JP4367341B2 - Dynamic brake circuit protection device - Google Patents

Description

  The present invention relates to a dynamic brake (hereinafter referred to as DB) circuit provided in a motor control device, and relates to a protection device for preventing the DB circuit from being broken.

  Conventionally, servo motors are often used in FA system devices such as semiconductor manufacturing devices, robots, and various machine tools. In these FA fields, it is necessary to urgently stop the movable part in order to destroy the device or to ensure safety when an abnormality occurs. Generally, the servo motor control device has a built-in DB circuit.

  FIG. 6 shows a configuration diagram of a servo motor control device incorporating a DB circuit. The DB circuit 61 includes a rectifier diode 66, a relay 67, and a DB resistor 68. The DB electromotive force generated when the servo motor 5 rotates is rectified by the rectifier diode 66, and the DB resistor 68 is made conductive through the relay 67. Thus, the brake torque is generated, and the energy of the back electromotive force is converted into heat energy by the DB resistor 68 and is consumed and stopped. Further, by using the B contact type that conducts the relay 67 used in the DB circuit 61 when it is not excited, it is possible to perform an emergency stop even when the power supply is shut off due to a power failure or the like.

The capability of the DB circuit 61 is limited by the current capacity of the relay 67 and the allowable power of the DB resistor 68. However, there is a method for protecting the DB circuit 61 from destruction by monitoring the power consumption and the current value with the control means 10. It has been devised (see, for example, Patent Document 1 and Patent Document 2).
JP 2002-369564 A JP-A-8-33195

  However, when the power is not supplied to the motor controller and the servo motor is turned from the outside, the DB resistor consumes the energy generated by the servo motor because the relay is in a conductive state. If the capacity of the DB resistor is exceeded, it will be destroyed. In such an abnormal state, the protection circuit described above does not operate and the DB circuit cannot be protected.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to provide a motor control device that can protect a DB circuit even in an abnormal state in which the motor is rotated by an external force with the power off. To do.

In order to solve the above problems, the present invention has a dynamic brake circuit in which a DB resistor is connected in parallel to a DB rectifier circuit connected to a motor via a relay, and the motor is urgently stopped by closing the contact of the relay. In the motor control device to be connected , the power source for control is generated from the counter electromotive force generated when the motor is rotated from the outside , connected to the DB rectifier circuit, and relayed when power is supplied to the motor control device DB control power generation means having a diode for shutting off the power supply, DB abnormality detection means connected to the DB rectifier circuit for detecting abnormality of the dynamic brake circuit by voltage division , and DB control power generation means It is connected, and a DB control unit for opening said relay receiving DB abnormal signal from the DB abnormality detecting means, the DB control Stage, the motor startup after the power ON and open excited the relay by a relay power supply, when at receiving the DB abnormality signal power OFF is energized the relay via the diode of the DB control power generation unit Then, the DB rectifier circuit and the DB resistor are made non-conductive. Further, a temperature detection element is used as the DB abnormality detection means.

According to the dynamic brake circuit protection device of the present invention, the DB circuit can be protected even in an abnormal state where the motor is rotated by an external force.

In a motor control device having a dynamic brake circuit in which a DB resistor is connected in parallel to a DB rectifier circuit connected to a motor via a relay, and closing the contact of the relay to urgently stop the motor, the DB rectifier circuit includes A DB that has a diode that is connected and generates a control power source from the back electromotive force generated when the motor is rotated from the outside and shuts off the relay power source when power is supplied to the motor control device Control power generation means, DB abnormality detection means connected to the DB rectifier circuit for detecting abnormality of the dynamic brake circuit by voltage division, DB abnormality detection means connected to the DB control power supply generation means, and DB from the DB abnormality detection means receiving an abnormality signal and a DB control means for opening the relay, the DB control unit, the motor startup after power oN Opened by energizing the relay by a relay power supply, when at receiving the DB abnormality signal power OFF is opened by energizing the relay via the diode of the DB control power generation unit, the DB rectifying circuit a DB resistor is dynamic braking circuit protection device comprising a to Turkey nonconductive.

  A dynamic brake circuit protection device according to the present invention will be described with reference to FIGS. 1, 2, and 3.

  FIG. 1 is a configuration diagram of a servo motor control device incorporating a dynamic brake circuit protection device according to the first embodiment.

  The power supply 1 is often single-phase or three-phase 100V and 200V specifications. The rectifier diode 2 converts the power supply 1 to DC and the electrolytic capacitor 3 removes the ripple component. Recently, a device may be configured with a low voltage for miniaturization, and a DC power source with a low voltage such as DC24V may be used. In such a servo motor control device, a rectifier diode can be omitted. .

  Since the inverter circuit 4 is composed of a three-phase full bridge circuit, it is composed of six IGBTs. The servo motor 5 is generally a permanent magnet AC servo motor, and each winding is supplied with a voltage from the inverter circuit 4 and is applied with a sinusoidal voltage by PWM control (Pulse width modulation).

  Next, the configuration of the dynamic brake circuit protection device will be described. The dynamic brake circuit protection device 11 includes a DB control power generation unit 15, a DB control unit 16, and a DB abnormality detection unit 17 in addition to the DB circuit (DB rectifier circuit 6, relay 7, DB resistor 8) similar to the conventional one. Is done. Although the DB resistor 8 depends on the capacity of the servo control device, a resistor of several Ω to several tens of Ω is used. The DB circuit 11 is used when it is desired to urgently stop the servo motor in the event of an abnormality, and the principle is as follows.

  When the servo motor 5 rotates, AC energy called back electromotive force is generated in the winding, and the DB rectifier circuit 6 converts this energy into DC energy. Since the relay 7 is connected to the positive side and the negative side of the DB rectifier circuit 6 via the DB resistor 8, all the energy generated from the servo motor 5 is applied to the DB resistor 8 and consumed. The servo motor 5 is caused to generate a brake torque by operating to make the energy zero, and the servo motor 5 stops.

  This relay 7 has a B contact, and the DB resistor 7 is in a conducting state when the power is turned off, and is brought into a non-conducting state when the servo motor 5 is started after the power is turned on. It is also possible to set parameters so that the servo motor 5 is turned off even when the servo motor 5 is not started after the power is turned on by setting the control device.

  The relay power supply 19 is generated by the DCDC power supply circuit 9 in order to insulate it from the power supply 1, and is often designed to output 12V as a power supply for driving the relay.

  Here, the operation of the dynamic brake circuit protection device 11 will be described. When the power source 1 is not applied, the relay power source 19 is not generated, so the relay 7 is in a conductive state. At this time, if the servo motor 5 is turned from the outside, a brake torque is generated. As described above, even when the power supply 1 is in the OFF state, the servo motor 5 can be rotated with a larger torque from the outside. In this case, a voltage is generated by the counter electromotive force of the servo motor 5.

  The generated voltage is converted into direct current by the DB rectifier circuit 6, and the converted direct current voltage is applied to the DB control power generation unit 15 to supply power to the relay power supply 19, the DB control unit 16, and the DB abnormality detection unit 17. To do.

  FIG. 2 is an example of a circuit of the DB control power generation unit. Hereinafter, description will be given with reference to FIG. The DB control power generation means 15 includes a DCDC power supply circuit 23 and a diode 24. The DCDC power supply circuit 23 can be constituted by a regulator if the back electromotive force of the servo motor 5 is small and 35 V or less, and if it is more than that, it becomes a configuration such as a switching power supply. In this case, it is insulated from the power supply of the DB rectifier circuit 6 You can also. The diode 24 is provided to shut off the power supply from the DB control power supply generation unit 15 and disable it when power is supplied from the power supply 1 to the servo motor control device 12.

  Next, DB control means and DB abnormality detection means will be described with reference to FIG. The DB abnormality detection means 17 is composed of two resistors 25 and 26 and outputs a DB abnormality signal 18 by dividing the voltage rectified by the DB rectifier circuit 6 by resistance. The DB control means 16 is composed of a buffer IC 36 and uses the voltage supplied from the DB control power generation means 15 as the DB control power supply 22 and receives the DB abnormality signal 18 from the DB abnormality detection means 17.

  A case where the value of the DB abnormality signal 18 exceeds the threshold value of the buffer IC 36 is recognized as an abnormality, and the DB release signal 28 is output. A photocoupler 33 is also connected to the input of the buffer IC 36. When the power supply 1 is normally applied, the DB release signal 34 is output by the control means 10 so that the photocoupler 33 is turned on. , The DB release signal 35 is L level, the buffer IC 36 outputs L, and the DB circuit protection device is not operated.

  When the servo motor rotates when the power supply 1 is not applied, the DB release signal 28 becomes H when the value of the DB abnormal signal 18 exceeds the threshold value of the buffer IC 36, and the transistor 27 is turned ON to relay. 7 can be made non-conductive to prevent the DB resistor 8 and the relay 7 from being destroyed.

  By adopting the configuration as described above, it is possible to prevent the DB resistor and relay of the DB circuit from being damaged even in an abnormal state where the servo motor control device is not supplied with power and the servo motor is being turned from the outside. it can.

  A second embodiment of the present invention will be described with reference to FIGS.

  The difference from the first embodiment is that a temperature abnormality detecting means 31 is provided in the DB abnormality detecting means 17 and a temperature abnormality signal 37 of the temperature detecting means 31 is outputted and inputted to the DB control means 16. Explained.

  As in the first embodiment, when the power source 1 is not applied and the servo motor 5 is rotated from the outside, the relay 7 is conductive, so that all the energy generated by the servo motor 5 is consumed by the DB resistor 8. Is done.

  When the DB resistor 8 exceeds the allowable temperature due to energy consumption, the temperature detection means 31 outputs a temperature abnormality signal 37 that becomes the DB abnormality signal 18 and is input to the control means 16 in order to protect the DB resistor 8. As the temperature detecting means 31, there is a thermal guard OHD made by NEC / Tokin, for example, which is normally switched on, that is, in a conductive state, and when the set temperature is exceeded, the switch is turned off and becomes non-conductive.

  In FIG. 5, when the temperature detecting means 31 becomes non-conductive, the DB abnormality signal 18 becomes H, and the output of the buffer IC 36 also becomes H. At this time, the transistor 27 in FIG. 4 is turned on, the relay 7 is turned off, and the DB resistor 8 is disconnected from the DB rectifier circuit 6.

  It should be noted that the circuit can be easily configured even if another temperature detection element such as a thermistor is used as the temperature detection means.

  With the configuration as described above, the DB resistance can be prevented from being destroyed even in an abnormal state in which no power is supplied to the servo motor control device and the servo motor is rotated from the outside.

  The dynamic brake circuit protection device of the present invention is useful not only for a servo motor control device but also for a motor control device that wants to protect a DB circuit.

1 is an overall configuration diagram of a servo motor control device incorporating a dynamic brake circuit protection device according to a first embodiment of the present invention. Configuration diagram of DB control power generation means in Embodiment 1 of the present invention Configuration diagram of DB control means and DB abnormality detection means in Embodiment 1 of the present invention Overall configuration diagram of a servo motor control device incorporating a dynamic brake circuit protection device in Embodiment 2 of the present invention Configuration diagram of DB control means and DB abnormality detection means in Embodiment 2 of the present invention Configuration diagram of servo motor controller in conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power supply 2 Rectification circuit 3 Electrolytic capacitor 4 Inverter circuit 5 Servo motor 6 DB rectification circuit 7 Relay 8 DB resistor 9, 23 DCDC power supply circuit 10 Control means 11 DB circuit 12 Servo motor control device 14, 33 Photocoupler 15 DB control power supply Generation means 16 DB control means 17 DB abnormality detection means 18 DB abnormality signal 19 Relay power supply 21 Control power supply 22 DB control power supply 24 Diode 25, 26 Resistor 28, 29 DB release signal 31 Temperature detection means 32 Transistor 34, 35 DB release signal 36 Buffer IC
37 Abnormal temperature signal

Claims (2)

In a motor control device having a dynamic brake circuit in which a DB resistor is connected in parallel to a DB rectifier circuit connected to a motor via a relay, and closing the contact of the relay to urgently stop the motor, the DB rectifier circuit includes A DB that has a diode that is connected and generates a control power source from the back electromotive force generated when the motor is rotated from the outside and shuts off the relay power source when power is supplied to the motor control device Control power generation means, DB abnormality detection means connected to the DB rectifier circuit for detecting abnormality of the dynamic brake circuit by voltage division, DB abnormality detection means connected to the DB control power supply generation means, and DB from the DB abnormality detection means receiving an abnormality signal and a DB control means for opening the relay, the DB control unit, the motor startup after power oN Opened by energizing the relay by a relay power supply, when at receiving the DB abnormality signal power OFF is opened by energizing the relay via the diode of the DB control power generation unit, the DB rectifying circuit A dynamic brake circuit protection device, wherein the DB resistor is made non-conductive. The dynamic brake circuit protection device according to claim 1, wherein a temperature detection element is used as the DB abnormality detection means.

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