A frequency converter test system and test method thereof

Abstract

The invention discloses a frequency converter test system and a test method thereof. In the frequency converter test system, an asynchronous motor drive system frequency converter is powered and controlled by a control cabinet, the control cabinet is powered by a power grid 380V and connected to its input end, the power input end of the asynchronous motor drive frequency converter is connected to the control cabinet through a test fixture, the P and N output ends of the system asynchronous motor drive frequency converter are connected to the P and N input ends of an inverter unit, the output end of the inverter unit is connected to the input end of a sine filter, the output end of the sine filter is connected to the input end of the tested asynchronous motor drive frequency converter, the output end of the asynchronous motor drive system frequency converter is connected to a three-phase asynchronous motor II, and the output end of the asynchronous motor drive frequency converter is connected to a three-phase asynchronous motor I. The invention changes the installation mode of the motor in the traditional system, connects the motor with a steering gear, changes the direction of the motor, enables four motors to run simultaneously, reduces the installation space, increases the variability of the load, and increases the load range.

Description

Technical Field

[0001] The present invention relates to the technical field of motor performance testing, and in particular to a frequency converter testing system and a testing method thereof. Background Art

[0002] A variable-frequency drive (VFD) is a power control device that controls an AC motor by changing the frequency of the motor's power supply. The performance changes of the VFD have a great impact on the AC motor, so it is very important to test the performance of the VFD. Currently, the VFD test uses a fixed load, which has certain limitations. The large gap between the fixed load and the variable load in the actual application scenario makes the test results of the VFD not very accurate.

[0003] To this end, a frequency converter test system and frequency converter test method are disclosed in the patent specification with publication number CN111413568A. The frequency converter test system includes: a drive motor and a load motor, the drive motor and the load motor are connected in a motor-to-motor manner; the drive motor is used to connect to a first frequency converter, the first frequency converter is used as a test frequency converter; the second frequency converter is used as a load frequency converter to connect to the load motor; a processing module is connected to the second frequency converter, used to obtain environmental information, and adjust the working state provided by the second frequency converter to the load motor based on the environmental information, and is also used to connect to the first frequency converter to obtain the working parameters of the first frequency converter. The load motor in the tow motor is used to simulate the load in the actual application scenario, so that the test of the frequency converter simulates the actual application scenario, and the obtained result is more accurate.

[0004] However, the above inverter test system and inverter test method have shortcomings. First, the motor installation method is not scientific and reasonable, and the installation space requirement is high, which limits the load variability and load range; second, the current has a great impact on the external power grid, and is not energy-saving and environmentally friendly. Therefore, it needs to be optimized and improved. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art and to provide a frequency converter test system and a test method thereof, which change the installation method of the motor in the traditional system, connect the motor with a steering gear, and change the direction of the motor so that four motors can run at the same time, thereby reducing the installation space, increasing the variability of the load, and increasing the load range; through the frequency converter and inverter unit of the asynchronous motor drive system, the mechanical energy of the motor can be converted into electrical energy and transmitted to the asynchronous motor drive frequency converter for reuse to realize internal circulation, thereby reducing the impact of the current on the external power grid and achieving the purpose of energy saving and environmental protection.

[0006] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0007] A frequency converter test system, comprising a control cabinet, an asynchronous motor drive system frequency converter, an inverter unit, a sine wave filter, a three-phase asynchronous motor I, a three-phase asynchronous motor II, a motor torque sensor, an asynchronous motor drive frequency converter, a steering gear, a coupling and a test platform; the asynchronous motor drive system frequency converter is powered and controlled by the control cabinet, the control cabinet is powered by a power grid 380V connected to its input end, the power input end of the asynchronous motor drive frequency converter is connected to the control cabinet through a test fixture, the P and N output ends of the system asynchronous motor drive frequency converter are connected to the P and N input ends of the inverter unit, the output end of the inverter unit is connected to the input end of the sine filter, the output end of the sine filter is connected to the input end of the asynchronous motor drive frequency converter to be tested, the output end of the asynchronous motor drive system frequency converter is connected to the three-phase asynchronous motor II, and the output end of the asynchronous motor drive frequency converter is connected to the three-phase asynchronous motor I;

[0008] Two steering gears, three three-phase asynchronous motors I and one three-phase asynchronous motor II are installed on the test platform, one of the steering gears comprises an input shaft and two mutually perpendicular output shafts, and the input shaft is connected to the output shaft of the three-phase asynchronous motor II through a coupling and a motor torque sensor, one of the output shafts is connected to the output shaft of one three-phase asynchronous motor I through a coupling, and the other output shaft is connected to the output shaft of another steering gear through a coupling, and the other steering gear also comprises two mutually flush output shafts, and the output shafts are respectively connected to the output shafts of the other two three-phase asynchronous motors I through couplings.

[0009] Furthermore, in the above-mentioned frequency converter test system, contactors are installed on the power supply circuit of the frequency converter of the asynchronous motor drive system and the circuit between the asynchronous motor drive frequency converter and the three-phase asynchronous motor I and the sine filter.

[0010] Furthermore, in the above-mentioned inverter testing system, a fuse is installed in the line between the P output terminal of the system asynchronous motor driving inverter and the P input terminal of the inverter unit; a DC bus is installed in the line between the N output terminal of the system asynchronous motor driving inverter and the N input terminal of the inverter unit.

[0011] Furthermore, in the above-mentioned inverter testing system, a current sensor and a voltage sensor are installed in the line between the output end of the inverter unit and the input end of the sine filter.

[0012] Furthermore, in the above-mentioned inverter testing system, a T-slot is provided on the testing platform, and a movable seat for supporting the three-phase asynchronous motor I, the three-phase asynchronous motor II or the steering gear is slidably installed in the T-slot.

[0013] Furthermore, in the above-mentioned inverter testing system, a plurality of adjustment gaskets for adjusting the height are provided on the upper side of the movable seat. By adjusting the number of the adjustment gaskets, the horizontal height positions of the shafts of each motor can be made flush, and the central axes of the output shafts of the two relative motors can coincide with each other.

[0014] Furthermore, in the above-mentioned frequency converter testing system, the inner ends of the input shaft and the output shaft in the steering gear are transmission connected through an umbrella-shaped steering gear set.

[0015] Furthermore, in the above-mentioned inverter testing system, the testing method of the inverter testing system comprises the following steps:

[0016] S1. Press the start button, the contactor closes, the inverter of the asynchronous motor drive system is powered, and transmits the DC current to the power inverter unit through the PN line. The inverter unit inverts the current and outputs the three-phase AC current to the sine wave filter for filtering and shaping, and transmits the filtered current to the asynchronous motor drive inverter;

[0017] S2, running the asynchronous motor drive inverter, the motor drive inverter outputs current to the three-phase asynchronous motor I, and the three-phase asynchronous motor I is switched by disconnecting and closing the contactor. At this time, the current to the three-phase asynchronous motor I runs alone or simultaneously;

[0018] S3, the three-phase asynchronous motor I drives the three-phase asynchronous motor II to rotate, generating current. The three-phase asynchronous motor acts as a generator to transmit the three-phase current to the UVW end of the inverter of the asynchronous motor drive system. The inverter of the asynchronous motor drive system transmits the DC current to the power inverter unit through the PN line, forming an internal circulation of the current.

[0019] S4. Run the frequency converter of the asynchronous motor drive system. The UVW end of the frequency converter of the asynchronous motor drive system will change from receiving current to output current, driving the three-phase asynchronous motor II to run. At this time, the three-phase asynchronous motor II serves as a load to realize the test of the performance of the asynchronous motor drive frequency converter.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention changes the installation method of the motor in the traditional system, connects the motor with a steering gear, changes the direction of the motor, and allows four motors to run simultaneously, thereby reducing the installation space, increasing the variability of the load, and expanding the load range.

[0022] 2. In the system of the present invention, the P and N output terminals of the asynchronous motor drive inverter are connected to the input terminal of the inverter unit, the output terminal of the inverter unit is connected to the input terminal of the sine filter, the output terminal of the sine filter is connected to the input terminal of the asynchronous motor drive inverter under test, and then connected to the input terminal II of the three-phase asynchronous motor, so that the three-phase electricity can be internally circulated between the motor and the inverter without being connected to the power grid, thereby reducing interference to the power grid. At the same time, energy recycling can achieve the purpose of energy saving and environmental protection.

[0023] Of course, any product implementing the present invention does not necessarily need to achieve all of the above advantages at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0025] Figure 1 Schematic diagram of the circuit structure of the frequency converter test system in the present invention;

[0026] Figure 2 It is a structural schematic diagram of the test platform in the present invention;

[0027] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0028] 1-asynchronous motor drive system inverter, 2-contactor, 3-inverter unit, 4-fuse, 5-sine filter, 6-three-phase asynchronous motor I, 7-three-phase asynchronous motor II, 8-motor torque sensor, 9-asynchronous motor drive inverter, 10-current sensor, 11-voltage sensor, 12-adjusting gasket, 13-steering gear, 14-coupling, 15-test platform. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] See also Figure 1-2As shown, the present embodiment is a frequency converter test system, which includes a control cabinet, an asynchronous motor drive system frequency converter 1, an inverter unit 3, a sine wave filter 5, a three-phase asynchronous motor I6, a three-phase asynchronous motor II7, a motor torque sensor 8, an asynchronous motor drive frequency converter 9, a steering gear 13, a coupling 14 and a test platform 15; the asynchronous motor drive system frequency converter 1 is powered and controlled by the control cabinet, the control cabinet is connected to its input end by the power grid power supply 380V, the power input end of the asynchronous motor drive frequency converter 9 is connected to the control cabinet through a test fixture, the P and N output ends of the system asynchronous motor drive frequency converter 1 are connected to the P and N input ends of the inverter unit 3, the output end of the inverter unit 3 is connected to the input end of the sine filter 5, the output end of the sine filter 5 is connected to the input end of the asynchronous motor drive frequency converter 9 to be tested, the output end of the asynchronous motor drive system frequency converter 1 is connected to the three-phase asynchronous motor II7, and the output end of the asynchronous motor drive frequency converter 9 is connected to the three-phase asynchronous motor I6;

[0031] In this embodiment, two steering gears 13, three three-phase asynchronous motors I6 and one three-phase asynchronous motor II7 are installed on the test platform 15, wherein one steering gear 13 comprises an input shaft and two mutually perpendicular output shafts, and the input shaft is connected to the output shaft of the three-phase asynchronous motor II7 through a coupling 14 and a motor torque sensor 8, one of the output shafts is connected to the output shaft of one three-phase asynchronous motor I6 through a coupling 14, and the other output shaft is connected to the output shaft of another steering gear 13 through a coupling 14, and the other steering gear 13 also comprises two mutually flush output shafts, and the output shafts are respectively connected to the output shafts of the other two three-phase asynchronous motors I6 through couplings 14.

[0032] In this embodiment, a contactor 2 is installed on the power supply circuit of the asynchronous motor drive system inverter 1 and the circuit between the asynchronous motor drive inverter 9 and the three-phase asynchronous motor I6 and the sine filter 5.

[0033] In this embodiment, a fuse 4 is installed in the line between the P output terminal of the system asynchronous motor drive inverter 1 and the P input terminal of the inverter unit 3; a DC bus is installed in the line between the N output terminal of the system asynchronous motor drive inverter 1 and the N input terminal of the inverter unit 3.

[0034] In this embodiment, a current sensor 10 and a voltage sensor 11 are installed on the line between the output end of the inverter unit 3 and the input end of the sine filter 5 .

[0035] In the present embodiment, the test platform 15 is made of cast iron material, and a T-slot is provided thereon, in which a movable seat for supporting the three-phase asynchronous motor I6, the three-phase asynchronous motor II7 or the diverter 13 is slidably installed. A plurality of adjusting pads 12 for adjusting the height are provided on the upper side of the movable seat, and the horizontal height position of the shaft body of each motor is made flush by adjusting the number of adjusting pads, and the central axes of the output shafts of the two relative motors coincide with each other. In order to facilitate the contact of the three-phase asynchronous motor I6, the three-phase asynchronous motor II7 and the diverter 13 with the adjusting pads 12, the bottom side thereof can be set to a plane structure. The three-phase asynchronous motor I6, the three-phase asynchronous motor II7 and the diverter 13 are fixed to the corresponding movable seat by screws penetrating the adjusting pads.

[0036] In this embodiment, the inner ends of the input shaft and the output shaft in the steering gear 13 are transmission connected via an umbrella-shaped steering gear set.

[0037] In this embodiment, the coupling 14 is a diaphragm coupling using a flexible connection, which has the advantages of easy installation, long service life, and the ability to allow a certain degree of coaxiality deviation.

[0038] This embodiment also provides a test method for the frequency converter test system, comprising the following steps:

[0039] S1, press the start button, the contactor 2 is closed, the asynchronous motor drive system inverter 1 is powered, and transmits the DC current to the power inverter unit 3 through the PN line. The inverter unit 3 inverts the current and outputs the three-phase AC current to the sine wave filter 5 for filtering and shaping, and transmits the filtered current to the asynchronous motor drive inverter 9;

[0040] S2, running the asynchronous motor drive inverter 9, the motor drive inverter 9 outputs current to the three-phase asynchronous motor I6, and the three-phase asynchronous motor I6 is switched by disconnecting and closing the contactor 2. At this time, the current to the three-phase asynchronous motor I6 runs alone or simultaneously;

[0041] S3, the three-phase asynchronous motor I6 drives the three-phase asynchronous motor II7 to rotate, generating current, and the three-phase asynchronous motor 7 acts as a generator to generate and transmit the three-phase current to the UVW end of the asynchronous motor drive system inverter 1, and the asynchronous motor drive system inverter 1 transmits the DC current to the electric inverter unit 3 through the PN line, forming an internal current cycle;

[0042] S4, run the asynchronous motor drive system inverter 1, the UVW end of the asynchronous motor drive system inverter 1 will convert the receiving current into the output current, drive the three-phase asynchronous motor II7 to run, at this time the three-phase asynchronous motor II7 acts as a load, and realizes the test of the performance of the asynchronous motor drive inverter 9.

[0043] A specific application of this embodiment is: the P and N output terminals of the asynchronous motor drive inverter 1 of the system of this embodiment are connected to the input terminal of the inverter unit 3, the output terminal of the inverter unit 3 is connected to the input terminal of the sine filter 5, the output terminal of the sine filter 5 is connected to the input terminal of the asynchronous motor drive inverter 9 to be tested, and then connected to the input terminal of the three-phase asynchronous motor II7, so that the three-phase electricity can be internally circulated between the motor and the inverter without being connected to the power grid, thereby reducing interference to the power grid, and at the same time, energy recycling achieves the purpose of energy saving and environmental protection.

[0044] The preferred embodiments of the present invention disclosed above are only useful to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A frequency converter testing system, characterized in that: The frequency converter test system comprises a control cabinet, an asynchronous motor drive system frequency converter (1), an inverter unit (3), a sine wave filter (5), a three-phase asynchronous motor I (6), a three-phase asynchronous motor II (7), a motor torque sensor (8), an asynchronous motor drive frequency converter (9), a steering gear (13), a coupling (14) and a test platform (15); the asynchronous motor drive system frequency converter (1) is powered and controlled by the control cabinet, the control cabinet is powered by a 380V power grid connected to its input terminal, and the asynchronous motor drive frequency converter (9) is electrically connected to the input terminal of the asynchronous motor drive system frequency converter (1). ) is connected to the control cabinet through a test fixture, the P and N output terminals of the asynchronous motor drive system inverter (1) are connected to the P and N input terminals of the inverter unit (3), the output terminal of the inverter unit (3) is connected to the input terminal of the sine filter (5), the output terminal of the sine filter (5) is connected to the input terminal of the asynchronous motor drive inverter (9) under test, the output terminal of the asynchronous motor drive system inverter (1) is connected to the three-phase asynchronous motor II (7), and the output terminal of the asynchronous motor drive inverter (9) is connected to the three-phase asynchronous motor I (6); The test platform (15) is equipped with two steering gears (13), three three-phase asynchronous motors I (6) and one three-phase asynchronous motor II (7), wherein one of the steering gears (13) comprises an input shaft and two mutually perpendicular output shafts, and the input shaft is connected to the output shaft of the three-phase asynchronous motor II (7) through a coupling (14) and a motor torque sensor (8), one of the output shafts is connected to the output shaft of one three-phase asynchronous motor I (6) through a coupling (14), and the other output shaft is connected to the output shaft of another steering gear (13) through a coupling (14), and the other steering gear (13) further comprises two mutually flush output shafts, and the output shafts are respectively connected to the output shafts of the other two three-phase asynchronous motors I (6) through couplings (14); A contactor (2) is installed on the power supply circuit of the asynchronous motor drive system inverter (1) and the circuit between the asynchronous motor drive inverter (9) and the three-phase asynchronous motor I (6) and the sine filter (5); A fuse (4) is installed on the line between the P output end of the frequency converter (1) of the asynchronous motor drive system and the P input end of the inverter unit (3); and a DC bus is installed on the line between the N output end of the frequency converter (1) of the asynchronous motor drive system and the N input end of the inverter unit (3).

2. The frequency converter testing system according to claim 1, characterized in that: A current sensor (10) and a voltage sensor (11) are installed on the line between the output end of the inverter unit (3) and the input end of the sine filter (5).

3. The frequency converter testing system according to claim 1, characterized in that: The test platform (15) is provided with a T-shaped slot, in which a movable seat for supporting a three-phase asynchronous motor I (6), a three-phase asynchronous motor II (7) or a steering gear (13) is slidably mounted.

4. The frequency converter testing system according to claim 3, characterized in that: A plurality of adjustment gaskets (12) for adjusting the height are arranged on the upper side of the movable seat. By adjusting the number of the adjustment gaskets, the horizontal height positions of the shaft bodies of the respective motors are aligned, and the central axes of the output shafts of the two opposing motors coincide with each other.

5. The frequency converter testing system according to claim 1, characterized in that: The inner ends of the input shaft and the output shaft in the steering gear (13) are transmission connected via an umbrella-shaped steering gear set.

6. The frequency converter testing system according to claim 1, characterized in that: The testing method of the frequency converter testing system comprises the following steps: S1, press the start button, the contactor (2) is closed, the asynchronous motor drive system inverter (1) is energized, and the DC current is transmitted to the power inverter unit (3) through the PN line. The inverter unit (3) inverts the current and outputs the three-phase AC current to the sine wave filter (5) for filtering and shaping, and transmits the filtered current to the asynchronous motor drive inverter (9); S2, running the asynchronous motor drive inverter (9), the motor drive inverter (9) outputs current to the three-phase asynchronous motor I (6), and the three-phase asynchronous motor I (6) is switched by opening and closing the contactor (2), at which time the current to the three-phase asynchronous motor I (6) runs alone or simultaneously; S3, the three-phase asynchronous motor I (6) drives the three-phase asynchronous motor II (7) to rotate, generating current, and the three-phase asynchronous motor II (7) acts as a generator to generate three-phase current and transmit it to the UVW terminal of the asynchronous motor drive system inverter (1), and the asynchronous motor drive system inverter (1) transmits the DC current to the power inverter unit (3) through the PN line, forming an internal current cycle; S4, running the asynchronous motor drive system inverter (1), the UVW end of the asynchronous motor drive system inverter (1) will convert the receiving current into the output current, driving the three-phase asynchronous motor II (7) to run. At this time, the three-phase asynchronous motor II (7) serves as a load to achieve the test of the performance of the asynchronous motor drive inverter (9).

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