JP2007252126A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a motor controller performing regenerative braking which is not shocking sudden braking while shortening the time elapsing before complete stoppage. <P>SOLUTION: The motor controller performing regenerative braking of a motor 1 upon occurrence of obstacle in the drive power supply 2 of the motor 1 such as a DC motor or an AC motor comprises a section 5 for detecting occurrence of such an obstacle as a drive voltage cannot be applied from the drive power supply 2 to the motor 1, a switch circuit 3 consisting of a transistor which turns on when an obstacle is detected at the obstacle detecting section 5, and a constant current circuit 4 which is connected in parallel with the motor 1 when the switch circuit 3 is turned on and applying the regeneration voltage of the motor 1 such that a predetermined constant current flows. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor control device that performs a safe and quick stop of a motor when a failure occurs in a motor drive power supply device.

  There are various types of motors such as direct current motors, alternating current single phase motors, alternating current three phase motors, linear motors, etc., and drive power supply devices corresponding to these types and for purposes such as rotational speed control are used. Yes. For example, for a direct current motor, a drive power supply device having an inverter configuration that controls the rotational speed by controlling the output voltage is used. In addition, for AC single-phase motors and AC three-phase motors, a drive power supply device having an inverter configuration that controls the rotation speed by controlling the output frequency is used. For a linear motor, for example, a plurality of stator coils arranged on a straight line are sequentially switched in the direction of movement from the current position detected by the position detector and excited, and a mover made of a permanent magnet. It has the structure which moves.

  In addition, a configuration using a brake when stopping the motor is common, but a regenerative braking means that effectively uses rotational energy is also known, and a configuration that returns the regenerative power at the time of stopping to the power source side, resistance, etc. A configuration to be consumed is known. For example, as shown in FIG. 5A, a series circuit of a switch circuit 103 and a resistor 104 is connected between terminals to which a drive voltage is applied from the drive power supply device 102 of the motor (M) 101, and the motor 101 is connected. When stopping, the supply voltage from the drive power supply device 102 is turned off and the switch circuit 103 is turned on. As a result, the resistor 104 is connected between the terminals of the motor 101, the voltage generated between the terminals due to the rotation of the rotor of the motor 101 is applied to the resistor 104, and the electric power generated by the rotational energy of the rotor is resisted. It is consumed by 104 and brakes. That is, power braking or regenerative braking can be performed. In this case, when the resistance value of the resistor 104 is set to zero, the motor 101 stops rapidly, and when the resistance value of the resistor 104 is increased, the time until the complete stop is increased. That is, as shown in FIG. 5B, the rotation speed is plotted on the vertical axis, the time is plotted on the horizontal axis, and the voltage supplied to the motor 101 from the drive power supply device 102 is turned off at the timing t. When it is turned on, when the resistance value of the resistor 104 is zero, the deceleration characteristic shown by the curve a is obtained and a rapid stop is performed. In this case, it is also known to be configured to stop within one rotation. Further, when the resistance value is increased, the deceleration characteristic shown by the curve b is obtained and the vehicle gradually stops and the time until the stop is increased.

Also, by turning off the three-phase AC voltage supplied to the stator winding of the three-phase induction motor and applying a DC voltage to the stator winding, the current caused by the induced voltage of the rotor winding is rotated in a short-circuit state. Means for performing regenerative braking by flowing in the child winding is also known (see, for example, Patent Document 1). Also, the servo motor is driven by outputting a three-phase AC voltage from an inverter that inputs DC voltage. When the servo motor is stopped, the DC voltage is turned off, and the transistor in the series circuit of the resistor and transistor connected between the input terminals of the inverter is turned on. A means for performing regenerative braking is also known (see, for example, Patent Document 2). In addition, when the three-phase synchronous motor driven by the three-phase inverter is suddenly stopped, all the transistors constituting the inverter are turned off, and the regenerative voltage of the three-phase synchronous motor is set via the diodes connected in parallel with those transistors. There is also known a means for applying regenerative braking by applying regenerative power to a resistor by applying the regenerative power to the resistor by turning on the transistor, which is applied to a circuit of a resistor and a transistor connected to the input side of the inverter (for example, Patent Document 3). reference). Also, when the spindle motor stop control is performed by turning off the power, etc., the spindle motor regenerative power is supplied to the spindle motor control device to enable the control operation of the control device, and the spindle motor has a predetermined deceleration characteristic. Means for controlling the above is also known (see Patent Document 4).
Japanese Patent Application Laid-Open No. 5-344471 JP-A-6-315288 JP 2001-204184 A JP 2003-289684 A

  In general, an inverter or the like that can control a voltage or a frequency supplied to the motor is applied to the motor drive power supply device, and a normal drive voltage may not be applied to the motor due to some failure. In that case, since it becomes impossible to control the driving of the motor, it is necessary to immediately stop, for example, a precision processing table driven by the motor. Although it is conceivable to use a mechanical brake to stop the motor, there are problems such as a space for providing such a brake and generation of dust due to brake operation. Therefore, it is preferable to apply regenerative braking as described above. However, as described with reference to FIG. 5, if the resistance value of the resistor 104 is zero, rapid stop is possible. However, for example, the precision machining table is suddenly braked and placed on the precision machining table and the precision machining table. The placed workpiece may be impacted and damaged. In order to avoid such a problem, the resistance value of the resistor 104 described above is selected. However, in order to shorten the time to stop, the initial deceleration increases and the resistance value is set to zero. An approximate problem arises. Therefore, if the resistance value is selected to be large so as to reduce the initial deceleration, there is a problem that the time until complete stop becomes long.

  An object of the present invention is to solve the above-mentioned conventional problems, and to regeneratively brake a motor with a deceleration characteristic capable of shortening the time to complete stop, not shocking sudden braking. And

  The motor control device of the present invention is a motor control device that regeneratively brakes the motor when a failure occurs in the drive power supply device of the motor, and a failure detection that detects occurrence of a failure in which a drive voltage cannot be applied from the drive power supply device to the motor. And a switch circuit that is turned on when a failure is detected by the failure detection unit, and a constant current circuit that is connected in parallel with the motor when the switch circuit is turned on.

  A large constant current when the rotational speed is high based on the rotational speed detected by the rotational speed detector for detecting the rotational speed of the motor and the rotational speed detected by the rotational speed detector when the failure detection unit detects the failure of the drive power supply device. And a constant current circuit that is set to flow.

  The motor includes a mover made of a permanent magnet movably supported on a straight line, a plurality of stator coils disposed along the straight line, a position detector for detecting the position of the mover, A drive unit that sequentially selects the stator coils based on information on a current position and a movement direction of the mover by a position detector; a drive power supply device that excites the stator coils via the drive unit; and A failure detection unit that detects the occurrence of a failure in the drive power supply device, and a switch that connects a constant current circuit between power supply lines that are supplied from the drive power supply device to the drive unit when the failure detection unit detects a failure occurrence in the drive power supply device Circuit.

  When stopping a direct current motor or alternating current motor by regenerative braking, a constant current preset by a constant current circuit is flowed so that the deceleration rate when the motor is stopped is almost constant, without causing an impact and quickly. It can be stopped. In addition, by detecting the rotational speed and controlling the characteristics of the constant current circuit, the deceleration rate at the start of deceleration is lowered, and the deceleration rate is increased as the rotational speed is lowered to give an impact. In addition, the time to stop can be further reduced.

  The motor control device of the present invention will be described with reference to FIG. 1. In the motor control device that regeneratively brakes the motor 1 when a failure occurs in the drive power source device 2 of the motor 1, such as a DC motor or an AC motor, A failure detection unit 5 that detects the occurrence of a failure in which a drive voltage cannot be applied from the power supply device 2 to the motor 1, a switch circuit 3 that is turned on when a failure is detected by the failure detection unit 5, and when the switch circuit 3 is turned on, A constant current circuit 4 connected in parallel with the motor 1 is provided.

  FIG. 1 is an explanatory diagram of Embodiment 1 of the present invention. In FIG. 1A, 1 is a motor, 2 is a drive power supply device, 3 is a switch circuit composed of transistors and the like, and 4 is a constant current. A circuit 5 indicates a failure detection unit. (B) shows an example of regenerative braking characteristics. When the motor 1 is a direct current motor, the drive power supply device 2 outputs a direct current voltage to drive the motor 1, and is configured as an inverter or the like, and the rotational speed of the motor 1 is controlled by controlling the output direct current voltage. The direction of rotation of the motor 1 can be reversed by reversing the polarity of the DC voltage. In this case, although not shown, a diode is bridge-connected so that a voltage having a predetermined polarity is applied to the constant current circuit 4 even if the polarity is reversed.

  The failure detection unit 5 has a function of detecting a failure in which a drive voltage cannot be applied to the motor 1 from the drive power supply device 2 and turning on the switch circuit 3. For example, when the drive power supply device 2 is composed of an inverter, normal operation becomes impossible due to deterioration of components such as transistors, and when the drive voltage cannot be applied to the motor 1, this is detected and the switch circuit 3 is turned on. Turn on. Thereby, the regenerative voltage of the motor 1 is applied to the constant current circuit 4 via the switch circuit 3. Unlike the resistor, the constant current circuit 4 can pass a predetermined constant current even if the applied voltage changes. Therefore, the motor 1 is at time t as shown in FIG. When the switch circuit 3 is turned on, the motor stops at a constant deceleration rate corresponding to the set current of the constant current circuit 4. Therefore, it is possible to set a deceleration rate that does not give an impact. Further, even when the rotational speed is lowered, the deceleration rate can be maintained and the vehicle can be stopped quickly. As described above, the switch circuit 3 in the first embodiment can be constituted by a switching element such as a bipolar transistor or a field effect transistor, and the constant current circuit 4 detects a current to detect the transistor. A configuration to be controlled can be applied. The switch circuit 3 and the constant current circuit 4 can be configured to supply operating power from a power supply device (not shown) different from the drive power supply device 2. When the motor is a three-phase AC motor, the switch circuit 3 and the constant current circuit 4 are connected between the three-phase windings, and the induced voltage polarity of the stator coil by the permanent magnet rotor is If it is not constant, as described above, a diode is bridge-connected, and a voltage having a predetermined polarity is applied to the constant current circuit 4 even if the polarity is reversed.

  FIG. 2 is an explanatory diagram of Embodiment 2 of the present invention. In FIG. 2A, the same reference numerals as those in FIG. 1 denote the same parts, and 6 denotes a rotational speed detector. (B) shows an example of regenerative braking characteristics. The occurrence of a failure in the drive power supply device 2 is detected by the failure detection unit 5, the detection signal is input to the switch circuit 3 and turned on, and the detection signal is input to the constant current circuit 4. A detection signal from a rotation speed detector 6 that detects the rotation speed of the motor 1 is input to the constant current circuit 4. Note that the rotational speed detection signal may be input to a control unit (not shown) of the drive power supply device 2 to control the rotational speed of the motor 1.

  The constant current circuit 4 includes means for setting a constant current characteristic based on the rotation speed detection signal at the time when the failure detection signal is input. When the rotation speed is high, the current value is increased so that the rotation speed is If it is low, the current value is set small, the switch circuit 3 is turned on, and the current that flows when the regenerative power of the motor 1 is supplied to the constant current circuit 4 is switched according to the rotational speed of the motor 1. Therefore, as shown in FIG. 2B, when the rotational speed is high, the characteristics of a1 are set, and when the rotational speed is low, the characteristics of a2 are set. The time from the timing t to the stop of the motor 1 can be made substantially the same. Also in the second embodiment, the switch circuit 2 and the constant current circuit 4 are configured to supply operating power from a power supply device (not shown) different from the drive power supply device 2.

  FIG. 3 shows an example of the switch circuit 3 and the constant current circuit 4 described above. 10 is a control circuit, 11 is a rotation speed holding unit, 12 is an operational amplifier, Q1 and Q2 are transistors, and R1 and R2 are resistors. , T1 to T5 indicate terminals. Terminals T1 and T2 are terminals connected between motor terminals, terminals T3 and T4 are terminals for inputting a failure detection signal from the failure detection unit 5 (see FIG. 1 or 2), and T5 is a rotational speed detection. This is a terminal for inputting a rotational speed detection signal from the device 6 (see FIG. 2).

  The control circuit 10 inputs a reference voltage for determining the value of the current flowing through the constant current circuit 3 to the operational amplifier 12, and sets this reference voltage corresponding to the rotation speed detection signal held in the rotation speed holding unit 11. To do. For example, the reference voltage is set high when the rotation speed is high, and the reference voltage is set low when the rotation speed is low. When the failure detection signal is input to the terminals T3 and T4, the transistor Q1 of the switch circuit 3 is turned on, and the rotation speed detection signal input to the terminal T5 is held in the rotation speed holding unit 11. The control circuit 10 inputs a reference voltage corresponding to the rotation speed detection signal held in the rotation speed holding unit 11 to the operational amplifier 12. Since the regenerative power of the motor is applied to the terminals T1 and T2, a current flows through the transistors Q1 and Q2 and the resistor R1. The resistor R1 is used for current detection, and a voltage Vr corresponding to the current is input to the operational amplifier 12 via the resistor R2, and the transistor Q2 is controlled by comparing with the reference voltage from the control circuit 10 and corresponds to the reference voltage. To control the current. That is, constant current control can be performed. In this case, since the constant current characteristic corresponding to the rotation speed can be obtained, the characteristic similar to the characteristic described with reference to FIG.

  FIG. 4 is an explanatory diagram of Embodiment 3 of the present invention, showing a case where it is applied to a linear motor, 21 is a moving element having a permanent magnet, 22 is a stator having a plurality of coils, and 23 is for each coil. , A drive detector unit, 24 a position detector, 25 a drive power supply device, 26 a fault detection unit, 27 a regenerative braking unit, 28 a switch circuit, 29 a constant current circuit, and 30 a drive control unit. A DC voltage is supplied from the drive power supply device 25 to the drive switch unit 23 via the power supply line, the position of the moving element 21 is detected by the position detector 24, and drive control is performed based on the detected position information and drive direction information. The unit 30 controls the drive switch unit 23, turns on the switch constituting the drive switch unit 23, and applies a DC voltage supplied from the drive power supply device 25 through the power supply line to the coil constituting the stator 22. Then, the mover 21 is moved. Such a configuration can be applied to various known linear motor driving means.

  When the failure detection unit 26 detects the occurrence of a failure in the drive power supply device 25, the switch circuit 28 is turned on and connected to a power supply line that supplies a DC voltage from the drive power supply device 25 to the drive switch unit 23. As a result, the constant current circuit 29 is connected to both ends of the coil of the stator 22 connected via the switch in the ON state of the drive switch unit 23, and the stator generated by the permanent magnet during movement of the mover 21 is obtained. It is possible to apply the induced voltage of the coil 22 and pass a preset constant current by the constant current circuit 29 to stop the moving element 21 by regenerative braking. In this case, since the on / off of the drive switch unit 21 is controlled corresponding to the position of the moving element 21 by the position detector 24 and the moving direction of the moving element 21, until the moving element 21 stops, On / off control of the switch is continued sequentially along the moving direction. Also in the third embodiment, since regenerative braking is performed with a constant current, it can be quickly stopped without giving an impact to the moving element and the precision components moved by the moving element.

It is explanatory drawing of Example 1 of this invention. It is explanatory drawing of Example 2 of this invention. It is explanatory drawing of a constant current circuit and a switch circuit. It is explanatory drawing of Example 3 of this invention. It is explanatory drawing of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2 Drive power supply device 3 Switch circuit 4 Constant current circuit 5 Fault detection part 6 Rotation speed detector

Claims (3)

In a motor control device that regeneratively brakes the motor when a failure occurs in a motor power supply device,
A failure detection unit that detects occurrence of a failure in which a drive voltage cannot be applied to the motor from the drive power supply device;
A switch circuit that is turned on when a failure is detected by the failure detection unit;
And a constant current circuit connected in parallel with the motor when the switch circuit is turned on.   A large constant current is detected when the rotational speed is high based on the rotational speed detected by the rotational speed detector that detects the rotational speed of the motor and the rotational speed detected by the rotational speed detector when the failure detection unit detects the failure of the drive power supply device. The motor control device according to claim 1, further comprising a constant current circuit configured to flow.   The motor includes a mover made of a permanent magnet supported so as to be movable on a straight line, a plurality of stator coils arranged along the straight line, a position detector for detecting the position of the mover, and the position A drive unit that sequentially selects the stator coil based on information on a current position and a moving direction of the mover by a detector; a drive power supply device that excites the stator coil through the drive unit; and the drive A failure detection unit that detects the occurrence of a failure in the power supply device, and a switch circuit that connects a constant current circuit between power supply lines that are supplied from the drive power supply device to the drive unit when the failure detection unit detects a failure occurrence in the drive power supply device The motor control device according to claim 1, further comprising:

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