A three-phase motor phase sequence detection device and method based on signal amplification

Abstract

The present invention provides a three-phase motor phase sequence detection device and method based on signal amplification, including a power module, a signal acquisition and processing module and an indication module; the power module is respectively connected to the signal acquisition and processing module and the indication module as a power supply; the signal acquisition and processing module is used to collect and process the signal sent by the detected device, and the signal acquisition and processing module is connected to the indication module; the signal acquisition and processing module includes a signal acquisition unit, a signal amplification unit, a signal adjustment unit, a signal conversion unit and a signal integration unit; the output end of the detected device is connected to the signal acquisition unit, and the signal acquisition unit is connected to the signal amplification unit, the signal adjustment unit, the signal conversion unit and the signal integration unit in turn, and the output end of the signal integration unit is connected to the indication module. When using the device and method provided by the present invention to detect, the step of dry-testing the motor can be avoided, thereby enhancing the safety of personnel and equipment.

Description

Technical Field

[0001] The invention relates to the technical field of instruments and meters, and in particular to a three-phase motor phase sequence detection device and method based on signal amplification. Background Art

[0002] Three-phase motors are widely used in industrial production. Three-phase motors are divided into high-voltage motors and low-voltage motors according to voltage levels. When a motor is newly installed, replaced, or the winding is rewound and reinstalled, incorrect wiring will cause the motor to reverse. The consequence is that the reverse rotation will increase the working time and affect the work progress; in serious cases, it may cause equipment damage and cause economic losses.

[0003] The current method is to connect the lines and test the motor in an empty state. The specific operation is to power on the motor to test the direction before it is in place. This method is time-consuming and labor-intensive, and some occasions do not have the conditions for an empty test, so it can only be tested with a load. Some loads do not allow reversal. Once the wiring is wrong, it will damage the equipment, causing economic losses, and in serious cases, personal accidents. Summary of the invention

[0004] In view of the above technical problems existing in the prior art, the present invention proposes a three-phase motor phase sequence detection device and method based on signal amplification, which has a reasonable design, overcomes the shortcomings of the prior art, and has good effects.

[0005] In order to achieve the invention objective 1, the present invention adopts the following technical solution:

[0006] A three-phase motor phase sequence detection device based on signal amplification includes a power supply module, a signal acquisition and processing module and an indication module; the power supply module is respectively connected to the signal acquisition and processing module and the indication module as a power supply; the signal acquisition and processing module is used to collect and process the signal sent by the detected device, and the signal acquisition and processing module is connected to the indication module;

[0007] Among them, the signal acquisition and processing module includes:

[0008] A signal acquisition unit, used for acquiring signals from the detected device;

[0009] A signal amplifying unit, for amplifying the collected signal;

[0010] A signal adjustment unit, used for adjusting the amplification factor of the signal;

[0011] A signal conversion unit, used for converting the waveform of the amplified signal;

[0012] A signal integration unit, used for integrating the transformed signal waveform;

[0013] The output end of the detected device is connected to the signal acquisition unit, the signal acquisition unit is connected to the signal amplification unit, the signal adjustment unit, the signal conversion unit and the signal integration unit in sequence, and the output end of the signal integration unit is connected to the indication module.

[0014] Preferably, the power module provides working power for the circuit and adopts a bipolar DC power supply composed of two 9V alkaline batteries.

[0015] Preferably, the signal acquisition unit includes a first signal acquisition unit, a second signal acquisition unit and a third signal acquisition unit, and the first, second and third signal acquisition units each include a shielded wire with an alligator clip, one end of the alligator clip is respectively connected to the terminals U, V, and W of the three-phase motor, and the other end is connected to the input end of the signal amplification unit.

[0016] Preferably, the signal amplification unit includes a first signal amplification unit, a second signal amplification unit and a third signal amplification unit, and the first, second and third signal amplification units are all two-stage amplification circuits composed of operational amplifiers and resistors; the input ends of the first, second and third signal amplification units are correspondingly connected to the output end of the signal acquisition unit, and the indication module is used to indicate the above-mentioned processed signals.

[0017] Preferably, the signal adjustment unit includes a first signal adjustment unit, a second signal adjustment unit and a third signal adjustment unit. The first, second and third signal adjustment units are all voltage gain adjustable amplifier circuits composed of operational amplifiers, resistors and potentiometers. The input ends of the first, second and third signal adjustment units are correspondingly connected to the output end of the signal amplification unit, the output ends of the first and third signal adjustment units are connected to the input end of the signal conversion unit, and the output end of the second signal adjustment unit is connected to the input end of the signal integration unit.

[0018] Preferably, the signal conversion unit includes a first signal conversion unit and a second signal conversion unit, and the first and second signal conversion units are both integration circuits and differentiation circuits composed of operational amplifiers, resistors and capacitors; wherein the input end of the first signal conversion unit is connected to the output end of the first signal adjustment unit, the input end of the second signal conversion unit is connected to the output end of the third signal adjustment unit, and the output ends of the first and second signal conversion units are connected to the signal integration unit.

[0019] Preferably, the signal integration unit includes a first signal integration unit and a second signal integration unit, and the first and second signal integration units are both addition circuits composed of operational amplifiers and resistors; wherein the input ends of the first and second signal integration units are both connected to the output ends of the first signal conversion unit, the second signal conversion unit and the second signal adjustment unit, and the output ends of the first and second signal integration units are both connected to the indication module.

[0020] Preferably, the indication module includes a positive sequence indication unit and a negative sequence indication unit, the positive sequence indication unit is composed of a positive sequence indicator light LED1 and a resistor, and the negative sequence indication unit is composed of a negative sequence indicator light LED2 and a resistor; the positive sequence indication unit is connected to the output end of the first signal integration unit, and the negative sequence indication unit is connected to the output end of the second signal integration unit.

[0021] In order to achieve the second object of the invention, the present invention adopts the following technical solution:

[0022] A three-phase motor phase sequence detection method based on signal amplification comprises the following steps:

[0023] Step 1: Turn on the power of the device and connect the three shielded wires with alligator clips of the signal acquisition unit to the three terminals U, V, and W of the three-phase motor respectively;

[0024] Step 2: Manually rotate the rotor of the three-phase motor in a given direction and observe the indicator module;

[0025] Step 3: Adjust the signal conditioning unit and observe the indicator module;

[0026] Step 4: If the brightness of the positive-sequence indicator LED1 in the indication module is significantly greater than that of the negative-sequence indicator LED2, the terminals U, V, and W of the three-phase motor are connected to the positive-sequence power supply; if the brightness of the negative-sequence indicator LED2 is significantly greater than that of the positive-sequence indicator LED1, the terminals U, V, and W of the three-phase motor are connected to the negative-sequence power supply.

[0027] Preferably, step 3 includes the following sub-steps:

[0028] Step 31: The three-phase signals a, b, and c output by the signal acquisition unit are positive sequence or negative sequence, and their phasor relationship is u∠+120°, u∠0°, u∠-120° or u∠-120°, u∠0°, and u∠+120°. After two-stage amplification by the signal amplification unit, three groups of sine waves A, B, and C are obtained, and their phasor relationship is U∠+120°, U∠0°, U∠-120° or U∠-120°, U∠0°, and U∠+120°. Then, the amplification factor is adjusted by the signal adjustment unit, and the sine wave signal output by the first signal adjustment unit is passed through the differential circuit in the first signal conversion unit to shift the phase by 90° to obtain a sine wave A. 1 , its phasor is expressed as U∠+30° or U∠-210°. The sine wave signal output by the third signal conditioning unit passes through the integration circuit in the second signal conversion unit, so that the phase is shifted forward by 90° to obtain the sine wave C 1 , whose phasor is expressed as U∠-30° or U∠+210°, passes through the adding circuit in the first signal integration unit, so that A 1 , B, C 1The sine wave L1 is obtained by adding them together, and the sine wave L1 lights up the positive sequence indicator LED1;

[0029] Step 32: The sine wave signal output by the first signal conditioning unit is passed through the integration circuit in the first signal conversion unit to shift the phase forward by 90° to obtain a sine wave A. 2 , its phasor is expressed as U∠+210° or U∠-30°. The sine wave signal output by the third signal conditioning unit passes through the differential circuit in the second signal conversion unit, so that the phase is shifted 90° to obtain the sine wave C 2 , whose phasor is expressed as U∠-210° or U∠+30°, passes through the adding circuit in the first signal integration unit, so that A 2 , B, C 2 The addition results in a sine wave L2, which lights up the negative sequence indicator LED2;

[0030] Step 33: Observe the brightness of the positive sequence indicator LED1 and the negative sequence indicator LED2.

[0031] Beneficial technical effects brought by the present invention:

[0032] First, the device uses electronic components to make a circuit board, which is powered by a battery. It is small in size, simple in structure, and easy to carry. Second, when testing, you only need to clamp three sets of crocodile clips on the motor terminals, turn the motor in a given direction, and observe the brightness of the positive and negative sequence indicator lights to determine the power phase sequence that should be connected when the motor rotates in a given direction. The operation is simple and fast, and the detection is accurate. Third, using this device for testing can avoid the step of dry testing the motor, thereby enhancing the safety of personnel and equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the present invention;

[0034] Figure 2 The electrical schematic diagram proposed for the present invention; DETAILED DESCRIPTION

[0035] The following is a further description of the specific implementation of the present invention in conjunction with the accompanying drawings and specific embodiments:

[0036] like Figure 1-2 As shown, a three-phase motor phase sequence detection device based on signal amplification includes a power supply module, a signal acquisition and processing module and an indication module;

[0037] The power module is used to provide working power for the circuit; the power module includes a bipolar DC power supply consisting of two 9V alkaline batteries, which are connected to the signal acquisition and processing module and the indication module respectively.

[0038] The signal acquisition and processing module is used to acquire and process the signal sent by the detected device; the signal acquisition and processing module includes: a signal acquisition unit, a signal amplification unit, a signal adjustment unit, a signal conversion unit and a signal integration unit.

[0039] Specifically, the signal acquisition unit is used to collect the signal of the detected device; the signal acquisition unit includes a first signal acquisition unit, a second signal acquisition unit and a third signal acquisition unit, each of which includes a shielded wire with an alligator clip, one end of the alligator clip is respectively connected to the terminals U, V, and W of the three-phase motor, and the other end is connected to the input end of the signal amplification unit. The shielded wire can reduce the interference of the external environment on weak signals.

[0040] Specifically, the signal amplification unit is used to amplify the above-mentioned collected signal; the signal amplification unit includes a first signal amplification unit, a second signal amplification unit and a third signal amplification unit; the first signal amplification unit includes a two-stage amplification circuit composed of a first operational amplifier LM324 and resistors R1, R2, R3, R4, R5 and R6, and the first operational amplifier LM324 is represented by U1; the second signal amplification unit includes a second operational amplifier LM324 and resistors R10, R11, R12, R13, R14, and R15 The second operational amplifier LM324 is represented by U2; the third signal amplifying unit includes a two-stage amplifying circuit composed of the third operational amplifier LM324 and resistors R19, R20, R21, R22, R23 and R24, and the third operational amplifier LM324 is represented by U3; the input ends of the first signal amplifying unit, the second signal amplifying unit and the third signal amplifying unit are respectively connected to the output ends of the first signal acquisition unit, the second signal acquisition unit and the third signal acquisition unit, and their output ends are connected to the input end of the signal adjustment unit.

[0041] Specifically, the signal adjustment unit is used to adjust the amplification factor of the signal; the signal adjustment unit includes a first signal adjustment unit, a second signal adjustment unit and a third signal adjustment unit; the first signal adjustment unit includes an amplifier circuit with adjustable voltage gain composed of a first operational amplifier LM324 and a potentiometer R8, a resistor R7 and a resistor R9, the second signal adjustment unit includes an amplifier circuit with adjustable voltage gain composed of a second operational amplifier LM324 and a potentiometer R17, resistors R16 and R18, and the third signal adjustment unit includes an amplifier circuit with adjustable voltage gain composed of a third operational amplifier LM324 and a potentiometer R26, a resistor R25 and a resistor R27; the input ends of the first signal adjustment unit, the second signal adjustment unit and the third signal adjustment unit are respectively connected to the output ends of the first signal amplification unit, the second signal amplification unit and the third signal amplification unit, the output ends of the first signal adjustment unit and the third signal adjustment unit are connected to the input end of the signal conversion unit, and the output end of the second signal adjustment unit is connected to the input end of the signal integration unit.

[0042] Specifically, the signal conversion unit is used to convert the above-mentioned amplified signal waveform; the signal conversion unit includes a first signal conversion unit and a second signal conversion unit; the first signal conversion unit includes an integration circuit composed of a fourth operational amplifier LM324 and a capacitor C1, a resistor R28, a resistor R29 and a resistor R30, and a differential circuit composed of a fourth operational amplifier LM324 and a capacitor C2, a resistor R31, a resistor R32 and a resistor R33, and the fourth operational amplifier LM324 is represented by U4; the second signal conversion unit includes an integration circuit composed of a fifth operational amplifier LM324 and a capacitor C3, a resistor R34, a resistor R35 and a resistor R36, and a differential circuit composed of a fifth operational amplifier LM324 and a capacitor C4, a resistor R37, a resistor R38 and a resistor R39, and the fifth operational amplifier LM324 is represented by U5; the input ends of the first signal conversion unit and the second signal conversion unit are respectively connected to the output ends of the first signal adjustment unit and the third signal adjustment unit, and their output ends are connected to the input end of the signal integration unit.

[0043] Specifically, the signal integration unit is used to integrate the above-mentioned transformed signal waveform; the signal integration unit includes a first signal integration unit and a second signal integration unit; the first signal integration unit includes an adding circuit composed of a fourth operational amplifier LM324 and resistors R40, R41, R42, R43 and R44, and the second signal integration unit includes an adding circuit composed of a fifth operational amplifier LM324 and resistors R45, R46, R47, R48 and R49; the input ends of the first signal integration unit and the second signal integration unit are connected to the output ends of the first signal conversion unit, the second signal adjustment unit and the second signal conversion unit, and their output ends are connected to the indication module.

[0044] An indication module is used to indicate the above-mentioned processed signal; the indication module includes a positive sequence indication unit and a negative sequence indication unit, the positive sequence indication unit includes a positive sequence indicator light LED1 and a resistor R50, the negative sequence indication unit includes a negative sequence indicator light LED2 and a resistor R51, the input end of the positive sequence indication unit is connected to the output end of the first signal integration unit, and the input end of the negative sequence indication unit is connected to the output end of the second signal integration unit.

[0045] The working principle of the phase sequence detection device is:

[0046] When a three-phase motor is manually cranked, due to the influence of the residual magnetism in the iron core, the winding coil will produce three sets of sinusoidal waves with a phase difference of 120° (positive sequence or negative sequence, whose phase relationship is u∠+120°, u∠0°, u∠-120° or u∠-120°, u∠0°, u∠+120°). The phase sequence is the same as the phase sequence of the three-phase power supply that makes the motor rotate in the same direction.

[0047] During the detection, the three terminals U, V, and W of the three-phase motor are connected to the three shielded wires as signal input. The three-phase motor is manually rotated in a given direction. Assuming that the phase relationship of the positive sequence signals a, b, and c generated by the winding coil is u∠+120°, u∠0°, and u∠-120°, they are respectively amplified in two stages by the first operational amplifier LM324, the second operational amplifier LM324, and the third operational amplifier LM324. Three groups of sine waves A, B, and C with greatly increased amplitudes (Am, Bm, Cm) and unchanged phase sequence will be obtained, and their phase relationship is U∠+120°, U∠0°, and U∠-120°. Then, the amplification factor is adjusted by the signal adjustment unit. Reasonable selection of the values ​​of R28, C1, R31, C2, R34, C3, R37, and C4 ensures that the amplitude of the signal waveform remains basically unchanged after transformation. The sine wave signal output by the first signal conditioning unit passes through the differential circuit in the first signal conversion unit, so that the phase is shifted 90° to obtain the sine wave A. 1(U∠+30°), the sine wave signal output by the third signal conditioning unit passes through the integration circuit in the second signal conversion unit, so that the phase is shifted forward by 90° to obtain a sine wave C 1 (U∠-30°), through the adding circuit in the first signal integration unit, A 1 , B, C 1 Adding them together, we get an amplitude of The sine wave L1 of the first signal conditioning unit lights up the positive sequence indicator LED1. Similarly, the sine wave signal output by the first signal conditioning unit passes through the integration circuit in the first signal conversion unit, so that the phase is shifted forward by 90° to obtain the sine wave A. 2 (U∠+210°), the sine wave signal output by the third signal conditioning unit passes through the differential circuit in the second signal conversion unit, so that the phase is shifted 90° to obtain a sine wave C 2 (U∠-210°), through the adding circuit in the second signal integration unit, A 2 , B, C 2 Adding them together, we get an amplitude of The sine wave L2 lights up the negative sequence indicator LED2. From L1 and L2, we can see that the positive sequence indicator LED1 is much brighter than the negative sequence indicator LED2. Therefore, to make the motor rotate in a given direction, the three-phase motor terminals U, V, and W should be connected to the positive sequence power supply.

[0048] Similarly, if the motor winding coil generates a negative sequence signal according to the given steering wheel, its phase relationship is u∠-120°, u∠0°, u∠+120°, then the amplitude of L1 becomes The amplitude of L2 becomes Light up LED1 and LED2 respectively, and the negative sequence indicator LED2 is much brighter than the positive sequence indicator LED1. In this case, if the motor is to rotate in a given direction, it is necessary to connect a negative sequence power supply.

[0049] It should be noted that the phase sequence obtained by comparing the brightness of the positive-sequence and negative-sequence indicator lights directly reflects the "phase sequence" of the three groups of signals generated by the winding coil when the motor is manually turned. Since it is the same as the phase sequence of the three-phase power supply connected to make the motor rotate in the same direction, the detected phase sequence can represent the power supply phase sequence that the motor should be connected to.

[0050] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A three-phase motor phase sequence detection method based on signal amplification, characterized in that: A three-phase motor phase sequence detection device based on signal amplification is adopted, which includes a power supply module, a signal acquisition and processing module and an indication module; the power supply module is respectively connected to the signal acquisition and processing module and the indication module as a power supply; the signal acquisition and processing module is used to collect and process the signal sent by the detected device, and the indication module is used to indicate the processed signal; Among them, the signal acquisition and processing module includes: A signal acquisition unit, used for acquiring signals from the detected device; The signal amplification unit amplifies the collected signal; A signal adjustment unit, used for adjusting the amplification factor of the signal; A signal conversion unit, used for converting the waveform of the amplified signal; A signal integration unit, used for integrating the transformed signal waveform; The output end of the three-phase motor is connected to the signal acquisition unit, the signal acquisition unit is connected to the signal amplification unit, the signal adjustment unit, the signal conversion unit and the signal integration unit in sequence, and the output end of the signal integration unit is connected to the indication module; The three-phase motor phase sequence detection method comprises the following steps: Step 1: Turn on the power of the device and connect the three shielded wires with alligator clips of the signal acquisition unit to the three terminals U, V, and W of the three-phase motor respectively; Step 2: Manually rotate the rotor of the three-phase motor in a given direction and observe the indicator module; Step 3: Adjust the signal conditioning unit and observe the indicator module; Step 4: If the brightness of the positive sequence indicator LED1 in the indication module is significantly greater than the brightness of the negative sequence indicator LED2, the terminals U, V, and W of the three-phase motor are connected to the positive sequence power supply; if the brightness of the negative sequence indicator LED2 is significantly greater than the brightness of the positive sequence indicator LED1, the terminals U, V, and W of the three-phase motor are connected to the negative sequence power supply; Step 3 includes the following sub-steps: Step 31: The three-phase signals a, b, and c output by the signal acquisition unit are positive sequence or negative sequence, and their phasor relationship is u∠+120°, u∠0°, u∠-120° or u∠-120°, u∠0°, and u∠+120°. After two-stage amplification by the signal amplification unit, three groups of sine waves A, B, and C are obtained, and their phasor relationship is U∠+120°, U∠0°, U∠-120° or U∠-120°, U∠0°, and U∠+120°. Then, the amplification factor is adjusted by the signal adjustment unit, and the sine wave signal output by the first signal adjustment unit is passed through the differential circuit in the first signal conversion unit to shift the phase by 90° to obtain a sine wave A. 1 , its phasor is expressed as U∠+30° or U∠-210°. The sine wave signal output by the third signal conditioning unit passes through the integration circuit in the second signal conversion unit, so that the phase is shifted forward by 90° to obtain the sine wave C 1 , whose phasor is expressed as U∠-30° or U∠+210°, passes through the adding circuit in the first signal integration unit, so that A 1 , B, C 1 The sine wave L1 is obtained by adding them together, and the sine wave L1 lights up the positive sequence indicator LED1; Step 32: The sine wave signal output by the first signal conditioning unit is passed through the integration circuit in the first signal conversion unit to shift the phase forward by 90° to obtain a sine wave A. 2 , its phasor is expressed as U∠+210° or U∠-30°. The sine wave signal output by the third signal conditioning unit passes through the differential circuit in the second signal conversion unit, so that the phase is shifted 90° to obtain the sine wave C 2 , whose phasor is expressed as U∠-210° or U∠+30°, passes through the adding circuit in the first signal integration unit, so that A 2 , B, C 2 The addition results in a sine wave L2, which lights up the negative sequence indicator LED2; Step 33: Observe the brightness of the positive sequence indicator LED1 and the negative sequence indicator LED2.

2. A three-phase motor phase sequence detection method based on signal amplification according to claim 1, characterized in that: The power module adopts a bipolar direct current power supply composed of two 9V alkaline batteries.

3. A three-phase motor phase sequence detection method based on signal amplification according to claim 1, characterized in that: The signal acquisition unit includes a first signal acquisition unit, a second signal acquisition unit and a third signal acquisition unit. The first, second and third signal acquisition units each include a shielded wire with an alligator clip, one end of the alligator clip is respectively connected to the terminals U, V, and W of the three-phase motor, and the other end is connected to the input end of the signal amplification unit.

4. A three-phase motor phase sequence detection method based on signal amplification according to claim 1, characterized in that: The signal amplifying unit includes a first signal amplifying unit, a second signal amplifying unit and a third signal amplifying unit. The first, second and third signal amplifying units are all two-stage amplifying circuits composed of operational amplifiers and resistors; the input ends of the first, second and third signal amplifying units are correspondingly connected to the output ends of the signal acquisition unit, and their output ends are connected to the input end of the signal adjustment unit.

5. The three-phase motor phase sequence detection method based on signal amplification according to claim 1 is characterized in that: The signal adjustment unit includes a first signal adjustment unit, a second signal adjustment unit and a third signal adjustment unit. The first, second and third signal adjustment units are all amplifier circuits with adjustable voltage gains composed of operational amplifiers, resistors and potentiometers. The input ends of the first, second and third signal adjustment units are correspondingly connected to the output end of the signal amplification unit, the output ends of the first and third signal adjustment units are connected to the input end of the signal conversion unit, and the output end of the second signal adjustment unit is connected to the input end of the signal integration unit.

6. A three-phase motor phase sequence detection method based on signal amplification according to claim 1, characterized in that: The signal conversion unit includes a first signal conversion unit and a second signal conversion unit, and the first and second signal conversion units are both integration circuits and differentiation circuits composed of operational amplifiers, resistors and capacitors; wherein the input end of the first signal conversion unit is connected to the output end of the first signal adjustment unit, the input end of the second signal conversion unit is connected to the output end of the third signal adjustment unit, and the output ends of the first and second signal conversion units are connected to the signal integration unit.

7. A three-phase motor phase sequence detection method based on signal amplification according to claim 1, characterized in that: The signal integration unit includes a first signal integration unit and a second signal integration unit, and the first and second signal integration units are both addition circuits composed of operational amplifiers and resistors; wherein the input ends of the first and second signal integration units are connected to the output ends of the first signal conversion unit, the second signal conversion unit and the second signal adjustment unit, and the output ends of the first and second signal integration units are connected to the indication module.

8. The three-phase motor phase sequence detection method based on signal amplification according to claim 1 is characterized in that: The indication module includes a positive sequence indication unit and a negative sequence indication unit. The positive sequence indication unit is composed of a positive sequence indicator light LED1 and a resistor, and the negative sequence indication unit is composed of a negative sequence indicator light LED2 and a resistor. The positive sequence indication unit is connected to the output end of the first signal integration unit, and the negative sequence indication unit is connected to the output end of the second signal integration unit.

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