Alternating current parameter tester

Abstract

The utility model relates to measuring alternating current parameter technical field discloses alternating current parameter tester, include: the signal acquisition module for carrying out the collection to the product parameter signal of measurement, prevent the short circuit protection module of instrument appearance short circuit or reverse connection and influence test process, signal acquisition module includes the voltage division unit, filter unit, AD conversion unit that connect gradually, short circuit protection module includes signal amplification unit, signal isolation unit, on-off control unit that connect gradually. The utility model has the advantages of high collection precision, fast speed, good stability by precision resistance voltage division, then filtering processing, and the analog signal is converted into digital signal and handles, can use in high temperature and normal temperature environment, newly added short circuit protection module that can test the protection of product, no matter what kind of circuit problem appears in the process of testing the product, can realize automatic protection, will not influence the alternating current parameter measurement of test instrument to product.

Description

Technical Field

[0001] This utility model relates to the field of AC parameter measurement technology, specifically an AC parameter tester. Background Technology

[0002] Alternating current (AC) is a type of electric current that varies with time. Its parameters include frequency, period, amplitude (maximum and effective values), phase, and power. AC is generally classified into sinusoidal AC and non-sinusoidal AC. Sinusoidal AC current changes with time according to a sinusoidal law, while non-sinusoidal AC includes more variations. Measurement of AC parameters includes frequency and period measurement, amplitude measurement, phase measurement, and power measurement.

[0003] A search revealed a patent application with application number CN202111107457.9 that discloses a method for testing aviation AC power parameters. The specific steps are as follows: S1, a transformer converts the high-voltage AC signal to be tested into a voltage signal u1, and a current sensor converts the current signal to be tested into a current signal i1; S2, signal conditioning and amplification yield u2 and i2; S3, zero-crossing detection; S4, signal frequency multiplication to obtain a sampling clock; S5, simultaneous sampling of voltage and current; S6, transmission of sampled data to the subsequent CPU for calculation to obtain parameter results. By using a digital frequency multiplier generated by the FPGA's internal digital circuitry, the method avoids the shortcomings of poor stability, low consistency, and low maximum output frequency associated with analog phase-locked loop frequency multiplication. This frequency multiplier generates a square wave signal with a frequency N times that of the power supply under test, and this frequency can change with the input voltage frequency, achieving real-time tracking and avoiding spectral leakage. It can be applied to the 400Hz aviation power supply testing field.

[0004] In traditional AC parameter testing, the testing instruments only have testing functions and no product protection functions. That is, the product needs to be guaranteed to be free of short circuits or reverse soldering before testing. If such situations exist, the module itself may be damaged. Therefore, we need to propose an AC parameter tester. Summary of the Invention

[0005] The purpose of this invention is to provide an AC power parameter tester that uses precision resistor voltage division, filtering, and conversion of analog signals into digital signals for processing. It features high acquisition accuracy, fast speed, and good stability, and can be used in both high-temperature and normal-temperature environments. A short-circuit protection module has been added to protect the product during testing. Regardless of the circuit problem encountered during testing, automatic protection is achieved without affecting the instrument's measurement of the product's AC power parameters, thus solving the problems mentioned in the background section.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an AC parameter tester, comprising:

[0007] A signal acquisition module used to collect parameter signals of the product under test;

[0008] A short-circuit protection module to prevent short circuits or reverse connections in the instrument from affecting the testing process;

[0009] The signal acquisition module includes a voltage divider unit, a filter unit, and an analog-to-digital converter unit connected in sequence, and the short-circuit protection module includes a signal amplification unit, a signal isolation unit, and a switching control unit connected in sequence.

[0010] Preferably, the voltage divider unit includes a terminal block J10, and resistors R16, R17, R18, R19, and R20 are connected in series between pins 1 and 3 of the terminal block J10.

[0011] Preferably, the filtering unit includes a diode D6 connected to the input voltage, a capacitor C11 connected in parallel with the diode D6, and a capacitor C10 and a capacitor C12 connected in series. A resistor R14 is connected between one end of the diode D6 and one end of the resistor R20, and a resistor R22 is connected between the other end of the diode D6 and the other end of the resistor R20. Resistors R2 and R24 are respectively connected to the terminals of resistors R20 and R22.

[0012] Preferably, the analog-to-digital conversion unit includes a terminal block J12, an optocoupler U9, a current sensor L1A, a MOSFET Q1, and a relay RLY1. The resistor R2 is connected to the first terminal of the relay RLY1. A diode D8 is connected between the first and second ends of the coil of the relay RLY1. A series-connected light-emitting diode D12 and a resistor R74 are connected in parallel across the two ends of the diode D8. A resistor R27, a resistor R28, a diode D9, and a diode D10 are connected in parallel between the first terminal of the relay RLY1 and the normally open contact.

[0013] Preferably, the normally open contact of the relay RLY1 is connected to the first terminal of the current sensor L1A. A diode D11 and a series resistors R32 and R35 are connected in parallel between the first and second terminals of the current sensor L1A. The second terminal of the coil of the relay RLY1 is connected to the drain of the MOSFET Q1. A resistor R45 is connected between the gate and source of the MOSFET Q1. A resistor R33 is connected between the control signal terminal of the terminal block J12 and the gate of the MOSFET Q1. The output terminal of the optocoupler U9 is connected to the control signal terminal of the terminal block J12.

[0014] Preferably, the signal amplification unit includes amplifier U14A, amplifier U14B, and amplifier U15A. A resistor R83 is connected between the non-inverting input terminal of amplifier U14A and the output terminal of amplifier U15A. A resistor R91 is connected between the inverting input terminal of amplifier U14A and the output terminal of amplifier U14B. A diode D15 is connected to the output terminal of amplifier U14A. One output terminal of diode D15 is connected to a resistor R80, and the other output terminal of diode D15 is connected to a resistor R77 between the non-inverting input terminal of amplifier U14A.

[0015] Preferably, the signal isolation unit includes an optocoupler U1, with a resistor R1 connected between the input terminal of the optocoupler U1 and the output terminal of the amplifier U14A, and a resistor R86 connected to the output terminal of the optocoupler U1.

[0016] Preferably, the on / off control unit includes a relay RLY2 and a transistor Q4. A diode D17, a light-emitting diode D16, and a resistor R84 are connected in parallel between the first and second ends of the coil of the relay RLY2. The second end of the coil of the relay RLY2 is connected to the collector of the transistor Q4. A resistor R87 is connected between the base and emitter of the transistor Q4. A resistor R86 is connected to the base of the transistor Q4.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] 1. This utility model uses precision resistor voltage division, then filtering, and converts analog signals into digital signals for processing. It has the advantages of high acquisition accuracy, fast speed, and good stability, and can be used in both high temperature and normal temperature environments.

[0019] 2. This utility model adds a short-circuit protection module that can protect the product during testing. No matter what kind of circuit problem occurs during the testing process, it can automatically protect the product without affecting the test instrument's measurement of the product's AC parameters. Attached Figure Description

[0020] Fig. 1 This is a circuit diagram of the signal acquisition module of this utility model;

[0021] Fig. 2 This is the circuit diagram of the short-circuit protection module of this utility model. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see Figs. 1-2 This utility model provides a technical solution: an AC power parameter tester, comprising:

[0024] This signal acquisition module is used to collect parameter signals of the product under test. The signal is divided and filtered by a precision resistor and then enters a 24-bit ADC to convert the analog signal into a digital signal. The Fourier algorithm is used to analyze the signal and obtain the values ​​of each parameter. It has high acquisition accuracy, fast speed and good stability, and can be used in both high temperature and normal temperature environments.

[0025] Signal acquisition module: Measures AC electrical parameters and analyzes AC signal characteristics.

[0026] A short-circuit protection module to prevent short circuits or reverse connections in the instrument from affecting the testing process;

[0027] The short-circuit protection module has a short-circuit protection function, so no matter what kind of circuit problem occurs in the tested product, it will not affect the measurement of the instrument itself, thus achieving automatic protection.

[0028] The signal acquisition module includes a voltage divider unit, a filter unit, and an analog-to-digital converter unit connected in sequence.

[0029] The voltage divider unit includes a terminal block J10. Resistors R16, R17, R18, R19, and R20 are connected in series between pins 1 and 3 of the terminal block J10. Resistors R16, R17, R18, R19, and R20 serve as voltage dividers.

[0030] The filtering unit includes a diode D6 connected to the input voltage. A capacitor C11 and two capacitors C10 and C12 are connected in series on the diode D6. A resistor R14 is connected between one end of the diode D6 and one end of the resistor R20. A resistor R22 is connected between the other end of the diode D6 and the other end of the resistor R20. Resistors R2 and R24 are connected to the terminals of resistors R20 and R22, respectively.

[0031] Capacitors C10, C11, and C12 are used for filtering and energy storage, diode D6 is used to protect the circuit from reverse voltage damage, and resistor R24 ​​is used for voltage division and current limiting.

[0032] The analog-to-digital conversion unit includes a terminal block J12, an optocoupler U9, a current sensor L1A, a MOSFET Q1, and a relay RLY1. A resistor R2 is connected to the first terminal of the relay RLY1. A diode D8 is connected between the first and second ends of the coil of the relay RLY1. A series-connected light-emitting diode D12 and a resistor R74 are connected in parallel across the two ends of the diode D8. A resistor R27, a resistor R28, a diode D9, and a diode D10 are connected in parallel between the first terminal of the relay RLY1 and the normally open contact.

[0033] The normally open contact of the relay RLY1 is connected to the first terminal of the current sensor L1A. A diode D11 and a series resistors R32 and R35 are connected in parallel between the first and second terminals of the current sensor L1A. The second terminal of the coil of the relay RLY1 is connected to the drain of the MOSFET Q1. A resistor R45 is connected between the gate and source of the MOSFET Q1. A resistor R33 is connected between the control signal terminal of the terminal block J12 and the gate of the MOSFET Q1. The output terminal of the optocoupler U9 is connected to the control signal terminal of the terminal block J12.

[0034] Resistors R27 and R28 are used for voltage division and current limiting, diodes D9 and D10 are used to protect the circuit from reverse voltage damage, and resistors R26 and R29 are used for voltage division and current limiting.

[0035] Terminal block J12 is used to connect to an external power supply. Diode D12 is used to protect the circuit from reverse voltage damage. Pin 2 of optocoupler U9 is connected to resistor R38, and switch SW_I is connected to resistor R38 to control the circuit's on / off state. MOSFET Q1 is used for signal amplification and switch control, and current sensor L1A is used to measure current.

[0036] The short-circuit protection module includes a signal amplification unit, a signal isolation unit, and a switching control unit connected in sequence.

[0037] The signal amplification unit includes amplifiers U14A, U14B, and U15A. A resistor R83 is connected between the non-inverting input terminal of amplifier U14A and the output terminal of amplifier U15A. A resistor R91 is connected between the inverting input terminal of amplifier U14A and the output terminal of amplifier U14B. A diode D15 is connected to the output terminal of amplifier U14A. One output terminal of diode D15 is connected to a resistor R80, and the other output terminal of diode D15 is connected to a resistor R77 between the non-inverting input terminal of amplifier U14A.

[0038] A resistor R81, an inductor L1, and a resistor R78 are connected between pins 2 and 3 of amplifier U15A. Resistors R79 and R82 are connected in parallel across the two ends of inductor L1. One end of resistor R79 is connected to a grounded resistor R75. Resistor R85 is connected between pins 1 and 2 of amplifier U15A.

[0039] Resistors R89 and R90 are connected sequentially to pin 5 of amplifier U14B, and capacitor C28 is also connected to pin 5 of amplifier U14B. Capacitor C29 is connected to the terminals of resistors R89 and R90. Both capacitors C28 and C29 are grounded. Pins 6 and 7 of amplifier U14B are connected.

[0040] The signal isolation unit includes an optocoupler U1. A resistor R1 is connected between the input terminal of the optocoupler U1 and the output terminal of the amplifier U14A, and a resistor R86 is connected to the output terminal of the optocoupler U1. Through the design of the signal isolation unit, external factors will not affect the instrument itself, and all interfaces are replaceable and compatible with various standard protocols.

[0041] The on / off control unit includes a relay RLY2 and a transistor Q4. A diode D17, a light-emitting diode D16, and a resistor R84 are connected in parallel between the first and second ends of the coil of the relay RLY2. The second end of the coil of the relay RLY2 is connected to the collector of the transistor Q4. A resistor R87 is connected between the base and emitter of the transistor Q4. A resistor R86 is connected to the base of the transistor Q4.

[0042] Relay RLY2 is used to control the on / off state of the circuit, diodes D16 and D17 are used to protect the circuit and prevent reverse current, and resistor R84 is used for current limiting and voltage division.

[0043] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An AC parameter tester, characterized in that, include: A signal acquisition module used to collect parameter signals of the product under test; A short-circuit protection module is provided to prevent short circuits or reverse connections in the instrument from affecting the testing process; the signal acquisition module includes a voltage divider unit, a filter unit, and an analog-to-digital converter unit connected in sequence, and the short-circuit protection module includes a signal amplification unit, a signal isolation unit, and a switching control unit connected in sequence.

2. The AC parameter tester according to claim 1, characterized in that: The voltage divider unit includes a terminal block J10, and resistors R16, R17, R18, R19, and R20 are connected in series between pins 1 and 3 of the terminal block J10.

3. The AC parameter tester according to claim 2, characterized in that: The filtering unit includes a diode D6 connected to the input voltage. A capacitor C11 and two capacitors C10 and C12 are connected in series on the diode D6. A resistor R14 is connected between one end of the diode D6 and one end of the resistor R20. A resistor R22 is connected between the other end of the diode D6 and the other end of the resistor R20. Resistors R2 and R24 are connected to the terminals of resistors R20 and R22, respectively.

4. The AC parameter tester according to claim 3, characterized in that: The analog-to-digital conversion unit includes a terminal block J12, an optocoupler U9, a current sensor L1A, a MOSFET Q1, and a relay RLY1. A resistor R2 is connected to the first terminal of the relay RLY1. A diode D8 is connected between the first and second ends of the coil of the relay RLY1. A series-connected light-emitting diode D12 and a resistor R74 are connected in parallel across the two ends of the diode D8. A resistor R27, a resistor R28, a diode D9, and a diode D10 are connected in parallel between the first terminal of the relay RLY1 and the normally open contact.

5. The AC parameter tester according to claim 4, characterized in that: The normally open contact of the relay RLY1 is connected to the first terminal of the current sensor L1A. A diode D11 and a series resistors R32 and R35 are connected in parallel between the first and second terminals of the current sensor L1A. The second terminal of the coil of the relay RLY1 is connected to the drain of the MOSFET Q1. A resistor R45 is connected between the gate and source of the MOSFET Q1. A resistor R33 is connected between the control signal terminal of the terminal block J12 and the gate of the MOSFET Q1. The output terminal of the optocoupler U9 is connected to the control signal terminal of the terminal block J12.

6. The AC parameter tester according to claim 5, characterized in that: The signal amplification unit includes amplifiers U14A, U14B, and U15A. A resistor R83 is connected between the non-inverting input terminal of amplifier U14A and the output terminal of amplifier U15A. A resistor R91 is connected between the inverting input terminal of amplifier U14A and the output terminal of amplifier U14B. A diode D15 is connected to the output terminal of amplifier U14A. One output terminal of diode D15 is connected to a resistor R80, and the other output terminal of diode D15 is connected to a resistor R77 between the non-inverting input terminal of amplifier U14A.

7. The AC parameter tester according to claim 6, characterized in that: The signal isolation unit includes an optocoupler U1, with a resistor R1 connected between the input terminal of the optocoupler U1 and the output terminal of the amplifier U14A, and a resistor R86 connected to the output terminal of the optocoupler U1.

8. The AC parameter tester according to claim 7, characterized in that: The on / off control unit includes a relay RLY2 and a transistor Q4. A diode D17, a light-emitting diode D16, and a resistor R84 are connected in parallel between the first and second ends of the coil of the relay RLY2. The second end of the coil of the relay RLY2 is connected to the collector of the transistor Q4. A resistor R87 is connected between the base and emitter of the transistor Q4. A resistor R86 is connected to the base of the transistor Q4.

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