CN106093776B - Frequency converter-based low-voltage test system for load characteristics of analog motor - Google Patents

Frequency converter-based low-voltage test system for load characteristics of analog motor Download PDF

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CN106093776B
CN106093776B CN201610587361.XA CN201610587361A CN106093776B CN 106093776 B CN106093776 B CN 106093776B CN 201610587361 A CN201610587361 A CN 201610587361A CN 106093776 B CN106093776 B CN 106093776B
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frequency converter
motor
voltage
power supply
magnetic powder
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CN106093776A (en
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荣彩霞
徐在德
王凯
范瑞祥
吴利平
张建忠
许庆辉
邹进
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State Grid Corp of China SGCC
Electric Power Research Institute of State Grid Jiangxi Electric Power Co Ltd
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State Grid Corp of China SGCC
Electric Power Research Institute of State Grid Jiangxi Electric Power Co Ltd
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/34Testing dynamo-electric machines

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Abstract

A low-voltage test system for the load characteristics of an analog motor based on a frequency converter comprises an alternating current power supply, a voltage sag instrument, a three-phase frequency converter, a measuring device, a magnetic powder brake, a programmable power supply and an operation background. The system sets parameters of a voltage sag instrument and simulates the instantaneous sag working condition of a power grid; and setting a magnetic powder brake braking simulation curve through the on-site recording data, and controlling the rotation speed difference between the motor to be tested and the magnetic powder brake. According to the invention, the instantaneous drop-out working condition of the power grid is simulated by setting the parameters of the voltage drop-out instrument; setting a magnetic powder brake braking simulation curve through on-site recording data, and controlling the rotation speed difference between the motor to be tested and the magnetic powder brake; the information of the frequency converter is uploaded to an operation background in real time, a torque and rotating speed curve is fitted through a background computer, the programmable power supply is controlled to output exciting current, the active power output and the reactive power output under the operation working condition of the motor are simulated, and various working conditions of the motor are simulated truly under the condition of fully considering the inertia link of the motor.

Description

Frequency converter-based low-voltage test system for load characteristics of analog motor
Technical Field
The invention relates to a frequency converter-based low-voltage test system for simulating motor load characteristics, and belongs to the technical field of motor testing.
Background
In the modern society, the rapid development of industrial production, the motor is used as a traction power source and is increasingly widely used, the frequency converter is used as an important tool for motor speed regulation, the frequency converter can be used for stepless regulation of the motor speed in real time, the output power of the motor is accurately controlled, and when the transient state, dynamic state or long-time power supply incoming line voltage caused by external power supply faults or disturbance under the working condition of the frequency converter traction motor is reduced to a specified low-voltage passing area, the action condition of the frequency converter is observed. The conventional method for testing the low voltage ride through of the frequency converter at present is mostly and directly characterized in that the frequency converter is provided with a resistive load, the resistive load is difficult to simulate various load characteristics or the frequency converter drives a motor, a generator coaxially drives a brake system, the brake system is difficult to accurately control, the brake system is continuously adjusted after long-time running due to friction, meanwhile, the frequency converter changes the rotating speed of the motor, the load working condition is difficult to simulate through the generator, or the active and reactive curves of the motor under various working conditions are difficult to simulate through the power electronic load, but the power electronic load has the obvious defect of being difficult to simulate the inertia link of the motor.
Another existing method is to perform parameter tuning by using a magnetic powder brake to simulate a load test stand. The load simulation test board is composed of a motor, a frequency converter, a sensor, a magnetic powder brake, a programmable power supply, an operation board and the like. The operation panel is connected with the sensor and is used for receiving the sensing signal of the sensor, the operation panel is connected with the magnetic powder brake and controls the brake to work through the programmable power supply, and the operation panel is used for outputting a control command to control the voltage dropping device. In the test board, the operation board adjusts the magnitude of the output braking moment by controlling the brake, so that loads with different moments are simulated, and the voltage drop instrument is only used for adjusting the voltage amplitude, time, frequency and the like of the input alternating current power supply.
Disclosure of Invention
The invention aims to solve the problem of motor operation control by the conventional method for testing the low voltage ride through of a frequency converter, and provides a frequency converter-based system for testing the load characteristic low voltage of an analog motor.
The technical scheme of the invention is that the low-voltage test system for the load characteristic of the analog motor based on the frequency converter comprises a 380V alternating current power supply, a voltage drop instrument, a three-phase frequency converter, a measuring device, a magnetic powder brake, a programmable power supply and an operation background.
The 380V alternating current power supply is connected with the input end of the voltage sag instrument; the output end of the voltage drop instrument is connected with a three-phase frequency converter; the output of the three-phase frequency converter drives the tested motor to rotate; the measuring device collects and measures parameters such as the rotating speed, the torque and the like of the tested motor through the sensing element; the magnetic powder brake is used as a simulation load for simulating an inertia link of the motor, and the torque of the tested motor is changed by adjusting the exciting current to increase or decrease; the program-controlled power supply is controlled by the operation background to provide power for the magnetic powder brake; the measuring device sends the collected rotating speed, torque and temperature fault information to an operation background for processing; and controlling voltage amplitude, frequency and drop time settings of the voltage drop instrument by operating the background.
The system sets parameters of a voltage sag instrument and simulates the instantaneous sag working condition of a power grid; setting a magnetic powder brake braking simulation curve through on-site recording data, and controlling the rotation speed difference between the motor to be tested and the magnetic powder brake; and uploading the information of the frequency converter to an operation background in real time.
The parameters of the voltage drop instrument are set to include voltage drop amplitude (20%, 60%, 90%, 130% rated voltage), drop time and frequency plus or minus 2%, and can be set circularly through background software.
The programmable power supply is a direct current source controlled by the operation background, the direct current source is a power electronic device, and the magnitude of current is controlled by the output instruction of the operation background.
And (3) making a magnetic powder brake braking simulation curve, according to different industrial sites of the test frequency converter, collecting curves of the type of frequency converter on the site under the conditions of different motor starting, sudden increase active, sudden decrease active, short-time overload and voltage drop amplitude time and stopping, and controlling a programmable power supply to output exciting current by fitting the curves of the torque, the rotating speed through an operation background computer so as to simulate the active and reactive power output under the operation working condition of the motor, wherein various working conditions of the motor are truly simulated under the condition of fully considering the inertia link of the motor.
And (3) switching on an input switch of a frequency converter, starting a voltage drop instrument, driving a motor to rotate by the frequency converter, controlling a programmable power supply through an analog curve by an operation background, outputting exciting current, measuring whether the actual test rotating speed and torque of a unit can be overlapped with a background curve or not, and determining whether the actual test rotating speed and torque can be overlapped with the background curve according to a formula T ref -T Measuring <Delta T, accurate control when the actual value coincides with the fitting value, T ref -T Measuring >If delta T is not overlapped, PI links are added, errors are reduced, and the current of the programmable power supply is checked, so that closed loop testing is completed through background operation.
When the frequency converter has the power quality problem, information such as undervoltage, overvoltage locking, fault restarting and the like can appear, the frequency converter is tested for alarming under the condition of multiple power quality, meanwhile, the frequency converter with low voltage ride through capability is verified or the frequency converter with low voltage ride through capability is tested after being transformed, after the frequency converter is in fault alarming, the information is uploaded to an operation background, the operation background stops the work of the voltage drop instrument, and the test is stopped.
The invention has the beneficial effects that the low-voltage test system based on the load characteristic of the frequency converter for the simulated motor simulates the instantaneous drop working condition of the power grid by setting the parameters of the voltage drop instrument; setting a magnetic powder brake braking simulation curve through on-site recording data, and controlling the rotation speed difference between the motor to be tested and the magnetic powder brake; uploading information of the frequency converter to an operation background in real time; the torque and rotating speed curves are fitted through operating a background computer, the programmable power supply is controlled to output exciting current, the active power and reactive power output under the operation working condition of the motor are simulated, and various working conditions of the motor are truly simulated under the condition that the inertia links of the motor are fully considered.
Drawings
FIG. 1 is a schematic diagram of a system for testing load characteristics of an analog motor based on a frequency converter;
fig. 2 is a flow chart of a low voltage test of the load characteristics of an analog motor based on a frequency converter.
Detailed Description
An embodiment of the present invention is shown in fig. 1.
The utility model provides a simulation motor load characteristic low voltage test system based on converter, including motor, the converter, the sensor, the magnetic powder stopper, programmable power supply and operation panel etc. after system one, secondary wiring and communication debugging, the voltage drop appearance output is connected with the converter input, the converter output drives the motor rotation, change the rotational speed of motor through changing the converter output frequency, parameters such as measurement link test rotational speed, moment of torsion, the magnetic powder stopper is as the simulation load of simulation motor inertia link, increase or reduce the change moment of torsion through adjusting exciting current.
According to different occasions of a test frequency converter, the frequency converter is required to be collected on site, the motor is started, active power is suddenly increased, active power is suddenly reduced, short-time overload is carried out, voltage drop amplitude values are different in time, the motor is stopped, curves of torque, rotating speed and current are fitted through operating a background computer, exciting current is controlled to be output by a programmable power supply, active power and reactive power output under the operation working condition of the motor are simulated, and various working conditions of the motor are truly simulated. Detailed description of the invention As shown in FIG. 2
The operation background controls the programmable power supply through the simulation curve, outputs exciting current, and the measuring unit actually tests whether the rotating speed and the torque can be overlapped with the background curve or not, and the exciting current is calculated according to the formula T ref -T Measuring <Delta T, accurate control when the actual value coincides with the fitting value, T ref -T Measuring >If delta T is not overlapped, PI links are added, errors are reduced, and the current of the programmable power supply is checked, so that closed loop check test is completed through an operation background.
After the checking is finished, setting voltage sag parameters including voltage sag amplitude (20%, 60%, 90%, 130% rated voltage), sag time and frequency deviation 2% by operating a background, wherein the voltage sag value and the voltage sag time can be set circularly and in multiple points. The frequency converter can have fault information such as under-voltage, overvoltage locking, fault restarting and the like, after the frequency converter alarms due to faults, the information is uploaded to an operation background, the operation background stops the work of the voltage drop instrument, the fluctuation curve of voltage and the fault information of the frequency converter are recorded, meanwhile, the test is stopped, and otherwise, the test is continued until the function of the frequency converter under the condition of low voltage is completely tested.
The embodiment can also verify that the frequency converter without the low voltage ride through capability is subjected to the test of the frequency converter with the low voltage ride through capability after being transformed.

Claims (4)

1. A low-voltage test system for simulating motor load characteristics based on a frequency converter comprises a 380V alternating current power supply, a voltage drop instrument, a three-phase frequency converter, a measuring device, a magnetic powder brake, a programmable power supply and an operation background,
the 380V alternating current power supply is connected with the input end of the voltage drop instrument; the output end of the voltage drop instrument is connected with a three-phase frequency converter, and the three-phase frequency converter outputs to drive the tested motor to rotate; the measuring device collects and measures the rotation speed and torque parameters of the tested motor through the sensing element; the magnetic powder brake is used as a simulation load for simulating an inertia link of the motor; changing the torque of the tested motor by adjusting the exciting current to increase or decrease; the program-controlled power supply is controlled by the operation background to provide power for the magnetic powder brake; the measuring device sends the collected rotating speed, torque and temperature fault information to an operation background for processing; operating a background to control voltage amplitude, frequency and drop time settings of the voltage drop instrument;
the system sets parameters of a voltage sag instrument and simulates the instantaneous sag working condition of a power grid; setting a magnetic powder brake braking simulation curve through on-site recording data, and controlling the rotation speed difference between the motor to be tested and the magnetic powder brake; uploading information of the frequency converter to an operation background in real time; according to different industrial sites of the test frequency converter, the data of motor torque, rotating speed and current are required to be collected when the field frequency converter is started, the active power is suddenly increased, the active power is suddenly reduced, the short-time overload, the voltage drop amplitude and the drop time are different and the motor is stopped, the exciting current is controlled to be output by a programmable power supply through fitting a torque and rotating speed curve by an operation background, the active power output and the reactive power output under the operation working condition of the motor are simulated, and under the condition of fully considering the inertia link of the motor, various working conditions of the motor are truly simulated; the system is characterized in that an input switch of a frequency converter is closed, a voltage drop instrument is started, the frequency converter drives a motor to rotate, an operation background controls a programmable power supply through a simulation curve, exciting current is output, a measuring device measures whether an actual test torque can be overlapped with an operation background fitting torque curve, if the actual value is overlapped with the fitting value within a certain deviation range, the control is accurate, if the actual value is not overlapped within the certain deviation range, PI links are needed to be added, errors are reduced, the current of the programmable power supply is checked, and therefore closed loop test is completed through the operation background; after the checking is finished, setting parameters of the voltage sag instrument by operating a background, and circularly and multipoint setting the parameters of the voltage sag instrument; the method comprises the steps that under-voltage, over-voltage locking and fault restarting fault information can appear on a frequency converter, after the frequency converter alarms due to faults, the frequency converter information is uploaded to an operation background, the operation background stops the work of a voltage drop instrument, a fluctuation curve of voltage and the fault information of the frequency converter are recorded, meanwhile, testing is stopped, and otherwise, testing is continued until the functions of the frequency converter under the condition of low voltage are completely tested.
2. The system for testing the load characteristics of the analog motor based on the frequency converter according to claim 1, wherein the voltage sag meter parameters comprise rated voltage of 20%, 60%, 90% and 130% of voltage sag amplitude, sag time and frequency plus or minus 2%, and the voltage sag meter parameters are circularly set through background software.
3. The system for testing the load characteristics of the analog motor with the low voltage based on the frequency converter according to claim 1, wherein the programmable power supply is a direct current source controlled by an operation background, the direct current source is a power electronic device, and the magnitude of the current is controlled by outputting instructions through the operation background.
4. The system for testing the load characteristics of the simulated motor based on the frequency converter according to claim 1, wherein the system verifies that under-voltage, over-voltage locking and fault restarting information can occur when the frequency converter has the power quality problem, alarms under the condition of testing the frequency converter with multiple power quality are tested, meanwhile, the frequency converter with low voltage ride-through capability or the frequency converter with low voltage ride-through capability after transformation is verified, after the frequency converter fails to alarm, an information uploading operation background stops the operation of the voltage sag meter, and the testing is stopped.
CN201610587361.XA 2016-07-25 2016-07-25 Frequency converter-based low-voltage test system for load characteristics of analog motor Active CN106093776B (en)

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CN106908724A (en) * 2017-03-02 2017-06-30 国家电网公司 A kind of large-scale phase modifier scene no-load characteristic measurement method
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CN110474362B (en) * 2019-07-11 2023-08-25 广东明阳龙源电力电子有限公司 Low-voltage ride through control method and system for high-voltage high-capacity frequency converter
CN111781550A (en) * 2020-06-18 2020-10-16 国联汽车动力电池研究院有限责任公司 Electrical performance testing system
CN112698198A (en) * 2020-12-03 2021-04-23 浙江大学台州研究院 STM 32-based motor durability test system

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