Control circuit of servo motor

Abstract

The utility model relates to the technical field of servo motor band-type brakes, and relates to a control circuit of a servo motor. According to the circuit, a band-type brake port circuit is connected with a servo motor and used for controlling band-type brake of the servo motor according to a control signal; the driving circuit is connected with the band-type brake port circuit and is used for sending a control signal to the band-type brake port circuit; the input end of the under-voltage and overvoltage protection circuit is connected with a power supply of the servo motor through the band-type brake port circuit, and the output end of the under-voltage and overvoltage protection circuit is connected with the driving circuit; when the input voltage of the power supply is out of a preset working voltage range, the under-voltage and over-voltage protection circuit is used for cutting off the input of the power supply, so that the band-type brake port circuit cannot control the band-type brake of the servo motor, and under-voltage protection or over-voltage protection of the servo motor is realized. Once the input voltage of the power supply in the circuit exceeds a safety range, the protection circuit can automatically cut off the power supply to prevent the servo motor from being damaged by abnormal voltage, so that the safety and the stability of the whole system are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of servo motor brake technology, and further relates to a control circuit of a servo motor. BACKGROUND

[0002] The servo brake system is a key component in the field of industrial automation, and its core function is to achieve precise brake operation through servo motor control to ensure the safe braking and stable operation of the system. The reliable operation of the servo motor is crucial to the performance of the entire system, and the stability of the power supply voltage directly affects the performance and life of the motor. In the prior art, abnormal fluctuations in voltage, such as overvoltage or undervoltage, can cause damage to the servo motor and other problems, thereby affecting the safety and stability of the entire system. CONTENT OF THE UTILITY MODEL

[0003] To solve the above technical problems, the present application provides a control circuit of a servo motor, which can prevent voltage abnormalities from damaging the servo motor and thereby improve the safety and stability of the entire system.

[0004] In a first aspect, the present application provides a control circuit of a servo motor, comprising: a brake port circuit connected to the servo motor, for controlling the servo motor brake according to a control signal; a drive circuit connected to the brake port circuit, for sending the control signal to the brake port circuit; an overvoltage and undervoltage protection circuit, the input end of the overvoltage and undervoltage protection circuit is connected to the power supply of the servo motor through the brake port circuit, and the output end of the overvoltage and undervoltage protection circuit is connected to the drive circuit; when the input voltage of the power supply is outside the preset working voltage range, the overvoltage and undervoltage protection circuit is used to cut off the input of the power supply, so that the brake port circuit cannot control the servo motor brake, realizing the overvoltage and undervoltage protection of the servo motor.

[0005] The above control circuit of the servo motor, the drive circuit is directly connected to the servo motor through the brake port circuit, so that the brake port circuit effectively controls the servo motor brake according to the control signal. The introduction of the overvoltage and undervoltage protection circuit ensures that the system operates within the preset working voltage range by monitoring the input voltage of the power supply. Once the input voltage is outside the preset working voltage range, the overvoltage and undervoltage protection circuit will automatically cut off the power supply to prevent voltage abnormalities from damaging the servo motor, realizing the overvoltage and undervoltage protection of the servo motor, and thereby improving the safety and stability of the entire system.

[0006] In one implementation, it further comprises: a micro control unit connected to the drive circuit, for sending the control signal to the drive circuit; a detection circuit connected to the drive circuit and the micro control unit respectively, for detecting the working voltage across the servo motor and feeding back the working state of the servo motor to the micro control unit based on the working voltage.

[0007] The control circuit of the above servo motor realizes precise control of the brake motor through the connection of the micro control unit and the drive circuit. The micro control unit is responsible for sending control signals to the drive circuit, thereby controlling the start and stop of the brake motor. The detection circuit further enhances the reliability of the system, which is not only connected to the drive circuit, but also connected to the micro control unit, and detects the working voltage of the servo motor in real time. Based on these detected working voltages, the detection circuit feeds back the working state of the servo motor to the micro control unit, ensuring that the system can respond in time when the voltage is abnormal, preventing damage to the motor.

[0008] In one implementation, the under-voltage and over-voltage protection circuit includes an over-voltage protection circuit and an under-voltage protection circuit, the over-voltage protection circuit includes: a first resistor, a second resistor; a first transistor, the base of the first transistor is connected to the first resistor and the second resistor respectively, the collector of the first transistor is connected to the gate of a first MOS tube in the under-voltage protection circuit, and the emitter of the first transistor is connected to the source of the first MOS tube; a first capacitor, the first capacitor is connected to the first resistor in parallel, a first diode, the cathode of the first diode is connected to the second resistor, and the anode of the first diode is grounded.

[0009] In one implementation, the under-voltage protection circuit includes: a fourth resistor; a third resistor, one end of the third resistor is connected to the gate of the first MOS tube, and the other end is connected to the emitter of the first transistor; a second diode, the cathode of the second diode is connected to the gate of the first MOS tube through the fourth resistor, and the anode of the second diode is grounded; the drain of the first MOS tube is connected to the positive terminal of the drive power supply of the servo motor.

[0010] The control circuit of the above servo motor significantly improves the safety and reliability of the system by integrating the over-voltage protection circuit and the under-voltage protection circuit. The over-voltage protection circuit is composed of a first resistor, a second resistor, a first diode, a first capacitor, and a first transistor. When the input voltage exceeds the preset working voltage range, the over-voltage protection circuit responds quickly by turning on the first transistor to cut off the first MOS tube, thereby preventing current from flowing to the servo motor and avoiding damage to the servo motor caused by over-voltage. This realizes over-voltage protection of the servo motor and improves the safety and stability of the entire system. The under-voltage protection circuit is composed of a third resistor, a fourth resistor, and a second diode. When the input voltage is lower than the working voltage range, the under-voltage protection circuit works to ensure that the first MOS tube is cut off under under-voltage conditions, preventing damage caused by running the servo motor under under-voltage. This realizes under-voltage protection of the servo motor and further improves the safety and stability of the entire system.

[0011] In one implementation, the under-voltage over-voltage protection circuit further includes: a fuse; a third diode, an anode of the third diode is connected to the power supply, and a cathode of the third diode is connected to the first resistor through the fuse; and a first TVS tube, one end of the first TVS tube is connected to the power supply, and the other end of the first TVS tube is grounded.

[0012] In one implementation, the driving circuit includes: a sixth resistor; a push-pull circuit, the push-pull circuit is connected to the servo motor and is used for controlling the servo motor to brake; a first optocoupler, a first input end of the first optocoupler is connected to an output pin of the micro control unit through the sixth resistor, a first output end of the first optocoupler is connected to the servo motor, and a second output end of the first optocoupler is connected to the push-pull circuit.

[0013] In one implementation, the push-pull circuit includes: a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a second transistor, a third transistor, a second MOS tube and a fourth diode; a base of the second transistor is connected to the seventh resistor, a collector of the second transistor is connected to the second output end, and an emitter of the second transistor is connected to the eighth resistor; a base of the third transistor is connected to the ninth resistor, a collector of the third transistor is grounded, and an emitter of the third transistor is connected to the eighth resistor; one end of the tenth resistor is connected to the eighth resistor, and the other end of the tenth resistor is grounded; one end of the eleventh resistor is connected to the second output end, and the other end of the eleventh resistor is grounded; a gate of the second MOS tube is connected to the eighth resistor, a source of the second MOS tube is grounded, and a drain of the second MOS tube is connected to the servo motor through a negative end of the driving power supply of the servo motor; a cathode of the fourth diode is connected to the eighth resistor, and an anode of the fourth diode is grounded.

[0014] In one implementation, the driving circuit further includes: a twelfth resistor, one end of the twelfth resistor is connected to the sixth resistor, and the other end of the twelfth resistor is grounded; a second capacitor, one end of the second capacitor is connected to the sixth resistor, and the other end of the second capacitor is grounded; and a fifth diode, a cathode of the fifth diode is connected to the servo motor, and an anode of the fifth diode is connected to the servo motor through the negative end of the driving power supply.

[0015] In one implementation, the detection circuit includes: a second optocoupler, a first input end of the second optocoupler is connected to a positive end of the driving power supply of the servo motor through a thirteenth resistor, a second input end of the second optocoupler is connected to a negative end of the driving power supply, a first output end of the second optocoupler is connected to the first power supply through a fourteenth resistor, and a second output end of the second optocoupler is grounded.

[0016] In one implementation, the detection circuit further includes: a fifteenth resistor, one end of the fifteenth resistor is connected to the thirteenth resistor, and the other end of the fifteenth resistor is connected to the negative end of the driving power supply; a third capacitor, the third capacitor is connected to the fifteenth resistor in parallel; and a sixteenth resistor, one end of the sixteenth resistor is connected to the first output end of the second optocoupler, and the other end of the sixteenth resistor is connected to the fourth capacitor and the micro control unit respectively.

[0017] Compared with the prior art, the utility model has the following beneficial effects:

[0018] The drive circuit is directly connected with the servo motor through the brake port circuit, so that the brake port circuit effectively controls the servo motor brake according to the control signal. The introduction of the under-voltage and over-voltage protection circuit monitors the input voltage of the power supply, ensures that the system operates within the preset working voltage range, and automatically cuts off the power supply when the input voltage is outside the preset working voltage range, preventing voltage abnormalities from damaging the servo motor, realizing under-voltage protection or over-voltage protection of the servo motor, and further improving the safety and stability of the entire system. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above characteristics, technical features, advantages and implementation modes of the utility model will be further described in a clear and understandable manner in combination with the preferred embodiments and the accompanying drawings.

[0020] Figure 1 A structure diagram of a control circuit of a servo motor provided by an embodiment of the application is shown;

[0021] Figure 2 A circuit diagram of an under-voltage and over-voltage protection circuit provided by an embodiment of the application is shown;

[0022] Figure 3 A circuit diagram of a drive circuit provided by an embodiment of the application is shown;

[0023] Figure 4 A circuit diagram of a detection circuit provided by an embodiment of the application is shown. DETAILED DESCRIPTION

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the specific implementation modes of the utility model will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can also be obtained.

[0025] In order to make the drawing simple, only the parts related to the utility model are shown in each drawing, and they do not represent the actual structure of the product. In addition, in order to make the drawing simple and easy to understand, in some drawings, only one of the components with the same structure or function is shown, or only one of them is marked. In this paper, "one" not only means "only one", but also means "more than one".

[0026] It should be further understood that the term "and / or" used in the description and claims of the application herein is used to mean any one and / or all possible combinations of one or more of the associated listed items.

[0027] In this article, it should be pointed out that unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or internal communication of two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0028] In addition, in the description of the application, the terms "first", "second" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0029] It should be pointed out that the above embodiments can be freely combined according to the needs. The above is only the preferred embodiment of the utility model, and it should be pointed out that for ordinary skilled in the art, without departing from the principle of the utility model, some improvements and refinements can be made, which should be regarded as the protection scope of the utility model.

[0030] The servo brake system can include brake port circuit, drive circuit and detection circuit, wherein the brake port circuit directly controls the brake action of the servo motor, the drive circuit is responsible for generating control signals to drive the brake port circuit, and the detection circuit is used to monitor the working state of the servo motor in real time. The whole system is controlled by a micro control unit (MCU), which not only sends control signals to the drive circuit to adjust the working of the brake motor, but also receives state feedback from the detection circuit to ensure the stability and safety of the system. Through this integrated control and monitoring mechanism, the servo motor brake system can provide accurate control and timely fault response under various working conditions. The undershoot overvoltage protection circuit provided in the servo brake system of the application can cut off the power supply when the input voltage of the power supply is outside the preset working voltage range, so as to realize the undershoot protection or overvoltage protection of the servo motor, avoid the damage of the servo motor, and improve the safety and stability of the whole system.

[0031] The following will be described with reference to the drawings:

[0032] Reference is made to the accompanying drawings Figure 1 It shows the structure of a control circuit of a servo motor provided by the application. As shown in Figure 1As shown, it comprises: a driving circuit 100, an under-voltage over-voltage protection circuit 200, a brake port circuit (or connector) 300, and a servo motor 400. The brake port circuit 300 is connected with the servo motor 400, and is used to control the brake of the servo motor 400 according to a control signal; the driving circuit 100 is connected with the brake port circuit 300, and is used to send the control signal to the brake port circuit 300; the input end of the under-voltage over-voltage protection circuit 200 is connected with the power supply of the servo motor 400 through the brake port circuit 300, and the output end of the under-voltage over-voltage protection circuit 200 is connected with the driving circuit 100; when the input voltage of the power supply is out of a preset working voltage range, the under-voltage over-voltage protection circuit 200 is used to cut off the input of the power supply, so that the brake port circuit 300 cannot control the brake of the servo motor 400, and the under-voltage over-voltage protection of the servo motor 400 is realized.

[0033] The input end of the under-voltage over-voltage protection circuit 200 is connected with the power supply of the servo motor 400 through the brake port circuit 300, and monitors the input voltage of the power supply in real time. When the input voltage is out of the preset working voltage range, the under-voltage over-voltage protection circuit 200 cuts off the input of the power supply, so that no matter whether the control signal instructs the brake port circuit 300 to control the brake of the servo motor, the brake port circuit 300 cannot control the servo motor to perform corresponding operation; when the input voltage of the power supply is in the preset working voltage range, the driving circuit 100 can drive the brake port circuit 300 based on the control signal, so that the brake port circuit 300 controls the brake of the servo motor 400.

[0034] The driving circuit of the embodiment of the present application is directly connected with the servo motor through the brake port circuit, so that the brake port circuit effectively controls the brake of the servo motor according to the control signal. The under-voltage over-voltage protection circuit is introduced, the input voltage of the power supply is monitored, the system is ensured to run in the preset working voltage range, once the input voltage is out of the preset working voltage range, the under-voltage over-voltage protection circuit automatically cuts off the power supply, the under-voltage over-voltage protection of the servo motor is realized, the damage of the servo motor caused by voltage abnormality is prevented, and the safety and stability of the whole system are improved.

[0035] In an embodiment of the present application, reference is made to the accompanying drawings Figure 1 Further comprising: a micro control unit 500 and a detection circuit 600. The micro control unit 500 is connected with the driving circuit 100, and is used to send the control signal to the driving circuit 100; the detection circuit 600 is connected with the driving circuit 100 and the micro control unit 500 respectively, and is used to detect the working voltage between the two ends of the servo motor 400, and feed back the working state of the servo motor 400 to the micro control unit 500 based on the working voltage.

[0036] The micro control unit 500 sends a control signal to the driving circuit 100, and the driving circuit 100 sends the control signal to the brake port circuit 300, so that the brake port circuit 300 controls the brake or release of the servo motor 400 based on the control signal. Wherein, when the control signal is high, the control signal indicates that the servo motor 400 is braked; when the control signal is low, the control signal indicates that the servo motor 400 stops working. The detection circuit 600 essentially monitors the working state of the servo motor 400 by detecting the working voltage across the servo motor 400. Wherein, when the detection circuit 600 detects the working voltage of the servo motor 400 in real time, it can generate a feedback signal based on the working voltage and send the feedback signal to the micro control unit 500 to inform the micro control unit 500 of the current working state of the servo motor 400. For example, when the input voltage of the power supply is within the preset working voltage range, and the control signal is used to indicate that the servo motor 400 stops working, the feedback signal is high, indicating that the servo motor 400 is in a safe state, and the servo motor 400 stops working; when the input voltage of the power supply is within the preset working voltage range, and the control signal is used to indicate that the servo motor 400 is braked, the feedback signal is low, indicating that the servo motor 400 is in a safe state, and the servo motor 400 is braked. For another example, when the input voltage of the power supply is outside the preset working voltage range, whether the control signal indicates that the servo motor 400 is braked or stopped, the feedback signal is high, indicating that the current voltage state of the servo motor 400 is unsafe.

[0037] The micro control unit and the driving circuit are connected to realize precise control and monitoring of the brake motor. The micro control unit is responsible for sending control signals to the driving circuit to control the start and stop of the brake motor. The detection circuit further enhances the reliability of the system. It is not only connected to the driving circuit, but also connected to the micro control unit, and detects the working voltage across the servo motor in real time. Based on these detected working voltages, the detection circuit feeds back the working state of the servo motor to the micro control unit, ensuring that the system can respond in time when the voltage is abnormal, preventing the motor from being damaged. This integrated control and monitoring mechanism improves the safety, stability and response speed of the system, and also facilitates fault diagnosis and system maintenance.

[0038] Reference is made to the accompanying drawings Figure 2 which shows a circuit diagram of an under-voltage and over-voltage protection circuit provided by an embodiment of the application. Wherein, the under-voltage and over-voltage protection circuit includes an over-voltage protection circuit and an under-voltage protection circuit. As shown in the figure, Figure 2As shown, the overvoltage protection circuit includes: a first resistor R1, a second resistor R4, a first diode D2, a first capacitor C1 and a first triode Q2. The base of the first triode Q2 is connected to the first resistor R1 and the second resistor R4 respectively, the collector of the first triode Q2 is connected to the gate of the first MOS Q1 in the under-voltage protection circuit, and the emitter of the first triode Q2 is connected to the source of the first MOS Q1; the first capacitor C1 is connected in parallel with the first resistor R1, the cathode of the first diode D2 is connected to the second resistor R4, and the anode of the first diode D2 is grounded.

[0039] The Figure 2 VIN in the under-voltage protection circuit is the input voltage of the power supply, and the VIN end is connected to the input end of the protection circuit through the brake port circuit. MOTOR+ is the positive end of the driving power supply of the servo motor, which is connected to the input end of the driving circuit through the output end of the protection circuit. The first resistor R1, the second resistor R4, the first diode D2, the first capacitor C1 and the first triode Q2 constitute an overvoltage protection circuit (or a first-stage protection circuit). When the input voltage of the power supply is within the preset working voltage range (the preset working voltage range can be 18V-30V), the first MOS Q1 is normally turned on, and at this time the current flows through the first MOS Q1 to supply power to the subsequent circuit. When the input voltage of the power supply is greater than the maximum value in the preset working voltage range, the first diode D2 works in a stable voltage state, the current flows in through the VIN end, flows through the first resistor R1, the second resistor R4 and the first diode, and then is grounded. At the same time, the first diode D2 works in a stable voltage state, and the voltage difference between the first resistor R1 and the second resistor R4 is determined by the voltage difference between the VIN end and the voltage of the first diode D2. When the voltage difference between the two ends of the first resistor R1 is greater than the turn-on voltage of the first triode Q2, the first triode Q2 is turned on, and the first MOS Q1 is cut off, so that the current cannot flow through the first MOS Q1 to the subsequent circuit (i.e. cannot supply power to the servo motor), thereby realizing overvoltage protection of the subsequent circuit.

[0040] Further, as shown in Figure 2 , the under-voltage protection circuit includes: a third resistor R2, a fourth resistor R5, a second diode D3. The one end of the third resistor R2 is connected to the gate of the first MOS Q1, and the other end is connected to the emitter of the first triode Q2; the cathode of the second diode D3 is connected to the gate of the first MOS Q1 through the fourth resistor R5, and the anode of the second diode D3 is grounded; the drain of the first MOS Q1 is connected to the positive end (MOTOR+) of the driving power supply of the servo motor.

[0041] Similarly, the third resistor R2, the fourth resistor R5, the second diode D3 and the first MOS Q1 constitute an under-voltage protection circuit (or second level protection circuit). When the input voltage of the power supply is within the preset working voltage range, the first MOS Q1 is normally turned on, and at this time the current passes through the first MOS Q1 to supply power to the subsequent circuit. When the input voltage of the power supply is less than the minimum value in the preset working voltage range, the first MOS is cut off, and at this time the current cannot pass through the first MOS to supply power to the subsequent circuit (i.e. cannot supply power to the servo motor), thereby playing an under-voltage protection role for the subsequent circuit.

[0042] The embodiment of the present application integrates the over-voltage protection circuit and the under-voltage protection circuit, thereby significantly improving the safety and reliability of the system. The over-voltage protection circuit is composed of the first resistor, the second resistor, the first diode, the first capacitor and the first triode. When the input voltage exceeds the preset working voltage range, the over-voltage protection circuit responds quickly, cuts off the first MOS through the conduction of the first triode, thereby preventing the current from flowing to the servo motor, avoiding damage to the servo motor caused by over-voltage, realizing over-voltage protection of the servo motor, and improving the safety and stability of the entire system. The under-voltage protection circuit is composed of the third resistor, the fourth resistor and the second diode. They play a role when the input voltage is lower than the working voltage range, ensuring that the first MOS is cut off under the condition of under-voltage, preventing performance degradation or damage caused by the operation of the servo motor under low voltage, realizing under-voltage protection of the servo motor, and thereby improving the safety and stability of the entire system.

[0043] In an embodiment of the present application, reference is made to the accompanying drawings Figure 2 The over-voltage and under-voltage protection circuit further comprises a third diode D1, a fuse F1, a first TVS tube D6 and a fifth resistor R3. The anode of the third diode D1 is connected to the power supply, and the cathode of the third diode D1 is connected to the first resistor R1 through the fuse F1; one end of the first TVS tube D6 is connected to the power supply, and the other end is grounded; one end of the fifth resistor R3 is connected to the positive terminal of the driving power supply, and the other end is grounded.

[0044] The third diode D1 is a reverse prevention diode, which is used to prevent the input voltage from being reversed. The first TVS tube D6 is used to prevent the input voltage from exceeding the threshold value and causing damage to the subsequent circuit. The fuse (or self-recovery fuse) F1 is used to prevent the short circuit of the back-end load and cause damage to the key components. The fifth resistor R3 is essentially a normal load, which is used to prevent the absence of the servo motor from being disconnected, thereby causing the absence of the load and leading to abnormal feedback signals.

[0045] Reference is made to the accompanying drawings Figure 3 Fig. 1 shows a circuit diagram of a driving circuit according to an embodiment of the present application. As shown in Fig. 1, the driving circuit comprises a power supply, a driving power supply, a servo motor and a feedback circuit. Figure 3The sixth resistance R10, the seventh resistance R12, the eighth resistance R13, the ninth resistance R14, the tenth resistance R15, the eleventh resistance R16, the second triode Q3, the third triode Q5, the second MOS Q4 and the fourth diode D5 constitute a push-pull circuit. The push-pull circuit is connected with the servo motor and is used for controlling the servo motor to brake. The first input end 1 of the first optocoupler U2 is connected with the output pin of the micro control unit through the sixth resistance R10, the first output end 4 of the first optocoupler U2 is connected with the servo motor (refer to the MT in the attached Figure 3 figure), and the second output end 3 of the first optocoupler is connected with the push-pull circuit. The base of the second triode Q3 is connected with the seventh resistance R12, the collector of the second triode Q3 is connected with the second output end 3, and the emitter of the second triode Q3 is connected with the eighth resistance R13. The base of the third triode Q5 is connected with the ninth resistance R14, the collector of the third triode Q5 is grounded, and the emitter of the third triode Q5 is connected with the eighth resistance R13. One end of the tenth resistance R15 is connected with the eighth resistance R13, and the other end is grounded. One end of the eleventh resistance R16 is connected with the second output end 3, and the other end is grounded. The gate of the second MOS Q4 is connected with the eighth resistance R13, the source of the second MOS Q4 is grounded, and the drain of the second MOS Q4 is connected with the servo motor (refer to the MT in the attached Figure 3 figure) through the negative end of the driving power supply of the servo motor. The cathode of the fourth diode D5 is connected with the eighth resistance R13, and the anode of the fourth diode D5 is grounded.

[0046] The attached Figure 3In this circuit, MT_CTRL is the control signal from the microcontroller to the drive circuit. When the control signal is high, the first optocoupler U2 is turned on, causing the push-pull circuit to generate a drive signal. This drive signal turns on the second MOSFET, thereby controlling the servo motor's brake. When the control signal is low, the first optocoupler U2 is turned off, causing the push-pull circuit to generate a drive signal. This drive signal turns off the second MOSFET Q4, thereby stopping the servo motor. The specific circuit states are as follows: When the control signal is high, the second output terminal 3 of the first optocoupler U2 outputs a high level, the second transistor Q3 is turned on, and the third transistor Q5 is turned off. At this time, the second transistor Q3, the eighth resistor R13, and the tenth resistor R15 form a circuit, thereby making the gate (or gate electrode) input of the second MOSFET Q4 high, which in turn drives the servo motor to hold the brake. When the control signal is low, the second output terminal 3 of the first optocoupler U2 outputs a low level, the second transistor Q3 is turned off, and the third transistor Q5 is turned on. At this time, the third transistor Q5 and the eighth resistor R13 form a circuit, thereby making the gate (or gate electrode) input of the second MOSFET Q4 low, which in turn stops the servo motor from working.

[0047] In one embodiment of this application, reference is made to the appendix. Figure 3 The drive circuit also includes: a twelfth resistor R11, a fifth diode D4, and a second capacitor C4. One end of the twelfth resistor R11 is connected to the sixth resistor R10, and the other end is grounded; one end of the second capacitor C4 is connected to the sixth resistor R10, and the other end is grounded; the cathode of the fifth diode D4 is connected to the servo motor, and the anode of the fifth diode D4 is connected to the servo motor through the negative terminal of the drive power supply. The twelfth resistor R11 is used to increase the minimum operating voltage of the servo motor, the second capacitor C4 is used for filtering, and the fifth diode D4 is a freewheeling diode used to dissipate the reverse induced electromotive force of the coil.

[0048] Reference Appendix Figure 4 The diagram illustrates a detection circuit according to an embodiment of this application. Figure 4 As shown, it includes: a second optocoupler U1, a thirteenth resistor R6, and a fourteenth resistor R7. The first input terminal 1 of the second optocoupler U1 is connected to the positive terminal MOTOR+ of the servo motor's drive power supply via the thirteenth resistor R6; the second input terminal 2 of the second optocoupler U1 is connected to the negative terminal MOTOR- of the drive power supply; the first output terminal 4 of the second optocoupler U1 is connected to the first power supply 3V3 via the fourteenth resistor R7; and the second output terminal 3 of the second optocoupler U1 is grounded.

[0049] The detection circuit detects the working voltage of the servo motor in real time through the positive terminal MOTOR+ and the negative terminal MOTOR- of the driving power supply. The thirteenth resistor R6 can be the input front end of the second optocoupler U1, and when the servo motor works normally, the input front end of the second optocoupler U1 is turned on. When the servo motor stops working, the input front end of the second optocoupler U1 is cut off.

[0050] When the input voltage of the power supply is within the preset working voltage range, if the control signal is high, the input front end of the second optocoupler U1 is turned on, and the feedback signal VDEC sent by the detection circuit to the micro control unit is low, at this time, the servo motor is in the normal working state. When the input voltage of the power supply is within the preset working voltage range, if the control signal is low, the input front end of the second optocoupler U1 is cut off, and the feedback signal VDEC sent by the detection circuit to the micro control unit is high, at this time, the servo motor is in the stop working state.

[0051] When the input voltage of the power supply is outside the preset working voltage range, no matter whether the control signal is high or low, the input front end of the second optocoupler U1 is cut off, and the feedback signal VDEC sent by the detection circuit to the micro control unit is high, at this time, the servo motor is in the stop working state.

[0052] In an embodiment of the present application, reference is made to the accompanying drawings Figure 4 In an embodiment of the present application, reference is made to the accompanying drawings

[0053] The embodiment of the present application further provides a servo brake system, which comprises the control circuit of the servo motor according to any one of the above embodiments.

[0054] It should be noted that the above embodiments can be freely combined according to needs. The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, on the premise of not departing from the principle of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be regarded as the protection scope of the present application.

Claims

1. A control circuit for a servo motor, characterized by comprising: The application relates to a servo motor overvoltage and undervoltage protection circuit. The servo motor overvoltage and undervoltage protection circuit comprises a brake port circuit connected with the servo motor and used for controlling the servo motor brake according to a control signal; a driving circuit connected with the brake port circuit and used for sending the control signal to the brake port circuit; and an overvoltage and undervoltage protection circuit with an input end connected with a power supply of the servo motor through the brake port circuit and an output end connected with the driving circuit. When the input voltage of the power supply is out of a preset working voltage range, the overvoltage and undervoltage protection circuit is used for cutting off the input of the power supply, so that the brake port circuit cannot control the servo motor brake, and overvoltage protection or undervoltage protection of the servo motor is realized. The servo motor overvoltage and undervoltage protection circuit further comprises a micro control unit connected with the driving circuit and used for sending the control signal to the driving circuit; and a detection circuit connected with the driving circuit and the micro control unit respectively and used for detecting the working voltage between the two ends of the servo motor and feeding back the working state of the servo motor to the micro control unit based on the working voltage. The overvoltage and undervoltage protection circuit comprises an overvoltage protection circuit and an undervoltage protection circuit.

2. The control circuit for a servo motor according to claim 1, wherein The overvoltage protection circuit comprises a first resistor, a second resistor, a first triode with a base connected with the first resistor and the second resistor, a collector connected with the gate of a first MOS tube in the undervoltage protection circuit and an emitter connected with the source of the first MOS tube, a first capacitor connected with the first resistor in parallel, and a first diode with a cathode connected with the second resistor and an anode grounded. The undervoltage protection circuit comprises a fourth resistor, a third resistor with one end connected with the gate of the first MOS tube and the other end connected with the emitter of the first triode, a second diode with a cathode connected with the gate of the first MOS tube through the fourth resistor and an anode grounded, and a drain of the first MOS tube connected with the positive end of a driving power supply of the servo motor. The overvoltage and undervoltage protection circuit further comprises a fuse, a third diode with an anode connected with the power supply and a cathode connected with the first resistor through the fuse, a first TVS tube with one end connected with the power supply and the other end grounded, and a fifth resistor with one end connected with the positive end of the driving power supply and the other end grounded.

3. The control circuit for a servo motor according to claim 1, wherein The driving circuit comprises a sixth resistor, a push-pull circuit connected with the servo motor and used for controlling the servo motor brake, a first optocoupler with a first input end connected with the output pin of the micro control unit through the sixth resistor, a first output end connected with the servo motor and a second output end connected with the push-pull circuit. The push-pull circuit comprises a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first transistor with a base connected with the seventh resistor and the eighth resistor, a collector connected with the gate of a second MOS tube in the undervoltage protection circuit and an emitter connected with the source of the second MOS tube, a second capacitor connected with the seventh resistor in parallel, a second diode with a cathode connected with the eighth resistor and an anode grounded, a third diode with an anode connected with the power supply and a cathode connected with the first resistor through the fuse, a second TVS tube with one end connected with the power supply and the other end grounded, and a sixth resistor with one end connected with the positive end of the driving power supply and the other end grounded. ​ ​ ​ 4. The control circuit for a servo motor according to claim 3, wherein ​ ​ ​ ​ ​ 5. The control circuit for a servo motor according to claim 4, wherein ​ ​ ​ ​ ​ 6. The control circuit for a servo motor according to claim 2, wherein ​ ​ ​ ​ 7. The control circuit for a servo motor according to claim 6, wherein ​ a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a second transistor, a third transistor, a second MOS transistor and a fourth diode; a base of the second transistor is connected with the seventh resistor, a collector of the second transistor is connected with the second output, and an emitter of the second transistor is connected with the eighth resistor; a base of the third transistor is connected with the ninth resistor, a collector of the third transistor is grounded, and an emitter of the third transistor is connected with the eighth resistor; one end of the tenth resistor is connected with the eighth resistor, and the other end is grounded; one end of the eleventh resistor is connected with the second output, and the other end is grounded; a gate of the second MOS transistor is connected with the eighth resistor, a source of the second MOS transistor is grounded, and a drain of the second MOS transistor is connected with the servo motor through a negative end of a driving power supply of the servo motor; a cathode of the fourth diode is connected with the eighth resistor, and an anode of the fourth diode is grounded.

8. The control circuit for a servo motor according to claim 7, wherein The driving circuit further comprises: a twelfth resistor, one end of the twelfth resistor is connected with the sixth resistor, and the other end is grounded; a second capacitor, one end of the second capacitor is connected with the sixth resistor, and the other end is grounded; a fifth diode, a cathode of the fifth diode is connected with the servo motor, and an anode of the fifth diode is connected with the servo motor through a negative end of the driving power supply.

9. The control circuit for a servo motor according to claim 2, wherein The detection circuit comprises: a second optocoupler, a first input end of the second optocoupler is connected with a positive end of a driving power supply of the servo motor through a thirteenth resistor, a second input end of the second optocoupler is connected with a negative end of the driving power supply, a first output end of the second optocoupler is connected with a first power supply through a fourteenth resistor, and a second output end of the second optocoupler is grounded.

10. The control circuit for a servo motor according to claim 9, wherein The detection circuit further comprises: a fifteenth resistor, one end of the fifteenth resistor is connected with the thirteenth resistor, and the other end is connected with the negative end of the driving power supply; a third capacitor, the third capacitor is connected with the fifteenth resistor in parallel; a sixteenth resistor, one end of the sixteenth resistor is connected with the first output end of the second optocoupler, and the other end is connected with a fourth capacitor and the micro control unit respectively.

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