CN111969560A - Direct current frequency conversion current loop control circuit - Google Patents

Direct current frequency conversion current loop control circuit Download PDF

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Publication number
CN111969560A
CN111969560A CN202010675034.6A CN202010675034A CN111969560A CN 111969560 A CN111969560 A CN 111969560A CN 202010675034 A CN202010675034 A CN 202010675034A CN 111969560 A CN111969560 A CN 111969560A
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resistor
operational amplifier
signal
twenty
parallel
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罗淦恩
高宁
潘叶江
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Vatti Co Ltd
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Vatti Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
    • H02H7/0833—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors for electric motors with control arrangements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
    • H02H7/085—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load

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Abstract

The invention discloses a direct current variable frequency current loop control circuit, which comprises: the device comprises a signal rectification module for rectifying and collecting the raised terminal voltage of the U, V, W phase current detection resistor of the direct current brushless motor and a signal comparison module for comparing the collected signal with a preset voltage and then controlling the switch of the direct current brushless motor, wherein the signal rectification module is electrically connected with the signal comparison module. According to the direct-current variable-frequency current loop control circuit, the terminal voltage of the phase current detection resistor of the direct-current brushless motor U, V, W is rectified and collected through the signal rectification module, the collected signal is compared with the preset voltage through the signal comparison module, and then the switch of the direct-current brushless motor is controlled, so that hardware overcurrent detection is achieved by building a hardware circuit, the cost is low, the implementation is easy, hardware protection measures are added on the basis of software protection, the product reliability is improved, and extra cost caused by software protection level evaluation is avoided.

Description

Direct current frequency conversion current loop control circuit
Technical Field
The invention belongs to the technical field of direct current frequency conversion, and particularly relates to a direct current frequency conversion current loop control circuit.
Background
The dc frequency conversion technology usually adopts an inverter bridge circuit to drive the motor to operate, wherein the current loop control means that the controller always detects U, V, W phase line currents flowing through the motor, and when the controller detects that a certain phase line current is too large, the driving signal of the motor is stopped, thereby realizing the protection measure of overcurrent shutdown.
At present, an operational amplifier and a comparator are integrated in most of motor control MCU chips, so that the current of three phases of a motor can be detected by a single MCU chip, and overcurrent judgment is carried out, namely, a software scheme is adopted for the current loop control function. However, there are two disadvantages to this pure software protection approach alone: 1. once the MCU chip is easy to lose efficacy due to interference software, and the system lacks the protection of a peripheral hardware circuit, the overcurrent protection is easy to lose efficacy, and potential safety hazards are easy to generate; 2. because the system adopts a software protection mode, under the condition of insufficient hardware protection, the software protection level evaluation of product software needs to be carried out by a certification authority, and the mass production can be carried out only after the evaluation. Based on the above two points, it is necessary to add a hardware overcurrent protection measure which is low in cost and easy to implement to the dc frequency conversion controller.
Disclosure of Invention
In order to solve the problems, the invention provides a direct current variable frequency current loop control circuit, which realizes hardware overcurrent detection by building a hardware circuit, has low cost and is easy to realize, and adds hardware protection measures on the basis of software protection, thereby being beneficial to improving the reliability of products and avoiding extra cost caused by software protection level evaluation.
The technical scheme adopted by the invention is as follows:
a direct-current variable-frequency current loop control circuit comprises a signal rectification module and a signal comparison module, wherein the signal rectification module is used for rectifying and collecting the raised end voltage of a phase current detection resistor of a direct-current brushless motor U, V, W, the signal comparison module is used for comparing the collected signal with a preset voltage and then controlling the switch of the direct-current brushless motor, the signal rectification module is electrically connected with the signal comparison module, and the preset voltage in the signal comparison module is adjustable.
Preferably, the signal rectification module comprises a first operational amplifier U1D, a second operational amplifier U2D and a third operational amplifier U3D, wherein the twelfth pin of the first operational amplifier U1D is connected with a voltage of 1.65V, the eleventh pin of the first operational amplifier U1D is connected with a power supply, the fourth pin of the first operational amplifier U1D is grounded, the thirteenth pin of the first operational amplifier U1D is connected in parallel with one end of a first resistor R1, a second resistor R2 and a third diode D3, the other end of the first resistor R1 is connected with the terminal voltage of a U-phase current detection resistor, the other end of the third diode D3 is connected with the fourteenth pin of the first operational amplifier U1D, the other end of the second resistor R2 is connected in series with a first diode D1 and then is connected with the fourteenth pin of the first operational amplifier U1D, and the first diode 1 outputs a first signal UO 1;
a twelfth pin of the second operational amplifier U2D is connected to a voltage of 1.65V, an eleventh pin of the second operational amplifier U2D is connected to a power supply, a fourth pin of the second operational amplifier U2D is connected to ground, a thirteenth pin of the second operational amplifier U2D is connected in parallel to one end of a third resistor R3, a fourth resistor R4 and one end of a sixth diode D6, the other end of the third resistor R3 is connected to a terminal voltage of a V-phase current-sensing resistor, the other end of the sixth diode D6 is connected to a fourteenth pin of the second operational amplifier U2D, the other end of the fourth resistor R4 is connected in series to a fourth diode D4 and then to a fourteenth pin of the second operational amplifier U2D, and the fourth diode D4 outputs a second signal UO 2;
a twelfth pin of the third operational amplifier U3D is connected to a voltage of 1.65V, an eleventh pin of the third operational amplifier U3D is connected to a power supply, a fourth pin of the third operational amplifier U3D is connected to a ground, a thirteenth pin of the third operational amplifier U3D is connected in parallel to one end of a fifth resistor R5, a sixth resistor R6 and one end of a ninth diode D9, the other end of the fifth resistor R5 is connected to a terminal voltage of a W-phase current detection resistor, the other end of the ninth diode D9 is connected to a fourteenth pin of the third operational amplifier U3D, the other end of the sixth resistor R6 is connected in series to a seventh diode D7 and then to a fourteenth pin of the third operational amplifier U3D, and the seventh diode D7 outputs a third signal UO 3;
the first signal UO1 is connected in series with the second diode D2, the second signal UO2 is connected in series with the fifth diode D5, and the third signal UO3 is connected in series with the eighth diode D8, and then the fourth signal UO4 is output.
Preferably, the signal comparison module includes a fourth operational amplifier U4A, the second pin of the fourth operational amplifier U4A is connected to the collected signal of the signal rectification module, the third pin of the fourth operational amplifier U4A is connected in parallel to one end of a seventh resistor R7 and one end of a ninth resistor R9, the other end of the seventh resistor R7 is grounded, the other end of the ninth resistor R9 is grounded, the fourth pin of the fourth operational amplifier U4A is grounded, the first pin of the fourth operational amplifier U4A is connected in series with a power supply after the eighth resistor R8, the eleventh pin of the fourth operational amplifier U4A is connected to the power supply, and the first pin of the fourth operational amplifier U4A outputs a fifth signal UO 5.
Preferably, the ninth resistor R9 is an adjustable resistor.
Preferably, the resistance value of the first resistor R1 is equal to the resistance value of the second resistor R2, the resistance value of the third resistor R3 is equal to the resistance value of the fourth resistor R4, and the resistance value of the fifth resistor R5 is equal to the resistance value of the sixth resistor R6.
Preferably, the device further comprises a motor driving module and a sampling module for raising the voltage of the phase current detection resistor of the brushless direct current motor U, V, W, wherein the motor driving module is electrically connected with the sampling module, and the sampling module is electrically connected with the signal rectifying module for providing the raised voltage of the phase current detection resistor of the brushless direct current motor U, V, W for the signal rectifying module.
Preferably, the motor driving module 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 tube M1 is connected in parallel with one end of an eleventh resistor R11 and one end of a nineteenth resistor R19, the other end of the eleventh resistor R11 is connected with the signal UH, the other end of the nineteenth resistor R19 is connected with the emitter of the first IGBT tube M1, and the emitter of the first IGBT tube M1 is connected in parallel with the collector of the fourth IGBT tube 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 seventeenth resistor R17 and one end of an eighteenth resistor R18, the other end of the seventeenth resistor R17 is connected with a signal UL, an emitter of the fourth IGBT transistor M4 is connected in series with a nineteenth resistor R19 and then connected in parallel with the other end of the eighteenth resistor R18 and one end of a first capacitor C1, and the other end of the first capacitor C1 is connected with a collector of the first IGBT transistor M1;
a gate of the second IGBT tube M2 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 VH, the other end of the fourteenth resistor R14 is connected with an emitter of the second IGBT tube M2, and an emitter of the second IGBT tube M2 is connected in parallel with a collector of a fifth IGBT tube M5 and then is connected with a V phase of the motor; the gate of the fifth IGBT transistor M5 is connected in parallel with one end of a twentieth resistor R20 and one end of a twenty-first resistor R21, the other end of the twentieth resistor R20 is connected with the signal VL, the emitter of the fifth IGBT transistor M5 is connected in series with a twenty-second resistor R22 and then connected in parallel with the other end of the twenty-first resistor R21 and one end of a second capacitor C2, and the other end of the second capacitor C2 is connected with the collector of the second IGBT transistor M2;
a gate of the third IGBT tube M3 is connected in parallel with one end of a fifteenth resistor R15 and one end of a sixteenth resistor R16, the other end of the fifteenth resistor R15 is connected with a signal WH, the other end of the sixteenth resistor R16 is connected with an emitter of the third IGBT tube M3, and an emitter of the third IGBT tube M3 is connected in parallel with a collector of the sixth IGBT tube M6 and then connected with the W phase of the motor; a gate of the sixth IGBT transistor M6 is connected in parallel with one end of a twenty-third resistor R23 and one end of a twenty-fourth resistor R24, the other end of the twenty-third resistor R23 is connected with a signal WL, an emitter of the sixth IGBT transistor M6 is connected in parallel with the other end of the twenty-fourth resistor R24 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 tube M1, the collector of the second IGBT tube M2 and the collector of the third IGBT tube M3 are all connected with a power supply, after the emitter of the fourth IGBT tube M4 is connected with a nineteenth resistor R19 in series, after the emitter of the fifth IGBT tube M5 is connected with a twenty-second resistor R22 in series and after the emitter of the sixth IGBT tube M6 is connected with the emitter in parallel, one end of a twenty-fifth resistor R25 is connected, and the other end of the twenty-fifth resistor R25 is grounded.
Preferably, the sampling module includes a fifth operational amplifier U5, a port C of the fifth operational amplifier U5 is connected in parallel with one end of a twenty-fifth resistor R25 and one end of a twenty-sixth resistor R26, one end of the twenty-fifth resistor R25 is connected to a SUM CURR terminal of a nineteenth resistor R19 or a SUM CURR terminal of a twenty-second resistor R22 or a SUM CURR terminal of a twenty-fourth resistor R24, the other end of the twenty-sixth resistor R26 is connected to a C _ O port of the fifth operational amplifier U5, a port C + of the fifth operational amplifier U5 is connected in parallel with one end of a twenty-seventh resistor R27 and one end of a twenty-eighth resistor R28, the other end of the twenty-seventh resistor R27 is connected to an IU + CURR terminal of a twelfth resistor R12 or an IV + CURR terminal of an eleventh resistor R11 or an IW + CURR terminal of a twenty-fourth resistor R24, and the fourth port of the fifth operational amplifier U5 is connected to the power supply, the 11 th port of the fifth operational amplifier U5 is grounded; the other end of the twenty-eighth resistor R28 is connected with one end of a twenty-ninth resistor R29 and one end of a thirty-fifth resistor R30 in parallel, the other end of the twenty-ninth resistor R29 is connected with a power supply, and the other end of the thirty-fifth resistor R30 is grounded.
Preferably, the first operational amplifier U1D, the second operational amplifier U2D, the third operational amplifier U3D and the fourth operational amplifier U4A are each of the type GS 8724.
Compared with the prior art, the direct-current variable-frequency current loop control circuit has the advantages that the terminal voltage of the phase current detection resistor of the direct-current brushless motor U, V, W is rectified and collected through the signal rectification module, the collected signal is compared with the preset voltage through the signal comparison module, and then the direct-current brushless motor is controlled to be switched on and off, so that hardware overcurrent detection is realized through building a hardware circuit, the cost is low, the implementation is easy, hardware protection measures are added on the basis of software protection, the product reliability is favorably improved, and extra cost caused by software protection level evaluation is avoided.
Drawings
Fig. 1 is a circuit diagram of a dc variable frequency current loop control circuit according to an embodiment of the present invention;
fig. 2 is a diagram of a terminal voltage waveform of a dc variable-frequency current loop control circuit after passing through a signal rectification module according to an embodiment of the present invention;
fig. 3 is a voltage collection signal U04 at the UVW three-phase current detection end of the dc current loop control circuit according to an embodiment of the present invention;
fig. 4 is a circuit diagram of a motor driving module of a dc variable-frequency current loop control circuit according to an embodiment of the present invention;
fig. 5 is a circuit diagram of a sampling module of a dc variable-frequency current loop control circuit according to an embodiment of the present invention;
fig. 6 is a voltage waveform diagram of a detection resistor of a dc current loop control circuit according to an embodiment of the present invention;
fig. 7 shows that the terminal voltage of the dc variable-frequency current loop control circuit provided in the embodiment of the present invention is raised to about 1.65V by the sampling module.
Description of the reference numerals
The system comprises a signal rectification module 1, a signal comparison module 2, a motor driving module 3 and a sampling module 4.
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.
Examples
The embodiment of the invention provides a direct-current variable-frequency current loop control circuit, which comprises a signal rectification module 1 and a signal comparison module 2, wherein the signal rectification module 1 is used for rectifying and collecting the raised end voltage of a phase current detection resistor of a direct-current brushless motor U, V, W, the signal comparison module 2 is used for comparing the collected signal with a preset voltage and then controlling the switch of the direct-current brushless motor, the signal rectification module 1 is electrically connected with the signal comparison module 2, and the preset voltage in the signal comparison module 2 is adjustable.
Therefore, the terminal voltage of the phase current detection resistor of the direct current brushless motor U, V, W is rectified and collected through the signal rectification module 1, the collected signal is compared with the preset voltage through the signal comparison module 2 to control the switch of the direct current brushless motor, in addition, the preset voltage in the signal comparison module 2 can be adjusted according to actual needs, thereby realizing hardware overcurrent detection by building a hardware circuit, the cost is low, the realization is easy, on the basis of software protection, hardware protection measures are added, the product reliability is favorably improved, and extra expenses caused by software protection level evaluation are avoided.
The signal rectification module 1 comprises a first operational amplifier U1D, a second operational amplifier U2D and a third operational amplifier U3D, wherein a voltage of 1.65V is connected to a twelfth pin of the first operational amplifier U1D, an eleventh pin of the first operational amplifier U1D is connected to a power supply, a fourth pin of the first operational amplifier U1D is grounded, a thirteenth pin of the first operational amplifier U1D is connected in parallel with one end of a first resistor R1, a second resistor R2 and a third diode D3, the other end of the first resistor R1 is connected to a U-phase current detection resistor, the other end of the third diode D3 is connected to a fourteenth pin of the first operational amplifier U1D, the other end of the second resistor R2 is connected in series with a first diode D1 and then is connected to a fourteenth pin of the first operational amplifier U1D, and the first diode D1 outputs a first signal UO 1;
a twelfth pin of the second operational amplifier U2D is connected to a voltage of 1.65V, an eleventh pin of the second operational amplifier U2D is connected to a power supply, a fourth pin of the second operational amplifier U2D is connected to ground, a thirteenth pin of the second operational amplifier U2D is connected in parallel to one end of a third resistor R3, a fourth resistor R4 and one end of a sixth diode D6, the other end of the third resistor R3 is connected to a terminal voltage of a V-phase current-sensing resistor, the other end of the sixth diode D6 is connected to a fourteenth pin of the second operational amplifier U2D, the other end of the fourth resistor R4 is connected in series to a fourth diode D4 and then to a fourteenth pin of the second operational amplifier U2D, and the fourth diode D4 outputs a second signal UO 2;
a twelfth pin of the third operational amplifier U3D is connected to a voltage of 1.65V, an eleventh pin of the third operational amplifier U3D is connected to a power supply, a fourth pin of the third operational amplifier U3D is connected to a ground, a thirteenth pin of the third operational amplifier U3D is connected in parallel to one end of a fifth resistor R5, a sixth resistor R6 and one end of a ninth diode D9, the other end of the fifth resistor R5 is connected to a terminal voltage of a W-phase current detection resistor, the other end of the ninth diode D9 is connected to a fourteenth pin of the third operational amplifier U3D, the other end of the sixth resistor R6 is connected in series to a seventh diode D7 and then to a fourteenth pin of the third operational amplifier U3D, and the seventh diode D7 outputs a third signal UO 3;
the first signal UO1 is connected in series with the second diode D2, the second signal UO2 is connected in series with the fifth diode D5, and the third signal UO3 is connected in series with the eighth diode D8, and then the fourth signal UO4 is output.
After the voltage of the current detection resistor of the U, V, W phase is raised to the vicinity of 1.65V by the sampling module 4, the voltage first enters the signal rectification module 1, and is rectified by the reverse amplification circuit composed of three operational amplifiers (i.e., the first operational amplifier U1D, the second operational amplifier U2D, the third operational amplifier U3D and the fourth operational amplifier U4A) arranged in parallel on the left side, so that the portion of the voltage of the current detection resistor lower than 1.65V is inverted upwards.
Taking the terminal voltage of the U-phase as an example, the D + port of the first operational amplifier U1D is connected to 1.65V, D-is connected to the terminal voltage of the U-phase, D _ O is the voltage output terminal, R1 ═ R2 ═ 20K (i.e., the amplification factor is 1), and the diodes D1 and D3 provide a path when UD-is higher than 1.65V, as can be known from the principle of the reverse amplifier:
a. when UD-is higher than 1.65V, the current path is two paths of (1) number line, UD _ O ═ UD-;
b. when UD-is lower than 1.65V, the current path is a path of the wire with the number (2), and UD _ O is 1.65V + (1.65V-UD-);
as shown in fig. 2, for the comparison of waveforms before and after the voltage across the current detecting resistor passes through the rectifier circuit, it can be seen that the portion of the voltage across the rectifier circuit, which is lower than 1.65V, is inverted upward.
The signal comparison module 2 comprises a fourth operational amplifier U4A, a second pin of the fourth operational amplifier U4A is connected with a collected signal of the signal rectification module 1, a third pin of the fourth operational amplifier U4A is connected with one end of a seventh resistor R7 and one end of a ninth resistor R9 in parallel, the other end of the seventh resistor R7 is grounded, the other end of the ninth resistor R9 is grounded, a fourth pin of the fourth operational amplifier U4A is grounded, a first pin of the fourth operational amplifier U4A is connected with a power supply after being connected with an eighth resistor R8 in series, an eleventh pin of the fourth operational amplifier U4A is connected with the power supply, and the first pin of the fourth operational amplifier U4A outputs a fifth signal UO 5.
Therefore, voltage of current detection resistors of U, V, W three phases is rectified to obtain signals UO1, UO2 and UO3, and then is converged into a signal UO4 through diodes D2, D5 and D8, wherein the diodes are arranged to isolate the signal UO4 by utilizing unidirectional conductivity of the diodes so as to avoid influencing source signals UO1, UO2 and UO 3.
As shown in fig. 3, it is a UO4 signal, and at this time, the current threshold value can be set to 2V by the signal comparing module 2, and when the voltage at the current detection end of U, V, W three phases is greater than 2V, the system can be controlled to shut down the motor.
The ninth resistor R9 is an adjustable resistor.
Thus, the comparison voltage may be output by a circuit composed of a fixed resistor R7(R7 ═ 1K) and an adjustable resistor R9 (here, the comparison voltage (preset voltage) ═ 2V may be achieved by adjusting R9 ═ 1.54K). When the UO4 is higher than 2V (preset voltage), the comparison value UO5 is 3.3V, and when the UO4 is lower than 2V (preset voltage), the comparison value UO5 is 0V, and the comparison voltage (preset voltage) can be adjusted and changed by adjusting the resistance value of the adjustable resistor R9 according to actual requirements. Therefore, the motor can be shut down when the current overcurrent is detected through the switching signal UO5, and the motor still normally operates when the current overcurrent does not exist, namely amplitude-limiting current loop control is realized.
The resistance of the first resistor R1 is equal to the resistance of the second resistor R2, the resistance of the third resistor R3 is equal to the resistance of the fourth resistor R4, and the resistance of the fifth resistor R5 is equal to the resistance of the sixth resistor R6.
In this way, by setting the resistance of the first resistor R1 equal to the resistance of the second resistor R2, the resistance of the third resistor R3 equal to the resistance of the fourth resistor R4, and the resistance of the fifth resistor R5 equal to the resistance of the sixth resistor R6, the amplification factors are all 1.
The device is characterized by further comprising a motor driving module 3 and a sampling module 4 used for raising the voltage of the phase current detection resistor of the brushless direct current motor U, V, W, wherein the motor driving module 3 is electrically connected with the sampling module 4, and the sampling module 4 is electrically connected with the signal rectification module 1 and used for providing the raised voltage of the phase current detection resistor of the brushless direct current motor U, V, W for the signal rectification module 1.
Therefore, the current detection resistor is electrically connected in the motor driving module 3, the sampling modules 4 are externally connected to two ends of the current detection resistor, the sampling modules 4 provide the raised end voltage of the U, V, W-phase current detection resistor for the signal rectification module 1, and the voltage signal of the current detection resistor is raised to be near 1.65V after passing through the sampling modules 4, so that the MCU can detect the voltage within the range of 0-3.3V.
As shown in fig. 4, the motor drive module 3 includes a bridge arm U, a bridge arm V, a bridge arm W and a motor, where the bridge arm U includes a first IGBT tube M1 and a fourth IGBT tube M4, the bridge arm V includes a second IGBT tube M2 and a fifth IGBT tube M5, the bridge arm W includes 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 to the U phase of the motor, the second IGBT tube M2 and the fifth IGBT tube M5 are connected in parallel and then connected to 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 to the W phase of the motor.
Thus, the bridge arm U, the bridge arm V and the bridge arm W form a driving circuit to drive the motor to rotate, and when the U phase and the V phase of the motor are conducted, according to a conventional control method, only M1 and M5 in 6 IGBT tubes M1, M2, M3, M4, M5 and M6 are in a control state, M1 is an upper tube, a control signal of the upper tube is PWM, M5 is a lower tube, and a control signal of the lower tube is high level.
a. When the PWM signal of M1 is at high level and the control signal of M5 is at high level, M1 and M5 are both turned on, and the current direction is ABCDEFGHIA;
b. when the PWM signal of M1 is at low level and the control signal of M5 is at high level, M1 is turned off, M5 is turned on, and since the motor is an inductive load, the current freewheels through the body diode of M4, and the current direction is BCDEFGHIJB;
according to the above current direction analysis, with IU + _ CURR of the current detection resistor R19 as the positive terminal and SUM _ CURR as the negative terminal, it can be known that the voltage across R19 is either 0V or negative. The positive terminal is IV + _ CURR of the current detection resistor R20, the negative terminal is SUM _ CURR, and the voltage across R22 is positive.
As shown in fig. 6, in order to detect the voltage waveform diagram of the resistor, the above mentioned is the case where two phases are conducted, since the motor needs to continuously switch the conducted phases during the operation and the motor can adjust the speed, so in summary, the voltage conditions at two ends of each current detecting resistor during the operation of the motor are as follows: sometimes positive and sometimes negative, and the voltage amplitude value is varied.
The gate of the first IGBT tube M1 is connected in parallel with one end of an eleventh resistor R11 and one end of a nineteenth resistor R19, the other end of the eleventh resistor R11 is connected with a signal UH, the other end of the nineteenth resistor R19 is connected with the emitter of the first IGBT tube M1, and the emitter of the first IGBT tube M1 is connected in parallel with the collector of the fourth IGBT tube 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 seventeenth resistor R17 and one end of an eighteenth resistor R18, the other end of the seventeenth resistor R17 is connected with a signal UL, an emitter of the fourth IGBT transistor M4 is connected in series with a nineteenth resistor R19 and then connected in parallel with the other end of the eighteenth resistor R18 and one end of a first capacitor C1, and the other end of the first capacitor C1 is connected with a collector of the first IGBT transistor M1;
a gate of the second IGBT tube M2 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 VH, the other end of the fourteenth resistor R14 is connected with an emitter of the second IGBT tube M2, and an emitter of the second IGBT tube M2 is connected in parallel with a collector of a fifth IGBT tube M5 and then is connected with a V phase of the motor; the gate of the fifth IGBT transistor M5 is connected in parallel with one end of a twentieth resistor R20 and one end of a twenty-first resistor R21, the other end of the twentieth resistor R20 is connected with the signal VL, the emitter of the fifth IGBT transistor M5 is connected in series with a twenty-second resistor R22 and then connected in parallel with the other end of the twenty-first resistor R21 and one end of a second capacitor C2, and the other end of the second capacitor C2 is connected with the collector of the second IGBT transistor M2;
a gate of the third IGBT tube M3 is connected in parallel with one end of a fifteenth resistor R15 and one end of a sixteenth resistor R16, the other end of the fifteenth resistor R15 is connected with a signal WH, the other end of the sixteenth resistor R16 is connected with an emitter of the third IGBT tube M3, and an emitter of the third IGBT tube M3 is connected in parallel with a collector of the sixth IGBT tube M6 and then connected with the W phase of the motor; a gate of the sixth IGBT transistor M6 is connected in parallel with one end of a twenty-third resistor R23 and one end of a twenty-fourth resistor R24, the other end of the twenty-third resistor R23 is connected with a signal WL, an emitter of the sixth IGBT transistor M6 is connected in parallel with the other end of the twenty-fourth resistor R24 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 tube M1, the collector of the second IGBT tube M2 and the collector of the third IGBT tube M3 are all connected with a power supply, after the emitter of the fourth IGBT tube M4 is connected with a nineteenth resistor R19 in series, after the emitter of the fifth IGBT tube M5 is connected with a twenty-second resistor R22 in series and after the emitter of the sixth IGBT tube M6 is connected with the emitter in parallel, one end of a twenty-fifth resistor R25 is connected, and the other end of the twenty-fifth resistor R25 is grounded.
In this way, the motor driving circuit is composed of the first IGBT M1, the second IGBT M2, the third IGBT M3, the fourth IGBT M4, the fifth IGBT M5 and the sixth IGBT M6, and the nineteenth resistor R19 (U-phase current detection resistor), the twenty-second resistor R22 (V-phase current detection resistor) and the twenty-fourth resistor R24 (W-phase current detection resistor) are electrically connected to the motor driving circuit, so that the sampling module can amplify and boost the voltages at two ends of the nineteenth resistor R19, the twenty-second resistor R22 and the twenty-fourth resistor R24.
As shown in fig. 5, the sampling module 4 includes a fifth operational amplifier U5, a port C of the fifth operational amplifier U5 is connected in parallel with one end of a twenty-fifth resistor R25 and one end of a twenty-sixth resistor R26, one end of the twenty-fifth resistor R25 is connected to a SUM currr terminal of a nineteenth resistor R19 or a SUM currr terminal of a twenty-second resistor R22 or a SUM currr terminal of a twenty-fourth resistor R24, the other end of the twenty-sixth resistor R26 is connected to a C _ O port of a fifth operational amplifier U5, a port C + of the fifth operational amplifier U5 is connected in parallel with one end of a twenty-seventh resistor R27 and one end of a twenty-eighth resistor R28, the other end of the twenty-seventh resistor R27 is connected to an IU + currr terminal of a twelfth resistor R12 or an IV + currr terminal of an eleventh resistor R11 or an IW + currr 24, and the fourth port of the fifth operational amplifier U5 is connected to a source operational amplifier U5, the 11 th port of the fifth operational amplifier U5 is grounded; the other end of the twenty-eighth resistor R28 is connected with one end of a twenty-ninth resistor R29 and one end of a thirty-fifth resistor R30 in parallel, the other end of the twenty-ninth resistor R29 is connected with a power supply, and the other end of the thirty-fifth resistor R30 is grounded.
Thus, as shown in fig. 7, U, V, W phase current detection resistor terminal voltage (IU + _ CURR/IV + _ CURR/IW + _ CURR) is raised to near 1.65V by the sampling module 4, so as to provide the signal rectification module 1 with the raised terminal voltage of the phase current detection resistor of the dc brushless motor U, V, W.
The first operational amplifier U1D, the second operational amplifier U2D, the third operational amplifier U3D and the fourth operational amplifier U4A are all GS8724 in model number.
In this way, the first operational amplifier U1D, the second operational amplifier U2D, and the third operational amplifier U3D form an inverting amplifier circuit, and the fourth operational amplifier U4A forms a signal comparison module.
According to the direct-current variable-frequency current loop control circuit, the terminal voltage of the phase current detection resistor of the direct-current brushless motor U, V, W is rectified and collected through the signal rectification module, the collected signal is compared with the preset voltage through the signal comparison module, and then the switch of the direct-current brushless motor is controlled, so that hardware overcurrent detection is achieved by building a hardware circuit, the cost is low, the implementation is easy, hardware protection measures are added on the basis of software protection, the product reliability is improved, and extra cost caused by software protection level evaluation is avoided.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. The direct-current variable-frequency current loop control circuit is characterized by comprising a signal rectification module (1) for rectifying and collecting the raised terminal voltage of a phase current detection resistor of a direct-current brushless motor U, V, W and a signal comparison module (2) for comparing the collected signal with a preset voltage and then controlling the switch of the direct-current brushless motor, wherein the signal rectification module (1) is electrically connected with the signal comparison module (2), and the preset voltage in the signal comparison module (2) is adjustable.
2. The DC current loop control circuit according to claim 1, wherein the signal rectification module (1) comprises a first operational amplifier U1D, a second operational amplifier U2D and a third operational amplifier U3D, the twelfth pin of the first operational amplifier U1D is connected with a voltage of 1.65V, the eleventh pin of the first operational amplifier U1D is connected with a power supply, the fourth pin of the first operational amplifier U1D is connected with ground, the thirteenth pin of the first operational amplifier U1D is connected with one end of a first resistor R1, a second resistor R2 and a third diode D3 in parallel, the other end of the first resistor R1 is connected with the terminal voltage of a U-phase current detection resistor, the other end of the third diode D3 is connected with the fourteenth pin of the first operational amplifier U1D, the other end of the second resistor R2 is connected with the fourteenth pin of the first operational amplifier U1D after being connected with the first diode D1 in series, the output of the first diode D1 is a first signal UO 1;
a twelfth pin of the second operational amplifier U2D is connected to a voltage of 1.65V, an eleventh pin of the second operational amplifier U2D is connected to a power supply, a fourth pin of the second operational amplifier U2D is connected to ground, a thirteenth pin of the second operational amplifier U2D is connected in parallel to one end of a third resistor R3, a fourth resistor R4 and one end of a sixth diode D6, the other end of the third resistor R3 is connected to a terminal voltage of a V-phase current-sensing resistor, the other end of the sixth diode D6 is connected to a fourteenth pin of the second operational amplifier U2D, the other end of the fourth resistor R4 is connected in series to a fourth diode D4 and then to a fourteenth pin of the second operational amplifier U2D, and the fourth diode D4 outputs a second signal UO 2;
a twelfth pin of the third operational amplifier U3D is connected to a voltage of 1.65V, an eleventh pin of the third operational amplifier U3D is connected to a power supply, a fourth pin of the third operational amplifier U3D is connected to a ground, a thirteenth pin of the third operational amplifier U3D is connected in parallel to one end of a fifth resistor R5, a sixth resistor R6 and one end of a ninth diode D9, the other end of the fifth resistor R5 is connected to a terminal voltage of a W-phase current detection resistor, the other end of the ninth diode D9 is connected to a fourteenth pin of the third operational amplifier U3D, the other end of the sixth resistor R6 is connected in series to a seventh diode D7 and then to a fourteenth pin of the third operational amplifier U3D, and the seventh diode D7 outputs a third signal UO 3;
the first signal UO1 is connected in series with the second diode D2, the second signal UO2 is connected in series with the fifth diode D5, and the third signal UO3 is connected in series with the eighth diode D8, and then the fourth signal UO4 is output.
3. The direct-current variable-frequency current loop control circuit according to claim 2, wherein the signal comparison module (2) comprises a fourth operational amplifier U4A, a second pin of the fourth operational amplifier U4A is connected to the collected signal of the signal rectification module (1), a third pin of the fourth operational amplifier U4A is connected in parallel with one end of a seventh resistor R7 and one end of a ninth resistor R9, the other end of the seventh resistor R7 is grounded, the other end of the ninth resistor R9 is grounded, a fourth pin of the fourth operational amplifier U4A is grounded, a first pin of the fourth operational amplifier U4A is connected in series with an eighth resistor R8 and then is connected to a power supply, an eleventh pin of the fourth operational amplifier U4A is connected to the power supply, and a first pin of the fourth operational amplifier U4A outputs a fifth signal UO 5.
4. The dc variable frequency current loop control circuit of claim 3, wherein said ninth resistor R9 is an adjustable resistor.
5. The DC variable frequency current loop control circuit according to claim 4, wherein the resistance of the first resistor R1 is equal to the resistance of the second resistor R2, the resistance of the third resistor R3 is equal to the resistance of the fourth resistor R4, and the resistance of the fifth resistor R5 is equal to the resistance of the sixth resistor R6.
6. The direct current variable frequency current loop control circuit according to any one of claims 1-5, further comprising a motor driving module (3) and a sampling module (4) for raising a voltage of a phase current detection resistor of the brushless direct current motor U, V, W, wherein the motor driving module (3) is electrically connected with the sampling module (4), and the sampling module (4) is electrically connected with the signal rectifying module (1) for providing the signal rectifying module (1) with the raised voltage of the phase current detection resistor of the brushless direct current motor U, V, W.
7. The direct-current variable-frequency current loop control circuit according to claim 6, wherein the motor drive module (3) 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 a U phase of the motor, the second IGBT tube M2 and the fifth IGBT tube M5 are connected in parallel and then connected with a 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 a W phase of the motor.
8. The DC variable-frequency current loop control circuit according to claim 7, wherein the gate of the first IGBT transistor M1 is connected in parallel with one end of an eleventh resistor R11 and one end of a nineteenth resistor R19, the other end of the eleventh resistor R11 is connected with the signal UH, the other end of the nineteenth resistor R19 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 seventeenth resistor R17 and one end of an eighteenth resistor R18, the other end of the seventeenth resistor R17 is connected with a signal UL, an emitter of the fourth IGBT transistor M4 is connected in series with a nineteenth resistor R19 and then connected in parallel with the other end of the eighteenth resistor R18 and one end of a first capacitor C1, and the other end of the first capacitor C1 is connected with a collector of the first IGBT transistor M1;
a gate of the second IGBT tube M2 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 VH, the other end of the fourteenth resistor R14 is connected with an emitter of the second IGBT tube M2, and an emitter of the second IGBT tube M2 is connected in parallel with a collector of a fifth IGBT tube M5 and then is connected with a V phase of the motor; the gate of the fifth IGBT transistor M5 is connected in parallel with one end of a twentieth resistor R20 and one end of a twenty-first resistor R21, the other end of the twentieth resistor R20 is connected with the signal VL, the emitter of the fifth IGBT transistor M5 is connected in series with a twenty-second resistor R22 and then connected in parallel with the other end of the twenty-first resistor R21 and one end of a second capacitor C2, and the other end of the second capacitor C2 is connected with the collector of the second IGBT transistor M2;
a gate of the third IGBT tube M3 is connected in parallel with one end of a fifteenth resistor R15 and one end of a sixteenth resistor R16, the other end of the fifteenth resistor R15 is connected with a signal WH, the other end of the sixteenth resistor R16 is connected with an emitter of the third IGBT tube M3, and an emitter of the third IGBT tube M3 is connected in parallel with a collector of the sixth IGBT tube M6 and then connected with the W phase of the motor; a gate of the sixth IGBT transistor M6 is connected in parallel with one end of a twenty-third resistor R23 and one end of a twenty-fourth resistor R24, the other end of the twenty-third resistor R23 is connected with a signal WL, an emitter of the sixth IGBT transistor M6 is connected in parallel with the other end of the twenty-fourth resistor R24 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 tube M1, the collector of the second IGBT tube M2 and the collector of the third IGBT tube M3 are all connected with a power supply, after the emitter of the fourth IGBT tube M4 is connected with a nineteenth resistor R19 in series, after the emitter of the fifth IGBT tube M5 is connected with a twenty-second resistor R22 in series and after the emitter of the sixth IGBT tube M6 is connected with the emitter in parallel, one end of a twenty-fifth resistor R25 is connected, and the other end of the twenty-fifth resistor R25 is grounded.
9. The direct current variable frequency current loop control circuit according to claim 8, wherein the sampling module (4) comprises a fifth operational amplifier U5, the port C of the fifth operational amplifier U5 is connected in parallel with one end of a twenty-fifth resistor R25 and one end of a twenty-sixth resistor R26, one end of the twenty-fifth resistor R25 is connected with the SUM CURR terminal of a nineteenth resistor R19 or the SUM CURR terminal of a twenty-second resistor R22 or the SUM CURR terminal of a twenty-fourth resistor R24, the other end of the twenty-sixth resistor R26 is connected with the C _ O port of a fifth operational amplifier U5, the port C + of the fifth operational amplifier U5 is connected in parallel with one end of a twenty-seventh resistor R27 and one end of a twenty-eighth resistor R28, the other end of the twenty-seventh resistor R27 is connected with the IU + CURR terminal of a twelfth resistor R12 or the IV + CURR terminal of an eleventh resistor R11 or the twenty-fourth resistor IW 24, the fourth port of the fifth operational amplifier U5 is connected with a power supply, and the 11 th port of the fifth operational amplifier U5 is connected with the ground; the other end of the twenty-eighth resistor R28 is connected with one end of a twenty-ninth resistor R29 and one end of a thirty-fifth resistor R30 in parallel, the other end of the twenty-ninth resistor R29 is connected with a power supply, and the other end of the thirty-fifth resistor R30 is grounded.
10. The DC variable frequency current loop control circuit of claim 9, wherein the first operational amplifier U1D, the second operational amplifier U2D, the third operational amplifier U3D and the fourth operational amplifier U4A are all GS8724 in model number.
CN202010675034.6A 2020-07-14 2020-07-14 Direct current frequency conversion current loop control circuit Pending CN111969560A (en)

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Application publication date: 20201120