Insulation monitoring circuit and insulation monitoring device

Abstract

The utility model belongs to the technical field of electrician and electronics, and relates to an insulation monitoring circuit and an insulation monitoring device. The energy storage capacitor is electrically connected with the relay group, and the relay group is switched to be electrically connected with the charging circuit, the measuring circuit or the indicating circuit after being started; the indicating circuit comprises a comparison circuit, an indicating module and an indicating reference unit. The relay group is configured as follows: the energy storage capacitor is connected to the positive electrode and the negative electrode of the system power supply; or the energy storage capacitor is connected to the positive electrode and the grounding end of the system power supply; or, the comparison circuit compares the energy storage capacitor with the indication reference unit, and indicates the insulation condition through the indication module; according to the utility model, the energy storage capacitor is used as an energy storage element, a qualitative indication function is realized by using the comparison circuit, and meanwhile, the measurement circuit is isolated from the system circuit, so that the monitoring requirement of a user is met with lower cost.

Description

Technical Field

[0001] This utility model belongs to the field of electrical and electronic technology, specifically relating to insulation monitoring circuits and insulation monitoring devices. Background Technology

[0002] If it is necessary to test the insulation between the power supply system V+ / V- and the casing GND, the insulation testing equipment will generate a low-frequency pulse signal on the casing GND relative to its power supply Vo-, and measure whether there is a corresponding pulse signal on the V+ (or V-) line relative to its power supply Vo-, as well as the magnitude of the pulse signal, so as to determine whether GND and V+ are connected, and the magnitude of the connection resistance, thereby determining its insulation performance.

[0003] In the above technologies, in order to avoid interference from the measuring circuit to the circuit under test, it is necessary to maintain isolation between the detected system V+ / V- and the signal system Vo+ / Vo- used for detection. This often requires the use of isolated power supply technology, which is somewhat complex and costly. However, in most cases, users are more concerned with qualitative insulation performance, so a simple insulation monitoring circuit or device is needed to achieve this goal. Utility Model Content

[0004] To overcome the shortcomings of the prior art, this utility model provides an insulation monitoring circuit and an insulation monitoring device to solve the problem that the insulation detection equipment of the prior art needs to maintain the isolation between the detected system V+ / V- and the signal system Vo+ / Vo- used for detection, which often requires the use of isolation power supply technology, which has a certain degree of complexity and high cost.

[0005] One embodiment of this utility model provides an insulation monitoring circuit, including an energy storage capacitor and a relay group; the energy storage capacitor is electrically connected to the relay group, and the relay group is configured to switch to electrical connection with a charging circuit, a measuring circuit or an indicating circuit after startup;

[0006] When the relay group is electrically connected to the charging circuit, the energy storage capacitor is connected to the positive and negative terminals of the system power supply through the relay group for charging the energy storage capacitor.

[0007] When the relay group is electrically connected to the measuring circuit, the energy storage capacitor is connected to the positive terminal and the ground terminal of the system power supply through the relay group, so as to discharge the energy storage capacitor.

[0008] The indicating circuit includes a comparison circuit, an indicating module, and an indicating reference unit. When the relay group is electrically connected to the indicating circuit, the comparison circuit is configured to compare the capacitor voltage of the energy storage capacitor with the reference voltage of the indicating reference unit, and indicate the insulation status through the indicating module.

[0009] In one embodiment of this utility model, the relay group is a time relay with time control function, used to switch the connection state of the energy storage capacitor after a predetermined time.

[0010] In one embodiment of this utility model, the indicator circuit has an input port and an output port, the output port being connected to at least the indicator module; the input port is connected to at least a reset switch for receiving a reset signal and performing a reset.

[0011] In one embodiment of this utility model, the indicating module is an indicator light or an audible and visual alarm.

[0012] In one embodiment of this utility model, the energy storage capacitor includes a plurality of capacitors, which are connected in parallel.

[0013] In one embodiment of this invention, the energy storage capacitor is configured to adjust its capacitance value by adjusting the number of capacitors connected in parallel.

[0014] In one embodiment of this utility model, the input terminal of the comparator circuit is connected to the energy storage capacitor and the indicator reference unit respectively; a current loop is formed between the indicator module, the comparator circuit and the system power supply.

[0015] In one embodiment of this utility model, the comparison circuit is configured such that if the reference voltage is less than the comparison threshold of the reference voltage, the current loop between the indicator module, the comparison circuit and the system power supply is in a conducting state, and the indicator module issues an alarm.

[0016] Alternatively, if the reference voltage is greater than the comparison threshold of the reference voltage, the current loop between the indicator module, the comparison circuit and the system power supply is in a conducting state, and the indicator module issues an alarm;

[0017] Alternatively, the reference voltage meets the comparison threshold of the reference voltage, and the current loop between the indicator module, the comparison circuit, and the system power supply is in an open circuit state.

[0018] In one embodiment of this utility model, when the relay group switches from being connected to the charging circuit to being connected to the measuring circuit, the relay group is configured to disconnect the two ends of the energy storage capacitor from the system power supply, and then connect them to the positive terminal and the ground terminal of the system power supply, respectively.

[0019] Alternatively, when the relay group switches from being connected to the measuring circuit to being connected to the indicating circuit, the relay group is configured to disconnect the two ends of the energy storage capacitor from the system power supply and then connect them to the indicating circuit respectively.

[0020] One embodiment of this utility model also discloses an insulation monitoring device, which includes the insulation monitoring circuit described in any of the above embodiments.

[0021] The insulation monitoring circuit and insulation monitoring device provided by this utility model can achieve the following technical effects:

[0022] 1. Using a timer relay group for switching, when the energy storage capacitor is connected to the system power supply through the charging circuit or the indicator circuit, the energy storage capacitor is equivalent to a normal load of the system power supply and does not affect the normal use of the system power supply. At the same time, it achieves complete and reliable isolation between the measurement circuit and the system circuit, avoiding interference with the structure of the circuit under test.

[0023] 2. By using an energy storage capacitor as the energy storage element and a simple comparison circuit to compare the voltage of the energy storage capacitor and the indicating reference unit, the indicating function is realized, achieving qualitative indication. This avoids the use of expensive isolated power supplies and complex current measurement circuits, and can meet the user's monitoring needs at a lower cost.

[0024] 3. The energy storage capacitor obtained by connecting several capacitors in parallel can have its capacitance value adjusted by adjusting the number of capacitors connected in parallel; and the duration of connection to different circuits can be adjusted by adjusting the time parameters of the relay group, thereby enabling monitoring of circuits with different voltage levels and different insulation resistance levels. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0026] Figure 1 This is a circuit diagram illustrating the insulation monitoring circuit of this utility model.

[0027] The annotations in the attached figures are explained as follows:

[0028] 1-Storage capacitor; 2-Relay group; 3-Indicator module; 4-Comparison circuit; 5-Indicator reference unit; A-Charging circuit; B-Measurement circuit; C-Indicator circuit; Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0030] Please refer to Figure 1 One embodiment of this utility model provides an insulation monitoring circuit, which is electrically connected to the system power supply and includes an energy storage capacitor 1 and a relay group 2; the energy storage capacitor 1 is electrically connected to the relay group 2, and the relay group 2 is configured to switch to electrical connection with the charging circuit A, the measuring circuit B or the indicating circuit C after startup;

[0031] When the relay group 2 is electrically connected to the charging circuit A, the energy storage capacitor 1 is connected to the positive and negative terminals of the system power supply through the relay group 2, which is used to charge the energy storage capacitor 1.

[0032] When the relay group 2 is electrically connected to the measurement circuit B, the energy storage capacitor 1 is connected to the positive terminal and the ground terminal of the system power supply through the relay group 2, so as to discharge the energy storage capacitor 1.

[0033] The indicator circuit C includes a comparison circuit 4, an indicator module 3, and an indicator reference unit 5. When the relay group 2 is electrically connected to the indicator circuit C, the comparison circuit 4 is configured to compare the capacitor voltage of the energy storage capacitor 1 with the reference voltage of the indicator reference unit 5, and indicate the insulation status through the indicator module 3.

[0034] Understandably, this embodiment can achieve the following technical effects:

[0035] 1. Use timer relay group 2 for switching to achieve complete and reliable isolation between measurement circuit B and system circuit, avoiding interference with the structure of the circuit under test.

[0036] 2. By using energy storage capacitor 1 as the energy storage element and using a simple comparison circuit 4 to compare the voltage of energy storage capacitor 1 and the voltage of the indicator reference unit 5, the indication function is realized, achieving qualitative indication. This avoids the use of expensive isolated power supplies and complex current measurement circuits B, and can meet the user's monitoring needs at a lower cost.

[0037] In one embodiment of this utility model, the relay group 2 is a time relay with time control function, used to switch the connection state of the energy storage capacitor 1 after a predetermined time.

[0038] Understandably, the time relay can automatically switch the connection state of the energy storage capacitor 1 after a predetermined time, which means that the energy storage capacitor 1 can be charged and discharged within a set time, thereby achieving precise control of the voltage of the energy storage capacitor 1.

[0039] Therefore, this embodiment can reduce human intervention, improve measurement accuracy and system reliability, and reduce cost and energy consumption by using a time relay in the insulation monitoring circuit.

[0040] In one embodiment of the present invention, the indicator circuit C has an input port and an output port, the output port being connected to at least the indicator module 3; the input port being connected to at least a reset switch for receiving a reset signal and performing a reset.

[0041] Understandably, the output port can be used not only to connect to the indicator module 3, but also to the industrial control box or other control systems, so as to realize the recording and collection of insulation performance monitoring data. Alternatively, the output port can be connected to the automation control system to realize linkage with other automation equipment, such as automatically cutting off the power supply or starting the backup system when the insulation condition is abnormal. The input port can receive the reset signal from the reset switch, so that the system can be manually or automatically reset when needed.

[0042] In one embodiment of this utility model, the indicator module 3 is an indicator light or an audible and visual alarm.

[0043] Understandably, indicator lights can provide immediate visual feedback, alerting users by changes in light (such as color changes or flashing) when insulation conditions are abnormal; in addition to visual warnings, audible and visual alarms can also emit sound signals, which is especially important for users working in noisy environments, ensuring they can notice the alarm in a timely manner.

[0044] Therefore, in this embodiment, the indicator module 3 is designed as an indicator light or an audible and visual alarm, which can improve the reliability and user-friendliness of the insulation monitoring circuit and ensure that the user can be reminded in a timely and effective manner when an insulation problem is detected.

[0045] In one embodiment of this utility model, the energy storage capacitor 1 includes a plurality of capacitors, which are connected in parallel.

[0046] The energy storage capacitor 1 is configured to adjust its capacitance value by adjusting the number of capacitors connected in parallel.

[0047] Understandably, by connecting multiple capacitors in parallel, the total capacitance value can be increased, thereby improving the energy storage capacity of energy storage capacitor 1. Furthermore, the capacitance value of energy storage capacitor 1 obtained by connecting several capacitors in parallel can be adjusted by adjusting the number of capacitors connected in parallel.

[0048] Therefore, in this embodiment, the energy storage capacitor 1 is designed as several capacitors connected in parallel. The number of capacitors can be flexibly increased or decreased as needed to adapt to different energy storage requirements and improve the reliability and economy of the insulation monitoring circuit.

[0049] Furthermore, based on this embodiment, by combining the use of time relays as relay group 2, the duration of connection to different circuits can be adjusted by adjusting the time parameters of relay group 2, thereby realizing the monitoring of circuits with different voltage levels and different insulation resistance levels.

[0050] Please refer to Figure 1 In one embodiment of this utility model, the input terminal of the comparator circuit 4 is connected to the energy storage capacitor 1 and the indicator reference unit 5 respectively; a current loop is formed between the indicator module 3, the comparator circuit 4 and the system power supply.

[0051] Understandably, the current loop formed between the indicator module 3, the comparison circuit 4, and the system power supply is used to form a path when an abnormality occurs in the comparison between the energy storage capacitor 1 and the indicator reference unit 5, thereby activating the indicator module 3 to alarm or indicate an abnormality in the insulation performance of the system power supply.

[0052] In one embodiment of this utility model, the comparison circuit 4 is configured such that if the reference voltage is less than the comparison threshold of the reference voltage, the current loop between the indicator module 3, the comparison circuit 4 and the system power supply is in a conducting state, and the indicator module 3 issues an alarm.

[0053] Alternatively, if the reference voltage is greater than the comparison threshold of the reference voltage, the current loop between the indicator module 3, the comparison circuit 4 and the system power supply is in a conducting state, and the indicator module 3 issues an alarm.

[0054] Alternatively, if the reference voltage meets the comparison threshold of the reference voltage, the current loop between the indicator module 3, the comparison circuit 4, and the system power supply is in an open circuit state.

[0055] Please refer to Figure 1 In one embodiment of the present invention, when the relay group 2 switches from being connected to the charging circuit A to being connected to the measuring circuit B, the relay group 2 is configured to disconnect the two ends of the energy storage capacitor 1 from the system power supply, and then connect them to the positive terminal and the ground terminal of the system power supply, respectively.

[0056] Alternatively, when the relay group 2 switches from being connected to the measuring circuit B to being connected to the indicating circuit C, the relay group 2 is configured to disconnect the two ends of the energy storage capacitor 1 from the system power supply and then connect them to the indicating circuit C respectively.

[0057] Based on the above embodiments, it can be understood that the principle of the insulation monitoring circuit of this utility model is as follows:

[0058] 1) Charging phase: Relay group 2 connects the two ends of energy storage capacitor 1 to V+ and V- of the system power supply. The system power supply charges energy storage capacitor 1. Energy storage capacitor 1 can be regarded as an ordinary load under the system power supply and does not affect the use of the circuit in the system power supply. The duration of the charging phase can be set by adjusting the time parameter of relay group 2.

[0059] 2) Measurement Phase: Relay group 2 disconnects the two ends of energy storage capacitor 1 from the system power supply, and then connects them to the PE and V+ terminals of the system power supply respectively. If V+ and PE are not completely insulated at this time, and there is a resistance RPE, the capacitor will discharge through RPE. The discharge rate is related to the value of RPE. The duration of the measurement phase can be set by adjusting the time parameter of relay group 2.

[0060] 3) Indication stage: Relay group 2 disconnects the two ends of energy storage capacitor 1 from the system power supply, and then connects them to the indicator circuit C respectively. For the system circuit, energy storage capacitor 1 and indicator circuit C are equivalent to ordinary loads at this time, and do not affect the use of the circuit.

[0061] During the measurement phase, the capacitor discharges for a specified time. The voltage Vs of the energy storage capacitor 1 at this time is compared with the reference voltage Vr of the indicator reference unit 5. If the capacitor voltage is lower than the reference voltage, the indicator light illuminates. The indicator circuit C has input and output functions; it can output indications to other systems and be reset via an input reset signal.

[0062] 4) The capacitance value of the energy storage capacitor 1, the switching time of the relay group 2, and the reference voltage can be adjusted according to the system voltage level (such as 24V, 5V, etc.) to indicate the value of different insulation resistance RPE.

[0063] 5) Generally, during the measurement phase, the capacitor can be connected to any circuit that needs to be measured, as long as the circuit voltage is within the capacitor's withstand voltage range.

[0064] One embodiment of this utility model also discloses an insulation monitoring device, which includes any one of the insulation monitoring circuits described in the above embodiments.

[0065] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. An insulation monitoring circuit, electrically connected to a system power supply, characterized in that, It includes an energy storage capacitor and a relay group; the energy storage capacitor is electrically connected to the relay group, and the relay group is configured to switch to electrical connection with a charging circuit, a measuring circuit or an indicating circuit after startup; When the relay group is electrically connected to the charging circuit, the energy storage capacitor is connected to the positive and negative terminals of the system power supply through the relay group for charging the energy storage capacitor. When the relay group is electrically connected to the measuring circuit, the energy storage capacitor is connected to the positive terminal and the ground terminal of the system power supply through the relay group, so as to discharge the energy storage capacitor. The indicating circuit includes a comparison circuit, an indicating module, and an indicating reference unit. When the relay group is electrically connected to the indicating circuit, the comparison circuit is configured to compare the capacitor voltage of the energy storage capacitor with the reference voltage of the indicating reference unit, and indicate the insulation status through the indicating module.

2. The insulation monitoring circuit as described in claim 1, characterized in that, The relay group is a time relay with time control function, used to switch the connection state of the energy storage capacitor after a predetermined time.

3. The insulation monitoring circuit as described in claim 1, characterized in that, The indicator circuit has an input port and an output port. The output port is connected to the indicator module at least once. The input port is connected to a reset switch at least once to receive a reset signal and perform a reset.

4. The insulation monitoring circuit as described in claim 1, characterized in that, The indicator module is an indicator light or an audible and visual alarm.

5. The insulation monitoring circuit as described in claim 1, characterized in that, The energy storage capacitor includes several capacitors, which are connected in parallel.

6. The insulation monitoring circuit as described in claim 5, characterized in that, The energy storage capacitor is configured to adjust its capacitance value by adjusting the number of capacitors connected in parallel.

7. The insulation monitoring circuit as described in any one of claims 1-6, characterized in that, The input terminal of the comparator circuit is connected to the energy storage capacitor and the indicator reference unit respectively; a current loop is formed between the indicator module, the comparator circuit and the system power supply.

8. The insulation monitoring circuit as described in claim 7, characterized in that, The comparison circuit is configured such that if the reference voltage is less than a comparison threshold of the reference voltage, the current loop between the indicator module, the comparison circuit, and the system power supply is in a conducting state, and the indicator module issues an alarm. Alternatively, if the reference voltage is greater than the comparison threshold of the reference voltage, the current loop between the indicator module, the comparison circuit and the system power supply is in a conducting state, and the indicator module issues an alarm; Alternatively, the reference voltage meets the comparison threshold of the reference voltage, and the current loop between the indicator module, the comparison circuit, and the system power supply is in an open circuit state.

9. The insulation monitoring circuit as described in claim 1, characterized in that, When the relay group switches from being connected to the charging circuit to being connected to the measuring circuit, the relay group is configured to disconnect the two ends of the energy storage capacitor from the system power supply, and then connect them to the positive terminal and the ground terminal of the system power supply, respectively. Alternatively, when the relay group switches from being connected to the measuring circuit to being connected to the indicating circuit, the relay group is configured to disconnect the two ends of the energy storage capacitor from the system power supply and then connect them to the indicating circuit respectively.

10. An insulation monitoring device, characterized in that, Including the insulation monitoring circuit as described in any one of claims 1-9.

Images