Wire break detection method and circuit

Abstract

The present application relates to the technical field of three-phase power supply system protection, and discloses a disconnection detection method and circuit. The disconnection detection circuit includes a first sampling module, a second sampling module and a voltage judgment module. The first sampling module is respectively connected to the R line, S line, T line and N line of the AC power supply, the second sampling module is respectively connected to the R line, S line, T line and PE line of the AC power supply, and the voltage judgment module is respectively connected to the first sampling module and the second sampling module; the first sampling module is used to collect the first group of voltages generated when the AC power supply is input; the second sampling module is used to collect the second group of voltages generated when the AC power supply is input; the voltage judgment module is used to respectively obtain the first group of voltages collected by the first sampling module and the second group of voltages collected by the second sampling module, and determine the disconnection results of the N line and the disconnection results of the PE line according to the first group of voltages and the second group of voltages. The present application can accurately detect the disconnection of the N line and the PE line, reducing safety risks.

Description

Technical Field

[0001] The present application belongs to the technical field of three-phase power supply system protection, and in particular, relates to a line break detection method and circuit. Background Art

[0002] In the three-phase power supply system, the TN-S power supply system is widely used, which includes three phase lines (R line, S line, T line), a neutral line (N line) and a protective ground line (PE line). The N line and the PE line must be insulated after being separated at the neutral point of the power supply end, and no electrical connection is allowed. When the load impedance connected to the three phase lines is balanced, the neutral line potential is zero. However, in practical applications, the three-phase load is usually not completely balanced, and the N line is particularly important. If the N line is broken, the voltage of each phase on the load side will be too high or too low than the normal voltage, which may cause the electrical equipment to burn out or fail to work properly. If the PE line is broken, the exposed conductor of the equipment may be energized and endanger personal safety. Summary of the invention

[0003] The embodiments of the present application provide a line break detection method and circuit, which can detect in real time whether the N line and PE line in a three-phase power supply system are broken, thereby reducing safety risks.

[0004] In a first aspect, an embodiment of the present application provides a line break detection circuit, which includes a first sampling module, a second sampling module and a voltage judgment module, the first sampling module is respectively connected to the R line, S line, T line and N line of the AC power supply, the second sampling module is respectively connected to the R line, S line, T line and PE line of the AC power supply, and the voltage judgment module is respectively connected to the first sampling module and the second sampling module; the first sampling module is used to collect a first group of voltages generated when the AC power supply is input; the second sampling module is used to collect a second group of voltages generated when the AC power supply is input; the voltage judgment module is used to obtain the first group of voltages and the second group of voltages, respectively, and determine the line break results of the N line and the PE line according to the first group of voltages and the second group of voltages.

[0005] In some embodiments, the first sampling module and the second sampling module are respectively provided with three groups of impedances, wherein the three groups of impedances of the first sampling module are connected between the phase line and the N line, and the three groups of impedances of the second sampling module are connected between the phase line and the PE line; wherein the impedance values ​​of two groups of impedances among the three groups of impedances of the first sampling module are equal, and the impedance value of another group of impedances among the three groups of impedances of the first sampling module is greater than the impedance values ​​of the remaining two groups of impedances; the impedance values ​​of two groups of impedances among the three groups of impedances of the second sampling module are equal, and the impedance value of another group of impedances among the three groups of impedances of the second sampling module is greater than the impedance values ​​of the remaining two groups of impedances; and the larger value of the three groups of impedances of the first sampling module and the larger value of the three groups of impedances of the second sampling module are connected to different phases.

[0006] In some embodiments, each of the three groups of impedances of the first sampling module and the three groups of impedances of the second sampling module includes at least one of capacitance, resistance, and inductance.

[0007] In some embodiments, the line break detection circuit also includes a first group of terminals; the voltage judgment module is connected to the phase line through the first group of terminals; the voltage judgment module is also used to obtain a third group of voltages through the first group of terminals, and determine the line break result of the PE line based on the first group of voltages and the second group of voltages, and determine the line break result of the N line based on the first group of voltages and the third group of voltages.

[0008] In a second aspect, an embodiment of the present application provides a line break detection method, which is applied to the line break detection circuit as described above, wherein the line break detection circuit includes a first sampling module, a second sampling module and a voltage judgment module, wherein the first sampling module is respectively connected to the R line, S line, T line and N line of the AC power supply, the second sampling module is respectively connected to the R line, S line, T line and PE line of the AC power supply, and the voltage judgment module is respectively connected to the first sampling module and the second sampling module; the line break detection method includes: respectively acquiring a first group of voltages collected by the first sampling module and a second group of voltages collected by the second sampling module; and determining the line break results of the N line and the PE line according to the first group of voltages and the second group of voltages.

[0009] In some embodiments, the first group of voltages includes an N-line sampling voltage, the second group of voltages includes a PE-line sampling voltage, and determining the N-line disconnection result and the PE-line disconnection result based on the first group of voltages and the second group of voltages includes: calculating a first voltage to be measured based on the N-line sampling voltage and the PE-line sampling voltage; and determining the N-line disconnection result and the PE-line disconnection result based on the first voltage to be measured.

[0010] In some embodiments, determining the disconnection result of the N line and the disconnection result of the PE line based on the first voltage to be measured includes: if the first voltage to be measured is in a first interval, determining that the N line is not disconnected and the PE line is not disconnected; if the first voltage to be measured is in a second interval, determining that the N line is disconnected and the PE line is disconnected; if the first voltage to be measured is in a third interval, determining that the N line is disconnected and the PE line is not disconnected; if the first voltage to be measured is in a fourth interval, determining that the N line is not disconnected and the PE line is not disconnected.

[0011] In some embodiments, the line break detection method further includes: acquiring a third group of voltages; determining the line break result of the PE line according to the first group of voltages and the second group of voltages, and determining the line break result of the N line according to the first group of voltages and the third group of voltages.

[0012] In some embodiments, the first group of voltages includes an N-line sampling voltage, the second group of voltages includes a PE-line sampling voltage, and the third group of voltages includes an R-line sampling voltage, an S-line sampling voltage, and a T-line sampling voltage; determining the disconnection result of the PE line according to the first group of voltages and the second group of voltages, and determining the disconnection result of the N line according to the first group of voltages and the third group of voltages includes: calculating a first voltage to be measured according to the N-line sampling voltage and the PE-line sampling voltage; calculating a second voltage to be measured according to the R-line sampling voltage, the S-line sampling voltage, the T-line sampling voltage, and the N-line sampling voltage; determining the disconnection result of the PE line according to the first voltage to be measured; and determining the disconnection result of the N line according to the second voltage to be measured.

[0013] In some embodiments, the calculation of the second voltage to be measured based on the R line sampling voltage, the S line sampling voltage, the T line sampling voltage and the N line sampling voltage includes: calculating a first difference between the R line sampling voltage and the N line sampling voltage; calculating a second difference between the S line sampling voltage and the N line sampling voltage; calculating a third difference between the T line sampling voltage and the N line sampling voltage; and adding the first difference, the second difference and the third difference to obtain the second voltage to be measured.

[0014] In some embodiments, determining the disconnection result of the N line according to the second measured voltage includes: if the second measured voltage is in the fifth interval, determining that the N line is not disconnected; if the second measured voltage is in the sixth interval, determining that the N line is disconnected.

[0015] In some embodiments, determining the disconnection result of the PE line based on the first measured voltage includes: if the first measured voltage is in the first interval or the third interval, determining that the PE line is not disconnected; if the first measured voltage is in the second interval or the fourth interval, determining that the PE line is disconnected.

[0016] The embodiment of the present application provides a disconnection detection method and circuit, and the disconnection detection circuit includes a first sampling module, a second sampling module and a voltage judgment module. The first sampling module generates a first group of voltages between the N line and the R line, the S line, and the T line, and the second sampling module generates a second group of voltages between the PE line and the R line, the S line, and the T line. Then, the first group of voltages and the second group of voltages are calculated and judged to obtain the disconnection results of the N line and the disconnection results of the PE line. The disconnection detection method and circuit provided in the embodiment of the present application can more accurately detect the disconnection situation by simultaneously collecting the voltages of multiple lines and making a comprehensive judgment. By quickly discovering the disconnection problem of the N line and the PE line, timely measures can be taken to avoid safety hazards or other adverse effects caused by the disconnection. In addition, the circuit of the embodiment of the present application is used to detect whether the N line and the PE line are disconnected, and there is no need to connect additional components to the phase line of the AC power supply, which has less interference to the three-phase AC power, does not need to introduce complex algorithms, and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0018] Figure 1 is a structural block diagram of a disconnection detection circuit provided in an embodiment of the present application;

[0019] Figure 2 1 is a circuit structure diagram of a disconnection detection circuit provided in an embodiment of the present application;

[0020] Figure 3 It is a schematic diagram of the circuit structure of three groups of impedances of the first sampling module and one group of impedances among the three groups of impedances of the second sampling module provided in one embodiment of the present application;

[0021] Figure 4 This is a circuit structure diagram of a first sampling module and a second sampling module provided by an embodiment of the present application when both the N line and the PE line are disconnected;

[0022] Figure 5 It is a circuit structure diagram of a first sampling module and a second sampling module provided by an embodiment of the present application when both the N line and the PE line are disconnected;

[0023] Figure 6 This is a schematic diagram of the circuit structure of the first sampling module and the second sampling module when the N line is disconnected and the PE line is not disconnected, provided by an embodiment of the present application;

[0024] Figure 7 It is a circuit structure diagram of the first sampling module and the second sampling module provided by an embodiment of the present application when the N line is not disconnected and the PE line is disconnected;

[0025] Figure 8 is a circuit structure diagram of a disconnection detection circuit provided in another embodiment of the present application;

[0026] Fig. 9 This is a circuit structure diagram of the first sampling module and the second sampling module when both the N line and the PE line are disconnected, provided by another embodiment of the present application;

[0027] Fig.10 It is a circuit structure diagram of a first sampling module and a second sampling module provided by another embodiment of the present application when both the N line and the PE line are disconnected;

[0028] Fig.11 This is a circuit structure diagram of the first sampling module and the second sampling module when the N line is disconnected and the PE line is not disconnected, provided by another embodiment of the present application;

[0029] Fig.12 It is a circuit structure diagram of the first sampling module and the second sampling module when the N line is not disconnected and the PE line is disconnected, provided by another embodiment of the present application;

[0030] Fig.13 is a circuit structure diagram of a disconnection detection circuit provided in another embodiment of the present application;

[0031] Fig.14 It is a flowchart of a disconnection detection method provided by an embodiment of the present application;

[0032] Fig.15 It is a flowchart of a method for determining the disconnection result of the N line and the disconnection result of the PE line according to the first group of voltages and the second group of voltages in step S2 provided in an embodiment of the present application;

[0033] Fig.16 It is a flowchart of a method for determining the disconnection result of the N line and the disconnection result of the PE line according to the first voltage to be measured in step S22 provided in an embodiment of the present application;

[0034] Fig.17 is a flow chart of a disconnection detection method provided by another embodiment of the present application;

[0035] Fig.18It is a flowchart of a method for determining a disconnection result of a PE line according to a first group of voltages and a second group of voltages, and determining a disconnection result of an N line according to the first group of voltages and a third group of voltages, provided in step S6 of an embodiment of the present application;

[0036] Fig.19 It is a flowchart of a method for calculating a second voltage to be measured according to the R line sampling voltage, the S line sampling voltage, the T line sampling voltage and the N line sampling voltage in step S62 provided in an embodiment of the present application;

[0037] Fig. 20 It is a flowchart of a method for determining a disconnection result of a PE line according to a first voltage to be measured in step S63 provided in an embodiment of the present application;

[0038] Fig.21 It is a flowchart of a method for determining a disconnection result of the N line according to the second voltage to be measured in step S64 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and in detail in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0040] The technical features involved in the various embodiments of the present application described below do not conflict with each other and can be combined with each other.

[0041] Although the device schematic diagram is divided into functional modules and the flowchart shows a logical sequence, in some cases, the steps may be divided differently from the modules in the device or may be executed in an order different from that shown in the flowchart.

[0042] When an element is referred to as being “connected to” another element, it can be directly connected to the other element, or one or more intervening elements may be present therebetween.

[0043] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more.

[0044] See also Figure 1 , Figure 1 1 is a structural block diagram of a disconnection detection circuit 100 provided in an embodiment of the present application.

[0045] The embodiment of the present application provides a disconnection detection circuit 100 , which includes a first sampling module 10 , a second sampling module 20 and a voltage determination module 30 .

[0046] Specifically, the first sampling module 10 is connected to the R line, S line, T line and N line of the AC power supply respectively, the second sampling module 20 is connected to the R line, S line, T line and PE line of the AC power supply respectively, and the voltage judgment module 30 is connected to the first sampling module 10 and the second sampling module 20 respectively.

[0047] Among them, the first sampling module 10 is used to collect the first group of voltages generated when the AC power is input. The second sampling module 20 is used to collect the second group of voltages generated when the AC power is input. The voltage judgment module 30 is used to respectively obtain the first group of voltages collected by the first sampling module 10 and the second group of voltages collected by the second sampling module 20, and determine the disconnection result of the N line and the disconnection result of the PE line according to the first group of voltages and the second group of voltages. The disconnection result of the N line includes the disconnection of the N line and the disconnection of the N line, and the disconnection result of the PE line includes the disconnection of the PE line and the disconnection of the PE line.

[0048] Among them, the AC power supply is the TN-S system, which is a three-phase five-wire power supply system. In the TN-S system, the PE line and the N line are separated. The PE line can be repeatedly grounded, but the N line is not allowed to be repeatedly grounded. The three-phase five-wire system includes three phase lines R, S, and T, a working neutral line N, and a protective neutral line PE. The working neutral line N, together with the phase line, serves as a 220V power supply line. The protective neutral line PE is only used as a protective line to prevent electric shock.

[0049] In the embodiment of the present application, since the parameters of the components in the first sampling module 10 and the second sampling module 20 in the disconnection detection circuit 100 are known, and the values ​​of the first group of voltages and the second group of voltages are related to the parameters of the components in the first sampling module 10, the parameters of the components in the second sampling module 20, and whether the N line is disconnected and whether the PE line is disconnected. Therefore, the disconnection result of the N line and the disconnection result of the PE line can be determined by calculating and judging the first group of voltages and the second group of voltages.

[0050] See also Figure 2 , Figure 2 1 is a schematic diagram of a circuit structure of a disconnection detection circuit 100 provided in an embodiment of the present application.

[0051] In some embodiments, the first sampling module 10 and the second sampling module 20 are respectively provided with three groups of impedances. Figure 2As shown, the three groups of impedances of the first sampling module 10 include impedance Ztn, impedance Zsn, and impedance Zrn. The three groups of impedances of the second sampling module 20 include impedance Ztp, impedance Zsp, and impedance Zrp. Among them, the three groups of impedances of the first sampling module 10 are connected between the phase line and the N line, and the three groups of impedances of the second sampling module 20 are connected between the phase line and the PE line. Among them, the impedance values ​​of two groups of impedances in the three groups of impedances of the first sampling module 10 are equal, and the impedance value of another group of impedances in the three groups of impedances of the first sampling module 10 is greater than the impedance values ​​of the remaining two groups of impedances. The impedance values ​​of two groups of impedances in the three groups of impedances of the second sampling module 20 are equal, and the impedance value of another group of impedances in the three groups of impedances of the second sampling module 20 is greater than the impedance values ​​of the remaining two groups of impedances. In addition, the larger value of the three groups of impedances of the first sampling module 10 and the larger value of the three groups of impedances of the second sampling module 20 are connected to different phases.

[0052] For example, assuming that among the three impedance groups of the first sampling module 10, the impedance value of the impedance Ztn is Ztn, the impedance value of the impedance Zsn is Zsn, and the impedance value of the impedance Zrn is Zrn; then it is set that Ztn>Zsn=Zrn, or Zsn>Ztn=Zrn, or Zrn>Ztn=Zsn.

[0053] Assume that among the three impedance groups of the second sampling module 20, the impedance value of the impedance Ztp is Ztp, the impedance value of the impedance Zsp is Zsp, and the impedance value of the impedance Zrp is Zrp; then set Ztp>Zsp=Zrp, or Zsp>Ztp=Zrp, or Zrp>Ztp=Zrp.

[0054] Furthermore, the larger value of the three groups of impedances of the first sampling module 10 and the larger value of the three groups of impedances of the second sampling module 20 are connected to different phases. That is, if Ztn>Zsn=Zrn, then Zsp>Ztp=Zrp, or Zrp>Ztp=Zrp; if Zsn>Ztn=Zrn, then Ztp>Zsp=Zrp, or Zrp>Ztp=Zrp; if Zrn>Ztn=Zsn, then Ztp>Zsp=Zrp, or Zrp>Ztp=Zrp.

[0055] In some embodiments, each of the three groups of impedances of the first sampling module 10 and the three groups of impedances of the second sampling module 20 includes at least one of capacitance, resistance, and inductance.

[0056] See also Figure 3 , Figure 3 It is a circuit structure diagram of three groups of impedances of a first sampling module and one group of impedances among the three groups of impedances of a second sampling module provided in an embodiment of the present application.

[0057] like Figure 3As shown, one of the three groups of impedances of the first sampling module 10 and the three groups of impedances of the second sampling module 20 includes six cases, the first case is composed of a capacitor C, the second case is composed of a resistor R, the third case is composed of an inductor L, the fourth case is composed of a capacitor C and a resistor R in parallel, the fifth case is composed of an inductor L and a capacitor C in parallel, and the sixth case is composed of a resistor R and an inductor L in parallel.

[0058] It should be noted that, in an actual circuit, the three groups of impedances of the first sampling module 10 and the three groups of impedances of the second sampling module 20 may be composed of capacitors, resistors, inductors, or a combination of different components in series or in parallel, including but not limited to: Figure 3 The connection methods shown and the connection methods selected by technicians in the technical field to which this application belongs according to actual circuit requirements are all within the protection scope of this application.

[0059] In the embodiment of the present application, during detection, the connection between the first sampling module 10 and the second sampling module 20 in the disconnection detection circuit 100 may have the following four operating conditions.

[0060] The first working condition is that both the N line and the PE line are disconnected. Figure 4 As shown, at this time, one end of the impedance Zrn in the first sampling module 10 is connected to the R line, one end of the impedance Zsn is connected to the S line, one end of the impedance Ztn is connected to the T line, and the other end of the impedance Zrn, the other end of the impedance Zsn, and the other end of the impedance Ztn are all connected to the N line. One end of the impedance Zrp in the second sampling module 20 is connected to the R line, one end of the impedance Zsp is connected to the S line, one end of the impedance Ztp is connected to the T line, and the other end of the impedance Zrp, the other end of the impedance Zsp, and the other end of the impedance Ztp are all connected to the PE line.

[0061] The second working condition is that both the N line and the PE line are broken. Figure 5 As shown, at this time, one end of the impedance Zrn in the first sampling module 10 is connected to the R line, one end of the impedance Zsn is connected to the S line, one end of the impedance Ztn is connected to the T line, and the other end of the impedance Zrn, the other end of the impedance Zsn, and the other end of the impedance Ztn are connected to one point. One end of the impedance Zrp in the second sampling module 20 is connected to the R line, one end of the impedance Zsp is connected to the S line, one end of the impedance Ztp is connected to the T line, and the other end of the impedance Zrp, the other end of the impedance Zsp, and the other end of the impedance Ztp are connected to one point.

[0062] The third working condition is that the N line is broken and the PE line is not broken. Figure 6As shown, at this time, one end of the impedance Zrn in the first sampling module 10 is connected to the R line, one end of the impedance Zsn is connected to the S line, one end of the impedance Ztn is connected to the T line, and the other end of the impedance Zrn, the other end of the impedance Zsn, and the other end of the impedance Ztn are connected to one point. One end of the impedance Zrp in the second sampling module 20 is connected to the R line, one end of the impedance Zsp is connected to the S line, one end of the impedance Ztp is connected to the T line, and the other end of the impedance Zrp, the other end of the impedance Zsp, and the other end of the impedance Ztp are all connected to the PE line.

[0063] The fourth working condition is that the N line is not disconnected and the PE line is disconnected. Figure 7 As shown, at this time, one end of the impedance Zrn in the first sampling module 10 is connected to the R line, one end of the impedance Zsn is connected to the S line, one end of the impedance Ztn is connected to the T line, and the other end of the impedance Zrn, the other end of the impedance Zsn, and the other end of the impedance Ztn are all connected to the N line. One end of the impedance Zrp in the second sampling module 20 is connected to the R line, one end of the impedance Zsp is connected to the S line, one end of the impedance Ztp is connected to the T line, and the other end of the impedance Zrp, the other end of the impedance Zsp, and the other end of the impedance Ztp are connected to one point.

[0064] See also Figure 8 , Figure 8 1 is a schematic diagram of a circuit structure of a disconnection detection circuit 100 provided in an embodiment of the present application.

[0065] In some embodiments, the first voltage group includes N line sampling voltages, and the second voltage group includes PE line sampling voltages. The three impedance groups of the first sampling module 10 are three-phase capacitors, and the three impedance groups of the second sampling module 20 are three-phase capacitors.

[0066] The three-phase capacitor of the first sampling module 10 is connected between the phase line and the N line, and the three-phase capacitor of the second sampling module 20 is connected between the phase line and the PE line. The phase line refers to at least one of the three phase lines of the R line, the S line, and the T line.

[0067] Among them, the capacitance values ​​of two phase capacitors of the three-phase capacitors of the first sampling module 10 are equal, and the capacitance value of another phase capacitor of the three-phase capacitors of the first sampling module 10 is greater than the capacitance values ​​of the remaining two phase capacitors. The capacitance values ​​of two phase capacitors of the three-phase capacitors of the second sampling module 20 are equal, and the capacitance value of another phase capacitor of the three-phase capacitors of the second sampling module 20 is greater than the capacitance values ​​of the remaining two phase capacitors.

[0068] Furthermore, the larger value of the three-phase capacitor of the first sampling module 10 and the three-phase capacitor of the second sampling module 20 is connected to different phases.

[0069] In some embodiments, the three-phase capacitor of the first sampling module 10 includes a capacitor Crn, a capacitor Csn, and a capacitor Ctn, wherein the impedance Zrn is the capacitor Crn, the impedance Zsn is the capacitor Csn, and the impedance Ztn is the capacitor Ctn.

[0070] Specifically, the first end of capacitor Crn is connected to the R line, the first end of capacitor Csn is connected to the S line, the first end of capacitor Ctn is connected to the T line, the second end of capacitor Crn, the second end of capacitor Csn, and the second end of capacitor Ctn are all connected to the N line, and the second end of capacitor Crn, the second end of capacitor Csn, and the second end of capacitor Ctn are also connected to the voltage judgment module 30.

[0071] Among them, the capacitances of two of the capacitors Crn, Csn and Ctn are equal, and the capacitance of the other capacitor is greater than the capacitances of the two capacitors. That is, if the capacitance of the capacitor Crn is Crn, the capacitance of the capacitor Csn is Csn, and the capacitance of the capacitor Ctn is Ctn, then Crn>Csn=Ctn, or Csn>Crn=Ctn, or Ctn>Crn=Csn.

[0072] In some embodiments, the three-phase capacitor of the second sampling module 20 includes a capacitor Crp, a capacitor Csp, and a capacitor Ctp, wherein the impedance Zrp is the capacitor Crp, the impedance Zsp is the capacitor Csp, and the impedance Ztp is the capacitor Ctp.

[0073] Specifically, the first end of capacitor Crp is connected to the R line, the first end of capacitor Csp is connected to the S line, the first end of capacitor Ctp is connected to the T line, the second end of capacitor Crp, the second end of capacitor Csp, and the second end of capacitor Ctp are all connected to the PE line, and the second end of capacitor Crp, the second end of capacitor Csp, and the second end of capacitor Ctp are also connected to the voltage judgment module 30.

[0074] The capacitor in the first sampling module 10 is connected between the three phase lines and the N line to generate a first set of voltages. The capacitor in the second sampling module 20 is connected between the three phase lines and the N line to generate a second set of voltages.

[0075] Among them, the capacitances of two of the capacitance Crp, the capacitance Csp and the capacitance Ctp are equal, and the capacitance of the other capacitance is greater than the capacitances of the two capacitances. That is, if the capacitance of the capacitance Crp is Crp, the capacitance of the capacitance Csp is Csp, and the capacitance of the capacitance Ctp is Ctp, then Crp>Csp=Ctp, or Csp>Crp=Csp, or Ctp>Crp=Csp is set.

[0076] The capacitor with a larger capacitance in the first sampling module 10 and the capacitor with a larger capacitance in the second sampling module 20 are connected to different phase lines. That is, if Crn>Csn=Ctn, then Csp>Crp=Csp is set, or Ctp>Crp=Csp. If Csn>Crn=Ctn, then Crp>Csp=Ctp is set, or Ctp>Crp=Csp. If Ctn>Crn=Csn, then Crp>Csp=Ctp is set, or Csp>Crp=Csp. If Ctn>Crn=Csn, then Crp>Csp=Ctp is set, or Csp>Crp=Csp.

[0077] like Figure 8 As shown, the voltage judgment module 30 includes a voltage detection unit 31 and a main control chip 32 .

[0078] Specifically, the voltage detection unit 31 is connected to the first sampling module 10 , the second sampling module 20 and the main control chip 32 respectively.

[0079] The voltage detection unit 31 may include an analog-to-digital conversion device, a digital isolation device, etc., which is used to process the voltage signal and then output the signal to the main control chip 32. The main control chip 32 may be an MCU (Micro Control Unit) or other chips or devices that can implement the disconnection detection method of the present application.

[0080] The voltage detection unit 31 includes two terminals. One of the terminals is connected to the N line and the first sampling module 10 at one point to collect the N line sampling voltage. The other terminal is connected to the PE line and the second sampling module 20 at one point to collect the PE line sampling voltage. The main control chip 32 is burned with a program for determining the disconnection result of the N line and the disconnection result of the PE line according to the N line sampling voltage and the PE line sampling voltage.

[0081] In the embodiment of the present application, during detection, the connection between the first sampling module 10 and the second sampling module 20 in the disconnection detection circuit 100 may have the following four operating conditions.

[0082] The first working condition is that both the N line and the PE line are disconnected. Fig. 9 As shown, at this time, one end of the capacitor Crn in the first sampling module 10 is connected to the R line, one end of the capacitor Csn is connected to the S line, one end of the capacitor Ctn is connected to the T line, and the other end of the capacitor Crn, the other end of the capacitor Csn, and the other end of the capacitor Ctn are all connected to the N line. One end of the capacitor Crp in the second sampling module 20 is connected to the R line, one end of the capacitor Csp is connected to the S line, one end of the capacitor Ctp is connected to the T line, and the other end of the capacitor Crp, the other end of the capacitor Csp, and the other end of the capacitor Ctp are all connected to the PE line.

[0083] The second working condition is that both the N line and the PE line are broken. Fig.10As shown, at this time, one end of the capacitor Crn in the first sampling module 10 is connected to the R line, one end of the capacitor Csn is connected to the S line, one end of the capacitor Ctn is connected to the T line, and the other end of the capacitor Crn, the other end of the capacitor Csn, and the other end of the capacitor Ctn are connected to one point. One end of the capacitor Crp in the second sampling module 20 is connected to the R line, one end of the capacitor Csp is connected to the S line, one end of the capacitor Ctp is connected to the T line, and the other end of the capacitor Crp, the other end of the capacitor Csp, and the other end of the capacitor Ctp are connected to one point.

[0084] The third working condition is that the N line is broken and the PE line is not broken. Fig.11 As shown, at this time, one end of the capacitor Crn in the first sampling module 10 is connected to the R line, one end of the capacitor Csn is connected to the S line, one end of the capacitor Ctn is connected to the T line, and the other end of the capacitor Crn, the other end of the capacitor Csn, and the other end of the capacitor Ctn are connected to one point. One end of the capacitor Crp in the second sampling module 20 is connected to the R line, one end of the capacitor Csp is connected to the S line, one end of the capacitor Ctp is connected to the T line, and the other end of the capacitor Crp, the other end of the capacitor Csp, and the other end of the capacitor Ctp are all connected to the PE line.

[0085] The fourth working condition is that the N line is not disconnected and the PE line is disconnected. Fig.12 As shown, at this time, one end of the capacitor Crn in the first sampling module 10 is connected to the R line, one end of the capacitor Csn is connected to the S line, one end of the capacitor Ctn is connected to the T line, and the other end of the capacitor Crn, the other end of the capacitor Csn, and the other end of the capacitor Ctn are all connected to the N line. One end of the capacitor Crp in the second sampling module 20 is connected to the R line, one end of the capacitor Csp is connected to the S line, one end of the capacitor Ctp is connected to the T line, and the other end of the capacitor Crp, the other end of the capacitor Csp, and the other end of the capacitor Ctp are connected to one point.

[0086] See also Fig.13 , Fig.13 2 is a circuit structure diagram of a disconnection detection circuit 100 provided in another embodiment of the present application.

[0087] In some embodiments, Fig.13 As shown, the line break detection circuit 100 also includes a first group of terminals. The voltage judgment module 30 is connected to the phase line through the first group of terminals. Specifically, the voltage judgment module 30 is also used to obtain a third group of voltages through the first group of terminals, and determine the line break result of the PE line according to the first group of voltages and the second group of voltages, and determine the line break result of the N line according to the first group of voltages and the third group of voltages.

[0088] In some embodiments, the first group of voltages includes R line sampling voltages, the second group of voltages includes PE line sampling voltages, and the third group of voltages includes S line sampling voltages, T line sampling voltages, and N line sampling voltages.

[0089] Specifically, Fig.13 As shown, the first terminal is connected to the R line, the first sampling module 10, and the second sampling module 20 at one point to collect the R line sample voltage. The second terminal is connected to the S line, the first sampling module 10, and the second sampling module 20 at one point to collect the S line sample voltage. The third terminal is connected to the T line, the first sampling module 10, and the second sampling module 20 at one point to collect the T line sample voltage.

[0090] The method for determining the disconnection result of the PE line according to the first group of voltages and the second group of voltages, and the method for determining the disconnection result of the N line according to the first group of voltages and the third group of voltages may refer to the following disconnection detection method.

[0091] In this embodiment, the line break detection circuit 100 includes a first sampling module 10, a second sampling module 20 and a voltage judgment module 30. The first sampling module 10 generates a first group of voltages between the N line and the R line, the S line, and the T line, and the second sampling module 20 generates a second group of voltages between the PE line and the R line, the S line, and the T line. Then, the first group of voltages and the second group of voltages are calculated and judged to obtain the line break results of the N line and the line break results of the PE line. The embodiment of the present application can more accurately detect the line break by simultaneously collecting the voltages of multiple lines and making a comprehensive judgment. By quickly discovering the line break problems of the N line and the PE line, timely measures can be taken to avoid safety hazards or other adverse effects caused by the line break. In addition, the circuit of the embodiment of the present application is used to detect whether the N line and the PE line are broken, and there is no need to connect additional components to the phase line of the AC power supply, which has less interference with the three-phase AC power, does not require the introduction of complex algorithms, and has low cost.

[0092] See also Fig.14 , Fig.14 It is a flowchart of a disconnection detection method provided in an embodiment of the present application.

[0093] The embodiment of the present application also provides a disconnection detection method, which is applied to the disconnection detection circuit 100 as described above, and the disconnection detection circuit 100 includes a first sampling module 10, a second sampling module 20 and a voltage judgment module 30. The first sampling module 10 is respectively connected to the R line, S line, T line and N line of the AC power supply, the second sampling module 20 is respectively connected to the R line, S line, T line and PE line of the AC power supply, and the voltage judgment module 30 is respectively connected to the first sampling module 10 and the second sampling module 20. The disconnection detection method includes:

[0094] Step S1 : respectively acquiring a first group of voltages collected by the first sampling module 10 and a second group of voltages collected by the second sampling module 20 .

[0095] Specifically, through Figure 2 The disconnection detection circuit 100 shown in FIG. Figure 3 The wire break detection circuit 100 shown generates and collects a first set of voltages and a second set of voltages.

[0096] Step S2: determining a disconnection result of the N line and a disconnection result of the PE line according to the first group of voltages and the second group of voltages.

[0097] Specifically, since the parameters of the components in the first sampling module 10 and the second sampling module 20 in the disconnection detection circuit 100 are known, and the values ​​of the first group of voltages and the second group of voltages are related to the parameters of the components in the first sampling module 10, the parameters of the components in the second sampling module 20, and whether the N line is disconnected and whether the PE line is disconnected, the disconnection result of the N line and the disconnection result of the PE line can be determined by calculating and judging the first group of voltages and the second group of voltages.

[0098] See also Fig.15 , Fig.15 It is a flowchart of a method for determining the disconnection result of the N line and the disconnection result of the PE line according to the first group of voltages and the second group of voltages in step S2 provided in an embodiment of the present application.

[0099] In some embodiments, the first voltage group includes N line sampling voltages, and the second voltage group includes PE line sampling voltages. Figure 2 ,like Figure 2 As shown, the N line sampled voltage is the voltage collected by the voltage detection unit 31 through the terminal connected to the N line and the first sampling module 10. The PE line sampled voltage is the voltage collected by the terminal connected to the PE line and the second sampling module 20 by the voltage detection unit 31.

[0100] In some embodiments, step S2, determining the disconnection result of the N line and the disconnection result of the PE line according to the first group of voltages and the second group of voltages, includes:

[0101] Step S21, calculating a first voltage to be measured according to the N line sampled voltage and the PE line sampled voltage.

[0102] Specifically, the voltage between the N line sampling voltage and the PE line sampling voltage is calculated, which is the first voltage to be measured.

[0103] Step S22: determining the disconnection result of the N line and the disconnection result of the PE line according to the first voltage to be measured.

[0104] In some embodiments, the line break detection method also includes: calculating a first voltage, a second voltage, a third voltage, and a fourth voltage between the N line and the PE line under four operating conditions of the line break detection circuit; determining four intervals based on the first voltage, the second voltage, the third voltage, and the fourth voltage, the four intervals including a first interval, a second interval, a third interval, and a fourth interval.

[0105] Among them, the four working conditions of the disconnection detection circuit include the first working condition (the working condition in which both the N line and the PE line are not disconnected), the second working condition (the N line and the PE line are both disconnected), the third working condition (the N line is disconnected and the PE line is not disconnected), and the fourth working condition (the N line is not disconnected and the PE line is disconnected).

[0106] In this embodiment, it is assumed that the effective value of the three-phase output voltage of the AC power supply is Urms. Usually, the time domain expressions of the three-phase voltages of R, S, and T are respectively:

[0107] ;

[0108] ;

[0109] ;

[0110] It can be expressed by phasor method as:

[0111] ;

[0112] ;

[0113] ;

[0114] In the above formula, is the voltage of the R line of the AC power supply, is the voltage of the S line of the AC power supply, is the voltage of the T line of the AC power supply.

[0115] Next, the node voltages between the three groups of impedances in the first sampling module 10 and the N line (N line sampling voltage) and the node voltages between the three groups of impedances in the second sampling module 20 and the PE line (PE line sampling voltage) are calculated.

[0116] Specifically, the impedance Zrn, impedance Zsn, impedance Ztn and the node voltage phasor of the N line are: , the node voltage between impedance Zrp, impedance Zsp, impedance Ztp and PE line is ,according to Figure 2 And Kirchhoff's Current Law (KCL), we can get the following formula:

[0117] .

[0118] untie , we can get the following The formula is:

[0119] .

[0120] The same can be said The formula is:

[0121] .

[0122] In the above formula, is the voltage of the R line of the AC power supply, is the voltage of the S line of the AC power supply, is the voltage of the T line of the AC power supply, is the impedance of the impedance Zrn, is the impedance of the impedance Zsn, is the impedance of the impedance Ztn, is the impedance of the impedance Zrp, is the impedance of the impedance Zsp, is the impedance of the impedance Ztp.

[0123] Among them, Figure 2 As shown, if the N line is not disconnected, then If the PE line, then .

[0124] In this embodiment, the first voltage to be measured is the voltage phasor between the N line sampling voltage and the PE line sampling voltage. , that is .

[0125] Specifically, calculating the first voltage, the second voltage, the third voltage, and the fourth voltage between the N line and the PE line under four working conditions of the line break detection circuit includes:

[0126] In the first working condition, when both the N line and the PE line are disconnected, Figure 4 As shown, the first voltage is 0.

[0127] In the second working condition, when both the N line and the PE line are disconnected, Figure 5 As shown, the second voltage is calculated according to the following formula:

[0128] .

[0129] In the above formula, is the voltage of the R line of the AC power supply, is the voltage of the S line of the AC power supply, is the voltage of the T line of the AC power supply, is the impedance of the impedance Zrn, is the impedance of impedance Zsn, is the impedance of impedance Ztn, is the impedance of impedance Zrp, is the impedance of impedance Zsp, is the impedance of impedance Ztp.

[0130] Under the third working condition, that is, when the N line is broken and the PE line is not broken, as Figure 6 shown, calculate the third voltage according to the following formula:

[0131] .

[0132] Under the fourth working condition, that is, when the N line is not broken and the PE line is broken, as Figure 7 shown, calculate the fourth voltage according to the following formula:

[0133] .

[0134] Generally, the first voltage < the third voltage < the fourth voltage < the second voltage, or the first voltage < the fourth voltage < the third voltage < the second voltage.

[0135] Let the first voltage be A, the second voltage be B, the third voltage be C, and the fourth voltage be D.

[0136] Specifically, when the first voltage < the third voltage < the fourth voltage < the second voltage, that is, A < C < D < B, the method for determining the four intervals according to the first voltage, the second voltage, the third voltage, and the fourth voltage includes: determining the first interval as [A, C), the second interval as the interval ≥ B, the third interval as [C, D), and the fourth interval as [D, B). For details, please refer to Table 1 below:

[0137] Table 1

[0138]

[0139] Specifically, when the first voltage < the fourth voltage < the third voltage < the second voltage, that is, A < D < C < B, the method for determining the four intervals according to the first voltage, the second voltage, the third voltage, and the fourth voltage includes: determining the first interval as [A, D), the second interval as the interval ≥ B, the third interval as [C, B), and the fourth interval as [D, C). For details, please refer to Table 2 below:

[0140] Table 2

[0141]

[0142] Please refer to Fig.16 , Fig.16It is a flowchart of a method for determining the disconnection result of the N line and the disconnection result of the PE line according to the first voltage to be measured in step S22 provided in an embodiment of the present application.

[0143] In some embodiments, step S22, determining the disconnection result of the N line and the disconnection result of the PE line according to the first voltage to be measured, includes:

[0144] Step S221: If the first voltage to be measured is in the first interval, determine that the N line is not disconnected and the PE line is not disconnected.

[0145] Step S222: If the first voltage to be measured is in the second interval, it is determined that the N line is broken and the PE line is broken.

[0146] Step S223: If the first voltage to be measured is in the third interval, it is determined that the N line is disconnected and the PE line is not disconnected.

[0147] Step S224: If the first voltage to be measured is in the fourth interval, it is determined that the N line is not disconnected and the PE line is disconnected.

[0148] The following takes the first sampling module 10 where the impedance Zrn is the capacitor Crn, the impedance Zsn is the capacitor Csn, and the impedance Ztn is the capacitor Ctn; the second sampling module 20 where the impedance Zrp is the capacitor Crp, the impedance Zsp is the capacitor Csp, and the impedance Ztp is the capacitor Ctp as an example to describe the embodiment in detail.

[0149] It can be known that the impedance of a capacitor is:

[0150] .

[0151] Combined with the calculation formulas for the first voltage, the second voltage, the third voltage, and the fourth voltage in the above embodiments, we can obtain the calculation formula for the first voltage, the calculation formula for the second voltage, the calculation formula for the third voltage, and the calculation formula for the fourth voltage composed of capacitance Crn, capacitance Csn, capacitance Ctn, capacitance Crp, capacitance Csp, capacitance Ctp, and Urms.

[0152] Specifically, calculating the first voltage, the second voltage, the third voltage, and the fourth voltage between the N line and the PE line under four working conditions of the line break detection circuit includes:

[0153] In the first working condition, that is, when both the N line and the PE line are disconnected, Fig. 9 As shown, the first voltage is 0.

[0154] In the second working condition, when both the N line and the PE line are disconnected, Fig.10 As shown, the second voltage is calculated according to the following formula:

[0155] .

[0156] In the above formula, Urms is the effective value of the three-phase output voltage of the AC power supply, Crn is the capacitance value of capacitor Crn, Csn is the capacitance value of capacitor Csn, Ctn is the capacitance value of capacitor Ctn, Crp is the capacitance value of capacitor Crp, Csp is the capacitance value of capacitor Csp, and Ctp is the capacitance value of capacitor Ctp.

[0157] In the third working condition, when the N line is disconnected and the PE line is not disconnected, Fig.11 As shown, the third voltage is calculated according to the following formula:

[0158] .

[0159] In the fourth working condition, when the N line is not disconnected and the PE line is disconnected, Fig.12 As shown, the fourth voltage is calculated according to the following formula:

[0160] .

[0161] For example, if the capacitance of capacitor Csn and the capacitance of capacitor Ctn are both 1μF, the capacitance of capacitor Crn is 2.2μF, the capacitance of capacitor Crp and the capacitance of capacitor Csp are both 4.7nF, the capacitance of capacitor Ctp is 47nF, and the three-phase output voltage of the AC power supply is Urms. According to the above method, the first voltage can be calculated to be 0, the second voltage is 0.9265Urms, the third voltage is 0.2857Urms, and the fourth voltage is 0.75Urms. In addition, the first interval is determined to be [0, 0.2857Urms), the second interval is ≥0.9265Urms, the third interval is [0.2857Urms, 0.75Urms), and the fourth interval is [0.75Urms, 0.9265Urms). For details, please refer to the following Table 3:

[0162] Table 3

[0163]

[0164] According to the above calculation results, if the first voltage to be measured U1 is measured to be within 0≤U1<0.2857Urms, it is determined that both the N line and the PE line are connected.

[0165] If the first voltage to be measured U1 is measured to be within 0.2857Urms≤U1<0.75Urms, it is determined that the N line is broken and the PE line is not broken.

[0166] If the first voltage to be measured U1 is measured at 0.75Urms≤U1<0.9265Urms, it is determined that the N line is not disconnected and the PE line is disconnected.

[0167] If the first measured voltage U1 is measured to be ≥ 0.9265Urms, it is determined that both the N line and the PE line are broken.

[0168] See also Fig.17 , Fig.17 It is a flowchart of a disconnection detection method provided in another embodiment of the present application.

[0169] In some embodiments, the disconnection detection method further includes the following steps S5 and S6:

[0170] Step S5, obtaining a third set of voltages.

[0171] Step S6: determining the disconnection result of the PE line according to the first group of voltages and the second group of voltages, and determining the disconnection result of the N line according to the first group of voltages and the third group of voltages.

[0172] See also Fig.18 , Fig.18 It is a flowchart of a method for determining the disconnection result of the PE line according to the first group of voltages and the second group of voltages, and determining the disconnection result of the N line according to the first group of voltages and the third group of voltages provided in step S6 of an embodiment of the present application.

[0173] In some embodiments, the first group of voltages includes the N line sampling voltage, the second group of voltages includes the PE line sampling voltage, and the third group of voltages includes the R line sampling voltage, the S line sampling voltage, and the T line sampling voltage. Fig.13 ,like Fig.13 As shown, the N line sampling voltage is the voltage collected by the voltage judgment module 30 through the terminal connected to the N line and the first sampling module 10. The R line sampling voltage is the voltage collected by the voltage judgment module 30 through the terminal connected to the R line, the first sampling module 10, and the second sampling module 20. The S line sampling voltage is the voltage collected by the voltage judgment module 30 through the terminal connected to the S line, the first sampling module 10, and the second sampling module 20. The T line sampling voltage is the voltage collected by the voltage judgment module 30 through the terminal connected to the T line, the first sampling module 10, and the second sampling module 20. The PE line sampling voltage is the voltage collected by the voltage judgment module 30 through the terminal connected to the PE line and the second sampling module 20.

[0174] The above step S6, determining the disconnection result of the PE line according to the first group of voltages and the second group of voltages, and determining the disconnection result of the N line according to the first group of voltages and the third group of voltages, includes the following steps S61 to S64:

[0175] Step S61, calculating a first voltage to be measured according to the N line sampled voltage and the PE line sampled voltage.

[0176] Specifically, the voltage between the N line sampling voltage and the PE line sampling voltage is calculated, which is the first voltage to be measured.

[0177] Step S62, calculating a second voltage to be measured according to the R line sampling voltage, the S line sampling voltage, the T line sampling voltage and the N line sampling voltage.

[0178] Step S63: determining the disconnection result of the PE line according to the first voltage to be measured.

[0179] Step S64: determining the disconnection result of the N line according to the second voltage to be measured.

[0180] See also Fig.19 , Fig.19 It is a flowchart of a method for calculating a second voltage to be measured according to the R line sampling voltage, the S line sampling voltage, the T line sampling voltage and the N line sampling voltage, in step S62 provided in an embodiment of the present application.

[0181] In some embodiments, the above step S62, calculating the second voltage to be measured according to the R line sampling voltage, the S line sampling voltage, the T line sampling voltage and the N line sampling voltage, includes the following steps S621 to S624:

[0182] Step S621 : Calculate a first difference between the R line sampling voltage and the N line sampling voltage.

[0183] Step S622: Calculate a second difference between the S line sampling voltage and the N line sampling voltage.

[0184] Step S623: Calculate a third difference between the T-line sampling voltage and the N-line sampling voltage.

[0185] Step S624, adding the first difference, the second difference and the third difference to obtain a second voltage to be measured.

[0186] See also Fig. 20 , Fig. 20 It is a flowchart of a method for determining a disconnection result of a PE line according to a first voltage to be measured, in step S63, provided in an embodiment of the present application.

[0187] In some embodiments, the above step S63, determining the disconnection result of the PE line according to the first voltage to be measured, includes the following steps S631 and S632:

[0188] Step S631: If the first voltage to be measured is within the first interval or the third interval, it is determined that the PE line is not disconnected.

[0189] Step S632: If the first voltage to be measured is in the second interval or the fourth interval, it is determined that the PE line is broken.

[0190] In some embodiments, the line break detection method also includes: calculating a first voltage, a second voltage, a third voltage, and a fourth voltage between the N line and the PE line under four operating conditions of the line break detection circuit; determining four intervals based on the first voltage, the second voltage, the third voltage, and the fourth voltage, the four intervals including a first interval, a second interval, a third interval, and a fourth interval.

[0191] Regarding the determination of the first interval, the second interval, the third interval, and the fourth interval, reference may be made to the above-mentioned circuit embodiment, which will not be described in detail here.

[0192] See also Fig.21 , Fig.21 It is a flowchart of a method for determining a disconnection result of the N line according to the second voltage to be measured in step S64 provided in an embodiment of the present application.

[0193] In some embodiments, the above step S64, determining the disconnection result of the N line according to the second voltage to be measured, includes the following steps S641 and S642:

[0194] Step S641: if the second voltage to be measured is in the fifth interval, determine that the N line is not disconnected;

[0195] Step S642: If the second voltage to be measured is in the sixth interval, it is determined that the N line is broken.

[0196] In some embodiments, the line break detection method further includes: calculating a fifth voltage and a sixth voltage between the N line and the PE line under two operating conditions of the line break detection circuit; determining two intervals according to the fifth voltage and the sixth voltage, the two intervals including a fifth interval and a sixth interval.

[0197] The two working conditions of the disconnection detection circuit include the fifth working condition (the N line is not disconnected) and the sixth working condition (the N line is disconnected).

[0198] In some embodiments, the fifth voltage is set to E and the sixth voltage is set to F. Specifically, two intervals are determined according to the fifth voltage and the sixth voltage, and the two intervals include the fifth interval and the sixth interval. The fifth interval is determined to be [E, F), and the sixth interval is determined to be an interval ≥ F. For details, see Table 4 below:

[0199] Table 4

[0200]

[0201] Specific, structure Fig.13 , assuming the sum of the three-phase voltages is , substituting into the three-phase voltage phasor, we have the following formula:

[0202] .

[0203] In the above formula, is the R line sampling voltage, is the S line sampling voltage, is the T line sampling voltage, is the N-line sampling voltage).

[0204] Calculating the fifth voltage and the sixth voltage between the N line and the PE line under two working conditions of the line break detection circuit includes:

[0205] Under the fifth working condition, that is, when the N line is not disconnected, the calculation formula of the fifth voltage is:

[0206] .

[0207] In the second working condition, that is, when the N line is disconnected, the sixth voltage is calculated according to the following formula:

[0208] .

[0209] in, is the R line sampling voltage, is the S line sampling voltage, is the T line sampling voltage, is the N-line sampling voltage), is the impedance of the impedance Zrn, is the impedance of the impedance Zsn, is the impedance of the impedance Ztn, is the impedance of the impedance Zrp, is the impedance of the impedance Zsp, is the impedance of the impedance Ztp.

[0210] Specifically, the fifth interval is ; The sixth interval is . Wherein, U1 is the sixth voltage mentioned above.

[0211] The embodiment of the present application provides a disconnection detection method, which is applied to the disconnection detection circuit described above, and can more accurately detect disconnection by simultaneously collecting the voltages of multiple lines and making a comprehensive judgment. By quickly discovering the disconnection problem of the N line and the PE line, timely measures can be taken to avoid safety hazards or other adverse effects caused by disconnection.

[0212] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0213] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0214] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A disconnection detection circuit, characterized in that: The disconnection detection circuit includes a first sampling module, a second sampling module and a voltage judgment module; The voltage judgment module is connected to the first sampling module and the second sampling module respectively, and the first sampling module and the second sampling module are respectively provided with three groups of impedances, wherein one end of the three groups of impedances of the first sampling module are respectively connected to the R line, the S line, and the T line of the AC power supply, and the other end of the three groups of impedances of the first sampling module are all connected to the N line of the AC power supply, one end of the three groups of impedances of the second sampling module are respectively connected to the R line, the S line, and the T line of the AC power supply, and the other end of the three groups of impedances of the second sampling module are all connected to the PE line of the AC power supply; The first sampling module is used to collect a first group of voltages generated when the AC power supply is input; the first group of voltages includes an N-line sampling voltage, and the N-line sampling voltage is a node voltage between three groups of impedances of the first sampling module and the N-line; The second sampling module is used to collect a second group of voltages generated when the AC power supply is input; the second group of voltages includes a PE line sampling voltage, and the PE line sampling voltage is a node voltage between three groups of impedances of the second sampling module and the PE line; The voltage judgment module is used to obtain the first group of voltages and the second group of voltages respectively, and determine the disconnection results of the N line and the PE line according to the voltage phasors of the first group of voltages and the voltage phasors of the second group of voltages.

2. The disconnection detection circuit according to claim 1, characterized in that: The impedance values ​​of two groups of impedances among the three groups of impedances of the first sampling module are equal, and the impedance value of another group of impedances among the three groups of impedances of the first sampling module is greater than the impedance values ​​of the remaining two groups of impedances; the impedance values ​​of two groups of impedances among the three groups of impedances of the second sampling module are equal, and the impedance value of another group of impedances among the three groups of impedances of the second sampling module is greater than the impedance values ​​of the remaining two groups of impedances; Furthermore, a larger value among the three groups of impedances of the first sampling module and a larger value among the three groups of impedances of the second sampling module are connected to different phases.

3. The disconnection detection circuit according to claim 2, characterized in that: Each of the three groups of impedances of the first sampling module and the three groups of impedances of the second sampling module includes at least one of capacitance, resistance and inductance.

4. The disconnection detection circuit according to claim 2 or 3, characterized in that: The disconnection detection circuit also includes a first set of terminals; The voltage judgment module is connected to the phase line through the first group of terminals; The voltage judgment module is further used to obtain a third group of voltages through the first group of terminals, and determine the disconnection result of the PE line according to the difference between the voltage phasor of the first group of voltages and the voltage phasor of the second group of voltages, and determine the disconnection result of the N line according to multiple differences calculated from the first group of voltages and the third group of voltages; Wherein, the third group of voltages includes an R line sampling voltage, an S line sampling voltage, and a T line sampling voltage; the above steps include: taking the difference between the voltage phasor of the N line sampling voltage and the voltage phasor of the PE line sampling voltage as the first voltage to be measured; calculating the second voltage to be measured according to multiple differences calculated from the R line sampling voltage, the S line sampling voltage, the T line sampling voltage, and the N line sampling voltage; determining the disconnection result of the PE line according to the first voltage to be measured; determining the disconnection result of the N line according to the second voltage to be measured; Among them, the calculation of the second voltage to be measured based on the multiple differences calculated according to the R line sampling voltage, the S line sampling voltage, the T line sampling voltage and the N line sampling voltage includes: calculating the first difference between the R line sampling voltage and the N line sampling voltage; calculating the second difference between the S line sampling voltage and the N line sampling voltage; calculating the third difference between the T line sampling voltage and the N line sampling voltage; adding the first difference, the second difference and the third difference to obtain the second voltage to be measured.

5. A disconnection detection method, characterized in that: Applied to the disconnection detection circuit according to any one of claims 2 to 4, the disconnection detection method comprises: Acquire a first group of voltages collected by a first sampling module and a second group of voltages collected by a second sampling module respectively; the first group of voltages includes an N-line sampling voltage, which is a node voltage between three groups of impedances of the first sampling module and the N-line; the second group of voltages includes a PE-line sampling voltage, which is a node voltage between three groups of impedances of the second sampling module and the PE-line; A disconnection result of the N line and a disconnection result of the PE line are determined according to the voltage phasors of the first group of voltages and the voltage phasors of the second group of voltages.

6. The disconnection detection method according to claim 5, characterized in that: The determining the disconnection result of the N line and the disconnection result of the PE line according to the voltage phasor of the first group of voltages and the voltage phasor of the second group of voltages comprises: Calculating a first voltage to be measured according to a difference between a voltage phasor of the N-line sampled voltage and a voltage phasor of the PE-line sampled voltage; A disconnection result of the N line and a disconnection result of the PE line are determined according to the first voltage to be measured.

7. The disconnection detection method according to claim 6, characterized in that: The determining the disconnection result of the N line and the disconnection result of the PE line according to the first voltage to be measured includes: If the first voltage to be measured is in the first interval, determining that the N line is not disconnected and the PE line is not disconnected; If the first voltage to be measured is in the second interval, it is determined that the N line is broken and the PE line is broken; If the first voltage to be measured is in the third interval, it is determined that the N line is disconnected and the PE line is not disconnected; If the first voltage to be measured is in the fourth interval, it is determined that the N line is not disconnected and the PE line is disconnected.

8. The disconnection detection method according to claim 5, characterized in that: The disconnection detection method further comprises: Get the third set of voltages; Determine the disconnection result of the PE line according to the difference between the voltage phasor of the first group of voltages and the voltage phasor of the second group of voltages, and determine the disconnection result of the N line according to a plurality of differences calculated from the first group of voltages and the third group of voltages; Wherein, the third group of voltages includes an R line sampling voltage, an S line sampling voltage, and a T line sampling voltage; the above steps include: taking the difference between the voltage phasor of the N line sampling voltage and the voltage phasor of the PE line sampling voltage as the first voltage to be measured; calculating the second voltage to be measured according to multiple differences calculated from the R line sampling voltage, the S line sampling voltage, the T line sampling voltage, and the N line sampling voltage; determining the disconnection result of the PE line according to the first voltage to be measured; determining the disconnection result of the N line according to the second voltage to be measured; Among them, the calculation of the second voltage to be measured based on the multiple differences calculated according to the R line sampling voltage, the S line sampling voltage, the T line sampling voltage and the N line sampling voltage includes: calculating the first difference between the R line sampling voltage and the N line sampling voltage; calculating the second difference between the S line sampling voltage and the N line sampling voltage; calculating the third difference between the T line sampling voltage and the N line sampling voltage; adding the first difference, the second difference and the third difference to obtain the second voltage to be measured.

9. The disconnection detection method according to claim 8, characterized in that: The determining the disconnection result of the N line according to the second voltage to be measured comprises: If the second voltage to be measured is in the fifth interval, determining that the N line is not disconnected; If the second voltage to be measured is in the sixth interval, it is determined that the N line is broken.

10. The disconnection detection method according to claim 8, characterized in that: The determining the disconnection result of the PE line according to the first voltage to be measured includes: If the first voltage to be measured is within the first interval or the third interval, determining that the PE line is not disconnected; If the first voltage to be measured is in the second interval or the fourth interval, it is determined that the PE line is broken.

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