CN216290741U - External dynamic brake and servo motor driving device - Google Patents

Abstract

The application provides an external dynamic brake and a servo motor driving device. The servo motor driving device comprises a servo driver and an external dynamic brake, wherein the external dynamic brake comprises a half-wave rectifying circuit and a switching circuit; the half-wave rectification circuit is connected to a three-phase output port of the servo driver and is connected to a direct-current bus output port of the servo driver through the switch circuit; the switching circuit is also connected to a signal input port of the servo driver and used for feeding back the working state of the switching circuit; the control port of the switch circuit is connected to the signal output port of the servo driver, the servo controller outputs a control signal through the signal output port, and the control switch circuit connects the half-wave rectification circuit to the inverter circuit of the servo driver to form a brake loop. The switching circuit can be realized by a relay, and the working state of the braking resistor is fed back through a pair of normally closed contact pairs and the state of the braking resistor is fed back at the same time. The application has the advantages of simple structure, reliable work and good adaptability.

Description

External dynamic brake and servo motor driving device

Technical Field

The utility model relates to the technical field of servo motors, in particular to an external dynamic brake and a servo motor driving device.

Background

Many common servo drivers do not have a dynamic braking function, and some industrial application occasions require that the dynamic braking function is additionally added to the common servo drivers. The conventional external dynamic braking device usually adopts a method of externally connecting discrete devices such as a power resistor, a relay or a contactor to obtain a dynamic braking function, not only is wiring troublesome, but also usually adopts an open-loop control method, namely, the relay is simply controlled through a signal output port of a servo driver to obtain the dynamic braking function, however, whether the relay is really opened or closed cannot be known, a control risk exists, and the servo driver can be damaged under a specific condition.

Therefore, utility model patent with publication number CN202384742U provides a servo dynamic braking function circuit, through normally closed relay control braking function circuit to through the operating condition of opto-coupler to singlechip feedback relay, with the security that improves whole circuit.

However, the technical scheme has the following defects:

1. no solution is provided to provide a modular offboard dynamic brake for a common servo drive.

2. When a normally closed relay is adopted, the optical coupler can be switched on when dynamic braking is required to be performed, however, the dynamic braking is performed usually when power failure or failure occurs, power supply voltage under the working conditions often fluctuates, so that feedback signals of the optical coupler are possibly unstable, and certain risk exists in control.

3. The primary side and the secondary side of the optocoupler are powered by the same power supply, so that certain risk exists in control.

4. Fail to provide a detection of whether the brake resistor is damaged at the same time.

SUMMERY OF THE UTILITY MODEL

In view of the above disadvantages of the prior art, an object of the present invention is to provide an external dynamic brake for connecting to a servo driver, which can reliably feed back a braking state, and a servo motor driving apparatus based on the external dynamic brake.

In order to achieve the above object, the present invention provides the following technical solutions.

An external dynamic brake is used for being connected to a servo driver and providing a dynamic braking function and comprises a half-wave rectifying circuit, a switching circuit, a control signal interface, a three-phase interface, a direct-current bus interface and a braking state interface; the half-wave rectification circuit is connected to the three-phase interface and is connected to the direct current bus interface through the switch circuit; the switch circuit is also connected to the braking state interface and used for feeding back the working state of the switch circuit; and the control port of the switch circuit is connected to the control signal interface.

The utility model aims at providing the external dynamic brake for the servo driver without the dynamic braking function, and the dynamic brake can be independently used as an optional part of the servo motor driving device without an additional power supply and other devices. The external dynamic brake is provided with a three-phase interface, a direct-current bus interface, a braking state interface and a control signal interface corresponding to the three-phase output port, the direct-current bus output port, the signal input port and the signal output port of the servo driver; the dynamic braking function can be added by simply connecting the wire with the existing servo driver. After the switching circuit connects the half-wave rectification circuit to the output port of the direct current bus of the servo driver, three diodes of the half-wave rectification circuit and three reverse diodes of the inverter circuit form reverse parallel connection respectively, and an energy consumption braking loop of the servo motor can be formed after the braking resistor is added. The switching circuit connects the half-wave rectification circuit to the high-level end or the low-level end of the output port of the direct-current bus according to the conduction directions of the three diodes of the half-wave rectification circuit.

In some embodiments, the switching circuit includes a relay, a control port of the relay is connected to the control signal interface, and the half-wave rectification circuit is connected to one of the controlled contacts of the relay; at least one of the controlled contacts of the relay is connected to the direct current bus interface, and at least one of the controlled contacts of the relay is used for feeding back the working state of the relay.

The switch circuit can be realized by a common contact relay, a solid-state relay, an optical coupler or a transistor circuit, and the common contact relay has the advantages of low cost, reliable isolation and the like. The control port of the relay is the connecting end of the control coil, and the relay can be controlled by the servo driver after being connected to the signal output port of the servo driver through the control signal interface. And a high level end or a low level end in the output port of the direct current bus is connected to a controlled contact of the relay through the interface of the direct current bus so as to realize the control of the connection between the half-wave rectification circuit and the output port of the direct current bus through the relay. The signal input port is connected to the controlled contact of the relay directly or through other elements through the braking state interface and is used for detecting the working state of the relay. The controlled contacts of the relay refer to a plurality of contacts whose interconnection state is controlled by a control port level state of the relay.

In some embodiments, the controlled contacts of the relay include a first contact pair and a second contact pair isolated from each other, the first contact pair being connected in series with the half-wave rectification circuit, the second contact pair being connected to the braking state interface; the first contact pair is a normally open contact pair, and when the control signal interface inputs a high level, the first contact pair is communicated, and the second contact pair changes a communication state. In some embodiments, the second contact pair is normally open; in some embodiments, the second contact pair is normally closed.

When the first contact pair is communicated, the half-wave rectification circuit is connected to the high-level end or the low-level end of the direct-current bus output port through the direct-current bus interface. The first contact pair is linked with the second contact pair, is normally open, and is closed according to a control signal output by a signal output port of the servo driver when braking is needed. The second contact pair can be normally opened or closed, and when the second contact pair is opened or closed, the two connecting ends of the signal input port are disconnected or short-circuited, so that the working state of the relay can be fed back to the servo driver. The technical scheme that the second contact is normally closed has better control reliability when the power supply voltage fluctuates.

In some embodiments, the switch circuit further comprises an optocoupler, the controlled contacts of the relay comprise a third contact pair and a fourth contact pair with a common moving contact, a stationary contact of the third contact pair is connected with the half-wave rectification circuit, a primary side of the optocoupler is connected to the dc bus interface through the fourth contact pair, and a secondary side of the optocoupler is connected to the braking state interface; the third contact pair is normally open, and the fourth contact pair is normally closed.

The third contact pair is formed by a common moving contact and one stationary contact, and the fourth contact pair is formed by a common moving contact and the other stationary contact. According to the setting of the conduction direction of the half-wave rectification circuit, the common moving contact is connected to the high-level end or the low-level end of the direct-current bus output port through the direct-current bus interface. And the primary side of the optocoupler is connected between the high level end and the low level end of the direct current bus output port through a fourth contact pair and a direct current bus interface. When braking is needed, the relay acts, the third contact pair is communicated, the half-wave rectification circuit is communicated to the direct current bus output port through the third contact pair and the direct current bus interface, and the motor starts braking; and meanwhile, the fourth contact is disconnected, the primary side of the optical coupler is disconnected, and the secondary side of the optical coupler feeds back the working state of the relay to the servo driver through the braking state interface and the signal input port. The primary side of the optical coupler is positioned on one side of the power circuit, and the secondary side of the optical coupler is positioned on one side of the signal circuit, so that the reliable isolation effect is realized. After braking is finished, the relay resets and disconnects the connection between the half-wave rectifying circuit and the output port of the direct current bus, and whether the relay is successfully reset or not is fed back to the servo driver through the signal input port.

In some embodiments, the switching circuit also includes an optocoupler, the controlled contact includes a fifth contact pair, and the half-wave rectification circuit is connected to the dc bus interface through the fifth contact pair; the primary side of the optical coupler is connected to the direct current bus interface through the fifth contact pair, and the secondary side of the optical coupler is connected to the braking state interface; the fifth contact pair is normally open.

In the above embodiment, the half-wave rectifier circuit and the opto-coupler use the same contact pair to complete their respective circuit connections. At the normal operating condition of motor, half-wave rectifier circuit and opto-coupler former limit all are in the state of opening a circuit, then all are in the connected state when the braking, are applicable to dynamic braking and mostly are conventional braking, appear the less application scenario of voltage fluctuation probability promptly when braking. The relay structure of this embodiment is fairly simple, simultaneously because the primary side return circuit of opto-coupler and braking circuit utilize same contact to accomplish to be connected, consequently under the condition of not considering power supply voltage fluctuation, the state feedback of relay is more direct more reliable.

In some embodiments, the half-wave rectification circuit includes a first diode, a second diode, and a third diode; the anode of the first diode is connected to the U end of the three-phase interface, the anode of the second diode is connected to the V end of the three-phase interface, the anode of the third diode is connected to the W end of the three-phase interface, and the cathode of the first diode, the cathode of the second diode and the cathode of the third diode are connected to the low-level end of the DC bus interface through a brake resistor and the switch circuit; or the cathode of the first diode is connected to the U end of the three-phase interface, the cathode of the second diode is connected to the V end of the three-phase interface, the cathode of the third diode is connected to the W end of the three-phase interface, and the anode of the first diode, the anode of the second diode, and the anode of the third diode are all connected to the high-level end of the dc bus interface through the brake resistor and the switch circuit.

The above embodiments are two parallel technical solutions, and the difference is that the conduction directions of three diodes of the half-wave rectification circuit are opposite, so that the half-wave rectification circuit needs to be connected to the high-level end or the low-level end of the dc bus output port through the switch circuit and the dc bus interface, and the primary side of the optocoupler is correspondingly connected according to the actual situation of the power polarity. The two parallel technical schemes can realize the dynamic braking function and provide more choices; or two dynamic braking circuits may be provided simultaneously, one of which serves as a backup.

In some embodiments, the number of braking resistors is at least one; the first diode, the second diode and the third diode are connected in parallel and then connected to a first end of the brake resistor, and a second end of the brake resistor is connected to the switch circuit and connected to the direct-current bus interface through the switch circuit.

In the above embodiment, three diodes share one braking resistor, and the number of components can be reduced. The brake resistor is used for rapidly consuming energy generated by the counter electromotive force during dynamic braking, and the counter electromotive force is prevented from exceeding an allowable threshold value and damaging internal devices of the servo driver.

In some embodiments, the number of braking resistors is at least one; the first diode, the second diode and the third diode are connected in parallel and then connected to the switch circuit, and the first end of one of the brake resistors is connected to the switch circuit while the other end is connected to the direct current bus interface.

In the embodiment with the optical coupler, when the brake resistor is arranged according to the connection mode, the brake resistor can also be used as a load resistor of the optical coupler, so that the number of elements can be further reduced; meanwhile, in the implementation mode that the primary side loop of the optical coupler is normally closed, the optical coupler also has the function of detecting whether the brake resistor is damaged or not: for example, when the brake resistor is damaged due to overheating and breaks, a signal fed back to the servo driver by the optical coupler pair is always a fault signal, and although the relay or the brake resistor cannot be judged to be damaged according to the fault signal, an alarm signal can be sent immediately to require maintenance so as to prevent the dynamic brake from being incapable of working when dynamic braking is required.

In some embodiments, the number of braking resistors is at least three; the first diode, the second diode and the third diode are respectively connected with one braking resistor in series and then connected to the switch circuit.

In the application occasions of frequent braking and easy overheating of the braking resistor, a plurality of braking resistors can be arranged, or the braking resistor is arranged for each diode, so that overheating is reduced.

The application also provides a servo motor driving device, which comprises a servo driver and any one of the external dynamic brakes; a three-phase output port of the servo driver is connected to the three-phase interface, a signal output port of the servo driver is connected to the control signal interface, a signal input port of the servo driver is connected to the braking state interface, and a direct current bus output port of the servo driver is connected to the direct current bus interface; the servo driver outputs a control signal through the signal output port, and controls the switching circuit to connect the half-wave rectification circuit to the inverter circuit of the servo driver, so that a brake loop is formed.

Various embodiments of the present invention have at least one of the following technical effects:

1. the dynamic brake can be used as an optional component or an additional component of the servo motor driving device, an additional power supply and other devices are not needed, the connection is convenient, and the adaptability is good;

2. the switching circuit of the dynamic brake feeds back the working state of the switching circuit to the servo driver when the braking circuit is connected or disconnected;

3. the isolation of the power circuit and the signal circuit is realized through the relay and the optocoupler, and the normal operation state of the motor is fed back through the on-state of the primary side of the optocoupler and the dynamic braking state is fed back through the open circuit of the primary side of the optocoupler, so that the control reliability is improved;

4. the braking resistor is simultaneously used as the load resistor on the primary side of the optical coupler, so that the number of elements can be reduced, and the feedback of a fault state can be provided for the servo driver through the optical coupler when the braking resistor is damaged.

Drawings

The above features, technical features, advantages and modes of realisation of the present invention will be further described in the following detailed description of preferred embodiments thereof, which is to be read in connection with the accompanying drawings.

FIG. 1 is a structural diagram of a servo motor driving apparatus and a connection circuit diagram with a motor;

FIG. 2 is a brake state circuit diagram of one embodiment of an external dynamic brake;

FIG. 3 is a circuit diagram of a portion of an inverter circuit of the servo driver;

FIG. 4 is a brake state circuit diagram of another embodiment of an external dynamic brake;

FIG. 5 is a brake state circuit diagram of another embodiment of an external dynamic brake;

FIG. 6 is a circuit diagram of a normal operating condition of the motor of another embodiment of the externally-coupled dynamic brake;

FIG. 7 is a circuit diagram of a normal operating condition of the motor of another embodiment of the externally-coupled dynamic brake;

FIG. 8 is a brake state circuit diagram of another embodiment of an external dynamic brake;

FIG. 9 is a brake state circuit diagram of another embodiment of an external dynamic brake.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will describe the specific embodiments of the present invention with reference to the accompanying drawings. The drawings in the following description are only examples of the utility model, and it will be clear to a person skilled in the art that other drawings and embodiments can be obtained from these drawings without inventive effort.

For the sake of simplicity, the drawings only schematically show the parts relevant to the present invention, and they do not represent the actual structure as a product. In some of the figures, elements having the same structure or function are shown only schematically or only schematically. In this document, "one" means not only "only one" but also a case of "more than one". The term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items. The terms "first," "second," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1, the servo motor driving apparatus provided by the present invention includes a servo driver and an external dynamic brake, wherein the servo driver has at least one signal output port DO, at least one signal input port DI, a DC bus output port DC, and a three-phase output port including a U terminal, a V terminal, and a W terminal. The external dynamic brake is an independent device and is externally connected to the existing servo driver. The external dynamic brake comprises: a control signal interface arranged in match with the signal output port DO of the servo driver, for receiving a control signal from the servo driver; the brake state interface is matched with the signal input port DI and used for feeding back a brake state; the direct-current bus interface is matched with the direct-current bus output port DC; and the three-phase interface is matched with the three-phase output port. And correspondingly connected with each other as shown in the figure, and the three-phase output port and the three-phase interface are simultaneously connected with the three-phase synchronous servo motor. Although the external dynamic brake provided by the utility model is an independent device, which can be produced separately, sold separately and stored as an accessory for standby, in actual use, the external dynamic brake needs to be connected to the servo driver to normally work, and the beneficial effects described in the specification are realized, so that for convenience of understanding and simplicity of the specification, the following embodiments are described in a manner of being connected to a servo motor driving device and a three-phase synchronous servo motor, and all connection relations of connecting to corresponding ports of the servo driver through a control signal interface, a braking state interface, a direct current bus interface, a three-phase interface and necessary external wiring are expressed in a manner of being connected to each port of the servo driver.

As shown in fig. 2, in one embodiment of the present invention, the external dynamic brake includes a half-wave rectification circuit composed of a first diode D1, a second diode D2, and a third diode D3, and a switching circuit composed of a relay K1. The half-wave rectification circuit is connected to the three-phase output port of the servo driver, namely, the anodes of the three triodes are respectively connected to the U end, the V end and the W end of the three-phase output port of the servo driver as shown in the figure. The relay K1 has a first contact pair 1A, 2A and a second contact pair 3A, 4A, the control coil of the relay K1 being connected to the signal output port DO of the servo driver. The first contact pair 1A and the second contact pair 2A are normally open, the second contact pair 3A and the second contact pair 4A are normally closed, and the first contact pair and the second contact pair are insulated and isolated from each other. When the signal output port DO is at a high level, that is, when the DO + terminal is at a high level with respect to the DO-terminal (the high state of the other port also means that the high terminal of the port is at a high level with respect to the low terminal), the relay K1 operates. The state shown in fig. 2 is the state after the relay K1 operates, and at this time, the first contact pair 1A and 2A are communicated, so that the cathodes of the three triodes are connected to the low-level end DC-of the DC bus output port DC through the first braking resistor R1. Meanwhile, the second contact pairs 3A and 4A linked with the first contact pairs 1A and 2A are disconnected, and the servo driver can judge the working state of the relay K1 according to the state of the signal input port DI. The signal input port DI of the servo driver can receive the switching value input, and the power supply is provided from the inside of the driver, so that the power supply and the load do not need to be connected.

As shown in FIG. 3, the inverter circuit of the servo driver has 6 backward diodes D4-D9. When the first contact pair 1A and 2A of the relay K1 are communicated, as can be seen from fig. 2 and 3, the first triode D1 and the backward diode D7 are connected in parallel in an inverse direction, the second triode D2 and the backward diode D8 are connected in parallel in an inverse direction, and the third diode D3 and the backward diode D9 are connected in parallel in an inverse direction, so that the three-phase synchronous servo motor can realize dynamic braking through the braking resistor R1, and the mechanical feeding of the motor is reduced when a fault, an emergency stop and a power supply are cut off.

As a variation of the embodiment shown in fig. 2, the second contact pair 3A, 4A may also be arranged to be normally open and to switch to a closed state upon actuation of relay K1. However, in the case of a fault state in which the power supply voltage is likely to fluctuate, the signal feedback reliability is inferior to that of the embodiment shown in fig. 2.

In another embodiment, shown in fig. 4, the switch circuit further comprises an optocoupler OC1, the controlled contacts of relay K1 being a third contact pair 1B, 3B and a fourth contact pair 2B, 3B having a common moving contact 3B. The stationary contact 1B of the third contact pair is connected to the cathodes of the three diodes of the half-wave rectifier circuit via a first brake resistor R1. The primary side of the optical coupler OC1 is connected to the low-level end DC-of the DC bus output port DC through the fourth contact pair 2B and 3B, and the secondary side of the optical coupler OC1 is connected to the signal input port DI. The third contact pair 1B, 3B is normally open, the fourth contact pair 2B, 3B is normally closed, and the other arrangements are the same as or similar to the embodiment shown in fig. 2. The state shown in fig. 4 is a state after the relay K1 is operated, that is, a motor braking state. At the moment, if the relay K1 works normally, the primary side of the optocoupler OC1 is in an open circuit state, and the secondary side signal input port DI feeds back an open circuit switching value; on the contrary, if the servo driver does not detect the state change of the signal input port DI, it can be determined that the relay K1 does not operate according to the control signal output from the signal output port DO. The present embodiment can reliably feed back the operating state of the relay K1 even in a state where the power supply voltage is likely to fluctuate, and is preferable in an application where control reliability needs to be ensured.

In another embodiment as shown in fig. 5, the relay K1 has a fifth pair of contacts 1C, 2C that are normally open, and the cathodes of the three diodes of the half-wave rectifier circuit are connected to the low level terminal DC-of the DC bus output port DC through the fifth pair of contacts 1C, 2C. The primary side of the optocoupler OC1 is likewise connected to contact 1C, and the other arrangements are the same as or similar to the embodiment shown in fig. 4. Fig. 5 shows an operating state of the relay K1, that is, a motor braking state, in which the secondary side signal input port DI of the optocoupler OC1 feeds back a communication switching value. Compared with the embodiment shown in fig. 4, in the normal operation state of the motor, the primary side and the secondary side of the optocoupler OC1 and the signal input port DI are all in the open circuit state, so that certain energy can be saved; however, in the case of a fault state in which the power supply voltage is likely to fluctuate, the signal feedback reliability is inferior to that of the embodiment shown in fig. 4.

In another embodiment as shown in fig. 6, the cathodes of the three diodes of the half-wave rectification circuit are respectively connected to the U terminal, the V terminal and the W terminal of the three-phase output port of the servo driver as shown in the figure, the anodes of the three diodes are all connected to the first terminal of the first brake resistor R1, and the second terminal of the first brake resistor R1 is connected to the stationary contact 1B of the third contact pair 1B, 3B; the common moving contact 3B is connected to a high-level end DC + of the output port DC of the direct-current bus; the connection mode of the primary side of the optical coupler OC1 is adjusted correspondingly, and the cathode of the primary side photodiode is connected to the low-level end DC-of the DC output port DC of the DC bus through the load resistor R2, and the anode of the primary side photodiode is connected to the stationary contact 2B of the fourth contact pair 2B and 3B. The other arrangements are the same as or similar to the embodiment shown in fig. 4. Fig. 6 shows the reset state of the relay K1, i.e., the normal motor operation state. As can be seen from fig. 6 and 3, in the operating state of the relay K1, the first transistor D1 and the backward diode D4 are connected in parallel in an inverse direction, the second transistor D2 and the backward diode D5 are connected in parallel in an inverse direction, and the third diode D3 and the backward diode D6 are connected in parallel in an inverse direction, so that the three-phase synchronous servo motor can implement dynamic braking through the braking resistor R1. This embodiment can be configured simultaneously with the embodiment shown in fig. 4 or other embodiments, and can be independently controlled by additionally configuring the signal output port and the signal input port to provide flexible and various configurations, for example, the configuration can be used as a redundant configuration of the embodiment shown in fig. 4.

In another embodiment as shown in fig. 7, on the basis of the embodiment shown in fig. 4, the load resistor R2 of the optical coupler OC1 is omitted, and the first brake resistor R1 is connected between the common moving contact 3B of the relay K1 and the low-level end DC-of the DC bus output port DC. Fig. 7 shows the reset state of the relay K1, and at this time, the first braking resistor R1 is simultaneously used as a load resistor of a primary photodiode of the opto-coupler OC1, which can simplify a circuit of the external dynamic brake. In addition, on the application occasions that braking is frequent, or braking energy is large, and the probability of damage to the first braking resistor R1 is large, when the first braking resistor R1 is damaged, the feedback detected by the signal input port of the servo driver is in a fault state, that is, the working states of the relay K1 and the first braking resistor R1 can be detected simultaneously by using the optical coupler OC 1.

In another embodiment, shown in fig. 8, the difference from the embodiment shown in fig. 4 is that the cathode of the first diode D1 is connected to the stationary contact B1 through a first braking resistor R1, the cathode of the second diode D2 is connected to the stationary contact B1 through a third braking resistor R3, and the cathode of the third diode D3 is connected to the stationary contact B1 through a fourth braking resistor R4. The embodiment is suitable for the application occasions where frequent braking is needed, or the braking energy consumption power is large and the braking resistors are easy to overheat, and can avoid overheat through a plurality of braking resistors. As shown in fig. 9, where the parameters are appropriate, a load resistor R2 on the primary side of the optocoupler OC1 may also be disposed between the common moving contact B3 and the low-level end DC-of the DC bus output terminal DC to share the braking energy consumption power, so as to further avoid overheating of the braking resistor.

The foregoing is only a preferred embodiment of the present application and the technical principles employed, and various obvious changes, rearrangements and substitutions may be made without departing from the spirit of the application. Other advantages and effects of the present application will be readily apparent to those skilled in the art from the disclosure herein. The present application is capable of other and different embodiments and its several details are capable of modifications and variations in various respects, all without departing from the spirit of the present application. The features in the above embodiments and embodiments may be combined with each other without conflict. For example, the switching circuit can also adopt an implementation mode other than a relay, the brake resistors can adopt thermistors to automatically prevent overheating, the setting modes of the brake resistors can be combined, and each brake resistor can be replaced by a plurality of brake resistors connected in series and in parallel and can be flexibly set according to application occasions.

Claims (10)

1. An external dynamic brake is characterized in that,

the system is used for being connected to a servo driver and providing a dynamic braking function and comprises a half-wave rectifying circuit, a switching circuit, a control signal interface, a three-phase interface, a direct current bus interface and a braking state interface;

the half-wave rectification circuit is connected to the three-phase interface and is connected to the direct current bus interface through the switch circuit;

the switch circuit is also connected to the braking state interface and used for feeding back the working state of the switch circuit;

and the control port of the switch circuit is connected to the control signal interface.

2. An external dynamic brake according to claim 1,

the switch circuit comprises a relay, a control port of the relay is connected to the control signal interface, and the half-wave rectification circuit is connected to one of controlled contacts of the relay;

at least one of the controlled contacts of the relay is connected to the direct current bus interface, and at least one of the controlled contacts of the relay is used for feeding back the working state of the relay.

3. An external dynamic brake according to claim 2,

the controlled contact of the relay comprises a first contact pair and a second contact pair which are isolated from each other, the first contact pair is connected with the half-wave rectifying circuit in series, and the second contact pair is connected to the braking state interface;

the first contact pair is a normally open contact pair, and when the control signal interface inputs a high level, the first contact pair is communicated, and the second contact pair changes a communication state.

4. An external dynamic brake according to claim 2,

the switch circuit further comprises an optical coupler, controlled contacts of the relay comprise a third contact pair and a fourth contact pair which have a common moving contact, a static contact of the third contact pair is connected with the half-wave rectifying circuit, a primary side of the optical coupler is connected to the direct-current bus interface through the fourth contact pair, and a secondary side of the optical coupler is connected to the braking state interface;

the third contact pair is normally open, and the fourth contact pair is normally closed.

5. An external dynamic brake according to claim 2,

the switch circuit further comprises an optical coupler, the controlled contact comprises a fifth contact pair, and the half-wave rectification circuit is connected to the direct-current bus interface through the fifth contact pair;

the primary side of the optical coupler is connected to the direct current bus interface through the fifth contact pair, and the secondary side of the optical coupler is connected to the braking state interface;

the fifth contact pair is normally open.

6. An external dynamic brake according to claim 3,

the second contact pair is normally closed.

7. An external dynamic brake according to any one of claims 1 to 6,

the half-wave rectification circuit comprises a first diode, a second diode and a third diode;

the anode of the first diode is connected to the U end of the three-phase interface, the anode of the second diode is connected to the V end of the three-phase interface, the anode of the third diode is connected to the W end of the three-phase interface, and the cathode of the first diode, the cathode of the second diode and the cathode of the third diode are connected to the low-level end of the DC bus interface through a brake resistor and the switch circuit;

or the like, or, alternatively,

the negative electrode of the first diode is connected to the U end of the three-phase interface, the negative electrode of the second diode is connected to the V end of the three-phase interface, the negative electrode of the third diode is connected to the W end of the three-phase interface, and the positive electrode of the first diode, the positive electrode of the second diode and the positive electrode of the third diode are connected to the high-level end of the direct-current bus interface through the brake resistor and the switch circuit.

8. An external dynamic brake according to claim 7,

the number of the braking resistors is at least one;

the first diode, the second diode and the third diode are connected in parallel and then connected to a first end of one brake resistor, and a second end of the brake resistor is connected to the switch circuit and connected to the direct-current bus interface through the switch circuit;

or the like, or, alternatively,

the first diode, the second diode and the third diode are connected in parallel and then connected to the switch circuit, and the first end of one of the brake resistors is connected to the switch circuit while the other end is connected to the direct current bus interface.

9. An external dynamic brake according to claim 7,

the number of the braking resistors is at least three;

the first diode, the second diode and the third diode are respectively connected with one braking resistor in series and then connected to the switch circuit.

10. A servo motor driving device is characterized in that,

comprising a servo drive and an offboard dynamic brake according to any one of claims 1 to 9;

a three-phase output port of the servo driver is connected to the three-phase interface, a signal output port of the servo driver is connected to the control signal interface, a signal input port of the servo driver is connected to the braking state interface, and a direct current bus output port of the servo driver is connected to the direct current bus interface;

the servo driver outputs a control signal through the signal output port, and controls the switching circuit to connect the half-wave rectification circuit to the inverter circuit of the servo driver, so that a brake loop is formed.

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