CN205898976U - A low-voltage test system for simulating motor load characteristics based on frequency converter - Google Patents

Abstract

The utility model provides a low voltage test system of simulation motor load characteristic based on converter, includes that alternating current power supply, voltage fall appearance, three -phase converter, measuring device, magnetic powder brake, programmable power supply and operation backstage. System setting voltage falls the appearance parameter, and simulation power grid falls the operating mode in the twinkling of an eye, through scene record wave number certificate, set for magnetic powder brake braking simulation curve, the rotational speed that control was awaited measuring between motor and the magnetic powder brake is poor. The utility model discloses a setting for voltage and falling the appearance parameter, simulation power grid falls the operating mode in the twinkling of an eye, through scene record wave number certificate, set for magnetic powder brake braking simulation curve, the rotational speed that control was awaited measuring between motor and the magnetic powder brake is poor, converter information real -time upload operates the backstage, through backstage computer match torque, rotational speed curve, and control programmable power supply output excitation current, simulation motor operating condition meritorious, reactive power down export, truly simulates the various operating modes of motor under the motor inertial element condition fully considering.

Description

A low-voltage test system for simulating motor load characteristics based on frequency converter

technical field

The utility model relates to a low-voltage test system for simulating motor load characteristics based on a frequency converter, which belongs to the technical field of motor testing.

Background technique

In contemporary society, with the rapid development of industrial production, the motor is used more and more widely as a traction power source. As an important tool for motor speed regulation, the frequency converter can adjust the speed of the motor steplessly in real time and accurately control the output power of the motor. When the transient, dynamic or long-term power input line voltage drops to the specified low-voltage ride-through area caused by external power supply faults or disturbances under the traction motor working condition, observe the operation of the inverter. At present, most conventional methods for testing low-voltage ride-through of inverters directly use inverters with resistive loads. Resistive loads are difficult to simulate various load characteristics, or inverters drive motors, and generators coaxially drive the brake system, which is difficult to accurately control. After running for a long time, it needs to be adjusted continuously due to friction. At the same time, the frequency converter changes the speed of the motor. It is difficult to simulate the load condition through the generator, or the current popular method of simulating the active and reactive power of the motor under various working conditions through power electronic loads. curve, but the obvious disadvantage of this power electronic load is that it is difficult to simulate the inertia link of the motor.

Another existing method is to perform parameter debugging by using a magnetic powder brake to simulate a load test bench. The load simulation test bench is composed of a motor, a frequency converter, a sensor, a magnetic powder brake, a program-controlled power supply, and an operating table. The console is connected to the sensor to receive the sensing signal from the sensor. The console is connected to the magnetic powder brake to control the brake through the program-controlled power supply. The console and the voltage drop device are used to output control commands to control the voltage drop device. In this test bench, the operator adjusts the output braking torque by controlling the brake, thus simulating loads with different torques. The voltage drop tester is only used to adjust the voltage amplitude, time, frequency, etc. of the input AC power.

Contents of the invention

The purpose of the utility model is to solve the problems existing in the conventional method of testing the low-voltage ride-through of the frequency converter to control the operation of the motor. The utility model proposes a low-voltage test system for simulating the load characteristics of the motor based on the frequency converter.

The technical solution for realizing the utility model is a low-voltage test system for simulating motor load characteristics based on a frequency converter, including a 380V AC power supply, a voltage drop meter, a three-phase frequency converter, a measuring device, a magnetic powder brake, a program-controlled power supply and an operating background.

The 380V AC power supply is connected to the input terminal of the voltage drop instrument; the output terminal of the voltage drop instrument is connected to the three-phase frequency converter; the output of the three-phase frequency converter drives the tested motor to rotate; the measuring device collects and measures the rotational speed of the tested motor through the sensing element , torque and other parameters; the magnetic powder brake is used as a simulated load to simulate the inertial link of the motor, and the torque of the motor under test is changed by adjusting the excitation 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 will collect the The speed, torque and temperature fault information are sent to the operation background for processing; the operation background controls the voltage amplitude, frequency and drop time settings of the voltage drop instrument.

The system sets the parameters of the voltage drop meter to simulate the instantaneous drop condition of the power grid; through the on-site wave recording data, the braking simulation curve of the magnetic powder brake is set to control the speed difference between the motor to be tested and the magnetic powder brake; the frequency converter information is uploaded in real time Operation background.

Set the parameters of the voltage drop instrument, including voltage drop amplitude (20%, 60%, 90%, 130% of rated voltage), drop time, frequency plus or minus 2%, which can be set cyclically through the background software.

The program-controlled power supply is a DC source controlled by the operating background, and the DC source is a power electronic device, and the magnitude of the current is controlled by the operating background outputting instructions.

Formulate the braking simulation curve of the magnetic powder brake. According to the different industrial sites of the test inverter, it is necessary to collect the data of the inverter on the site when the motor starts, suddenly increases active power, suddenly decreases active power, short-term overload, voltage drop amplitude time and stops. The curves of torque, speed and current are fitted by operating the background computer to fit the torque and speed curves, control the program-controlled power supply to output the excitation current, and simulate the active and reactive power output under the operating conditions of the motor, fully considering the inertial link of the motor , to truly simulate various working conditions of the motor.

Close the input switch of the frequency converter, start the voltage drop tester, the frequency converter drives the motor to rotate, the operation background controls the program-controlled power supply through the analog curve, outputs the excitation current, and the measuring unit actually tests whether the speed, torque and the background curve can coincide, and the formula T _ref -T _measurement <△T, the actual value and the fitting value coincide, the control is accurate, T _ref -T _measurement >△T, if it does not coincide, it is necessary to increase the PI link, reduce the error, check the program-controlled power supply current, and complete it through the background operation Closed loop test.

Verify that when the inverter has power quality problems, there will be information such as undervoltage, overvoltage lockout, and fault restart, test the alarm when the inverter has multiple power quality conditions, and verify that the inverter has low voltage ride-through capability or has low voltage after transformation. For the test of the voltage ride-through frequency converter, after the frequency converter fault alarms, the information is uploaded to the operation background, the operation background stops the voltage drop instrument, and the test stops.

The beneficial effect of the utility model is that the utility model is based on the frequency converter-based low-voltage test system for simulating the load characteristics of the motor, by setting the parameters of the voltage drop instrument, simulating the instantaneous drop condition of the power grid; Simulate the curve to control the speed difference between the motor to be tested and the magnetic powder brake; the inverter information is uploaded to the operation background in real time; through the operation background computer to fit the torque and speed curve, control the program-controlled power supply to output the excitation current, and simulate the motor under operating conditions Active and reactive power output, with full consideration of the motor inertia link, can truly simulate various working conditions of the motor.

Description of drawings

Figure 1 is a schematic diagram of a low-voltage test system for simulating motor load characteristics based on a frequency converter;

Fig. 2 is a low-voltage test flow chart of a simulated motor load characteristic based on a frequency converter.

detailed description

The specific embodiment of the utility model is as shown in Figure 1.

This implementation is a low-voltage test system for simulating motor load characteristics based on frequency converters, including motors, frequency converters, sensors, magnetic powder brakes, program-controlled power supplies, and consoles. The output is connected to the input of the frequency converter, the output of the frequency converter drives the motor to rotate, the speed of the motor is changed by changing the output frequency of the frequency converter, and the parameters such as speed and torque are tested in the measurement link. Increase or decrease change torque.

First of all, according to the different occasions of testing the frequency converter, it is necessary to collect the frequency converter on site, the curves of motor starting, sudden increase in active power, sudden decrease in active power, short-term overload, voltage drop amplitude time and stop, motor torque, speed, and current. By operating the background computer to fit the torque and speed curves, control the program-controlled power supply to output the excitation current, simulate the active and reactive power output under the operating conditions of the motor, and truly simulate various working conditions of the motor. The specific embodiment of the utility model is shown in Figure 2

The operation background controls the program-controlled power supply through the analog curve, outputs the excitation current, and the measurement unit actually tests whether the speed, torque and the background curve can coincide. The formula T _ref -T is used to _measure <△T. If the actual value coincides with the fitting value, the control is accurate. T _ref -T _measurement >△T, if there is no coincidence, it is necessary to increase the PI link to reduce the error and check the program-controlled power supply current, so as to complete the closed-loop check test through the operation background.

After the calibration is completed, the parameters of the voltage drop instrument are set in the background of the operation, including the voltage drop amplitude (20%, 60%, 90%, 130% of the rated voltage), drop time, and frequency deviation of 2%. The voltage drop value and time can be cycled through multiple points set up. The inverter will have fault information such as undervoltage, overvoltage lockout, and fault restart. After the inverter fault alarms, the information will be uploaded to the operation background, and the operation background will stop the voltage drop instrument, record the voltage fluctuation curve and the fault information of the inverter, and at the same time The test stops, otherwise the test continues until the functionality of the frequency converter under low voltage conditions is fully tested.

This embodiment can also verify the test of the inverter without low-voltage ride-through capability after being modified.

Claims (5)

1. a kind of simulated machine load characteristic low voltage test system based on converter, falls including 380v alternating current power supply, voltage Fall instrument, three phase converter, measurement apparatus, magnetic powder brake, programmable power supply and operation backstage,

It is characterized in that, described 380v alternating current power supply connects the input of Voltage Drop instrument；The outfan of Voltage Drop instrument connects Three phase converter；Three phase converter output drives tested motor rotation；Measurement apparatus are gathered by sensing element and measure quilt The parameters such as the rotating speed of examination motor, torque；Magnetic powder brake as simulation motor inertia link fictitious load, by adjust Exciting curent increaseds or decreases the tested motor torque of change；Programmable power supply is subject to operation Background control to provide electricity for magnetic powder brake Source；The rotating speed collecting, torque and temperature fault information are delivered to operation background process by measurement apparatus；Operation Background control voltage Fall voltage magnitude, frequency and the drop-out time setting of instrument；

Described default Voltage Drop instrument parameter, simulating grid moment falls operating mode；By recorded field data, set magnetic powder Brake simulation curve, controls the speed discrepancy treating between measured motor and magnetic powder brake；Converter information uploads behaviour in real time Make backstage.

2. a kind of simulated machine load characteristic low voltage test system based on converter according to claim 1, its feature It is, described Voltage Drop instrument parameter includes the rated voltage of Voltage Drop amplitude 20%, 60%, 90%, 130%, drop-out time, frequently Rate positive and negative 2%, described Voltage Drop instrument parameter can be circularly set by daemon software.

3. a kind of simulated machine load characteristic low voltage test system based on converter according to claim 1, its feature It is, described programmable power supply is the DC source by operation Background control, this DC source is power electronic equipment, by operating backstage Output order control electric current size.

4. a kind of simulated machine load characteristic low voltage test system based on converter according to claim 1, its feature It is, simulation curve braked by described magnetic powder brake, different according to test frequency converter's industry spot, need to collect live the type Converter electric motor starting, uprush that active, anticlimax is active, short-time overload, Voltage Drop amplitude time different situations and stopping, electricity Machine torque, rotating speed, the curve of electric current, by backstage computer matching torque, speed curves, control programmable power supply to export excitatory electricity Stream, active, the reactive power output under simulated machine operating condition, in the case of taking into full account motor inertial element, true mould Intend the various operating modes of motor；

Described system is closed converter input switch, starts Voltage Drop instrument, and converter drive motor rotates, and operation backstage is passed through Simulation curve controls programmable power supply, exports exciting curent, can measuring unit actual test rotating speed, torque and backstage curve weigh Close, by formula t_ref-t_Survey< △ t, actual value is overlapped with match value then precise control, t_ref-t_Survey> △ t, misaligned, need to increase Pi link, reduces error, checks programmable power supply electric current, completes closed loop test with this by consistency operation.

5. a kind of simulated machine load characteristic low voltage test system based on converter according to claim 1, its feature It is, described system checking is when converter is in generation power quality problem it may appear that letter is restarted in under-voltage, over-pressed locking, fault Breath, the warning in the case of the many quality of power supply of test frequency converter, checking simultaneously possesses low voltage ride-through capability converter or transformation Possess the test of low voltage ride-through capability converter afterwards, after frequency converter failure is reported to the police, information upload operation backstage, operate backstage Stop the work of Voltage Drop instrument, test stops.