrical connection with the main loop to access the initial loop voltage L_ext. The second end of the capacitor C36 is electrically connected with the first end of the resistor R51 and is electrically connected with the non-inverting input end of the operational amplifier U11A through the resistor R27. The second end of the resistor R51 is connected with a reference voltage Vcm_+1.65V, grounded through the capacitor C33, and electrically connected with the first end of the resistor R49 through the resistor R48. The second end of the resistor R49 is electrically connected with the output end of the operational amplifier U11A. The output end of the operational amplifier U11A is also electrically connected with the MCU to output the first loop voltage Volt_HF.

[0069] The first high-pass filter composed of the above can allow high-frequency voltage signals to pass, such as allowing voltage signals with a frequency of 3.19 MHz or higher to pass.

[0070] As shown in Figure 3 The first voltage conditioning unit further includes a clamping diode D12, which is connected with the working voltage AVDD_+3.3V and the ground respectively.

[0071] The clamping diode D12 can clamp the amplitude of the passing high-frequency voltage signal between GND and +3.3V to protect the subsequent circuit.

[0072] In other embodiments, the first voltage conditioning unit can also use other specific circuit structures.

[0073] As shown in Figure 3 In one embodiment, the second voltage conditioning unit includes a voltage dividing resistor composed of resistors R54, R56, R57 and R59, and a first inverting amplifier mainly composed of resistor R58 and operational amplifier U11B.

[0074] The first end of resistor R54 is electrically connected to the main circuit to access the initial circuit voltage L_ext, the second end of resistor R54 is electrically connected to the inverting input terminal of operational amplifier U11B and the first end of resistor R58 through resistors R56, R57 and R59 connected in series, the second end of resistor R58 is electrically connected to the output terminal of operational amplifier U11B, and the output terminal of operational amplifier U11B is also electrically connected to the MCU to output the second circuit voltage Volt_AllFreg.

[0075] The resistors R54, R56, R57 and R59 in the voltage dividing resistor and the resistor R58 in the first inverting amplifier constitute a series voltage dividing resistor network to achieve the purpose of voltage reduction, so as to convert the amplitude of the low-frequency high-voltage signal (such as a 220V / 50Hz voltage signal) in the main circuit to a processable amplitude range.

[0076] In addition to low-frequency voltage signals, voltage signals of other frequencies are basically attenuated in the process of passing through the above resistor string, thereby achieving the effect of low-pass filtering.

[0077] As shown in Figure 3 The second voltage conditioning unit also includes a clamping tube D14, the function of which can be referred to the above embodiment, which will not be described here.

[0078] In other embodiments, the second voltage conditioning unit can also use other specific circuit structures.

[0079] As shown in Figure 2 In one embodiment, the arc current conditioning circuit includes an input unit and an arc current conditioning unit, and the arc current conditioning unit includes a first conditioning subunit, a second conditioning subunit and a third conditioning subunit.

[0080] The input unit is used to realize the conversion of current to voltage, and the first conditioning subunit, the second conditioning subunit and the third conditioning subunit are respectively used to condition the voltage output by the input unit in different ways to meet the subsequent processing requirements.

[0081] The input unit is electrically connected to the arc mutual inductor and is electrically connected to the MCU through the first conditioning subunit, the second conditioning subunit and the third conditioning subunit.

[0082] The arc current output by the arc mutual inductor is first input into the input unit for current-to-voltage conversion processing to obtain the corresponding arc voltage, and then the arc voltage is input into the first conditioning subunit, the second conditioning subunit and the third conditioning subunit respectively.

[0083] The first conditioning subunit is electrically connected with the input unit and the MCU respectively, and is used for conditioning the part of the arc voltage that meets the first current frequency and feeding back a first current conditioning voltage for arc detection to the MCU.

[0084] The first current frequency can be understood as a high-frequency signal of the main circuit in terms of current. The current signal in the main circuit corresponds to a small amplitude, so the first conditioning subunit can further play a signal amplification role in addition to the frequency screening role.

[0085] The output end of the first conditioning subunit is electrically connected with the analog-to-digital conversion interface ADC and the comparator interface CMP of the MCU respectively.

[0086] For the high-frequency part of the current, on the one hand, the MCU can access the corresponding first current conditioning voltage through the analog-to-digital conversion interface ADC, thereby obtaining the frequency characteristics of the high-frequency current of the main circuit; on the other hand, the MCU can access the first current conditioning voltage through the comparator interface CMP, thereby obtaining the amplitude characteristics of the high-frequency current of the main circuit; so that the MCU can refer to the frequency and amplitude characteristics of the high-frequency current when judging whether the arc appears in the main circuit, thereby improving the reliability of protection.

[0087] The second conditioning subunit is electrically connected with the input unit and the MCU respectively, and is used for conditioning the part of the arc voltage that meets the second current frequency and feeding back a second current conditioning voltage for arc detection to the MCU.

[0088] The second current frequency can be understood as a medium-frequency signal of the main circuit in terms of current. The current signal in the main circuit corresponds to a small amplitude, so the second conditioning subunit can further play a signal amplification role in addition to the frequency screening role.

[0089] The output end of the second conditioning subunit is electrically connected with the analog-to-digital conversion interface ADC and the comparator interface CMP of the MCU respectively.

[0090] For the intermediate frequency part of the current, on the one hand, the MCU can access the corresponding second current conditioning voltage through the analog-digital conversion interface ADC, so as to obtain the characteristics of the intermediate frequency current of the main circuit in terms of frequency; on the other hand, the MCU can access the second current conditioning voltage through the comparator interface CMP, so as to obtain the characteristics of the intermediate frequency current of the main circuit in terms of amplitude; so that the MCU can refer to the characteristics of the intermediate frequency current in terms of frequency and amplitude when judging whether the arc appears in the main circuit, thereby improving the reliability of protection.

[0091] The third conditioning subunit is electrically connected with the input unit and the MCU respectively, and is used for conditioning the part of the arc voltage that meets the third current frequency and feeding back the third current conditioning voltage for current detection to the MCU.

[0092] The third current frequency can be understood as a low frequency signal of the main circuit in terms of current. The current signal in the main circuit corresponds to a small amplitude, so the third conditioning subunit can further play a signal amplification role in addition to the role of frequency screening.

[0093] The output end of the third conditioning subunit is electrically connected with the analog-digital conversion interface ADC and the comparator interface CMP of the MCU respectively.

[0094] For the low frequency part of the current, the MCU can access the corresponding third current conditioning voltage through the analog-digital conversion interface ADC, so as to obtain the characteristics of the low frequency current of the main circuit in terms of frequency, which is different from the first conditioning subunit and the second conditioning subunit, and does not need to use the comparator interface CMP, so that the MCU can reduce the cost when detecting the current of the main circuit.

[0095] In this embodiment, the high frequency current and the intermediate frequency current are simultaneously referred to in the process of realizing arc detection, thereby further improving the accuracy of detection.

[0096] As shown in Figure 4 In one embodiment, the input unit includes a sampling resistor R12 and a second non-inverting amplifier mainly composed of a resistor R8 and an operational amplifier U5A.

[0097] The sampling resistor R12 is electrically connected with the arc mutual inductor to access the arc current ArcCT_IN+, and is also electrically connected with the non-inverting input end of the operational amplifier U5A. The resistor R8 is electrically connected with the inverting input end and the output end of the operational amplifier U5A respectively. The output end of the operational amplifier U5A is also electrically connected with the conditioning unit to output the arc voltage CT_AllFreg.

[0098] The sampling resistor R12 is used to convert the voltage drop generated by the arc current flowing through itself to obtain the corresponding initial voltage. After the initial voltage is amplified by devices such as the operational amplifier U5A, the corresponding arc voltage CT_AllFreg is obtained.

[0099] like Figure 5 As shown, in one embodiment, the first conditioning subunit includes a specific high-pass filter structure mainly composed of capacitor C8, capacitor C15 and resistor R24 ​​(for ease of description, it can be understood here as a second high-pass filter; in other embodiments, a specific structure such as an RF transformer can also be used as a second high-pass filter) and a third non-inverting amplifier mainly composed of resistor R3 and operational amplifier U5B.

[0100] The first terminal of capacitor C15 is electrically connected to the input unit through capacitor C8 to receive the arc voltage CT_AllFreg, and is electrically connected to the output terminal of operational amplifier U5B through resistor R13. The second terminal of capacitor C15 is electrically connected to the non-inverting input terminal of operational amplifier U5B and the first terminal of resistor R24. The second terminal of resistor R24 ​​is used to receive the reference voltage Vcm_+1.65V, is grounded through capacitor C7, and is electrically connected to the first terminal of resistor R3 through resistor R2. The second terminal of resistor R3 is electrically connected to the output terminal of operational amplifier U5B. The output terminal of operational amplifier U5B is also electrically connected to the MCU to output the first current conditioning voltage CT_HF.

[0101] The second high-pass filter described above allows high-frequency voltage signals to pass through, such as voltage signals with a frequency of 387kHz or higher.

[0102] In other embodiments, the first conditioning subunit may also employ other specific circuit structures.

[0103] like Figure 6 As shown, in one embodiment, the second conditioning subunit includes a specific narrowband pass filter structure mainly composed of resistor R37, capacitor C25, capacitor C29 and resistor R34 (for ease of description, it can be understood here as a first narrowband pass filter; in other embodiments, other specific structures can be used to implement the first narrowband pass filter), a fourth non-inverting amplifier mainly composed of resistor R29 and operational amplifier U9A, a specific narrowband pass filter structure mainly composed of resistor R36, capacitor C26, capacitor C28 and resistor R35 (for ease of description, it can be understood here as a second narrowband pass filter; in other embodiments, other specific structures can be used to implement the second narrowband pass filter), and a fifth non-inverting amplifier mainly composed of resistor R31 and operational amplifier U9B.

[0104] Specifically, the first terminal of capacitor C29 is electrically connected to the input unit through resistor R37 to receive the arc voltage CT_AllFreg, and is also electrically connected to the output of operational amplifier U9A through resistor R41, and to the first terminal of capacitor C25. The second terminal of capacitor C29 is electrically connected to the non-inverting input terminal of operational amplifier U9A and the first terminal of resistor R34. The second terminals of capacitor C25 and resistor R34 are used to receive the reference voltage Vcm_+1.65V, and are grounded through capacitor C61, and are also electrically connected to the first terminal of resistor R29 and the inverting input terminal of operational amplifier U9A through resistor R30. The second terminal of resistor R29 is electrically connected to the output terminal of operational amplifier U9A.

[0105] Specifically, the first terminal of capacitor C28 is electrically connected to the output terminal of operational amplifier U9A through resistor R36, and to the output terminal of operational amplifier U9B through resistor R42. It is also electrically connected to the first terminal of capacitor C26. The second terminal of capacitor C28 is electrically connected to the non-inverting input terminal of operational amplifier U9B and the first terminal of resistor R35. The second terminals of capacitor C26 and resistor R35 are used to connect to the reference voltage Vcm_+1.65V. They are also electrically connected to the first terminal of resistor R31 and the inverting input terminal of operational amplifier U9B through resistor R75. The second terminal of resistor R31 is electrically connected to the output terminal of operational amplifier U9B. The output terminal of operational amplifier U9B is also electrically connected to the MCU to output the second current conditioning voltage CT_MF.

[0106] The first and second narrowband pass filters described above can flatten the in-band combined gain between the two frequency points by selecting two appropriate frequency points and gains, thereby allowing intermediate frequency voltage signals to pass through, such as voltage signals with frequencies of 11.6KHz-139KHz.

[0107] In other embodiments, the second conditioning subunit may also employ other specific circuit structures.

[0108] like Figure 7 As shown, in one embodiment, the third conditioning subunit includes a first resistor R44, a second resistor R45, a capacitor C31, and a sixth non-inverting amplifier mainly composed of a resistor R47 and an operational amplifier U6B.

[0109] The first end of the first resistor R44 is electrically connected with the input unit to access the arc voltage CT_AllFreg, the second end of the first resistor R44 is electrically connected with the first end of the second resistor R45 and is electrically connected with the output end of the operational amplifier U6B through the capacitor C31, the second end of the second resistor R45 is electrically connected with the non-inverting input end of the operational amplifier U6B and is connected with the reference voltage Vcm_+1.65V through the capacitor C32, the capacitor C32 is also connected with the ground through the capacitor C37 and is electrically connected with the first end of the resistor R47 and the inverting input end of the operational amplifier U6B through the resistor R46, and the output end of the operational amplifier U6B is also electrically connected with the MCU to output the third current regulating voltage CT_LF.

[0110] In the process of passing through the first resistor R44 and the second resistor R45, the voltage signal of other frequencies except the low-frequency voltage signal is basically attenuated, so that the low-pass filtering effect is realized.

[0111] As shown in Figure 1 the second aspect, in one embodiment, the utility model provides an electrical protection system, including switching device K1, drive circuit and the arc detection device in any one of above-mentioned embodiments.

[0112] The switching device K1 is connected in series in the main loop composed of the live wire L and the neutral wire N and is electrically connected with the control circuit composed of the drive circuit and the MCU, is used for being controlled based on the MCU and being disconnected when the arc appears in the main loop.

[0113] When the MCU detects that the arc appears in the main loop, the switching device K1 is disconnected through the drive circuit, so that the power supply of the rear stage load is interrupted, and the electrical safety is guaranteed.

[0114] The switching device K1 includes but is not limited to electromagnetic switch and semiconductor switch, when the switching device K1 is the electromagnetic switch, the corresponding drive circuit adopts the magnetic flux driving mode.

[0115] Through the arc detection device contained in the above-mentioned electrical protection system, the arc current transformer and the corresponding arc current regulating circuit are used to realize the detection of the main loop in the current aspect, and on this basis, the voltage regulating circuit is used to realize the detection of the main loop in the voltage aspect, so that the control circuit can comprehensively judge based on the arc current regulating voltage obtained in the current aspect and the loop voltage in the voltage aspect, so that the arc is more accurately detected, and the accuracy of arc detection is improved.

[0116] As shown in Figure 1 in one embodiment, the electrical protection system further includes a zero sequence transformer and a leakage current regulating circuit.

[0117] The zero sequence transformer is electrically connected with the MCU through a leakage current conditioning circuit, and the leakage current conditioning circuit is used for connecting the leakage current of the main loop collected by the zero sequence transformer and feeding back a leakage current conditioning voltage for leakage protection to the control circuit.

[0118] When the MCU detects that the leakage current of the main loop exceeds a threshold value, the switching device K1 can also be opened through the driving circuit to realize electrical protection.

[0119] As shown in the figure, Figure 8 In one embodiment, the leakage current conditioning circuit mainly comprises a second inverting amplifier composed of a resistor R6 and an operational amplifier U6A.

[0120] The resistor R6 is electrically connected with the zero sequence transformer through a current limiting resistor R5 to connect the leakage current ZCT_IN+, and is electrically connected with the non-inverting input terminal of the operational amplifier U6A through a clamping tube D8 and is electrically connected with the inverting input terminal of the operational amplifier U6A, the second terminal of the resistor R6 is electrically connected with the output terminal of the operational amplifier U6A, and the output terminal of the operational amplifier U6A is also electrically connected with the MCU to output the leakage current conditioning voltage I_N.

[0121] The resistor R6 realizes current-to-voltage conversion to facilitate subsequent processing.

[0122] As shown in the figure, Figure 1 In one embodiment, the electrical protection system further comprises a leakage current simulation circuit, which is electrically connected with the zero sequence transformer and the MCU respectively, and is used to generate a test current for simulating leakage and output to the zero sequence transformer based on the control of the MCU, to detect whether the leakage protection function of the electrical protection system is normal.

[0123] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the detailed description of other embodiments above, which will not be repeated here.

[0124] The above provides a detailed introduction to the arc detection device and the electrical protection system, and the principle and implementation mode of the present application are described by applying specific examples; the above embodiment is only used to help understand the method and core idea of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, and the above description should not be understood as a limitation of the present application.

[0125] The technical features of the above embodiments can be combined arbitrarily, and in order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

Claims

1. An arc detection device, characterized in that, The arc detection circuit includes a voltage conditioning circuit, an arc transformer, an arc current conditioning circuit, and a control circuit. The voltage conditioning circuit is electrically connected to the control circuit and is used to be electrically connected to the main circuit, for acquiring the loop voltage of the main circuit used for arc detection and outputting it to the control circuit; The arc transformer is electrically connected to the control circuit through the arc current conditioning circuit. The arc current conditioning circuit is used to receive the arc current of the main circuit collected by the arc transformer and output an arc current conditioning voltage for arc detection to the control circuit.

2. The arc detection device according to claim 1, characterized in that, The voltage conditioning circuit includes a first voltage conditioning unit; The first voltage conditioning unit is electrically connected to the control circuit and is used to be electrically connected to the main circuit. It is used to output the first circuit voltage that conforms to the first voltage frequency to the control circuit for arc detection.

3. The arc detection device according to claim 2, characterized in that, The first voltage conditioning unit includes a first high-pass filter and a first non-inverting amplifier. The input terminal of the first high-pass filter is electrically connected to the main circuit, the output terminal of the first high-pass filter is electrically connected to the input terminal of the first non-inverting amplifier, and the output terminal of the first non-inverting amplifier is electrically connected to the control circuit.

4. The arc detection device according to claim 2, characterized in that, The voltage conditioning circuit further includes a second voltage conditioning unit; The second voltage conditioning unit is electrically connected to the control circuit and is used to be electrically connected to the main circuit. It is used to output the second circuit voltage that conforms to the second voltage frequency in the circuit voltage to the control circuit for voltage protection.

5. The arc detection device according to claim 4, characterized in that, The second voltage conditioning unit includes a voltage divider resistor and a first inverting amplifier. The first end of the voltage divider resistor is electrically connected to the main circuit, the second end of the voltage divider resistor is electrically connected to the input terminal of the first inverting amplifier, and the output terminal of the first inverting amplifier is electrically connected to the control circuit.

6. The arc detection device according to claim 1, characterized in that, The arc current conditioning circuit includes an input unit and an arc current conditioning unit; The input unit is electrically connected to the arc transformer and is electrically connected to the control circuit through the arc current conditioning unit; The input unit is used to convert the arc current into an arc voltage and output it to the arc current conditioning unit; The arc current conditioning unit is used to condition the arc voltage and output the arc current conditioning voltage to the control circuit.

7. The arc detection device according to claim 6, characterized in that, The input unit includes a sampling resistor and a second non-inverting amplifier; The sampling resistor is electrically connected to the input terminals of the arc transformer and the second in-phase amplifier, respectively, and the output terminal of the second in-phase amplifier is electrically connected to the conditioning unit.

8. The arc detection device according to claim 6, characterized in that, The arc current conditioning unit includes a first conditioning subunit and a second conditioning subunit, and the arc current conditioning voltage includes a first current conditioning voltage and a second current conditioning voltage. The first conditioning subunit is electrically connected to the input unit and the control circuit, respectively, and is used to condition the portion of the arc voltage that conforms to the first current frequency and feed back the first current conditioning voltage for arc detection to the control circuit. The second conditioning subunit is electrically connected to the input unit and the control circuit, respectively, and is used to condition the portion of the arc voltage that conforms to the second current frequency and feed back the second current conditioning voltage for arc detection to the control circuit.

9. The arc detection device according to claim 8, characterized in that, The arc current conditioning unit further includes a third conditioning subunit, and the arc current conditioning voltage further includes a third current conditioning voltage; The third conditioning subunit is electrically connected to the input unit and the control circuit, respectively, and is used to condition the portion of the arc voltage that conforms to the third current frequency and feed back the third current conditioning voltage for current detection to the control circuit.

10. The arc detection device according to claim 9, characterized in that, The first conditioning subunit includes a second high-pass filter and a third non-inverting amplifier. The input terminal of the second high-pass filter is electrically connected to the input unit, the output terminal of the second high-pass filter is electrically connected to the input terminal of the third non-inverting amplifier, and the output terminal of the third non-inverting amplifier is electrically connected to the control circuit. And / or, the second conditioning subunit includes a first narrowband pass filter, a fourth inverting amplifier, a second narrowband pass filter, and a fifth inverting amplifier. The input terminal of the first narrowband pass filter is electrically connected to the input unit, the output terminal of the first narrowband pass filter is electrically connected to the input terminal of the fourth inverting amplifier, the output terminal of the fourth inverting amplifier is electrically connected to the input terminal of the second narrowband pass filter, the output terminal of the second narrowband pass filter is electrically connected to the input terminal of the fifth inverting amplifier, and the output terminal of the fifth inverting amplifier is electrically connected to the control circuit. And / or, the third conditioning subunit includes a first resistor, a second resistor, a capacitor, and a sixth non-inverting amplifier. The first end of the first resistor is electrically connected to the input unit. The second end of the first resistor is electrically connected to the first end of the second resistor and is electrically connected to the output end of the sixth non-inverting amplifier through the capacitor. The second end of the second resistor is electrically connected to the input end of the sixth non-inverting amplifier. The output end of the sixth non-inverting amplifier is also electrically connected to the control circuit.

11. An electrical protection system, characterized in that, Includes switching devices, driving circuits, and the arc detection device according to any one of claims 1 to 10; The switching device is connected in series in the main circuit and electrically connected to the control circuit through the drive circuit, and is used to disconnect when an electric arc occurs in the main circuit based on the control of the control circuit.

12. The electrical protection system according to claim 11, characterized in that, The electrical protection system also includes a zero-sequence current transformer and a leakage current conditioning circuit; The zero-sequence current transformer is electrically connected to the control circuit through the leakage current conditioning circuit. The leakage current conditioning circuit is used to receive the leakage current of the main circuit collected by the zero-sequence current transformer and feed back the leakage current conditioning voltage for leakage protection to the control circuit.

13. The electrical protection system according to claim 12, characterized in that, The second inverting amplifier of the leakage current conditioning circuit; The input terminal of the second inverting amplifier is electrically connected to the zero-sequence current transformer, and the output terminal of the second inverting amplifier is electrically connected to the control circuit.

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