0-20mA current source speed regulation circuit and motor

Abstract

The utility model discloses a 0-20mA current source speed regulation circuit and a motor, which comprise a two-channel operational amplifier current source circuit, and are characterized in that the 0-20mA current source speed regulation circuit further comprises an input voltage adjustable circuit and an ADC sampling circuit, the output end Uin of the input voltage adjustable circuit is connected with the signal input end of the two-channel operational amplifier current source circuit, and the output end Uout of the ADC sampling circuit is connected with the output end Uout of the two-channel operational amplifier current source circuit. The output end Uin of the input voltage adjustable circuit is connected with the signal input end of the ADC sampling circuit, and the ADC sampling circuit and the dual-channel operational amplifier current source circuit respectively output a path of signal. The two-channel operational amplifier current source circuit is high in precision and low in cost, the input voltage adjustable circuit can be conveniently and manually adjusted, the size of the output current of the two-channel operational amplifier current source can be adjusted, operation is practical and convenient, and the size of the output current of the constant current source can be known in real time by means of the ADC sampling circuit.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of 0-20mA current source speed regulation circuit and motor. BACKGROUND

[0002] Current 4-20mA speed regulation circuit is widely used in industry, and most of the schemes use high-precision 4-20mA dedicated chip, which is relatively high in cost. Major manufacturers are seeking a lower-cost, precision-meeting solution with strong replaceability. To solve the above problems, a popular 0-20mA speed regulation circuit based on HOWLAND current source improved by dual-channel operational amplifier.

[0003] The 0-20mA speed regulation circuit based on HOWLAND current source improved by dual-channel operational amplifier has a circuit structure as shown in Figure 1 R1 is the reverse input resistor of the operational amplifier, R3 is the same-phase input resistor, resistors R1 and R2 form a negative feedback circuit, resistors R3 and R4 form a positive feedback circuit, RO is the output resistor of the operational amplifier, RL is the load, and Uin+, Uin- are the input signals of the operational amplifier. The following formula can be obtained from Kirchhoff's law and the concepts of virtual short and virtual open:

[0004]

[0005] This formula shows that the current size is independent of the load size, so a precise current source can be obtained by selecting the right resistor. Therefore, a stable, high-precision and low-cost 0-20m speed regulation scheme can be designed based on this principle.

[0006] Although the above-mentioned technical scheme of dual-channel operational amplifier based on HOWLAND current source can obtain a stable current source, the current size is fixed and there is no manual adjustment circuit, which is inconvenient for actual use. SUMMARY

[0007] The utility model provides a kind of 0-20mA current source speed regulation circuit and motor, to solve the technical problem that the technical scheme of dual-channel operational amplifier based on HOWLAND current source in prior art can obtain a stable current source, but the current size is fixed, there is no manual adjustment circuit, and it is inconvenient for actual use.

[0008] The technical scheme of the utility model is implemented as follows:

[0009] A 0-20mA current source speed regulation circuit, comprising a double-channel operational amplifier current source circuit, characterized in that it further comprises an input voltage adjustable circuit and an ADC sampling circuit, the output end Uin of the input voltage adjustable circuit is connected to the signal input end of the double-channel operational amplifier current source circuit, the output end Uin of the input voltage adjustable circuit is connected to the signal input end of the ADC sampling circuit, and the ADC sampling circuit and the double-channel operational amplifier current source circuit each output a signal.

[0010] Preferably, the input voltage adjustable circuit comprises a resistor R6 and a variable resistor R9, the resistor R6 and the variable resistor R9 are connected in series across a DC power supply V and ground, respectively, and the DC power supply V is divided by the resistor R6 and the variable resistor R9 to output an input voltage adjustable circuit output end Uin.

[0011] Preferably, the ADC sampling circuit comprises an operational amplifier U1B, a resistor R5, a resistor R7 and a capacitor C3, the output end Uin of the input voltage adjustable circuit is connected to one input end of the operational amplifier U1B, the output end of the operational amplifier U1B is divided by the resistor R5 and the resistor R7 to serve as an output end MCU_O, and the capacitor C3 is connected in parallel with the resistor R7.

[0012] Preferably, the double-channel operational amplifier current source circuit comprises an operational amplifier U1A, a resistor R10, a resistor R20, a resistor R30, a resistor R40 and a resistor R8, the output end Uin of the input voltage adjustable circuit is connected to the positive input end of the operational amplifier U1A through the resistor R10, the negative input end of the operational amplifier U1A is connected to the resistor R20 and then to ground, the output end of the operational amplifier U1A is connected to the resistor R30 and then to ground, the output end of the operational amplifier U1A is fed back to the negative input end of the operational amplifier U1A through the resistor R40, and a feedback signal between the resistor R30 and the load RL is connected to the positive input end of the operational amplifier U1A through the resistor R8.

[0013] Preferably, a transistor Q1 is further arranged between the output end of the operational amplifier U1A and the resistor R30, the base of the transistor Q1 is connected to the output end of the operational amplifier U1A, the collector of the transistor Q1 is connected to a +15V power supply, and the emitter of the transistor Q1 is connected to one end of the resistor R30.

[0014] A motor, comprising a motor body and a motor controller, the motor body comprising a stator assembly and a rotor assembly, and the motor controller comprising a 0-20mA speed regulation circuit, a microprocessor, a rotor position detection circuit and an inverter circuit, characterized in that the 0-20mA speed regulation circuit adopts the 0-20mA current source speed regulation circuit, and the signals output by the ADC sampling circuit and the double-channel operational amplifier current source circuit are both connected to the signal input end of the microprocessor.

[0015] Compared with the prior art, the motor has the following advantages:

[0016] 1. The 0-20mA current source speed regulation circuit of the utility model comprises a double-channel operational amplifier current source circuit, an input voltage adjustable circuit and an ADC sampling circuit, the double-channel operational amplifier current source circuit is high in precision and low in cost, the input voltage adjustable circuit can be conveniently manually adjusted, the size of the output current of the double-channel operational amplifier current source is adjusted, the operation is convenient and practical, and the size of the output current of the constant current source can be known in real time by using the ADC sampling circuit.

[0017] 2. Other advantages of the utility model are described in detail in the embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a circuit diagram of the prior art double-channel operational amplifier based on the HOWLAND current source;

[0019] Figure 2 It is a circuit block diagram of the utility model embodiment one;

[0020] Figure 3 It is Figure 2 a corresponding circuit diagram;

[0021] Figure 4 It is a circuit block diagram of the utility model embodiment two. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the utility model embodiments clearer, the technical scheme in the utility model embodiments will be clearly and completely described below in combination with the drawings in the utility model embodiments. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0023] As Figures 2 to 3 shown, the embodiment provides a 0-20mA current source speed regulation circuit, comprising a double-channel operational amplifier current source circuit, characterized in that it further comprises an input voltage adjustable circuit and an ADC sampling circuit, the output end Uin of the input voltage adjustable circuit is connected with the signal input end of the double-channel operational amplifier current source circuit, the output end Uin of the input voltage adjustable circuit is connected with the signal input end of the ADC sampling circuit, and the ADC sampling circuit and the double-channel operational amplifier current source circuit each output a signal.

[0024] The utility model discloses a 0-20mA current source speed regulation circuit includes two -way operational amplifier current source circuit, input voltage adjustable circuit and ADC sampling circuit, and two -way operational amplifier current source circuit precision is higher and the cost is lower, and input voltage adjustable circuit can be adjusted conveniently by hand, and the size of the output current of two -way operational amplifier current source is adjusted, and the operation is practical and convenient, utilizes ADC sampling circuit, can realize real -time knowing the size of the output current of constant current source.

[0025] Preferably, the input voltage adjustable circuit includes a resistor R6 and a variable resistor R9, the resistor R6 and the variable resistor R9 are connected in series with a DC power supply V and ground at both ends, respectively, and the DC power supply V is divided by the resistor R6 and the variable resistor R9 to output an input voltage adjustable circuit output terminal Uin. By manually adjusting the size of the variable resistor R9, the size of the output current of the two-way operational amplifier current source can be adjusted, and the operation is practical and convenient.

[0026] Preferably, the ADC sampling circuit includes an operational amplifier U1B, a resistor R5, a resistor R7, and a capacitor C3, the output terminal Uin of the input voltage adjustable circuit is connected to one input terminal of the operational amplifier U1B, the output terminal of the operational amplifier U1B is divided by the resistor R5 and the resistor R7 to serve as an output terminal MCU_O, and the capacitor C3 is connected in parallel with the resistor R7. The size of the output terminal Uin of the input voltage adjustable circuit is transmitted to a microprocessor MCU for ADC sampling after being divided by the output resistor of U1B, so that the output current size of the constant current source can be known in real time.

[0027] Preferably, the two-way operational amplifier current source circuit includes an operational amplifier U1A, a resistor R10, a resistor R20, a resistor R30, a resistor R40, and a resistor R8, the output terminal Uin of the input voltage adjustable circuit is connected to the positive input terminal of the operational amplifier U1A through the resistor R10, the negative input terminal of the operational amplifier U1A is connected to the resistor R20 and then grounded, the output terminal of the operational amplifier U1A is connected to the resistor R30 and then grounded, the output terminal of the operational amplifier U1A is fed back to the negative input terminal of the operational amplifier U1A through the resistor R40, and the feedback signal between the resistor R30 and the load RL is connected to the positive input terminal of the operational amplifier U1A through the resistor R8.

[0028] By setting R10=R20=R8=R40, the load current iL=Uin / R30, so the range of the adjustable constant current source can be determined by modifying the resistor R30 and adjusting the size of the output terminal Uin of the input voltage adjustable circuit.

[0029] Preferably, the output of the operational amplifier U1A is further connected with the resistor R30, and a triode Q1 is arranged between the output of the operational amplifier U1A and the resistor R30, the base of the triode Q1 is connected with the output of the operational amplifier U1A, the collector of the triode Q1 is connected with a +15V power supply, and the emitter of the triode Q1 is connected with one end of the resistor R30. Through the triode Q1, the output current of the operational amplifier U1A can be amplified, and if the actual circuit output current is not very large, the triode Q1 can be removed to save cost, and if the accuracy requirement is relatively high, a double-channel precision operational amplifier can be selected to improve the output accuracy.

[0030] The utility model selects the operational amplifier device, can not select to use high accuracy 4-20mA special chip, reduces the peripheral electronic component while reducing the manufacturing cost.

[0031] Embodiment two:

[0032] As shown in Figure 4 The utility model discloses a motor, including motor body and motor controller, motor body includes stator subassembly and rotor subassembly, and motor controller includes 0-20mA speed regulation circuit, microprocessor, rotor position detection circuit and inverter circuit, and it is characterized in that: 0-20mA speed regulation circuit adopts the 0-20mA current source speed regulation circuit of embodiment one, and the signal of the output of ADC sampling circuit and double -channel operational amplifier current source circuit is connected to the signal input end of microprocessor.

[0033] The utility model discloses a 0-20mA current source speed regulation circuit including double -channel operational amplifier current source circuit, input voltage adjustable circuit and ADC sampling circuit, and double -channel operational amplifier current source circuit precision is higher and cost is lower, and input voltage adjustable circuit can be adjusted conveniently by hand, and the size of the output current of double -channel operational amplifier current source is adjusted, and it is convenient to operate and practical, and using ADC sampling circuit can know the size of the output current of constant current source in real time.

[0034] Finally, it should be noted that: the above embodiment is only used to illustrate the technical scheme of the utility model, and is not limited thereto; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it still can modify the technical scheme recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical scheme deviate from the spirit and scope of the technical scheme of the utility model embodiments.

Claims

1. A 0-20 mA current source speed control circuit comprising a dual channel operational amplifier current source circuit, characterized by: It also includes an input voltage adjustable circuit and an ADC sampling circuit, the output end Uin of the input voltage adjustable circuit is connected with the signal input end of the double-channel operational amplifier current source circuit, the output end Uin of the input voltage adjustable circuit is connected with the signal input end of the ADC sampling circuit, and the ADC sampling circuit and the double-channel operational amplifier current source circuit each output a signal.

2. A 0-20 mA current source speed control circuit according to claim 1, characterized in that: The input voltage adjustable circuit comprises a resistor R6 and a variable resistor R9, the resistor R6 and the variable resistor R9 are connected with a direct current power supply V and the ground in series at two ends, and the direct current power supply V is divided by the resistor R6 and the variable resistor R9 to output to form the output end Uin of the input voltage adjustable circuit.

3. A 0-20 mA current source speed control circuit according to claim 2, characterized in that: The ADC sampling circuit comprises an operational amplifier U1B, a resistor R5, a resistor R7 and a capacitor C3, the output end Uin of the input voltage adjustable circuit is connected with one input end of the operational amplifier U1B, the output end of the operational amplifier U1B is divided by the resistor R5 and the resistor R7 to serve as an output end MCU_O, and the capacitor C3 is connected with the resistor R7 in parallel.

4. A 0-20 mA current source speed control circuit according to claim 1 or 2 or 3, characterized in that: The double-channel operational amplifier current source circuit comprises an operational amplifier U1A, a resistor R10, a resistor R20, a resistor R30, a resistor R40 and a resistor R8, the output end Uin of the input voltage adjustable circuit is connected with the positive input end of the operational amplifier U1A through the resistor R10, the negative input end of the operational amplifier U1A is connected with the resistor R20 and then grounded, the output end of the operational amplifier U1A is connected with the resistor R30 and the load RL and then grounded, the output end of the operational amplifier U1A is fed back to the negative input end of the operational amplifier U1A through the resistor R40, and the feedback signal between the resistor R30 and the load RL is connected with the positive input end of the operational amplifier U1A through the resistor R8.

5. A 0-20 mA current source speed control circuit according to claim 4, characterized in that: A transistor Q1 is further arranged between the output end of the operational amplifier U1A and the resistor R30, the base of the transistor Q1 is connected with the output end of the operational amplifier U1A, the collector of the transistor Q1 is connected with a +15V power supply, and the emitter of the transistor Q1 is connected with one end of the resistor R30.

6. An electric motor comprising a motor body and a motor controller, the motor body comprising a stator assembly and a rotor assembly, the motor controller comprising a 0-20 mA speed control circuit, a microprocessor, a rotor position detection circuit, and an inverter circuit, characterized in that: The 0-20mA speed regulation circuit adopts the 0-20mA current source speed regulation circuit of any one of claims 1 to 5, and the signals output by the ADC sampling circuit and the double-channel operational amplifier current source circuit are connected with the signal input end of the microprocessor.

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