Nonlinear resistance test system and tester

Abstract

The utility model discloses a non-linear resistance testing system, and relates to the technical field of resistance testing, the non-linear resistance testing system comprises a resistance measuring module and an analysis module which are connected with each other, and the resistance measuring module comprises a capacitor charging and discharging unit. The discharging control unit is selectively connected with the capacitor charging and discharging unit; the voltage stabilization output unit is connected with the discharging control unit; the capacitor charging and discharging unit is also selectively connected with the charging power supply, the voltage stabilization output unit is also connected with the resistor to be tested, and the analysis module is also connected with the resistor to be tested. The discharging control unit is used for controlling the discharging process of the capacitor charging and discharging unit, so that the capacitor charging and discharging unit discharges in a stepped characteristic mode, the synchronization time redundancy of voltage sampling and current sampling is increased, and then the accuracy of nonlinear resistance testing is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of resistance testing, in particular to a nonlinear resistance testing system and tester. BACKGROUND

[0002] In a power plant, a non-linear electric resistance is used as a magnetism-eliminating resistance of an excitation system, which is a key component for normal operation of a generator, and is responsible for providing a DC voltage for an excitation winding of the generator to maintain stability of output voltage of the generator.

[0003] The non-linear resistance shows unique resistance characteristics at different voltage levels. In the related art, in order to reduce the weight of a non-linear resistance tester, an energy storage capacitor is usually used to provide a test voltage for the non-linear resistance tester. However, since the discharge voltage of the capacitor continuously decreases in an exponential characteristic during discharging, if the data of the voltage and the current flowing through the non-linear resistance are not collected synchronously during resistance value testing, the continuously decreasing voltage or current will affect the accuracy of the non-linear resistance testing. CONTENT

[0004] The main purpose of the application is to provide a non-linear resistance testing system and tester, which aims to solve the technical problem that the discharging characteristics of the capacitor affect the accuracy of the non-linear resistance testing when the capacitor is used for power supply in the non-linear resistance testing system.

[0005] To achieve the above purpose, the application provides a non-linear resistance testing system, which comprises:

[0006] The resistance measuring module and the analysis module are connected to each other, the resistance measuring module comprises a capacitor charging and discharging unit, a discharging control unit selectively connected to the capacitor charging and discharging unit, and a stable voltage output unit connected to the discharging control unit;

[0007] The capacitor charging and discharging unit is further selectively connected to a charging power supply, the stable voltage output unit is further connected to a resistance to be tested, and the analysis module is further connected to the resistance to be tested.

[0008] In an embodiment, the capacitor charging and discharging unit comprises a charging and discharging capacitor and a charging and discharging switching circuit connected in sequence;

[0009] The charging and discharging capacitor is selectively connected to a power supply and the discharging control unit through the charging and discharging switching circuit;

[0010] The charging and discharging switching circuit is used for controlling charging or discharging of the charging and discharging capacitor.

[0011] In an embodiment, the discharging control unit comprises a sample and hold circuit, an input end of the sample and hold circuit is selectively connected to the capacitor charging and discharging unit, and an output end of the sample and hold circuit is connected to the stable voltage output unit.

[0012] In an embodiment, the sample-and-hold circuit comprises an input follower component, a sampling switch, a holding capacitor, a resistor and an output follower component connected in sequence;

[0013] The input follower component is selectively connected with the capacitor charging and discharging unit, the output of the input follower component is connected with the input of the sampling switch, the control end of the sampling switch is connected with the first square wave control signal, one end of the holding capacitor is connected with the output of the sampling switch, the other end of the holding capacitor is connected with the input of the output follower component through the resistor, the other end of the holding capacitor is grounded, and the output of the output follower component is connected with the voltage stabilizing output unit.

[0014] In an embodiment, the voltage stabilizing output unit comprises a voltage stabilizing isolation switch, wherein the input of the voltage stabilizing isolation switch is connected with the output of the discharging control unit, the output of the voltage stabilizing isolation switch is connected with the resistance to be measured, and the control end of the voltage stabilizing isolation switch is connected with the second square wave control signal.

[0015] In an embodiment, the analysis module comprises a resistance value analysis unit, an analog-to-digital conversion unit, a voltage acquisition unit and a current acquisition unit.

[0016] The resistance value analysis unit is connected with the analog-to-digital conversion unit, the analog-to-digital conversion unit is connected with the voltage acquisition unit and the current acquisition unit respectively, and the voltage acquisition unit and the current acquisition unit are both connected with the resistance to be measured.

[0017] In an embodiment, the analysis module further comprises a state switching unit, and the state switching unit is connected with the resistance measurement module.

[0018] In a second aspect, in order to achieve the above object, the present application further provides a nonlinear resistance tester, which is composed of the nonlinear resistance testing system.

[0019] The one or more technical solutions provided by the present application have at least the following technical effects:

[0020] The nonlinear resistance testing system provided by the present application utilizes the discharging control unit to realize the stepwise characteristic discharge of the voltage signal in the capacitor discharging process, and further utilizes the optimization of the voltage stabilizing output unit to make each step last for a certain time and the voltage remain unchanged in the time period, which increases the synchronization time redundancy of the voltage sampling and the current sampling, and further increases the accuracy of the nonlinear resistance testing. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the embodiments or the related art description will be briefly introduced as follows. Obviously, those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0023] Figure 1 A schematic diagram of module connection of a nonlinear resistance test system in the related art.

[0024] Figure 2 A schematic diagram of circuit structure of a resistance measurement module in the nonlinear resistance test system of the present application.

[0025] Figure 3 A comparison diagram of effects of discharge voltages in the nonlinear resistance test system of the present application.

[0026] The purposes, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0027] It should be understood that the specific embodiments described herein are merely intended to explain the technical solutions of the present application, and not to limit the present application.

[0028] In order to better understand the technical solutions of the present application, the following will be described in detail with reference to the drawings and specific embodiments.

[0029] The main solution of the embodiments of the present application is that the present application realizes the control of the change of the voltage signal in the capacitor discharge process through the discharge control unit, so that the voltage signal originally showing exponential characteristic decline is changed into a stepwise change characteristic.

[0030] In the related art, the non-linear resistance tester usually provides a test voltage through a direct current power supply. The main advantage of this design is high stability, which can provide continuous and stable voltage output. However, due to the large weight of the power supply, in order to reduce the weight of the non-linear resistance tester, an energy storage capacitor is also used to provide a test voltage for the non-linear resistance tester. In addition, the voltage variation characteristics of the capacitor during discharging can also meet the requirements of detecting the resistance value of the non-linear resistance under different voltage conditions. However, since the discharging voltage of the capacitor during discharging continuously decreases in an exponential characteristic, the voltage changes continuously and rapidly, which makes it difficult to synchronize the data collection of the voltage and current flowing through the non-linear resistance when performing resistance testing. The continuously decreasing voltage or current will affect the accuracy of the non-linear resistance test. The application utilizes a discharging control unit to realize the step characteristic discharging of the voltage signal during the discharging of the capacitor, so that each step lasts for a certain period of time and the voltage remains unchanged during this period of time. This increases the synchronization time redundancy of voltage sampling and current sampling, thereby increasing the accuracy of non-linear resistance testing.

[0031] In order to better understand the above technical solutions, the embodiments of the present application provide a non-linear resistance testing system, which is described with reference to Figure 1 , Figure 1 is a module connection diagram of the first embodiment of the non-linear resistance testing system of the present application.

[0032] In this embodiment, the non-linear resistance testing system includes a resistance measurement module and an analysis module connected to each other. The resistance measurement module includes a capacitor charging and discharging unit, a discharging control unit selectively connected to the capacitor charging and discharging unit, and a voltage stabilizing output unit connected to the discharging control unit. The capacitor charging and discharging unit is also selectively connected to a charging power supply, and the voltage stabilizing output unit is also connected to the resistance to be tested. The analysis module is also connected to the resistance to be tested. The discharging control unit is used to control the discharging process of the capacitor charging and discharging unit, so that the capacitor charging and discharging unit discharges in a step characteristic.

[0033] In this embodiment, the resistance measurement module is used to provide a test voltage for the resistance to be tested, and the analysis module is used to sample and analyze the voltage applied to the resistance to be tested and the current flowing through the resistance to be tested, and calculate the resistance value of the non-linear resistance under different voltage conditions. The resistance to be tested can be a pressure-sensitive resistor.

[0034] Specifically, during the resistance test, the capacitor charging and discharging unit is connected with the discharging control unit, the element providing voltage in the capacitor charging and discharging unit is a charging and discharging capacitor which can be charged and discharged, and it can be understood that when the capacitor is connected to the load for discharging, the discharging voltage presents an exponential characteristic of decline, the discharging control unit is used to adjust the discharging voltage presenting an exponential characteristic of decline into a discharging voltage presenting a stepped decline and output, and the voltage stabilizing output unit is connected with the discharging control unit and is used to stabilize the discharging voltage presenting a stepped decline output by the discharging control unit, so as to make the voltage of each step of the discharging voltage presenting a stepped decline as stable as possible within the step maintaining time.

[0035] It can be understood that by converting the discharging voltage presenting an exponential characteristic of decline into a discharging voltage presenting a stepped decline, the synchronization time redundancy of voltage sampling and current sampling can be increased, and thus the accuracy of the nonlinear resistance test is increased.

[0036] Further, referring to Figure 2 , Figure 2 a circuit connection structure diagram of one embodiment of the resistance measurement module is shown.

[0037] As shown in Figure 2 , in a feasible embodiment, the capacitor charging and discharging unit includes a charging and discharging capacitor C1 and a charging and discharging switching circuit K1 connected in sequence. The charging and discharging capacitor C1 is selectively connected with the power supply E1 and the discharging control unit through the charging and discharging switching circuit K1. The charging and discharging switching circuit K1 is used to control the charging or discharging of the charging and discharging capacitor.

[0038] The discharging control unit includes a sample and hold circuit, the input end of the sample and hold circuit is selectively connected with the capacitor charging and discharging unit, and the output end of the sample and hold circuit is connected with the voltage stabilizing output unit.

[0039] The sample and hold circuit includes an input follower component U1, a sampling switch Q1, a holding capacitor C2, a resistor R3 and an output follower component U2 connected in sequence.

[0040] Among them, the input end of the input follower component U1 is selectively connected with the capacitor charging and discharging unit, the output end of the input follower component U1 is connected with the input end of the sampling switch Q1, the control end of the sampling switch Q1 is connected with the first square wave control signal, one end of the holding capacitor C2 is connected with the output end of the sampling switch Q1, one end of the holding capacitor C2 is also connected with the input end of the output follower component U2 through the resistor R3, the other end of the holding capacitor C2 is grounded, and the output end of the output follower component U2 is connected with the voltage stabilizing output unit.

[0041] The voltage stabilizing output unit comprises a voltage stabilizing isolating switch Q2, wherein an input end of the voltage stabilizing isolating switch Q2 is connected with an output end of the discharge control unit, an output end of the voltage stabilizing isolating switch Q2 is connected with the to-be-tested resistor RL, and a control end of the voltage stabilizing isolating switch Q2 is connected with the second square wave control signal.

[0042] Specifically, before the nonlinear resistor is tested, the charging and discharging switching circuit K1 is first adjusted, so that the external power supply can be connected with the charging and discharging capacitor C1 to charge the charging and discharging capacitor C1. It can be understood that the resistor R1 can be used to adjust the charging efficiency of the charging and discharging capacitor C1. After the charging and discharging capacitor C1 reaches the charging requirement, the charging and discharging switching circuit K1 is adjusted to disconnect the external power supply from the charging and discharging capacitor C1. When the nonlinear resistor is tested, the charging and discharging switching circuit K1 is adjusted to connect the charging and discharging capacitor C1 with the discharge control unit. It can be understood that the resistor R2 can adjust the discharging speed of C1.

[0043] The discharge control unit can be a sample and hold circuit, which samples the discharging voltage and holds the sampling signal to realize the discharging voltage with ladder characteristics, wherein the duration of each ladder is affected by the frequency and duty cycle of the first square wave signal. In a feasible example, the frequency of the first square wave control signal can be set to 1 Hz and the duty cycle can be set to 20% to realize the discharging voltage with relatively stable and long enough holding time of the ladder characteristics.

[0044] The voltage stabilizing output unit mainly realizes the voltage stabilization of the discharging voltage of each ladder by the voltage stabilizing isolating switch Q2, which realizes the interception of the voltage signal of the stable part of each ladder by the control of the second square wave control signal. Preferably, the frequency of the second square wave control signal can be the same as that of the first square wave control signal to ensure the collection of the discharging voltage of each ladder. The length of the voltage collection is affected by the duty cycle of the second square wave signal, which is generally set to be above 50%.

[0045] Referring to Figure 3 , Figure 3 The effect comparison diagram of the discharging voltage after the discharge control unit and the voltage stabilizing output unit shows that the resistor measurement module of the embodiment can convert the exponentially decreasing capacitor discharging voltage into the ladder-shaped decreasing capacitor discharging voltage to improve the synchronization time redundancy of the voltage sampling and current sampling, thereby increasing the accuracy of the nonlinear resistor test.

[0046] Further, referring to Figure 1 , the analysis module comprises a resistance analysis unit, an analog-to-digital conversion unit, a voltage acquisition unit and a current acquisition unit. The resistance analysis unit is connected with the analog-to-digital conversion unit, the analog-to-digital conversion unit is connected with the voltage acquisition unit and the current acquisition unit respectively, and the voltage acquisition unit and the current acquisition unit are connected with the to-be-tested resistor.

[0047] The analysis module further comprises a state switching unit connected with the resistance measurement module, for controlling the capacitor charging and discharging unit to charge or discharge. In a specific example, the analysis module can be connected with the charging and discharging switching circuit K1 through an MCU single-chip microcomputer, to realize control of the switching state of the charging and discharging switching circuit K1, and further control the capacitor charging and discharging unit to charge, discharge or standby.

[0048] It can be understood that the voltage acquisition unit and the current acquisition unit are respectively used to measure the voltage of the resistance to be measured and the current flowing through the resistance to be measured. Through the analysis module, the voltage and the current of the resistance to be measured RL acquired can be calculated, and the resistance characteristic of the non-linear resistance at each voltage stage can be obtained. In cooperation with the discharge control of the discharge control unit, the voltage signal can be continuously acquired from high to low without frequent adjustment of the voltage level.

[0049] It should be understood that various parts of the present application can be realized by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0050] In another embodiment, the present application further provides a non-linear resistance tester, which is composed of the non-linear resistance testing system described in the above embodiments.

[0051] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0052] The above is only part of the embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields within the technical concept of the present application, and the contents of the present application and the attached drawings are included in the patent protection scope of the present application.

Claims

1. A nonlinear resistance testing system, characterized in that, It includes a resistance measurement module and an analysis module that are interconnected. The resistance measurement module includes a capacitor charging and discharging unit, a discharge control unit selectively connected to the capacitor charging and discharging unit, and a voltage regulated output unit connected to the discharge control unit. The capacitor charging and discharging unit is also selectively connected to the charging power supply, the voltage regulation output unit is also connected to the resistor under test, and the analysis module is also connected to the resistor under test. The capacitor charging and discharging unit includes a charging and discharging capacitor and a charging and discharging switching circuit connected in sequence. The charging and discharging capacitor is selectively connected to the power supply and the discharge control unit respectively through the charging and discharging switching circuit. The charge / discharge switching circuit is used to control the charging or discharging of the charging / discharging capacitor.

2. The nonlinear resistance testing system as described in claim 1, characterized in that, The discharge control unit includes a sample-and-hold circuit, the input of which is selectively connected to the capacitor charging and discharging unit, and the output of which is connected to the voltage regulator output unit.

3. The nonlinear resistance testing system as described in claim 2, characterized in that, The sample-and-hold circuit includes an input follower component, a sampling switch, a holding capacitor, a resistor, and an output follower component connected in sequence. The input terminal of the input follower component is selectively connected to the capacitor charging and discharging unit, the output terminal of the input follower component is connected to the input terminal of the sampling switch, the control terminal of the sampling switch is connected to a first square wave control signal, the output terminal of the sampling switch is connected to one end of the holding capacitor, one end of the holding capacitor is also connected to the input terminal of the output follower component through the resistor, the other end of the holding capacitor is grounded, and the output terminal of the output follower component is connected to the voltage regulator output unit.

4. The nonlinear resistance testing system as described in claim 3, characterized in that, The voltage-regulated output unit includes a voltage-regulated isolating switch, wherein the input terminal of the voltage-regulated isolating switch is connected to the output terminal of the discharge control unit, the output terminal of the voltage-regulated isolating switch is connected to the resistor under test, and the control terminal of the voltage-regulated isolating switch is connected to a second square wave control signal.

5. The nonlinear resistance testing system as described in claim 1, characterized in that, The analysis module includes a resistance analysis unit, an analog-to-digital conversion unit, a voltage acquisition unit, and a current acquisition unit; The resistance analysis unit is connected to the analog-to-digital conversion unit, which is connected to the voltage acquisition unit and the current acquisition unit, respectively. Both the voltage acquisition unit and the current acquisition unit are connected to the resistor under test.

6. The nonlinear resistance testing system as described in claim 5, characterized in that, The analysis module also includes a state switching unit, which is connected to the resistance measurement module.

7. A nonlinear resistance tester, wherein the nonlinear resistance tester comprises the nonlinear resistance testing system as described in any one of claims 1-6.

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