Electronic voltage transformer and control method thereof

Abstract

The application discloses an electronic voltage transformer and a control method thereof, and relates to the technical field of electronic voltage transformers, and specifically discloses the electronic voltage transformer, which comprises a direct-current signal conditioning circuit, an alternating-current signal conditioning circuit, a sampling analysis module, and a first voltage division branch and a second voltage division branch connected in parallel, wherein the third end of the first voltage division branch is electrically connected with the direct-current signal conditioning circuit, the direct-current signal conditioning circuit is electrically connected with the sampling analysis module, the third end of the second voltage division branch is electrically connected with the alternating-current signal conditioning circuit, and the alternating-current signal conditioning circuit is electrically connected with the sampling analysis module. In the embodiment, the first voltage division branch and the second voltage division branch are used to reduce the to-be-input voltage into a small voltage for subsequent module processing. Voltage type recognition is performed on the amplitude signal and the frequency signal generated by the sampling analysis module, and the amplitude signal is converted into a matching signal for output. In the embodiment, the to-be-input voltage can be a direct-current voltage or an alternating-current voltage, the applicability of the electronic voltage transformer is improved, and the structure is simple.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mutual inductor, and particularly to an electronic voltage transformer and a control method thereof. BACKGROUND

[0002] The rail transit traction system in China is divided into AC traction power supply and DC traction power supply system, and the electrified railway generally adopts AC traction system, and the urban rail transit generally adopts DC traction system, and in both systems, voltage transformers are needed for measurement of power supply system, measurement of electric energy, and measurement of frequency and power.

[0003] The existing problems in the industry are that the existing voltage transformers cannot be commonly used in DC and AC power supply systems. SUMMARY

[0004] The present application provides an electronic voltage transformer and a control method thereof to automatically identify the type of input voltage and output.

[0005] The present application provides an electronic voltage transformer and a control method thereof to automatically identify the type of input voltage and output.

[0006] The first end of the first voltage dividing branch is electrically connected to the first end of the second voltage dividing branch, the second end of the first voltage dividing branch is electrically connected to the second end of the second voltage dividing branch, the first end of the first voltage dividing branch is connected to the input voltage, the second end of the first voltage dividing branch is grounded, the third end of the first voltage dividing branch is electrically connected to the input end of the DC signal conditioning circuit, the output end of the DC signal conditioning circuit is electrically connected to the first input end of the sampling analysis module, the third end of the second voltage dividing branch is electrically connected to the input end of the AC signal conditioning circuit, the output end of the AC signal conditioning circuit is electrically connected to the second input end of the sampling analysis module, and the output end of the sampling analysis module is electrically connected to the measuring instrument; the resistance values of the first voltage dividing branch and the second voltage dividing branch are different, so that the voltage applied to the first voltage dividing branch and the second voltage dividing branch is the same, and the voltage values output by the first output end and the second output end are different.

[0007] The first voltage dividing branch is configured to transmit the to-be-input voltage after being reduced to the direct current signal conditioning circuit, and the second voltage dividing branch is configured to transmit the to-be-input voltage after being reduced to the alternating current signal conditioning circuit; the direct current signal conditioning circuit is configured to generate a first voltage signal after filtering out interference signals in the to-be-input voltage, and the alternating current signal conditioning circuit is configured to generate a second voltage signal after filtering out direct current signals and interference signals in the to-be-input voltage; the sampling and analysis module is configured to generate an amplitude signal after sampling the first voltage signal and generate a frequency signal after sampling the second voltage signal, and is further configured to identify a voltage type according to the amplitude signal and the frequency signal, and convert the amplitude signal into a matching signal output, the matching signal being a voltage signal or a current signal matched with the measuring instrument, and the voltage type including a direct current voltage and an alternating current voltage.

[0008] Optionally, the first voltage dividing branch includes a first resistor and a second resistor, a first end of the first resistor serving as a first end of the first voltage dividing branch, a second end of the first resistor being electrically connected with a first end of the second resistor, the second end of the first resistor serving as a third end of the first voltage dividing branch, and a second end of the second resistor serving as a second end of the first voltage dividing branch.

[0009] The second voltage dividing branch includes a third resistor and a fourth resistor, a first end of the third resistor serving as a first end of the second voltage dividing branch, a second end of the third resistor being electrically connected with a first end of the fourth resistor, the second end of the third resistor serving as a third end of the second voltage dividing branch, and a second end of the fourth resistor serving as a second end of the second voltage dividing branch.

[0010] Optionally, the direct current signal conditioning circuit includes a voltage stabilizer, a current limiting protection unit, a first filter resistor and a first filter capacitor, a first end of the voltage stabilizer being electrically connected with the third end of the first voltage dividing branch, the first end of the voltage stabilizer also being electrically connected with an input end of the current limiting protection unit, an output end of the current limiting protection unit being electrically connected with a first end of the first filter resistor, a second end of the first filter resistor being electrically connected with a first end of the first filter capacitor, a second end of the first filter capacitor being grounded, and the second end of the first filter resistor being electrically connected with a first input end of the sampling and analysis module.

[0011] Optionally, the alternating current signal conditioning circuit includes a first direct-current blocking capacitor, a second direct-current blocking capacitor, a voltage follower, an analog-to-digital conversion unit, a second filter resistor and a second filter capacitor.

[0012] The first end of the first DC blocking capacitor is electrically connected with the third end of the second voltage division branch, the second end of the first DC blocking capacitor is electrically connected with the first end of the second DC blocking capacitor, the second end of the second DC blocking capacitor is electrically connected with the first end of the second filter resistor, the second end of the second filter resistor is electrically connected with the first end of the second filter capacitor, the second end of the second filter resistor is also electrically connected with the input end of the voltage follower, the output end of the voltage follower is electrically connected with the input end of the analog-digital conversion unit, and the output end of the analog-digital conversion unit is electrically connected with the second input end of the sampling analysis module.

[0013] Optionally, the sampling analysis module comprises a first sampling circuit, a second sampling circuit, a controller and an output module; the input end of the first sampling circuit is electrically connected with the output end of the DC signal conditioning circuit, the output end of the first sampling circuit is electrically connected with the first end of the controller, the input end of the second sampling circuit is electrically connected with the output end of the AC signal conditioning circuit, the output end of the second sampling circuit is electrically connected with the second end of the controller, the output end of the controller is electrically connected with the input end of the output module, and the output end of the output module is electrically connected with the measuring instrument; the controller is configured to generate the amplitude signal according to the first voltage signal, generate the frequency signal according to the second voltage signal, and perform voltage type identification according to the amplitude signal and the frequency signal; and the output module is configured to convert the amplitude signal into a matching signal.

[0014] Optionally, the electronic voltage transformer further comprises a first indication module and a second indication module, the first indication module is electrically connected with the sampling analysis module, the second indication module is electrically connected with the sampling analysis module, the sampling analysis module is configured to control the second indication module to be turned on when the voltage type identification result is AC voltage, and control the first indication module to be turned on when the voltage type identification result is DC voltage.

[0015] Another aspect of the present application provides a control method of an electronic voltage transformer, which is used for controlling the electronic voltage transformer of any one of the preceding aspects, and the electronic voltage transformer comprises a first voltage division branch, a second voltage division branch, a DC signal conditioning circuit, an AC signal conditioning circuit and a sampling analysis module; the control method of the electronic voltage transformer comprises the following steps:

[0016] The first voltage division branch transmits the voltage to be input after being reduced to the DC signal conditioning circuit, and the second voltage division branch transmits the voltage to be input after being reduced to the AC signal conditioning circuit.

[0017] The direct current signal conditioning circuit generates a first voltage signal after filtering out interference signals in the to-be-input voltage, and the alternating current signal conditioning circuit generates a second voltage signal after filtering out direct current signals and interference signals in the to-be-input voltage;

[0018] The sampling analysis module generates an amplitude signal after sampling the first voltage signal and generates a frequency signal after sampling the second voltage signal, performs voltage type identification according to the amplitude signal and the frequency signal, and converts the amplitude signal into a matching signal output, the matching signal being a voltage signal or a current signal matched with a measuring instrument, and the voltage type including direct current voltage and alternating current voltage.

[0019] Optionally, the voltage type identification performed by the sampling analysis module according to the amplitude signal and the frequency signal includes:

[0020] If the frequency signal meets a first frequency setting range and the amplitude signal meets a first setting condition, it is determined that the type of the input signal in the electronic voltage transformer is an alternating current signal.

[0021] If the frequency signal meets a second frequency setting range and the amplitude signal meets a second setting condition, it is determined that the type of the input signal in the electronic voltage transformer is a direct current signal, and each frequency in the first frequency setting range is greater than each frequency in the second frequency setting range.

[0022] Optionally, the sampling analysis module generates an amplitude signal after sampling the first voltage signal and generates a frequency signal after sampling the second voltage signal, and the method includes:

[0023] The second voltage signal is sampled and then subjected to Fourier transform to generate a frequency domain signal, and the frequency signal is obtained according to the frequency domain signal.

[0024] The first voltage signal is sampled and then subjected to calculation according to a setting method to generate an amplitude signal.

[0025] Optionally, the first voltage signal is calculated according to a setting method to generate an amplitude signal, and the method includes:

[0026] The maximum amplitude and the minimum amplitude in the signal sampled from the first voltage signal are removed.

[0027] The average value of the remaining signal sampled from the first voltage signal is calculated.

[0028] The application provides an electronic voltage transformer and a control method thereof, and the electronic voltage transformer comprises a first voltage dividing branch, a second voltage dividing branch, a direct-current signal conditioning circuit, an alternating-current signal conditioning circuit and a sampling analysis module. The first end of the first voltage dividing branch is electrically connected with the first end of the second voltage dividing branch, the second end of the first voltage dividing branch is electrically connected with the second end of the second voltage dividing branch, the first end of the first voltage dividing branch is connected with an input voltage, the second end of the first voltage dividing branch is grounded, the third end of the first voltage dividing branch is electrically connected with the input end of the direct-current signal conditioning circuit, the output end of the direct-current signal conditioning circuit is electrically connected with the first input end of the sampling analysis module, the third end of the second voltage dividing branch is electrically connected with the input end of the alternating-current signal conditioning circuit, the output end of the alternating-current signal conditioning circuit is electrically connected with the second input end of the sampling analysis module, and the output end of the sampling analysis module is electrically connected with a measuring instrument. In the embodiment, the input voltage is reduced to a small voltage by the first voltage dividing branch and the second voltage dividing branch, and then the small voltage is processed by subsequent modules. The sampling analysis module samples a first voltage signal output by the direct-current signal conditioning circuit to generate an amplitude signal, samples a second voltage signal output by the alternating-current signal conditioning circuit to generate a frequency signal, and identifies the voltage type according to the amplitude signal and the frequency signal, and converts the amplitude signal into a matching signal for output, so as to identify the input voltage type and output the input voltage. In the embodiment, the input voltage of the electronic voltage transformer can be a direct-current voltage or an alternating-current voltage, and the direct-current voltage and the alternating-current voltage can be converted into the matching signal and output to the measuring instrument, thereby improving the applicability of the electronic voltage transformer and simplifying the structure.

[0029] It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the application or to limit the scope of the application. Other features of the application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0031] Figure 1 is a structural schematic diagram of an electronic voltage transformer provided by the embodiment of the application;

[0032] Figure 2 is a structural schematic diagram of another electronic voltage transformer provided by the embodiment of the application;

[0033] Figure 3 is a structural schematic diagram of another electronic voltage transformer provided by the embodiment of the application;

[0034] Figure 4 is a flow chart of a control method of an electronic voltage transformer provided by the embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the personnel in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the person of ordinary skill in the art without making creative efforts should belong to the protection scope of the present application.

[0036] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or system including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or systems.

[0037] Figure 1 is a structural schematic diagram of an electronic voltage transformer provided by the embodiment of the present application, referring to Figure 1 The electronic voltage transformer includes a first voltage dividing branch 10, a second voltage dividing branch 11, a direct current signal conditioning circuit 12, an alternating current signal conditioning circuit 13, and a sampling analysis module 14.

[0038] The first end A1 of the first voltage division branch 10 is electrically connected with the first end B1 of the second voltage division branch 11, the second end A2 of the first voltage division branch 10 is electrically connected with the second end B2 of the second voltage division branch 11, the first end A1 of the first voltage division branch 10 is connected with the input voltage, the second end A1 of the first voltage division branch 10 is connected with the ground GND, the third end A3 of the first voltage division branch 10 is electrically connected with the input end of the direct current signal conditioning circuit 12, the output end of the direct current signal conditioning circuit 12 is electrically connected with the first input end D1 of the sampling analysis module 14, the third end B3 of the second voltage division branch 11 is electrically connected with the input end of the alternating current signal conditioning circuit 13, the output end of the alternating current signal conditioning circuit 13 is electrically connected with the second input end D2 of the sampling analysis module 14, and the output end of the sampling analysis module 14 is electrically connected with the measuring instrument 15; the resistance values of the first voltage division branch 10 and the second voltage division branch 11 are different, so that the voltages output by the third end A3 of the first voltage division branch 10 and the third end B3 of the second voltage division branch 11 are different when the voltages applied to the first voltage division branch 10 and the second voltage division branch 11 are the same;

[0039] The first voltage division branch 10 is configured to transmit the input voltage after being reduced to the direct current signal conditioning circuit 12, and the second voltage division branch 11 is configured to transmit the input voltage after being reduced to the alternating current signal conditioning circuit 13; the direct current signal conditioning circuit 12 is configured to generate a first voltage signal after filtering out the interference signal in the input voltage, and the alternating current signal conditioning circuit 13 is configured to generate a second voltage signal after filtering out the direct current signal and the interference signal in the input voltage; the sampling analysis module 14 is configured to generate an amplitude signal after sampling the first voltage signal and generate a frequency signal after sampling the second voltage signal, and is further configured to identify the voltage type according to the amplitude signal and the frequency signal, and convert the amplitude signal into a matching signal output, the matching signal being a voltage signal or a current signal matched with the measuring instrument 15, and the voltage type including direct current voltage and alternating current voltage.

[0040] The first voltage division branch 10 and the second voltage division branch 11 are connected with the input voltage through the input voltage end INT1, specifically, the first end A1 of the first voltage division branch 10 is electrically connected with the input voltage end INT1, and the input voltage end INT1 is used to provide the input voltage. The input voltage is the voltage on the bus in the power system, and the bus voltage is generally large, while the voltage that the measuring instrument 15 can accept is small, so it is necessary to convert the large voltage on the primary side into small voltage or small current of the same phase and output to the measuring instrument 15. The input voltage end IN1 may be connected with direct current voltage or alternating current voltage, therefore, the electronic voltage transformer needs to identify both alternating current voltage and direct current voltage. Exemplarily, the measuring instrument 15 can be a power meter, an electric meter and an electromechanical protection device.

[0041] The sampling analysis module 14 samples the first voltage signal output from the direct current signal conditioning circuit 12, filters out the chaotic signal through a time domain data filter after sampling the first voltage signal into a digital signal, then removes the maximum amplitude and minimum amplitude in the signal after sampling the first voltage signal, and calculates the average of the remaining sampled signal. In the embodiment, the number of sampling points is exemplarily shown as 512, and the sampling analysis module 14 removes the maximum amplitude and minimum amplitude in the 512 sampled signals, and then calculates the average of the amplitudes of the remaining 510 sampled signals to obtain the amplitude signal.

[0042] The process of generating the frequency signal by the sampling analysis module 14 sampling the second voltage signal output from the alternating current signal conditioning circuit 13 can include: sampling the second voltage signal, performing Fourier transform to generate a frequency domain signal, and obtaining the frequency signal according to the frequency domain signal. Specifically, after sampling the second voltage signal into a digital signal, filtering out the chaotic signal through a time domain data filter, and filtering out the high-order harmonic signal through a low-pass filter, the digital signal is subjected to Fourier transform into a frequency domain signal, and the highest energy frequency in the frequency domain system is obtained as the required frequency signal.

[0043] The amplitude signal and the frequency signal obtained according to the above steps are used for voltage type identification, specifically: if the frequency signal meets a first frequency setting range and the amplitude signal meets a first setting condition, it is determined that the type of the input signal in the electronic voltage transformer is an alternating current signal; if the frequency signal meets a second frequency setting range and the amplitude signal meets a second setting condition, it is determined that the type of the input signal in the electronic voltage transformer is a direct current signal, and each frequency in the first frequency setting range is greater than each frequency in the second frequency setting range. For example, the alternating current signal conditioning circuit 13 includes a direct current blocking capacitor, which is used to filter out the direct current signal in the input voltage. The direct current signal conditioning circuit 12 is used to filter out interference signals. The first frequency setting range, the first setting condition, the second frequency setting range, and the second setting condition are related to the frequency and size of the voltage on the bus, and can be set according to requirements. The alternating current voltage on the bus is generally 25KV, and the direct current voltage is 1500V. In this embodiment, the first frequency setting range is 45HZ-55HZ, and the first setting condition is that the amplitude signal is greater than or equal to 1.7V. The second frequency setting range is 0HZ-5HZ, and the second setting condition is that the amplitude signal is less than 1V. When the input voltage is an alternating current voltage of 25KV, the resistance values of the first voltage dividing branch 10 and the second voltage dividing branch 11 are set such that the voltage output by the third end A3 of the first voltage dividing branch 10 is 25V, and the voltage output by the third end B3 of the second voltage dividing branch 11 is 2.5V. The voltage output by the first voltage dividing branch 10 is input into the direct current signal conditioning circuit 12, and then sampled by the sampling and analysis module 14 to generate an amplitude signal, which is about 2.5V. The voltage output by the second voltage dividing branch 11 is input into the alternating current signal conditioning circuit 13, and then sampled by the sampling and analysis module 14 to generate a frequency signal, and the frequency corresponding to the alternating current signal is generally located in the range of 45-55HZ. Therefore, when the sampling and analysis module determines that the frequency signal is located in the range of 45HZ-55HZ and the amplitude signal is greater than or equal to 1.7V, it is determined that the type of the input voltage is an alternating current voltage. When the input voltage is a direct current voltage, the voltage output by the alternating current signal conditioning circuit 13 is 0, that is, no direct current voltage signal is output, and some noise signals may be output. Therefore, the frequency signal generated by the sampling and analysis module 14 after sampling the second voltage signal is about 0. Therefore, if the sampling and analysis module 14 determines that the frequency signal is located in the range of 0-5HZ and the amplitude signal is less than 1V, it is determined that the type of the input voltage is a direct current voltage.

[0044] The measurement instrument 15 can only be able to identify a voltage signal or only be able to identify a current signal. When the measurement instrument 15 is only able to identify a voltage signal, the sampling and analysis module 14 converts the amplitude signal into a voltage input that can be accepted by the measurement instrument and inputs it into the instrument. When the measurement instrument 15 is only able to identify a current signal, the sampling and analysis module 14 converts the amplitude signal into a current signal that can be accepted by the measurement instrument and inputs it into the instrument.

[0045] The electronic voltage transformer in the embodiment of the present application can automatically identify the type of the input voltage and output, that is, can output the DC voltage to the measuring instrument and output the AC voltage to the measuring instrument, and is more suitable. And selecting two voltage dividing branches can realize that the AC voltage and the DC voltage are in the same order after voltage division, so that the circuit is simpler when subsequent signal conversion is performed, and the circuit structure of the electronic voltage transformer is simplified.

[0046] Figure 2 Another structure schematic diagram of the electronic voltage transformer provided by the embodiment of the present application is provided with reference to Figure 2 Optionally, the first voltage dividing branch 10 includes a first resistor R1 and a second resistor R2, a first end of the first resistor R1 is taken as a first end A1 of the first voltage dividing branch 10, a second end of the first resistor R1 is electrically connected with a first end of the second resistor R2, the second end of the first resistor R1 is taken as a third end A3 of the first voltage dividing branch 10, and a second end of the second resistor R2 is taken as a second end A2 of the first voltage dividing branch 10.

[0047] The second voltage dividing branch 11 includes a third resistor R3 and a fourth resistor R4, a first end of the third resistor R3 is taken as a first end B1 of the second voltage dividing branch 11, a second end of the third resistor R3 is electrically connected with a first end of the fourth resistor R4, the second end of the third resistor R3 is taken as a third end B3 of the second voltage dividing branch 11, and a second end of the fourth resistor R4 is taken as a second end B2 of the second voltage dividing branch 11.

[0048] The first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 realize voltage conversion of the input voltage, that is, conversion into a small voltage, the structure is simple, the volume is small, and the miniaturization of the device is facilitated. Optionally, the ratio of the resistance values of the first resistor R1 and the second resistor R2 is a first ratio, the ratio of the resistance values of the third resistor R3 and the fourth resistor R4 is a second ratio, and the ratio of the second ratio to the first ratio ranges from 5 to 25.

[0049] The input voltage, if it is an AC voltage, is generally 25KV, and if it is a DC voltage, is generally 1500V, i.e. the AC voltage value and the DC voltage value differ by about 16 times. For example, if the input voltage is a DC voltage, the 1500V DC voltage is input into the first voltage dividing branch 10 and the second voltage dividing branch 11, and the voltage output from the third end A3 of the first voltage dividing branch 10 is 1.5V, and the first ratio is 999. If the input voltage is an AC voltage, the 25KV AC voltage is input into the first voltage dividing branch 10 and the second voltage dividing branch 11, and the voltage output from the third end B3 of the second voltage dividing branch 11 is about 1.5V, in order to be in the same order of magnitude as the voltage output from the third end A3 of the first voltage dividing branch 10 when the input voltage is a DC voltage. If the voltage output from the third end B3 of the second voltage dividing branch 11 is 1V, the second ratio is 24999, and if the voltage output from the third end B3 of the second voltage dividing branch 11 is 5V, the second ratio is 4999, i.e. the ratio of the second ratio to the first ratio is about 5-25.

[0050] With continued reference to Figure 2 Optionally, the DC signal conditioning circuit 12 comprises a voltage stabilizer 121, a current limiting protection unit 122, a first filter resistor R5 and a first filter capacitor C1. The first end of the voltage stabilizer 121 is electrically connected to the third end A3 of the first voltage dividing branch 10, and the first end of the voltage stabilizer 121 is also electrically connected to the input end of the current limiting protection unit 122. The output end of the current limiting protection unit 122 is electrically connected to the first end of the first filter resistor R5. The second end of the first filter resistor R5 is electrically connected to the first end of the first filter capacitor C1. The second end of the first filter capacitor C1 is grounded GND. The second end of the first filter resistor R5 is electrically connected to the first input end D1 of the sampling and analysis module 14.

[0051] The direct current signal conditioning circuit 12 further comprises a first modulation unit 123 connected between the output of the current limiting protection unit 122 and the first end of the first filter resistor R5, the first modulation unit 123 comprising an inductor and a capacitor for modulating the amplitude of the voltage. The voltage stabilizer 121 can be a Schottky diode, which stabilizes the voltage output by the third end A3 of the first voltage dividing branch 10 within a certain range. For example, when the voltage output by the third end A3 of the first voltage dividing branch 10 is 5V, the voltage stabilizer 121 pulls down the 5V voltage to 3V and then outputs it to the current limiting protection unit 122, avoiding excessive voltage and damaging the device. The current limiting protection unit 122 can be a MAX14626 chip, which limits the voltage input to the input end within a set threshold. For example, when the voltage input to the current limiting protection unit 122 is less than or equal to the set threshold, the voltage output by the current limiting protection unit 122 is equal to the voltage input to the input end; when the voltage input to the current limiting protection unit 122 is greater than the set threshold, the voltage output by the current limiting protection unit 122 is the set threshold. By controlling the size of the voltage output by the current limiting protection unit 122, the current limiting effect is achieved, avoiding excessive current in the circuit. The first filter resistor R5 and the first filter capacitor C1 form a first-order filter to filter interference signals in the circuit. When the input voltage is a direct current voltage, the direct current voltage is filtered of interference signals after passing through the direct current signal conditioning circuit 12, making the waveform of the direct current voltage smoother. When the input voltage is an alternating current voltage, the amplitude of the alternating current voltage is modulated after passing through the first modulation unit 123 in the direct current signal conditioning circuit 12, and the amplitude is approximately modulated to the effective value.

[0052] With reference to Figure 2 Optionally, the alternating current signal conditioning circuit 13 comprises a first direct current blocking capacitor C2, a second direct current blocking capacitor C3, a voltage follower 131, an analog-to-digital conversion unit 132, a second filter resistor R6, and a second filter capacitor C4.

[0053] The first end of the first direct current blocking capacitor C2 is electrically connected to the third end B3 of the second voltage dividing branch 11, the second end of the first direct current blocking capacitor C2 is electrically connected to the first end of the second direct current blocking capacitor C3, the second end of the second direct current blocking capacitor C3 is electrically connected to the first end of the second filter resistor R6, the second end of the second filter resistor R6 is electrically connected to the first end of the second filter capacitor C4, the second end of the second filter resistor R6 is also electrically connected to the input end of the voltage follower 131, the output end of the voltage follower 131 is electrically connected to the input end of the analog-to-digital conversion unit 132, and the output end of the analog-to-digital conversion unit 132 is electrically connected to the second input end D2 of the sampling analysis module 14.

[0054] The AC signal conditioning circuit 13 further comprises a second modulation circuit 133 connected between the first end of the first DC blocking capacitor C2 and the third end B3 of the second voltage dividing branch 11. The second modulation circuit 133 comprises an inductor and a capacitor for modulating the voltage value in the circuit. The first DC blocking capacitor C2 and the second DC blocking capacitor C3 are used to filter out the DC signal in the input AC signal conditioning circuit 13. The second filter resistor R6 and the second filter capacitor C4 form a first-order filter to filter out the interference signal in the circuit. The output voltage of the voltage follower 131 is equal to the input voltage, and the voltage follower 131 is used to isolate the circuits before and after the voltage follower 131, so as not to affect each other. The analog-to-digital conversion unit 132 can be an AD7190 chip, which is used to convert the analog signal into a digital signal input into the sampling analysis module 14. Specifically, the CS end, the SCLK end, the DIN end and the DOUT end of the analog-to-digital conversion unit 132 are connected with the sampling analysis module 14, that is, the second input end D2 of the sampling analysis module 14 comprises four ports, which are electrically connected with the four ports of the analog-to-digital conversion unit 132 one by one. When the input voltage is a DC voltage, the DC voltage is filtered out after passing through the AC signal conditioning circuit 13, and the interference signal in the output circuit of the AC signal conditioning circuit 13 is not filtered out. When the input voltage is an AC voltage, the AC voltage is filtered after passing through the AC signal conditioning circuit 13, so that the waveform of the AC voltage is smoother.

[0055] Figure 3 Another structure schematic diagram of an electronic voltage transformer is provided for the embodiment of the application, referring to Figure 3 Optionally, the sampling analysis module 14 comprises a first sampling circuit 141, a second sampling circuit 142, a controller 143 and an output module 144. The input end of the first sampling circuit 141 is electrically connected with the output end of the DC signal conditioning circuit 12, the output end of the first sampling circuit 141 is electrically connected with the first end of the controller 143, the input end of the second sampling circuit 142 is electrically connected with the output end of the AC signal conditioning circuit 13, the output end of the second sampling circuit 142 is electrically connected with the second end of the controller 143, the output end of the controller 143 is electrically connected with the input end of the output module 144, and the output end of the output module 144 is electrically connected with the measuring instrument 15. The controller 143 is configured to generate an amplitude signal according to the first voltage signal, generate a frequency signal according to the second voltage signal, and perform voltage type identification according to the amplitude signal and the frequency signal. The output module is configured to convert the amplitude signal into a matching signal.

[0056] The input end of the first sampling circuit 141 is the first input end D1 of the sampling and dividing module 14, and the input end of the second sampling circuit 142 is the second input end D2 of the sampling and analyzing module 14. The first sampling circuit 141 is configured to sample the first voltage signal output by the output end of the direct-current signal conditioning circuit 12 and input the first voltage signal to the controller 143, and the second sampling circuit 142 is configured to sample the second voltage signal output by the output end of the alternating-current signal conditioning circuit 13 and input the second voltage signal to the controller 143. The controller 143 generates an amplitude signal according to the sampled first voltage signal, generates a frequency signal according to the sampled second voltage signal, and performs voltage type identification according to the amplitude signal and the frequency signal. The output module 144 is configured to convert the amplitude signal into a matching signal matched with the measuring instrument 15. The matching signal is a voltage signal or a current signal that can be accepted by the measuring instrument 15. When the matching signal is a voltage signal, the output module 144 only adjusts the size of the amplitude signal, and converts the amplitude signal into a voltage signal within the amplitude range that can be accepted by the measuring instrument 15. When the matching signal is a current signal, the output module 144 converts the voltage signal into a current signal and adjusts the amplitude, so that the current signal is within the amplitude range that can be accepted by the measuring instrument 15. It is worth noting that the controller 143 can be integrated with a digital-to-analog conversion circuit, which converts the amplitude signal into an analog signal and outputs the analog signal to the output module 144.

[0057] With reference to the foregoing Figure 3 Optionally, the electronic voltage transformer further comprises a first indicating module 16 and a second indicating module 17. The first indicating module 16 is electrically connected to the sampling and analyzing module 14, and the second indicating module 17 is electrically connected to the sampling and analyzing module 14. The sampling and analyzing module 14 is configured to control the second indicating module 17 to be turned on when the voltage type identification result is determined to be alternating voltage, and control the first indicating module 16 to be turned on when the voltage type identification result is determined to be direct-current voltage.

[0058] For example, when the sampling and analyzing module 14 comprises a controller, the first indicating module 16 and the second indicating module 17 are electrically connected to the controller. The first indicating module 16 and the second indicating module 17 can be indicator lights, and the colors emitted by the two indicator lights are different. When the sampling and analyzing module 14 determines that the input voltage is direct-current voltage, a potential signal can be output to control the first indicating module 16 to be turned on. When the sampling and analyzing module 14 determines that the input voltage is alternating voltage, a potential signal can be output to control the second indicating module 17 to be turned on. By setting the first indicating module 16 and the second indicating module 17, the user can intuitively determine the type of input voltage.

[0059] The embodiment of the present application also provides a control method of an electronic voltage transformer, which is used for controlling the electronic voltage transformer in any of the above embodiments, and the electronic voltage transformer comprises a first voltage dividing branch, a second voltage dividing branch, a direct-current signal conditioning circuit, an alternating-current signal conditioning circuit, a sampling and analyzing module, Figure 4 The embodiment of the present application provides a flow chart of the control method of the electronic voltage transformer, as shown in Figure 4 The control method comprises the following steps.

[0060] S101: The first voltage dividing branch transmits the input voltage after being reduced to the direct-current signal conditioning circuit, and the second voltage dividing branch transmits the input voltage after being reduced to the alternating-current signal conditioning circuit.

[0061] S102: The direct-current signal conditioning circuit generates a first voltage signal after filtering out the interference signal in the input voltage, and the alternating-current signal conditioning circuit generates a second voltage signal after filtering out the direct-current signal and the interference signal in the input voltage.

[0062] S103: The sampling and analyzing module generates an amplitude signal after sampling the first voltage signal, generates a frequency signal after sampling the second voltage signal, identifies the voltage type according to the amplitude signal and the frequency signal, and converts the amplitude signal into a matching signal, wherein the matching signal is a voltage signal or a current signal matched with a measuring instrument, and the voltage type comprises a direct-current voltage and an alternating-current voltage.

[0063] Optionally, the sampling and analyzing module identifies the voltage type according to the amplitude signal and the frequency signal, and the identification comprises the following steps.

[0064] If the frequency signal meets a first frequency setting range and the amplitude signal meets a first setting condition, it is determined that the type of the input signal in the electronic voltage transformer is an alternating-current signal.

[0065] If the frequency signal meets a second frequency setting range and the amplitude signal meets a second setting condition, it is determined that the type of the input signal in the electronic voltage transformer is a direct-current signal, and each frequency in the first frequency setting range is greater than each frequency in the second frequency setting range.

[0066] Optionally, the sampling and analyzing module generates the amplitude signal after sampling the first voltage signal, and generates the frequency signal after sampling the second voltage signal, and the generation comprises the following steps.

[0067] The second voltage signal is sampled and then Fourier transformed to generate a frequency domain signal, and the frequency signal is obtained according to the frequency domain signal.

[0068] The first voltage signal is sampled and then calculated according to a setting method to generate the amplitude signal.

[0069] Optionally, the first voltage signal is calculated according to the setting method to generate the amplitude signal, and the calculation comprises the following steps.

[0070] remove the maximum amplitude and the minimum amplitude from the sampled first voltage signal;

[0071] calculate the average of the remaining sampled signal.

[0072] The control method of the electronic voltage transformer has the same beneficial effects as the electronic voltage transformer, and the embodiments will not be described here.

[0073] It should be understood that various forms of flow shown above can be used to reorder, add or delete steps. For example, each step described in the present application can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, and the present application is not limited herein.

[0074] The above specific embodiments do not constitute a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. An electronic voltage transformer, characterized by The application relates to a voltage signal type identification device and method. The first end of the first voltage dividing branch is electrically connected with the first end of the second voltage dividing branch, the second end of the first voltage dividing branch is electrically connected with the second end of the second voltage dividing branch, the first end of the first voltage dividing branch is connected with a to-be-input voltage, the second end of the first voltage dividing branch is grounded, the third end of the first voltage dividing branch is electrically connected with the input end of the direct-current signal conditioning circuit, the output end of the direct-current signal conditioning circuit is electrically connected with the first input end of the sampling analysis module, the third end of the second voltage dividing branch is electrically connected with the input end of the alternating-current signal conditioning circuit, the output end of the alternating-current signal conditioning circuit is electrically connected with the second input end of the sampling analysis module, and the output end of the sampling analysis module is electrically connected with a measuring instrument; the resistance values of the first voltage dividing branch and the second voltage dividing branch are different, so that the voltages output by the third end of the first voltage dividing branch and the third end of the second voltage dividing branch are different when the voltages applied to the first voltage dividing branch and the second voltage dividing branch are the same. The first voltage dividing branch is configured to transmit the to-be-input voltage after voltage reduction to the direct-current signal conditioning circuit, the second voltage dividing branch is configured to transmit the to-be-input voltage after voltage reduction to the alternating-current signal conditioning circuit, the direct-current signal conditioning circuit is configured to generate a first voltage signal after filtering out interference signals in the to-be-input voltage, the alternating-current signal conditioning circuit is configured to generate a second voltage signal after filtering out direct-current signals and interference signals in the to-be-input voltage, and the sampling analysis module is configured to generate an amplitude signal after sampling the first voltage signal, generate a frequency signal after sampling the second voltage signal, and further configured to identify a voltage type according to the amplitude signal and the frequency signal, and convert the amplitude signal into a matching signal output, wherein the matching signal is a voltage signal or a current signal matched with the measuring instrument, and the voltage type includes a direct-current voltage and an alternating-current voltage. The first voltage dividing branch comprises a first resistor and a second resistor, the first end of the first resistor is the first end of the first voltage dividing branch, the second end of the first resistor is electrically connected with the first end of the second resistor, and the second end of the first resistor is the third end of the first voltage dividing branch; and the second end of the second resistor is the second end of the first voltage dividing branch.

2. The electronic voltage transformer according to claim 1, characterized in that The second voltage dividing branch comprises a third resistor and a fourth resistor, the first end of the third resistor is the first end of the second voltage dividing branch, the second end of the third resistor is electrically connected with the first end of the fourth resistor, the second end of the third resistor is the third end of the second voltage dividing branch, and the second end of the fourth resistor is the second end of the second voltage dividing branch. ​ 3. The electronic voltage transformer according to claim 1, characterized in that, The direct current signal conditioning circuit comprises a voltage stabilizer, a current limiting protection unit, a first filter resistor and a first filter capacitor, the first end of the voltage stabilizer is electrically connected with the third end of the first voltage dividing branch, the first end of the voltage stabilizer is also electrically connected with the input end of the current limiting protection unit, the output end of the current limiting protection unit is electrically connected with the first end of the first filter resistor, the second end of the first filter resistor is electrically connected with the first end of the first filter capacitor, the second end of the first filter capacitor is grounded, and the second end of the first filter resistor is electrically connected with the first input end of the sampling analysis module. The direct current signal conditioning circuit further comprises a first modulation unit, which is connected between the output end of the current limiting protection unit and the first end of the first filter resistor, and the first modulation unit comprises a first inductor, a second inductor and a first capacitor, the first end of the first inductor is connected with the output end of the current limiting protection unit, the second end of the first inductor is connected with the first end of the second inductor, the second end of the second inductor is connected with the first end of the first filter resistor, the first end of the first capacitor is connected with the second end of the first inductor, the second end of the first capacitor is grounded, and the first modulation unit is used for modulating the amplitude of the voltage.

4. The electronic voltage transformer of claim 1, wherein, The alternating current signal conditioning circuit comprises a first direct-current capacitor, a second direct-current capacitor, a voltage follower, an analog-to-digital conversion unit, a second filter resistor and a second filter capacitor. The first end of the first direct-current capacitor is electrically connected with the third end of the second voltage dividing branch, the second end of the first direct-current capacitor is electrically connected with the first end of the second direct-current capacitor, the second end of the second direct-current capacitor is electrically connected with the first end of the second filter resistor, the second end of the second filter resistor is electrically connected with the first end of the second filter capacitor, the second end of the second filter resistor is also electrically connected with the input end of the voltage follower, the output end of the voltage follower is electrically connected with the input end of the analog-to-digital conversion unit, and the output end of the analog-to-digital conversion unit is electrically connected with the second input end of the sampling analysis module. The second end of the second filter capacitor is grounded. The alternating current signal conditioning circuit further comprises a second modulation circuit, which is connected between the first end of the first direct-current capacitor and the third end of the second voltage dividing branch, and the second modulation circuit comprises a third inductor, a fourth inductor and a second capacitor, the first end of the third inductor is connected with the third end of the second voltage dividing branch, the second end of the third inductor is connected with the first end of the fourth inductor, the second end of the fourth inductor is connected with the first end of the first direct-current capacitor, the first end of the second capacitor is connected with the second end of the third inductor, the second end of the second capacitor is grounded, and the second modulation circuit is used for modulating the voltage value in the circuit.

5. The electronic voltage transformer of claim 1, wherein, The sampling analysis module comprises a first sampling circuit, a second sampling circuit, a controller and an output module; an input end of the first sampling circuit is electrically connected with an output end of the direct-current signal conditioning circuit, an output end of the first sampling circuit is electrically connected with a first end of the controller, an input end of the second sampling circuit is electrically connected with an output end of the alternating-current signal conditioning circuit, an output end of the second sampling circuit is electrically connected with a second end of the controller, an output end of the controller is electrically connected with an input end of the output module, and an output end of the output module is electrically connected with the measuring instrument; the controller is configured to generate the amplitude signal according to the first voltage signal, generate the frequency signal according to the second voltage signal, and perform voltage type identification according to the amplitude signal and the frequency signal; and the output module is configured to convert the amplitude signal into a matching signal.

6. The electronic voltage transformer of claim 1, wherein, Further comprising a first indicating module and a second indicating module, the first indicating module is electrically connected with the sampling analysis module, the second indicating module is electrically connected with the sampling analysis module, the sampling analysis module is configured to determine that the voltage type identification result is alternating voltage, control the second indicating module to be turned on, and determine that the voltage type identification result is direct-current voltage, control the first indicating module to be turned on.

7. A control method of an electronic voltage transformer, characterized by, The control method of the electronic voltage transformer of any one of claims 1-6, the electronic voltage transformer comprising a first voltage dividing branch, a second voltage dividing branch, a direct-current signal conditioning circuit, an alternating-current signal conditioning circuit, a sampling analysis module, the control method of the electronic voltage transformer comprising: The first voltage dividing branch transmits the input voltage after being reduced to the direct-current signal conditioning circuit, and the second voltage dividing branch transmits the input voltage after being reduced to the alternating-current signal conditioning circuit; The direct-current signal conditioning circuit generates a first voltage signal after filtering out the interference signal in the input voltage, and the alternating-current signal conditioning circuit generates a second voltage signal after filtering out the direct-current signal and the interference signal in the input voltage; The sampling analysis module generates an amplitude signal after sampling the first voltage signal, generates a frequency signal after sampling the second voltage signal, performs voltage type identification according to the amplitude signal and the frequency signal, and converts the amplitude signal into a matching signal, the matching signal being a voltage signal or a current signal matched with the measuring instrument, and the voltage type comprising direct-current voltage and alternating-current voltage.

8. The control method of the electronic voltage transformer according to claim 7, characterized by, The voltage type identification performed by the sampling analysis module according to the amplitude signal and the frequency signal comprises: If the frequency signal meets a first frequency setting range and the amplitude signal meets a first setting condition, it is determined that the type of the input signal in the electronic voltage transformer is an alternating-current signal; If the frequency signal meets a second frequency setting range and the amplitude signal meets a second setting condition, it is determined that the type of the input signal in the electronic voltage transformer is a direct-current signal, and each frequency in the first frequency setting range is greater than each frequency in the second frequency setting range.

9. The control method of the electronic voltage transformer according to claim 7, characterized by, The sampling analysis module generates an amplitude signal after sampling the first voltage signal and generates a frequency signal after sampling the second voltage signal, comprising: performing Fourier transform on the second voltage signal after sampling to generate a frequency domain signal, and obtaining the frequency signal according to the frequency domain signal; generating an amplitude signal after sampling the first voltage signal and calculating according to a set method.

10. The control method of the electronic voltage transformer according to claim 9, characterized by, The method for generating an amplitude signal after calculating the first voltage signal according to a set method comprises: removing the maximum amplitude and the minimum amplitude in the signal after sampling the first voltage signal; calculating the average value of the remaining signal after sampling.

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