CN113541122B

CN113541122B - Protection device and method for servo driver and servo motor

Info

Publication number: CN113541122B
Application number: CN202110820552.7A
Authority: CN
Inventors: 刘旭龙; 谭章德; 张敏; 郑培杰; 李通; 张家梁
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2021-07-20
Filing date: 2021-07-20
Publication date: 2022-06-17
Anticipated expiration: 2041-07-20
Also published as: CN113541122A

Abstract

The invention discloses a protection device and a method of a servo driver and a servo motor, wherein the device comprises: the detection unit is used for detecting the voltage on the bus at the output end of the bus capacitor unit and recording the voltage as a detection voltage; the control unit is used for determining whether the three-phase input end of the servo driver and the three-phase output end of the servo driver are reversely connected or not according to the detection voltage under the condition that the servo driver is electrified; if the three-phase input end of the servo driver and the three-phase output end of the servo driver are reversely connected, the circuit where the bus capacitor unit is located is controlled to be disconnected, and the inversion unit is controlled to be disconnected, so that reverse connection protection of the servo driver is realized; if the three-phase input end of the servo driver and the three-phase output end of the servo driver are not reversed, the bus capacitor unit and the brake unit are controlled to be connected, and therefore the servo driver operates. According to the scheme, reverse connection protection is performed under the condition that the three-phase input and the three-phase output of the servo driver are connected in a wrong mode, and safety accidents caused after power-on are avoided.

Description

Protection device and method for servo driver and servo motor

Technical Field

The invention belongs to the technical field of motors, particularly relates to a protection device and a protection method for a servo driver and a servo motor, and particularly relates to a reverse connection protection circuit and a reverse connection protection method for input and output of the servo driver and the servo motor.

Background

Servo drivers (also called servo controllers or servo amplifiers) are controllers for controlling servo motors, have the action similar to that of a frequency converter acting on a common alternating current motor, belong to one part of a servo system and are mainly applied to high-precision positioning systems; generally, a servo motor is controlled through three modes of position, speed and moment, and high-precision positioning of a transmission system is realized. Servo drive drivers have been used in a wide variety of applications throughout the world, involving a wide variety of industries, such as machine tools, robotics, printing technology, smart homes, and so forth. The servo driver is generally a three-phase ac input, which is rectified and inverted to output three-phase ac. The connecting terminal is generally three parts of three-phase input, braking and three-phase output.

In the use process of the servo driver, the three-phase input terminal is connected to the three-phase output terminal or the three-phase output terminal is connected to the three-phase output terminal due to carelessness of an operator in many times; most of the servo drivers are not provided with a display part, and the inverter part of the three-phase output is provided with a fly-wheel diode, so that the three-phase output can enable the bus voltage to reach a normal level through the fly-wheel diode. Based on the situation, even if the three-phase input and the three-phase output are connected in error, an operator cannot perceive the error, and at the moment, if the power is on, a great potential safety hazard exists (the servo driver is burnt out slightly, and the bus capacitor explodes seriously).

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

Disclosure of Invention

The invention aims to provide a protection device and a protection method for a servo driver and a servo motor, which aim to solve the problem that a safety accident is caused if power is supplied under the condition that three-phase input and three-phase output of the servo driver are connected in a wrong way, and achieve the effect of avoiding the safety accident caused after the power is supplied by performing reverse connection protection under the condition that the three-phase input and the three-phase output of the servo driver are connected in a wrong way.

The present invention provides a protection device for a servo driver, wherein the servo driver comprises: the system comprises a rectifying unit, a bus capacitor unit, a brake unit and an inversion unit; the rectifying unit, the bus capacitor unit, the brake unit and the inversion unit are arranged between the three-phase input end of the servo driver and the three-phase output end of the servo driver; the protection device of the servo driver comprises: a detection unit and a control unit; the detection unit is arranged on a bus at the output end of the bus capacitor unit; the detection unit is configured to detect the voltage on the bus at the output end of the bus capacitor unit and record the voltage as a detection voltage; the control unit is configured to determine whether a three-phase input end of the servo driver and a three-phase output end of the servo driver are reversely connected or not according to the detection voltage under the condition that the servo driver is powered on; if the three-phase input end of the servo driver and the three-phase output end of the servo driver are reversely connected, the circuit where the bus capacitor unit is located is controlled to be disconnected, and the inversion unit is controlled to be switched off, so that reverse connection protection of the servo driver is realized; and if the three-phase input end of the servo driver and the three-phase output end of the servo driver are not reversed, controlling the connection between the bus capacitor unit and the brake unit so as to enable the servo driver to operate.

In some embodiments, the inverter unit has a driving circuit; the control unit includes: a switch unit and a control unit; the switching unit includes: a first switch module and a second switch module; the first switch module is arranged on a bus at the output end of the bus capacitor unit and is in a normally open state; the second switch module is arranged on a circuit where the bus capacitor unit is located and is in a normally-closed state; wherein, the control unit determines whether the three-phase input end of the servo driver and the three-phase output end of the servo driver are reversely connected according to the detection voltage, and comprises: the control unit is configured to determine whether the detection voltage exceeds a set voltage range, and if the detection voltage exceeds the set voltage range, determine that a three-phase input end of the servo driver and a three-phase output end of the servo driver are connected in reverse; if the detection voltage does not exceed the set voltage range, determining that the three-phase input end of the servo driver and the three-phase output end of the servo driver are not reversed; the control unit controls the disconnection of the line where the bus capacitor unit is located and controls the disconnection of the inverter unit, and the control unit comprises: the control unit is further configured to send a bus disconnection instruction for disconnecting a line where the bus capacitor unit is located and send a driving disconnection instruction for disconnecting the inverter unit when the detection voltage exceeds the set voltage range; the second switch module is configured to enable the second switch module to be in a turn-off state under the condition that the bus disconnection instruction is received, so as to disconnect a line where the bus capacitor unit is located; the driving circuit of the inversion unit is configured to turn off a driving signal of a switching tube in the inversion unit to turn off the inversion unit under the condition that the driving turn-off instruction is received; the control unit controls connection between the bus capacitor unit and the brake unit to operate the servo driver, and includes: the control unit is further configured to send out a normal working instruction under the condition that the detection voltage does not exceed the set voltage range; the first switch module is configured to enable the first switch module to be in an on state under the condition that the normal work instruction is received, so that a three-phase input end of the servo driver and a three-phase output end of the servo driver are connected.

In some embodiments, the servo driver further comprises: a power-on buffer unit; the power-on buffer unit is positioned between the rectifying unit and the bus capacitor unit and is arranged at the output end of the rectifying unit; the power-on buffer unit comprises: a third switch module; the control unit sends a normal working instruction under the condition that the detection voltage does not exceed the set voltage range, and the normal working instruction comprises the following steps: determining whether the third switch module is in an off state if the detected voltage exceeds the set voltage range; if the third switch module is in an off state, re-determining whether the detection voltage exceeds a set voltage range; and sending a normal working instruction until the detection voltage exceeds the set voltage range and the third switch module is in a closed state.

In some embodiments, the servo driver further comprises: a brake unit; the brake unit is positioned between the bus capacitor unit and the inverter unit; the detection unit includes: a sampling resistance module; the sampling resistor module is arranged between the output end of the bus capacitor unit and the brake unit and connected with the inversion unit, and is configured to detect the size and the direction of voltage between the bus capacitor unit and a collector of a switching tube in the inversion unit so as to serve as the detection voltage.

In some embodiments, the detection unit further comprises: an A/D conversion module; the A/D conversion module is arranged at the output end of the sampling resistor module and is configured to conduct A/D conversion on the voltage, detected by the sampling resistor module, between the bus capacitor unit and the collector electrode of the switch tube in the inversion unit, and then the voltage is used as the detection voltage.

In some embodiments, the detecting the voltage comprises: a first potential and a second potential; the first potential is the potential at the connecting point between the bus capacitor unit and the sampling resistor module; the second potential is a potential at a connection point between the sampling resistor module and the brake unit or the inverter unit; the control unit, confirm whether the said detection voltage exceeds the range of the settlement voltage, including: determining whether the first potential is smaller than the second potential, whether the absolute value of the difference value of the first potential and the second potential is larger than or equal to a set threshold, and whether a third switch module of a power-on buffer unit in the servo driver is disconnected; so as to: determining that the detection voltage exceeds the set voltage range when the first potential is smaller than the second potential, or when the absolute value of the difference between the first potential and the second potential is greater than or equal to a set threshold, or when a third switch module of an upper electric buffer unit in the servo driver is turned off; and determining that the detection voltage does not exceed the set voltage range under the conditions that the first potential is greater than or equal to the second potential, the absolute value of the difference value between the first potential and the second potential is less than the set threshold, and a third switch module of an electrifying buffer unit in the servo driver is closed.

In some embodiments, the servo driver further comprises: a brake unit; the brake unit is positioned between the bus capacitor unit and the inverter unit; the detection unit further comprises: a current detection module; the current detection module is arranged on a bus at the output end of the bus capacitor unit, is positioned between the second switch module and the brake unit of the servo driver, and is configured to detect the magnitude and the direction of current on the bus at the output end of the bus capacitor unit to obtain a current signal; and converting the current signal into a voltage signal as the detection voltage.

In some embodiments, the detection unit further comprises: an operational amplifier module; the operational amplifier module is arranged at the output end of the current detection module and is configured to process the voltage signal detected by the current detection module so as to convert the amplitude of the voltage signal into a voltage range which can be received by the main control module and serve as the detection voltage.

In accordance with another aspect of the present invention, there is provided a servo motor including: the protection device of the servo driver is described above.

In a method for protecting a servo driver according to another aspect of the present invention, the servo driver includes: the system comprises a rectifying unit, a bus capacitor unit, a brake unit and an inversion unit; the rectifying unit, the bus capacitor unit, the brake unit and the inversion unit are arranged between the three-phase input end of the servo driver and the three-phase output end of the servo driver; the protection method of the servo driver comprises the following steps: detecting the voltage on the bus at the output end of the bus capacitor unit through a detection unit, and recording the voltage as a detection voltage; through a control unit, under the condition that the servo driver is powered on, determining whether a three-phase input end of the servo driver and a three-phase output end of the servo driver are reversely connected or not according to the detection voltage; if the three-phase input end of the servo driver and the three-phase output end of the servo driver are reversely connected, the circuit where the bus capacitor unit is located is controlled to be disconnected, and the inversion unit is controlled to be switched off, so that reverse connection protection of the servo driver is realized; and if the three-phase input end of the servo driver and the three-phase output end of the servo driver are not reversed, controlling the connection between the bus capacitor unit and the brake unit so as to enable the servo driver to operate.

In some embodiments, the inverter unit has a driving circuit; the control unit includes: a switch unit and a control unit; the switching unit includes: a first switch module and a second switch module; the first switch module is arranged on a bus at the output end of the bus capacitor unit and is in a normally open state; the second switch module is arranged on a circuit where the bus capacitor unit is located and is in a normally-closed state; wherein, through the control unit, according to the detection voltage, determining whether the three-phase input end of the servo driver and the three-phase output end of the servo driver are reversely connected comprises: determining whether the detection voltage exceeds a set voltage range or not through a control unit, and if the detection voltage exceeds the set voltage range, determining that a three-phase input end of the servo driver and a three-phase output end of the servo driver are reversely connected; if the detection voltage does not exceed the set voltage range, determining that the three-phase input end of the servo driver and the three-phase output end of the servo driver are not reversed; through the control unit, control the disconnection of bus capacitor unit place circuit to control the contravariant unit is shut off, include: through a control unit, under the condition that the detection voltage exceeds the set voltage range, a bus disconnection instruction for disconnecting a line where the bus capacitor unit is located is sent, and a drive disconnection instruction for disconnecting the inverter unit is sent; through a second switch module, under the condition of receiving the bus disconnection instruction, enabling the second switch module to be in a disconnection state so as to disconnect a circuit where the bus capacitor unit is located; by a driving circuit of an inversion unit, under the condition of receiving the driving turn-off instruction, turning off a driving signal of a switching tube in the inversion unit so as to turn off the inversion unit; through the control unit, control switch-on between bus capacitor unit and the brake unit to make servo driver operation, include: sending a normal working instruction through a control unit under the condition that the detection voltage does not exceed the set voltage range; and through the first switch module, under the condition of receiving the normal working instruction, the first switch module is in an on state so as to switch on the three-phase input end of the servo driver and the three-phase output end of the servo driver.

In some embodiments, the servo driver further comprises: a power-on buffer unit; the power-on buffer unit is positioned between the rectifying unit and the bus capacitor unit and is arranged at the output end of the rectifying unit; the power-on buffer unit comprises: a third switch module; through the control unit, under the condition that detection voltage does not exceed the settlement voltage range, send out normal operating command, include: determining whether the third switch module is in an off state if the detected voltage exceeds the set voltage range; if the third switch module is in an off state, re-determining whether the detection voltage exceeds a set voltage range; and sending a normal working instruction until the detection voltage exceeds the set voltage range and the third switch module is in a closed state.

In some embodiments, the detecting the voltage comprises: a first potential and a second potential; wherein, in the case that the detection unit includes a sampling resistance module, the first potential is a potential at a connection point between the bus capacitor unit and the sampling resistance module; the second potential is a potential at a connection point between the sampling resistor module and the brake unit or the inverter unit; determining, by a control unit, whether the detected voltage exceeds a set voltage range, including: determining whether the first potential is smaller than the second potential, whether the absolute value of the difference value of the first potential and the second potential is larger than or equal to a set threshold, and whether a third switch module of a power-on buffer unit in the servo driver is disconnected; so as to: determining that the detection voltage exceeds the set voltage range when the first potential is smaller than the second potential, or when the absolute value of the difference between the first potential and the second potential is greater than or equal to a set threshold, or when a third switch module of an upper electric buffer unit in the servo driver is turned off; and determining that the detection voltage does not exceed the set voltage range under the conditions that the first potential is greater than or equal to the second potential, the absolute value of the difference value between the first potential and the second potential is less than the set threshold, and a third switch module of an electrifying buffer unit in the servo driver is closed.

Therefore, according to the scheme of the invention, the reverse connection protection circuit is arranged between the bus capacitor unit and the brake unit of the servo driver, after the servo driver is electrified, the bus voltage is obtained, whether the three-phase input and the three-phase output of the servo driver are reversely connected or not is determined according to the bus voltage, and the bus capacitor unit is controlled to be disconnected and the inverter unit is controlled to be disconnected under the condition that whether the three-phase input and the three-phase output of the servo driver are reversely connected or not, so that the servo driver is protected; therefore, reverse connection protection is carried out under the condition that the three-phase input and the three-phase output of the servo driver are connected in a wrong mode, and safety accidents caused after power-on are avoided.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

FIG. 1 is a schematic structural diagram of a protection apparatus for a servo driver according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an embodiment of a servo driver;

FIG. 3 is a schematic diagram of an embodiment of a servo driver with a reverse-connect protection circuit;

FIG. 4 is a control flow diagram of an embodiment of a servo driver with a reverse-connect protection circuit added;

FIG. 5 is a schematic diagram of another embodiment of a back-drive servo with a reverse-connection protection circuit;

FIG. 6 is a flowchart illustrating a method for protecting a servo driver according to an embodiment of the present invention;

fig. 7 is a schematic flow chart illustrating an embodiment of controlling the disconnection of the line where the bus capacitor unit is located and controlling the turn-off of the inverter unit in the method of the present invention;

fig. 8 is a schematic flow chart illustrating an embodiment of controlling the connection between the bus capacitor unit and the brake unit in the method of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

According to an embodiment of the present invention, there is provided a protection apparatus of a servo driver. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The servo driver includes: the device comprises a rectifying unit, a bus capacitor unit, a brake unit and an inversion unit. The rectifying unit, the bus capacitor unit, the brake unit and the inversion unit are arranged between the three-phase input end of the servo driver and the three-phase output end of the servo driver.

FIG. 2 is a schematic diagram of an embodiment of a servo driver. As shown in fig. 2, a rectifying unit, an electrifying buffer unit, a bus capacitor unit, a braking unit and an inverting unit are arranged between the three-phase input end and the three-phase output end of the servo driver. The bus capacitor unit and the brake unit are arranged in parallel. The power-on buffer unit is arranged between the rectifying unit and the bus capacitor unit. A finishing unit comprising: a rectifier bridge formed by diodes. A power-up buffer unit comprising: a resistor and a switch arranged in parallel. A bus capacitor unit comprising: and the bus capacitors are arranged in parallel. A brake unit comprising: the collector of the switch tube is connected with the anode of the diode. An inverter unit including: an inverter bridge formed by switching tubes (such as IGBT).

That is, the servo driver shown in fig. 2 includes: the device comprises a rectifying unit, an electrifying buffer unit, a bus capacitor unit, a brake unit and an inversion unit. Wherein, the rectification unit: the three-phase input alternating current is rectified into direct current. A power-on buffer unit: a resistor is connected in series in a bus loop at the moment of electrifying, and the resistor is short-circuited through a switching element after the bus voltage is stabilized, so that the current peak of the bus at the moment of electrifying is reduced. A bus capacitor unit: and stabilizing the bus voltage to prepare for subsequent inversion. A brake unit: a brake resistor is required to be externally connected, and when the motor needs to stop rotating, energy on the motor is quickly discharged through a brake part. An inversion unit: the direct current is inverted to alternating current required to drive the motor.

In practical operation, if an operator carelessly connects a three-phase input to a three-phase output, the inverter part forms a rectifier bridge through 6 freewheeling diodes, a bus capacitor can be charged similarly, but no power-on buffer exists in the process, a large current spike exists, and devices are easy to burn out. The bus voltage is normal, and some drivers can not report errors, and if operating personnel continue to make the driver work for the contravariant part IGBT opens, then can lead to the three-phase input short circuit, if the freewheeling diode burns out, then can lead to exerting reverse voltage on the bus capacitance, lead to the bus capacitance explosion.

The protection device of the servo driver comprises: a detection unit and a control unit. The detection unit is arranged on a bus of the output end of the bus capacitor unit.

The detection unit is configured to detect a voltage on a bus at an output end of the bus capacitance unit, and the voltage is recorded as a detection voltage.

The control unit is configured to determine whether the three-phase input end of the servo driver and the three-phase output end of the servo driver are reversely connected or not according to the detection voltage under the condition that the servo driver is powered on. And the number of the first and second groups,

the control unit is specifically configured to control the disconnection of the line where the bus capacitor unit is located and control the turn-off of the inverter unit to realize the reverse connection protection of the servo driver if the three-phase input end of the servo driver and the three-phase output end of the servo driver are connected reversely.

The control unit is specifically configured to control the bus capacitor unit and the brake unit to be connected to enable the servo driver to operate if the three-phase input end of the servo driver and the three-phase output end of the servo driver are not inverted, so that reliable and safe operation of the servo driver is guaranteed.

It is considered that some components may be burned out after power-up due to the operator carelessly turning the input and output of the servo driver to be reversed. If the input and output of the servo driver are reversely connected, after the servo driver is powered on, the IGBT in the servo driver is enabled, the bus capacitor may explode, and safety accidents are caused. The invention provides a reverse connection protection circuit for input and output of a servo driver, which can effectively protect the driver when the input and output of the servo driver are reversely connected.

In some embodiments, the inverter unit has a driving circuit.

The control unit includes: a switch unit and a control unit. The switching unit includes: a first switch module and a second switch module. The first switch module is arranged on a bus of the output end of the bus capacitor unit and is in a normally open state. The second switch module is arranged on a circuit where the bus capacitor unit is located and is in a normally-closed state. The control unit, such as the main control portion, may employ a controller of the servo driver.

Wherein, the control unit determines whether the three-phase input end of the servo driver and the three-phase output end of the servo driver are reversely connected according to the detection voltage, and comprises:

the control unit is configured to determine whether the detection voltage exceeds a set voltage range, and if the detection voltage exceeds the set voltage range, determine that a three-phase input end of the servo driver and a three-phase output end of the servo driver are connected reversely; and if the detection voltage does not exceed the set voltage range, determining that the three-phase input end of the servo driver and the three-phase output end of the servo driver are not reversed.

Correspondingly, the control unit controls the disconnection of the line where the bus capacitor unit is located, and controls the disconnection of the inverter unit, and the control unit comprises:

the control unit is further configured to send a bus disconnection instruction for disconnecting the line where the bus capacitor unit is located and send a driving disconnection instruction for disconnecting the inverter unit when the detection voltage exceeds the set voltage range.

The second switch module is configured to enable the second switch module to be in a turn-off state under the condition that the bus disconnection instruction is received, so that a line where the bus capacitor unit is located is disconnected.

The driving circuit of the inversion unit is configured to turn off a driving signal of a switching tube in the inversion unit to turn off the inversion unit when the driving turn-off instruction is received.

Accordingly, the control unit, which controls the connection between the bus capacitor unit and the brake unit to operate the servo driver, includes:

the control unit is further configured to issue a normal operation instruction when the detection voltage does not exceed the set voltage range.

The first switch module is configured to enable the first switch module to be in an on state under the condition that the normal working instruction is received, so as to switch on a three-phase input end of the servo driver and a three-phase output end of the servo driver, namely, switch on a bus at an output end of the bus capacitor unit and the inverter unit.

In some embodiments, the servo driver further comprises: and powering on the buffer unit. The power-on buffer unit is positioned between the rectifying unit and the bus capacitor unit and is arranged at the output end of the rectifying unit. The power-on buffer unit comprises: and a third switch module.

The control unit sends a normal working instruction under the condition that the detection voltage does not exceed the set voltage range, and the normal working instruction comprises the following steps:

the control unit is specifically further configured to determine whether the third switch module is in an off state if the detected voltage exceeds the set voltage range. And if the third switch module is in an off state, re-determining whether the detection voltage exceeds a set voltage range. And sending a normal working instruction until the detection voltage exceeds the set voltage range and the third switch module is in a closed state.

In some embodiments, the servo driver further comprises: and a brake unit. And the brake unit is positioned between the bus capacitor unit and the inverter unit.

The detection unit includes: a sampling resistor module, such as sampling resistor R1. The sampling resistor module is arranged between the output end of the bus capacitor unit and the brake unit and connected with the inversion unit, and is configured to detect the size and the direction of voltage between the bus capacitor unit and the collector of a switch tube on the switch tube in the inversion unit to serve as the detection voltage.

FIG. 3 is a schematic diagram of a servo driver with a reverse-connection protection circuit added. As shown in fig. 3, the present invention provides a reverse connection protection circuit for input and output of a servo driver, including: a sampling resistor R1, a first switch S1 and a second switch S2. The first switch S1 is disposed on the output end of the bus capacitor unit and between the bus capacitor unit and the inverter unit. The sampling resistor R1 is arranged in parallel with the first switch S1, and the sampling resistor R1 is arranged between the output end of the bus capacitor unit and the brake unit, specifically between the output end of the bus capacitor unit and the cathode of the diode in the brake unit. One end of the sampling resistor R1 connected with the bus capacitor unit is a point A, and one end of the sampling resistor R1 connected with the brake unit is a point B. The main control part is connected to the drive circuit. The driving circuit is connected to an inverter power supply. The second switch S2 is connected in series on the line where the bus capacitor unit is located and is disposed close to the first switch S1. In the power-on buffer unit, the resistor R2 and the third switch S3 are arranged between the output end of the rectifying unit and the bus capacitor unit in parallel.

In the example shown in fig. 3, a main control part for controlling the operation, protection, and the like of the entire drive. And the driving circuit is used for controlling the on and off of the IGBT in the inversion unit through a signal applied by the main control part.

In the reverse connection protection circuit shown in fig. 3, a sampling resistor R1 is used for detecting the magnitude and direction of the voltage from the bus capacitor to the collector of the IGBT upper tube in the inverter unit. The voltage direction is from the point A to the point B if the potential of the point A is higher than that of the point B, and the voltage direction is from the point B to the point A when the potential of the point A is lower than that of the point B.

In the reverse connection protection circuit shown in fig. 3, the first switch S1 and the second switch S2 may be soft switches (e.g., relays), and the on or off of the soft switches may be controlled by the main control portion. The first switch S1 is a normally open switch, and the second switch S2 is a normally closed switch.

In the example shown in fig. 3, only the reverse connection protection circuit is added, but a signal receiving end of the reverse connection protection circuit is added to the main control portion correspondingly, and the main control portion and the driving circuit are also present in fig. 2, but are not shown. When the reverse connection is detected, the main control part receives a signal given by the reverse connection protection circuit and then controls the driving circuit to turn off the IGBT. Necessary are switching devices such as the first switch S1, the second switch S2, and resistive elements such as the sampling resistor R1.

In some embodiments, the detection unit further comprises: and an A/D conversion module. The A/D conversion module is arranged at the output end of the sampling resistor module and is configured to perform A/D conversion on the voltage between the bus capacitor unit and the collector of the switching tube in the inversion unit, which is detected by the sampling resistor module, and then the voltage is used as the detection voltage.

As shown in fig. 3, the present invention provides a reverse connection protection circuit for input and output of a servo driver, further comprising: and an A/D conversion module. The A/D conversion module is arranged between the sampling resistor R1 and the main control part. In the reverse connection protection circuit shown in fig. 3, the a/D conversion module may convert analog values at two ends of the sampling resistor R1 into digital values, and feed back the digital values to the main control portion.

In the example shown in fig. 3, the a/D conversion module is used for digital-to-analog conversion. In some main control parts, there is no A/D conversion module, so the A/D conversion module needs to be separately arranged.

In some embodiments, the detecting the voltage comprises: a first potential and a second potential. The first potential is a potential at a connecting point between the bus capacitor unit and the sampling resistor module. The second potential is a potential at a connection point between the sampling resistor module and the brake unit or the inverter unit. The first potential, e.g. the potential U at point A_A. The second potential, e.g. the potential U at point B_B。

The control unit, confirm whether the said detection voltage exceeds the range of the settlement voltage, including:

the control unit is specifically further configured to determine whether the first potential is less than the second potential, whether an absolute value of a difference between the first potential and the second potential is greater than or equal to a set threshold, and whether a third switch module of a power-on buffer unit in the servo driver is turned off. The threshold, e.g., the detection voltage margin a, is set as described. So as to:

and determining that the detection voltage exceeds the set voltage range under the condition that the first potential is less than the second potential, or the absolute value of the difference value of the first potential and the second potential is greater than or equal to a set threshold, or a third switch module of an upper electricity buffer unit in the servo driver is turned off.

And determining that the detection voltage does not exceed the set voltage range under the conditions that the first potential is greater than or equal to the second potential, the absolute value of the difference value between the first potential and the second potential is less than the set threshold, and a third switch module of an electrifying buffer unit in the servo driver is closed.

FIG. 4 is a control flow diagram of an embodiment of a servo driver with a reverse-connection protection circuit added, that is, a control flow diagram after the reverse-connection protection circuit shown in FIG. 3 is applied. As shown in fig. 4, the control flow of the servo driver after adding the reverse connection protection circuit includes:

and step 1, powering on a servo driver.

And 2, setting a detection voltage margin a. The purpose of setting the detection voltage margin a is to prevent malfunction of the protection circuit caused by slight difference in potential between points a and B due to voltage fluctuation.

Step 3, judging the potential U of the point A_APotential U of point B_BWhether or not: u shape_A＜U_B∩|U_A-U_BIf the third switch S3 is turned off.

If yes, the main control part controls the second switch S2 to be switched off, and the main control part sends a switching-off instruction to enable the 6 paths of IGBTs in the inverter unit to be switched off forcibly. The reverse connection protection circuit works only when the three conditions are met, when any one of the three conditions is not met, the reverse connection protection circuit does not work, whether S3 is closed or not is judged, S3 is disconnected, the power-on buffer circuit works, S3 is closed when the bus voltage is charged to a certain value, the power-on buffer is completed, S1 is closed (at the moment, input and output are not connected reversely, and therefore the reverse connection protection circuit is short-circuited through closing S1 to prevent the reverse connection protection circuit from influencing normal work of a driver), the reverse connection protection circuit is short-circuited, and the driver works normally. The switch S3 is normally a relay, and can be implemented by determining whether the signal terminal of the relay is high (generally, when the signal terminal is high, S3 is closed, and conversely, S3 is open) or whether the S3 is a thyristor, and determining whether the driving signal of the thyristor is high or low, and the other switching devices are the same.

Otherwise, in the case where the third switch S3 is not opened, the first switch S1 is controlled to be closed.

Specifically, when the input and output of the servo driver are connected reversely, the inverter part (i.e. the inverter unit) forms a rectifier bridge through 6 freewheeling diodes, rectifies the three-phase input alternating current into direct current, and after a reverse connection protection circuit is added, because the first switch S1 is a normally open switch, a sampling resistor R1 is connected in series in a direct current loop formed after the reverse connection, and the sampling resistor R1 buffers the loop at the moment of power-on, so that the current spike is reduced, and the risk of burning out elements due to the reverse connection of the input and output is greatly reduced.

Then, the voltage at two ends of the sampling resistor R1 is collected through the A/D conversion module, and if the potential U at the point B is detected_BPotential U greater than A point_AAnd exceeds a set value a (| U)_A-U_BIf is greater than a), the main control part controls the driving circuit to force the 6 IGBTs in the inverter unit to be all applied with turn-off signals (during which the 6 IGBTs in the inverter unit cannot be turned on by any operation on the main control part until the three conditions (i.e. U) in fig. 4_A＜U_B∩|U_A-U_BAnd | ≧ a ≧ and ∞ whether the third switch S3 is open) is not satisfied, and then the main control portion can control 6 IGBTs in the inverter unit to perform turn-on operation under the condition that the third switch S3 is closed. Meanwhile, the second switch S2 is turned off, so that the bus is disconnected (i.e. the bus capacitor unit is disconnected), and the servo driver is protected.

When the driver is normally connected with the input and output signals, after the third switch S3 is detected to be closed, the first switch S1 is also closed, the reverse connection protection circuit is short, and the normal operation of the equipment cannot be influenced.

Thus, the present invention provides a reverse connection protection circuit for input and output of a servo driver, comprising: when the input and output of the servo driver are connected reversely, a voltage is generated on the sampling resistor R1 and fed back to the main control part of the servo driver through the A/D conversion module, and the main control part sends an instruction to force all IGBTs in the servo driver to apply a turn-off instruction and cut off a bus loop, so that the effect of protecting the driver is achieved. Therefore, the reverse connection protection circuit for the input and the output of the servo driver provided by the scheme of the invention can cut off the drive signal of the IGBT and the bus circuit in the servo driver when the output and the input of the servo driver are in reverse connection, so that the servo driver is effectively protected.

In some embodiments, the servo driver further comprises: and a brake unit. And the braking unit is positioned between the bus capacitor unit and the inversion unit.

The detection unit further includes: and a current detection module. A current sensing module, such as a current sensor. And an operational amplifier module, such as an operational amplifier. The current detection module is arranged on a bus at the output end of the bus capacitor unit, is positioned between the second switch module and the brake unit of the servo driver, and is configured to detect the magnitude and direction of current on the bus at the output end of the bus capacitor unit to obtain a current signal. And converting the current signal into a voltage signal as the detection voltage.

In some embodiments, the detection unit further comprises: and an operational amplifier module. And an operational amplifier module, such as an operational amplifier. The operational amplifier module is arranged at the output end of the current detection module and is configured to process the voltage signal detected by the current detection module so as to convert the amplitude of the voltage signal into a voltage range which can be received by the main control module and serve as the detection voltage.

The scheme of the invention only lists a circuit for realizing protection, and if other detection devices (such as a current sensor) are changed, the protection function can also be realized. FIG. 5 is a schematic diagram of a rear-drive servo with a reverse-connection protection circuit. In the back drive servo added with the reverse connection protection circuit as shown in fig. 5, a first switch S1 is provided on the output end of the bus capacitance unit, a current sensor is provided on the output end of the bus capacitance unit, and the current sensor is connected to the main control part through an operational amplifier. The main control part is connected to the drive circuit. The driving circuit is connected to an inverter power supply. The second switch S2 is connected in series on the line where the bus capacitor unit is located and is disposed close to the first switch S1. In the power-on buffer unit, the resistor R2 and the third switch S3 are arranged between the output end of the rectifying unit and the bus capacitor unit in parallel.

As shown in fig. 5, after the bus is changed to the current sensor, the current sensor detects the magnitude and direction of the current on the bus, the current signal is converted into a voltage signal through the inside of the current sensor, and the voltage signal is converted into a voltage range receivable by the main control board through the operational amplifier, so that the control is realized.

In the related scheme, the phase error detection circuit for the four-quadrant frequency converter is arranged, so that the problem of possible wrong wiring between the four-quadrant frequency converter and the LC filter circuit can be identified and solved, and the phase error detection circuit can be widely applied to electrical engineering. The scheme is that when detecting U, V, W phase sequence connection error, the circuit carries out a series of counter measures; the proposal is a countermeasure when U, V, W (output) is connected with L1, L2 and L3 (input) in an opposite way; u, V, W wrong connection can not cause short circuit of the circuit, only the motor stalls, the risk is small, but if the output is connected reversely with the input, a large potential safety hazard exists, and the driver can be burnt out.

Through a large number of tests, the technical scheme of the invention is adopted, the reverse connection protection circuit is arranged between the bus capacitor unit and the brake unit of the servo driver, after the servo driver is electrified, the bus voltage is obtained, whether the three-phase input and the three-phase output of the servo driver are reversely connected or not is determined according to the bus voltage, and under the condition that whether the three-phase input and the three-phase output of the servo driver are reversely connected or not, the bus capacitor unit is controlled to be disconnected, the inversion unit is controlled to be disconnected, and the servo driver is protected. Therefore, reverse connection protection is carried out under the condition that the three-phase input and the three-phase output of the servo driver are connected in a wrong mode, and safety accidents caused after power-on are avoided.

According to an embodiment of the present invention, there is also provided a servo motor corresponding to a protection device of a servo driver. The servo motor may include: the protection device of the servo driver is described above.

Since the processing and functions of the servo motor of this embodiment are basically corresponding to the embodiments, principles and examples of the foregoing devices, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.

Through a large number of tests, the technical scheme of the invention is adopted, the reverse connection protection circuit is arranged between the bus capacitor unit and the brake unit of the servo driver, after the servo driver is electrified, the bus voltage is obtained, whether the three-phase input and the three-phase output of the servo driver are reversely connected is determined according to the bus voltage, the bus capacitor unit is controlled to be disconnected under the condition that whether the three-phase input and the three-phase output of the servo driver are reversely connected is controlled, the inverter unit is controlled to be disconnected, the servo driver is protected, and the driver can be effectively protected when the input and the output of the servo driver are reversely connected.

According to an embodiment of the present invention, there is also provided a method for protecting a servo driver corresponding to a servo motor, as shown in fig. 6, which is a schematic flow chart of an embodiment of the method of the present invention. The servo driver includes: the device comprises a rectifying unit, a bus capacitor unit, a brake unit and an inversion unit. The rectifying unit, the bus capacitor unit, the brake unit and the inversion unit are arranged between the three-phase input end of the servo driver and the three-phase output end of the servo driver.

That is, the servo driver shown in fig. 2 includes: the device comprises a rectifying unit, an electrifying buffer unit, a bus capacitor unit, a brake unit and an inversion unit. Wherein, the rectification unit: the three-phase input alternating current is rectified into direct current. A power-on buffer unit: at the moment of electrifying, a resistor is connected in series in a bus loop, and after the bus voltage is stable, the resistor is short-circuited through a switching element, so that the bus current spike at the moment of electrifying is reduced. A bus capacitor unit: and stabilizing the bus voltage to prepare for subsequent inversion. A brake unit: a brake resistor is required to be externally connected, and when the motor needs to stop rotating, energy on the motor is quickly discharged through a brake part. An inversion unit: the direct current is inverted to alternating current required to drive the motor.

In practical operation, if an operator carelessly connects a three-phase input to a three-phase output, the inverter part forms a rectifier bridge through 6 freewheeling diodes, and the bus capacitor can be charged similarly, but no power-on buffer exists in the process, a large current spike exists, and devices are easily burnt out. The bus voltage is normal, and some drivers can not report the mistake, and operating personnel if continue to make the driver work for the switching-on of contravariant part IGBT then can lead to the three-phase input short circuit, if the freewheeling diode burns out, then can lead to exerting reverse voltage on the bus capacitance, lead to the bus capacitance explosion.

The protection method of the servo driver comprises the following steps: step S110 to step S140.

At step S110, the voltage on the bus at the output end of the bus capacitor unit is detected by the detection unit, and is recorded as the detection voltage.

At step S120, by the control unit, in a case where the servo driver is powered on, whether the three-phase input terminal of the servo driver and the three-phase output terminal of the servo driver are reversely connected is determined according to the detection voltage. And the number of the first and second groups,

in step S130, if the three-phase input end of the servo driver and the three-phase output end of the servo driver are connected in reverse, the control unit controls the line where the bus capacitor unit is located to be disconnected, and controls the inverter unit to be turned off, so as to implement reverse connection protection for the servo driver.

In step S140, if the three-phase input end of the servo driver and the three-phase output end of the servo driver are not inverted, the control unit controls the bus capacitor unit and the brake unit to be connected, so that the servo driver operates, and reliable and safe operation of the servo driver is ensured.

It is considered that some components may be burned out after power-up due to the operator carelessly turning the input and output of the servo driver to be reversed. If the input and output of the servo driver are reversely connected, after the power is turned on and the IGBT in the servo driver is enabled, the bus capacitor may explode, and safety accidents are caused. The invention provides a reverse connection protection circuit for input and output of a servo driver, which can effectively protect the driver when the input and output of the servo driver are reversely connected.

In some embodiments, the inverter unit has a driving circuit.

Wherein, in step S120, determining, by the control unit, whether the three-phase input terminal of the servo driver and the three-phase output terminal of the servo driver are reversely connected according to the detection voltage includes: determining whether the detection voltage exceeds a set voltage range or not through a control unit, and if the detection voltage exceeds the set voltage range, determining that a three-phase input end of the servo driver and a three-phase output end of the servo driver are reversely connected; and if the detection voltage does not exceed the set voltage range, determining that the three-phase input end of the servo driver and the three-phase output end of the servo driver are not reversed.

Correspondingly, in step S130, the control unit controls the line where the bus capacitor unit is located to be disconnected, and controls a specific process of turning off the inverter unit, which is described in the following exemplary description.

With reference to the schematic flow chart of an embodiment of controlling the disconnection of the line where the bus capacitor unit is located and controlling the turn-off of the inverter unit in the method of the present invention shown in fig. 7, a specific process of controlling the disconnection of the line where the bus capacitor unit is located and controlling the turn-off of the inverter unit in step S130 is further described, which includes: step S210 to step S230.

Step S210, through a control unit, under the condition that the detection voltage exceeds the set voltage range, a bus disconnection instruction for disconnecting the line where the bus capacitor unit is located is sent, and a drive disconnection instruction for disconnecting the inverter unit is sent.

Step S220, by the second switch module, under the condition that the bus disconnection instruction is received, the second switch module is in a shutdown state to disconnect the line where the bus capacitor unit is located.

Step S230, turning off a driving signal of a switching tube in the inverter unit through a driving circuit of the inverter unit when the driving turn-off instruction is received, so as to turn off the inverter unit.

Accordingly, in step S140, a specific process of controlling the connection between the bus capacitor unit and the brake unit through the control unit to operate the servo driver is described in the following exemplary description.

The following further describes, with reference to a schematic flow chart of an embodiment of controlling the connection between the bus capacitor unit and the brake unit in the method of the present invention shown in fig. 8, a specific process of controlling the connection between the bus capacitor unit and the brake unit in step S140, including: step S310 and step S320.

Step S310, sending a normal working instruction through the control unit under the condition that the detection voltage does not exceed the set voltage range.

Step S320, when the normal operating instruction is received, the first switch module is turned on to turn on the three-phase input terminal of the servo driver and the three-phase output terminal of the servo driver, that is, to turn on the bus at the output terminal of the bus capacitor unit and the inverter unit.

In step S310, the sending a normal operation command by the control unit when the detected voltage does not exceed the set voltage range includes: determining, by a control unit, whether the third switching module is in an off state in a case where the detection voltage exceeds the set voltage range. And if the third switch module is in an off state, re-determining whether the detection voltage exceeds a set voltage range. And sending a normal working instruction until the detection voltage exceeds the set voltage range and the third switch module is in a closed state.

In the reverse connection protection circuit shown in fig. 3, a sampling resistor R1 is used for detecting the magnitude and direction of the voltage between the bus capacitor and the collector of the IGBT in the inverter unit.

In some embodiments, the detecting the voltage comprises: a first potential and a second potential. Wherein, in a case where the detection unit includes a sampling resistance module, the first potential is a potential at a connection point between the bus capacitor unit and the sampling resistance module. The second potential is a potential at a connection point between the sampling resistor module and the brake unit or the inverter unit. The first potential, e.g. the potential U at point A_A. The second potential, e.g. the potential U at point B_B。

In step S120, determining whether the detected voltage exceeds a set voltage range by the control unit, further includes: determining, by a control unit, whether the first potential is less than the second potential, whether an absolute value of a difference between the first potential and the second potential is greater than or equal to a set threshold, and whether a third switch module of an upper power buffer unit in the servo driver is turned off; setting a threshold, such as a detection voltage margin a, as described; so as to:

and determining that the detection voltage exceeds the set voltage range when the first potential is smaller than the second potential, or when the absolute value of the difference value between the first potential and the second potential is larger than or equal to a set threshold, or when a third switch module of an upper electric buffer unit in the servo driver is turned off.

FIG. 4 is a control flow diagram of a servo driver with a reverse-connection protection circuit, i.e., the control flow diagram after the reverse-connection protection circuit shown in FIG. 3 is applied. As shown in fig. 4, the control flow of the servo driver after adding the reverse connection protection circuit includes:

and step 1, powering on a servo driver.

If yes, the main control part controls the second switch S2 to be switched off, and the main control part sends a switching-off instruction to enable the 6 paths of IGBTs in the inverter unit to be switched off forcibly.

Otherwise, open at the third switch S3In the case, the potential U at the point A is determined again_APotential U of point B_BWhether or not: u shape_A＜U_B∩|U_A-U_BWhether the third switch S3 is open ≧ a ≧ andgate. In the case where the third switch S3 is not opened, the first switch S1 is controlled to be closed.

Then, the voltage at two ends of the sampling resistor R1 is collected through the A/D conversion module, and if the potential U at the point B is detected_BPotential U greater than A point_AAnd exceeds a set value a (| U)_A-U_BIf | > a), the main control portion will control the driving circuit to force the 6 IGBTs in the inverter unit to all apply turn-off signals (during which the 6 IGBTs in the inverter unit cannot be turned on by any operation performed on the main control portion), until any one of the three conditions in fig. 4 is not satisfied (i.e., UA < UB | UA-UB | ≧ a |, and | d.n.d. the third switch S3 is turned off), and then under the condition that it is determined that the third switch S3 is closed, the main control portion can control the 6 IGBTs in the inverter unit to perform turn-on operation. Meanwhile, the second switch S2 is turned off, so that the bus is disconnected (i.e. the bus capacitor unit is disconnected), and the servo driver is protected.

Thus, the present invention provides a reverse connection protection circuit for input and output of a servo driver, comprising: when the input and output of the servo driver are connected reversely, a voltage is generated on the sampling resistor R1 and is fed back to a main control part of the servo driver through the A/D conversion module, the main control part sends an instruction to force all IGBTs in the servo driver to apply a turn-off instruction, and a bus loop is cut off, so that the effect of protecting the driver is achieved. Therefore, the reverse connection protection circuit for the input and the output of the servo driver provided by the scheme of the invention can cut off the drive signal of the IGBT and the bus circuit in the servo driver when the output and the input of the servo driver are in reverse connection, so that the servo driver is effectively protected.

Since the processing and functions implemented by the method of this embodiment substantially correspond to the embodiments, principles and examples of the servo motor, reference may be made to relevant descriptions in the foregoing embodiments without being repeated in this embodiment.

Through a large number of tests, the technical scheme of the embodiment is adopted, the reverse connection protection circuit is arranged between the bus capacitor unit and the brake unit of the servo driver, after the servo driver is powered on, the bus voltage is obtained, whether the three-phase input and the three-phase output of the servo driver are reversely connected or not is determined according to the bus voltage, and under the condition that whether the three-phase input and the three-phase output of the servo driver are reversely connected or not, the bus capacitor unit is controlled to be disconnected, the inverter unit is controlled to be disconnected, the servo driver is protected, and the servo driver is effectively protected.

In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A protection device for a servo driver, the servo driver comprising: the system comprises a rectifying unit, a bus capacitor unit, a brake unit and an inversion unit; the rectifying unit, the bus capacitor unit, the brake unit and the inversion unit are arranged between the three-phase input end of the servo driver and the three-phase output end of the servo driver;

the protection device of the servo driver comprises: a detection unit and a control unit; the detection unit is arranged on a bus at the output end of the bus capacitor unit;

the detection unit is configured to detect the voltage on the bus at the output end of the bus capacitor unit and record the voltage as a detection voltage;

the control unit is configured to determine whether a three-phase input end of the servo driver and a three-phase output end of the servo driver are reversely connected or not according to the detection voltage under the condition that the servo driver is powered on; and the number of the first and second groups,

if the three-phase input end of the servo driver and the three-phase output end of the servo driver are connected reversely, the circuit where the bus capacitor unit is located is controlled to be disconnected, and the inversion unit is controlled to be switched off, so that reverse connection protection of the servo driver is realized;

if the three-phase input end of the servo driver and the three-phase output end of the servo driver are not reversed, controlling the connection between the bus capacitor unit and the brake unit so as to enable the servo driver to operate;

the inversion unit is provided with a driving circuit;

the control unit includes: a switch unit and a control unit; the switching unit includes: a first switch module and a second switch module; the first switch module is arranged on a bus at the output end of the bus capacitor unit and is in a normally open state; the second switch module is arranged on a circuit where the bus capacitor unit is located and is in a normally-closed state; wherein the content of the first and second substances,

the control unit determines whether the three-phase input end of the servo driver and the three-phase output end of the servo driver are reversely connected according to the detection voltage, and comprises the following steps:

the control unit is configured to determine whether the detection voltage exceeds a set voltage range, and if the detection voltage exceeds the set voltage range, determine that a three-phase input end of the servo driver and a three-phase output end of the servo driver are connected reversely; if the detection voltage does not exceed the set voltage range, determining that the three-phase input end of the servo driver and the three-phase output end of the servo driver are not reversed;

the control unit controls the disconnection of the line where the bus capacitor unit is located and controls the disconnection of the inverter unit, and the control unit comprises:

the control unit is further configured to send a bus disconnection instruction for disconnecting a line where the bus capacitor unit is located and send a driving disconnection instruction for disconnecting the inverter unit when the detection voltage exceeds the set voltage range;

the second switch module is configured to enable the second switch module to be in a turn-off state under the condition that the bus disconnection instruction is received, so as to disconnect a line where the bus capacitor unit is located;

the driving circuit of the inversion unit is configured to turn off a driving signal of a switching tube in the inversion unit to turn off the inversion unit under the condition that the driving turn-off instruction is received;

the control unit controls connection between the bus capacitor unit and the brake unit to operate the servo driver, and includes:

the control unit is further configured to send out a normal working instruction under the condition that the detection voltage does not exceed the set voltage range;

the first switch module is configured to enable the first switch module to be in an on state to switch on a three-phase input end of the servo driver and a three-phase output end of the servo driver under the condition that the normal work instruction is received.

2. The servo driver protection device of claim 1, wherein the servo driver further comprises: a power-on buffer unit; the power-on buffer unit is positioned between the rectifying unit and the bus capacitor unit and is arranged at the output end of the rectifying unit; the power-on buffer unit comprises: a third switch module;

the control unit, under the condition that the detection voltage does not exceed the set voltage range, sends out normal work order, including:

determining whether the third switch module is in an off state if the detected voltage exceeds the set voltage range; if the third switch module is in an off state, re-determining whether the detection voltage exceeds a set voltage range; and sending a normal working instruction until the detection voltage exceeds the set voltage range and the third switch module is in a closed state.

3. The servo driver protection device according to claim 1 or 2, wherein the servo driver further comprises: a brake unit; the brake unit is positioned between the bus capacitor unit and the inverter unit;

the detection unit includes: a sampling resistance module; the sampling resistor module is arranged between the output end of the bus capacitor unit and the brake unit and connected with the inversion unit, and is configured to detect the size and the direction of voltage between the bus capacitor unit and a collector of a switching tube in the inversion unit so as to serve as the detection voltage.

4. The servo driver protection device of claim 3, wherein the detection unit further comprises: an A/D conversion module; the A/D conversion module is arranged at the output end of the sampling resistor module and is configured to perform A/D conversion on the voltage between the bus capacitor unit and the collector of the switching tube in the inversion unit, which is detected by the sampling resistor module, and then the voltage is used as the detection voltage.

5. The servo driver protection device of claim 3, wherein the detecting the voltage comprises: a first potential and a second potential; the first potential is the potential at the connecting point between the bus capacitor unit and the sampling resistor module; the second potential is a potential at a connection point between the sampling resistor module and the brake unit or the inverter unit;

determining whether the first potential is smaller than the second potential, whether the absolute value of the difference value of the first potential and the second potential is larger than or equal to a set threshold, and whether a third switch module of a power-on buffer unit in the servo driver is disconnected; the detection voltage is determined to be beyond the set voltage range under the condition that the first potential is smaller than the second potential, or the absolute value of the difference value of the first potential and the second potential is larger than or equal to a set threshold, or the third switch module of an upper electric buffer unit in the servo driver is turned off; and determining that the detection voltage does not exceed the set voltage range under the conditions that the first potential is greater than or equal to the second potential, the absolute value of the difference value of the first potential and the second potential is smaller than the set threshold, and a third switch module of a power-on buffer unit in the servo driver is closed.

6. The servo driver protection device according to claim 1 or 2, wherein the brake unit is located between the bus capacitor unit and the inverter unit;

the detection unit further comprises: a current detection module; the current detection module is arranged on a bus at the output end of the bus capacitor unit, is positioned between the second switch module and the brake unit of the servo driver, and is configured to detect the magnitude and the direction of current on the bus at the output end of the bus capacitor unit to obtain a current signal; and converting the current signal into a voltage signal as the detection voltage.

7. The servo driver protection device of claim 6, wherein the detection unit further comprises: an operational amplifier module; the operational amplifier module is arranged at the output end of the current detection module and is configured to process the voltage signal detected by the current detection module so as to convert the amplitude of the voltage signal into a voltage range which can be received by the control unit and serve as the detection voltage.

8. A servo motor, comprising: a protection arrangement for a servo driver according to any of claims 1 to 7.

9. A method for protecting a servo driver, the servo driver comprising: the system comprises a rectifying unit, a bus capacitor unit, a brake unit and an inversion unit; the rectification unit, the bus capacitor unit, the brake unit and the inversion unit are arranged between the three-phase input end of the servo driver and the three-phase output end of the servo driver;

the protection method of the servo driver comprises the following steps:

detecting the voltage on the bus at the output end of the bus capacitor unit through a detection unit, and recording the voltage as a detection voltage;

through a control unit, under the condition that the servo driver is powered on, determining whether a three-phase input end of the servo driver and a three-phase output end of the servo driver are reversely connected or not according to the detection voltage; and the number of the first and second groups,

the inversion unit is provided with a driving circuit;

determining, by the control unit, whether the three-phase input terminal of the servo driver and the three-phase output terminal of the servo driver are reversely connected according to the detection voltage, including:

determining whether the detection voltage exceeds a set voltage range or not through a control unit, and if the detection voltage exceeds the set voltage range, determining that a three-phase input end of the servo driver and a three-phase output end of the servo driver are reversely connected; if the detection voltage does not exceed the set voltage range, determining that the three-phase input end of the servo driver and the three-phase output end of the servo driver are not reversed;

through the control unit, control the disconnection of bus capacitor unit place circuit to control the contravariant unit is shut off, include:

through a control unit, under the condition that the detection voltage exceeds the set voltage range, a bus disconnection instruction for disconnecting a line where the bus capacitor unit is located is sent, and a drive disconnection instruction for disconnecting the inverter unit is sent;

through a second switch module, under the condition of receiving the bus disconnection instruction, enabling the second switch module to be in a disconnection state so as to disconnect a circuit where the bus capacitor unit is located;

by a driving circuit of an inverter unit, under the condition that the driving turn-off instruction is received, a driving signal of a switching tube in the inverter unit is turned off so as to turn off the inverter unit;

through the control unit, control switch-on between bus capacitor unit and the brake unit to make servo driver operation, include:

sending a normal working instruction through a control unit under the condition that the detection voltage does not exceed the set voltage range;

and through the first switch module, under the condition of receiving the normal working instruction, the first switch module is in an on state so as to switch on the three-phase input end of the servo driver and the three-phase output end of the servo driver.

10. The servo driver protection method according to claim 9, wherein the servo driver further comprises: a power-on buffer unit; the power-on buffer unit is positioned between the rectifying unit and the bus capacitor unit and is arranged at the output end of the rectifying unit; the power-on buffer unit comprises: a third switch module;

through the control unit, under the condition that detection voltage does not exceed the settlement voltage range, send out normal operating command, include:

11. The method of any of claims 9 to 10, wherein the detecting the voltage comprises: a first potential and a second potential; wherein, in the case that the detection unit includes a sampling resistance module, the first potential is a potential at a connection point between the bus capacitor unit and the sampling resistance module; the second potential is a potential at a connection point between the sampling resistor module and the brake unit or the inverter unit;

determining, by a control unit, whether the detected voltage exceeds a set voltage range, including:

determining whether the first potential is smaller than the second potential, whether the absolute value of the difference value of the first potential and the second potential is larger than or equal to a set threshold, and whether a third switch module of a power-on buffer unit in the servo driver is disconnected; the detection voltage is determined to be beyond the set voltage range under the condition that the first potential is smaller than the second potential, or the absolute value of the difference value of the first potential and the second potential is larger than or equal to a set threshold, or the third switch module of an upper electric buffer unit in the servo driver is turned off; and determining that the detection voltage does not exceed the set voltage range under the conditions that the first potential is greater than or equal to the second potential, the absolute value of the difference value between the first potential and the second potential is less than the set threshold, and a third switch module of an electrifying buffer unit in the servo driver is closed.