CN221103018U - Motor protection circuit - Google Patents

Abstract

The utility model provides a motor protection circuit, which comprises: the current sampling circuit, the amplifying circuit, the comparing circuit, the MCU control circuit and the motor driving circuit; the current sampling circuit and the motor driving circuit are electrically connected with the motor, the amplifying circuit is electrically connected with the current sampling circuit, one end of the MCU control circuit and one end of the comparison circuit are electrically connected with the amplifying circuit, and the other end of the MCU control circuit and the other end of the comparison circuit are electrically connected with the motor driving circuit. Through the implementation of the utility model, the MCU control circuit or the non-MCU control circuit is adopted to compare the output signals, and when the output signals are judged to exceed the preset threshold value, the motor driving circuit is controlled to turn off the motor, so that the stable operation of the motor is ensured.

Description

Motor protection circuit

Technical Field

The utility model relates to the technical field of circuits, in particular to a motor protection circuit.

Background

The key electric device of the motor is a coil, and the coil is very sensitive to current and temperature in the running process of the motor; when the motor is started and locked, the motor generates great current impact, the currents are converted into heat, particularly when the motor is locked, the kinetic energy is zero, all the power of the motor is converted into heat, and the motor can be burnt out in a short time; meanwhile, when the motor is in overload operation for a long time, the coil can gradually accumulate heat until the coil is burnt.

In order to control the cost and reduce the process difficulty, most motors are not designed for protection; and partial products only collect motor current through MCU when designing protection circuit, judge overcurrent and trigger protection, however this kind of protection mode can exist because the motor starts and stops the in-process and produce great interference pulse, MCU extremely easily receives strong pulse to disturb dead halt, run and fly, leads to the problem that the protection action became invalid, therefore, prior art needs to improve.

Disclosure of utility model

The utility model provides a motor protection circuit, which aims to solve the problem of lower reliability of detection protection by adopting a single MCU in the related technology.

In order to solve the above technical problems, the present utility model provides a motor protection circuit, including: the current sampling circuit, the amplifying circuit, the comparing circuit, the MCU control circuit and the motor driving circuit; the current sampling circuit and the motor driving circuit are electrically connected with the motor, the amplifying circuit is electrically connected with the current sampling circuit, one end of the MCU control circuit and one end of the comparison circuit are electrically connected with the amplifying circuit, and the other end of the MCU control circuit and one end of the comparison circuit are electrically connected with the motor driving circuit;

The motor comprises a temperature switch, and the temperature switch is electrically connected with the current sampling circuit;

the MCU control circuit comprises an analog-to-digital converter, and the analog-to-digital converter is electrically connected with the amplifying circuit.

As can be seen from the above description, the present utility model has the following advantageous effects compared with the related art:

The current of the coil is collected through the current collection circuit, after the output signal of the current collection circuit is amplified through the amplifying circuit, the output signal can be compared through the MCU control circuit or the non-MCU control circuit, when the output signal is judged to exceed the preset threshold value, the motor driving circuit is controlled to turn off the motor, and a double-control protection mechanism is adopted, so that the stable operation of the motor is ensured.

Drawings

Fig. 1 is a basic circuit schematic diagram of a motor protection circuit according to an embodiment of the present utility model;

Fig. 2 is a basic circuit schematic of a motor driving circuit according to an embodiment of the present utility model;

FIG. 3 is a basic circuit schematic of a solid state relay control circuit according to an embodiment of the present utility model;

FIG. 4 is a basic circuit schematic diagram of an MCU control circuit according to an embodiment of the utility model;

fig. 5 is a basic circuit schematic of a relay drive control circuit according to an embodiment of the present utility model;

FIG. 6 is a schematic diagram of a basic circuit of a lifting column driving circuit according to an embodiment of the present utility model;

FIG. 7 is a basic circuit schematic of a current sampling circuit according to an embodiment of the present utility model;

FIG. 8 is a basic circuit schematic of a filter circuit according to an embodiment of the utility model;

fig. 9 is a basic circuit schematic of another motor protection circuit according to an embodiment of the present utility model.

Detailed Description

In order to make the objects, technical solutions and advantages of the present utility model more apparent, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model. In addition, the technical features of the embodiments of the present utility model described below may be combined with each other as long as they do not collide with each other.

In the related art, the problem of low reliability exists in a mode of detecting and protecting by adopting a single MCU, so that the embodiment of the utility model provides a motor protection circuit.

As shown in fig. 1, an embodiment of the present utility model provides a motor protection circuit, including: a current sampling circuit 100, an amplifying circuit 200, a comparing circuit 300, an MCU control circuit 400, and a motor driving circuit 500.

Specifically, the current sampling circuit 100 and the motor driving circuit 500 are electrically connected with the motor 600, the amplifying circuit 200 is electrically connected with the current sampling circuit 100, one end of the MCU control circuit 400 and one end of the comparing circuit 300 are electrically connected with the amplifying circuit 200, and the other end of the MCU control circuit and the other end of the comparing circuit 300 are electrically connected with the motor driving circuit 500; the motor 600 includes a temperature switch 610, the temperature switch 610 is electrically connected to the current sampling circuit 100; the MCU control circuit 400 includes an analog-to-digital converter 410, and the analog-to-digital converter 410 is electrically connected to the amplifying circuit 200.

In this embodiment, the most efficient temperature is achieved by connecting the PTC temperature switch in series with the motor coil so that the temperature switch is close to the critical electrical components of the motor. The temperature switch is made of thermistor materials, is not a mechanical switch, and is high in response speed, high in reliability and low in cost. The temperature switch normally is used for collecting current by the current collecting circuit, and an output signal of the current collecting circuit is amplified by the amplifying circuit and then sent to the lower-level circuit for processing; the motor driving circuit is controlled by two paths of control paths, an MCU is used for driving the control paths in the conventional case, the motor current is processed by an amplifier and an analog-to-digital converter and then is compared and calculated in the MCU, and when the current value is greater than a software set threshold value, the MCU controls the motor driving circuit to turn off the motor; when the MCU fails to cause the failure of the control path, or when the motor is blocked instantaneously to generate instantaneous heavy current, another control path is adopted to control the motor driving circuit to turn off the motor, and the path is irrelevant to the MCU, so that the motor can be independently protected from the influence of the dead halt of the MCU, the running of programs and the like; the embodiment adopts double control protection, so that the intelligent motor has the intelligence of MCU and does not completely depend on MCU, and the stable and reliable operation of the motor can be effectively ensured.

Further, referring to fig. 2, the motor driving circuit 500 includes: a solid state relay control circuit 510, a relay drive control circuit 520, and a lifter post drive circuit 530; the solid state relay control circuit 510 is electrically connected to the MCU control circuit 400 and the comparing circuit 300, respectively, and the relay driving control circuit 520 is electrically connected to the MCU control circuit 400 and the lifting column driving circuit 530, respectively.

Further, referring to fig. 3, the solid state relay control circuit 510 includes: the switching tube comprises a first switching tube Q1, a second switching tube Q2, a first resistor R34, a second resistor R35, a third resistor R39, a first switching tube protection circuit and a second switching tube protection circuit.

Specifically, the gate of the first switching tube Q1 is electrically connected to the MCU control circuit 400, the drain is electrically connected to the solid state relay control interface J19, and the source is grounded; the first resistor R34 is electrically connected between the first switching tube Q1 and the MCU control circuit 400, and the second resistor R35 is electrically connected between the first resistor R34 and the first switching tube Q1; the gate of the second switch tube Q2 is electrically connected with the comparison circuit 300, the drain is electrically connected with the common connection end of the first resistor R34 and the second resistor R35, and the source is grounded; the third resistor R39 is electrically connected between the second switching tube Q2 and the comparison circuit 300; two ends of the first switch tube protection circuit are respectively and electrically connected with the grid electrode and the source electrode of the first switch tube Q1; two ends of the second switching tube protection circuit are respectively and electrically connected with the grid electrode and the source electrode of the second switching tube Q2.

In this embodiment, the switching tube may be a MOS tube, and as shown in fig. 4, the gate of the first switching tube Q1 is connected to a pin relay_key0 of the MCU (U5); the first switch tube protection circuit comprises a capacitor C33 and a resistor R36, wherein one end of the capacitor C33 and one end of the resistor R36 are electrically connected to the grid electrode of the first switch tube Q1, and the other end of the capacitor C33 and the other end of the resistor R36 are grounded; the second switch tube protection circuit comprises a capacitor C35 and a resistor R40, wherein one ends of the capacitor C35 and the resistor R40 are electrically connected to the grid electrode of the second switch tube Q2, and the other ends are grounded. The solid state relay in the embodiment is a motor power switch, namely the MCU controls the motor power by controlling Q1; in addition, when the overcurrent signal is generated, the motor can be turned off through the Q2, and the motor can be turned off no matter what state the MCU control signal is in, so that the motor can be turned off even if the MCU is damaged and the running program is out of control, and the reliability of protection is improved.

Further, referring to fig. 5, the relay driving control circuit 520 includes: the first driving control unit and the second driving control unit, the first driving control unit comprises a third switching tube Q3, a fourth switching tube Q4, a fourth resistor R41, a fifth resistor R42, a sixth resistor R44, a third switching tube protection circuit and a fourth switching tube protection circuit.

Specifically, the gate of the third switching tube Q3 is electrically connected to the MCU control circuit 400, the drain is electrically connected to the lifting column driving circuit 430, and the source is grounded; the fourth resistor R41 is electrically connected between the third switching tube Q3 and the MCU control circuit 400, and the fifth resistor R42 is electrically connected between the fourth resistor R41 and the third switching tube Q3; the grid electrode of the fourth switching tube Q4 is electrically connected with the first end of the second driving control unit, the drain electrode is electrically connected with the common connection end of the fourth resistor R41 and the fifth resistor R42, and the source electrode is grounded; the sixth resistor R44 is electrically connected between the fourth switching tube Q4 and the second driving control unit; two ends of the third switching tube protection circuit are respectively and electrically connected with the grid electrode and the source electrode of the third switching tube Q3; two ends of the fourth switching tube protection circuit are respectively and electrically connected with the grid electrode and the source electrode of the fourth switching tube Q4; the first end of the second driving control unit is electrically connected to the MCU control circuit 400, the second end of the second driving control unit is electrically connected to the common connection end of the first driving control unit and the MCU control circuit 400, and the third end of the second driving control unit is electrically connected to the lifting column driving circuit 430.

In this embodiment, the switching tube may be a MOS tube, and the gate of the switching tube Q3 is connected to the pin relay_key1 of the MCU (U5), and the gate of the switching tube Q4 is connected to the pin relay_key2 of the MCU (U5); the first drive control unit and the second drive control unit are similar in component devices and connection relation between the devices; according to the embodiment, the MOS tube is used for constructing the exclusive OR gate, so that the relay corresponding to ascending and descending can be prevented from being conducted simultaneously.

Still further, referring to fig. 6, the lifting column driving circuit 530 includes: the first lifting column driving control unit comprises a first RELAY RELAY1 and a second lifting column driving control unit comprises a second RELAY RELAY2.

Specifically, the first ends 6 of the first RELAY1 and the second RELAY2 are electrically connected to the RELAY driving control circuit 520, the second ends 1 are electrically connected to the power supply, the third ends 4 are electrically connected to the current sampling circuit 100, and the fourth ends 2 are electrically connected to the elevator interface.

In this embodiment, the lifting column driving circuit 530 further includes a circuit composed of capacitors C40, C41, and C42 and a circuit composed of capacitors C45, C46, and C47, wherein one ends of the capacitors C40, C41, and C42 (or C45, C46, and C47) are connected to the second end 1 of the relay, and the other ends are grounded; the device also comprises diodes D12 and D13, wherein the cathode of the diode D12 (or D13) is connected with the second end 1 of the relay, and the anode is connected with the first end 6 of the relay; the fifth end 3 of the two relays is connected with the third end 4, and the sixth end 5 is connected with the fourth end 2; the first end 6 of the RELAY RELAY1 is connected with a switching tube Q3 in the RELAY driving control circuit 520; the first terminal 6 of the RELAY2 is connected to the switching tube Q4 in the RELAY drive control circuit 520.

Further, referring to fig. 7, the current sampling circuit 100 includes: transformer T2, rectifying circuit and overvoltage protection circuit.

Specifically, the first end l_in of the transformer T2 is electrically connected to the solid state relay output interface, the second end l_out is electrically connected to the lifting column driving circuit 530, and the third end and the fourth end are respectively electrically connected to the first end and the second end of the rectifying circuit; the third end of the rectifying circuit is electrically connected with the amplifying circuit 200, and the fourth end is grounded; the first end of the overvoltage protection circuit is electrically connected with the third end of the rectifying circuit, and the second end of the overvoltage protection circuit is electrically connected with the power supply and the third end of the overvoltage protection circuit is grounded.

The rectifying circuit in this embodiment includes diodes D7, D8, D10, and D11, wherein the cathode of the diode D7 is electrically connected to the cathode of the diode D8, the anode of the diode D7 is electrically connected to the cathode of the diode D10, the anode of the diode D8 is electrically connected to the cathode of the diode D10, the anode of the diode D10 is electrically connected to the anode of the diode D11, and the common connection end of the diodes D7 and D8 is electrically connected to the amplifying circuit 200, and the common connection end of the diodes D10 and D11 is grounded; the overvoltage protection circuit consists of two diodes D9, wherein the anode of one diode is connected with the cathode of the other diode, the cathode is connected with a power supply, and the anode of the other diode is grounded; the proportion of the mutual inductor is 1000:1. the alternating current motor in the embodiment uses a mode of collecting motor current by a mutual inductor and a rectifier, can realize the function of converting a current signal into a voltage signal, and can not influence the normal operation of the motor.

Further, referring to fig. 8, the motor protection circuit further includes a filter circuit, which includes an active filter U9A, a seventh resistor R54, an eighth resistor R55, a first capacitor C49, and a second capacitor C55.

Specifically, the first end 3 of the active filter U9A is electrically connected to the current sampling circuit 100, the second end 2 is electrically connected to the third end 1 of the active filter U9A, the third end 1 of the active filter is further electrically connected to the amplifying circuit 200, the fourth end 8 of the active filter U9A is electrically connected to the power supply, and the fifth end 4 is grounded; the seventh resistor R54 is electrically connected between the current sampling circuit 100 and the active filter U9A; the eighth resistor R55 is electrically connected between the seventh resistor R54 and the active filter U9A; one end of the first capacitor C49 is electrically connected to the common connection end of the seventh resistor R54 and the eighth resistor R55, and the other end is electrically connected to the third end 1 of the active filter U9A; one end of the second capacitor C55 is electrically connected to the common connection end of the eighth resistor R55 and the active filter U9A, and the other end is grounded.

Still further, referring to fig. 9, the amplifying circuit 200 includes: an amplifier U9B, a second capacitor C57, a ninth resistor R61, and a tenth resistor R59.

Specifically, the first end 5 of the amplifier U9B is electrically connected to the active filter U9A, the second end 6 is electrically connected to one end of the ninth resistor R61, the third end 7 is electrically connected to the MCU control circuit 400 and the comparison circuit 300, the fourth end 8 is electrically connected to the power supply, and the fifth end 4 is grounded; the other end of the ninth resistor R61 is grounded; the tenth resistor R59 is electrically connected between the second end 6 and the third end 7 of the amplifier U9B; both ends of the second capacitor C57 are electrically connected to both ends of the tenth resistor R59, respectively. In addition, a resistor R56 and a capacitor C53 are further included between the filter circuit and the amplifying circuit, wherein the resistor R56 is electrically connected between the filter circuit and the amplifying circuit, one end of the capacitor C53 is electrically connected with the first end 5 of the amplifier, and the other end is grounded.

In this embodiment, since the output voltage of the current collector is very small and is in the millivolt level, the current collector cannot be directly used, and the signal size at this time is equivalent to the interference noise signal size, and the controller cannot recognize the interference noise signal, filtering and amplifying processing are required to be performed to reach the volt level, and the filtered interference noise signal is sent to a lower-level circuit for use.

Further, referring to fig. 9, the comparison circuit 300 includes: comparator U10A, transistor Q7, diode D16, third capacitor C189, eleventh resistor R52, twelfth resistor R53, and thirteenth resistor R51.

Specifically, the first end 2 of the comparator U10A is electrically connected to the reference voltage generator, the second end 3 is electrically connected to the amplifying circuit 200, the third end 1 is electrically connected to the MCU control circuit 400 and the motor driving circuit 500, the fourth end 8 is electrically connected to the power supply, and the fifth end 4 is grounded; one end of the third capacitor C189 is electrically connected to the first end 2 of the comparator U10A, and the other end is grounded; one end of the eleventh resistor R52 is electrically connected to the first end 2 of the comparator U10A, and the other end of the eleventh resistor R is electrically connected to the other end of the third capacitor C189; one end of the twelfth resistor R53 is electrically connected with the first end of the comparator U10A, and the other end of the twelfth resistor R53 is electrically connected with a power supply; one end of the thirteenth resistor R51 is electrically connected with the other end of the twelfth resistor R52, and the other end of the thirteenth resistor R51 is electrically connected with the third end 1 of the comparator U10A; the base electrode 1 of the triode Q7 is electrically connected with the MCU control circuit 400, the collector electrode 3 is electrically connected with the second end 3 of the comparator U10A, and the emitter electrode 2 is grounded; the positive electrode of the diode D16 is electrically connected to the third terminal 1 of the comparator U10A, and the negative electrode is electrically connected to the collector 3 of the transistor Q7.

The resistors R52 and R53 in the embodiment can be used to adjust the reference voltage to 1.1V, and the corresponding resistance values are 100kΩ and 200kΩ, respectively.

Further, referring to fig. 9, the comparing circuit 300 further includes: fourteenth resistor R60, fifteenth resistor R62, sixteenth resistor R63, seventeenth resistor R58, and fourth capacitor C58.

Specifically, the fifteenth resistor R62 is electrically connected between the MCU control circuit 400 and the base 1 of the transistor Q7; one end of the sixteenth resistor R63 and one end of the fourth capacitor C58 are electrically connected with the base electrode 1 of the triode Q7, and the other ends of the sixteenth resistor R63 and the fourth capacitor C58 are grounded; the fourteenth resistor R60 is electrically connected between the triode Q7 and the diode; the seventeenth resistor R58 is electrically connected between the amplifying circuit 200 and the second end of the comparator U10A.

In this embodiment, the amplifying circuit 200 and the comparing circuit 300 further include an overvoltage protection circuit D14, a resistor R57, and a capacitor C54, wherein one end of the resistor R57 is electrically connected to the amplifying circuit 200, the other end is electrically connected to the resistor R58, one end of the capacitor C54 is electrically connected to the other end of the resistor R54, the other end is grounded, a first end of the overvoltage protection circuit D14 is electrically connected to the other end of the resistor R57, a second end is grounded, and a third end is connected to a power supply; and an overvoltage protection circuit is also connected between the comparator and the MCU control circuit, two capacitors C50 and C51 are also connected between the resistor R53 and the resistor R51, one ends of the capacitors C50 and C51 are connected to the common connection end of the resistor R53 and the resistor R51, and the other ends are grounded.

The motor protection circuit provided by the embodiment of the utility model collects motor current through the current collection circuit, and an output signal of the current collection circuit is amplified by the amplifying circuit and then sent to a lower-level circuit for processing; the motor driving circuit is controlled by two paths of control paths, an MCU is used for driving the control paths in the conventional case, the motor current is processed by an amplifier and an analog-to-digital converter and then is compared and calculated in the MCU, and when the current value is greater than a software set threshold value, the MCU controls the motor driving circuit to turn off the motor; when the MCU fails to cause the failure of the control path, or when the motor is blocked instantaneously to generate instantaneous heavy current, another control path is adopted to control the motor driving circuit to turn off the motor, and the path is irrelevant to the MCU, so that the motor can be independently protected from the influence of the dead halt of the MCU, the running of programs and the like; the embodiment adopts double control protection, so that the intelligent motor has the intelligence of MCU and does not completely depend on MCU, and the stable and reliable operation of the motor can be effectively ensured.

It should be noted that, in the present disclosure, each embodiment is described in a progressive manner, and each embodiment is mainly described as different from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other.

It should also be noted that in the present disclosure, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A motor protection circuit, comprising: the current sampling circuit, the amplifying circuit, the comparing circuit, the MCU control circuit and the motor driving circuit;

The current sampling circuit and the motor driving circuit are electrically connected with the motor, the amplifying circuit is electrically connected with the current sampling circuit, one end of the MCU control circuit and one end of the comparison circuit are electrically connected with the amplifying circuit, and the other end of the MCU control circuit and one end of the comparison circuit are electrically connected with the motor driving circuit;

The motor comprises a temperature switch, and the temperature switch is electrically connected with the current sampling circuit;

the MCU control circuit comprises an analog-to-digital converter, and the analog-to-digital converter is electrically connected with the amplifying circuit.

2. The motor protection circuit according to claim 1, wherein the motor drive circuit includes: a solid state relay control circuit, a relay drive control circuit and a lifting column drive circuit; the solid-state relay control circuit is respectively and electrically connected with the MCU control circuit and the comparison circuit, and the relay driving control circuit is respectively and electrically connected with the MCU control circuit and the lifting column driving circuit.

3. The motor protection circuit of claim 2, wherein the solid state relay control circuit comprises: the switching device comprises a first switching tube, a second switching tube, a first resistor, a second resistor, a third resistor, a first switching tube protection circuit and a second switching tube protection circuit;

The grid electrode of the first switch tube is electrically connected with the MCU control circuit, the drain electrode of the first switch tube is electrically connected with the solid-state relay control interface, and the source electrode of the first switch tube is grounded; the first resistor is electrically connected between the first switching tube and the MCU control circuit, and the second resistor is electrically connected between the first resistor and the first switching tube; the grid electrode of the second switch tube is electrically connected with the comparison circuit, the drain electrode of the second switch tube is electrically connected with the common connection end of the first resistor and the second resistor, and the source electrode of the second switch tube is grounded; the third resistor is electrically connected between the second switching tube and the comparison circuit; two ends of the first switch tube protection circuit are respectively and electrically connected with the grid electrode and the source electrode of the first switch tube; and two ends of the second switching tube protection circuit are respectively and electrically connected with the grid electrode and the source electrode of the second switching tube.

4. The motor protection circuit according to claim 2, wherein the relay drive control circuit includes: the first driving control unit comprises a third switching tube, a fourth resistor, a fifth resistor, a sixth resistor, a third switching tube protection circuit and a fourth switching tube protection circuit;

The grid electrode of the third switching tube is electrically connected with the MCU control circuit, the drain electrode of the third switching tube is electrically connected with the lifting column driving circuit, and the source electrode of the third switching tube is grounded; the fourth resistor is electrically connected between the third switching tube and the MCU control circuit, and the fifth resistor is electrically connected between the fourth resistor and the third switching tube; the grid electrode of the fourth switching tube is electrically connected with the first end of the second driving control unit, the drain electrode of the fourth switching tube is electrically connected with the common connecting end of the fourth resistor and the fifth resistor, and the source electrode of the fourth switching tube is grounded; the sixth resistor is electrically connected between the fourth switching tube and the second driving control unit; two ends of the third switching tube protection circuit are respectively and electrically connected with the grid electrode and the source electrode of the third switching tube; two ends of the fourth switching tube protection circuit are respectively and electrically connected with the grid electrode and the source electrode of the fourth switching tube; the first end of the second drive control unit is electrically connected with the MCU control circuit, the second end of the second drive control unit is electrically connected with the common connection end of the first drive control unit and the MCU control circuit, and the third end of the second drive control unit is electrically connected with the lifting column driving circuit.

5. The motor protection circuit according to claim 2, wherein the lifting column driving circuit includes: the lifting column driving control device comprises a first lifting column driving control unit and a second lifting column driving control unit, wherein the first lifting column driving control unit comprises a first relay, and the second lifting column driving control unit comprises a second relay;

The first end of the first relay and the first end of the second relay are electrically connected with the relay driving control circuit, the second end of the first relay and the second relay are electrically connected with a power supply, the third end of the first relay and the second relay are electrically connected with the current sampling circuit, and the fourth end of the first relay and the fourth relay are electrically connected with the lifter interface.

6. The motor protection circuit of claim 5, wherein the current sampling circuit comprises: the transformer, the rectifying circuit and the overvoltage protection circuit;

The first end of the transformer is used for being electrically connected with the solid-state relay output interface, the second end of the transformer is electrically connected with the lifting column driving circuit, and the third end and the fourth end of the transformer are respectively electrically connected with the first end and the second end of the rectifying circuit; the third end of the rectifying circuit is electrically connected with the amplifying circuit, and the fourth end of the rectifying circuit is grounded; the first end of the overvoltage protection circuit is electrically connected with the third end of the rectifying circuit, and the second end of the overvoltage protection circuit is electrically connected with a power supply and the third end of the overvoltage protection circuit is grounded.

7. The motor protection circuit of claim 1, further comprising a filter circuit comprising an active filter, a seventh resistor, an eighth resistor, a first capacitor, and a second capacitor;

The first end of the active filter is electrically connected with the current sampling circuit, the second end of the active filter is electrically connected with the third end of the active filter, the third end of the active filter is also electrically connected with the amplifying circuit, the fourth end of the active filter is electrically connected with a power supply, and the fifth end of the active filter is grounded; the seventh resistor is electrically connected between the current sampling circuit and the active filter; the eighth resistor is electrically connected between the seventh resistor and the active filter; one end of the first capacitor is electrically connected to a common connection end of the seventh resistor and the eighth resistor, and the other end of the first capacitor is electrically connected to a third end of the active filter; one end of the second capacitor is electrically connected to the common connection end of the eighth resistor and the active filter, and the other end of the second capacitor is grounded.

8. The motor protection circuit according to claim 7, wherein the amplifying circuit includes: an amplifier, a second capacitor, a ninth resistor and a tenth resistor;

The first end of the amplifier is electrically connected with the active filter, the second end of the amplifier is electrically connected with one end of the ninth resistor, the third end of the amplifier is respectively electrically connected with the MCU control circuit and the comparison circuit, the fourth end of the amplifier is electrically connected with a power supply, and the fifth end of the amplifier is grounded; the other end of the ninth resistor is grounded; the tenth resistor is electrically connected between the second end and the third end of the amplifier; the two ends of the second capacitor are respectively and electrically connected to the two ends of the tenth resistor.

9. The motor protection circuit of claim 1, wherein the comparison circuit comprises: a comparator, a triode, a diode, a third capacitor, an eleventh resistor, a twelfth resistor and a thirteenth resistor;

The first end of the comparator is used for being electrically connected with the reference voltage generator, the second end of the comparator is electrically connected with the amplifying circuit, the third end of the comparator is electrically connected with the MCU control circuit, the fourth end of the comparator is electrically connected with a power supply, and the fifth end of the comparator is grounded; one end of the third capacitor is electrically connected to the first end of the comparator, and the other end of the third capacitor is grounded; one end of the eleventh resistor is electrically connected with the first end of the comparator, and the other end of the eleventh resistor is electrically connected with the other end of the third capacitor; one end of the twelfth resistor is electrically connected with the first end of the comparator, and the other end of the twelfth resistor is electrically connected with a power supply; one end of the thirteenth resistor is electrically connected with the other end of the twelfth resistor, and the other end of the thirteenth resistor is electrically connected with the third end of the comparator; the base electrode of the triode is electrically connected with the MCU control circuit, the collector electrode of the triode is electrically connected with the second end of the comparator, and the emitter electrode of the triode is grounded; the positive pole of the diode is electrically connected with the third end of the comparator, and the negative pole is electrically connected with the collector electrode of the triode.

10. The motor protection circuit of claim 9, wherein the comparison circuit further comprises: a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, and a fourth capacitor;

The fifteenth resistor is electrically connected between the MCU control circuit and the base electrode of the triode; one end of the sixteenth resistor and one end of the fourth capacitor are electrically connected with the base electrode of the triode, and the other end of the sixteenth resistor and the other end of the fourth capacitor are grounded; the fourteenth resistor is electrically connected between the triode and the diode; the seventeenth resistor is electrically connected between the amplifying circuit and the second end of the comparator.