Current detection amplifying circuit
By introducing a detection resistor and a voltage divider circuit into the DC motor, combined with a limiting and zero-adjusting filter circuit, the problem of nonlinear error of the Hall sensor is solved, and low-cost, high-precision current detection is achieved.
Patent Information
- Application Number
- CN202422176555.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2025-10-17
- Estimated Expiration
- 2034-09-05
AI Technical Summary
In existing DC motor current detection, Hall sensors are sensitive to temperature and external magnetic fields, resulting in nonlinear errors and high costs, making it difficult to achieve high-precision and low-cost current detection.
A detection resistor, a voltage divider circuit, a limiter circuit, and a zero adjustment filter circuit are used. The voltage divider circuit limits the input voltage range, the limiter circuit prevents overvoltage damage, the zero adjustment filter circuit ensures zero output and signal accuracy, and an operational amplifier is used to amplify the current signal.
The high-precision, low-cost and anti-temperature and magnetic field interference capabilities of current detection are achieved, the circuit structure is simple, the applicability is strong, and the detection accuracy is high.
Smart Images
Figure CN223450042U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the current detection amplification circuit in the direct current motor detection technical field. BACKGROUND
[0002] Direct current motor refers to the rotary motor that can convert direct current electric energy into mechanical energy (direct current motor) or convert mechanical energy into direct current electric energy (direct current generator). It is the motor that can realize the mutual conversion of direct current electric energy and mechanical energy. When it runs as a motor, it is a direct current motor that converts electric energy into mechanical energy, and when it runs as a generator, it is a direct current generator that converts mechanical energy into electric energy. In industrial production, the fault caused by motor overcurrent has a great influence on product quality and production efficiency. Therefore, the current of the direct current motor needs to be detected to monitor its current size at all times. In the prior art, in order to detect the size of the motor current, a Hall sensor is usually connected to the motor armature, and the voltage signal output by the Hall sensor indirectly reflects the size of the motor current. However, the sensitivity of the Hall sensor to temperature and external magnetic field, the temperature change and the external magnetic field interference will affect the performance of the sensor, the relationship between the output signal and the magnetic field is not completely linear, there is a nonlinear error, and the cost is high. SUMMARY
[0003] The utility model discloses a kind of current detection amplification circuits, simple, practical, good portability, high detection precision, low cost.
[0004] To achieve the above object, the utility model provides a kind of current detection amplification circuit, including detection resistance R0, detection resistance R0 is connected in series in armature main loop, the two ends of detection resistance R0 are connected with voltage division circuit, voltage division circuit is connected with detection circuit and limiting circuit respectively, detection circuit is connected with zero adjustment filter circuit.
[0005] Compared with prior art, the utility model has the beneficial effect that the voltage loaded in the detection circuit is in the safe range by voltage division circuit, the voltage signal input to the detection circuit is controlled by limiting circuit, the detection circuit outputs a voltage signal reflecting the size of the armature current of direct current motor, the change of the voltage signal reflects the change of the current size, the circuit is simple, practical, good portability, high detection precision, low cost.
[0006] As a further improvement of the utility model, voltage division circuit includes resistance R1 and resistance R11, one end of resistance R1 is connected with A end of detection resistance R0, the other end of resistance R1 is grounded through resistance R4, one end of resistance R11 is connected with B end of detection resistance R0, the other end of resistance R11 is connected with one end of variable resistor RP2 and variable end respectively, the other end of variable resistor RP2 is grounded through resistance R12.
[0007] Thus, the voltage divider circuit is formed by R1, R4, R11 and RP, so that the input voltage of the detection circuit is reduced to a certain range when the input voltage of A (or B) is effectively divided and loaded to the input terminal of the detection circuit, thereby avoiding damage of the detection circuit caused by excessive voltage.
[0008] As a further improvement of the utility model, the detection circuit comprises a resistor R2 and a resistor R13, one end of the resistor R2 is connected with the other end of the resistor R1, the other end of the resistor R2 is connected with one end of a resistor R3 and a negative electrode of a diode V5 respectively, the other end of the resistor R3 is connected with a pin 1 of an operational amplifier Q1, a positive electrode of the diode V5 is connected with one end of the resistor R13, the other end of the resistor R13 is connected with the other end of a variable resistor RP2, the negative electrode of the diode V5 is connected with a positive electrode of a diode V6, the positive electrode of the diode V6 is connected with a pin 2 of the operational amplifier Q1, and the negative electrode of the diode V6 is connected with a pin 3 of the operational amplifier Q1 and a positive electrode of the diode V5 respectively.
[0009] Thus, a voltage output signal U1 is obtained after the signal is amplified by Q1, and the signal can reflect the change of the armature current, wherein the diodes V5 and V6 are used to protect Q1 from damage caused by a large differential mode voltage between the two input terminals of Q1.
[0010] As a further improvement of the utility model, the limiting circuit comprises a resistor R5 and a stabilizing diode VA1, one end of the resistor R5 is connected with a negative electrode of a 15V power supply, the other end of the resistor R5 is connected with a positive electrode of a diode V1, the negative electrode of the diode V1 is connected with one end of the resistor R2 and a positive electrode of a diode V2 respectively, a negative electrode of the diode V2 is connected with one end of a resistor R6, the other end of the resistor R6 is connected with a positive electrode of the 15V power supply, the negative electrode of the diode V2 is also connected with a negative electrode of a diode V4 and a negative electrode of a stabilizing diode VA2 respectively, a positive electrode of the stabilizing diode VA2 is grounded, the positive electrode of the diode V4 is connected with the other end of the resistor R13 and a negative electrode of a diode V3 respectively, the positive electrode of the diode V3 is connected with the positive electrode of the diode V1 and a negative electrode of the stabilizing diode VA1 respectively, and the positive electrode of the stabilizing diode VA1 is grounded.
[0011] Thus, the limiting circuit is formed by the two stabilizing diodes VA1 and VA2, four ordinary diodes and the 15V power supply, so that the upper limit of the potential of points C and D is fixed on the breakdown voltage of the stabilizing diode, thereby further ensuring the safety of the detection circuit.
[0012] As further improvement of the utility model, zero adjusting filter circuit includes resistance R7, one end of resistance R7 is connected with 3 pin of operational amplifier Q1, the other end of resistance R7 is connected with one end of resistance R10 and one end of resistance R9 respectively, the other end of resistance R10 is connected with variable end of rheostat RP1, one end of rheostat RP1 is connected with negative pole of 15V power supply, the other end is grounded, the other end of resistance R9 is connected with one end of capacitor C1 and grounded, the other end of capacitor C1 is connected with one end of resistance R8, the other end of resistance R8 is connected with 1 pin of operational amplifier Q1.
[0013] In this way, R7, R9, R10 and RP1 are used to adjust zero, to ensure that the output of operational amplifier Q1 is also zero when the input signal is zero, that is, zero output, thereby improving the output precision, and the output signal of Q1 is filtered through capacitor C1, thereby ensuring the accuracy of the output signal. BRIEF DESCRIPTION OF DRAWINGS
[0014] Figure 1 The utility model circuit diagram. DETAILED DESCRIPTION
[0015] The utility model is further described below in connection with the drawings:
[0016] As Figure 1 shown in a kind of current detection amplification circuit, including detection resistance R0, detection resistance R0 is connected in armature main loop, the two ends of detection resistance R0 are connected with voltage division circuit, voltage division circuit is connected with detection circuit and limiting circuit respectively, detection circuit is connected with zero adjusting filter circuit. Voltage division circuit includes resistance R1 and resistance R11, one end of resistance R1 is connected with the A end of detection resistance R0, the other end of resistance R1 is grounded via resistance R4, one end of resistance R11 is connected with the B end of detection resistance R0, the other end of resistance R11 is connected with one end and variable end of rheostat RP2 respectively, the other end of rheostat RP2 is grounded via resistance R12.
[0017] Detection circuit includes resistance R2 and resistance R13, one end of resistance R2 is connected with the other end of resistance R1, the other end of resistance R2 is connected with one end of resistance R3 and the negative pole of diode V5 respectively, the other end of resistance R3 is connected with 1 pin of operational amplifier Q1, the positive pole of diode V5 is connected with one end of resistance R13, the other end of resistance R13 is connected with the other end of rheostat RP2, the negative pole of diode V5 is connected with the positive pole of diode V6, the positive pole of diode V6 is connected with 2 pin of operational amplifier Q1, the negative pole of diode V6 is connected with 3 pin of operational amplifier Q1 and the positive pole of diode V5 respectively.
[0018] The limiting circuit comprises a resistor R5 and a voltage stabilizing diode VA1, one end of the resistor R5 is connected with the negative pole of a 15V power supply, the other end of the resistor R5 is connected with the positive pole of the diode V1, the negative pole of the diode V1 is connected with one end of the resistor R2 and the positive pole of the diode V2 respectively, the negative pole of the diode V2 is connected with one end of the resistor R6, the other end of the resistor R6 is connected with the positive pole of the 15V power supply, the negative pole of the diode V2 is also connected with the negative pole of the diode V4 and the negative pole of the voltage stabilizing diode VA2 respectively, the positive pole of the voltage stabilizing diode VA2 is grounded, the positive pole of the diode V4 is connected with the other end of the resistor R13 and the negative pole of the diode V3 respectively, the positive pole of the diode V3 is connected with the positive pole of the diode V1 and the negative pole of the voltage stabilizing diode VA1 respectively, and the positive pole of the voltage stabilizing diode VA1 is grounded.
[0019] The zero adjusting filter circuit comprises a resistor R7, one end of the resistor R7 is connected with the pin 3 of an operational amplifier Q1, the other end of the resistor R7 is connected with one end of a resistor R10 and one end of a resistor R9 respectively, the other end of the resistor R10 is connected with the variable end of a variable resistor RP1, one end of the variable resistor RP1 is connected with the negative pole of a 15V power supply, the other end is grounded, the other end of the resistor R9 is connected with one end of a capacitor C1 and grounded, the other end of the capacitor C1 is connected with one end of a resistor R8, and the other end of the resistor R8 is connected with the pin 1 of the operational amplifier Q1.
[0020] In the utility model, a detection resistor R0 is connected in series in the armature main loop of the direct current motor, the resistance of the resistor is less than 1 ohm, points A and B in the circuit are connected at the two ends of the resistor, the potential drop at the two ends is obtained, a voltage dividing circuit is composed of R1, R4, R11 and RP, the voltage dividing ratio is set according to the model of the direct current motor, so that when the input voltage of A (or B) end to ground changes in the range of 0-100V, the common mode input voltage of the operational amplifier Q1 is limited in the range of 0-10V (because the common mode input voltage of the general operational amplifier cannot exceed 0-10V). In order to prevent the input voltage of A (or B) end to ground from being too large and being unfavorable to the operational amplifier Q1, a limiting circuit is formed by two voltage stabilizing diodes VA1 and VA2, four general diodes and a 15V power supply, the breakdown voltage of the voltage stabilizing diodes VA1 and VA2 can be 6.8V, so that the potential of points C and D can be limited in the range of 0-6.8V. In this way, the voltage at the two ends of the detection resistor R0 is divided and limited, the signal is amplified by the operational amplifier Q1, and a voltage output signal U1 is obtained, which can reflect the change of the armature current.
[0021] R7, R9, R10 and RP1 are used to zero, to ensure that the operational amplifier Q1 in the input signal is zero, the output is also zero, namely zero output, so as to improve the output accuracy, and also through the capacitor C1 to filter the output signal of Q1, so as to ensure the accuracy of the output signal, diode V5 and V6 are used to protect the operational amplifier Q1, prevent the operational amplifier Q1 between the two input terminals appear larger differential mode voltage and damage.
[0022] The utility model discloses, circuit structure is simple, the cost of each component is low, and the overall safety of circuit is good, and temperature change and outside magnetic field interference will not cause the interference of circuit.
[0023] The utility model is not limited to the above-mentioned embodiment, on the basis of the technical scheme of the disclosure, the skilled in the art can make some replacement and deformation to some technical features in the disclosed technical content without creative labor, and these replacement and deformation are all within the protection scope of the utility model.
Claims
1. A current detection amplifier circuit, characterized in that: It includes a detection resistor R0, which is connected in series in the armature main circuit. Both ends of the detection resistor R0 are connected to a voltage divider circuit. The voltage divider circuit is respectively connected to the detection circuit and the limiter circuit. The detection circuit is connected to the zero adjustment filter circuit.
2. The current detection amplifier circuit according to claim 1, wherein: The voltage divider circuit includes resistors R1 and R11. One end of the resistor R1 is connected to the A end of the detection resistor R0, and the other end of the resistor R1 is grounded via the resistor R4. One end of the resistor R11 is connected to the B end of the detection resistor R0, and the other end of the resistor R11 is respectively connected to one end and the variable end of the variable resistor RP2. The other end of the variable resistor RP2 is grounded via the resistor R12.
3. The current detection amplifier circuit according to claim 2, wherein: The detection circuit includes a resistor R2 and a resistor R13. One end of the resistor R2 is connected to the other end of the resistor R1, and the other end of the resistor R2 is respectively connected to one end of the resistor R3 and the cathode of the diode V5. The other end of the resistor R3 is connected to pin 1 of the operational amplifier Q1. The anode of the diode V5 is connected to one end of the resistor R13. The other end of the resistor R13 is connected to the other end of the variable resistor RP2. The cathode of the diode V5 is connected to the anode of the diode V6. The anode of the diode V6 is connected to pin 2 of the operational amplifier Q1. The cathode of the diode V6 is respectively connected to pin 3 of the operational amplifier Q1 and the anode of the diode V5.
4. The current detection amplifier circuit according to claim 3, wherein: The amplitude limiting circuit includes a resistor R5 and a Zener diode VA1. One end of the resistor R5 is connected to the negative electrode of the 15V power supply, the other end of the resistor R5 is connected to the positive electrode of the diode V1, the negative electrode of the diode V1 is respectively connected to one end of the resistor R2 and the positive electrode of the diode V2, the negative electrode of the diode V2 is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the positive electrode of the 15V power supply, the negative electrode of the diode V2 is also respectively connected to the negative electrode of the diode V4 and the negative electrode of the Zener diode VA2, the positive electrode of the Zener diode VA2 is grounded, the positive electrode of the diode V4 is respectively connected to the other end of the resistor R13 and the negative electrode of the diode V3, the positive electrode of the diode V3 is respectively connected to the positive electrode of the diode V1 and the negative electrode of the Zener diode VA1, and the positive electrode of the Zener diode VA1 is grounded.
5. The current detection amplifier circuit according to claim 4, wherein: The zero adjustment filter circuit includes a resistor R7, one end of which is connected to pin 3 of the operational amplifier Q1, the other end of which is connected to one end of a resistor R10 and one end of a resistor R9 respectively, the other end of which is connected to the variable end of a variable resistor RP1, one end of which is connected to the negative electrode of a 15V power supply and the other end is grounded, the other end of the resistor R9 is connected to one end of a capacitor C1 and to ground, the other end of the capacitor C1 is connected to one end of a resistor R8, and the other end of the resistor R8 is connected to pin 1 of the operational amplifier Q1.