JP3886323B2 - Electric motor control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric motor control device that has a power supply circuit that suppresses an inrush current when power is turned on and that controls driving of a plurality of electric motors.
[0002]
[Prior art]
In recent years, when a plurality of motors are used, a motor control device configured by connecting a power supply unit and a plurality of drive units has been used.
[0003]
Hereinafter, a conventional motor control device will be described with reference to a circuit diagram.
[0004]
In FIG. 2, the power supply unit 21 of the motor control device receives an AC power supply 22 and rectifies it into a DC voltage, an electrolytic capacitor 24 that smoothes the rectified voltage, and suppresses an inrush current when the power is turned on. Inrush current suppression resistor 25, electromagnetic switch 26 connected in parallel with inrush current suppression resistor 25, main circuit voltage comparison circuit 27 for detecting that the main circuit voltage is equal to or higher than a predetermined voltage, and electromagnetic switch An electromagnetic switch drive circuit 28 that opens and closes 26 contacts is provided, and the power supply unit 21 of the motor control device supplies a main circuit voltage to each drive unit that drives a plurality of motors.
[0005]
In the above configuration, when the AC power supply 22 is turned on, an inrush current for charging the smoothing electrolytic capacitor 24 first flows through the inrush current suppression resistor 25. Thereafter, when the main circuit voltage rises and exceeds a predetermined voltage, the main circuit voltage comparison circuit 27 operates the electromagnetic switch drive circuit 28 and closes the contacts of the electromagnetic switch 26. Thereby, when driving a plurality of motors, the current supplied to the plurality of motors flows through the contacts of the electromagnetic switch 26.
[0006]
[Problems to be solved by the invention]
In the above conventional motor control device, the contact of the electromagnetic switch is closed when the main circuit voltage rises to a predetermined voltage or higher after the AC power is turned on, but the smoothing electrolytic capacitor is not fully charged. Inrush current flows to the contact of the electromagnetic switch at the moment of closing the contact of the switch. Therefore, it is necessary to increase the current capacity of the contact of the electromagnetic switch, and a large electromagnetic switch has to be used, and the control device cannot be reduced in size and price.
[0007]
In addition, since an inrush current flows through the contact of the electromagnetic switch as described above, there is a problem with the contact life and reliability.
[0008]
SUMMARY OF THE INVENTION The present invention solves the above problems, and provides an electric motor control device that can reduce the size and improve the reliability of an electromagnetic switch of a power supply unit that drives a plurality of electric motors, and can realize downsizing and cost reduction. Objective.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a motor control apparatus in which a plurality of drive units are connected to a common power supply unit. The power supply unit receives an AC power supply and rectifies it into a DC voltage, and the diode bridge. An inrush current suppression resistor connected between the electrolytic capacitor for smoothing the output voltage of the power supply and suppressing an inrush current at power-on, an electromagnetic switch connected in parallel with the inrush current suppression resistor, and after rectification and smoothing A main circuit voltage comparison circuit for detecting that the main circuit voltage is equal to or higher than a predetermined voltage, an electromagnetic switch drive circuit for opening / closing a contact of the electromagnetic switch, and a plurality of servo ON signals input from the plurality of drive units and a Wired OR circuit, wherein the plurality of drive units is regulated by number of installed wired OR circuit, the main circuit voltage after rectifying and smoothing Is connected as a source to drive a plurality of motors, an electromagnetic switch in the electromagnetic switch driving circuit when the main circuit voltage is at least one of said wired OR circuit in the case of more than the predetermined voltage received a servo ON signal from the drive unit This closes the contact.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In order to solve the above-described problems, the present invention provides a motor control apparatus in which a plurality of drive units are connected to a common power supply unit. The power supply unit receives an AC power supply and rectifies it into a DC voltage, and the diode bridge. An inrush current suppression resistor connected between the electrolytic capacitor for smoothing the output voltage of the power supply and suppressing an inrush current at power-on, an electromagnetic switch connected in parallel with the inrush current suppression resistor, and after rectification and smoothing A main circuit voltage comparison circuit for detecting that the main circuit voltage is equal to or higher than a predetermined voltage, an electromagnetic switch drive circuit for opening / closing a contact of the electromagnetic switch, and a plurality of servo ON signals input from the plurality of drive units and a Wired OR circuit, wherein the plurality of drive units is regulated by number of installed wired OR circuit, the main circuit voltage after rectifying and smoothing Is connected as a source to drive a plurality of motors, an electromagnetic switch in the electromagnetic switch driving circuit when the main circuit voltage is at least one of said wired OR circuit in the case of more than the predetermined voltage received a servo ON signal from the drive unit It is an electric motor control device characterized by closing a contact.
[0011]
Further, a plurality of electric motors total driving current collector motivation controller set at equal to or less than the rated current of the electromagnetic switch contacts the connecting.
[0012]
Thus, the electromagnetic switch driving circuit, the main circuit voltage comparator circuit after detecting the above predetermined voltage, closes the at least one contact of the electromagnetic switch from receiving a servo ON signal from the drive unit of the wired OR circuit Therefore, the electrolytic capacitor is sufficiently charged, and inrush current due to insufficient charging of the electrolytic capacitor does not flow to the electromagnetic switch.
[0013]
In addition, the total number of connected motors is regulated by the number of wired OR circuits installed. If the drive current value is set equal to or lower than the rated current value of the electromagnetic switch contact, the reliability of the electromagnetic switch contact can be secured. .
[0014]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0015]
In FIG. 1, a power supply unit 11 of an electric motor control device receives an AC power supply 12 and rectifies it into a DC voltage, an electrolytic capacitor 14 that smoothes the rectified voltage, and suppresses an inrush current when the power is turned on. An inrush current suppression resistor 15, an electromagnetic switch 16 connected in parallel with the inrush current suppression resistor 15, a main circuit voltage comparison circuit 17 that detects that the main circuit voltage is equal to or higher than a predetermined voltage, and an electromagnetic switch An electromagnetic switch drive circuit 18 that opens and closes the contacts of the device 16, and a wired OR circuit 19 that receives a servo ON signal from each drive unit that drives a plurality of electric motors. The main circuit voltage comparison circuit 17 closes the contact of the electromagnetic switch 16 in response to a servo ON signal from at least one drive unit when the main circuit voltage is equal to or higher than a predetermined voltage. Further, the power supply unit 11 of the motor control device supplies the main circuit voltage to each drive unit that drives the plurality of motors.
[0016]
The operation of the above configuration will be described. When the AC power supply 12 is turned on, an inrush current for charging the electrolytic capacitor 14 flows through the inrush current suppression resistor 15. When the servo ON signal from at least one drive unit is received after the electrolytic capacitor has been charged, the wired OR circuit 19 drives the electromagnetic switch drive circuit 18 and closes the contacts of the electromagnetic switch 16. Thereby, the current supplied to the motors can be passed through the contacts of the electromagnetic switch 16 when the plurality of motors are driven.
[0017]
Thus, since the inrush current due to insufficient charging of the electrolytic capacitor does not flow to the contacts of the electromagnetic switch, the current capacity of the contacts of the electromagnetic switch can be reduced even if a plurality of electric motors are driven.
[0018]
In addition, the maximum number of motors to be connected is determined by the number of wired OR circuits installed, and the total value of the drive current of the motor can be assumed in advance. If it is set to the same or lower, it is possible to use a small and optimal electromagnetic switch, so it is possible to cope with lower prices. At the same time, the reliability of the electromagnetic switch contacts can be secured.
[0019]
【The invention's effect】
As is clear from the above embodiment, according to the present invention, after the main circuit voltage comparison circuit detects a predetermined voltage or more, at least one of the wired OR circuits receives the servo ON signal from the driver unit and then the electromagnetic switch Since the contact is closed, the current capacity of the contact of the electromagnetic switch can be reduced and the size can be reduced.
[0020]
In addition, since the maximum number of motors to be connected is determined by the number of wired OR circuits installed,
The total value of the drive current can also be assumed in advance. Furthermore, if the total value of the drive current of the motor is set to be equal to or less than the rated current value of the electromagnetic switch contact, a small and optimum electromagnetic switch can be obtained, and at the same time, the reliability of the electromagnetic switch contact can be ensured.
[0021]
Therefore, it is possible to obtain an electric motor control device that can reduce the size and improve the reliability of the electromagnetic switch of the power supply unit that drives the plurality of electric motors, and can realize downsizing and cost reduction.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a motor control device showing an embodiment of the present invention. FIG. 2 is a circuit diagram of a conventional motor control device.
DESCRIPTION OF SYMBOLS 12 AC power supply 13 Diode bridge 14 Electrolytic capacitor 15 Inrush current suppression resistor 16 Electromagnetic switch 17 Main circuit voltage comparison circuit 18 Electromagnetic switch drive circuit 19 Wired OR circuit

Claims (1)

In the motor control apparatus in which a plurality of drive units are connected to a common power supply unit, the power supply unit is provided between a diode bridge that inputs AC power and rectifies the DC voltage and an electrolytic capacitor that smoothes the output voltage of the diode bridge. An inrush current suppressing resistor that suppresses an inrush current when the power is turned on, an electromagnetic switch connected in parallel with the inrush current suppressing resistor, and a main circuit voltage after rectification smoothing is equal to or higher than a predetermined voltage. A plurality of drive units, comprising: a main circuit voltage comparison circuit to detect; an electromagnetic switch drive circuit that opens and closes contacts of the electromagnetic switch; and a plurality of wired OR circuits that input servo ON signals from the plurality of drive units. is regulated by number of installed wired OR circuit, connected to the main circuit voltage after rectifying and smoothing a power source driving a plurality of motors Motor, and at least one of said wired OR circuit when the main circuit voltage is higher than the predetermined voltage is, wherein said closing the contacts of the electromagnetic switch with electromagnetic switch drive circuit when receiving the servo ON signal from the drive unit Control device.

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