Motor safety protection circuit for monitoring current

Abstract

The utility model relates to the technical field of power utilization protection, in particular to a motor safety protection circuit for monitoring current, which comprises a sampling module, a signal amplification module, an output module and a control module, the differential pressure sensor is used for monitoring the differential pressure of the sampling resistor and performing signal processing on the differential pressure of the resistor; the output module is connected with the output end of the signal amplification module and outputs the signal to the control module; the control module comprises a chip, and the chip calculates and outputs the current of the tested equipment according to the voltage difference of the sampling resistor processed by the signal amplification module. According to the utility model, access current is collected through the low-side sampling resistor, and the amplification circuit is built based on the instrument operational amplifier, so that the high amplification gain is realized, the interference can be shielded, the real-time monitoring of the current is realized, the cost is low, and the safety is higher.

Description

Technical Field

[0001] This utility model relates to the field of electrical protection technology, specifically to a motor safety protection circuit for monitoring current. Background Technology

[0002] Currently available motor current safety monitoring circuits are generally integrated current monitoring systems for servo motors, and the software can retrieve this value via commands. Another option might be to use a resettable fuse, which trips when the detected current exceeds the limit.

[0003] For example, the invention patent CN104078922B discloses a short-circuit protection device, which includes a first terminal, a second terminal, a third terminal, and a fourth terminal; a first voltage stabilizing element disposed between the first terminal and the second terminal; and a first disconnecting device disposed between the second terminal and the third terminal. The first disconnecting device is configured to disconnect when the current flowing through it exceeds a predetermined first current threshold. The first disconnecting device is a fuse or a self-resetting circuit protection element.

[0004] This solution can only trigger protection when the limit is reached, and cannot monitor the current in real time. However, retrieving the servo motor's current value through software has drawbacks such as high cost, software dependence, and poor real-time response.

[0005] Therefore, there is an urgent need for a motor safety protection circuit that monitors current. Utility Model Content

[0006] To overcome the problems existing in the prior art, the purpose of this utility model is to provide a motor safety protection circuit for monitoring current. On the one hand, it can monitor the differential pressure of components in real time to calculate the current, and use the current value to determine whether the load on the components is normal, and whether there is an excessive or insufficient load.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a motor safety protection circuit for monitoring current, comprising:

[0008] The sampling module includes a sampling resistor R64 connected in series with the device under test, and the sampling module is used to collect the current of the device under test;

[0009] A signal amplification module is connected in parallel across the sampling resistor R64 to monitor the voltage difference across the sampling resistor R64 and to perform signal processing on the voltage difference across the sampling resistor R64.

[0010] An output module is connected to the output terminal of the signal amplification module and is used to output a signal to the control module;

[0011] The control module includes a chip that calculates and outputs the current of the device under test based on the voltage difference of the sampling resistor R64 after processing by the signal amplification module.

[0012] The present invention is further configured such that: the sampling module includes a device under test and a sampling resistor R64; one end of the device under test is connected to the device power supply, and the other end is connected to the first end of the sampling resistor R64, and the second end of the sampling resistor R64 is grounded.

[0013] The present invention is further configured such that the signal amplification module is an amplification circuit built by an instrumentation operational amplifier.

[0014] The present invention is further configured such that the signal amplification module includes an instrumentation amplifier U9, a resistor R48, a resistor R49, a capacitor C50, a capacitor C52, and a capacitor C53;

[0015] The first end of the resistor R48 is connected to the first end of the sampling resistor R64, the second end of the resistor R48 is connected to the first end of the capacitor C52 and the positive input terminal of the instrumentation amplifier U9, and the second end of the capacitor C52 is grounded.

[0016] The first end of resistor R49 is connected to the second end of sampling resistor R64, and the second end of resistor R49 is connected to the first end of capacitor C53 and the negative input terminal of instrumentation amplifier U9 respectively; the second end of capacitor C53 is grounded; the first end of capacitor C50 is connected to resistor R48, and the second end of capacitor C50 is connected to resistor R49.

[0017] The signal amplification module also includes a gain resistor R66, a capacitor C59, and an inductor FB13; the gain resistor R66 is connected between the gain pin RG1 and the gain pin RG2 of the instrumentation amplifier U9; the positive voltage supply terminal of the instrumentation amplifier U9 is connected to the power supply and the capacitor C59 respectively, and the capacitor C59 is grounded; the negative voltage supply terminal of the instrumentation amplifier U9 is grounded.

[0018] The present invention is further configured such that the instrumentation amplifier U9 is an AD8226 instrumentation amplifier.

[0019] The present invention is further configured such that: the output module includes a resistor R68 and a capacitor C63; the first end of the resistor R68 is connected to the voltage output terminal VOUT of the instrumentation amplifier U9, the second end of the resistor R68 is connected to the first end of the capacitor C63 and the control module respectively, and the capacitor C63 is grounded.

[0020] The present invention is further configured such that the chip is an ADC chip, used to convert analog signals into digital information.

[0021] This invention collects the voltage flowing through the sampling resistor R64, amplifies and processes it, and outputs the processed signal to the ADC chip. The chip can determine the current in the path based on the collected voltage. If the current reaches or exceeds the preset safety threshold, the control module cuts off the power switch of the device.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention collects the current in the path through a low-side sampling resistor and builds an amplification circuit based on an instrumentation operational amplifier. It has both strong amplification gain and can shield interference, achieving real-time current monitoring while being low-cost and safer. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The circuit diagram is shown in the embodiment of the motor safety protection circuit for monitoring current. Detailed Implementation

[0026] The technical solution of this utility model will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of this utility model. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0028] Example:

[0029] like Figure 1 As shown, a preferred embodiment of the present invention is provided, a motor safety protection circuit for monitoring current, comprising:

[0030] The sampling module includes a sampling resistor R64 connected in series with the device under test, and the sampling module is used to collect the current of the device under test;

[0031] A signal amplification module is connected in parallel across the sampling resistor R64 to monitor the voltage difference across the sampling resistor R64 and to perform signal processing on the voltage difference across the sampling resistor R64.

[0032] An output module is connected to the output terminal of the signal amplification module and is used to output a signal to the control module;

[0033] The control module includes a chip that calculates and outputs the current of the device under test based on the voltage difference of the sampling resistor R64 after processing by the signal amplification module. The chip is an ADC chip, used to convert analog signals into digital information.

[0034] By collecting the voltage flowing through the sampling resistor R64, amplifying and processing it, and outputting the processed signal to the ADC chip, the chip can determine the current in the path based on the collected voltage. If the current reaches or exceeds the preset safety threshold, the control module cuts off the power switch of the device under test.

[0035] The sampling module includes a device under test and a sampling resistor R64; one end of the device under test is connected to the device power supply, and the other end is connected to the first end of the sampling resistor R64, while the second end of the sampling resistor R64 is grounded.

[0036] The device power input is supplied to the device under test to support its operation. A sampling resistor R64 is added to the ground terminal. Since this resistor is connected in series in the circuit, the current flowing through the sampling resistor R64 is equal to the current flowing through the device under test.

[0037] The signal amplification module is an amplification circuit built using instrumentation operational amplifiers.

[0038] In this embodiment, the instrumentation amplifier U9 is the AD8226 instrumentation amplifier.

[0039] The signal amplification module includes an instrumentation amplifier U9, resistors R48 and R49, capacitors C50, C52, and C53;

[0040] The first end of the resistor R48 is connected to the first end of the sampling resistor R64, the second end of the resistor R48 is connected to the first end of the capacitor C52 and the positive input terminal of the instrumentation amplifier U9, and the second end of the capacitor C52 is grounded.

[0041] The first end of the resistor R49 is connected to the second end of the sampling resistor R64, and the second end of the resistor R49 is connected to the first end of the capacitor C53 and the negative input terminal of the instrumentation amplifier U9; the second end of the capacitor C53 is grounded.

[0042] The first terminal of capacitor C50 is connected to resistor R48, and the second terminal of capacitor C50 is connected to resistor R49.

[0043] The signal amplification module also includes a gain resistor R66, a capacitor C59, and an inductor FB13; the gain resistor R66 is connected between the gain pin RG1 and the gain pin RG2 of the instrumentation amplifier U9; the positive voltage supply terminal of the instrumentation amplifier U9 is connected to the power supply and the capacitor C59 respectively, and the capacitor C59 is grounded; the negative voltage supply terminal of the instrumentation amplifier U9 is grounded.

[0044] The output module includes a resistor R68 and a capacitor C63; the first end of the resistor R68 is connected to the voltage output terminal VOUT of the instrumentation amplifier U9, the second end of the resistor R68 is connected to the first end of the capacitor C63 and the control module respectively, and the capacitor C63 is grounded.

[0045] The above technical features constitute the preferred embodiment of this utility model, which has strong adaptability and optimal implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the needs of different situations.

[0046] Finally, it should be noted that the above content is only used to illustrate the technical solution of this utility model, and is not intended to limit the scope of protection of this utility model. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of this utility model do not depart from the essence and scope of the technical solution of this utility model.

Claims

1. A motor safety circuit for monitoring current, characterized by include: The sampling module includes a sampling resistor R64 connected in series with the device under test, and the sampling module is used to collect the current of the device under test; A signal amplification module is connected in parallel across the sampling resistor R64 to monitor the voltage difference across the sampling resistor R64 and to perform signal processing on the voltage difference across the sampling resistor R64. An output module is connected to the output terminal of the signal amplification module and is used to output a signal to the control module; The control module includes a chip that calculates and outputs the current of the device under test based on the voltage difference of the sampling resistor R64 after processing by the signal amplification module.

2. A motor safety circuit for monitoring current as claimed in claim 1, wherein, The sampling module includes a device under test and a sampling resistor R64; one end of the device under test is connected to the device power supply, and the other end is connected to the first end of the sampling resistor R64, while the second end of the sampling resistor R64 is grounded.

3. The motor safety protection circuit for monitoring current according to claim 1, wherein, The signal amplification module is an amplification circuit built using instrumentation operational amplifiers.

4. A motor safety circuit for monitoring current as claimed in claim 3, wherein, The signal amplification module includes an instrumentation amplifier U9, resistors R48 and R49, capacitors C50, C52, and C53; The first end of the resistor R48 is connected to the first end of the sampling resistor R64, the second end of the resistor R48 is connected to the first end of the capacitor C52 and the positive input terminal of the instrumentation amplifier U9, and the second end of the capacitor C52 is grounded. The first end of resistor R49 is connected to the second end of sampling resistor R64, and the second end of resistor R49 is connected to the first end of capacitor C53 and the negative input terminal of instrumentation amplifier U9 respectively; the second end of capacitor C53 is grounded; the first end of capacitor C50 is connected to resistor R48, and the second end of capacitor C50 is connected to resistor R49. The signal amplification module also includes a gain resistor R66, a capacitor C59, and an inductor FB13; the gain resistor R66 is connected between the gain pin RG1 and the gain pin RG2 of the instrumentation amplifier U9; the positive voltage supply terminal of the instrumentation amplifier U9 is connected to the power supply and the capacitor C59 respectively, and the capacitor C59 is grounded; the negative voltage supply terminal of the instrumentation amplifier U9 is grounded.

5. A motor safety circuit for monitoring current as defined in claim 4, wherein, The instrumentation amplifier U9 is an AD8226 instrumentation amplifier.

6. A motor safety circuit for monitoring current as defined in claim 4, wherein, The output module includes a resistor R68 and a capacitor C63; the first end of the resistor R68 is connected to the voltage output terminal VOUT of the instrumentation amplifier U9, the second end of the resistor R68 is connected to the first end of the capacitor C63 and the control module respectively, and the capacitor C63 is grounded.

7. The motor safety protection circuit of claim 1, wherein the current monitoring circuit further comprises a current transformer. The chip is an ADC chip, used to convert analog signals into digital information.

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