CN211826207U - High-end side sampling circuit of motor current - Google Patents
High-end side sampling circuit of motor current Download PDFInfo
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- CN211826207U CN211826207U CN201921881610.1U CN201921881610U CN211826207U CN 211826207 U CN211826207 U CN 211826207U CN 201921881610 U CN201921881610 U CN 201921881610U CN 211826207 U CN211826207 U CN 211826207U
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Abstract
The utility model relates to a high-end side sampling circuit of motor current, including reference voltage circuit, sampling resistance bleeder circuit, common mode voltage cancelling circuit and differential voltage amplifier circuit, the high-end side of motor current is received to sampling resistance bleeder circuit, and common mode voltage cancelling circuit is received to sampling resistance bleeder circuit's output, and differential voltage amplifier circuit is received to common mode voltage cancelling circuit's output, and reference voltage circuit is also connected to differential voltage amplifier circuit, and sampling circuit's output is regarded as to differential voltage amplifier circuit's output. The high-end side sampling circuit of the motor current eliminates the high common-mode voltage interference of the high-end side sampling of the motor current through the common-mode voltage eliminating circuit, and has the advantages of strong practicability, good anti-interference performance, high sampling bandwidth, safety and reliability.
Description
Technical Field
The invention belongs to the field of motor control, and relates to a high-side sampling circuit of motor current.
Background
The current loop is an inner loop controlled by the servo motor, the control effect of the current loop influences the control effect of the servo motor, and high-quality motor current sampling is the premise of current control. The sampling of the motor current of a small system usually adopts a mode of voltage division by serially connected sampling resistors, and the voltage division by the sampling resistors has two modes of sampling at the high end side of the motor current and sampling at the low end side of the motor current. The advantages of low common mode voltage and simple back-end processing circuit are that the sampling at the low end of the motor current requires high sampling time sequence and requires a sampling program to reconstruct the motor current. The high-end side of the current of the motor is sampled, the current flowing through the sampling resistor is the current of the motor, the sampling time sequence has no strict requirement, but the common-mode voltage at the two ends of the sampling resistor is higher, and the sampling circuit needs to eliminate the interference of the high common-mode voltage. The high-side sampling of the motor current often eliminates the interference of high common-mode voltage in a mode of resistor network voltage division, but the resistor network voltage division simultaneously attenuates effective signals, thereby reducing the sampling bandwidth.
Disclosure of Invention
Technical problem to be solved
In order to avoid the defects of the prior art, the invention provides a high-side sampling circuit of motor current, and provides the high-side sampling circuit of motor current, which has strong practicability, strong common-mode interference resistance and high sampling bandwidth.
Technical scheme
A high-side sampling circuit of motor current is characterized by comprising a reference voltage circuit, a sampling resistor voltage division circuit, a common-mode voltage elimination circuit and a differential voltage amplification circuit; the sampling resistance voltage division circuit is connected to the high-end side of the motor current, the output of the sampling resistance voltage division circuit is connected to the common-mode voltage elimination circuit, the output of the common-mode voltage elimination circuit is connected to the reference voltage circuit, and the output of the differential voltage amplification circuit is used as the output of the sampling circuit; the sampling resistor voltage division circuit comprises an Rs resistor, an R1 resistor, an R2 resistor and a C1 capacitor, wherein the two ends of the Rs resistor are connected with the R1 resistor and the R2 resistor in parallel to form an n-shaped circuit, the C1 capacitor is connected to the other ends of the R1 resistor and the R2 resistor in parallel, the parallel end of the R1 resistor is a positive output end V01+ of the resistor voltage division circuit, the parallel end of the R2 resistor is a negative output end V01-, and the Rs resistor is connected to the high-end side of the motor current in series; the common mode voltage elimination circuit comprises a U1 operational amplifier, an R3 resistor, an R4 resistor, an R5 resistor, an R6 resistor, a Q1PNP triode, a Q2PNP triode, an R7 resistor and an R8 resistor; a V01+ signal is input into the positive input end of the U1 operational amplifier through an R4 resistor, a V01-signal is input into the negative input end of the U1 operational amplifier through an R3 resistor, the positive output end of the U1 operational amplifier is connected with the base electrode of the Q1PNP triode, and the reverse output end of the U1 operational amplifier is connected with the base electrode of the Q2PNP triode; the power supply VCC is connected with the negative input end of the U1 operational amplifier and the emitting electrode of the Q1PNP triode through an R5 resistor, and is connected with the positive input end of the U1 operational amplifier and the emitting electrode of the Q2PNP triode through an R6 resistor; the R7 resistor and the R8 resistor are connected in series and then connected in parallel with the collector of the Q1PNP triode, namely the negative output end V02-of the common mode voltage elimination circuit, and the collector of the Q2PNP triode, namely the positive output end V02+ of the common mode voltage elimination circuit, and a tap of the series resistor is grounded; the differential voltage amplifying circuit comprises a U2 operational amplifier, an R9 resistor, an R11 resistor, an R10 resistor, an R12 resistor, an R13 resistor and a C2 capacitor; the signal V02-is connected with the negative input end of the U2 operational amplifier through the R9 resistor, the signal V02+ is connected with the positive input end of the U2 operational amplifier through the R11 resistor, the output end of the U2 operational amplifier is connected with the output end of the filter circuit of the R13 resistor and the C2 capacitor to output the output signal VOUT of the high-end side sampling circuit, the R10 resistor is connected with the negative input end of the operational amplifier U2 and the output end of the operational amplifier U2 in parallel, and the R12 resistor is connected with the output end of the reference voltage circuit.
The reference voltage circuit comprises a U3 operational amplifier, a R14 resistor, a R15 resistor, a D1 zener diode and a C3 capacitor; the R14 resistor and the R15 resistor are power supply voltage dividing resistors, a center tap is connected with the positive input end of the U3 operational amplifier, the D1 voltage stabilizing diode is connected in parallel with two ends of the R15 resistor, and the negative end of the D1 voltage stabilizing diode is connected with the positive input end of the U3 operational amplifier; the output end of the U3 operational amplifier is connected with the inverting input end of the operational amplifier U3 and is grounded through a capacitor C3; the output end of the U3 operational amplifier is the reference voltage output end of the reference voltage circuit.
Advantageous effects
The invention provides a high-end side sampling circuit of motor current, which comprises a reference voltage circuit, a sampling resistor voltage division circuit, a common-mode voltage elimination circuit and a differential voltage amplification circuit, wherein the sampling resistor voltage division circuit is connected to the high-end side of the motor current, the output of the sampling resistor voltage division circuit is connected to the common-mode voltage elimination circuit, the output of the common-mode voltage elimination circuit is connected to the differential voltage amplification circuit, the differential voltage amplification circuit is also connected with the reference voltage circuit, and the output of the differential voltage amplification circuit is used as the output of the sampling circuit. The high-end side sampling circuit of the motor current eliminates the high common-mode voltage interference of the high-end side sampling of the motor current through the common-mode voltage eliminating circuit, and has the advantages of strong practicability, good anti-interference performance, high sampling bandwidth, safety and reliability.
Drawings
Fig. 1 is a schematic diagram of the position of the high-side sampling resistor of the motor current of the present invention.
Fig. 2 is a block diagram of a motor current high-end side sampling circuit according to the present invention.
FIG. 3 is a schematic diagram of a reference voltage circuit according to the present invention.
Fig. 4 is a schematic structural diagram of the sampling resistor voltage-dividing circuit of the present invention.
Fig. 5 is a schematic structural diagram of the common mode voltage cancellation circuit of the present invention.
Fig. 6 is a schematic diagram of the differential voltage amplifying circuit of the present invention.
Detailed Description
The invention will now be further described with reference to the following examples and drawings:
as shown in fig. 1, the sampling resistor in the invention is connected in series with the high-end side of the H-bridge motor power amplifier; as shown in fig. 2, the motor current high-side sampling circuit includes a reference voltage circuit, a sampling resistor voltage-dividing circuit, a common-mode voltage eliminating circuit, and a differential voltage amplifying circuit;
the sampling resistor voltage division circuit is connected to the high-end side of the motor current, and the output end of the sampling resistor voltage division circuit is connected to the input end of the common-mode voltage elimination circuit and used for collecting a required voltage signal through the sampling resistor and outputting the voltage signal to the common-mode voltage elimination circuit;
the output end of the common-mode voltage elimination circuit is connected to the input end of the differential voltage amplification circuit and is used for eliminating the common-mode noise of the voltage signal acquired by the sampling resistor;
the output end of the reference voltage circuit is connected to the input end of the differential voltage amplifying circuit and used for generating a reference bias voltage;
the output end of the differential voltage amplifying circuit is used as the output of the motor current high-end side sampling circuit and is used for amplifying the differential signal of the voltage signal acquired by the sampling resistor.
As shown in fig. 3, the reference voltage circuit includes a U3 operational amplifier, a R14 resistor, a R15 resistor, a D1 zener diode and a C3 capacitor, one end of the R14 resistor is connected to a power supply, the other end of the R14 resistor is connected to one end of the R15 resistor and the same-direction input end of the U3 operational amplifier, the other end of the R15 resistor is grounded, the D1 zener diode is connected in parallel to both ends of the R15 resistor, the output end of the U3 operational amplifier is connected to the reverse-direction input end of the U3 operational amplifier, the output end of the U3 operational amplifier is grounded through the C3 capacitor, and the output end of the U3 operational amplifier is used as the output end Vref of the reference voltage circuit and;
as shown in fig. 4, the sampling resistor voltage dividing circuit includes a sampling Rs resistor, a R1 resistor, a R2 resistor and a C1 capacitor, the sampling Rs resistor is connected in series to the high-end side of the motor current, one end of the sampling Rs resistor is connected to one end of a R1 resistor, the other end of the sampling Rs resistor is connected to one end of a R2 resistor, the other end of the R1 resistor is used as the positive output terminal Vo1+ of the sampling resistor voltage dividing circuit and is connected to the common mode voltage eliminating circuit, the other end of the R2 resistor is used as the negative output terminal Vo 1-of the sampling resistor voltage dividing circuit and is connected to the common mode voltage eliminating circuit, one end of the C1 capacitor is connected to the positive output terminal Vo1+ of the sampling resistor voltage dividing circuit, and the other end;
as shown in fig. 5, the common mode voltage cancellation circuit includes a U1 operational amplifier, a R3 resistor, a resistor R4, a R5 resistor, a R6 resistor, a Q1PNP transistor, a Q2PNP transistor, a R7 resistor, and a R8 resistor. The reverse input end of the U1 operational amplifier is connected with the negative output end Vo1 of the sampling resistance voltage division circuit through an R3 resistor, the forward input end of the U1 operational amplifier is connected with the positive output end Vo1 of the sampling resistance voltage division circuit through an R4 resistor, the forward output end of the U1 operational amplifier is connected with the base electrode of the Q1PNP triode, the reverse output end of the U1 operational amplifier is connected with the base electrode of the Q2PNP triode, the emitter electrode of the Q1P NP triode is connected with the reverse input end of the U1 operational amplifier, the collector electrode of the Q1PNP triode is used as the negative output end Vo 2-of the common mode voltage elimination circuit and is connected with the differential voltage amplification circuit, the negative output end Vo 2-of the common mode voltage elimination circuit is grounded through an R7 resistor, the emitter electrode of the Q2PNP triode is connected with the forward input end of the U1 operational amplifier, the collector electrode of, the positive output end Vo2+ R8 of the common mode voltage elimination circuit is grounded through a resistor, one end of a R5 resistor is connected with the reverse input end of the U1 operational amplifier, the other end of the R5 resistor is connected with a power supply, one end of a R6 resistor is connected with the positive input end of the U1 operational amplifier, and the other end of the R6 resistor is connected with the power supply;
as shown in fig. 6, the differential voltage amplifying circuit includes a U2 operational amplifier, a R9 resistor, a R11 resistor, a R10 resistor, a R12 resistor, a R13 resistor, and a C2 capacitor. The inverting input end of the U2 operational amplifier is connected with the negative output end Vo2 of the common mode voltage eliminating circuit through an R9 resistor, the homodromous input end of the U2 operational amplifier is connected with the positive output end Vo2+ of the common mode voltage eliminating circuit through an R11 resistor, a R10 resistor is connected in parallel with the inverting input end of the U2 operational amplifier and the output end of the U2 operational amplifier, one end of the R12 resistor is connected with the positive input end of the U2 operational amplifier, the other end of the R12 resistor is connected with the output end Vref of the reference voltage circuit, one end of the R13 resistor is connected with the output end of the operational amplifier U2, the other end of the R13 resistor is used as the output end Vout of the differential voltage amplifying circuit, and.
When the differential voltage amplifier works, the sampling resistor voltage division circuit is connected to the high-end side of the motor current, an output signal of the sampling resistor voltage division circuit is input into the common-mode voltage elimination circuit, and the output end of the common-mode voltage elimination circuit is connected to the input end of the differential voltage amplification circuit and used for eliminating common-mode noise of a voltage signal acquired by the sampling resistor; the output end of the reference voltage circuit is connected to the input end of the differential voltage amplifying circuit and used for generating a reference bias voltage; the output end of the differential voltage amplifying circuit is used as the output of the motor current high-end side sampling circuit and is used for amplifying the differential signal of the voltage signal acquired by the sampling resistor.
Claims (2)
1. A high-side sampling circuit of motor current is characterized by comprising a reference voltage circuit, a sampling resistor voltage division circuit, a common-mode voltage elimination circuit and a differential voltage amplification circuit; the sampling resistance voltage division circuit is connected to the high-end side of the motor current, the output of the sampling resistance voltage division circuit is connected to the common-mode voltage elimination circuit, the output of the common-mode voltage elimination circuit is connected to the reference voltage circuit, and the output of the differential voltage amplification circuit is used as the output of the sampling circuit; the sampling resistor voltage division circuit comprises an Rs resistor, an R1 resistor, an R2 resistor and a C1 capacitor, wherein the two ends of the Rs resistor are connected with the R1 resistor and the R2 resistor in parallel to form an n-shaped circuit, the C1 capacitor is connected to the other ends of the R1 resistor and the R2 resistor in parallel, the parallel end of the R1 resistor is a positive output end V01+ of the resistor voltage division circuit, the parallel end of the R2 resistor is a negative output end V01-, and the Rs resistor is connected to the high-end side of the motor current in series; the common mode voltage elimination circuit comprises a U1 operational amplifier, an R3 resistor, an R4 resistor, an R5 resistor, an R6 resistor, a Q1PNP triode, a Q2PNP triode, an R7 resistor and an R8 resistor; a V01+ signal is input into the positive input end of the U1 operational amplifier through an R4 resistor, a V01-signal is input into the negative input end of the U1 operational amplifier through an R3 resistor, the positive output end of the U1 operational amplifier is connected with the base electrode of the Q1PNP triode, and the reverse output end of the U1 operational amplifier is connected with the base electrode of the Q2PNP triode; the power supply VCC is connected with the negative input end of the U1 operational amplifier and the emitting electrode of the Q1PNP triode through an R5 resistor, and is connected with the positive input end of the U1 operational amplifier and the emitting electrode of the Q2PNP triode through an R6 resistor; the R7 resistor and the R8 resistor are connected in series and then connected in parallel with the collector of the Q1PNP triode, namely the negative output end V02-of the common mode voltage elimination circuit, and the collector of the Q2PNP triode, namely the positive output end V02+ of the common mode voltage elimination circuit, and a tap of the series resistor is grounded; the differential voltage amplifying circuit comprises a U2 operational amplifier, an R9 resistor, an R11 resistor, an R10 resistor, an R12 resistor, an R13 resistor and a C2 capacitor; the signal V02-is connected with the negative input end of the U2 operational amplifier through the R9 resistor, the signal V02+ is connected with the positive input end of the U2 operational amplifier through the R11 resistor, the output end of the U2 operational amplifier is connected with the output end of the filter circuit of the R13 resistor and the C2 capacitor to output the output signal VOUT of the high-end side sampling circuit, the R10 resistor is connected with the negative input end of the operational amplifier U2 and the output end of the operational amplifier U2 in parallel, and the R12 resistor is connected with the output end of the reference voltage circuit.
2. The high-side sampling circuit of motor current of claim 1, wherein: the reference voltage circuit comprises a U3 operational amplifier, a R14 resistor, a R15 resistor, a D1 zener diode and a C3 capacitor; the R14 resistor and the R15 resistor are power supply voltage dividing resistors, a center tap is connected with the positive input end of the U3 operational amplifier, the D1 voltage stabilizing diode is connected in parallel with two ends of the R15 resistor, and the negative end of the D1 voltage stabilizing diode is connected with the positive input end of the U3 operational amplifier; the output end of the U3 operational amplifier is connected with the inverting input end of the operational amplifier U3 and is grounded through a capacitor C3; the output end of the U3 operational amplifier is the reference voltage output end of the reference voltage circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921881610.1U CN211826207U (en) | 2019-11-04 | 2019-11-04 | High-end side sampling circuit of motor current |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921881610.1U CN211826207U (en) | 2019-11-04 | 2019-11-04 | High-end side sampling circuit of motor current |
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| CN211826207U true CN211826207U (en) | 2020-10-30 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114236221A (en) * | 2021-10-13 | 2022-03-25 | 北京华峰测控技术股份有限公司 | Differential voltage measurement circuit, device and method |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114236221A (en) * | 2021-10-13 | 2022-03-25 | 北京华峰测控技术股份有限公司 | Differential voltage measurement circuit, device and method |
| CN114236221B (en) * | 2021-10-13 | 2023-09-26 | 北京华峰测控技术股份有限公司 | Differential voltage measurement circuit, device and method |
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