KR20210121566A - Power supply apparatus for driving motor and method for controlling same - Google Patents

Abstract

The present invention relates to a power supply apparatus, and more particularly, to a power supply apparatus for driving a motor to drive a device which operates together with a human, such as a cooperative robot, and a method for controlling the same. The power supply apparatus for driving a motor of the present invention includes: a motor which is connected to a power supply unit to be driven; a power conversion unit which is connected between the power supply unit and the motor, to generate an alternating current for driving the motor, and includes a DC-link capacitor and an inverter; and an emergency power unit which is connected to the power conversion unit by a switch, to receive power from the power conversion unit to store the same or supply power to the power conversion unit.

Description

Power supply apparatus for driving a motor and a method for controlling the same

The present invention relates to a power supply device, and more particularly, to a power supply device for driving a motor for driving a device that operates with a human, such as a cooperative robot, and a method for controlling the same.

General industrial robots are widely used in production lines to perform precise tasks without human motion or supervision. For example, robots used in the automobile industry perform various tasks such as transporting and welding the body of a vehicle.

Unlike general industrial robots, intelligent service robots perform tasks within the space where people live and work. In particular, cooperative robots that interact with humans require stable power supply.

In this way, when a cooperative robot operating with a person is emergency stopped due to a sudden power accident while driving, the motor stops in a situation where safety is not secured, so that the person working together may be harmed.

Examples of such a sudden power accident may include damage to a power line, a power outage, an instability of a system power source (voltage/frequency fluctuation), and separation of a power cord due to some external situation.

When a power supply accident occurs during the operation of the robot or cooperative robot, it may not be possible to drive the robot to a safe area during emergency operation using only the energy of the normal power supply device.

For example, when a power accident occurs, there is no other option than to stop the motor, so there may be a situation in which damage to a person may occur, such as a part of a person's body being caught by the robot or a heavy object floating in the air.

Therefore, in case of a power accident, it is required to configure the power supply so that the robot can be operated in a safe area or in an emergency operation.

The technical problem to be solved is a power supply for driving a motor to ensure functional safety in the event of a sudden accident situation in the power supply to drive the motor, such as a power accident (blackout and cable burnout) supplied to the inverter for driving the motor. An object of the present invention is to provide an apparatus and a method for controlling the same.

In addition, when the device driven by the motor is a robot such as a cooperative robot, a power supply device for driving a motor capable of preventing damage that may occur due to a power accident while the robot is interacting with a human and a control method thereof would like to provide

When a robot, particularly a cooperative robot that operates with a human, makes an emergency stop due to a sudden power accident while driving, the motor stops in a situation where safety is not ensured, and thus it may cause damage to the person working together.

Examples of such a sudden power accident may include damage to a power line, a power outage, an instability of a system power source (voltage/frequency fluctuation), and separation of a power cord due to some external situation.

According to the present invention, human safety can be ensured by providing a power supply device capable of preventing damage that may occur due to a power supply accident while the cooperative robot is interacting with a human, and a control method thereof.

During normal operation of the power device, the motor is driven through the power conversion unit including the inverter using energy supplied from the power source, but some energy during the initial operation may be used for charging the emergency power unit for emergency driving. The energy used at this time can only use a part that does not affect the normal operation of the robot. The power conversion unit and the emergency power unit may be connected through a switch, and the switch may be opened or closed according to the charging state of the emergency power unit.

At this time, whether a power accident has occurred can be determined using the voltage of the DC link capacitor (DC-link capacitor) in the power conversion unit for driving the motor, and for this, an additional circuit configuration is not required. When the voltage of the DC-link capacitor falls below a certain level, it is determined as a power accident and the switch connected to the emergency power supply can be operated. Emergency operation can be performed.

As a specific example, the present invention provides a power supply device for driving a motor, comprising: a motor connected to a power supply and driven; a power converter connected between the power supply and the motor to generate an alternating current for driving the motor, the DC-power converter including a link capacitor and an inverter; and an emergency power unit connected to the power conversion unit by a switch to receive and store power from the power conversion unit or supply power to the power conversion unit.

In addition, when the power supply is cut off, the power stored in the emergency power supply may be supplied to the power converter.

In addition, the emergency power unit may supply power for a safe stop operation of the robot.

In addition, the emergency power supply unit, a battery for storing the power; a converter connected between the battery and the power converter; and a controller for controlling at least one of the switch, the battery, and the converter.

Also, the converter may be connected between the power converter and the switch.

In addition, the converter may generate a voltage necessary for a safe stop operation of the robot by using the power of the battery.

In addition, the controller may control the converter so that, when a power accident occurs, the voltage of the DC-link capacitor is equal to or greater than a preset reference voltage.

In addition, whether the power accident has occurred may be determined by measuring the voltage of the DC-link capacitor.

In addition, when the power accident occurs, the control unit may determine the state of charge of the battery to control the on/off of the switch.

In addition, the power converter may further include a power regenerative part connected between the DC-link capacitor and the inverter.

As a specific example, the present invention provides a motor connected to and driven by a power supply, a DC-link capacitor and an inverter connected between the power supply and the motor to generate an alternating current for driving the motor, a power conversion unit including an inverter, and an emergency power source provided with a converter and a battery connected to the power conversion unit by a switch, comprising: opening the switch and charging the emergency power source when the power conversion unit is operated; determining whether a power failure occurs by measuring the voltage of the DC-link capacitor; When it is determined that the power accident has occurred, closing the switch and supplying the power charged to the emergency power supply to the power converter.

In addition, the supplying to the power converter may generate a voltage required for a safe stop operation of the robot using the power of the battery.

In addition, the step of supplying the power to the converter, closing the switch; performing emergency driving of the motor by driving the converter; And it may include the step of determining that the operation of the robot is located in a safe area.

In addition, the performing of the discharge control may control the converter so that the voltage of the DC-link capacitor is equal to or greater than a preset reference voltage.

The method may further include controlling charging of the battery when it is determined that the power accident has not occurred.

In addition, the controlling the charging of the battery may include: measuring a voltage of the battery; determining whether the battery needs charging; and closing the switch and charging the battery or opening the switch.

According to the present invention, there are the following effects.

First, in the process of controlling devices such as robots by driving the servo motor, any power accident (damage of the power line, power outage, instability of system power (voltage/frequency fluctuation), power cord separation due to any external situation, etc.) ), it may be possible to drive for a certain period of time or longer.

Accordingly, as an example, damage that may occur due to a power supply accident while the cooperative robot is interacting with a person can be prevented, thereby ensuring human safety.

1 is a block diagram illustrating an example of a power supply device for driving a motor during normal operation.
2 is a block diagram illustrating an example of a power supply device for driving a motor when a power accident occurs.
3 is a circuit diagram showing an example of a power supply device for driving a motor.
4 is a block diagram illustrating a first operation of a power supply device for driving a motor according to an embodiment of the present invention.
5 is a block diagram illustrating a second operation of a power supply device for driving a motor according to an embodiment of the present invention.
6 is a block diagram illustrating a third operation of a power supply device for driving a motor according to an embodiment of the present invention.
7 is a circuit diagram illustrating a power supply device for driving a motor according to an embodiment of the present invention.
8 is a circuit diagram illustrating an emergency power supply of a power supply device for driving a motor according to an embodiment of the present invention.
9 is a circuit diagram illustrating an operation state of an emergency power unit of a power supply device for driving a motor according to an embodiment of the present invention.
10 is a flowchart illustrating a control method of a power supply device for driving a motor according to an embodiment of the present invention.

Hereinafter, the embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but the same or similar components are assigned the same reference numerals regardless of reference numerals, and overlapping descriptions thereof will be omitted. The suffixes "module" and "part" for the components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have a meaning or role distinct from each other by themselves. In addition, in describing the embodiments disclosed in the present specification, if it is determined that the detailed description of the related known technology may obscure the gist of the embodiment disclosed in the present specification, the detailed description thereof will be omitted. In addition, it should be noted that the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and should not be construed as limiting the technical spirit disclosed herein by the accompanying drawings.

Furthermore, although each drawing is described for convenience of description, it is also within the scope of the present invention that those skilled in the art implement other embodiments by combining at least two or more drawings.

It is also understood that when an element, such as a layer, region, or module, is referred to as being “on” another element, it may be directly on the other element or intervening elements may exist in between. There will be.

1 is a block diagram illustrating an example of a power supply device for driving a motor during normal operation, and FIG. 2 is a block diagram illustrating an example of a power supply device for driving a motor when a power accident occurs. 3 is a circuit diagram showing an example of a power supply device for driving a motor.

The power supply device for driving the motor 20 may drive the motor 20 using the power converter 30 connected to the power supply 10 . Here, the power source 10 may be a commercial AC power source. For example, the power supply 10 may be a three-phase AC power supply.

Referring to FIG. 3, the power conversion unit 30 includes a rectifying unit 21 for rectifying the AC power supply 10 and an inverter 23 for outputting a three-phase AC current using the DC power rectified by the rectifying unit 21, And it may include a power regenerative unit 22 including a DC link capacitor (C1) and regenerative circuits (Q1, D1, R1) in which the DC power rectified by the rectifier 21 is charged.

Here, the DC link capacitor C1 is also referred to as a DC-link capacitor C1. Hereinafter, the present invention will be described using the name of the DC-link capacitor C1. In addition, the power conversion unit 30 including the inverter 23 will be described in detail later.

1 shows the flow of power (energy) during normal operation. During normal operation of the power supply device, the power converter 30 generates AC power having an appropriate frequency by using the power of the AC power supply 10 to drive the motor 20 .

However, when a power supply accident occurs, as shown in FIG. 2 , the AC power supply 10 may be lost or the motor 20 may be broken or disconnected.

For example, when a power supply accident occurs, the power conversion unit 30 loses energy (power) capable of driving the motor 20 , so that the driving of the motor 20 is stopped.

At this time, if the motor 20 is suddenly stopped, a big problem may occur depending on the operation of the motor 20 . For example, if the motor 20 is a motor that operates together with a person or operates to drive a cooperative robot operated by a person, a sudden stop of the motor may cause great damage to a person.

On the other hand, when a failure occurs or a disconnection occurs in the motor 20 , the motor 20 may abruptly stop. In this case, the power conversion unit 30 detects the stop of the motor 20 and stops the power transmission, but the already transferred power (energy) cannot be transmitted to the motor 20 , so the circuit of the power conversion unit 30 is may cause damage.

For example, a current that cannot be transmitted to the motor 20 may damage the DC-link capacitor C1 or damage the switching element included in the inverter 23 .

As such, when a failure occurs or a disconnection occurs in the motor 20 , the current not transmitted to the motor 20 may return to the DC-link terminal as indicated by the arrow in FIG. 3 . At this time, the regenerative circuits Q1 , D1 , and R1 can prevent the power converter 20 from being damaged due to the current that is not transmitted to the motor 20 (hereinafter referred to as a return current).

For example, the circuit may be connected so that the switch element Q1 of the regenerative circuit operates so that the return current passes through the resistor R1. This resistor R1 can consume power due to the return current as heat, and is also called a chopper resistor.

That is, when such a return current occurs, the voltage of the DC-link capacitor C1 may increase more than necessary, and at this time, the chopper resistor R1 consumes the power of the DC-link capacitor C1. can

For example, as the chopper resistor R1, a resistor having a very large size and capacity to sufficiently consume the return current may be used.

As such, if the motor 20 is suddenly stopped when a power accident occurs, a large problem may occur depending on the operation of the motor 20 . In addition, a regenerative circuit including a resistor R1 having a very large size and capacity may be provided in order to prepare for a case in which a return current occurs due to a failure of the motor 20 or the like.

4 is a block diagram illustrating a first operation of the power supply device for driving a motor according to an embodiment of the present invention, and FIG. 5 is a block diagram illustrating a second operation of the power supply device for driving a motor according to an embodiment of the present invention. am. 6 is a block diagram illustrating a third operation of a power supply device for driving a motor according to an embodiment of the present invention.

4 to 6 , the power device for driving the motor 200 may drive the motor 200 using the power converter 300 connected to the power source 100 . Here, the power source 100 may be a commercial AC power source. For example, the power source 100 may be a three-phase AC power source. In addition, the emergency power supply unit 400 capable of emergency driving the motor 200 in the event of a power accident may be connected to the power conversion unit 300 . The emergency power unit 400 may be connected to the input terminal of the power conversion unit 400 through the switch S1.

The emergency power unit 400 may be connected to the power conversion unit 300 by the switch S1 to receive and store power from the power conversion unit 300 or supply power to the power conversion unit 300 .

The switch S1 may be a relay switch operated by the controller 430 (refer to FIG. 8 ). That is, the switch S1 may operate according to the state of the power supply unit 100 or the state of the emergency power supply unit 400 . The emergency power unit 400 may charge and discharge power.

For example, referring to FIG. 4 , although the power supply is operating normally, when the emergency power unit 400 is not partially or fully charged, the switch S1 is closed (On) and some of the power of the power supply unit 100 is turned on. can be used to charge the emergency power unit 400 .

As such, during normal operation of the power device, the motor 200 is driven through the power conversion unit 300 using the energy supplied from the power supply unit 100, but some of the energy during the initial operation is transferred to the emergency power supply unit for emergency driving ( 400) can be used for charging. In this case, the energy used may use only a part that does not affect the normal operation of the device driven by the motor 200 , for example, the robot.

Thereafter, when the emergency power supply unit 400 is fully charged while the power supply is operating normally, that is, when the emergency power supply unit 400 is fully charged, as shown in FIG. 5 , the switch S1 is opened (Off) ) can be disconnected from the power converter 300 to prevent unnecessary energy consumption.

On the other hand, referring to FIG. 6 , when a power accident, for example, an accident of the power supply unit 100 occurs, the switch S1 is closed (On) and the energy (power) stored in the emergency power supply unit 400 is used to operate the motor It is possible to perform an emergency drive of 200 .

In this case, whether a power accident occurs may be determined using the DC link voltage of the power converter 300 . For example, an accident of the power supply unit 100 may be determined by using the voltage of the DC link (DC-link) capacitor C1.

As mentioned above, when a power supply accident occurs, the power converter 300 loses energy (power) capable of driving the motor 200 , so that the driving of the motor 200 may be stopped.

At this time, if the motor 200 is suddenly stopped, a big problem may occur depending on the operation of the motor 200 . For example, if the motor 200 is a motor that operates together with a person or operates to drive a cooperative robot operated by a person, a sudden stop of the motor may cause great damage to a person.

Accordingly, it is possible to prevent the motor 200 from suddenly stopping by using the power charged in the emergency power supply unit 400 . For example, in the event of a power accident, the power converter 300 loses energy (power) capable of driving the motor 200 , so that the driving of the motor 200 may be stopped.

Accordingly, if the motor 200 is suddenly stopped, a big problem may occur depending on the operation of the motor 200 . For example, if the motor 200 is a motor that operates together with a person or operates to drive a cooperative robot operated by a person, a sudden stop of the motor may cause great damage to a person.

However, it is possible to prevent the motor 200 from abruptly stopping by using the power charged in the emergency power supply unit 400 , and for example, it is possible to supply power to the cooperative robot to return to a stable area.

7 is a circuit diagram illustrating a power supply device for driving a motor according to an embodiment of the present invention.

Referring to FIG. 7 , the motor 200 is connected to the power supply unit 100 and driven, and it is connected between the power supply unit 100 and the motor 200 to generate an alternating current for driving the motor 200, DC- The power conversion unit 300 including the link capacitor C1 and the inverter 340 and the power conversion unit 300 are connected to the power conversion unit 300 by the switch S1 to receive and store power from the power conversion unit 300 or power It may be configured to include an emergency power supply unit 400 for supplying power to the conversion unit 300 .

The power converter 300 may further include a rectifier 310 for rectifying the AC power source 100 . Accordingly, the power converter 300 may include an inverter 340 that outputs a three-phase alternating current, and a DC-link (DC-stage) capacitor C1 between the rectifier 310 and the inverter 340 .

In some cases, a converter for boosting/stepping down the DC voltage rectified by the rectifying unit 310 or controlling the power factor may be further provided between the rectifying unit 310 and the DC-link capacitor C1 (not shown).

The inverter 340 outputs a three-phase alternating current, and this output current is supplied to the motor M 200 . Here, the motor 200 may be a servo motor for driving the robot, as mentioned above. Accordingly, the power converter 300 may be provided in the robot. However, the present invention is not limited thereto.

Hereinafter, it will be described as an example that the motor 200 is a servo motor for driving the robot, and the power converter 300 is a motor driving device for driving a servo motor driving the robot.

However, the motor 200 is not limited to a servo motor, and may be used in various application products using a frequency-variable AC voltage, for example, AC motors such as refrigerators, washing machines, electric vehicles, automobiles, and vacuum cleaners.

The power converter 300 receives AC power from the system, converts the power, and supplies the converted power to the motor 200 .

The rectifying unit 310 receives and rectifies the AC power 100 , and outputs the rectified power to the DC-link capacitor C1 side. To this end, the rectifier 310 may use a full-wave rectification circuit using a bridge diode.

Meanwhile, although not shown, the power converter 300 may further include various sensing units such as a DC terminal voltage detector, an input voltage detector, an input current detector, an output current detector, and the like.

The input voltage detector may detect an input voltage from the input AC power source 100 . For example, it may be located in front of the rectifying unit 310 .

The input voltage detector may include a resistance element, an OP AMP, and the like for voltage detection. The detected input voltage, as a discrete signal in the form of a pulse, may be applied to the controller 430 to generate a control signal of the inverter 340 .

Next, the input current detector may detect the input current from the input AC power source 100 . Specifically, it may be located in front of the rectifying unit 310 .

The input current detector may include a current sensor, a current transformer (CT), a shunt resistor, and the like for current detection. The detected input current, as a discrete signal in the form of a pulse, may be applied to the controller 430 to generate an inverter control signal.

The DC voltage detection unit may detect a pulsating voltage of the DC-link capacitor C1. For this power detection, a resistive element, an OP AMP, etc. may be used. The detected voltage of the DC-link capacitor C1 may be applied to the controller 340 as a discrete signal in the form of a pulse, and an inverter control signal based on the DC voltage of the DC-link capacitor C1 can be created.

The inverter 340 includes a plurality of inverter switching elements Qa, Qb, Qc, Qa', Qb', and Qc', and provides a three-phase alternating current with a predetermined frequency to a DC power supply smoothed by on/off operation of the switching elements. It can be converted into power and output to the three-phase servo motor 200 .

Specifically, the inverter 340 is a pair of upper-arm switching elements (Qa, Qb, Qc) and lower-arm switching elements (Qa', Qb', Qc') connected in series with each other, and a total of three pairs of upper/lower arm switching The elements may be connected in parallel with each other.

The switching elements Qa, Qb, Qc, Qa', Qb', and Qc' of the inverter 340 may use a power transistor, for example, an insulated gate bipolar mode transistor (IGBT). Available.

The emergency power unit 400 may be connected between the output terminal of the rectifier 310 and the ground terminal by the switch S1. Here, the emergency power supply 400 including the switch S1 will be described as the emergency power supply 401 .

Meanwhile, the power conversion unit 300 may further include a power regeneration unit 330 connected between the DC-link capacitor C1 and the inverter 340 .

The power regeneration unit 330 may prevent the circuit from being damaged due to a current (return current) that is not transmitted to the motor 200 when a failure occurs or a disconnection occurs in the motor 200 .

For example, a circuit may be connected such that the switch element Q1 of the power regeneration unit 330 operates so that the return current passes through the resistor R1 . The resistor R1 may consume power due to the return current as heat. In this case, the diode D1 may set a path so that the return current flows to the resistor R1.

Meanwhile, when the emergency power supply unit 400 according to the present invention is provided, the power regeneration unit 330 may be omitted.

8 is a circuit diagram illustrating an emergency power supply of a power supply device for driving a motor according to an embodiment of the present invention.

Referring to FIG. 8 , the emergency power unit 400 includes a battery 420 for storing (charging) power, a converter 410 connected between the battery 420 and the power conversion unit 300 , and a switch S1 . ), the battery 420 and the converter 410 may include a control unit 430 for controlling at least one.

The controller 430 may control the power converter 300 together as described above. That is, the power converter 300 may control at least one of the DC-link capacitor C1 and the inverter 340 . However, in some cases, a separate control unit may control the power converter 300 of course. In this embodiment, an example in which the control unit 430 of the emergency power unit 400 controls the power conversion unit 300 together will be described.

Referring to FIG. 8 , arrows a, b, c and d show the flow of signals exchanged between the controller 430 of the emergency power unit 400 and the emergency power unit 400 .

As described above, the controller 430 may detect the voltage of the DC-link capacitor C1. This is indicated by an arrow 'a', and the detection of the voltage of the DC-link capacitor C1 may be performed through the above-mentioned DC voltage detection unit. However, it is not limited thereto.

Also, the controller 430 may control opening/closing (on/off; On/Off) of the switch S1 . This is indicated by an arrow 'b', and this switch S1 may be a relay switch operated by the controller 430 . That is, it may be a switch that is turned on/off as the controller 430 applies a current to the coil.

Meanwhile, the controller 430 may control the converter 410 . This is indicated by arrow 'c'. The converter 410 may emergency drive the motor 200 using the power of the battery 420 . As an example, it is possible to generate a voltage (power) required for a safe stop operation of the robot.

In this case, the controller 410 may control the converter 410 so that, when a power accident occurs, the voltage of the DC-link capacitor C1 is equal to or greater than a preset reference voltage.

The converter 410 may output power of a constant voltage by using the power of the battery 420 . The converter 410 may use a direct current-direct current (DC-DC) converter. In addition, the DC-DC converter may use a boost converter or a step-down converter (Buck converter).

The illustration of the specific configuration of such a converter is omitted. However, the switching element of the converter 410 may perform a switching operation by a separate pulse width modulation (PWM) signal. That is, the PWM signal transmitted from the controller 430 through the path 'c' is connected to the switching element of the converter 410, and a switching operation can be performed by the PWM signal.

In this way, the controller 430 may control the turn-on timing of the switching element in the converter 410 . Accordingly, the controller 430 may output a converter control signal for the turn-on timing of the switching element of the converter 410 . Under the control of the controller 430 , the converter 410 may convert the voltage of the battery 420 into a constant voltage and output the converted voltage.

The controller 430 may sense the voltage of the battery 420 . This is indicated by the 'd' path. The controller 430 may control the converter 410 so that the voltage of the DC-link capacitor C1 is equal to or greater than a preset reference voltage during emergency operation, and in this case, the voltage level of the battery 420 may be measured. .

As such, the control unit 430 of the emergency power unit 400 may determine whether an abnormality has occurred in a power accident by specifying the voltage of the DC-link capacitor C1.

In this case, the control unit 430 of the emergency power unit 400 may measure the voltage of the battery 420 to determine the charging state of the emergency power unit 400 .

In addition, the control unit 430 of the emergency power unit 400 may determine whether the switch S1 is opened or closed by determining the state of charge of the emergency power unit 400 and whether a power accident has occurred or whether the power is cut off.

As such, the control unit 430 of the emergency power unit 400 may determine the charging state of the emergency power unit 400 and whether a power accident has occurred to open the switch S1 and operate the converter 410 . That is, the controller 430 may generate a PWM control signal of the converter 410 and transmit it to the converter 410 .

In this case, the controller 430 may control the converter 410 so that, when a power accident occurs, the voltage of the DC-link capacitor C1 is greater than or equal to a preset reference voltage.

That is, when a power accident occurs, the control unit 430 may supply power so that the voltage of the DC-link capacitor C1 can perform a safe stop operation of the robot.

When a robot, particularly a cooperative robot that operates with a human, makes an emergency stop due to a sudden power accident while driving, the motor stops in a situation where safety is not ensured, and thus it may cause damage to the person working together.

Examples of such a sudden power accident may include damage to a power line, a power outage, an instability of a system power source (voltage/frequency fluctuation), and separation of a power cord due to some external situation.

According to the present invention, human safety can be ensured by providing a power supply device capable of preventing damage that may occur due to a power supply accident while the cooperative robot is interacting with a human, and a control method thereof.

During normal operation of the power supply, the motor 200 is driven through the power conversion unit 300 including the inverter 340 using energy supplied from the power source, but some of the energy during the initial operation is transferred to the emergency power supply unit for emergency driving. It can be used for the filling of 400. The energy used at this time can only use a part that does not affect the normal operation of the robot. The power conversion unit 300 and the emergency power unit 400 may be connected through the switch S1 , and the switch S1 may be opened or closed according to the charging state of the emergency power unit 400 .

In this case, whether a power accident has occurred may be determined using the voltage of the DC-link capacitor C1 in the power conversion unit for driving the motor, and for this purpose, an additional circuit configuration may not be required. When the voltage of the DC-link capacitor C1 is below a certain level, it is determined as a power accident and the switch S1 to which the emergency power unit 400 is connected can be operated, and accordingly, the emergency power unit 400 is charged The (stored) energy (power) can be used to perform emergency operation of the robot.

9 is a circuit diagram illustrating an operation state of an emergency power unit of a power supply device for driving a motor according to an embodiment of the present invention.

In fact, when a power accident occurs, as shown in FIG. 9 , the power supply unit 100 and the rectifier unit 310 may be substantially disconnected from the DC-link capacitor C1 .

In addition, the switch S1 is turned on, and the emergency power supply unit 400 or the emergency power supply unit 401 including the switch S1 and the emergency power unit 400 is connected to both ends of the DC-link capacitor C1. state can be

10 is a flowchart illustrating a control method of a power supply device for driving a motor according to an embodiment of the present invention.

Hereinafter, an operation process of a power supply device for driving a motor according to an embodiment of the present invention will be described in detail with reference mainly to FIGS. 9 and 10 . In this case, reference may be made to FIGS. 7 and 8 together.

First, when the motor 200 is driven, input power may be initially supplied. When the normal operation of the power supply device starts, the power converter 300 may drive the motor 200 by generating AC power having an appropriate frequency using the power of the AC power source 100 . At this time, at the same time, the emergency power unit 400 may be charged together (S10). At this time, the switch S1 may be in a closed state (On).

The charging operation of the emergency power unit 400 may be performed until charging is completed. That is, it is determined whether charging is complete (S20), and when charging is completed, charging of the emergency power unit 400 may be stopped.

At this time, it is determined that the preparation for driving the motor 200 is completed, and the motor may be driven (S30). That is, the switch S1 is in an open state (Off), and the power of the AC power source 100 is not transmitted to the emergency power unit 400 side but only to the power conversion unit 300 side so that the motor 200 is driven. can

In this way, in the process of driving the motor 200, the controller 430 may measure the DC link voltage (S30). For example, the controller 430 may measure the voltage of the DC-link capacitor C1. The DC link voltage may be measured periodically or continuously.

Through the DC link voltage measurement (S30), the control unit 430 can determine whether a power accident has occurred (S50).

In this case, if it is determined that a power accident has occurred, an operation of closing the switch S1 and supplying the power charged in the emergency power unit 400 to the power conversion unit 300 may be performed (S70).

On the other hand, if it is determined that a power accident has not occurred, an operation ( S60 ) of controlling the charging of the battery 420 may be performed.

First, the operation (S70) of supplying the power charged in the emergency power unit 400 to the power conversion unit 300 will be described in detail.

As mentioned above, whether a power accident has occurred may be determined by determining the measured voltage of the DC-link capacitor C1. In this case, for example, if the measured voltage of the DC-link capacitor C1 is less than or equal to a reference value, it may be determined that a power accident has occurred.

Also, in addition to this, it may be further determined whether the measured voltage of the DC-link capacitor C1 continues or further decreases. That is, if the measured voltage of the DC-link capacitor C1 is smaller than the reference value but does not continuously or additionally fall, it is determined that a power accident has not occurred and the operation S60 of controlling the charging of the battery 420 may be performed. .

On the other hand, if the measured voltage of the DC-link capacitor C1 is smaller than the reference value, and continues or further falls, it is determined that a power accident has occurred and the power charged in the emergency power unit 400 is supplied to the power conversion unit 300 . (S70) may be performed.

If it is determined that a power accident has occurred, the step of supplying power to the power converter (S70) may include closing (On) the switch S1 and performing a discharge control process of the battery 420 (S71).

As such a discharge control process, the controller 430 may perform an emergency driving operation for stabilizing the motor 200 using the power of the battery 420 (S72). As an example, a voltage required for a safe stop operation of the robot may be generated.

That is, the operation (S70) of supplying the power charged in the emergency power supply unit 400 to the power conversion unit 300 includes closing the switch (S71) and driving the converter 410 to perform emergency driving of the motor 200. It may include a step (S72) of performing and a step (S3) of determining that the operation of the motor 200 is located in a safe area.

In addition, performing the emergency driving ( S72 ) may control the converter 410 so that the voltage of the DC-link capacitor C1 is greater than or equal to a preset reference voltage.

As an example, the motor 200 may drive up to a safe section in the operating area and perform emergency driving of the motor to stop the driving after confirming that there is no abnormality ( S71 and S72 ).

An example of emergency driving is a case in which power is cut off while the cooperative robot is carrying a heavy object. At this time, since there is a risk of a safety accident when the object falls on the way, it may be necessary to lower the height of the object as much as possible or to put the object down. Accordingly, the emergency power unit 400 may supply power to the power conversion unit 300 as the emergency driving is stably performed.

Another example of emergency driving may be a case in which the power of the cooperative robot is cut off while interacting with a human body such as a human hand. When such a case occurs, the robot notifies a person that the current operation is an emergency drive, and performs an emergency operation to prevent the human body from being restrained or caught, thereby ensuring human safety.

Meanwhile, as described above, when it is determined that a power accident has not occurred, an operation S60 of controlling the charging of the battery 420 may be performed.

In the step (S60) of controlling the charging of the battery 420 as described above, the step of measuring the voltage of the battery 420 (S61) and the step (S62) of determining whether charging of the battery 420 is necessary are performed first. can

Accordingly, when it is determined that the battery 420 needs to be charged, the switch S1 is closed (On) and a process S63 of charging the battery 420 may be performed.

Thereafter, when it is determined that the battery 420 is sufficiently charged, the switch S1 may be opened ( S64 ).

As described above, according to the embodiment of the present invention, in the process of controlling a device such as a robot by driving a servo motor, any power accident (damage of power line, power outage, instability of system power (voltage/frequency fluctuation) ), power cord disconnection due to any external circumstances, etc.) may be possible to drive for a certain period of time or longer.

Accordingly, as an example, damage that may occur due to a power supply accident while the cooperative robot is interacting with a person can be prevented, thereby ensuring human safety.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains.

Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments.

The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

100: power supply (input power) 200: motor
300: power conversion unit 400: emergency power unit
410: converter 420: battery
430: control unit

Claims (16)

In the power supply device for driving a motor,
a motor connected to the power supply and driven;
a power converter connected between the power supply and the motor to generate an alternating current for driving the motor, the DC-power converter including a link capacitor and an inverter; and
and an emergency power supply connected to the power converter by a switch to receive and store power from the power converter or supply power to the power converter. The power supply device for driving a motor according to claim 1, wherein the power stored in the emergency power supply is supplied to the power converter when the power supply is shut off. The power supply device for driving a motor according to claim 1, wherein the motor is a motor for driving the robot, and the emergency power unit supplies power for a safe stop operation of the robot. The method of claim 3, wherein the emergency power supply unit,
a battery for storing the power;
a converter connected between the battery and the power converter; and
and a control unit for controlling at least one of the switch, the battery, and the converter. The power supply device for driving a motor according to claim 4, wherein the converter is connected between the power converter and the switch. The power supply device for driving a motor according to claim 4, wherein the converter generates a voltage necessary for a safe stop operation of the robot by using the power of the battery. The power supply device for driving a motor according to claim 4, wherein the controller controls the converter so that, when a power accident occurs, the voltage of the DC-link capacitor is equal to or greater than a preset reference voltage. The power supply device for driving a motor according to claim 7, wherein the occurrence of the power accident is determined by measuring the voltage of the DC-link capacitor. The power supply device for driving a motor according to claim 7, wherein, when the power accident occurs, the control unit determines the state of charge of the battery and turns the switch on/off. The power supply device for driving a motor according to claim 1, wherein the power conversion unit further comprises a power regeneration unit connected between the DC-link capacitor and the inverter. A motor connected to a power source to be driven, a power conversion unit including a DC-link capacitor and an inverter as being connected between the power source and the motor to generate an alternating current for driving the motor, and the power conversion unit by a switch In the control method of a power supply device comprising an emergency power unit provided with a battery and a converter connected to,
opening the switch and charging the emergency power supply when the power converter is operated;
determining whether a power failure occurs by measuring the voltage of the DC-link capacitor;
When it is determined that the power accident has occurred, closing the switch and supplying the electric power charged in the emergency power supply to the power converter. The method of claim 11 , wherein the supplying to the power converter comprises generating a voltage required for a safe stop operation of the robot using the power of the battery. The method of claim 12, wherein the supplying to the power converter comprises:
closing the switch;
performing emergency driving of the motor by driving the converter; and
and determining that the robot is located in a safe area. The method of claim 13 , wherein in the performing of the discharge control, the converter is controlled so that the voltage of the DC-link capacitor is equal to or greater than a preset reference voltage. The method of claim 11 , further comprising: controlling charging of the battery when it is determined that the power accident has not occurred. The method of claim 15, wherein the controlling of the charging of the battery comprises:
measuring the voltage of the battery;
determining whether the battery needs charging; and
and closing the switch and charging the battery or opening the switch.

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