AC / DC test set

Abstract

The utility model relates to the field of electric power test equipment, concretely to an AC-DC test instrument, contain box and power module, be equipped with cascade voltage regulation circuit, high frequency step -up transformer, autotransformer, step -up transformer, voltage doubler rectifier circuit and control unit in the box, be equipped with operating panel, high pressure output end and high pressure output line on the box, power module is connected with high frequency step -up transformer and autotransformer respectively through cascade voltage regulation circuit, the direct current voltage of power module is inverted into the alternating voltage of different frequency through cascade voltage regulation circuit and is input to high frequency step -up transformer or autotransformer, the alternating voltage is boosted through high frequency step -up transformer, and then becomes direct current high pressure through voltage doubler rectifier circuit, autotransformer boosts the alternating voltage of cascade voltage regulation circuit, and then is boosted output AC high pressure through step -up transformer, has realized to the DC and AC test detection function of complex line, has saved the test cost.

Description

Technical Field

[0001] This utility model relates to the field of power testing equipment, and in particular to an AC / DC test instrument. Background Technology

[0002] Before energizing 10kV overhead lines or during regular inspections, DC testers are often used to test the DC high voltage input to the line. This can quickly and effectively identify faults such as insulation deterioration, short circuits, and grounding. However, during the test, the inductive equipment such as current transformers and transformers in the line under test need to be disconnected. Otherwise, the DC high voltage will leak directly to the ground. For these inductive devices in the line, other AC withstand voltage equipment needs to be used for testing. However, with an AC tester, it is not necessary to disconnect the inductive equipment in the line, and the line under test can be directly pressurized for testing.

[0003] However, cables in overhead lines are capacitive test objects. The capacitive reactance of the cable decreases with increasing cable length, and the greater the capacitive current consumed, the higher the power consumption. To reduce the power consumption of the instrument and make it lighter, in actual operation, frequency converter resonance or parallel reactors are used at the instrument output for compensation to increase the voltage output of the instrument or reduce the capacitive current in the cable, thereby reducing the power consumption of the instrument. All of these methods require connecting additional equipment to carry out the test, which is heavy and inconvenient to transport. Furthermore, for testing complex circuits, to improve testing efficiency, DC and AC test instruments are often used interchangeably, but this means carrying two test instruments, increasing testing costs.

[0004] In view of this, the present invention proposes an AC / DC test instrument to solve the above-mentioned technical problems. Utility Model Content

[0005] The purpose of this utility model is to provide an AC / DC test transmitter to solve the problems in the background art, such as the increased testing cost and the inconvenience of carrying two test transmitters with different outputs for DC and AC test transmission in the testing of complex circuits, as well as the large weight of the external equipment of the AC test transmitter.

[0006] To achieve the above objectives, this utility model provides an AC / DC test instrument, comprising: a housing and a power module. The housing is equipped with a cascaded voltage regulating circuit, a high-frequency step-up transformer, an autotransformer, a step-up transformer, a voltage multiplier rectifier circuit, and a measurement and control unit. The housing is equipped with an operation panel, a high-voltage output terminal, and a high-voltage output line. The power module is connected to the high-frequency step-up transformer and the autotransformer via the cascaded voltage regulating circuit. The autotransformer is connected to the high-voltage output terminal via the step-up transformer. The high-frequency step-up transformer is connected to the high-voltage output terminal via the voltage multiplier rectifier circuit. The measurement and control unit is connected to the cascaded voltage regulating circuit, the high-voltage output terminal, and the operation panel. The high-voltage output line is connected to the high-voltage output terminal.

[0007] Preferably, in the above technical solution, the cascaded voltage regulation circuit includes a transistor driving circuit, a first-stage full-bridge inverter circuit, and a second-stage full-bridge inverter circuit. The transistor driving circuit is connected to the measurement and control unit. The first-stage full-bridge inverter circuit and the second-stage full-bridge inverter circuit are respectively connected to the transistor driving circuit. The power supply module is respectively connected to the first-stage full-bridge inverter circuit and the second-stage full-bridge inverter circuit. The first-stage full-bridge inverter circuit and the second-stage full-bridge inverter circuit are connected.

[0008] Preferably, the above technical solution further includes a DC switching switch and an AC switching switch. One end of the DC switching switch and the AC switching switch are respectively connected in parallel to the output terminals of the first-stage full-bridge inverter circuit and the second-stage full-bridge inverter circuit. The other end of the DC switching switch is connected to the input terminal of the high-frequency step-up transformer, and the other end of the AC switching switch is connected to the input terminal of the autotransformer.

[0009] Preferably, the above technical solution further includes an LC filter circuit, which is connected in series between the AC switching switch and the autotransformer.

[0010] Preferably, in the above technical solution, the high-voltage output terminal includes a DC output terminal, an AC output terminal, and a grounding terminal; the voltage multiplier rectifier circuit is connected to the DC output terminal; the step-up transformer is connected to the AC output terminal; and the grounding terminal is connected to the outer shell of the enclosure.

[0011] Preferably, in the above technical solution, the measurement and control unit includes a microcontroller, a discharge circuit, and a measurement circuit. The transistor driving circuit, the discharge circuit, and the measurement circuit are respectively connected to the microcontroller. The measurement circuit is respectively connected to the DC output terminal, the AC output terminal, and the ground terminal. The discharge circuit is respectively connected to the DC output terminal and the AC output terminal.

[0012] Preferably, in the above technical solution, the operation panel includes a display, an AC output button, a DC output button, a voltage adjustment knob, and a power socket. The display, AC output button, DC output button, and voltage adjustment knob are all connected to the microcontroller, and the power socket is connected to the power module.

[0013] Preferably, in the above technical solution, the power module is located in another box outside the main box, and the power module is a rechargeable battery or an AC220 to DC power supply.

[0014] Compared with existing technologies, this utility model has the following beneficial effects:

[0015] 1. This utility model inverts the DC voltage of the power module into a high-frequency AC voltage through a cascaded voltage regulating circuit. The voltage is then boosted by a high-frequency step-up transformer and rectified by a voltage doubler rectifier circuit to obtain a high-voltage DC signal. The cascaded voltage regulating circuit then inverts the DC voltage of the power module into a power frequency AC voltage. After being boosted sequentially by an autotransformer and a step-up transformer, a high-voltage AC signal is obtained. This realizes both DC and AC output functions. Only one device is needed to complete the testing of inductive and capacitive devices in the circuit, reducing testing costs.

[0016] 2. The first-stage full-bridge inverter circuit of this utility model is connected to the second-stage full-bridge inverter circuit to form a cascaded structure. The output voltage of the cascaded voltage regulator circuit is the sum of the output voltages of the first-stage full-bridge inverter circuit and the second-stage full-bridge inverter circuit. By improving the output voltage capability of the power module, the turns ratio of the high-voltage side and the low-voltage side of the high-frequency step-up transformer and the autotransformer is reduced, thereby enabling the power of the high-frequency step-up transformer and the autotransformer to be reduced, thus reducing their size and material costs. Attached Figure Description

[0017] Figure 1 This is the overall electrical schematic diagram of this utility model.

[0018] Figure 2 This is the electrical schematic diagram of the cascaded voltage regulating circuit of this utility model.

[0019] Figure 3 This is a schematic diagram of the overall structure of this utility model.

[0020] In the diagram: 1—Box, 2—Grounding terminal, 3—DC output terminal, 4—AC output terminal, 5—Display, 6—AC output button, 7—DC output button, 8—Voltage adjustment knob, 9—Power socket, 10—High voltage output line, 100—Microcontroller, 101—Measurement circuit, 102—Power module, 103—Cascaded voltage regulation circuit, 104—Voltage doubler rectifier circuit, 105—LC filter circuit, 106—Discharge circuit, T1—High frequency step-up transformer, T2—Step-up transformer, T3—Autotransformer, CB1—DC switching switch, CB2—AC switching switch. Detailed Implementation

[0021] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, it should be understood that the scope of protection of this utility model is not limited to the specific embodiments.

[0022] refer to Figure 1 and Figure 3 An AC / DC test instrument includes a housing 1 and a power module 102. The housing 1 contains a cascaded voltage regulating circuit 103, a high-frequency step-up transformer T1, a voltage doubler rectifier circuit 104, an LC filter circuit 105, an autotransformer T3, and a step-up transformer T2. The housing 1 has an operation panel, a high-voltage output terminal, and a high-voltage output line 10. The high-voltage output terminal includes a grounding terminal 2, a DC output terminal 3, and an AC output terminal 4. The measurement and control unit includes a measurement circuit 101, a discharge circuit 106, a DC switching switch CB1, an AC switching switch CB2, and a microcontroller 100. The operation panel includes an AC output button 6, a DC output button 7, and a voltage regulating knob 8. The grounding terminal 2 is connected to the housing 1's outer shell, and the high-voltage output line 10 is connected to the high-voltage output terminal.

[0023] The power module 102 is connected to the cascaded voltage regulator circuit 103 via the power socket 9. The power module 102 is connected to the high-frequency step-up transformer T1 and the autotransformer T3 via the cascaded voltage regulator circuit 103. The cascaded voltage regulator circuit 103 is connected to the microcontroller 100. The cascaded voltage regulator circuit 103 is used to invert the DC voltage of the power module 102 into an AC voltage signal with adjustable frequency, and input it to the high-frequency step-up transformer T1 and the autotransformer T3 for voltage boosting. The AC voltage signal input to the high-frequency step-up transformer T1 is a high-frequency AC voltage signal, and the AC voltage signal input to the autotransformer T3 is a power frequency AC voltage signal. The power module 102 is a rechargeable battery module or an AC220V to DC power supply.

[0024] The high-frequency step-up transformer T1 is connected to the voltage doubler rectifier circuit 104, which is connected to the DC output terminal 3 of the high-voltage output terminal. The voltage doubler rectifier circuit 104 is used to rectify the high-frequency AC high-voltage signal output by the high-frequency step-up transformer T1 into a DC high-voltage signal. The maximum output DC voltage is 8-10kV and the maximum output current is 120mA.

[0025] Autotransformer T3 is connected to step-up transformer T2. Step-up transformer T2 is connected to AC output terminal 4 of the high-voltage output terminal. Autotransformer T3 is used to boost the power frequency AC voltage signal output by cascaded voltage regulating circuit 103 for the first time. Step-up transformer T2 is used to boost the output voltage of autotransformer T3 again. The maximum output AC voltage is 6-8kV and the maximum output current is 120mA.

[0026] The high-frequency step-up transformer T1 and the cascaded voltage regulating circuit 103 are connected through a DC switching switch CB1, and the autotransformer T3 and the cascaded voltage regulating circuit 103 are connected through an AC switching switch CB2. Both the DC switching switch CB1 and the AC switching switch CB2 are connected to the microcontroller 100. The microcontroller 100 switches the output of AC or DC voltage by controlling the switching of the AC switching switch CB2 or the DC switching switch CB1. In this embodiment, the DC switching switch CB1 and the AC switching switch CB2 are relay switch modules, and the microcontroller 100 is an STM32F103C8T6.

[0027] The LC filter circuit 105 is connected in series between the AC switching switch CB2 and the autotransformer T3. The LC filter circuit 105 is used to filter the AC voltage signal input to the autotransformer T3 by the cascaded voltage regulating circuit 103.

[0028] refer to Figure 2 The cascaded voltage regulation circuit 103 includes a transistor driver circuit, a first-stage full-bridge inverter circuit, and a second-stage full-bridge inverter circuit. The first-stage full-bridge inverter circuit and the second-stage full-bridge inverter circuit are connected. The microcontroller 100 is connected to the transistor driver circuit. The transistor driver circuit is connected to both the first-stage and second-stage full-bridge inverter circuits. The first-stage and second-stage full-bridge inverter circuits are connected to the power supply module 102. The transistor driver circuit generates an SPWM signal to drive the first-stage and second-stage full-bridge inverter circuits. The first-stage and second-stage full-bridge inverter circuits convert the DC voltage of the power supply module 102 into AC voltage. One end of the DC switching switch CB1 and the AC switching switch CB2 are connected in parallel to the output terminals of the first-stage and second-stage full-bridge inverter circuits, respectively.

[0029] Specifically, the output node 1 of the first-stage full-bridge inverter circuit is connected to the input node 3 of the second-stage full-bridge inverter circuit. The output node 2 of the first-stage full-bridge inverter circuit is connected to one input terminal of both the DC switching switch CB1 and the AC switching switch CB2. The output node 4 of the second-stage full-bridge inverter circuit is connected to one input terminal of both the DC switching switch CB1 and the AC switching switch CB2. The first-stage full-bridge inverter circuit consists of transistors Q1, Q2, Q3, and Q4, while the second-stage full-bridge inverter circuit consists of transistors Q5, Q6, Q7, and Q8. By cascading the first-stage and second-stage full-bridge inverter circuits, the output voltages of the first-stage and second-stage full-bridge inverter circuits are superimposed, resulting in the maximum output voltage of the cascaded voltage regulator circuit 103. , in , , The DC voltage of the power module 102 is increased, and the output voltage of the cascaded voltage regulating circuit 103 is improved. This can effectively reduce the winding ratio of the primary and secondary sides of the high-frequency step-up transformer T1 and the autotransformer T2, thereby reducing the power and volume of the high-frequency step-up transformer T1 and the autotransformer T2, and reducing the overall weight of the instrument.

[0030] The microcontroller 100 is connected to the measurement circuit 101, which is connected to the grounding terminal 2, the DC output terminal 3 and the AC output terminal 4 respectively. The measurement circuit 101 is used to measure the voltage and current signals of the grounding terminal 2, the DC output terminal 3 and the AC output terminal 4.

[0031] The microcontroller 100 is connected to the discharge circuit 106, which is connected to the DC output terminal 3 and the AC output terminal 4 respectively. The discharge circuit 106 is used for the instrument to reduce voltage and discharge after the test.

[0032] Display 5, AC output button 6, DC output button 7, and voltage adjustment knob 8 are all connected to microcontroller 100. AC output button 6 and DC output button 7 are used to switch between DC high voltage and AC high voltage output modes. Voltage adjustment knob 8 is used to adjust the output high voltage amplitude. Microcontroller 100 controls the output of cascaded voltage regulation circuit 103 according to the data of voltage adjustment knob 8, and performs closed-loop feedback regulation of cascaded voltage regulation circuit 103 by acquiring the voltage and current signals of DC output terminal 3 or AC output terminal 4 through measurement circuit 101. Microcontroller 100 monitors the voltage and current signals of grounding terminal 2, DC output terminal 3, and AC output terminal 4 through measurement circuit 101 to perform fault judgment, and controls display 5 to display the output voltage and judgment detection results.

[0033] The working process of this utility model is as follows:

[0034] When testing a line containing inductive equipment such as transformers and instrument transformers, the tester first disconnects these inductive devices from the line. Then, one end of the high-voltage output line 10 is connected to the DC output terminal 3, and the other end is connected to a metal component of the line. A grounding wire is used to connect to the grounding terminal 2. The tester presses the DC output button 7, closing the DC switching switch CB1, and uses the voltage adjustment knob 8 to perform a voltage boost operation. The microcontroller 100 automatically performs voltage boost, fault diagnosis, voltage reduction, and discharge operations, and displays the test results on the display 5. After completing the DC test, for testing inductive equipment disconnected from the line, one end of the high-voltage output line 10 is connected to the AC output terminal 4, and the other end is connected to the inductive device. The tester presses the AC output button 6, closing the AC switching switch CB2. Similarly, the voltage adjustment knob 8 is used to perform a voltage boost operation. The microcontroller 100 automatically performs voltage boost, fault diagnosis, voltage reduction, and discharge operations, and displays the test results on the display 5. Since the inductive device is disconnected from the circuit, and there is no capacitive current consumed by the circuit cable as a capacitive device, the output power of the instrument is greatly reduced. Therefore, only a sufficient AC high voltage output is needed to detect faults such as short circuits, grounding, and insulation defects in the inductive device.

[0035] This invention separates the testing of inductive and capacitive devices in the circuit. The inductive devices consume no capacitive current, resulting in low power requirements for the instrument. This avoids the problems of existing AC test instruments, which require additional equipment to conduct tests, are heavy, and inconvenient to transport. The instrument has both AC and DC output functions, and a single device can meet the testing needs of complex circuits, thus reducing testing costs.

[0036] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. An AC-DC test sender, comprising a box body and a power module, wherein the box body is internally provided with a high-frequency step-up transformer, an autotransformer, a step-up transformer, a voltage doubler rectifier circuit and a measurement and control unit, and the box body is externally provided with an operation panel, a high-voltage output end and a high-voltage output line, characterized in that, Also includes: The power module is connected to a high-frequency step-up transformer and an autotransformer via a cascaded voltage regulation circuit. The autotransformer is connected to the high-voltage output terminal via the step-up transformer. The high-frequency step-up transformer is connected to the high-voltage output terminal via a voltage multiplier rectifier circuit. The measurement and control unit is connected to the cascaded voltage regulation circuit, the high-voltage output terminal, and the operation panel. The high-voltage output line is connected to the high-voltage output terminal.

2. The AC / DC test delivery instrument according to claim 1, characterized in that, The cascaded voltage regulation circuit includes a transistor driving circuit, a first-stage full-bridge inverter circuit, and a second-stage full-bridge inverter circuit. The transistor driving circuit is connected to the measurement and control unit. The first-stage full-bridge inverter circuit and the second-stage full-bridge inverter circuit are respectively connected to the transistor driving circuit. The power supply module is connected to the first-stage full-bridge inverter circuit and the second-stage full-bridge inverter circuit. The first-stage full-bridge inverter circuit and the second-stage full-bridge inverter circuit are connected.

3. The AC / DC test delivery instrument according to claim 2, characterized in that, It also includes a DC switching switch and an AC switching switch. One end of the DC switching switch and the AC switching switch are respectively connected in parallel to the output terminals of the first-stage full-bridge inverter circuit and the second-stage full-bridge inverter circuit. The other end of the DC switching switch is connected to the input terminal of the high-frequency step-up transformer, and the other end of the AC switching switch is connected to the input terminal of the autotransformer.

4. The AC / DC test delivery instrument according to claim 3, characterized in that, It also includes an LC filter circuit, which is connected in series between the AC switching switch and the autotransformer.

5. The AC / DC test delivery instrument according to claim 2, characterized in that, The high-voltage output terminal includes a DC output terminal, an AC output terminal, and a grounding terminal. The voltage multiplier rectifier circuit is connected to the DC output terminal, the step-up transformer is connected to the AC output terminal, and the grounding terminal is connected to the outer shell of the enclosure.

6. The AC / DC test delivery instrument according to claim 5, characterized in that, The measurement and control unit includes a microcontroller, a discharge circuit, and a measurement circuit. The transistor driving circuit, the discharge circuit, and the measurement circuit are respectively connected to the microcontroller. The measurement circuit is respectively connected to the DC output terminal, the AC output terminal, and the ground terminal. The discharge circuit is respectively connected to the DC output terminal and the AC output terminal.

7. The AC / DC test delivery instrument according to claim 5, characterized in that, The measurement and control unit includes a microcontroller, a discharge circuit, and a measurement circuit. The transistor driving circuit, the discharge circuit, and the measurement circuit are respectively connected to the microcontroller. The measurement circuit is respectively connected to the DC output terminal, the AC output terminal, and the ground terminal. The discharge circuit is respectively connected to the DC output terminal and the AC output terminal.

8. The AC / DC test delivery instrument according to claim 1, characterized in that, The power module is located in another box outside the main enclosure, and the power module is a rechargeable battery or an AC220 to DC power supply.

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