阅读说明：本技术 直流变频电流的检测电路 (Detection circuit for direct current variable frequency current ) 是由 罗淦恩 高宁 潘叶江 于 2020-06-04 设计创作，主要内容包括：本发明公开了一种直流变频电流的检测电路包括电机驱动电路和检流电路,所述电机驱动电路内电连接检流电阻,并在所述检流电阻两端外接用于放大、抬高信号的检流电路以实现全时电流检测。本发明的直流变频电流的检测电路,通过在电机驱动电路内电连接检流电阻并外接检流电路,从而实现电流全时检测,不但可以实现电路过流保护,还可以实时检测电流状态以满足电机高精准控制需求；另外,电流全时检测以外围硬件电路实现方式取代芯片实现方式,节约芯片成本,同时,由于不需通过芯片软件编程,所以还降低了软件开发难度。(The invention discloses a detection circuit of direct current variable frequency current, which comprises a motor driving circuit and a current detection circuit, wherein a current detection resistor is electrically connected in the motor driving circuit, and current detection circuits for amplifying and raising signals are externally connected to two ends of the current detection resistor so as to realize full-time current detection. According to the detection circuit of the direct current variable frequency current, the current detection resistor is electrically connected in the motor driving circuit and is externally connected with the current detection circuit, so that the current is detected in full time, the overcurrent protection of the circuit can be realized, and the current state can be detected in real time to meet the requirement of high-precision control of the motor; in addition, the current full-time detection replaces a chip implementation mode with a peripheral hardware circuit implementation mode, so that the chip cost is saved, and meanwhile, the software development difficulty is reduced because chip software programming is not needed.)

1. The utility model provides a detection circuitry of direct current frequency conversion current, its characterized in that, includes motor drive circuit (1) and examines current circuit (2), the electricity is connected in motor drive circuit (1) and is examined the current resistance, examine the external current detection circuit (2) that are used for enlarging, raising the signal in current resistance both ends in order to realize full-time current detection.

2. The detection circuit of direct current variable frequency current according to claim 1, wherein the motor driving circuit (1) comprises a bridge arm U, a bridge arm V, a bridge arm W and a motor, the bridge arm U comprises a first IGBT tube M1 and a fourth IGBT tube M4, the bridge arm V comprises a second IGBT tube M2 and a fifth IGBT tube M5, the bridge arm W comprises a third IGBT tube M3 and a sixth IGBT tube M6, the first IGBT tube M1 and the fourth IGBT tube M4 are connected in parallel and then connected with the U phase of the motor, the second IGBT tube M2 and the fifth IGBT tube M5 are connected in parallel and then connected with the V phase of the motor, and the third IGBT tube M3 and the sixth IGBT tube M6 are connected in parallel and then connected with the W phase of the motor.

3. The detection circuit of direct current variable frequency current according to claim 2, wherein the gate of the first IGBT M1 is connected in parallel with one end of a first resistor R1 and one end of a second resistor R2, the other end of the first resistor R1 is connected with the signal UH, the other end of the second resistor R2 is connected with the emitter of a first IGBT M1, and the emitter of the first IGBT M1 is connected in parallel with the collector of a fourth IGBT M4 and then connected with the U phase of the motor; a gate of the fourth IGBT transistor M4 is connected in parallel with one end of a seventh resistor R7 and one end of an eighth resistor R8, the other end of the seventh resistor R7 is connected with a signal UL, an emitter of the fourth IGBT transistor M4 is connected in series with a twelfth resistor R12 and then connected in parallel with the other end of an eighth resistor R8 and one end of a first capacitor C1, and the other end of the first capacitor C1 is connected with a collector of a first IGBT transistor M1;

the gate of the second IGBT tube M2 is connected in parallel with one end of a third resistor R3 and one end of a fourth resistor R4, the other end of the third resistor R3 is connected with a signal VH, the other end of the fourth resistor R4 is connected with the emitter of the second IGBT tube M2, and the emitter of the second IGBT tube M2 is connected in parallel with the collector of a fifth IGBT tube M5 and then is connected with the V phase of the motor; a gate of the fifth IGBT transistor M5 is connected in parallel with one end of a ninth resistor R9 and one end of a tenth resistor R10, the other end of the ninth resistor R9 is connected with the signal VL, an emitter of the fifth IGBT transistor M5 is connected in series with an eleventh resistor R11 and then connected in parallel with the other end of the tenth resistor R10 and one end of a second capacitor C2, and the other end of the second capacitor C2 is connected with a collector of the second IGBT transistor M2;

a gate of the third IGBT tube M3 is connected in parallel with one end of a fifth resistor R5 and one end of a sixth resistor R6, the other end of the fifth resistor R5 is connected with a signal WH, the other end of the sixth resistor R6 is connected with an emitter of a third IGBT tube M3, and an emitter of the third IGBT tube M3 is connected in parallel with a collector of a sixth IGBT tube M6 and then connected with a W phase of the motor; a gate of the sixth IGBT transistor M6 is connected in parallel with one end of a thirteenth resistor R13 and one end of a fourteenth resistor R14, the other end of the thirteenth resistor R13 is connected with a signal WL, an emitter of the sixth IGBT transistor M6 is connected in parallel with the other end of the fourteenth resistor R14 and one end of a third capacitor C3, and the other end of the third capacitor C3 is connected with a collector of the third IGBT transistor M3;

the collector of the first IGBT M1, the collector of the second IGBT M2, and the collector of the third IGBT M3 are all connected to a power supply, the emitter of the fourth IGBT M4 is connected in series with a twelfth resistor R12, the emitter of the fifth IGBT M5 is connected in series with an eleventh resistor R11, and the emitter of the sixth IGBT M6 is connected in parallel and then connected to one end of a fifteenth resistor R15, and the other end of the fifteenth resistor R15 is grounded.

4. The detection circuit of the direct current variable frequency current according to claim 3, wherein the resistance of the eleventh resistor R11, the resistance of the twelfth resistor R12 and the resistance of the fifteenth resistor R15 are all equal.

5. The detection circuit of direct-current variable-frequency current according to claim 4, wherein the number of the current detection resistors is the same as the number of the current detection circuits (2) and is at least two.

6. The detection circuit of direct current variable frequency current according to claim 5, characterized in that the current detection circuit (2) comprises a signal amplification circuit (21) and a signal raising circuit (22), the signal amplification circuit (21) is connected to two ends of the current detection resistor for amplifying the detected voltage signal, and the signal raising circuit (22) is electrically connected to the signal amplification circuit (21) for raising the detected voltage signal.

7. The detection circuit of a direct current variable frequency current according to claim 6, characterized in that the signal amplification circuit (21) comprises an operational amplifier U1, the port C of the operational amplifier U1 is connected in parallel with one end of a seventeenth resistor R17 and one end of an eighteenth resistor R18, one end of the seventeenth resistor R17 is connected to the SUM CURR terminal of the twelfth resistor R12 or the SUM CURR terminal of the eleventh resistor R11, the other end of the eighteenth resistor R18 is connected with the C _ O port of the operational amplifier U1, the port C + of the operational amplifier U1 is connected with one end of the nineteenth resistor R19 and one end of the twentieth resistor R20 in parallel, the other end of the nineteenth resistor R19 is connected with the IU + CURR end of the twelfth resistor R12 or the IV + CURR end of the eleventh resistor R11, the fourth port of the operational amplifier U1 is connected with a power supply, and the 11 th port of the operational amplifier U1 is connected with the ground.

8. The detection circuit of the direct current variable frequency current according to claim 7, wherein the signal raising circuit (22) comprises a twenty-first resistor R21 and a twenty-second resistor R22, the other end of the twentieth resistor R20 is connected in series with one end of the twenty-first resistor R21 and one end of the twenty-second resistor R22, the other end of the twenty-first resistor R21 is connected with a power supply, and the other end of the twenty-second resistor R22 is connected with the ground.

9. The detection circuit of direct current variable frequency current according to claim 8, wherein the resistance of the seventeenth resistor R17 is equal to the resistance of the nineteenth resistor R19, and the resistance of the eighteenth resistor R18 is equal to the resistance of the twentieth resistor R20.

10. The detection circuit of direct current variable frequency current according to claim 8 or 9, characterized in that the twenty-first resistor R21 and the twenty-second resistor R22 are of the same order of magnitude as the nineteenth resistor R19 and the twentieth resistor R20.

Technical Field

The invention belongs to the technical field of direct current frequency conversion, and particularly relates to a detection circuit for direct current frequency conversion current.

Background

The direct current frequency conversion technology usually adopts an inverter bridge circuit to drive a motor to operate, the voltage at two ends of a current detection resistor is detected to indirectly detect the current so as to sense whether the current in the circuit is overlarge, and if the current is overlarge, the motor is stopped to operate so as to play a role in protection.

The traditional current detection circuit generally amplifies the voltage at two ends of a current detection resistor through an operational amplifier, and an MCU samples and processes an amplified voltage signal, but the voltage direction at two ends of the current detection resistor is changed continuously when a motor runs, namely the voltage direction is sometimes positive and sometimes negative, while the traditional current detection circuit can only detect positive voltage, so that the traditional current detection circuit can only play a role in time-limited detection and cannot play a role in full-time detection; in addition, the traditional full-time current detection is generally realized by adopting a chip, so that the cost is higher, and the difficulty in chip software programming development is higher.

Disclosure of Invention

In order to solve the above problems, the present invention provides a detection circuit for dc variable frequency current, which realizes full-time detection of current in the dc variable frequency circuit by building a peripheral hardware circuit.

The technical scheme adopted by the invention is as follows:

the utility model provides a detection circuitry of direct current frequency conversion electric current, includes motor drive circuit and examines the electric current circuit, the electric connection examines the electric resistance in the motor drive circuit, and examine the external examination electric current circuit that is used for enlargiing, raising the signal in current resistance both ends and detect in order to realize full-time current detection.

Preferably, the motor driving circuit comprises a bridge arm U, a bridge arm V, a bridge arm W and a motor, wherein the bridge arm U comprises a first IGBT tube M1 and a fourth IGBT tube M4, the bridge arm V comprises a second IGBT tube M2 and a fifth IGBT tube M5, the bridge arm W comprises a third IGBT tube M3 and a sixth IGBT tube M6, the first IGBT tube M1 and the fourth IGBT tube M4 are connected in parallel and then connected with the U phase of the motor, the second IGBT tube M2 and the fifth IGBT tube M5 are connected in parallel and then connected with the V phase of the motor, and the third IGBT tube M3 and the sixth IGBT tube M6 are connected in parallel and then connected with the W phase of the motor.

Preferably, the gate of the first IGBT transistor M1 is connected in parallel with one end of a first resistor R1 and one end of a second resistor R2, the other end of the first resistor R1 is connected with the signal UH, the other end of the second resistor R2 is connected with the emitter of the first IGBT transistor M1, and the emitter of the first IGBT transistor M1 is connected in parallel with the collector of the fourth IGBT transistor M4 and then connected with the U phase of the motor; a gate of the fourth IGBT transistor M4 is connected in parallel with one end of a seventh resistor R7 and one end of an eighth resistor R8, the other end of the seventh resistor R7 is connected with a signal UL, an emitter of the fourth IGBT transistor M4 is connected in series with a twelfth resistor R12 and then connected in parallel with the other end of an eighth resistor R8 and one end of a first capacitor C1, and the other end of the first capacitor C1 is connected with a collector of a first IGBT transistor M1;

the gate of the second IGBT tube M2 is connected in parallel with one end of a third resistor R3 and one end of a fourth resistor R4, the other end of the third resistor R3 is connected with a signal VH, the other end of the fourth resistor R4 is connected with the emitter of the second IGBT tube M2, and the emitter of the second IGBT tube M2 is connected in parallel with the collector of a fifth IGBT tube M5 and then is connected with the V phase of the motor; a gate of the fifth IGBT transistor M5 is connected in parallel with one end of a ninth resistor R9 and one end of a tenth resistor R10, the other end of the ninth resistor R9 is connected with the signal VL, an emitter of the fifth IGBT transistor M5 is connected in series with an eleventh resistor R11 and then connected in parallel with the other end of the tenth resistor R10 and one end of a second capacitor C2, and the other end of the second capacitor C2 is connected with a collector of the second IGBT transistor M2;

a gate of the third IGBT tube M3 is connected in parallel with one end of a fifth resistor R5 and one end of a sixth resistor R6, the other end of the fifth resistor R5 is connected with a signal WH, the other end of the sixth resistor R6 is connected with an emitter of a third IGBT tube M3, and an emitter of the third IGBT tube M3 is connected in parallel with a collector of a sixth IGBT tube M6 and then connected with a W phase of the motor; a gate of the sixth IGBT transistor M6 is connected in parallel with one end of a thirteenth resistor R13 and one end of a fourteenth resistor R14, the other end of the thirteenth resistor R13 is connected with a signal WL, an emitter of the sixth IGBT transistor M6 is connected in parallel with the other end of the fourteenth resistor R14 and one end of a third capacitor C3, and the other end of the third capacitor C3 is connected with a collector of the third IGBT transistor M3;

the collector of the first IGBT M1, the collector of the second IGBT M2, and the collector of the third IGBT M3 are all connected to a power supply, the emitter of the fourth IGBT M4 is connected in series with a twelfth resistor R12, the emitter of the fifth IGBT M5 is connected in series with an eleventh resistor R11, and the emitter of the sixth IGBT M6 is connected in parallel and then connected to one end of a fifteenth resistor R15, and the other end of the fifteenth resistor R15 is grounded.

Preferably, the resistance of the eleventh resistor R11, the resistance of the twelfth resistor R12 and the resistance of the fifteenth resistor R15 are all equal.

Preferably, the number of the current detection resistors and the number of the current detection circuits are the same and are at least two.

Preferably, the current detection circuit comprises a signal amplification circuit and a signal raising circuit, the signal amplification circuit is connected to two ends of the current detection resistor for amplifying the detected voltage signal, and the signal raising circuit is electrically connected to the signal amplification circuit for raising the detected voltage signal.

Preferably, the signal amplifying circuit includes an operational amplifier U1, a port C of the operational amplifier U1 is connected in parallel with one end of a seventeenth resistor R17 and one end of an eighteenth resistor R18, one end of the seventeenth resistor R17 is connected to a SUM currr terminal of a twelfth resistor R12 or a SUM currr terminal of an eleventh resistor R11, the other end of the eighteenth resistor R18 is connected to a C _ O port of the operational amplifier U1, a port C + of the operational amplifier U1 is connected in parallel with one end of a nineteenth resistor R19 and one end of a twentieth resistor R20, the other end of the nineteenth resistor R19 is connected to an IU + currr terminal of a twelfth resistor R12 or an IV + currr terminal of an eleventh resistor R11, a fourth port of the operational amplifier U1 is connected to a power supply, and an 11 th port of the operational amplifier U1 is connected to ground.

Preferably, the signal raising circuit comprises a twenty-first resistor R21 and a twenty-second resistor R22, the other end of the twentieth resistor R20 is connected with one end of the twenty-first resistor R21 and one end of the twenty-second resistor R22 in series, the other end of the twenty-first resistor R21 is connected with a power supply, and the other end of the twenty-second resistor R22 is grounded.

Preferably, the resistance value of the seventeenth resistor R17 is equal to that of the nineteenth resistor R19, and the resistance value of the eighteenth resistor R18 is equal to that of the twentieth resistor R20.

Preferably, the twenty-first resistor R21 and the twenty-second resistor R22 are of the same order of magnitude as the nineteenth resistor R19 and the twentieth resistor R20.

Compared with the prior art, the direct-current variable-frequency current detection circuit realizes full-time current detection by electrically connecting the current detection resistor in the motor driving circuit and externally connecting the current detection resistor with the current detection circuit, not only can realize circuit overcurrent protection, but also can detect the current state in real time to meet the high-precision control requirement of the motor; in addition, the current full-time detection replaces a chip implementation mode with a peripheral hardware circuit implementation mode, so that the chip cost is saved, and meanwhile, the software development difficulty is reduced because chip software programming is not needed.

Drawings

Fig. 1 is a circuit diagram of a dc variable frequency motor driving circuit of a dc variable frequency current detection circuit according to an embodiment of the present invention;

fig. 2 is a current detection circuit diagram of a detection circuit for dc variable frequency current according to an embodiment of the present invention;

fig. 3 is a terminal voltage waveform diagram of a detection resistor of a detection circuit for a dc variable current according to an embodiment of the present invention.

Description of the reference numerals

1-motor driving circuit, 2-current detecting circuit, 21-signal amplifying circuit and 22-signal raising circuit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.