Transformation ratio tester of power transformer

Abstract

The utility model discloses a transformation ratio tester of a power transformer, which belongs to a voltage tester and comprises a power amplification circuit used for being connected with a power supply, the power amplification circuit is connected with a transformation inverter, the transformation inverter is connected with a signal output relay module, and the signal output relay module is used for being connected with a high-voltage side of the power transformer. The transformation ratio tester further comprises a signal acquisition relay module, the signal acquisition relay module is connected to the low-voltage side of the power transformer, the signal acquisition relay module is connected to the differential acquisition circuit, the differential acquisition circuit is connected to the analog-to-digital conversion circuit through the operational amplifier circuit, and the analog-to-digital conversion circuit is connected to the single-chip microcomputer. A power amplification circuit connected with a power supply is designed and matched with a transformation inverter, so that the power supply can provide a measurement signal through a three-phase SPWM inverter circuit, after the measurement signal passes through a primary coil and a secondary coil of a tested power transformer, an acquired signal is transmitted to a single-chip microcomputer after differential acquisition amplification and analog-to-digital conversion, and then a three-phase transformation ratio test can be completed at a time.

Description

Technical Field

[0001] The utility model relates to a voltage tester, and more specifically, mainly relates to a transformation ratio tester for a power transformer. Background Art

[0002] Common power transformers need to undergo multiple rigorous tests before they are produced and put into use. However, the traditional ratio bridge is cumbersome to operate, the readings are not intuitive, and necessary conversions are required. The test result is only the value of one phase ratio, which affects the efficiency of power transformer testing. Therefore, it is necessary to study and improve the circuit structure of the existing ratio tester. Utility Model Content

[0003] One of the purposes of the present invention is to provide a power transformer ratio tester in view of the above-mentioned shortcomings, so as to solve the technical problems of similar ratio testers in the prior art, such as cumbersome operation, inconvenient reading, and single test results.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The utility model provides a power transformer ratio tester, comprising a power amplifier circuit for accessing a power supply, the power amplifier circuit being connected to a transformer inverter, the transformer inverter being used to access a signal output relay module, the signal output relay module being used to access the high-voltage side of the power transformer; the ratio tester also comprises a signal acquisition relay module, the signal acquisition relay module being used to access the low-voltage side of the power transformer, and the signal acquisition relay module being connected to a differential acquisition circuit, the differential acquisition circuit being connected to an analog-to-digital conversion circuit via an operational amplifier circuit, the analog-to-digital conversion circuit being connected to a single-chip microcomputer, the single-chip microcomputer being further connected to a signal output relay module, a signal acquisition relay module and a power amplifier circuit respectively; the signal output relay module comprises a plurality of relays connected in parallel, for combining output signals to the high-voltage side of the power transformer according to test requirements; the signal acquisition relay module also comprises a plurality of relays connected in parallel, for receiving the output signal passing through the power transformer.

[0006] As a preferred embodiment, a further technical solution is: a high-voltage side output control circuit is connected between the signal output relay module and the high-voltage side of the power transformer, and a low-voltage acquisition circuit is connected between the signal acquisition relay module and the low-voltage side of the power transformer.

[0007] A further technical solution is: the single-chip microcomputer is used to output an SPWM control signal to the power amplifier circuit, and control the on and off of the relays in the signal output relay module and the signal acquisition relay module, and receive the power transformer ratio test signal from the signal acquisition relay module through the differential acquisition circuit and the operational amplifier circuit.

[0008] A further technical solution is that the single chip microcomputer is also connected to a display screen, a Bluetooth module and a USB communication module respectively.

[0009] Compared with the prior art, one of the beneficial effects of the present invention is that: by designing a power amplifier circuit connected to a power supply and cooperating with a transformer inverter, a measurement signal can be provided by the power supply through a three-phase SPWM inverter circuit. After passing through the primary and secondary coils of the power transformer under test, the collected signal is transmitted to the single-chip microcomputer after analog-to-digital conversion, thereby completing the three-phase transformation ratio test at one time, making the transformation ratio test of the power transformer more convenient and quick. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic structural diagram for illustrating an embodiment of the utility model. DETAILED DESCRIPTION

[0011] The present invention will be further described below in conjunction with the accompanying drawings.

[0012] refer to Figure 1 As shown, one embodiment of the present invention is a power transformer ratio tester, including a power amplifier circuit for accessing a power supply, the power amplifier circuit is connected to a transformer inverter, the transformer inverter is used to access a signal output relay module, and the signal output relay module is used to access the high-voltage side of the power transformer; the ratio tester also includes a signal acquisition relay module, the signal acquisition relay module is used to access the low-voltage side of the power transformer, and the signal acquisition relay module is connected to a differential acquisition circuit, the differential acquisition circuit is connected to an analog-to-digital conversion circuit through an operational amplifier circuit, the analog-to-digital conversion circuit is connected to a single-chip microcomputer, and the single-chip microcomputer is also respectively connected to a signal acquisition relay module, a signal output relay module and a power amplifier circuit; the signal output relay module includes multiple parallel relays for combining output signals to the high-voltage side of the power transformer according to test requirements; the signal acquisition relay module also includes multiple parallel relays for receiving the output signal passing through the power transformer. In this embodiment, the aforementioned single-chip microcomputer is used to output an SPWM control signal to the power amplifier circuit, and control the on and off of the signal output relay module and the relay in the output relay module, and receive the transformation ratio test signal of the power transformer from the output relay module through the differential acquisition circuit and the operational amplifier circuit.

[0013] Furthermore, a high-voltage side output control circuit is connected between the signal output relay module and the test high-voltage side of the power transformer, and a low-voltage acquisition circuit is connected between the signal acquisition relay module and the low-voltage side of the power transformer. Figure 1 As shown, the single chip microcomputer is also connected to a display screen, a Bluetooth module and a USB communication module respectively.

[0014] In this embodiment, by designing a power amplifier circuit connected to the power supply and cooperating with the transformer inverter, the power supply can provide a measurement signal through the three-phase SPWM inverter circuit. After passing through the primary and secondary coils of the power transformer under test, the collected signal is transmitted to the single-chip microcomputer after analog-to-digital conversion, thereby completing the three-phase ratio test at one time, making the ratio test of the power transformer more convenient and quick.

[0015] As Figure 1 As described in the above embodiments, the power transformer ratio tester provided by the present invention is implemented as follows:

[0016] First, the power supply provides the measurement signal through a three-phase SPWM inverter circuit. Specifically, the microcontroller outputs the SPWM signal, which then passes through a subsequent power amplifier circuit and is then converted into a 50Hz AC signal by the instrument's internal transformer inverter. The signal is coupled by the processor and output with a controllable output range. The power amplifier circuit ensures a more stable output signal. The AO4264 is used in the inverter circuit, along with specially designed peripheral components, to achieve higher efficiency and output power than conventional inverter circuits.

[0017] The measurement signal is output through the high-voltage side signal relay control circuit and controlled by different combinations of 12 relays. For different wiring and different phase tests, the output signal needs to be combined to the corresponding interface of the transformer under test. The transformer ratio under test can be tested. The required wiring modifications are automatically completed by the instrument through the relay, and one-click testing can be performed when testing the parameters of the transformer under test.

[0018] The output signal from the high-voltage side output signal relay control circuit passes through the primary and secondary coils of the transformer under test, then through the low-voltage side signal acquisition relay circuit. Six relays control the signal reception, automatically switching the signal input port when the instrument requires individual group tests, allowing for automated completion of different group tests. The relay modules for output and acquisition signals are controlled by a single-chip microcomputer, enabling single-button control and complete testing of all transformer parameters. This is a more intelligent and automated approach compared to conventional ratio testers that require manual wiring modification to prevent test interference.

[0019] The collected signal is differentially collected by a high-precision operational amplifier circuit, and after passing through the analog-to-digital conversion circuit, the data is transmitted to the microcontroller for processing, calculation and display.

[0020] The meter has a built-in Bluetooth module that allows Bluetooth communication with mobile phone software and can also be connected to a Bluetooth printer to print test data in real time. The meter also has a built-in USB communication circuit that supports USB flash drive data export and can also be connected to a host computer software to read meter data.

[0021] In order to facilitate those skilled in the art to more easily implement the present invention, the above-mentioned three-phase SPWM inverter circuit can refer to the document "[1] Nie Junfei, Luo Ting, Zou Luhua, et al. Design of SPWM three-phase inverter system based on STM32 [J]. Journal of Shaoyang University (Natural Science Edition), 2019, 16(02): 15-21". The differential acquisition circuit and the operational amplifier circuit can be transplanted using existing circuits on the market; the inventor of the transformer inverter purchased a finished transformer inverter from Guangzhou Pinyou Electronics Co., Ltd. during the experiment. The model of the above-mentioned single-chip computer is STM32F103RCT6.

[0022] In addition to the above, it should be noted that references to "one embodiment," "another embodiment," "an embodiment," and the like in this specification refer to specific features, structures, or characteristics described in conjunction with that embodiment as being included in at least one embodiment generally described in this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in conjunction with any embodiment, it is intended that such feature, structure, or characteristic, when implemented in conjunction with other embodiments, also fall within the scope of the present invention.

[0023] Although the present invention has been described herein with reference to a number of illustrative embodiments thereof, it will be understood that numerous other modifications and implementations may be devised by those skilled in the art that fall within the scope and spirit of the principles disclosed herein. More specifically, within the scope of the present disclosure, the drawings, and the claims, numerous variations and modifications may be made to the components and / or arrangement of the subject combination arrangement. In addition to variations and modifications to the components and / or arrangement, other uses will also be apparent to those skilled in the art.

Claims

1. A power transformer ratio tester, comprising a power amplifier circuit for accessing a power supply, characterized in that: The power amplifier circuit is connected to a transformer inverter, the transformer inverter is used to connect to a signal output relay module, and the signal output relay module is used to connect to the high-voltage side of the power transformer; The turns ratio tester also includes a signal acquisition relay module, which is used to connect to the low-voltage side of the power transformer, and the signal acquisition relay module is connected to the differential acquisition circuit, the differential acquisition circuit is connected to the analog-to-digital conversion circuit through the operational amplifier circuit, the analog-to-digital conversion circuit is connected to the single-chip microcomputer, and the single-chip microcomputer is also respectively connected to the signal output relay module, the signal acquisition relay module and the power amplifier circuit; The signal output relay module includes a plurality of relays connected in parallel, which are used to combine and output signals to the high-voltage side of the power transformer according to test requirements; The signal acquisition relay module also includes a plurality of relays connected in parallel, which are used to receive the output signal passing through the power transformer.

2. The power transformer ratio tester according to claim 1, characterized in that: A high-voltage side output control circuit is connected between the signal output relay module and the high-voltage side of the power transformer, and a low-voltage acquisition circuit is connected between the signal acquisition relay module and the low-voltage side of the power transformer.

3. The power transformer ratio tester according to claim 1, characterized in that: The single chip microcomputer is used to output an SPWM control signal to the power amplifier circuit, and control the on and off of the relays in the signal output relay module and the signal acquisition relay module, and receive the transformation ratio test signal of the power transformer from the signal acquisition relay module through the differential acquisition circuit and the operational amplifier circuit.

4. The power transformer ratio tester according to claim 1, characterized in that: The single chip microcomputer is also connected to a display screen, a Bluetooth module and a USB communication module respectively.

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