Power unit test equipment

Abstract

The utility model discloses a power unit test device, which is used for meeting the test requirement of a high-power power unit. The power unit test equipment comprises a voltage conversion circuit, a soft start circuit, a load circuit, a programmable logic controller and a main control board, the voltage conversion circuit is connected with the soft start circuit through at least two test branches which are connected in parallel; the soft start circuit is connected between the voltage conversion circuit and the input end of the tested power unit and is used for soft start of the test equipment; the load circuit is connected with the output end of the tested power unit, and the maximum support power of the load circuit is greater than the preset power; the programmable logic controller is used for receiving a test instruction input from the outside, issuing the test instruction to the main control board and controlling the on-off state of each contactor in the test equipment according to the test state; and the main control board is used for issuing a test instruction to the tested power unit according to the received test instruction issued by the programmable logic controller, and collecting the operation parameters of the tested power unit and the state of the fault flag bit.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, in particular to a power unit testing device. Background Art

[0002] With the continuous development of power electronics technology, medium voltage inverters have been widely used in the fields of electricity, transportation, etc.

[0003] The power unit is an important component of the medium voltage inverter. In order to ensure the stable operation of the medium voltage inverter, there are high requirements for the performance of the power unit. Therefore, testing the power unit is essential.

[0004] Currently, the power unit testing equipment for medium voltage inverters can only test small power units and cannot meet the testing requirements for large power units. Utility Model Content

[0005] The utility model provides a power unit testing device, which is used to meet the testing requirements of high-power power units.

[0006] The utility model provides a power unit test device, comprising: a voltage conversion circuit, a soft start circuit, a load circuit, a programmable logic controller (PLC), and a main control board; wherein:

[0007] The voltage conversion circuit is connected to the three-phase AC mains and is connected to the soft start circuit via at least two test branches connected in parallel, and the test voltages corresponding to the at least two test branches are different;

[0008] The soft start circuit is connected between the voltage conversion circuit and the input terminal of the power unit under test, and is used for soft starting the test equipment;

[0009] The load circuit is connected to the output end of the power unit under test, and is used to provide a resistive load and an inductive load, and the maximum supported power of the load circuit is greater than a preset power;

[0010] The programmable logic controller is connected to the voltage conversion circuit, the soft start circuit, and the load circuit, and is used to receive an external test instruction, send the test instruction to the main control board, and control the switch state of each contactor in the test device according to the test state;

[0011] The main control board is connected to the power unit under test for communication and information exchange with the power unit under test, and is used to send test instructions to the power unit under test according to the test instructions received from the programmable logic controller, and collect the operating parameters of the power unit under test and the status of the fault flag.

[0012] In the above-mentioned power unit testing equipment, the load circuit includes resistive load and inductive load. Different output currents can be provided through different load combinations to meet different power testing requirements. Specifically, when performing aging tests on high-power power units, a larger output current can be combined to perform aging tests on them to meet the testing requirements of high-power power units.

[0013] In a possible implementation, the load circuit includes a switching circuit, a resistive load cabinet and an inductive load cabinet, the resistive load cabinet and the inductive load cabinet are connected in parallel, and the switching circuit is connected between a common end of the resistive load cabinet and the resistive load cabinet and an output end of the power unit under test.

[0014] In one possible implementation, the switching circuit includes a first switching branch and a second switching branch connected in parallel, the first switching branch includes a first contactor and a first Hall current sensor, the second switching branch includes a second contactor and a second Hall current sensor, wherein the sampling currents of the first Hall current sensor and the second Hall current sensor are different.

[0015] In the above-mentioned power unit testing equipment, two switch branches are set, a corresponding Hall current sensor is set in each switch branch, and the sampling currents of the two Hall current sensors are different, so that different Hall current sensors can be used for current sampling for different output currents, avoiding the problem of large errors when high-current-level Hall current sensors sample small currents.

[0016] In a possible implementation manner, the resistance load cabinet includes a plurality of resistance branches connected in parallel, and each resistance branch includes at least one resistor and at least one contactor.

[0017] In a possible implementation manner, the inductive load cabinet includes a plurality of inductive branches connected in parallel, and each inductive branch includes at least one inductor and at least one contactor.

[0018] In a possible implementation manner, the voltage conversion circuit is connected to the soft start circuit via a first test branch and a second test branch connected in parallel, and the second test branch includes a step-up transformer.

[0019] In a possible implementation manner, the first test branch includes a third contactor, the third contactor is connected between the first circuit breaker and the soft start circuit, and the first circuit breaker is connected between the voltage conversion circuit and the three-phase AC mains.

[0020] In a possible implementation, the second test branch includes: a second circuit breaker, a step-up transformer, a fourth contactor and a fifth contactor, wherein the fourth contactor and the fifth contactor are connected in parallel and then connected in series with the second circuit breaker and the step-up transformer between the first circuit breaker and the soft start circuit, and the step-up transformer is connected to the soft start circuit through the fourth contactor and the fifth contactor, respectively.

[0021] In a possible implementation, the soft start circuit includes a soft start resistor and a sixth contactor connected in parallel, wherein when the sixth contactor is opened, the soft start resistor is connected to the circuit, and when the sixth contactor is closed, the soft start resistor is short-circuited.

[0022] In a possible implementation manner, the voltage conversion circuit further includes:

[0023] A first power supply branch, used to obtain the voltage between any phase of the three-phase AC mains and the neutral line to power the display and the instrument included in the test equipment;

[0024] The second power supply branch is used to convert the voltage of the first power supply branch into a specified DC voltage to supply power to the main control board. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic diagram of the structure of a power unit testing device provided by an embodiment of the utility model;

[0027] Figure 2 A schematic diagram of a load circuit provided by an embodiment of the utility model;

[0028] Figure 3 A schematic diagram of the structure of a switch circuit provided by an embodiment of the utility model;

[0029] Figure 4 A schematic diagram of the structure of a resistance load cabinet provided by an embodiment of the utility model;

[0030] Figure 5 A schematic diagram of the structure of an inductive load cabinet provided in an embodiment of the utility model;

[0031] Figure 6 A schematic diagram of the structure of a voltage conversion circuit provided by an embodiment of the utility model;

[0032] Figure 7 A schematic diagram of the structure of a soft start circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] In the description of the embodiments of the present invention, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; the “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present invention, “multiple” refers to two or more than two.

[0035] In the following, the terms "first", "second", "third", "fourth", "fifth", "sixth" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", ... "sixth", may explicitly or implicitly include one or more of the features.

[0036] Before introducing the power unit testing device provided by the embodiment of the present utility model, in order to facilitate understanding, the technical background of the embodiment of the present utility model is first introduced in detail below.

[0037] With the continuous development of power electronics technology, medium voltage inverters have been widely used in the fields of electricity, transportation, etc.

[0038] The power unit is an important component of the medium voltage inverter. In order to ensure the stable operation of the medium voltage inverter, there are high requirements for the performance of the power unit. Therefore, testing the power unit is essential.

[0039] Currently, the power unit testing equipment for medium voltage inverters can only test small power units and cannot meet the testing requirements for large power units.

[0040] In view of this, an embodiment of the utility model provides a power unit test device, including: a voltage conversion circuit, a soft start circuit, a load circuit, a programmable logic controller, and a main control board; wherein the voltage conversion circuit is connected to a three-phase AC mains, and is connected to the soft start circuit through at least two test branches connected in parallel, and the test voltages corresponding to the at least two test branches are different; the soft start circuit is connected between the voltage conversion circuit and the input end of the power unit under test, and is used for soft starting the test device; the load circuit is connected to the output end of the power unit under test, and is used to provide a resistive load and an inductive load, and the maximum supported power of the load circuit is greater than a preset power; the programmable logic controller is connected to the voltage conversion circuit, the soft start circuit, and the load circuit, and is used to receive a test instruction input from the outside, send the test instruction to the main control board, and control the switch state of each contactor in the test device according to the test state; the main control board exchanges information with the power unit under test, and is used to send a test instruction to the power unit under test according to the test instruction sent by the programmable logic controller, and collect the operating parameters of the power unit under test and the state of the fault flag.

[0041] Different load combinations in the load circuit can provide different output currents to meet different power test requirements. Specifically, when performing aging tests on high-power power units, a larger output current can be combined to perform aging tests on them to meet the test requirements of high-power power units.

[0042] After introducing the background technology of the embodiment of the utility model, the power unit testing device provided by the embodiment of the utility model is described in detail below in combination with specific embodiments.

[0043] like Figure 1 As shown, a power unit testing device 10 provided by an embodiment of the utility model includes: a voltage conversion circuit 110 , a soft start circuit 111 , a load circuit 112 , a programmable logic controller 113 , and a main control board 114 .

[0044] The voltage conversion circuit 110 is connected to the three-phase AC mains, and is connected to the soft start circuit 111 through at least two test branches connected in parallel, and the test voltages corresponding to the at least two test branches are different.

[0045] In a specific implementation, among at least two test branches, one test branch may not be provided with a transformer, and other test branches may be provided with transformers of different specifications, so that the test voltages corresponding to the various test branches are different.

[0046] The soft start circuit 111 is connected between the voltage conversion circuit 110 and the input terminal of the power unit under test, and is used for soft starting the test device 10 .

[0047] The load circuit 112 is connected to the output end of the power unit under test, and is used to provide a resistive load and an inductive load, and the maximum supported power of the load circuit 112 is greater than a preset power.

[0048] The preset current threshold can be set according to design requirements. For example, the preset current threshold can be set to 1300A or 1400A.

[0049] The programmable logic controller 113 is connected to the voltage conversion circuit 110, the soft start circuit 111, and the load circuit 112, and is used to receive test instructions input from the outside (for example, an external terminal device, a computer, etc.), send the test instructions to the main control board 114, and control the switching state of each contactor in the test equipment 10 according to the test state.

[0050] The main control board 114 is connected to the power unit under test for information exchange with the power unit under test, and is used to send test instructions to the power unit under test according to the test instructions sent by the programmable logic controller 113, and collect the operating parameters and fault flag status of the power unit under test.

[0051] When implementing it, Figure 2 As shown, the load circuit 112 includes a switch circuit 1121, a resistive load cabinet 1122 and an inductive load cabinet 1123. The resistive load cabinet 1122 and the inductive load cabinet 1123 are connected in parallel, and the switch circuit 1121 is connected between the common end of the resistive load cabinet 1122 and the resistive load cabinet 1123 and the output end of the power unit under test.

[0052] Among them, Figure 3 As shown, the switch circuit 1121 includes a first switch branch and a second switch branch connected in parallel, the first switch branch includes a first contactor 30 and a first Hall current sensor 31, and the second switch branch includes a second contactor 32 and a second Hall current sensor 33, wherein the sampling currents of the first Hall current sensor 31 and the second Hall current sensor 33 are different.

[0053] In the above power unit test equipment, two Hall current sensors are provided, and the sampling currents of the two Hall current sensors are different, so that different Hall current sensors can be used for current sampling for different output currents, avoiding the problem of large errors when high current level Hall current sensors sample small currents.

[0054] For example, the sampling current of the first Hall current sensor 31 is 400A, and the sampling current of the second Hall current sensor 33 is 1600A. When the output current is less than 400A, the first switch branch is controlled to be turned on, and the second switch branch is turned off, and the first Hall current sensor 31 is used to collect current. When the output current is greater than 400A, the first switch branch is controlled to be turned off, and the second switch branch is turned on, and the second Hall current sensor 33 is used to collect current.

[0055] In a specific implementation, the resistance load cabinet 1122 includes a plurality of resistance branches connected in parallel, and each resistance branch includes at least one resistor and at least one contactor.

[0056] In one example, if Figure 4 As shown, the resistor load cabinet includes 12 resistor branches connected in parallel, each resistor branch includes a resistor and a contactor, wherein the 12 resistors include 2 750Ω resistors, 2 80Ω resistors, and 8 10Ω resistors.

[0057] In a specific implementation, the inductive load cabinet 1123 includes a plurality of inductive branches connected in parallel, and each inductive branch includes at least one inductor and at least one contactor.

[0058] In one example, if Figure 5 As shown, the inductive load cabinet includes 11 inductive branches connected in parallel, each of which includes at least one inductor and at least one contactor, wherein the 12 inductive branches include 9 inductive branches with a rated current of 150A, 1 inductive branch with a rated current of 50A, and 1 inductive branch with a rated current of 25A.

[0059] It should be noted that the contactor mentioned in the embodiment of the present utility model may also use a relay, and the embodiment of the present utility model is described by taking the contactor as an example.

[0060] When implementing it, Figure 6 As shown, the voltage conversion circuit 110 is connected to the soft start circuit 111 through the first test branch and the second test branch connected in parallel, and the second test branch includes a step-up transformer. The first test branch includes a third contactor 61, which is connected between the first circuit breaker 62 and the soft start circuit, and the first circuit breaker 62 is connected between the voltage conversion circuit 110 and the three-phase AC mains. The second test branch includes: a second circuit breaker 63, a step-up transformer 64, a fourth contactor 65 and a fifth contactor, wherein the fourth contactor and the fifth contactor are connected in parallel, and are connected in series with the second circuit breaker and the step-up transformer 66 between the first circuit breaker 62 and the soft start circuit 111, and the step-up transformer 64 is connected to the soft start circuit 111 through the fourth contactor 65 and the fifth contactor 66, respectively.

[0061] Of course, in practical applications, the voltage conversion circuit 111 also includes: a first power supply branch, which is used to take the voltage between any phase of the three-phase AC mains and the neutral line to power the display and instrument included in the test equipment; a second power supply branch, which is used to convert the voltage of the first power supply branch into a specified DC voltage to power the main control board. Of course, the second power supply branch also needs to power the load fan, Hall sampling element, indicator light and travel switch.

[0062] When implementing it, Figure 7 As shown, the soft start circuit 111 includes a soft start resistor 71 and a sixth contactor 72 arranged in parallel, wherein when the sixth contactor 71 is opened, the soft start resistor 72 is connected to the circuit, and when the sixth contactor 71 is closed, the soft start resistor 72 is short-circuited.

[0063] It should be noted that, in actual applications, a voltage sampling sensor and a current sampling sensor may also be provided in the soft start circuit 111 to sample the input voltage and the input current respectively.

[0064] The power unit testing equipment provided by the embodiment of the utility model includes a resistive load and an inductive load in the load circuit. Different load combinations can provide different output currents to meet different power testing requirements. Specifically, when performing an aging test on a high-power power unit, a larger output current can be combined to perform the aging test on it, thereby meeting the testing requirements of the high-power power unit.

[0065] The power unit testing device provided in the embodiment of the utility model is generally described below, and the test-related logic of the aging test is briefly described.

[0066] The three-phase AC mains power (three-phase five-wire system, A phase, B phase, C phase, neutral line (N line), ground line (PE line)) is input through the first circuit breaker. The first circuit breaker can be set with an emergency power off switch (EPO), and then the B and N phases 220V can be used to power the control part of the test equipment.

[0067] After entering the line, the three-phase AC power is divided into two paths. One path is for the main test power, which passes through the third contactor, and the other path passes through the second circuit breaker and enters the step-up transformer (for example: 380V-722V transformer), and then is output through the fourth contactor and the fifth contactor respectively, connected to the rear end of the third contactor, and connected to the soft start circuit.

[0068] In the soft start circuit, the soft start resistor can be a ceramic resistor, and the sixth contactor is connected in parallel at both ends. The output of the soft start circuit is connected to the input side of the power unit under test after input voltage sampling and input current sampling. After the output voltage of the output end of the power unit under test is sampled, the first end is divided into two paths, one path is output through the first Hall current sensor and the first contactor, and the other path is output through the second Hall current sensor and the second contactor, and is connected to one end of the inductive load cabinet and the resistive load cabinet. The resistive load cabinet can be connected with 2 750Ω, 2 80Ω and 8 10Ω resistors (such as Figure 4 As shown), the inductive load cabinet adopts a splicing concept, which can connect 9 groups of rated current 150A inductors, 1 group of rated current 50A inductors, and 1 group of 25A inductors (as shown). Figure 5 As shown), it can splice a total output current of 1400A to meet the aging test requirements. The second end of the output of the power unit under test is connected to the other end of the inductive load cabinet and the resistive load cabinet.

[0069] In actual applications, since the power requirement is only used for aging inductance testing, the circuit breakers (first circuit breaker, second circuit breaker), contactors (third to sixth contactors) and other components selected at the front end of the input side of the power unit under test must meet the corresponding power levels. The output side must meet the maximum 1400A aging test requirement. One of the corresponding Hall current sensors (first Hall current sensor, second Hall current sensor) adopts 1600A specifications, and the first contactor and the second contactor are both used in parallel with three-phase 800A to meet the device usage requirements.

[0070] When conducting an aging test, the test program begins and first enters the preparation stage, sets some serial ports and communication parameters, and establishes communication with the main control board. Then, resets each contactor and reads the status of the travel switch of the test equipment. After confirmation, connects to a 380V AC power supply, turns on the fan, reads the UW and VW phase-to-phase voltages to determine whether the soft start is successful, and reads whether the optical fiber communication is normal.

[0071] First, the bypass test is selected. For non-bypass power units, this test link is skipped. If a bypass test is required, the test logic is entered, and an automatic bypass test instruction is issued to the power unit. After a delay, the automatic bypass test status is read. If the test fails, the program is terminated and the test equipment disconnects the mains power supply. If the test passes, the three-phase input status of the power unit is read and determined, and then the sampling data and fault flag of the power unit are read. This sampling step is performed three times, and the test passes if any one passes.

[0072] Secondly, enter the load test phase, connect the corresponding Hall current sensor, turn on the corresponding load cabinet fan, connect a 750Ω resistor, change the duty cycle of the drive waveform, generate the wave, read the output voltage, output current and input current, and make judgments based on the pre-set thresholds and seal the wave.

[0073] Then enter the rated load state of the power unit, connect a 10Ω resistor, change the duty cycle of the wave transmission, read the output voltage, output current and input current and make judgments, the main control board samples the fault flag and operating parameters of the power unit, and then adjusts the duty cycle according to the wave transmission state to the rated state of the output current, read the output voltage, output current and input current again, the main control board samples the fault flag and operating parameters of the power unit, and delays for 1 minute, repeats the above steps, after 3 delays and tests, if 1 test passes, this stage ends.

[0074] Then the 380V is switched to a 720V boost circuit, and the power unit is tested with load. A 750Ω load is connected, and the discharge state is entered after the test passes. When the output voltage enters the set value range, each contactor is reset and the test ends.

[0075] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A power unit testing device, characterized in that: include: Voltage conversion circuit, soft start circuit, load circuit, programmable logic controller, and main control board; wherein, The voltage conversion circuit is connected to the three-phase AC mains and is connected to the soft start circuit via at least two test branches connected in parallel, and the test voltages corresponding to the at least two test branches are different; The soft start circuit is connected between the voltage conversion circuit and the input terminal of the power unit under test, and is used for soft starting the test equipment; The load circuit is connected to the output end of the power unit under test, and is used to provide a resistive load and an inductive load, and the maximum supported power of the load circuit is greater than a preset power; The programmable logic controller is connected to the voltage conversion circuit, the soft start circuit, and the load circuit, and is used to receive an external test instruction, send the test instruction to the main control board, and control the switch state of each contactor in the test device according to the test state; The main control board is connected to the power unit under test for communication and information exchange with the power unit under test, and is used to send test instructions to the power unit under test according to the test instructions received from the programmable logic controller, and collect the operating parameters of the power unit under test and the status of the fault flag.

2. The device according to claim 1, characterized in that The load circuit includes a switch circuit, a resistive load cabinet and an inductive load cabinet, the resistive load cabinet and the inductive load cabinet are connected in parallel, and the switch circuit is connected between the common end of the resistive load cabinet and the resistive load cabinet and the output end of the power unit under test.

3. The device according to claim 2, characterized in that The switch circuit includes a first switch branch and a second switch branch connected in parallel, the first switch branch includes a first contactor and a first Hall current sensor, the second switch branch includes a second contactor and a second Hall current sensor, wherein the sampling currents of the first Hall current sensor and the second Hall current sensor are different.

4. The device according to claim 2, characterized in that The resistance load cabinet includes a plurality of resistance branches connected in parallel, and each resistance branch includes at least one resistor and at least one contactor.

5. The device according to claim 2, characterized in that The inductive load cabinet comprises a plurality of inductive branches connected in parallel, and each inductive branch comprises at least one inductor and at least one contactor.

6. The device according to any one of claims 1 to 5, characterized in that The voltage conversion circuit is connected to the soft start circuit via a first test branch and a second test branch connected in parallel, and the second test branch includes a step-up transformer.

7. The device according to claim 6, characterized in that The first test branch includes a third contactor, the third contactor is connected between the first circuit breaker and the soft start circuit, and the first circuit breaker is connected between the voltage conversion circuit and the three-phase AC mains.

8. The device according to claim 7, characterized in that The second test branch includes: a second circuit breaker, a step-up transformer, a fourth contactor and a fifth contactor, wherein the fourth contactor and the fifth contactor are connected in parallel and then connected in series with the second circuit breaker and the step-up transformer between the first circuit breaker and the soft start circuit, and the step-up transformer is connected to the soft start circuit through the fourth contactor and the fifth contactor, respectively.

9. The device according to any one of claims 1 to 5, characterized in that The soft start circuit comprises a soft start resistor and a sixth contactor which are arranged in parallel, wherein when the sixth contactor is opened, the soft start resistor is connected to the circuit, and when the sixth contactor is closed, the soft start resistor is short-circuited.

10. The device according to any one of claims 1 to 5, characterized in that The voltage conversion circuit further includes: A first power supply branch, used to obtain the voltage between any phase of the three-phase AC mains and the neutral line to power the display and the instrument included in the test equipment; The second power supply branch is used to convert the voltage of the first power supply branch into a specified DC voltage to supply power to the main control board.

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