Electrician instrument field calibration device and calibration result optimization method

Abstract

The invention discloses an electrical instrument field calibration device and a calibration result optimization method, and the device comprises a power supply unit which is used for providing a working power supply for the device; the central control unit is used for controlling the work of the device; the direct-current voltage output module is used for outputting direct-current voltage within a set range; the direct current output module is used for outputting direct current in a set range; the alternating-current voltage output module is used for outputting alternating-current voltage within a set range; the alternating current output module is used for outputting alternating current in a set range; the direct current sampling module is used for measuring the direct current output by the detected equipment; the man-machine interaction module comprises input equipment and display equipment and is used for user interaction; wherein the modules are connected in series through the central control unit and are controlled and coordinated by the central control unit to work, and the modules and the central control unit are coupled with the power supply unit.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical instrument calibration, and more specifically, relates to an on-site calibration device for an electrical instrument and a calibration result optimization method. Background Art

[0002] Electrical instrument calibration is an important step to ensure measurement accuracy, involving a variety of electrical instrument calibration methods and precautions. The following are the calibration methods and importance of ammeters, voltmeters, power meters, ohmmeters, and multimeters:

[0003] 1. Calibration method:

[0004] Ammeter: Using the comparison method, use a standard ammeter of known accuracy as a reference. Connect the ammeter to be calibrated in series with the standard ammeter in the circuit. Adjust the reading to make it the same as the standard ammeter reading. Record the calibration data at multiple current values and analyze them.

[0005] Voltmeter: Also using the comparison method, use a standard voltage source of known accuracy as a reference. Connect the voltmeter to be calibrated in parallel with the standard voltage source and connect it to the circuit. Adjust the reading to make it the same as the voltage value of the standard voltage source. Record the calibration data at multiple different voltage values and analyze them.

[0006] Power meter: Both current and voltage measurements must be considered simultaneously. Using a standard power source as a reference, connect the power meter to be calibrated to the circuit of the standard power source. Adjust the reading to match the power value of the standard power source. Record and analyze the calibration data at multiple power values.

[0007] Ohmmeter: Using the substitution method, use a standard resistor of known value as a reference. Connect the ohmmeter to be calibrated to the circuit containing the standard resistor. Adjust the reading to match the value of the standard resistor. Record and analyze the calibration data at multiple resistance values.

[0008] Multimeter: When measuring multiple parameters such as current, voltage, and resistance, calibrate each parameter separately, paying attention to the cross-influence between different parameters.

[0009] 2. Importance of calibration:

[0010] Calibration is the basis for ensuring the measurement accuracy of instruments. Calibration can eliminate instrument errors, improve measurement accuracy, and ensure the stability and reliability of electronic systems1.

[0011] Calibration helps to identify potential problems with the instrument and promptly repair or replace it, thus avoiding losses during production or experiments.

[0012] However, the calibration method in the prior art has low accuracy, and therefore a calibration device is urgently needed to solve the technical problem of low accuracy. Summary of the Invention

[0013] To solve the above technical problems, the present invention proposes an on-site calibration device for electrical instruments, comprising:

[0014] A power supply unit, used to provide working power for the device;

[0015] A central control unit, used to control the operation of the device;

[0016] DC voltage output module, used to output DC voltage within the set range;

[0017] DC current output module, used to output DC current within a set range;

[0018] AC voltage output module, used to output AC voltage within the set range;

[0019] AC current output module, used to output AC current within a set range;

[0020] DC current sampling module, used to measure the DC current output by the device under test;

[0021] Human-computer interaction module, including input devices and display devices, for user interaction;

[0022] The modules are connected in series through the central control unit and are controlled and coordinated by the central control unit, and the modules and the central control unit are coupled to the power supply unit.

[0023] Furthermore, the DC voltage output module includes:

[0024] A reference voltage source, used for providing a reference DC voltage;

[0025] A programmable gain amplifier is used to amplify the reference DC voltage according to the set range;

[0026] The feedback system is used to detect the DC voltage output and feed it back to the programmable gain amplifier to form a closed-loop control.

[0027] Furthermore, the DC current output module includes:

[0028] A reference voltage source, used for providing a reference DC voltage;

[0029] A programmable gain amplifier is used to amplify the reference DC voltage according to the set range;

[0030] A transconductance amplifier, used to convert the amplified reference DC voltage into a corresponding DC current output;

[0031] The feedback system is used to detect the DC current output and feed it back to the programmable gain amplifier to form a closed-loop control.

[0032] Furthermore, the AC voltage output module includes:

[0033] Digital synthesizer, used to synthesize sinusoidal digital signals according to the set frequency, amplitude and phase;

[0034] A digital-to-analog converter, configured to convert the sinusoidal digital signal into an analog sinusoidal signal;

[0035] A programmable gain amplifier, configured to amplify the amplitude of the analog sine wave signal;

[0036] The feedback system is used to detect the AC voltage output and feed it back to the programmable gain amplifier to form a closed-loop control.

[0037] Furthermore, the AC current output module includes:

[0038] Digital synthesizer, used to synthesize sinusoidal digital signals according to the set frequency, amplitude and phase;

[0039] A digital-to-analog converter, configured to convert the sinusoidal digital signal into an analog sinusoidal signal;

[0040] A programmable gain amplifier, configured to amplify the amplitude of the sine wave signal;

[0041] a transconductance amplifier, configured to convert the amplified sinusoidal wave signal into a corresponding alternating current output;

[0042] The feedback system is used to detect the AC current output and feed it back to the programmable gain amplifier to form a closed-loop control.

[0043] Furthermore, the human-computer interaction module includes a keyboard, a display screen and a communication interface.

[0044] The present invention also proposes a calibration result optimization method for an on-site calibration device for an electrical instrument, comprising:

[0045] Acquire voltage information and current information of an electrical instrument field calibration device, wherein the voltage information includes: voltage output and reference voltage, and the current information includes: current output and reference current;

[0046] respectively setting a voltage output error calculation model and a current output error calculation model, and calculating the voltage output error and the current output error based on the voltage information and the current information;

[0047] respectively setting a feedback voltage calculation model and a feedback current calculation model, and calculating the feedback voltage and the feedback current according to the error of the voltage output and the error of the current output;

[0048] The voltage optimization objective function and the current optimization objective function are set separately, and the feedback voltage and the feedback current are combined to complete the voltage output and current output optimization by minimizing the voltage optimization objective function and the current optimization objective function.

[0049] Furthermore, the voltage output error calculation model includes:

[0050]

[0051] The error calculation model of the current output includes:

[0052]

[0053] Among them, ∈ V (t) is the error of voltage output at time t, and the voltage output includes DC voltage output and AC voltage output, γ V (t) is the first adjustment factor of the error calculation model of the voltage output at time t, U measured is the voltage output, U std is a reference voltage, and the reference voltage includes: a reference DC voltage and a reference AC voltage, V (t) is the second adjustment factor of the error calculation model of the voltage output at time t, ∈ I (t) is the error of current output at time t, γ I (t) is the first adjustment factor of the error calculation model of the current output at time t, I measured is the current output, I std is the reference current, ζ I (t) is the second adjustment factor of the error calculation model of the current output at time t.

[0054] Furthermore, the feedback voltage calculation model includes:

[0055]

[0056] The feedback current calculation model includes:

[0057]

[0058] Among them, U adjusted (t) is the feedback voltage at time t, δ V (t) is the first adjustment factor of the feedback voltage calculation model at time t, η V(t) is the second adjustment factor of the feedback voltage calculation model at time t, λ V is the third adjustment factor of the feedback voltage calculation model, I adjusted (t) is the feedback current at time t, δ I (t) is the first adjustment factor of the feedback current calculation model at time t, η I (t) is the second adjustment factor of the feedback current calculation model at time t, λ I It is the third adjustment factor of the feedback current calculation model.

[0059] Furthermore, the voltage optimization objective function J used to calibrate and optimize the voltage is V include:

[0060]

[0061] Current optimization objective function J for current calibration optimization I include:

[0062]

[0063] Where T′ is the time period, λ V is the first adjustment factor of the voltage optimization objective function, μ V is the second adjustment factor of the voltage optimization objective function, α V is the third adjustment factor of the voltage optimization objective function, β V is the fourth adjustment factor of the voltage optimization objective function, T(t) is the ambient temperature at time t, T0 is the reference temperature, γ V is the fifth adjustment factor of the voltage optimization objective function, H(t) is the ambient humidity at time t, H0 is the reference humidity, δ V is the sixth adjustment factor of the voltage optimization objective function, n is the seventh adjustment factor of the voltage optimization objective function, λ I is the first adjustment factor of the current optimization objective function, μ I The second adjustment factor of the current optimization objective function, α I is the third adjustment factor of the current optimization objective function, β I is the fourth adjustment factor of the current optimization objective function, γ I is the fifth adjustment factor of the current optimization objective function, δ I is the sixth adjustment factor of the current optimization objective function, and m is the seventh adjustment factor of the current optimization objective function.

[0064] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0065] The present invention can complete on-site calibration of electrical instruments through the above technical solutions, and can optimize the calibration results through the calibration result optimization method, so that the final calibration results of the electrical instruments are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 This is a rendering of the device according to Example 1 of the present invention;

[0067] Figure 2 This is a block diagram of the overall design of the device according to embodiment 1 of the present invention;

[0068] Figure 3 This is a block diagram of a closed-loop feedback design of the device according to embodiment 1 of the present invention;

[0069] Figure 4 This is a flow chart of the method of embodiment 2 of the present invention. DETAILED DESCRIPTION

[0070] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0071] The method provided by the present invention can be implemented in the following terminal environment, wherein the terminal may include one or more of the following components: a processor, a storage medium, and a display screen. The storage medium stores at least one instruction, which is loaded and executed by the processor to implement the method described in the following embodiments.

[0072] A processor can include one or more processing cores. It connects various components within the terminal using various interfaces and circuits. It executes instructions, programs, code sets, or instruction sets stored in storage media, and accesses data stored in storage media to perform various terminal functions and process data.

[0073] The storage medium may include a random access memory (RAM) or a read-only memory (ROM). The storage medium may be used to store instructions, programs, codes, code sets, or instructions.

[0074] The display is used to show the user interface of each application.

[0075] In addition, those skilled in the art will appreciate that the structure of the terminal described above does not limit the terminal. The terminal may include more or fewer components, or a combination of certain components, or a different arrangement of components. For example, the terminal may also include a radio frequency circuit, an input unit, a sensor, an audio circuit, a power supply, and other components, which will not be described in detail here.

[0076] Example 1

[0077] An embodiment of the present invention provides an on-site calibration device for an electrical instrument, comprising:

[0078] A power supply unit, used to provide working power for the device;

[0079] A central control unit, used to control the operation of the device;

[0080] DC voltage output module, used to output DC voltage within the set range;

[0081] DC current output module, used to output DC current within a set range;

[0082] AC voltage output module, used to output AC voltage within the set range;

[0083] AC current output module, used to output AC current within a set range;

[0084] DC current sampling module, used to measure the DC current output by the device under test;

[0085] Human-computer interaction module, including input devices and display devices, for user interaction;

[0086] The modules are connected in series through the central control unit and are controlled and coordinated by the central control unit, and the modules and the central control unit are coupled to the power supply unit.

[0087] Specifically, the DC voltage output module includes:

[0088] A reference voltage source, used for providing a reference DC voltage;

[0089] A programmable gain amplifier is used to amplify the reference DC voltage according to the set range;

[0090] The feedback system is used to detect the DC voltage output and feed it back to the programmable gain amplifier to form a closed-loop control.

[0091] Specifically, the DC current output module includes:

[0092] A reference voltage source, used for providing a reference DC voltage;

[0093] A programmable gain amplifier is used to amplify the reference DC voltage according to the set range;

[0094] A transconductance amplifier, used to convert the amplified reference DC voltage into a corresponding DC current output;

[0095] The feedback system is used to detect the DC current output and feed it back to the programmable gain amplifier to form a closed-loop control.

[0096] Specifically, the AC voltage output module includes:

[0097] Digital synthesizer, used to synthesize sinusoidal digital signals according to the set frequency, amplitude and phase;

[0098] A digital-to-analog converter, configured to convert the sinusoidal digital signal into an analog sinusoidal signal;

[0099] A programmable gain amplifier, configured to amplify the amplitude of the analog sine wave signal;

[0100] The feedback system is used to detect the AC voltage output and feed it back to the programmable gain amplifier to form a closed-loop control.

[0101] Specifically, the AC current output module includes:

[0102] Digital synthesizer, used to synthesize sinusoidal digital signals according to the set frequency, amplitude and phase;

[0103] A digital-to-analog converter, configured to convert the sinusoidal digital signal into an analog sinusoidal signal;

[0104] A programmable gain amplifier, configured to amplify the amplitude of the sine wave signal;

[0105] a transconductance amplifier, configured to convert the amplified sinusoidal wave signal into a corresponding alternating current output;

[0106] The feedback system is used to detect the AC current output and feed it back to the programmable gain amplifier to form a closed-loop control.

[0107] Specifically, the human-computer interaction module includes a keyboard, a display screen and a communication interface.

[0108] The following is a specific example of this embodiment, as shown below:

[0109] The instruments calibrated by this device are shown in Table 1, primarily including AC / DC voltage and AC / DC current functions. It also features an RS232 interface, enabling programmable control, automatic report generation, electronic output of on-site calibration data and certificates, and analysis of calibration intervals for the instruments being tested.

[0110] Table 1 Calibrated instruments and their performance

[0111] Serial number name scope Accuracy 1 Analog pointer meter model 7421 DC voltage: (0~60)mV Level 1.5 2 Analog pointer meter model 4532 DC voltage: (0~75)mV Level 1.5 3 Analog pointer meter model 9678 DC voltage: (0~30)V Level 1.5 4 Analog pointer meter model 4531 AC voltage: (0~350)V Level 1.5 5 Analog pointer meter model 7682 DC voltage: (0~900)V Level 1.5 6 Analog Pointer Meter Model 1729 AC current: (4~20)mA Level 1.5 7 Analog pointer meter model 3781 DC current: (0~50)mA Level 1.5 8 Analog pointer meter model 2451 AC current: (0~5)A Level 1.5 9 Analog pointer meter type 9541 AC current: (0~15)A Level 2.5

[0112] The main functions of this device are as follows:

[0113] This product has perfect protection function, it can automatically protect in case of voltage short circuit and current open circuit, and indicate the fault location;

[0114] The central control unit adopts STM32 microprocessor, which is powerful, reliable and easy to upgrade and maintain;

[0115] Equipped with large-capacity Flash ROM, it can store test data and export data through the USB interface;

[0116] Equipped with RS232 interface, it can realize program control function;

[0117] The database stores calibration output and automatically outputs calibration reports;

[0118] Automatically analyze the calibration interval of the equipment under test;

[0119] The accessory has a cable storage compartment, so the power cord and test cord can be carried with the instrument;

[0120] The interface is clear, the operation is simple, and the functions meet various application scenarios.

[0121] like Figure 1 As shown, the electrical instrument field calibration device consists of a main unit and a removable storage enclosure. The main unit is compact and easy to carry, while the storage enclosure is detachable. Compared to traditional reference sources, it is smaller and lighter, making it suitable for metrological calibration tasks such as equipment maintenance sites and field inspections. The product components are shown in the figure below.

[0122] The electrical instrument field calibration device can provide the output of various basic electrical quantities such as AC and DC voltage, AC, and DC current measurement functions. It can calibrate most low-precision analog pointer meters, digital multimeters, pointer multimeters, single-function measuring instruments, panel meters and other electrical measuring instruments.

[0123] The electrical instrument field calibration device includes DC voltage and current output, AC voltage and current output, and current sampling. Each component's functions are independent of each other, so during the design process, each function was divided into independent modules. This not only improves development efficiency but also prevents interference between module functions. The implementation of each module's functions is centrally coordinated and controlled by the system's central control unit.

[0124] The on-site calibration device for electrical instruments consists of a power supply unit, a main control board, an AC current board, a DC voltage board, an AC voltage board, a DC current board, a DC current sampling board, a touch display and an output regulator. The block diagram of the components is shown below. Figure 2 shown.

[0125] The field calibration device for electrical instruments has high performance indicators. To ensure the precision and accuracy requirements of its design, the system design introduces negative feedback closed-loop regulation technology. The closed-loop feedback design block diagram is as follows: Figure 3 shown.

[0126] The reference voltage serves as the basis for the DC voltage and current and AC voltage and current output modules, providing a reference voltage for the output of these modules; the programmable gain operational amplifier controls the size change of the output parameter to achieve a wide range of output; the feedback system composed of the feedback unit and comparator controls the precision and accuracy of the system output, allowing the system to output stable and accurate standard parameters.

[0127] like Figure 1 As shown, the output AC current and DC voltage range of the electrical instrument field calibration device is wide and the amplitude is high. The power supply system adopts AC 220V mains power, which is converted by the power circuit system to power the main control and various levels of circuit boards. The main control circuit system serves as the brain of the entire multi-functional calibration source, controlling and adjusting the work of each functional circuit board, and realizing communication with peripherals such as keyboard and display.

[0128] The power supply design for the electrical instrument field calibration device converts 220V AC power to power the various functional circuit boards. This 220V AC power is divided into three paths to power the entire device: one path is input to each circuit board, providing basic voltages of 5V, +12V, and ±15V; one path is used to generate a high voltage of 1000V, providing high voltage for the DC voltage board; and one path is used to generate a high current of 20A, providing high current for the DC current board. The power supply circuit design for each functional circuit board utilizes analog circuit acquisition. The analog circuit acquisition power supply should be powered by an LDO output power supply. Power supply isolation between the digital signal control section and the analog signal in the system should be ensured. This effectively minimizes the impact of the power supply chip on acquisition accuracy and improves system design stability. Because the circuit has a wide voltage and current range, with output voltages up to 1000V and currents reaching 20A, the overall system design requires electrical isolation between strong and weak currents to minimize interference between signals.

[0129] The central control unit (CCU) is the core of the electrical instrument field calibration system, controlling the entire system's operation and functionality. The microprocessor controller in the CCU is responsible for adjusting the DC voltage reference to an adjustable DC voltage reference, which serves as the basis for the output of DC voltage, DC current, AC current, and AC voltage. The master controller synthesizes DDS sinusoidal digital signals, adjusting the frequency, amplitude, and phase of the AC signal to achieve adjustable AC voltage and current output. The master controller controls the range of DC voltage, DC current, AC current, and AC voltage in the system, controlling the switching of the range relays to achieve different range adjustments. The master controller controls the acquisition rate and other parameters in the current sampling circuit to improve acquisition accuracy. The master controller manages the system's human-computer interaction, collects the system's keyboard status, and controls the system's required functions. It also displays operating status, progress, and system settings to the operator via a display screen, enhancing the practicality and convenience of system operation. The CCU also provides communication interfaces such as RS232 and USB.

[0130] The design principle of the DC standard voltage source is to provide a standard voltage from the reference voltage. The central control unit controls the generation of an adjustable DC voltage reference and amplifies this voltage to 0~10V through an operational amplifier. It can then be amplified further in this range to generate different voltage levels of 0~30V, 0~350V, 0~450V and 0~1000V.

[0131] The DC voltage source system is a closed-loop feedback system. The transfer function of the system is analyzed. The DC voltage reference can be processed according to the step response signal. The transfer function of the integrator is K / s, the transfer function of the operational amplifier is K0, and the transfer coefficient of the feedback circuit is β.

[0132]

[0133] When the operational amplifier's gain K0 is large and the negative feedback is deep enough, then:

[0134]

[0135] Where: U is the output voltage; E is the integrator input voltage; β is the negative feedback coefficient of the transfer function.

[0136] It can be seen from the formula that when the transfer function β and the input voltage are constant, the output voltage will not change, so the precision and accuracy of the output voltage are determined by the transfer function β and the input voltage.

[0137] The output DC power designed in this project is 0~1000V. Due to the large range width, in order to ensure the output accuracy, the range is divided into 5 gears: 75mV, 3V, 30V, 300V, and 1000V. In actual development, these gear designs are controlled by relays to achieve voltage gear switching.

[0138] The difference between DC current design and DC voltage design is that a transconductance amplifier is added after the operational amplifier in DC current to convert the output DC voltage into a DC current signal. Since the output end is the current physical quantity and the input end of the error analyzer is a voltage signal, after collecting the current I at the output end of the system, in the feedback stage, the collected DC current signal is first converted into a DC voltage signal, and the difference is made with the voltage E at the input end of the error analyzer to achieve feedback control.

[0139] A transconductance amplifier is a device that converts input voltage into current output. It is a voltage-controlled current type device that converts voltage into current output. The output current is directly proportional to the input voltage, and the output current size is independent of the load.

[0140] The DC current source system is similar to the DC voltage source system. The transfer function of the system is analyzed. The DC voltage reference can be processed according to the step response signal. The transfer function of the integrator is K / s, the transfer function of the operational amplifier is K0, and the input voltage and output current of the transconductance amplifier are proportional. The sensing function of the transconductance amplifier is K1, and the transfer coefficient of the feedback circuit is β.

[0141] Therefore, the transfer function of the DC current range is:

[0142]

[0143] When the amplification factor K0 of the operational amplifier is large and the negative feedback is deep enough, then:

[0144]

[0145] Where: U is the output voltage; E is the integrator input voltage; β is the negative feedback coefficient of the transfer function.

[0146] It can be seen from the formula that the current output of the DC current range is only related to the input voltage and transfer function.

[0147] In the design of AC voltage calibration source, since there is no chip in the current chip field that can generate stable and reliable AC voltage stabilization chip, the reference voltage in all AC voltage schemes still uses the DC voltage provided in the DC voltage scheme. Then, a DDS circuit is added to the DC voltage scheme to synthesize the output AC voltage signal. This ensures the precision and accuracy of the output AC voltage signal. Moreover, since the front-end input of the comparator is a DC voltage signal and the feedback voltage acquisition output is an AC voltage signal, it is necessary to add an AC-DC conversion circuit in the feedback circuit design, and filter the converted DC signal before inputting it into the front-end of the comparator.

[0148] The AC voltage source system adds DDS, AC / DC conversion circuit and filtering circuit compared to the DC voltage source system. The transfer function of the system is analyzed. The AC voltage reference can be processed according to the step response signal. The transfer function of the integrator is K / s, and the transfer function of the DDS circuit is The transfer function of the operational amplifier is K0, and the transfer coefficient of the feedback circuit is β.

[0149]

[0150] When the amplification factor K0 of the operational amplifier is large and the negative feedback is deep enough, then:

[0151]

[0152] Where: U is the output voltage; E is the integrator input voltage; β is the negative feedback coefficient of the transfer function.

[0153] It can be seen from the formula that when the transfer function β and the input voltage are constant, the output voltage will not change, so the precision and accuracy of the output voltage are determined by the transfer function β and the input voltage.

[0154] In AC current design, just like AC voltage, a DC voltage chip is required to generate a reliable and stable DC voltage. After being controlled by the main controller as an adjustable DC voltage reference, it is then passed through a transconductance amplifier to generate a DC current signal, which is synthesized with the DDS circuit to output an AC current signal. Finally, it is amplified by an operational amplifier to output a wide range of AC current signals.

[0155] The AC current source system is similar to the AC voltage source system. The transfer function of the system is analyzed. The DC voltage reference can be processed according to the step response signal. The transfer function of the integrator is K / s, and the transfer function of the DDS circuit is The transfer function of the operational amplifier is K0, while the input voltage and output current of the transconductance amplifier are proportional. The sensing function of the transconductance amplifier is K1, and the transfer coefficient of the feedback circuit is β.

[0156] Therefore, the transfer function of the AC current range is:

[0157]

[0158] When the amplification factor K0 of the operational amplifier is large and the negative feedback is deep enough, then:

[0159]

[0160] Where: U is the output voltage; E is the integrator input voltage; β is the negative feedback coefficient of the transfer function.

[0161] It can be seen from the formula that the current output of the DC current range is only related to the input voltage and transfer function.

[0162] Example 2

[0163] like Figure 4 As shown, an embodiment of the present invention further provides a calibration result optimization method for an on-site calibration device for an electrical instrument, comprising:

[0164] Step 101, obtaining voltage information and current information of an electrical instrument field calibration device, wherein the voltage information includes: voltage output and reference voltage, and the current information includes: current output and reference current;

[0165] Step 102, respectively setting a voltage output error calculation model and a current output error calculation model, and calculating the voltage output error and the current output error based on the voltage information and the current information;

[0166] Specifically, the voltage output error calculation model includes:

[0167]

[0168] The error calculation model of the current output includes:

[0169]

[0170] Among them, ∈ V (t) is the error of voltage output at time t, and the voltage output includes DC voltage output and AC voltage output, γ V (t) is the first adjustment factor of the error calculation model of the voltage output at time t, U measured is the voltage output, U std is a reference voltage, and the reference voltage includes: a reference DC voltage and a reference AC voltage, V (t) is the second adjustment factor of the error calculation model of the voltage output at time t, ∈ I (t) is the error of current output at time t, γ I(t) is the first adjustment factor of the error calculation model of the current output at time t, I measured is the current output, I std is the reference current, ζ I (t) is the second adjustment factor of the error calculation model of the current output at time t.

[0171] Step 103, respectively setting a feedback voltage calculation model and a feedback current calculation model, and calculating the feedback voltage and the feedback current according to the voltage output error and the current output error;

[0172] Specifically, the feedback voltage calculation model includes:

[0173]

[0174] The feedback current calculation model includes:

[0175]

[0176] Among them, U adjusted (t) is the feedback voltage at time t, δ V (t) is the first adjustment factor of the feedback voltage calculation model at time t, η V (t) is the second adjustment factor of the feedback voltage calculation model at time t, λ V is the third adjustment factor of the feedback voltage calculation model, I adjusted (t) is the feedback current at time t, δ I (t) is the first adjustment factor of the feedback current calculation model at time t, η I (t) is the second adjustment factor of the feedback current calculation model at time t, λ I It is the third adjustment factor of the feedback current calculation model.

[0177] Step 104 : respectively setting a voltage optimization objective function and a current optimization objective function, and combining the feedback voltage and the feedback current to minimize the voltage optimization objective function and the current optimization objective function to achieve voltage output and current output optimization.

[0178] Specifically, the voltage optimization objective function J used to optimize the voltage calibration is: V include:

[0179]

[0180] Current optimization objective function J for current calibration optimization I include:

[0181]

[0182] Where T′ is the time period, λ V is the first adjustment factor of the voltage optimization objective function, μ V is the second adjustment factor of the voltage optimization objective function, α V is the third adjustment factor of the voltage optimization objective function, β V is the fourth adjustment factor of the voltage optimization objective function, T(t) is the ambient temperature at time t, T0 is the reference temperature, γ V is the fifth adjustment factor of the voltage optimization objective function, H(t) is the ambient humidity at time t, H0 is the reference humidity, δ V is the sixth adjustment factor of the voltage optimization objective function, n is the seventh adjustment factor of the voltage optimization objective function, λ I is the first adjustment factor of the current optimization objective function, μ I The second adjustment factor of the current optimization objective function, α I is the third adjustment factor of the current optimization objective function, β I is the fourth adjustment factor of the current optimization objective function, γ I is the fifth adjustment factor of the current optimization objective function, δ I is the sixth adjustment factor of the current optimization objective function, and m is the seventh adjustment factor of the current optimization objective function.

[0183] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0184] In the above embodiments of the present invention, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0185] In the several embodiments provided by the present invention, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the system embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, and can be electrical or other forms.

[0186] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0187] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0188] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only storage medium (ROM, Read-Only Memory), random access storage medium (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk, etc. Various media that can store program codes.

[0189] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. An on-site calibration device for electrical instruments, characterized in that: include: A power supply unit, used to provide working power for the device; A central control unit, used to control the operation of the device; DC voltage output module, used to output DC voltage within the set range; DC current output module, used to output DC current within a set range; AC voltage output module, used to output AC voltage within the set range; AC current output module, used to output AC current within a set range; DC current sampling module, used to measure the DC current output by the device under test; Human-computer interaction module, including input devices and display devices, for user interaction; The modules are connected in series through the central control unit and are controlled and coordinated by the central control unit, and the modules and the central control unit are coupled to the power supply unit.

2. The on-site calibration device for electrical instruments according to claim 1, characterized in that: The DC voltage output module includes: A reference voltage source, used for providing a reference DC voltage; A programmable gain amplifier is used to amplify the reference DC voltage according to the set range; The feedback system is used to detect the DC voltage output and feed it back to the programmable gain amplifier to form a closed-loop control.

3. The on-site calibration device for electrical instruments according to claim 1, characterized in that: The DC current output module includes: A reference voltage source, used for providing a reference DC voltage; A programmable gain amplifier is used to amplify the reference DC voltage according to the set range; A transconductance amplifier, used to convert the amplified reference DC voltage into a corresponding DC current output; The feedback system is used to detect the DC current output and feed it back to the programmable gain amplifier to form a closed-loop control.

4. The on-site calibration device for electrical instruments according to claim 1, characterized in that: The AC voltage output module includes: Digital synthesizer, used to synthesize sinusoidal digital signals according to the set frequency, amplitude and phase; A digital-to-analog converter, configured to convert the sinusoidal digital signal into an analog sinusoidal signal; A programmable gain amplifier, configured to amplify the amplitude of the analog sine wave signal; The feedback system is used to detect the AC voltage output and feed it back to the programmable gain amplifier to form a closed-loop control.

5. The on-site calibration device for electrical instruments according to claim 1, characterized in that: The AC current output module includes: Digital synthesizer, used to synthesize sinusoidal digital signals according to the set frequency, amplitude and phase; A digital-to-analog converter, configured to convert the sinusoidal digital signal into an analog sinusoidal signal; A programmable gain amplifier, configured to amplify the amplitude of the sine wave signal; a transconductance amplifier, configured to convert the amplified sinusoidal wave signal into a corresponding alternating current output; The feedback system is used to detect the AC current output and feed it back to the programmable gain amplifier to form a closed-loop control.

6. The on-site calibration device for electrical instruments according to claim 1, characterized in that: The human-computer interaction module includes a keyboard, a display screen and a communication interface.

7. A calibration result optimization method for the electrical instrument field calibration device according to any one of claims 1 to 6, characterized in that: include: Acquire voltage information and current information of an electrical instrument field calibration device, wherein the voltage information includes: voltage output and reference voltage, and the current information includes: current output and reference current; respectively setting a voltage output error calculation model and a current output error calculation model, and calculating the voltage output error and the current output error based on the voltage information and the current information; respectively setting a feedback voltage calculation model and a feedback current calculation model, and calculating the feedback voltage and the feedback current according to the error of the voltage output and the error of the current output; The voltage optimization objective function and the current optimization objective function are set separately, and the feedback voltage and the feedback current are combined to complete the voltage output and current output optimization by minimizing the voltage optimization objective function and the current optimization objective function.

8. The calibration result optimization method of the electrical instrument field calibration device according to claim 7, characterized in that: The error calculation model of the voltage output includes: The error calculation model of the current output includes: Among them, ∈ V (t) is the error of voltage output at time t, and the voltage output includes DC voltage output and AC voltage output, γ V (t) is the first adjustment factor of the error calculation model of the voltage output at time t, U measured is the voltage output, U std is a reference voltage, and the reference voltage includes: a reference DC voltage and a reference AC voltage, V (t) is the second adjustment factor of the error calculation model of the voltage output at time t, ∈ I (t) is the error of current output at time t, γ I (t) is the first adjustment factor of the error calculation model of the current output at time t, I measured is the current output, I std is the reference current, ζ I (t) is the second adjustment factor of the error calculation model of the current output at time t.

9. The method for optimizing calibration results of an on-site calibration device for an electrical instrument according to claim 8, wherein: The feedback voltage calculation model includes: The feedback current calculation model includes: Among them, U adjusted (t) is the feedback voltage at time t, δ V (t) is the first adjustment factor of the feedback voltage calculation model at time t, η V (t) is the second adjustment factor of the feedback voltage calculation model at time t, λ V is the third adjustment factor of the feedback voltage calculation model, I adjusted (t) is the feedback current at time t, δ I (t) is the first adjustment factor of the feedback current calculation model at time t, η I (t) is the second adjustment factor of the feedback current calculation model at time t, λ I It is the third adjustment factor of the feedback current calculation model.

10. The calibration result optimization method of the electrical instrument field calibration device according to claim 9, characterized in that: Voltage optimization objective function J for voltage calibration optimization V include: Current optimization objective function J for current calibration optimization I include: Where T′ is the time period, λ V is the first adjustment factor of the voltage optimization objective function, μ V is the second adjustment factor of the voltage optimization objective function, α V is the third adjustment factor of the voltage optimization objective function, β V is the fourth adjustment factor of the voltage optimization objective function, T(t) is the ambient temperature at time t, T0 is the reference temperature, γ V is the fifth adjustment factor of the voltage optimization objective function, H(t) is the ambient humidity at time t, H0 is the reference humidity, δ V is the sixth adjustment factor of the voltage optimization objective function, n is the seventh adjustment factor of the voltage optimization objective function, λ I is the first adjustment factor of the current optimization objective function, μ I The second adjustment factor of the current optimization objective function, α I is the third adjustment factor of the current optimization objective function, β I is the fourth adjustment factor of the current optimization objective function, γ I is the fifth adjustment factor of the current optimization objective function, δ I is the sixth adjustment factor of the current optimization objective function, and m is the seventh adjustment factor of the current optimization objective function.

Images