CN210038002U - Voltage sag experiment platform - Google Patents

Abstract

The utility model relates to a voltage sag experiment platform, comprising: a voltage sag generating device, the output end of which is electrically connected with a device to be tested, and is used for outputting a corresponding voltage sag to the device to be tested according to a voltage sag signal; signal acquisition a device, which is arranged at the output end of the voltage sag generating device to collect the output voltage and output current of the voltage sag generating device; a state acquisition device, which is set corresponding to the device to be tested and used to collect the working state of the device to be tested; The main control device is used to output the voltage sag signal to the voltage sag generating device, and analyze the voltage sag sensitivity of the device to be tested according to the output voltage and output current of the voltage sag generator and the working state of the device to be tested. Therefore, the automatic test of the voltage sag sensitivity of the equipment can be realized, and the problem of a lot of manpower and material resources caused by manual experiments can be effectively solved.

Description

Voltage sag test platform

technical field

The utility model relates to the technical field of power quality, in particular to a voltage sag experiment platform.

Background technique

Inverter is a kind of equipment widely used in industrial production. During use, when the voltage sags in the power grid, the voltage on the DC side of the inverter will drop along with it, and when it drops to a certain level, the low-voltage protection will be triggered. And the tripping will cause the entire industrial process to be interrupted, which may cause huge losses to the economy and bring safety hazards to human life.

In recent years, with the continuous access of nonlinear and impact loads, the power quality problem in the power grid has become increasingly serious, and the voltage sag problem has become the most serious power quality problem that the power supply department and power users are highly concerned about. Usually, most of the voltage sags in the power system are caused by short-circuit faults, and the voltage sags caused by various types of short-circuit faults are mainly divided into three categories after being propagated through transformers and lines, namely three-phase sags and two-phase sags. and single-phase sag. However, the tolerance of inverters under different types of sags is quite different. It is most sensitive to three-phase sags, followed by two-phase sags and single-phase sags. Some inverters are even sensitive to two-phase sags. Dips and monophasic dips are immune.

Researching the withstand characteristics of inverters under different types of sags is the basis for analyzing the voltage sag tolerance and sag suppression of inverters. Therefore, relevant research has been gradually carried out in China. However, at present, most of the relevant domestic researches are aimed at the frequency converters of the auxiliary machines of thermal power plants, and mainly focus on measures to improve the low voltage ride-through capability. Voltage sag experiments are all manual experiments, which require a lot of manpower and material resources.

Utility model content

Based on this, it is necessary to provide a voltage sag test platform for the problem of manpower and material resource consumption caused by a large number of manual experiments in the process of researching and testing the voltage sag tolerance characteristics of the equipment to be tested, such as frequency converters. .

A voltage sag experiment platform, comprising:

a voltage sag generating device, the output end of the voltage sag generating device is electrically connected with the equipment to be tested, and is used for outputting the corresponding voltage sag to the equipment to be tested according to the voltage sag signal;

a signal acquisition device, the signal acquisition device is arranged at the output end of the voltage sag generation device to collect the output voltage and output current of the voltage sag generation device;

A state acquisition device, the state acquisition device is set corresponding to the device to be tested and used to collect the working state of the device to be tested;

The main control device, the main control device is electrically connected with the voltage sag generation device, the signal acquisition device and the state acquisition device, respectively, for outputting the voltage sag signal to the voltage sag generation device, and according to the output voltage of the voltage sag generation device and the state acquisition device. The output current and the working state of the device under test are analyzed for the voltage sag sensitivity of the device under test.

In one of the embodiments, the device under test is a frequency converter under test.

In one of the embodiments, the voltage sag generating device includes:

DC capacitor, the DC capacitor is electrically connected between the output terminals of the DC power supply;

an inverter circuit, the input end of the inverter circuit is electrically connected with the DC capacitor, and the control end of the inverter circuit is electrically connected with the main control device, so as to convert the DC power output by the DC power supply into a voltage sag according to the voltage sag signal;

A filter circuit, the input end of the filter circuit is electrically connected to the output end of the inverter circuit, and the output end of the filter circuit is electrically connected to the device to be tested, so as to filter the voltage sag and transmit the filtered voltage sag. to the device under test.

In one embodiment, the signal acquisition device includes a voltage signal acquisition unit and a current signal acquisition unit, wherein the voltage signal acquisition unit includes: a voltage acquisition and conditioning circuit and a voltage data acquisition circuit, and the voltage acquisition and conditioning circuit is used to acquire the occurrence of voltage sags the output voltage of the device and output the first analog signal, and the voltage data acquisition circuit is used to convert the first analog signal into the first digital signal and output it to the main control device;

The current signal acquisition unit includes: a current acquisition and conditioning circuit and a current data acquisition circuit, the current acquisition and conditioning circuit is used to collect the output current of the voltage sag generator and output a second analog signal, and the current data acquisition circuit is used to convert the second analog signal. The second digital signal is output to the main control device.

In one embodiment, the voltage acquisition and conditioning circuit includes:

voltage transformer, the voltage transformer is arranged at the output end of the voltage sag generating device to collect the output voltage of the voltage sag generating device and output the first analog signal;

a first isolation circuit, which is electrically connected to the voltage transformer for following the first analog signal and isolating the first analog signal;

The first voltage stabilizer circuit is electrically connected to the first isolation circuit for stabilizing the first analog signal within the range of the first preset analog signal.

In one embodiment, the current acquisition and conditioning circuit includes:

Current transformer, the current transformer is arranged at the output end of the voltage sag generating device to collect the output current of the voltage sag generating device and output the second analog signal;

a second isolation circuit, the second isolation circuit is electrically connected to the current transformer for following the second analog signal and isolating the second analog signal;

The second voltage stabilizer circuit is electrically connected to the second isolation circuit for stabilizing the second analog signal within the range of the second preset analog signal.

In one embodiment, the DC power supply includes: a rectifier circuit, the rectifier circuit is electrically connected to the AC power supply and the voltage sag generating device, respectively, and is used to convert the AC power output by the AC power supply into DC power.

In one embodiment, the above-mentioned platform further includes:

a first switch, the first switch is arranged between the DC power supply and the voltage sag generating device, and is used to control the conduction and disconnection of the DC power supply and the voltage sag generating device;

a second switch, the second switch is arranged between the voltage sag generating device and the device to be tested, and is used to control the on and off of the voltage sag generating device and the device to be tested;

The third switch, the third switch is arranged between the AC power supply and the device to be tested, and is used to control the conduction and disconnection between the AC power supply and the device to be tested.

In one embodiment, the above-mentioned platform further includes: a start-up control device, the signal input end of the start-up control device is electrically connected to the main control device, and the mechanical output end of the start-up control device corresponds to the start-up switch setting of the device under test, so as to be used according to the The start-up signal output by the main control device controls the start-up of the device under test.

In one embodiment, the activation control device includes:

a motion control unit, the motion control unit is electrically connected with the main control device, and is used for outputting a pulse signal according to a start signal output by the main control device;

a motor drive unit, the motor drive unit is electrically connected with the motion control unit for outputting the drive signal according to the pulse signal;

a motor, the motor is electrically connected with the motor drive unit to rotate according to the drive signal;

The sliding table is mechanically connected with the motor and the operating rod, respectively, and is used to control the movement of the operating rod under the driving of the motor, so as to control the startup of the equipment to be tested.

The above-mentioned voltage sag experimental platform outputs the corresponding voltage sag to the device to be tested through the voltage sag generation device according to the voltage sag signal output by the main control device, and collects the output voltage and output of the voltage sag generation device through the signal acquisition device. The main control device analyzes the voltage sag sensitivity of the device under test according to the output voltage and output current of the voltage sag generator and the working state of the device under test. Therefore, the automatic test of the voltage sag sensitivity of the equipment can be realized through the experimental platform, which effectively solves the problem of a lot of manpower and material resources caused by manual experiments.

Description of drawings

1 is a schematic structural diagram of a voltage sag test platform in one embodiment;

2 is a circuit topology diagram of a voltage sag generating device in one embodiment;

3 is a circuit diagram of a voltage acquisition and conditioning circuit in one embodiment;

4 is a circuit diagram of a current acquisition and conditioning circuit in one embodiment;

5 is a schematic structural diagram of a voltage sag test platform in another embodiment;

6 is a schematic structural diagram of a voltage sag test platform in yet another embodiment;

7 is a schematic structural diagram of a start-up control device in one embodiment;

FIG. 8 is a schematic diagram of the installation position of the stepping motor in one embodiment.

Detailed ways

In order to make the above objects, features and advantages of the present utility model more clearly understood, the specific embodiments of the present utility model are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present utility model can be implemented in many other ways different from those described here, and those skilled in the art can make similar improvements without violating the connotation of the present utility model. Therefore, the present utility model is not limited by the specific implementation disclosed below. .

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The technical features of the above embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features It is considered to be the range described in this specification.

FIG. 1 is a schematic structural diagram of a voltage sag experiment platform in one embodiment. As shown in FIG. 1 , the voltage sag experiment platform includes: a voltage sag generation device 10 , a signal acquisition device 20 , a state acquisition device 30 and a main control device 40 . .

Wherein, the output end of the voltage sag generating device 10 is electrically connected to the device to be tested 50 for outputting a corresponding voltage sag to the device to be tested 50 according to the voltage sag signal; the signal acquisition device 20 is arranged on the voltage sag generating device 10 The output terminal of the device is used to collect the output voltage and output current of the voltage sag generation device 10; the state acquisition device 30 is set corresponding to the device under test 50 to collect the working state of the device under test 50; the main control device 40 and the voltage sag The generating device 10 , the signal collecting device 20 and the state collecting device 30 are respectively electrically connected for outputting a voltage sag signal to the voltage sag generating device 10 , and according to the output voltage and output current of the voltage sag generating device 10 and the equipment to be tested The working state of 50 is to analyze the voltage sag sensitivity of the device under test 50 . Wherein, the device under test 50 may be an inverter under test.

Specifically, referring to FIG. 1 , the voltage sag generating device 10 can output a corresponding voltage to the device under test 50 (eg, a frequency converter) according to the voltage control signal output by the main control device 40 . For example, when the main control device 40 outputs a voltage normal signal to the voltage sag generating device 10, the voltage sag generating device 10 will output a stable voltage to the device under test 50 according to the voltage normal signal, and the output stable voltage is consistent with the voltage to be tested. The rated working voltage of the equipment 50 is consistent, such as 220V/380V AC voltage; when the main control device 40 outputs a voltage sag signal to the voltage sag generator 10, the voltage sag generator 10 will output the corresponding voltage sag signal according to the voltage sag signal. A single voltage sag or continuous voltage sag, and the initial phase, sag depth, and sag duration of the single voltage sag or continuous voltage sag correspond to the voltage sag signal, that is, the voltage sag The generating device 10 can output a single voltage sag or a continuous voltage sag of any initial phase, any sag depth, and any sag duration according to the set parameters, so as to facilitate the test of different voltage sags, and thus facilitate the realization of different voltage sags. Tests for the type of equipment under test.

The signal collecting device 20 is arranged at the output end of the voltage sag generating device 10 , and can collect the output voltage and output current of the voltage sag generating device 10 in a contact or non-contact manner, and transmit them to the main control device 40 . The state acquisition device 30 is set at the working indicator light of the device under test 50 to collect the color of the working indicator light, accurately and sensitively identify the color of the working indicator light, and output the corresponding working state to the main controller according to the identification result. The device 40 is used for subsequent analysis. For example, under normal circumstances, when the working indicator light is green, it indicates that the device under test 50 is in a normal working state, and when it is red, it indicates that the device under test 50 is in a fault state. The actual situation is determined, and there is no restriction here. The main control device 40 has built-in corresponding software and is operated by the user, which can be used to set the rated working voltage of the device under test 50 and the working parameters of the voltage sag, etc., and coordinate the efficient operation of each device, and can process the collected voltage, current and working state at the same time. and other data to perform voltage sag sensitivity analysis on the device under test 50, wherein the main control device 40 may be a personal computer.

During the test, the user can first control the main control device 40 to output a voltage normal signal to the voltage sag generator 10, and the voltage sag generator 10 outputs a stable voltage to the equipment under test 50 according to the voltage normal signal to detect the voltage sag generator 10. Whether the test equipment 50 can work normally under the normal power supply state, if not, replace the equipment to be tested 50 and re-test; if it can work normally, record the output voltage of the voltage sag generator 10 collected by the signal acquisition device 20 and output current, and at the same time record the working state of the device under test 50 collected by the state collecting device 30 as a reference value when the voltage sags.

Then, the main control device 40 is controlled to output a voltage sag signal to the voltage sag generating device 10. The voltage sag signal may include a voltage sag trigger signal and the initial phase, sag depth, sag duration, and sag of the voltage sag. In this case, the voltage sag generator 10 outputs the corresponding voltage sag to the equipment under test 50 according to the voltage sag signal, so that the equipment under test 50 works under the voltage sag, while the main The control device 40 records the output voltage and output current of the voltage sag generator 10 collected by the signal collecting device 20, and the working state of the equipment under test 50 collected by the state collecting device 30, and records the voltage, current and The working state and the voltage, current and working state under the voltage sag are analyzed for the voltage sag sensitivity (eg tolerance) of the device under test 50, and the corresponding analysis result is output.

In this embodiment, the voltage sag generating device outputs the corresponding voltage sag signal to the device to be tested according to the voltage sag signal output by the main control device, and the signal acquisition device collects the output voltage and output current of the voltage sag generating device, And collecting the working state of the device under test through the state acquisition device, the main control device analyzes the voltage sag sensitivity of the device under test according to the output voltage and output current of the voltage sag generating device and the working state of the device under test. Therefore, the automatic test of the voltage sag sensitivity of the equipment can be realized, and the problem of a large amount of manpower and material resources caused by manual experiments can be effectively solved.

In one embodiment, the voltage sag generating device 10 includes: a DC capacitor 11 , an inverter circuit 12 and a filter circuit 13 , wherein the DC capacitor 11 is electrically connected between the output terminals of the DC power source 60 ; the input of the inverter circuit 12 The terminal is electrically connected to the DC capacitor 11, and the control terminal of the inverter circuit 12 is electrically connected to the main control device 40 to convert the DC power output by the DC power supply 60 into a voltage sag according to the voltage sag signal; the input terminal of the filter circuit 13 is connected to the voltage sag signal. The output end of the inverter circuit 12 is electrically connected, and the output end of the filter circuit 13 is electrically connected to the device under test 50 for filtering the voltage sag and transmitting the filtered voltage sag to the device under test 50 .

Specifically, referring to FIG. 2 , the DC capacitor 11 may be composed of a plurality of capacitors connected in series. For example, the DC capacitor 11 may include a first DC capacitor C _d1 and a second DC capacitor C _d2 connected in series, wherein the first DC capacitor C One end of _d1 is electrically connected to one end of the DC power supply 60, the other end of the first DC capacitor C _d1 is electrically connected to one end of the second DC capacitor C _d2 and the connection point is taken as the center line N, and the other end of the second DC capacitor C _d2 is electrically connected to one end of the second DC capacitor C d2. The other end of the DC power source 60 is electrically connected.

The inverter circuit 12 may be a midpoint clamped three-level inverter circuit, and may specifically include a first bridge arm 121 , a second bridge arm 122 and a third bridge arm 123 , and the first bridge arm 121 , the second bridge arm 121 , and the second bridge arm 123 . 122 and the third bridge arm 123 have the same structure. The first bridge arm 121 may include first to fourth switch transistors S _a1 to S _a4 , a first diode D _a1 and a second diode D _a2 , and the first end of the first switch S _a1 is connected to the One end of the first DC capacitor C _d1 is electrically connected, the second end of the first switch S _a1 is electrically connected to the first end of the second switch S _a2 , and the second end of the second switch S a2 is electrically connected to the third switch S _a2 The first end of S _a3 is electrically connected, the second end of the third switch S _a3 is electrically connected to the first end of the fourth switch S _a4 , and the second end of the fourth switch S _a4 is electrically connected to the second end of the second capacitor C _d2 The other end is electrically connected, and the control ends of the first switch tube S _a1 to the fourth switch tube S _a4 are respectively electrically connected to the main control device 40; the cathode of the first diode D _a1 is connected between the first switch tube S _a1 and the third switch tube S a1. Between the two switches S _a2 , the anode of the first diode D _a1 and the cathode of the second diode D _a2 and the connection points between the other end of the first DC capacitor C _d1 and one end of the second DC capacitor C _d2 are respectively For electrical connection, the anode of the second diode D _a2 is connected between the third switch tube S _a3 and the fourth switch tube S _a4 . Since the structures of the first bridge arm 121 , the second bridge arm 122 and the third bridge arm 123 are the same, the structure description of the second bridge arm 122 and the third bridge arm 123 may refer to the structure description of the first bridge arm 121 . The details will not be repeated here.

The filter circuit 13 may be an LCL type filter circuit, and may specifically include a first filter circuit 131, a second filter circuit 132, and a third filter circuit 133, and the first filter circuit 131, the second filter circuit 132, and the third filter circuit 133. The structure is the same. The first filter circuit 131 includes a first inductor L ₁₁ , a second inductor L ₁₂ and a first capacitor C ₁ , and one end of the first inductor L ₁₁ is electrically connected to the first bridge arm 121 , specifically to the second switch tube S _a2 The second end of the first inductance L11 is electrically connected to the connection point of the first end of the third switch tube S _a3 , the other end of the first inductance L11 is electrically connected to one end of the second inductance _L12 , and the other end _of the second inductance _L12 is electrically connected to the One end of the device under test 50 is electrically connected, and the other end of the device under test 50 is electrically connected to the neutral line N; one end _of the first capacitor _C1 is electrically connected to the other end of the first inductor _L11 and one end of the second inductor L12, respectively , the other end of the first capacitor _C1 is electrically connected to the second capacitor C2 of the _second filter circuit 132 and the third capacitor C3 of the _third filter circuit 133, respectively. Since the structures of the first filter circuit 131, the second filter circuit 132 and the third filter circuit 133 are the same, for the description of the structures of the second filter circuit 132 and the third filter circuit 133, reference may be made to the description of the structure of the first filter circuit 131. The details will not be repeated here.

When the voltage sag generating device 10 is working, the voltage sag generating device 10 can control the voltage of the output terminal according to the voltage control signal output by the main control device 40 by using the voltage outer loop control method, so that the voltage of the output terminal can track the voltage control signal. Wherein, when the voltage control signal is the voltage normal signal, according to the voltage normal signal, by controlling the on and off of the switch tube in the inverter circuit 12, the direct current output by the direct current power supply 60 can be inverted into a stable alternating current (eg 220V/380V alternating current), and is filtered by the filter circuit 13 and provided to the device under test 50 for standard voltage testing; when the voltage control signal is a voltage sag signal, the inverter circuit 12 is controlled according to the voltage sag signal. The conduction and disconnection of the switch tube in the DC power supply 60 can invert the DC power output by the DC power supply 60 into a single voltage sag or a continuous voltage sag with a certain sag depth, and provide it to the waiting device after being filtered by the filter circuit 13. test equipment 50 for voltage sag testing.

It should be noted that, in the example shown in FIG. 2 , the inverter circuit 12 adopts a neutral-point clamped three-level inverter circuit. Since the inverter circuit can output a three-phase voltage with adjustable voltage, it can It can supply power to one three-phase input device under test (such as three-phase input inverter), and can also supply power to three single-phase input device under test (such as single-phase input inverter) at the same time. Wherein, when the device to be tested 50 is a three-phase input device to be tested, the voltage sag test can be performed on the three-phase input device to be tested; when the device to be tested 50 is a single-phase input device to be tested, a single-phase input device to be tested can be tested. The voltage sag test of the phase input device under test can also realize the voltage sag test of any combination of three single-phase input devices under test, and the test can be selected according to actual needs. Of course, in practical applications, the inverter circuit 12 can also adopt other circuit structures. Circuits, etc., select the settings according to the actual needs, and there are no restrictions here.

In one embodiment, the signal acquisition device 20 includes a voltage signal acquisition unit and a current signal acquisition unit, wherein the voltage signal acquisition unit includes: a voltage acquisition and conditioning circuit and a voltage data acquisition circuit, and the voltage acquisition and conditioning circuit is used to acquire the occurrence of voltage sags The device 10 outputs a voltage and outputs a first analog signal, and the voltage data acquisition circuit is used to convert the first analog signal into a first digital signal and output it to the main control device 40 .

Further, as shown in FIG. 3 , the voltage acquisition and conditioning circuit includes: a voltage transformer 211 , a first isolation circuit 212 and a first voltage regulator circuit 213 , wherein the voltage transformer 211 is arranged at the output end of the voltage sag generating device 10 , used to collect the output voltage of the voltage sag generator 10 and output the first analog signal; the first isolation circuit 212 is electrically connected to the voltage transformer 211 to follow the first analog signal and isolate the first analog signal; A voltage stabilizing circuit 213 is electrically connected to the first isolation circuit 212 for stabilizing the first analog signal within a first predetermined analog signal range.

Specifically, the voltage acquisition and conditioning circuit is electrically connected to the output end of the voltage sag generation device 10, and can be specifically composed of a voltage transformer 211 and its peripheral circuits to detect the output voltage waveform of the voltage sag generation device 10, and the voltage data acquisition The circuit is electrically connected to the voltage acquisition and conditioning circuit and the main control device 40 respectively, and is used to convert the analog signal of the output voltage obtained by the voltage acquisition and conditioning circuit into a digital signal, and transmit it to the main control device 40 through a data line (such as a USB line).

Specifically, the voltage acquisition and conditioning circuit may include a voltage transformer 211, a first isolation circuit 212 and a first voltage regulator circuit 213, wherein the voltage transformer 211 may be a Hall voltage sensor with a model of CLSM-10mA. Output linearization, high precision, fast response, strong anti-interference ability and can be applied to DC, AC or other arbitrary waveform characteristics, so it can meet the requirements of measuring voltage sag waveform. During the actual test, the first input end Ux of the voltage transformer 211 can be electrically connected to the phase to be measured (eg phase A, phase B or phase C) of the voltage sag generator 10 through the first resistor R1, and the second input The terminal Un is electrically connected to the neutral line N of the voltage sag generation device 10 , the output terminal MUx is grounded through the second resistor R2 and is electrically connected to the first isolation circuit 212 , and the voltage sag generation device 10 is collected in real time through the voltage transformer 211 and output the corresponding first analog signal to the first isolation circuit 212 .

The first isolation circuit 212 is mainly used for voltage follow-up and isolation, and specifically may be a voltage follower composed of a first operational amplifier K1, a third resistor R3 and a fourth resistor R4. The positive input terminal of the first operational amplifier K1 is electrically connected to one end of the third resistor R3, and the other end of the third resistor R3 is electrically connected to the output terminal MUx of the voltage transformer 211; the negative input terminal of the first operational amplifier K1 is electrically connected to the output terminal MUx of the voltage transformer 211. One end of the fourth resistor R4 is electrically connected; the output end of the first operational amplifier K1 is electrically connected to the other end of the fourth resistor R4, and is electrically connected to the first voltage regulator circuit 213 through the fifth resistor R5. Through the first isolation circuit 212 , the follow-up of the first analog signal output by the voltage transformer 211 and the isolation of high and low voltages can be achieved. The model of the first operational amplifier K1 may be OP4277 or the like, which is not specifically limited here.

The first voltage regulator circuit 213 is mainly used to stabilize the first analog signal between the first preset analog signal range, and specifically may include a first voltage regulator diode WY1 and a second voltage regulator diode WY2, wherein the first voltage regulator diode WY1 The anode of WY1 is electrically connected to the fifth resistor R5 and the voltage data acquisition circuit (not shown in the figure), respectively, the cathode of the first Zener diode WY1 is electrically connected to the cathode of the second Zener diode WY2, and the cathode of the second Zener diode WY2 is electrically connected. Anode ground GND. The first voltage regulator circuit 213 can stabilize the first analog signal output by the first isolation circuit 212 within the first preset analog signal range, such as -5V to +5V, so as to prevent the voltage of the output analog signal from being too high. The voltage data acquisition circuit is damaged when it collects too high voltage.

Further, the above-mentioned voltage acquisition and conditioning circuit may further include: a filter circuit 214, the filter circuit 214 may be an RC filter circuit formed by the sixth resistor R6 and the fourth capacitor C4 in parallel, through which the first isolation circuit can be The first analog signal output by 212 is filtered to ensure the stability of the first analog signal, thereby ensuring the reliability of output voltage data collection.

The voltage data acquisition circuit can be a data acquisition card with a model of smacq USB-4250, through which the voltage data acquisition circuit converts the first analog signal output by the voltage acquisition and conditioning circuit into a first digital signal, and passes through a data cable (such as a USB cable) transmitted to the main control device 40 .

In one embodiment, the current signal acquisition unit includes: a current acquisition and conditioning circuit and a current data acquisition circuit. The current acquisition and conditioning circuit is used to acquire the output current of the voltage sag generator 10 and output the second analog signal. The current data acquisition circuit uses The second analog signal is converted into a second digital signal and output to the main control device 40 .

Further, as shown in FIG. 4 , the current acquisition and conditioning circuit includes: a current transformer 221 , a second isolation circuit 222 and a second voltage regulator circuit 223 , wherein the current transformer 221 is arranged at the output end of the voltage sag generating device 10 , used to collect the output current of the voltage sag generator 10 and output the second analog signal; the second isolation circuit 222 is electrically connected to the current transformer 221 to follow the second analog signal and isolate the second analog signal; the first The two voltage-stabilizing circuits 223 are electrically connected to the second isolation circuit 222 for stabilizing the second analog signal within a second predetermined analog signal range.

Specifically, the current acquisition and conditioning circuit is electrically connected to the output end of the voltage sag generation device 10, and can be specifically composed of a current transformer 221 and its peripheral circuits to detect the output current waveform of the voltage sag generation device 10, and the current data acquisition The circuit is electrically connected to the current acquisition and conditioning circuit and the main control device 40 respectively, and is used to convert the analog signal of the output current obtained by the current acquisition and conditioning circuit into a digital signal, and transmit it to the main control device 40 through a data line (such as a USB line).

Specifically, the current acquisition and conditioning circuit may include a current transformer 221, a second isolation circuit 222 and a second voltage regulator circuit 223, wherein the current transformer 221 may be a Hall current sensor with a model of LA100-P. The characteristics of high accuracy, small temperature drift, fast response speed and frequency bandwidth can meet the requirements of measuring voltage sag waveforms. During the actual test, the current transformer 221 passes through the phase to be measured (such as phase A, phase B or phase C) of the voltage sag generating device 10 , and the output terminal MIx is grounded through the seventh resistor R7 and is connected to the second isolation circuit 222 Electrically connected, the current transformer 221 collects the output current waveform of the voltage sag generator 10 in real time, and outputs the corresponding second analog signal to the second isolation circuit 222 .

The second isolation circuit 222 is mainly used for voltage follow-up and isolation, and specifically may be a voltage follower formed by the second operational amplifier K2, the eighth resistor R8 and the ninth resistor R9. The positive input terminal of the second operational amplifier K2 is electrically connected to one end of the eighth resistor R8, and the other end of the eighth resistor R8 is electrically connected to the output terminal MIx of the current transformer 221; the negative input terminal of the second operational amplifier K2 is electrically connected to the output terminal MIx of the current transformer 221. One end of the ninth resistor R9 is electrically connected; the output end of the second operational amplifier K2 is electrically connected to the other end of the ninth resistor R9, and the output end of the second operational amplifier K2 is grounded through the tenth resistor R10 and is connected to the second voltage regulator circuit 223 electrical connections. Through the second isolation circuit 222 , the follow-up of the second analog signal output by the current transformer 221 and the isolation of high and low voltages can be achieved. The model of the second operational amplifier K2 may be OP4277, etc., which is not specifically limited here.

The second voltage regulator circuit 223 is mainly used to stabilize the second analog signal between the second preset analog signal range, and specifically may include a third voltage regulator diode WY3 and a fourth voltage regulator diode WY4, wherein the third voltage regulator diode WY4 The anode of WY3 is electrically connected to the output end of the second operational amplifier K2 and the current data acquisition circuit (not shown in the figure), respectively, the cathode of the third Zener diode WY3 is electrically connected to the cathode of the fourth Zener diode WY4, and the fourth Zener diode WY4 is electrically connected. The anode of the voltage diode WY4 is grounded to GND. The second voltage regulator circuit 223 can stabilize the second analog signal output by the second isolation circuit 222 within the second preset analog signal range, such as -5V to +5V, so as to prevent the voltage of the output analog signal from being too high. The current data acquisition circuit is damaged when collecting too high voltage.

The current data acquisition circuit can be a data acquisition card with a model of smacq USB-4250, through which the current data acquisition circuit converts the second analog signal output by the current acquisition and conditioning circuit into a second digital signal, and passes through a data cable (such as a USB cable) transmitted to the main control device 40 .

It should be noted that, in practical applications, the number of voltage signal acquisition units and current signal acquisition units may be determined according to the number of voltage phases output by the inverter circuit 12 . For example, when the inverter circuit 12 is a single-phase inverter circuit, the circuit only outputs one phase voltage, and only tests one single-phase input device under test, so a voltage signal acquisition unit and a current signal acquisition unit are set at this time. unit. When the inverter circuit 12 is a mid-point clamped three-level inverter circuit shown in FIG. 2 , the inverter circuit can output three-phase voltages, which are the voltages of the A-phase, the B-phase and the C-phase respectively, and can be used for one The three-phase input DUT or the combination of three single-phase input DUTs are tested, so at this time, a voltage signal acquisition unit and a current signal acquisition unit are set for each phase to detect the output voltage and output current of each phase. In addition, a corresponding voltage signal acquisition unit and a current signal acquisition unit may also be set to collect the voltage and current on the neutral line N for subsequent analysis, and the settings may be selected according to actual conditions.

In one embodiment, as shown in FIG. 5 , the DC power source 60 may include a rectifier circuit, and the rectifier circuit is electrically connected to the AC power source AC and the voltage sag generating device 10, respectively, for converting the AC power output by the AC power source AC into DC power, The voltage sag generating device 10 is powered. Among them, when the AC power supply AC is 220V/380V three-phase AC power supply, the corresponding rectifier circuit can be a three-phase uncontrollable rectifier bridge; when the AC power supply AC is 220V/380 single-phase AC power supply, the corresponding rectifier circuit can be a single-phase AC power supply. The phase uncontrollable rectifier bridge can be selected and set according to the actual situation, which is not limited here.

In one embodiment, continuing to refer to FIG. 5 , the above-mentioned voltage sag experiment platform further includes: a first switch S1, a second switch S2 and a third switch S3, wherein the first switch S1 is set between the DC power supply 60 and the DC power supply 60 and the third switch S3. Between the voltage sag generating device 10, it is used to control the conduction and disconnection of the DC power supply 60 and the voltage sag generating device 10; the second switch S2 is arranged between the voltage sag generating device 10 and the equipment under test 50, and is used for To control the on and off of the voltage sag generating device 10 and the device under test 50; the third switch S3 is arranged between the AC power source AC and the device under test 50 to control the connection between the AC power source AC and the device under test 50 turn-on and turn-off.

Specifically, as can be seen from the foregoing description, when the voltage sag test is performed, the main control device 40 is first controlled to output a voltage normal signal to the voltage sag generator 10, so that the voltage sag generator 10 outputs a stable voltage to the test. The device 50 is used to detect whether the device to be tested 50 can work normally under the normal power supply state, and collect the corresponding output voltage, output current and working state when it can work normally, as a reference value when the voltage sags. In practical applications, in addition to the above methods, it can also be achieved by setting corresponding switches and reasonably controlling the switches.

Specifically, as shown in FIG. 5 , when testing, the signal acquisition device 20 can be connected to the output end of the voltage sag generation device 10 first, and the signal acquisition device 20 can be connected to the output terminal of the voltage sag generator 10 through a data cable (such as a USB cable). The main control device 40 is electrically connected for data communication, and at the same time, the probe of the state acquisition device 30 is aligned with the working indicator light of the device under test 50, and the state acquisition device 30 and the main control device 40 are connected through a data cable (such as a USB cable). Electrically connected for data communication. Then, the standard voltage experiment is started. At this time, the first switch S1 and the second switch S2 are controlled to keep the open state, and the third switch S3 is controlled to be closed. Since the third switch S3 is in the closed state, the AC power supply AC will be directly supplied to the standby state. The test equipment 50 is powered to detect whether the test equipment 50 can work normally under the normal power supply state. If it cannot work normally, replace the test equipment 50; if it can work normally, record the output of the AC power supply AC through the main control device 40 The voltage and output current as well as the working state of the device under test 50 are used as reference values when the voltage sags.

Next, the voltage sag experiment is started, at this time, the third switch S3 is controlled to be turned off, and the first switch S1 and the second switch S2 are controlled to be turned on. Since the first switch S1 and the second switch S2 are in the closed state, the alternating current power source AC starts to supply power to the direct current power source 60 and the voltage sag generating device 10, and the voltage sag generating device 10 is powered on and enters the standby state. At this time, the main control device 40 can send a voltage sag signal to the voltage sag generator 10, the voltage sag generator 10 outputs the corresponding voltage sag according to the voltage sag signal, and the main control device 40 records the voltage sag generator. The output voltage and output current of 10 and the working state of the device under test 50 are compared with the reference values obtained in the standard voltage experiment to obtain the voltage sag sensitivity of the device under test 50 .

It can be understood that the voltage sag experiment can be repeated for many times to test the output voltage, output current and working state under different voltage sags, so as to realize the sensitivity test under different voltage sags. For example, the main control device 40 may send different voltage sag signals to the voltage sag generating device 10 at regular intervals, and simultaneously collect the corresponding output voltage, output current and working state for different voltage sag sensitivity tests.

In one embodiment, as shown in FIG. 6 , the above-mentioned voltage sag experiment platform further includes: a start-up control device 70 , the signal input end of the start-up control device 70 is electrically connected to the main control device 40 , and the mechanical output of the start-up control device 70 is electrically connected. The terminal corresponds to the setting of the startup switch of the device under test 50 , and is used to control the startup of the device under test 50 according to the startup signal output by the main control device 40 .

That is to say, the user can output the corresponding startup control signal to the startup control device 70 through the main control device 40, and realize the startup of the device under test 50 during the voltage sag test through the startup control device 70, thereby effectively guaranteeing the user during the test process. security.

In one embodiment, as shown in FIG. 7 , the starting control device 70 includes: a motion control unit 71 , a motor driving unit 72 , a motor 73 , a sliding table 74 and an operating lever 75 , wherein the motion control unit 71 and the main control device 40 The electrical connection is used to output the pulse signal according to the starting signal output by the main control device 40; the motor driving unit 72 is electrically connected to the motion control unit 71 to output the driving signal according to the pulse signal; the motor 73 is electrically connected to the motor driving unit 72 to use The slide table 74 is mechanically connected with the motor 73 and the operating rod 75 respectively, and is used to control the operation of the operating rod 75 under the driving of the motor 73 to control the device under test 50 to start.

Specifically, the starting control device 70 may be composed of a motion control unit 71, a motor driving unit 72, a motor 73, a sliding table 74 and an operating rod 75 connected in sequence. The motor driving unit 72 and the motor 73 can be powered by a 24V switching power supply, and the motion control unit 71 also communicates with the main control device 40 to output corresponding pulse signals to the motor driving unit 72 according to the operation signal sent by the main control device 40 . , the motor drive unit 72 outputs the corresponding motor drive signal to the motor 73 according to the frequency of the pulse signal, so as to drive the motor 73 to rotate at a certain angle, when the motor 73 rotates, the slide table 74 can be controlled to move, thereby automatically operating the device under test 50. For example, by controlling the sliding table 74 to move, the operating lever 75 drives the start switch of the device under test 50 to rotate to the ON position, so that the device under test 50 is turned on; by controlling the sliding table 74 to move, the operating lever 75 drives the device under test 50 The start switch of the device is rotated to the off position, so that the device under test 50 is turned off, so that the device under test can be controlled quickly, accurately and cyclically, and the efficiency and safety of the experiment are improved. The speed and frequency of the operation depend on the frequency of the pulses sent by the main control device 40, and the speed can be adjusted at will, and can be specifically set according to the actual situation.

In practical applications, the motion control unit 71 can be a motion controller with a model of HC130-3, the motor drive unit 72 can be a motor driver with a model of HC-6560-V4, and the motor 73 can be a stepper motor with a model of 57HC2P76. The shaft diameter is 8mm, the slide table 74 can be a CNC three-axis slide table, such as a three-dimensional XYZ synchronous belt side-up structure slide table, the operating rod 75 can be a manipulator, and a three-dimensional manipulator can be formed through these parts, and the device 50 to be tested can be started and controlled. . Among them, the stepping motor can be arranged at one end of the CNC three-axis slide table, as shown in Figure 8, to control the movement of the corresponding axial slide table in the CNC three-axis slide table on the track.

During testing, the signal acquisition device 20 can be connected to the output end of the voltage sag generator 10 first, and the signal acquisition device 20 can be electrically connected to the main control device 40 through a data cable for data communication, and at the same time the state The probe of the device 30 is aligned with the working indicator light of the device under test 50, and the state acquisition device 30 is electrically connected to the main control device 40 through a data cable for data communication. Then, the standard voltage experiment is started. At this time, the first switch S1 and the second switch S2 are controlled to keep the disconnected state, and the third switch S3 is controlled to be closed. Start the control signal to the start control device 70 (such as a three-dimensional manipulator) to start the device under test 50. At this time, it can be detected whether the device under test 50 can work normally under the normal power supply state, if not, replace the device under test 50; if If possible, the main control device 40 records the output voltage and output current of the alternating current power supply AC and the working state of the device under test 50 as a reference value when the voltage sags.

Then, the voltage sag experiment is started, at this time, the third switch S3 is controlled to be turned off, and the first switch S1 and the second switch S2 are controlled to be turned on. The drop generating device 10 is powered on and works, and outputs a stable alternating current to the device under test 50 . At this time, the main control device 40 can output a start control signal to the start control device 70 to start the equipment under test 50. Then, the main control device 40 sends a voltage sag signal to the voltage sag generation device 10, and the voltage sag generation device 10 according to The voltage sag signal outputs the corresponding voltage sag, and the main control device 40 records the output voltage and output current of the voltage sag generator 10 and the working state of the device under test 50, and compares them with the reference value obtained during the standard voltage experiment analysis to obtain the voltage sag sensitivity of the device under test 50 .

The above-mentioned voltage sag experimental platform can generate a single voltage sag or continuous voltage sag of any initial phase, any sag depth, and any sag duration through the voltage sag generating device to the equipment to be tested, and pass the signal acquisition device. Collect the voltage waveform and current waveform of voltage sag, and automatically operate the device under test by starting the control device, identify the working state of the device under test through the state acquisition device, and realize the organic integration and coordinated control of each device through the main control device , so as to realize the automatic cycle experiment of voltage sag, automatic operation, automatic recording and analysis of data. Moreover, in the test process, the user can basically complete the voltage sag test by operating the main control device, which improves the convenience of the test, effectively reduces the labor cost and material cost, and improves the safety of the user and equipment during the test process. And the whole experimental platform has the characteristics of low cost and high operation efficiency, which is of great significance for the voltage sag test of various types of voltage-sensitive devices under test such as frequency converters.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present utility model, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the utility model patent. It should be pointed out that for those of ordinary skill in the art, some modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for this utility model shall be subject to the appended claims.

Claims (10)

1. A voltage sag experiment platform, comprising:

the output end of the voltage sag generating device is electrically connected with the equipment to be tested and used for outputting corresponding voltage sag to the equipment to be tested according to the voltage sag signal;

the signal acquisition device is arranged at the output end of the voltage sag generation device and is used for acquiring the output voltage and the output current of the voltage sag generation device;

the state acquisition device is arranged corresponding to the equipment to be tested and is used for acquiring the working state of the equipment to be tested;

the master control device is electrically connected with the voltage sag generating device, the signal collecting device and the state collecting device respectively, is used for outputting the voltage sag signal to the voltage sag generating device, and analyzes the voltage sag sensitivity of the equipment to be tested according to the output voltage and the output current of the voltage sag generating device and the working state of the equipment to be tested.

2. The platform of claim 1, wherein the device under test is a frequency converter under test.

3. The platform of claim 1, wherein the voltage sag generating device comprises:

the direct current capacitor is electrically connected between the output ends of the direct current power supply;

the input end of the inverter circuit is electrically connected with the direct current capacitor, and the control end of the inverter circuit is electrically connected with the main control device and used for converting direct current output by the direct current power supply into voltage sag according to the voltage sag signal;

and the input end of the filter circuit is electrically connected with the output end of the inverter circuit, and the output end of the filter circuit is electrically connected with the equipment to be tested, so that the filter circuit is used for filtering the voltage sag and transmitting the filtered voltage sag to the equipment to be tested.

4. The platform of claim 1, wherein the signal acquisition device comprises a voltage signal acquisition unit and a current signal acquisition unit, wherein the voltage signal acquisition unit comprises: the voltage acquisition and conditioning circuit is used for acquiring the output voltage of the voltage sag generator and outputting a first analog signal, and the voltage data acquisition circuit is used for converting the first analog signal into a first digital signal and outputting the first digital signal to the main control device;

the current signal acquisition unit includes: the voltage sag generator comprises a current acquisition and conditioning circuit and a current data acquisition circuit, wherein the current acquisition and conditioning circuit is used for acquiring output current of the voltage sag generator and outputting a second analog signal, and the current data acquisition circuit is used for converting the second analog signal into a second digital signal and outputting the second digital signal to the main control device.

5. The platform of claim 4, wherein the voltage acquisition conditioning circuit comprises:

the voltage transformer is arranged at the output end of the voltage sag generating device and used for collecting the output voltage of the voltage sag generating device and outputting the first analog signal;

the first isolation circuit is electrically connected with the voltage transformer and used for following the first analog signal and isolating the first analog signal;

the first voltage stabilizing circuit is electrically connected with the first isolating circuit and used for stabilizing the first analog signal within a first preset analog signal range.

6. The platform of claim 4, wherein the current collection conditioning circuit comprises:

the current transformer is arranged at the output end of the voltage sag generating device and used for collecting the output current of the voltage sag generating device and outputting the second analog signal;

the second isolation circuit is electrically connected with the current transformer and used for following the second analog signal and isolating the second analog signal;

and the second voltage stabilizing circuit is electrically connected with the second isolating circuit and is used for stabilizing the second analog signal within a second preset analog signal range.

7. The platform of claim 3, wherein the DC power supply comprises: and the rectifying circuit is electrically connected with the alternating current power supply and the voltage sag generating device respectively and is used for converting alternating current output by the alternating current power supply into direct current.

8. The platform of claim 7, further comprising:

a first switch, disposed between the dc power supply and the voltage sag generator, for controlling the on/off of the dc power supply and the voltage sag generator;

the second switch is arranged between the voltage sag generating device and the equipment to be tested and is used for controlling the connection and disconnection of the voltage sag generating device and the equipment to be tested;

and the third switch is arranged between the alternating current power supply and the equipment to be tested and used for controlling the connection and disconnection between the alternating current power supply and the equipment to be tested.

9. The platform of any one of claims 1-8, further comprising: and the signal input end of the starting control device is electrically connected with the main control device, and the mechanical output end of the starting control device corresponds to the starting switch of the equipment to be tested and is used for controlling the equipment to be tested to start according to the starting signal output by the main control device.

10. The platform of claim 9, wherein the activation control device comprises:

the motion control unit is electrically connected with the main control device and used for outputting a pulse signal according to a starting signal output by the main control device;

the motor driving unit is electrically connected with the motion control unit and used for outputting a driving signal according to the pulse signal;

the motor is electrically connected with the motor driving unit and is used for rotating according to the driving signal;

and the sliding table is mechanically connected with the motor and the operating rod respectively and is used for controlling the operation of the operating rod under the driving of the motor so as to control the starting of the equipment to be tested.

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