Electrical parameter measuring device

Abstract

The invention discloses an electrical parameter measuring device which comprises a zero-cross detection module, a control module and a plurality of analog-to-digital converters. The input end of the zero-cross detection module is connected with an alternating current signal, and the output end of the zero-cross detection module is connected with the first input end of the control module and used for converting the alternating current signal into a direct current square wave signal with the same frequency and inputting the direct current square wave signal into the control module; the control module is used for measuring the period of the direct-current square wave signal and determining the frequency of the alternating-current signal according to the period of the direct-current square wave signal; the plurality of analog-to-digital converters are connected in a daisy chain manner, the second input end of the control module is connected with the data output end of the last daisy chain type analog-to-digital converter, and the control module is also used for sending chip selection signals and clock signals to the analog-to-digital converters; and the plurality of analog-to-digital converters are controlled to simultaneously acquire the multi-phase electrical parameters according to the chip selection signals and the clock signals. The problems that electrical parameter measurement is not comprehensive and the number of sampling channels is small can be solved.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and in particular to an electrical parameter measuring device. Background Art

[0002] Electrical testing is to test and verify the insulation performance, electrical characteristics and mechanical properties of each electrical equipment in the electrical system in accordance with the relevant provisions of standards, regulations and specifications before the electrical system and electrical equipment are put into use, in order to determine whether there are any quality problems in installation or manufacturing, and to determine whether the newly installed or operating electrical equipment can be put into operation normally. Through these tests and verifications, defects, errors and quality problems of electrical equipment during manufacturing and installation can be discovered and eliminated in a timely manner to ensure that the electrical system and electrical equipment can be put into operation normally. Therefore, the comprehensiveness of electrical parameter measurement in electrical test instruments, as well as the accuracy and real-time nature of data are particularly important.

[0003] The existing electrical parameter measurement devices have the problems of incomplete electrical parameter measurement and a small number of sampling channels. Summary of the invention

[0004] The invention provides an electrical parameter measuring device to solve the problems of incomplete electrical parameter measurement and a small number of sampling channels.

[0005] The embodiment of the present invention provides an electrical parameter measuring device, comprising: a zero-crossing detection module, a control module and a plurality of analog-to-digital converters; an input end of the zero-crossing detection module is connected to an AC signal, an output end of the zero-crossing detection module is connected to a first input end of the control module, and is used to convert the AC signal into a DC square wave signal of the same frequency and input it into the control module; the control module is used to measure the period of the DC square wave signal, and determine the frequency of the AC signal according to the period of the DC square wave signal; a plurality of analog-to-digital converters are daisy-chained, a second input end of the control module is connected to a data output end of the last analog-to-digital converter in the daisy-chain, and the control module is also used to send a chip select signal and a clock signal to each analog-to-digital converter, so as to control the plurality of analog-to-digital converters to simultaneously collect multi-phase electrical parameters according to the chip select signal and the clock signal.

[0006] Optionally, the zero-crossing detection module includes a comparator, a first resistor, a second resistor, a third resistor and a first capacitor; the first end of the first resistor serves as the input end of the zero-crossing detection module, and the second end of the first resistor is connected to the in-phase input end of the comparator; the first end of the second resistor is connected to the first reference voltage, and the second end of the second resistor is connected to the inverting input end of the comparator; the first end of the third resistor is connected to the comparison output end of the comparator and serves as the output end of the zero-crossing detection module, and the second end of the third resistor is grounded; the first end of the first capacitor is connected to the first power supply end of the comparator and is connected to the first voltage, the second end of the first capacitor is grounded, and the second power supply end of the comparator is grounded; the comparator is used to output a first level signal through the comparison output end when the voltage of the AC signal is greater than the first reference voltage; and output a second level signal through the comparison output end when the voltage of the AC signal is less than the first reference voltage, wherein the first level signal and the second level signal are signals with opposite high and low levels.

[0007] Optionally, the analog-to-digital converter includes an analog-to-digital conversion chip, a second capacitor, a third capacitor, a fourth capacitor and a magnetic bead; the first end of the second capacitor is connected to the reference voltage pin of the analog-to-digital conversion chip and connected to the second reference voltage, and the second end of the second capacitor is grounded; the first end of the third capacitor is grounded, and the second end of the third capacitor is connected to the analog power pin of the analog-to-digital conversion chip and connected to the second voltage; the first end of the fourth capacitor is grounded, and the second end of the fourth capacitor is respectively connected to the first end of the magnetic bead and the digital power pin of the analog-to-digital conversion chip; the second end of the magnetic bead is connected to the second voltage; the serial clock pin of the analog-to-digital conversion chip is connected to the clock signal, and the conversion start pin of the analog-to-digital conversion chip is connected to the chip select signal.

[0008] Optionally, the electrical parameter measuring device also includes a GPS module, which is used to receive a timing signal sent by a satellite and generate a second pulse signal according to the timing signal; the control module is used to determine the phase of the AC signal according to the second pulse signal.

[0009] Optionally, the electrical parameter measuring device also includes a DC power conversion module, which is used to convert the third voltage into a first voltage to power the zero-crossing detection module, the control module and multiple analog-to-digital converters; wherein the third voltage is greater than the first voltage.

[0010] Optionally, the DC power conversion module includes a step-down chip, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a fourth resistor, a fifth resistor, a sixth resistor and a first inductor; the first end of the fifth capacitor is connected to the input pin of the step-down chip and is connected to a third voltage, and the second end of the fifth capacitor is grounded; the sixth capacitor is connected in parallel with the fifth capacitor; the first end of the seventh capacitor is connected to the bootstrap pin of the step-down chip, and the second end of the seventh capacitor is connected to the first end of the first inductor; the first end of the eighth capacitor is connected to the second end of the first inductor and the switch pin of the step-down chip, and is connected to the first voltage, and the second end of the eighth capacitor is grounded; the first end of the fourth resistor is connected to the input pin of the step-down chip, and the second end of the fourth resistor is connected to the enable pin of the step-down chip; the first end of the fifth resistor is connected to the feedback pin of the step-down chip, and the second end of the fifth resistor is grounded; the first end of the sixth resistor is connected to the first end of the fifth resistor, the second end of the sixth resistor is connected to the second end of the first inductor, and the ninth capacitor is connected in parallel with the sixth resistor.

[0011] Optionally, the electrical parameter measuring device further includes a power monitoring module, which is respectively connected to the control module and the DC power conversion module and is used to monitor whether the first voltage is normal, and reset the control module when the first voltage is abnormal.

[0012] Optionally, the power monitoring module includes a power monitoring chip, a tenth capacitor and a seventh resistor; the first end of the tenth capacitor is connected to the power pin of the power monitoring chip and connected to the first voltage, and the second end of the tenth capacitor is grounded; the first end of the seventh resistor is connected to the reset output pin of the power monitoring chip, and the second end of the seventh resistor is connected to the first voltage.

[0013] Optionally, the electrical parameter measuring device further includes a communication module, which is communicatively connected to the control module and is used for enabling the control module to communicate with a host computer.

[0014] Optionally, the communication module includes a CAN transceiver chip, an eleventh capacitor, a twelfth capacitor, an eighth resistor, a first transient voltage suppression diode and a second transient voltage suppression diode; the first end of the eleventh capacitor is connected to the first power supply pin of the CAN transceiver chip and is connected to the first voltage, and the second end of the eleventh capacitor is grounded; the first end of the twelfth capacitor is connected to the second power supply pin of the CAN transceiver chip and is connected to the third voltage, and the second end of the twelfth capacitor is grounded; the first end of the eighth resistor is connected to the first differential signal input and output pin of the CAN transceiver chip, and the second end of the eighth resistor is connected to the second differential signal input and output pin of the CAN transceiver chip; the first transient voltage suppression diode is connected to the eighth resistor in parallel; the first end of the second transient voltage suppression diode is connected to the first end of the eighth resistor, the second end of the second transient voltage suppression diode is connected to the second end of the eighth resistor, and the third end of the second transient voltage suppression diode is grounded; the send data input pin and the receive data output pin of the CAN transceiver chip are both connected to the control module.

[0015] The electrical parameter measuring device of the embodiment of the present invention is provided with a zero-crossing detection module, which can convert the connected AC signal into a DC square wave signal of the same frequency. The control module measures the period of the DC square wave signal, and then determines the frequency of the AC signal, thereby realizing the measurement of the frequency of the AC signal. A plurality of analog-to-digital converters are daisy-chained. This connection mode enables the control module to control the plurality of analog-to-digital converters to simultaneously collect multi-phase electrical parameters by sending a chip select signal and a clock signal to each analog-to-digital converter. The plurality of analog-to-digital converters can be respectively connected to the electrical parameter measurement points of different phases, so that the data of the multi-phase electrical parameters can be obtained at the same time, the measurement range is expanded, and the limitation of measuring only single-phase electrical parameters is avoided. The chip select signal and the clock signal are sent to each analog-to-digital converter at the same time, so that the effective management of the plurality of analog-to-digital converters can be realized. This is equivalent to increasing the number of sampling channels, so that the plurality of signal sources or the plurality of different parameters of the same signal source can be sampled at the same time, thereby solving the problem of a small number of sampling channels.

[0016] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 is a structural schematic diagram of an electrical parameter measuring device provided by an embodiment of the present invention;

[0019] Figure 2 is a structural schematic diagram of a zero-crossing detection module provided by an embodiment of the present invention;

[0020] Figure 3 is a structural schematic diagram of another electrical parameter measuring device provided by an embodiment of the present invention;

[0021] Figure 4 is a structural schematic diagram of another electrical parameter measuring device provided by an embodiment of the present invention;

[0022] Figure 5 is a structural schematic diagram of another electrical parameter measuring device provided by an embodiment of the present invention;

[0023] Figure 6 It is a structural schematic diagram of a DC power conversion module provided by an embodiment of the present invention;

[0024] Figure 7 is a structural schematic diagram of a power supply monitoring module provided by an embodiment of the present invention;

[0025] Figure 8 This is a structural diagram of another electrical parameter measurement device provided by an embodiment of the present invention.

[0026] Fig. 9 is a structural diagram of a communication module provided by an embodiment of the present invention;

[0027] Fig.10 It is a structural schematic diagram of another electrical parameter measurement device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0030] Figure 1 FIG. 1 is a schematic diagram of the structure of an electrical parameter measurement device provided by an embodiment of the present invention. Figure 1 As shown, the electrical parameter measuring device includes: a zero-crossing detection module 11 , a control module 12 and a plurality of analog-to-digital converters 13 .

[0031] The input end of the zero-crossing detection module 11 is connected to the AC signal AC, and the output end of the zero-crossing detection module 11 is connected to the first input end IN1 of the control module 12, which is used to convert the AC signal AC into a DC square wave signal of the same frequency and input it into the control module 12; the control module 12 is used to measure the period of the DC square wave signal and determine the frequency of the AC signal AC according to the period of the DC square wave signal.

[0032] Multiple analog-to-digital converters 13 are connected in a daisy-chain manner, and the second input terminal IN2 of the control module 12 is connected to the data output terminal of the last analog-to-digital converter 13 in the daisy-chain. The control module 12 is also used to send a chip select signal and a clock signal to each analog-to-digital converter 13 to control the multiple analog-to-digital converters 13 to simultaneously collect multi-phase electrical parameters according to the chip select signal and the clock signal. Figure 1 The case where the electrical parameter measuring device includes four analog-to-digital (AD) converters 13 is schematically shown.

[0033] Specifically, an AC signal AC refers to an electrical signal whose magnitude and direction change periodically over time. Exemplarily, an AC signal may be a sinusoidal AC signal. A DC square wave signal is a DC signal whose level periodically switches between a high level and a low level.

[0034] The zero-crossing detection module 11 converts the AC signal into a DC square wave signal of the same frequency and then inputs it into the control module 12. The control module 12 determines the frequency of the AC signal by measuring the period of the DC square wave signal and based on the inverse relationship between frequency and period.

[0035] The control module 12 may include a microcontroller. Optionally, the control module 12 may include a single chip microcomputer, a digital signal processor (DSP) or a field programmable gate array (FPGA). For example, the control module 12 may use a DSP, model FDM320R335, which has strong computing power.

[0036] The analog-to-digital converter 13 is an electronic component that converts an analog signal into a digital signal. In this system, multiple analog-to-digital converters 13 are connected in a daisy chain to simultaneously collect multi-phase electrical parameters. The so-called "multi-phase electrical parameters" refer to the electrical parameters such as voltage and current that may exist in multiple phases (such as phase A, phase B, and phase C in a three-phase AC system) in the power system. The daisy chain connection method is a connection method that connects multiple devices in series, and data is transmitted between devices in sequence.

[0037] Continue to refer Figure 1 , the working process of the electrical parameter measuring device is:

[0038] The AC signal AC first enters the zero-crossing detection module 11. The zero-crossing detection module 11 detects the zero-crossing point of the AC signal through components such as comparators. When the voltage of the AC signal is higher than the first reference voltage, a high level is output; when the voltage of the AC signal is lower than the first reference voltage, a low level is output. In this way, the AC signal is converted into a DC square wave signal of the same frequency. This DC square wave signal is sent to the first input terminal IN1 of the control module 12. The control module 12 determines the frequency of the AC signal AC by measuring the period of the DC square wave signal. For example, if the period of the DC square wave signal is 0.02 seconds, according to the frequency calculation formula f=1 / T (where f is the frequency and T is the period), the frequency of the AC signal can be calculated to be 50Hz.

[0039] The plurality of analog-to-digital converters 13 are connected in a daisy chain. The second input terminal IN2 of the control module 12 is connected to the data output terminal of the last analog-to-digital converter 13 in the daisy chain.

[0040] The control module 12 sends a chip select signal and a clock signal to each analog-to-digital converter 13. The chip select signal is used to select a specific analog-to-digital converter to operate, and the clock signal is used to synchronize the work of the analog-to-digital converter. Under the control of these signals, multiple analog-to-digital converters 13 can collect multi-phase electrical parameters at the same time. For example, in a three-phase electrical system, three analog-to-digital converters 13 can be connected to the electrical parameter measurement points of phase A, phase B and phase C respectively, and the analog electrical parameter signals are converted into digital signals at the same time, which can be further processed and analyzed by the control module 12 to obtain relevant information of the multi-phase electrical parameters. For example, the control module 12 can calculate the collected multi-phase electrical parameter data, obtain the values ​​of relevant electrical parameters such as power and power factor of the three-phase electricity, or store the data for subsequent viewing and analysis.

[0041] The electrical parameter measuring device of the embodiment of the present invention is provided with a zero-crossing detection module, which can convert the connected AC signal into a DC square wave signal of the same frequency. The control module measures the period of the DC square wave signal, and then determines the frequency of the AC signal, thereby realizing the measurement of the frequency of the AC signal. A plurality of analog-to-digital converters are daisy-chained. This connection mode enables the control module to control the plurality of analog-to-digital converters to simultaneously collect multi-phase electrical parameters by sending a chip select signal and a clock signal to each analog-to-digital converter. The plurality of analog-to-digital converters can be respectively connected to the electrical parameter measurement points of different phases, so that the data of the multi-phase electrical parameters can be obtained at the same time, the measurement range is expanded, and the limitation of measuring only single-phase electrical parameters is avoided. The chip select signal and the clock signal are sent to each analog-to-digital converter at the same time, so that the effective management of the plurality of analog-to-digital converters can be realized. This is equivalent to increasing the number of sampling channels, so that the plurality of signal sources or the plurality of different parameters of the same signal source can be sampled at the same time, thereby solving the problem of a small number of sampling channels.

[0042] Optionally, continue to refer to Figure 1 The electrical parameter measuring device also includes a signal processing module 14, which is connected to the analog-to-digital converter 13 in a one-to-one correspondence and is used to amplify the target signal and filter it. The target signal can be a voltage signal, a current signal, or other electrical signals. In some embodiments, the signal processing module 14 includes a low-pass filter circuit and an operational amplifier circuit, which are used to filter out high-frequency interference signals in the target signal and convert them into signals suitable for the measurement range of the AD converter 12.

[0043] Figure 2 Schematic diagram of a zero-crossing detection module provided by an embodiment of the present invention. Figure 2 As shown, optionally, the zero-crossing detection module 11 includes a comparator U1 , a first resistor R1 , a second resistor R2 , a third resistor R3 and a first capacitor C1 .

[0044] The first end of the first resistor R1 is used as the input end of the zero-crossing detection module 11, and the second end of the first resistor R1 is connected to the non-inverting input end of the comparator U1. The first end of the second resistor R2 is connected to the first reference voltage Vref1, and the second end of the second resistor R2 is connected to the inverting input end of the comparator U1.

[0045] A first end of the third resistor R3 is connected to the comparison output end of the comparator U1 and serves as the output end of the zero-crossing detection module 11, and a second end of the third resistor R3 is grounded; a first end of the first capacitor C1 is connected to the first power supply end of the comparator U1 and is connected to the first voltage V1, a second end of the first capacitor C1 is grounded, and a second power supply end of the comparator U1 is grounded; the comparator U1 is used to output a first level signal through the comparison output end when the voltage of the alternating current signal AC is greater than the first reference voltage Vref1; and output a second level signal through the comparison output end when the voltage of the alternating current signal AC is less than the first reference voltage Vref1, wherein the first level signal and the second level signal are signals with opposite high and low levels.

[0046] Specifically, the first end of the first resistor R1 is used as the input end of the zero-crossing detection module 11 for receiving the AC signal AC. The second end thereof is connected to the non-inverting input end of the comparator U1. The first resistor R1 plays a current limiting role to prevent the excessive current that may exist in the AC signal AC from damaging the non-inverting input end of the comparator U1. For example, if there is no first resistor R1, when the amplitude of the AC signal AC is large, a large current may be generated, resulting in damage to components such as the input stage transistor of the comparator U1.

[0047] The first end of the second resistor R2 is connected to the first reference voltage Vref1, and the second end of the second resistor R2 is connected to the inverting input terminal of the comparator U1. The second resistor R2 and the first reference voltage Vref1 together constitute a reference voltage setting circuit of the comparator U1. The first reference voltage Vref1 is a fixed DC voltage, and the second resistor R2 is used to adjust the reference voltage input to the inverting input terminal of the comparator U1. This reference voltage is the reference for the comparator U1 to judge the level of the AC signal AC.

[0048] The first end of the third resistor R3 is connected to the comparison output end of the comparator U1, and this end serves as the output end of the zero-crossing detection module 11. The second end of the third resistor R3 is grounded. The third resistor R3 is used to limit the current output by the comparator U1 to prevent the subsequent circuit from being damaged due to excessive current. When the output level of the comparator U1 changes, the third resistor R3 can limit the sudden change of the output current and play a protective role.

[0049] The first end of the first capacitor C1 is connected to the first power supply end of the comparator U1 and connected to the first voltage V1, and the second end is grounded. The first capacitor C1 plays a filtering role, which can filter out high-frequency clutter in the first voltage V1, so that the power supply voltage of the comparator U1 is more stable. A stable power supply voltage is very important for the normal operation of the comparator U1, and can reduce the comparator output error caused by power supply fluctuations. Exemplarily, the first voltage V1 can be 3.3V.

[0050] When the voltage of the AC signal AC is greater than the first reference voltage Vref1, the voltage of the non-inverting input terminal of the comparator U1 is higher than the voltage of the inverting input terminal. According to the working characteristics of the comparator U1, the comparator U1 outputs a first level signal (eg, high level) through the comparison output terminal.

[0051] When the voltage of the AC signal AC is less than the first reference voltage Vref1, the voltage of the non-inverting input terminal of the comparator U1 is lower than the voltage of the inverting input terminal, and the comparator U1 outputs a second level signal (e.g., a low level) through the comparison output terminal. Since the AC signal AC changes periodically, its voltage will constantly alternate between being greater than and less than the reference voltage Vref1, so the output level of the comparator U1 will also periodically alternate between a high level and a low level accordingly, thereby converting the AC signal AC into a DC square wave signal of the same frequency and outputting it from the comparison output terminal.

[0052] Alternatively, comparator U1 may be a LM393 comparator.

[0053] Figure 3 FIG. 1 is a schematic diagram of the structure of another electrical parameter measuring device provided by an embodiment of the present invention. Figure 3 As shown, optionally, the analog-to-digital converter 13 includes an analog-to-digital conversion chip U2, a second capacitor C2, a third capacitor C3, a fourth capacitor C4 and a magnetic bead F1.

[0054] The first end of the second capacitor C2 is connected to the reference voltage pin REF of the analog-to-digital conversion chip U2, and is connected to the second reference voltage Vref2, and the second end of the second capacitor C2 is grounded. The first end of the third capacitor C3 is grounded, and the second end of the third capacitor C3 is connected to the analog power pin AVDD of the analog-to-digital conversion chip U2, and is connected to the second voltage V2. The first end of the fourth capacitor C4 is grounded, and the second end of the fourth capacitor C4 is respectively connected to the first end of the magnetic bead F1 and the digital power pin DVDD of the analog-to-digital conversion chip U2; the second end of the magnetic bead F1 is connected to the second voltage V2. The serial clock pin SCLK of the analog-to-digital conversion chip U2 is connected to the clock signal CLK, and the conversion start pin CONVST of the analog-to-digital conversion chip U2 is connected to the chip select signal CNV. The first analog input pin AINP and the second analog input pin AINN of the analog-to-digital conversion chip U2 are connected to the signal processing module 14.

[0055] Specifically, the data output pin DOUT of the analog-to-digital conversion chip U2 serves as the data output terminal of the analog-to-digital converter 13. Exemplarily, the electrical parameter measuring device includes N analog-to-digital converters 13, that is, includes N analog-to-digital conversion chips U2, each analog-to-digital conversion chip U2 is cascaded in a daisy chain manner, the data input pin DIN of the first analog-to-digital conversion chip U2 cascaded in a daisy chain manner is grounded, the data output pin DOUT of the i-th analog-to-digital conversion chip U2 cascaded in a daisy chain manner is connected to the data output pin DOUT of the i+1-th analog-to-digital conversion chip U2 cascaded in a daisy chain manner, and the data output pin DOUT of the last analog-to-digital conversion chip U2 cascaded in a daisy chain manner is connected to the second input terminal IN2 of the control module 12. i is an integer greater than or equal to 1 and less than N. The ground pin GND of the analog-to-digital conversion chip U2 is grounded.

[0056] Exemplarily, the analog-to-digital (AD) conversion chip U2 can be TPC5160, which has a sampling accuracy of 16 bits and a sampling rate of 600kSPS, which meets the development of electrical test instruments. The cascade mode of multiple AD converters is a daisy chain mode, the 8th pin is the clock signal input pin of the chip, and the 6th pin is the chip select signal input pin of the chip. The clock signal and the chip select signal are both output by the control module 12. Because the clock signal and the chip select signal of multiple AD converters 13 are the same signal, the simultaneity of the sampling of the AD converter 13 is guaranteed. Because the AD converter cascade mode adopts the daisy chain mode, the expansion of the AD converter 13 is convenient.

[0057] Figure 4 FIG. 1 is a schematic diagram of the structure of another electrical parameter measuring device provided by an embodiment of the present invention. Figure 4 As shown, optionally, the electrical parameter measurement module also includes a GPS module 15, which is used to receive a timing signal sent by a satellite and generate a second pulse signal according to the timing signal; the control module 12 is used to determine the phase of the alternating current signal AC according to the second pulse signal.

[0058] Specifically, a timing signal is a signal containing precise time information. It is generated by a high-precision time source (such as an atomic clock) and transmitted through a specific method (such as satellite communication, terrestrial broadcasting, etc.) in order to provide an accurate time reference for the receiving device.

[0059] The GPS module 15 includes a high-precision clock circuit and a counter. After receiving the satellite timing signal and determining the starting time point, the clock circuit will count at an accurate frequency. Whenever the count reaches a specific value (this value is set according to the clock frequency and a time period of 1 second), a pulse will be generated to form a second pulse signal. For example, if the clock frequency is 10MHz, there will be 10,000,000 clock cycles in 1 second, and through appropriate counting settings, a pulse can be generated every 1 second. The second pulse signal is a periodic pulse signal with a period of exactly 1 second.

[0060] When the control module 12 receives the pulse per second signal, it can use the signal as a time reference point, marking it as time t=0 (or construct an accurate time coordinate system based on it).

[0061] The control module 12 is also monitoring the AC signal AC. Assuming that the frequency of the AC signal AC is f (known quantity), and its period T=1 / f. By measuring the time interval Δt from the pulse-per-second signal (as the starting time reference) to the next specific point of the AC signal (such as the positive peak value, zero crossing point, etc.), the phase of the AC signal AC can be calculated.

[0062] Taking a sinusoidal AC signal as an example, its phase (in radians) can be calculated using the formula For example, if the frequency of the sinusoidal AC signal is f = 50 Hz, then the period of the sinusoidal AC signal is T = 0.02 seconds. If the time interval from the start of the second pulse signal to the positive peak of the sinusoidal AC signal is Δt = 0.005 seconds, then the phase can be calculated according to the formula Radians (or angles equal to 90°)

[0063] In some embodiments, the GPS module 15 can also be used to calibrate the accuracy of the internal timer of the control module 12 .

[0064] Figure 5 FIG. 1 is a schematic diagram of the structure of another electrical parameter measuring device provided by an embodiment of the present invention. Figure 5 As shown, optionally, the electrical parameter measuring device further includes a DC power conversion module 16, which is used to convert the third voltage V3 into a first voltage V1 to power the zero-crossing detection module 11, the control module 12 and the plurality of analog-to-digital converters 13; wherein the third voltage V3 is greater than the first voltage V1. Exemplarily, the third voltage V3 is 5V and the first voltage V1 is 3.3V.

[0065] As an optional implementation provided in this embodiment, Figure 6 is a schematic diagram of a DC power conversion module provided by an embodiment of the present invention, combined with Figure 5 and Figure 6 Optionally, the DC power conversion module 16 includes a step-down chip U3, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a first inductor L1.

[0066] The first end of the fifth capacitor C5 is connected to the input pin IN of the buck chip U3, and is connected to the third voltage V3, and the second end of the fifth capacitor C5 is grounded. The sixth capacitor C6 is connected in parallel with the fifth capacitor C5. The first end of the seventh capacitor C7 is connected to the bootstrap pin BS of the buck chip U3, and the second end of the seventh capacitor C7 is connected to the first end of the first inductor L1. The first end of the eighth capacitor C8 is connected to the second end of the first inductor L1 and the switch pin LX of the buck chip U3, and is connected to the first voltage V1, and the second end of the eighth capacitor C8 is grounded. The first end of the fourth resistor R4 is connected to the input pin IN of the buck chip U3, and the second end of the fourth resistor R4 is connected to the enable pin EN of the buck chip U3. The first end of the fifth resistor R5 is connected to the feedback pin FB of the buck chip U3, and the second end of the fifth resistor R5 is grounded. The first end of the sixth resistor R6 is connected to the first end of the fifth resistor R5, the second end of the sixth resistor R6 is connected to the second end of the first inductor L1, and the ninth capacitor C9 is connected in parallel with the sixth resistor R6.

[0067] Exemplarily, the buck chip U3 may be SY8113C1ADC, which steps down the third voltage V3 (eg, 5V) to the first voltage V1 (eg, 3.3V) to power the zero-crossing detection module 11, the control module 12, and the multiple analog-to-digital converters 13. The ground pin GND1 of the buck chip U3 is grounded.

[0068] Continue to refer Figure 5 Optionally, the electrical parameter measuring device also includes a power monitoring module 17, which is connected to the control module 12 and the DC power conversion module 16 respectively, and is used to monitor whether the first voltage V1 is normal. When the first voltage V1 is abnormal, the control module 12 is reset.

[0069] Specifically, the power supply monitoring module 17 will compare the first voltage V1 actually monitored with the preset voltage range. The preset voltage range is determined according to the working voltage requirements of the zero-crossing detection module 11, the control module 12 and the analog-to-digital converter 13. For example, the preset voltage range is 3.0V-3.6V. When the first voltage V1 exceeds the preset voltage range, it is determined to be a voltage abnormality. The voltage abnormality may be caused by a variety of reasons, such as the failure of the DC power conversion module 16 causing the output voltage to be too high or too low, the sudden change of the system load causing the voltage fluctuation to be too large, etc. The control module 12 is the core control unit of the entire electrical parameter measurement device. When the first voltage V1 is abnormal, the control module 12 may have an abnormal operation, such as a program runaway (the program counter is wrong, resulting in a disordered program execution order), data processing errors, etc. In order to prevent these abnormal conditions from causing more serious problems in the system, such as wrong measurement data, equipment damage, etc., it is necessary to reset the control module 12.

[0070] When the power monitoring module 17 detects that the first voltage V1 is abnormal, it sends a reset signal to the control module 12. The reset signal restores the circuit inside the control module 12 to the initial state, such as resetting the program counter and clearing the register. After the control module 12 is restarted, it will start running again according to the preset program flow, so that it is possible to resume normal operation, and recheck whether the voltage has returned to normal, and continue to perform operations such as measuring electrical parameters.

[0071] Figure 7 Schematic diagram of a power supply monitoring module provided by an embodiment of the present invention. Figure 7 As shown, optionally, the power monitoring module 17 includes a power monitoring chip U4, a tenth capacitor C10 and a seventh resistor R7.

[0072] The first end of the tenth capacitor C10 is connected to the power pin VCC of the power monitoring chip U4 and is connected to the first voltage V1. The second end of the tenth capacitor C10 is grounded. The first end of the seventh resistor R7 is connected to the reset output pin VCC of the power monitoring chip U4. The second end of the seventh resistor R7 is connected to the first voltage V1. The ground pin GND2 of the power monitoring chip U4 is grounded.

[0073] Optionally, the power monitoring chip U4 can use SGM809. When the voltage value monitored by the chip is lower than 2.63V, the second pin of the chip (i.e., the reset output pin) ) sends a reset signal to reset the control module 12.

[0074] Figure 8 FIG. 1 is a schematic diagram of the structure of another electrical parameter measuring device provided by an embodiment of the present invention. Figure 8As shown, the electrical parameter measurement module further includes a communication module 18, which is communicatively connected to the control module 12 and is used for enabling the control module 12 to communicate with a host computer.

[0075] Fig. 9 Schematic diagram of a communication module provided by an embodiment of the present invention. Fig. 9 As shown, the communication module 18 includes a CAN transceiver chip U5, an eleventh capacitor C11, a twelfth capacitor C12, an eighth resistor R8, a first transient voltage suppression diode TVS1 and a second transient voltage suppression diode TVS2.

[0076] The first end of the eleventh capacitor C11 is connected to the first power supply pin VCC1 of the CAN transceiver chip U5, and is connected to the first voltage V1, and the second end of the eleventh capacitor C11 is grounded. The first end of the twelfth capacitor C12 is connected to the second power supply pin VCC2 of the CAN transceiver chip U5, and is connected to the third voltage V3, and the second end of the twelfth capacitor C12 is grounded. The first end of the eighth resistor R8 is connected to the first differential signal input and output pin CANH of the CAN transceiver chip U5, and the second end of the eighth resistor R8 is connected to the second differential signal input and output pin CANL of the CAN transceiver chip U5. The first transient voltage suppression diode TVS1 is connected in parallel with the eighth resistor R8. The first end of the second transient voltage suppression diode TVS2 is connected to the first end of the eighth resistor R8, the second end of the second transient voltage suppression diode TVS2 is connected to the second end of the eighth resistor R8, and the third end of the second transient voltage suppression diode TVS2 is grounded. The transmit data input pin TXD and the receive data output pin RXD of the CAN transceiver chip U5 are both connected to the control module 12. The first ground pin GND3 and the second ground pin GND4 of the CAN transceiver chip U5 are both grounded.

[0077] Optionally, the CAN transceiver chip U5 may adopt CA-IS3050G, which is an isolated CAN communication chip, and isolates the electrical parameter measurement device from the host computer, thereby ensuring the safety of the host computer.

[0078] Fig.10 FIG. 1 is a schematic diagram of the structure of another electrical parameter measuring device provided by an embodiment of the present invention. Fig.10 As shown, the electrical parameter measuring device includes a zero-crossing detection module 11 , a control module 12 and a plurality of analog-to-digital converters 13 .

[0079] Optionally, the electrical parameter measurement module further includes a GPS module 15 , a DC power conversion module 16 , a power monitoring module 17 and a communication module 18 .

[0080] Optionally, the electrical parameter measurement module also includes a reserved interface 19, which includes at least a serial peripheral interface (Serial Peripheral Interface, SPI), an I2C (Inter-Integrated Circuit) interface, a USB (Universal Serial Bus) interface, a CAN and an asynchronous receiver / transmitter (Universal Asynchronous Receiver / Transmitter, UART) interface. The reserved interface is used to communicate with some sensors, such as ranging sensors and speed sensors, and can also be used to communicate with other microprocessors.

[0081] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An electrical parameter measuring device, characterized in that: include: A zero-crossing detection module, a control module and a plurality of analog-to-digital converters; The input end of the zero-crossing detection module is connected to an AC signal, and the output end of the zero-crossing detection module is connected to the first input end of the control module, so as to convert the AC signal into a DC square wave signal of the same frequency and input it into the control module; the control module is used to measure the period of the DC square wave signal, and determine the frequency of the AC signal according to the period of the DC square wave signal; Multiple analog-to-digital converters are connected in a daisy-chain manner, and the second input end of the control module is connected to the data output end of the last analog-to-digital converter in the daisy-chain. The control module is also used to send a chip select signal and a clock signal to each analog-to-digital converter to control the multiple analog-to-digital converters to simultaneously collect multi-phase electrical parameters according to the chip select signal and the clock signal.

2. The electrical parameter measuring device according to claim 1, characterized in that: The zero-crossing detection module includes a comparator, a first resistor, a second resistor, a third resistor and a first capacitor; The first end of the first resistor is used as the input end of the zero-crossing detection module, and the second end of the first resistor is connected to the non-inverting input end of the comparator; A first end of the second resistor is connected to a first reference voltage, and a second end of the second resistor is connected to an inverting input end of the comparator; The first end of the third resistor is connected to the comparison output end of the comparator and serves as the output end of the zero-crossing detection module, and the second end of the third resistor is grounded; The first end of the first capacitor is connected to the first power supply end of the comparator and is connected to a first voltage, the second end of the first capacitor is grounded, and the second power supply end of the comparator is grounded; The comparator is used for outputting a first level signal through the comparison output terminal when the voltage of the AC signal is greater than the first reference voltage; And when the voltage of the AC signal is less than the first reference voltage, a second level signal is output through the comparison output terminal, wherein the first level signal and the second level signal are signals with opposite high and low levels.

3. The electrical parameter measuring device according to claim 1, characterized in that: The analog-to-digital converter includes an analog-to-digital conversion chip, a second capacitor, a third capacitor, a fourth capacitor and a magnetic bead; A first end of the second capacitor is connected to a reference voltage pin of the analog-to-digital conversion chip and is connected to a second reference voltage, and a second end of the second capacitor is grounded; A first end of the third capacitor is grounded, and a second end of the third capacitor is connected to an analog power pin of the analog-to-digital conversion chip and is connected to a second voltage; The first end of the fourth capacitor is grounded, and the second end of the fourth capacitor is respectively connected to the first end of the magnetic bead and the digital power pin of the analog-to-digital conversion chip; the second end of the magnetic bead is connected to the second voltage; The serial clock pin of the analog-to-digital conversion chip is connected to the clock signal, and the conversion start pin of the analog-to-digital conversion chip is connected to the chip selection signal.

4. The electrical parameter measuring device according to claim 1, characterized in that: It also includes a GPS module, which is used to receive a timing signal sent by a satellite and generate a second pulse signal according to the timing signal; The control module is used to determine the phase of the AC signal according to the pulse per second signal.

5. The electrical parameter measuring device according to claim 1, characterized in that: It also includes a DC power conversion module, which is used to convert the third voltage into a first voltage to power the zero-crossing detection module, the control module and the multiple analog-to-digital converters; wherein the third voltage is greater than the first voltage.

6. The electrical parameter measuring device according to claim 5, characterized in that: The DC power conversion module includes a step-down chip, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a fourth resistor, a fifth resistor, a sixth resistor and a first inductor; A first end of the fifth capacitor is connected to an input pin of the buck chip and connected to the third voltage, and a second end of the fifth capacitor is grounded; The sixth capacitor is connected in parallel with the fifth capacitor; A first end of the seventh capacitor is connected to the bootstrap pin of the buck chip, and a second end of the seventh capacitor is connected to the first end of the first inductor; A first end of the eighth capacitor is connected to the second end of the first inductor and the switch pin of the buck chip and connected to the first voltage, and a second end of the eighth capacitor is grounded; A first end of the fourth resistor is connected to an input pin of the buck chip, and a second end of the fourth resistor is connected to an enable pin of the buck chip; A first end of the fifth resistor is connected to a feedback pin of the buck chip, and a second end of the fifth resistor is grounded; The first end of the sixth resistor is connected to the first end of the fifth resistor, the second end of the sixth resistor is connected to the second end of the first inductor, and the ninth capacitor is connected in parallel to the sixth resistor.

7. The electrical parameter measuring device according to claim 5, characterized in that: It also includes a power monitoring module, which is connected to the control module and the DC power conversion module respectively, and is used to monitor whether the first voltage is normal. When the first voltage is abnormal, the control module is reset.

8. The electrical parameter measuring device according to claim 7, characterized in that: The power monitoring module includes a power monitoring chip, a tenth capacitor and a seventh resistor; A first end of the tenth capacitor is connected to a power pin of the power monitoring chip and is connected to a first voltage, and a second end of the tenth capacitor is grounded; The first end of the seventh resistor is connected to the reset output pin of the power monitoring chip, and the second end of the seventh resistor is connected to the first voltage.

9. The electrical parameter measuring device according to claim 1, characterized in that: It also includes a communication module, which is communicatively connected to the control module and is used for the control module to communicate with a host computer.

10. The electrical parameter measuring device according to claim 9, characterized in that: The communication module includes a CAN transceiver chip, an eleventh capacitor, a twelfth capacitor, an eighth resistor, a first transient voltage suppression diode and a second transient voltage suppression diode; The first end of the eleventh capacitor is connected to the first power supply pin of the CAN transceiver chip and is connected to a first voltage, and the second end of the eleventh capacitor is grounded; The first end of the twelfth capacitor is connected to the second power supply pin of the CAN transceiver chip and is connected to a third voltage, and the second end of the twelfth capacitor is grounded; A first end of the eighth resistor is connected to a first differential signal input / output pin of the CAN transceiver chip, and a second end of the eighth resistor is connected to a second differential signal input / output pin of the CAN transceiver chip; The first transient voltage suppression diode is connected in parallel with the eighth resistor; The first end of the second transient voltage suppression diode is connected to the first end of the eighth resistor, the second end of the second transient voltage suppression diode is connected to the second end of the eighth resistor, and the third end of the second transient voltage suppression diode is grounded; The sending data input pin and receiving data output pin of the CAN transceiver chip are both connected to the control module.

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