An insulation monitoring device and its control method using triangular waves

Abstract

According to various embodiments of the present invention, an insulation monitoring device includes an impedance disposed between a power line and a system ground. The insulation monitoring device includes: a signal generation circuit for applying a triangular wave signal to the power line via a signal measurement circuit; a signal measurement circuit for measuring a voltage difference across a detection resistor or a current flowing through the detection resistor when the triangular wave signal is applied to the impedance; and a control circuit for acquiring an impedance value of the impedance based on at least one of the voltage difference and the current, and monitoring the impedance value.

Description

Technical Field

[0001] This invention relates to an insulation monitoring device and its control method for preventing accidents by detecting line grounding faults and power quality degradation in an insulation terra (IT) power system. Background Technology

[0002] IT (Insulated Ground) grounding refers to a grounding method where the power lines are not grounded, and the grounding occurs only through the load casing. The advantage of IT grounding is that it ensures continuous system operation, so that even if a line ground fault occurs on any power line, there is time to locate the part of the system that has the fault without stopping system operation.

[0003] However, since the system can operate even in the event of a line-to-ground fault, continuous monitoring of the power line insulation condition is necessary even while the system is running. Therefore, IEC Regulation 61557 (International Electrotechnical Commission) requires the installation of insulation monitoring devices capable of monitoring the insulation condition of the power lines.

[0004] Therefore, also in South Korea, the Ministry of Trade, Industry and Energy announced the certification criteria for Electrical Equipment Technical Standard No. 2019-667 on November 21, 2019, to ensure that energy storage devices using secondary batteries are equipped with appropriate protection and control devices, such as insulation monitoring devices (IMD).

[0005] This insulation monitoring device includes a signal generation circuit positioned between the grounding and power lines. A circuit is formed between the power lines and grounding using an insulation resistor and a capacitor positioned between them, injecting a signal and increasing the detection resistor for voltage detection. Furthermore, a control circuit measures and analyzes the voltage across the detection resistor to detect the voltage when the insulation is in normal condition, and calculates the amplitude of the insulation resistor based on the detected voltage, thereby monitoring the insulation status of the power lines.

[0006] For example, a signal generation circuit can generate a pulse signal and inject it into the circuit. To accurately calculate the amplitude of the insulation resistance, it is necessary to calculate the voltage under normal conditions after the pulse signal polarity is reversed. However, because the pulse signal is discontinuous, if the pulse signal polarity is reversed, the surge caused by the voltage difference of the reverse pulse signal will lead to temporary voltage instability. Therefore, its disadvantage is that the amplitude of the insulation resistance can only be calculated after the voltage has stabilized again after a certain period of time, and it is impossible to monitor the voltage value applied to the capacitor between the power line and ground. Summary of the Invention

[0007] The present invention aims to solve the above-mentioned problems by setting an insulation resistor and a capacitor between the power line and the ground, and injecting a continuous triangular wave signal into the insulation resistor and the capacitor, thereby providing an insulation monitoring device that can prevent surge phenomena caused by pulse signal voltage differences and stably maintain the voltage across the detection resistor.

[0008] Furthermore, when the value of the capacitor placed between the power line and ground cannot be monitored, if an accident occurs and the capacitor value increases abnormally, the total impedance placed between the power line and ground will decrease. Therefore, power to the power line may be lost or ripple may be generated.

[0009] To address the aforementioned problems, this invention provides a monitoring device that, by injecting continuous triangular wave signals into an insulation resistor and a capacitor, can accurately monitor not only the insulation resistor but also the capacitance value of the capacitor.

[0010] According to various embodiments of the present invention, an insulation monitoring device (including an impedance disposed between a power line and a system ground) includes: a signal generation circuit for applying a triangular wave signal to the power line via a signal measurement circuit; a signal measurement circuit for measuring a voltage difference across a detection resistor of the signal measurement circuit or a current flowing through the detection resistor when the triangular wave signal is applied to the impedance; and a control circuit for acquiring an impedance value of the impedance based on at least one of the voltage difference and the current and monitoring the impedance value.

[0011] According to various embodiments of the present invention, a method for controlling an apparatus (including an impedance disposed between a power line and a system ground) includes the following steps: applying a triangular wave signal to the power line via a signal measurement circuit through a signal generation circuit; measuring a voltage difference or a current flowing through a detection resistor of the signal measurement circuit via the signal measurement circuit; obtaining an impedance value of the impedance via the control circuit based on at least one of the voltage difference and the current; and monitoring the impedance value via the control circuit.

[0012] According to an exemplary embodiment of the present invention, the signal generation circuit of the insulation monitoring device has continuity and applies a linear triangular wave signal to the impedance of a specific portion, enabling the insulation monitoring device to provide stable insulation monitoring.

[0013] Furthermore, by injecting a triangular wave signal into the insulating capacitor, not only the insulation resistance but also the capacitance of the capacitor can be monitored, thus providing more accurate insulation monitoring. Attached Figure Description

[0014] Figure 1 This is a block diagram illustrating an exemplary structure of the insulation monitoring device described in various embodiments of the present invention.

[0015] Figure 2 This is a flowchart illustrating the operation of monitoring impedance values ​​in an insulation monitoring device according to an exemplary embodiment of the present invention.

[0016] Figure 3 Described Figure 1 V, I in insulation monitoring device Re and I RC Example diagram.

[0017] Figure 4 This is a block diagram illustrating an exemplary structure of the signal generation circuit described in an embodiment of the present invention.

[0018] Figure 5 This is a flowchart illustrating the operation of the signal generation circuit described in the embodiments of the present invention in generating a triangular wave signal.

[0019] Figure 6 This is a block diagram illustrating an exemplary structure of the signal source described in an embodiment of the present invention.

[0020] Figure 7 This is an exemplary flowchart illustrating the operation of generating a triangular waveform signal by a signal source according to an exemplary embodiment of the present invention.

[0021] Figure 8 An exemplary diagram of the signal shape is described in each step of the operation of a signal source generating a triangular wave-shaped signal according to an embodiment of the present invention.

[0022] Figure 9 This is an exemplary block diagram of the internal configuration of the signal measurement circuit described in an embodiment of the present invention.

[0023] Figure 10 This is a flowchart illustrating the operation of the signal measurement circuit described in an embodiment of the present invention.

[0024] Figure 11 This is an exemplary block diagram of the internal configuration of an analog-to-digital converter disposed between a signal measurement circuit and a control circuit, as described in an embodiment of the present invention.

[0025] Figure 12 This is a flowchart illustrating the operation of the analog-to-digital converter disposed between the signal measurement circuit and the control circuit as described in the embodiments of the present invention. Detailed Implementation

[0026] It should be noted that the technical terms used in this specification are for describing specific embodiments only and are not intended to limit the invention. Furthermore, unless the context clearly indicates otherwise, singular expressions used in this specification include plural expressions. In this specification, phrases such as "consists of" or "includes" should not be construed as necessarily including all the various components or steps described herein, and may exclude certain components or steps, or may include other components or steps, or should be interpreted as more inclusive.

[0027] Furthermore, when describing the technology disclosed in this specification, detailed descriptions of related known technologies are omitted if it is determined that such detailed descriptions may obscure the essential aspects of the technology disclosed in this specification.

[0028] In describing each figure, the same reference numerals are used for the same elements. Furthermore, terms such as "first" and "second" may be used to describe various components, but components should not be limited by the terms. These terms are used only to distinguish one component from another.

[0029] Common terms (such as those defined in a dictionary) should be interpreted as having meanings consistent with their meanings in the relevant technical context, and should not be interpreted as having ideal or overly formal meanings unless explicitly defined in this specification.

[0030] Figure 1 This is a block diagram illustrating an exemplary structure of the insulation monitoring device described in various embodiments of the present invention.

[0031] Reference Figure 1 The insulation monitoring device 10 described in various embodiments of the present invention includes a coupling resistor 180 (Rc) connected to a system power line 170 (hereinafter referred to as the power line); a signal generation circuit 130 that applies a triangular wave signal to the power line 170 via the coupling resistor 180 and a signal measurement circuit 120; an impedance 160 disposed between the power line 170 and ground, and consisting of an insulation resistor Re and a capacitor Ce; a signal measurement circuit 120 including a detection resistor Rm; and a control circuit 100 for controlling other components and calculating and monitoring the value of the impedance 160 based on at least one of the voltage difference across the detection resistor and the current flowing through the detection resistor. Although Figure 1 Not shown, the insulation monitoring device 10 includes a memory (not shown) for storing data input to and / or various data output from the control circuit 100; and controls controlled by the control circuit 100, and may also include a display (not shown) for displaying the status of the impedance 160.

[0032] Figure 1This is an example of a single-phase power line 170, but the system power line 170 can be a multi-phase power line. For example, the system power line 170 can be a three-phase power line (R, S, T). The coupling resistor 180 can be configured as a resistor disposed on a multi-phase power line (e.g., configured as R line, S line, and T line in the three-phase case).

[0033] Figure 1 The components shown are not essential components for implementing the insulation monitoring device 10. Therefore, the insulation monitoring device 10 of the present invention may include more or fewer components than those described above.

[0034] Figure 2 This is a flowchart illustrating the operation of monitoring impedance values ​​in an insulation monitoring device according to an exemplary embodiment of the present invention. Figure 3 Described Figure 1 Example diagram of V, IRe, and IRC in an insulation monitoring device.

[0035] In step 210, the signal generation circuit 130 applies a triangular wave signal to the power line 170 via the signal measurement circuit 120. The triangular wave signal may refer to a signal with a periodically repeating triangular waveform. For example, the amplitude of the triangular wave signal may be between -50V and +50V. The triangular wave signal generated by the signal generation circuit 130 is applied to the power line 170 and the impedance 160 provided between the power line 170 and the connection via the signal measurement circuit 120 and the coupling resistor 180.

[0036] In step 220, when the triangular wave signal is applied to impedance 160, signal measurement circuit 120 can measure the voltage difference across detection resistor Rm or the current flowing through detection resistor Rm. For example, signal measurement circuit 120 can use a current transformer or the like to measure the current flowing through detection resistor Rm. Applying the triangular wave signal to impedance 160 may mean that signal measurement circuit 120, signal generation circuit 130, coupling resistor 180, power line 170, and impedance 160 form a closed circuit. When the closed circuit is formed by the components of the aforementioned insulation monitoring device 10, the voltage difference between signal measurement circuits and / or the current flowing through the signal measurement circuits (e.g., the voltage difference across detection resistor Rm and / or the current flowing through detection resistor Rm) can be determined, and signal measurement circuit 120 can measure the voltage difference and / or current. The voltage difference and / or current measured by signal measurement circuit 120 can be input to control circuit 100.

[0037] In step 230, the control circuit 100 acquires and monitors the impedance value of the impedance 160 based on at least one of the voltage difference and current. The control circuit 100 acquires the voltage difference or current flowing through the signal measurement circuit or the detection resistor, and uses at least one of the acquired voltage difference or current values ​​to calculate the values ​​of the insulation resistance Re and capacitance Ce included in the impedance 160. The control circuit 100 presets the respective values ​​of the insulation resistance Re and capacitance Ce if they are within normal ranges, and monitors whether the calculated values ​​of the insulation resistance Re and capacitance Ce are within normal ranges. Values ​​of the insulation resistance Re and capacitance Ce within normal ranges may indicate that no line-to-ground fault has occurred and the closed circuit is functioning normally.

[0038] According to one embodiment, the control circuit 100 calculates the voltage value V of the power line 170 and the insulation resistance current I flowing through the insulation resistor Re and the capacitor Ce based on the voltage difference between the detection resistors. Re and capacitor current I Ce Each graph can be Figure 3 The diagram shown. However, Figure 3 The diagram is illustrative; the ranges of current and voltage values ​​may vary. As described above, the voltage V of power line 170 and the insulation resistor current I can be determined by the total impedance of the closed circuit. Re and capacitor current I Ce For example, the voltage value V of power line 170 can have a voltage value where the voltage drops from the triangular wave signal of signal generation circuit 130 through sensing resistor Rm and coupling resistor 180. Therefore, control circuit 100 can use the voltage difference Rm across the sensing resistor and the voltage difference across coupling resistor 180 to calculate the voltage value applied to insulation resistor Re and capacitor Ce, and obtain the current value flowing through insulation resistor Re and capacitor Ce based on the calculated voltage value. Furthermore, control circuit 100 can obtain the values ​​of insulation resistor Re and capacitor Ce based on the calculated voltage value, insulation resistor Re, and the current value flowing through insulation resistor Re and capacitor Ce.

[0039] The current applied to each insulation resistor Re and capacitor Ce is the same as the current flowing through the sense resistor Rm, as shown below.

[0040] Mathematical Formula 1

[0041]

[0042] Furthermore, the value of the insulation resistor can be expressed as Figure 3 The ratio of the voltage difference across the insulation resistor to the current difference flowing through the insulation resistor between specific times t1 and t2 is expressed as follows.

[0043] Mathematical formula 2

[0044]

[0045] Furthermore, based on the two equations above, the value of the capacitor can be expressed as follows.

[0046] Mathematical Formula 3

[0047]

[0048] According to one embodiment, when the current flowing through capacitor Ce remains constant for a predetermined time, control circuit 100 can acquire and monitor the values ​​of insulation resistor Re and capacitor Ce. The predetermined time can be arbitrarily set so that the values ​​of the insulation resistor and capacitor can be accurately measured. Due to the periodic change in the slope of the triangular wave signal, the current flowing through capacitor Ce may resemble... Figure 3 capacitor current I Ce The same change occurs. Because the triangular wave signal exhibits linearity as a linear function across all cross-sections except the inflection point, the capacitor current I... Ce It may have a constant value during the period except for the cross-section around the inflection point. This is because it only has a constant value during the period of the capacitor current I. Ce When measuring insulation resistance and capacitor under stable conditions, the capacitor current I Ce Only then can accurate results be obtained if the capacitor current I... Ce By maintaining a constant value for a predetermined time, control circuit 100 can calculate the values ​​of the insulation resistance and capacitor (e.g., Figure 3 The interval period p between t1 and t2 is given above. It has been described that the values ​​of the insulation resistor and the capacitor are calculated using the voltage difference across the sensing resistor. However, it will be apparent to those skilled in the art that the signal measurement circuit uses the current flowing through the sensing resistor (measured using a current transformer) to calculate the insulation resistor and the capacitor.

[0049] According to one embodiment, the insulation monitoring device 10 may include a display (not shown) that can display various data based on the operation of the insulation monitoring device 10. For example, the display may display impedance values, monitoring results, etc. For example, since the insulation monitoring device 10 continuously calculates the amplitude of the insulation resistance, the display shows the amplitude of impedance change over time in the form of a curve, thereby displaying the amplitude change of impedance and monitoring results in real time. In addition, the insulation monitoring device 10 may include at least one input unit (not shown) for receiving user input. For example, the input unit may be configured to include at least one hardware button or touch button. Alternatively, when the display is in the form of a touch screen, the display may be used as the input unit.

[0050] According to one embodiment, the insulation monitoring device 10 further includes a communication module (not shown) capable of wireless or wired communication with a preset user terminal. The communication unit can notify the user terminal of information related to a line-to-ground fault occurring in the power line 170. Here, the line-to-ground fault in the power line 170 can be detected by the control circuit 100 of the insulation monitoring device 10, and can be detected based on a calculated impedance value.

[0051] Figure 4 This is a block diagram illustrating an exemplary structure of the signal generation circuit described in an embodiment of the present invention. Figure 5 This is a flowchart illustrating the operation of the signal generation circuit described in the embodiments of the present invention in generating a triangular wave signal.

[0052] Reference Figure 4 The signal generation circuit 120 of the present invention may include a signal source 410, an operational amplifier 420 (OP Amp), a boost circuit 430, and a feedback circuit 440. In step 510, the signal source 410 generates a triangular waveform signal, which forms the basis for outputting the triangular waveform signal from the signal generation circuit 120. For example, the signal output from the signal source 410 may have an amplitude greater than 0V and less than or equal to 3.3V. In step 520, the operational amplifier 420 may be used to amplify the signal from the signal source 410, giving the signal amplitude a first range. For example, the first range may be set such that the signal from the signal source 410 has a value greater than -3.85V and less than or equal to 2.93V. In step 530, the boost circuit 430 may be used to amplify the signal from the operational amplifier 420, giving the signal amplitude of the operational amplifier 420 a second range greater than the first range. For example, the second range may be set such that the signal from the boost circuit 430 has a value from -32V to 32V, specifically, a value greater than -50V and less than or equal to 50V. In step 540, the feedback circuit 440 can feed back the output of the boost circuit 430, giving the output of the signal generation circuit 120 a predetermined gain. The feedback circuit 440 can feed back the output of the signal generation circuit 120 with an amplitude greater than or equal to a specific value. For example, the feedback circuit 440 can feed back the output of the signal generation circuit 120 based on the value of a resistor set in the feedback circuit 440. The above-described limitations are merely exemplary; different configurations are possible, and the above examples do not limit the scope of the invention.

[0053] Figure 6 This is a block diagram illustrating an exemplary structure of the signal source described in an embodiment of the present invention. Figure 7 This is an exemplary flowchart illustrating the operation of generating a triangular waveform signal by a signal source according to an exemplary embodiment of the present invention. Figure 8 An exemplary diagram illustrating the signal shape in each step of the operation of the signal source generating a triangular wave-shaped signal according to an embodiment of the present invention is provided.

[0054] Reference Figure 6 The signal source 410 described in this embodiment of the invention may include a phase accumulator 610, a phase-to-amplitude converter 620, a digital-to-analog converter 630, and a filter 640. The phase accumulator 610, phase-to-amplitude converter 620, and digital-to-analog converter 630 can be configured for each clock cycle f. clk Update as needed. (Refer to...) Figure 7 In step 710, the phase accumulator 610 receives the phase value as each clock cycle f. clk The phase accumulator 610 receives the phase value as input for each clock cycle f and accumulates the received phase value. clk When the input phase value is received, the accumulated phase value may increase or decrease. For example, the phase accumulator 610 increases or decreases the accumulated phase value based on the input phase value, such as... Figure 8 The output diagram of the phase accumulator is shown, and the output of the phase accumulator 610 can have a triangular waveform. In step 720, the phase-amplitude converter 620 can be used to convert the accumulated phase value into an amplitude value. For example, the accumulated phase value can be converted into a corresponding amplitude value, in which case the amplitude value can be a digital value. Since the amplitude value has a digital value, such as... Figure 8 As shown in the diagram, phase-amplitude converter 620 outputs a digital amplitude value for each clock cycle. In step 730, analog-to-analog converter 630 converts the amplitude value into an analog value. In step 740, filter 640 flattens the converted analog value. The output values ​​of analog-to-analog converter 630 and filter 640 can each have a digital amplitude value. Figure 8 The output diagrams of the analog converter 630 and filter 640 are similar. After being flattened by filter 640, the output of signal source 410 can be a triangular waveform with linearity.

[0055] Figure 9 This is an exemplary block diagram of the internal configuration of the signal measurement circuit described in an embodiment of the present invention. Figure 10 This is a flowchart illustrating the operation of the signal measurement circuit described in an embodiment of the present invention.

[0056] Reference Figure 9The insulation monitoring device 10 described in various embodiments of the present invention includes a coupling resistor 180 (Rc) connected to the system power line 170; a signal generation circuit 130 that applies a triangular wave signal to the power line 170 via the coupling resistor 180 and the signal measurement circuit 120; an impedance 160 disposed between the power line 170 and ground, and consisting of an insulation resistor Re and a capacitor Ce; a signal measurement circuit 120 including a detection resistor Rm; and a control circuit 100 for controlling other components and calculating and monitoring the impedance 160 value based on at least one of the voltage difference across the detection resistor and the current flowing through the detection resistor. Since the above configuration has been... Figures 1 to 8 The details are described in detail in the text, so they will not be repeated here.

[0057] The signal measurement circuit 120 described in this embodiment of the invention may include a detection resistor 900, a first analog filter 950, an amplifier circuit 910, and a second analog filter 960. The insulation monitoring device 10 may further include an analog-to-digital converter 102 (ADC). In step 1010, the first analog filter 950 can eliminate noise from the voltage difference applied to the detection resistor 900 or the current flowing through the detection resistor 900. The first analog filter 950 may be disposed between the detection resistor 900 and the amplifier circuit 910. In step 1020, the amplifier circuit 910 can amplify the voltage difference applied to the detection resistor 900 or the current flowing through the detection resistor 900. In step 1030, the second analog filter 960 can eliminate noise from the voltage difference or current amplified by the amplifier circuit 910. The second analog filter 960 may be connected between the amplifier circuit 910 and the analog-to-digital converter 102. In step 1040, the analog-to-digital converter 102 can convert the voltage difference or current amplified by the amplifier circuit 910 into a digital value and input the result to the control circuit. The first analog filter 950 and the second analog filter 960 can be configured alternately or simultaneously. When the first analog filter 950 and the second analog filter 960 are configured simultaneously, when minor noise not eliminated by the first analog filter 950 is eliminated by the second analog filter 960 and the measured voltage or current is amplified by the amplifier circuit 910, a more accurate measured voltage or current can be input to the analog-to-digital converter 102. For example, the first analog filter 950 and the second analog filter 960 can be hardware filters or filters with different passband, cutoff band, roll-off, and phase delay characteristics.

[0058] Figure 11 This is an exemplary block diagram of the internal configuration of an analog-to-digital converter disposed between a signal measurement circuit and a control circuit, as described in an embodiment of the present invention. Figure 12 This is a flowchart illustrating the operation of the analog-to-digital converter disposed between the signal measurement circuit and the control circuit as described in the embodiments of the present invention.

[0059] Reference Figure 11 The insulation monitoring device 10 described in various embodiments of the present invention includes a coupling resistor 180 (Rc) connected to the system power line 170; a signal generation circuit 130 that applies a triangular wave signal to the power line 170 via the coupling resistor 180 and the signal measurement circuit 120; an impedance 160 disposed between the power line 170 and ground, and consisting of an insulation resistor Re and a capacitor Ce; a signal measurement circuit 120 including a detection resistor Rm; and a control circuit 100 for controlling other components and calculating and monitoring the value of the impedance 160 based on at least one of the voltage difference across the detection resistor and the current flowing through the detection resistor. Since the above configuration has been... Figures 1 to 8 The details are described in detail in the text, so they will not be repeated here.

[0060] According to one embodiment, the insulation monitoring device 10 may include an analog-to-digital converter 102 (ADC) disposed between a signal measurement circuit 120 and a control circuit 100. The ADC 102 is a filter for eliminating noise present within the insulation monitoring device 10 and may include a conversion circuit 1100 and a digital filter 1110. In step 1210, the conversion circuit 1100 may convert an amplified voltage difference or current into a digital value. In step 1220, noise in the digital value input to the control circuit may be eliminated. The digital filter 1110 may be disposed between the conversion circuit 1100 and the control circuit 100. The digital filter 1110 eliminates noise in the voltage or current value input to the control unit 100, thereby eliminating noise within the insulation monitoring device 10. The digital filter 1110 may be a software filter, and the filter's properties (e.g., cutoff frequency and order) may be changed according to the characteristics of the noise components present in the insulation monitoring device 10.

[0061] According to various embodiments of the present invention, an insulation monitoring device (including an impedance disposed between a power line and a system ground) may include: a signal generation circuit for applying a triangular wave signal to the power line via a signal measurement circuit; a signal measurement circuit for measuring a voltage difference across a detection resistor of the signal measurement circuit or a current flowing through the detection resistor when the triangular wave signal is applied to the impedance; and a control circuit for acquiring an impedance value of the impedance based on at least one of the voltage difference and the current and monitoring the impedance value.

[0062] According to an embodiment of the present invention, the signal generation circuit includes: a signal source for generating a triangular waveform signal; an operational amplifier for amplifying the signal source so that the amplitude of the signal has a first range; a boost circuit for amplifying the signal of the operational amplifier so that the amplitude of the signal of the operational amplifier has a second range greater than the first range; and a feedback circuit for feeding back the output of the boost circuit so that the output of the signal generation circuit has a predetermined gain.

[0063] According to one embodiment of the present invention, the signal source includes: a phase accumulator for receiving the phase value of each clock cycle and accumulating the received phase values; a phase-to-amplitude converter for converting the accumulated phase values ​​into amplitude values; a digital-to-analog converter for converting the amplitude values ​​into analog values; and a filter for flattening the converted analog values.

[0064] According to one embodiment of the present invention, the impedance includes an insulation resistor and a capacitor, wherein the control circuit acquires the current value flowing through each insulation resistor or capacitor based on at least one of voltage difference or current, and acquires the values ​​of the insulation resistor and the capacitor when the current value flowing through the capacitor remains constant for a predetermined time, so as to monitor the values ​​of the insulation resistor and the capacitor.

[0065] According to one embodiment of the present invention, the monitoring device further includes a display, wherein the control circuit displays the monitoring results via the display.

[0066] According to one embodiment of the present invention, the signal measurement circuit further includes: an amplifier circuit for amplifying the voltage difference or current across a detection resistor; an analog-to-digital converter (ADC) for converting the voltage difference or current amplified by the amplifier circuit into a digital value and inputting it to the control circuit; and at least one of a first analog filter and a second analog filter, wherein the first analog filter is disposed between the detection resistor and the amplifier circuit for eliminating noise from the voltage difference or current applied across the detection resistor, and the second analog filter is connected between the amplifier circuit and the ADC for eliminating noise from the voltage difference or current amplified in the amplifier circuit.

[0067] According to one embodiment of the present invention, the analog-to-digital converter further includes: a converter for converting the amplified voltage difference into a digital value; and a digital filter disposed between the conversion circuit and the control circuit for eliminating noise in the digital value input to the control circuit.

[0068] According to various embodiments of the present invention, a method for controlling an apparatus (including an impedance disposed between a power line and a system ground) includes the following steps: applying a triangular wave signal to the power line via a signal generation circuit and a signal measurement circuit; when the triangular wave signal is applied to the impedance, measuring the voltage difference across a detection resistor of the signal measurement circuit or the current flowing through the detection resistor via the signal measurement circuit; and obtaining the impedance value of the impedance based on at least one of the voltage difference and the current via a control circuit.

[0069] According to one embodiment of the present invention, the step of applying a triangular wave signal includes: generating a triangular waveform signal through a signal source; amplifying the signal from the signal source through an operational amplifier to give the amplitude of the signal a first range; amplifying the signal from the operational amplifier through a boost circuit to give the amplitude of the operational amplifier a second range greater than the first range; and feeding back the output of the boost circuit through a feedback circuit to give the output of the signal generation circuit a predetermined gain.

[0070] According to one embodiment of the present invention, generating a triangular waveform signal by a signal source includes the following steps: receiving the phase value of each clock cycle through a phase accumulator and accumulating the received phase values; converting the accumulated phase values ​​into amplitude values ​​through a phase-to-amplitude converter; converting the amplitude values ​​into analog values ​​through a digital-to-analog converter; and flattening the converted analog values ​​through a filter.

[0071] According to one embodiment of the present invention, wherein the impedance includes an insulation resistor and a capacitor, and wherein the method further includes the following steps: obtaining, via the control circuit, a current value flowing through each insulation resistor and capacitor based on at least one of the voltage difference and the current; and obtaining the values ​​of the insulation resistor and the capacitor when the current value flowing through the capacitor via the control circuit remains constant for a predetermined time, so as to monitor the values ​​of the insulation resistor and the capacitor.

[0072] According to one embodiment of the present invention, the method further includes the control circuit displaying the monitoring results via a display.

[0073] According to an embodiment of the present invention, the method further includes the following steps: eliminating noise of voltage applied to a sensing resistor or current flowing through a sensing resistor using a first analog filter, wherein the first analog filter is disposed between the sensing resistor and an amplification circuit; amplifying the voltage difference or current on the sensing resistor using the amplification circuit; eliminating the voltage difference or current noise amplified by the amplification circuit using a second analog filter, wherein the second analog filter is connected between the amplification circuit and an analog-to-digital converter (ADC); and converting the voltage difference or current amplified by the amplification circuit into a digital value using the analog-to-digital converter and inputting it to a control circuit.

[0074] According to one embodiment of the present invention, the method further includes the following steps: converting the amplified voltage difference or the current into a digital value by a converter; and eliminating noise in the digital value input to the control circuit by a digital filter, and inputting the noise into the control circuit.

Claims

1. An insulation monitoring device, comprising an impedance disposed between a power line and a system ground, the insulation monitoring device comprising: A coupling resistor, which is connected to the power line; A signal generation circuit is used to apply a triangular wave signal to the power line through a signal measurement circuit. A signal measurement circuit is used to measure the voltage difference across the detection resistor or the current flowing through the detection resistor when a triangular wave signal is applied to an impedance. A control circuit is configured to acquire and monitor the impedance value based on at least one of voltage difference and current. The impedance includes insulation resistors and capacitors. The control circuit is further configured to: The voltage difference across the insulation resistor is obtained based on the voltage difference across the detection resistor and the voltage difference across the coupling resistor. The value of the insulation resistor is obtained by measuring the ratio of the voltage difference across the insulation resistor between the first time point (t1) and the second time point (t2) to the current difference flowing through the insulation resistor. At the second time point (t2), the value of the capacitor is obtained based on the value of the insulation resistor.

2. The insulation monitoring device according to claim 1, wherein, The signal generation circuit includes: A signal source used to generate triangular waveform signals; An operational amplifier is used to amplify the signal from the signal source so that the amplitude of the signal has a first range; A boost circuit is used to amplify the signal of the operational amplifier, so that the signal amplitude of the operational amplifier has a second range greater than the first range; and A feedback circuit is used to provide feedback on the output of the boost circuit, so that the output of the signal generation circuit has a predetermined gain.

3. The insulation monitoring device according to claim 2, wherein, The signal source includes: A phase accumulator is used to receive the phase value of each clock cycle and accumulate the received phase values. A phase-to-amplitude converter is used to convert accumulated phase values ​​into amplitude values. A digital-to-analog converter (DAC) is used to convert amplitude values ​​into analog values; and A filter is used to flatten the analog values ​​of the transformation.

4. The insulation monitoring device according to claim 1, in, The control circuit acquires the current value flowing through each of the insulation resistor and the capacitor based on at least one of voltage difference or current, and acquires the values ​​of the insulation resistor and the capacitor when the current value flowing through the capacitor remains constant for a predetermined time, in order to monitor the values ​​of the insulation resistor and the capacitor.

5. The insulation monitoring device according to claim 1, in, The monitoring device further includes a display. The control circuit displays the monitoring results via a monitor.

6. The insulation monitoring device according to claim 1, in, The signal measurement circuit further includes: An amplifier circuit is used to amplify the voltage difference or current of the sensing resistor; An analog-to-digital converter (ADC) is used to convert the voltage difference or current amplified by the amplifier circuit into a digital value and input it to the control circuit; and At least one of a first analog filter and a second analog filter, wherein the first analog filter is connected between the sensing resistor and the amplification circuit to eliminate noise from the voltage difference or current applied across the sensing resistor, and the second analog filter is connected between the amplification circuit and the analog-to-digital converter to eliminate noise from the voltage difference or current amplified in the amplification circuit.

7. The insulation monitoring device according to claim 6, wherein, The analog-to-digital converter further includes: A converter used to convert amplified voltage differences into digital values; and A digital filter is disposed between the converter and the control circuit to eliminate noise in the digital values ​​input to the control circuit.

8. A method for controlling a device, the device comprising an impedance disposed between a power line and a system ground and a coupling resistor connected to the power line, wherein the method comprises the following steps: The triangular wave signal is applied to the power line via the signal generation circuit and the signal measurement circuit. When the triangular wave signal is applied to the impedance, the voltage difference across the detection resistor of the signal measurement circuit or the current flowing through the detection resistor is measured by the signal measurement circuit. The impedance value is obtained by the control circuit based on at least one of the voltage difference and the current. as well as The impedance value is monitored by a control circuit. The impedance includes insulation resistors and capacitors. Monitoring the impedance value via the control circuit includes: The voltage difference across the insulation resistor is obtained based on the voltage difference across the detection resistor and the voltage difference across the coupling resistor. The value of the insulation resistor is obtained by measuring the ratio of the voltage difference across the insulation resistor between the first time point (t1) and the second time point (t2) to the current difference flowing through the insulation resistor. At the second time point (t2), the value of the capacitor is obtained based on the value of the insulation resistor.

9. The method according to claim 8, wherein, The steps for applying a triangular wave signal include the following: A triangular waveform signal is generated by a signal source; The signal from the signal source is amplified by an operational amplifier so that the amplitude of the signal has a first range; The signal of the operational amplifier is amplified by a boost circuit, so that the signal amplitude of the operational amplifier has a second range greater than the first range; and The output of the boost circuit is fed back through a feedback circuit, so that the output of the signal generation circuit has a predetermined gain.

10. The method according to claim 9, wherein, The steps for generating a triangular waveform signal using a signal source include the following: The phase value of each clock cycle is received and accumulated using a phase accumulator. The accumulated phase value is converted into an amplitude value through a phase-to-amplitude converter; The amplitude value is converted into an analog value using a digital-to-analog converter; and The analog value is flattened and transformed by a filter.

11. The method according to claim 8, in, The method further includes the following steps: The control circuit obtains the current value flowing through each of the insulation resistor and the capacitor based on at least one of the voltage difference and the current; and When the current flowing through the capacitor through the control circuit remains constant for a predetermined time, the values ​​of the insulation resistor and the capacitor are obtained through the control circuit to monitor the values ​​of the insulation resistor and the capacitor.

12. The method according to claim 8, wherein, The method further includes the control circuit displaying the monitoring results via a display.

13. The method according to claim 8, wherein, The method further includes the following steps: The noise of the voltage applied to the sensing resistor or the current flowing through the sensing resistor is eliminated by a first analog filter, wherein the first analog filter is disposed between the sensing resistor and the amplifier circuit. The voltage difference or current across the detection resistor is amplified by an amplification circuit; The voltage difference or current noise amplified by the amplifier circuit is eliminated by a second analog filter, wherein the second analog filter is connected between the amplifier circuit and the analog-to-digital converter (ADC); and The voltage difference or current amplified by the amplifier circuit is converted into a digital value by an analog-to-digital converter and then input to the control circuit.

14. The method according to claim 13, wherein, The method further includes the following steps: The amplified voltage difference or the current is converted into a digital value by a converter; and The noise of the digital value input to the control circuit is eliminated by a digital filter, and the digital value is then input to the control circuit.

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