JPS5999980A - Stopping position deciding controller by induction motor - Google Patents

Abstract

PURPOSE:To rigidly hold the stop of a movable unit at the prescribed position by generating a reverse torque in a motor when the unit passes the prescribed position, returning the unit to the original, and generating a motor torque against an external force when the external force is operated on the unit. CONSTITUTION:A cycloconverter 2 controls by the voltage of a pulse width an AC frequency supplied through a 3-phase transformer 21 from a 3-phase AC power source by the duty cycle of a control pulse signal from a controller 6 contained in a microcomputer and inputs it to a 3-phase induction motor 3 connected to terminals U-W. The output frequency of the cycloconverter 2 varies positively or negatively by the value of the frequency of the control pulse signal varying by the detected position output of a movable unit from a position detector to vary the rotating direction. When an external force is applied to the unit in the negative direction after the prescribed stop, the output frequency and the output voltage of the cycloconverter 2 rise by the detected ultrafine variation signal of the position detector, and the unit is returned to the original position by the torque of the induction motor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stop positioning control device, and more particularly:
The present invention relates to a device for stopping a moving body, which is displaced by a multiphase induction motor, within a predetermined width around a predetermined position by controlling the frequency and polarity of power supplied to the induction motor.

When a movable body that is displaced by an electric motor is stopped at a predetermined position, a position detection means is provided to detect the amount of displacement of the movable body from the predetermined position, and the rotational speed of the electric motor is controlled by the blade signal. The speed of the moving object is reduced according to the degree of approach to a predetermined position, and when the moving object reaches a predetermined point slightly before the predetermined stop position, the power to the motor is cut off, and after that, inertia is used. The conventional method was to make the moving body reach a predetermined position and stop there. In this case, the distance traveled by inertia is
This is determined by the frictional force generated in each part of the moving body and the speed of the moving body when power is cut off to the motor, but no matter how accurately the speed at the time of power cutoff is controlled, the frictional force is Since the surface condition of the surface of the surface of the surface of the surface of the surface of the surface of the lubricant varies slightly depending on the amount of lubricant, the temperature, etc., it is often difficult for a moving object to reach a predetermined position or stop after passing through the predetermined position. Furthermore, if a force that causes displacement of the movable body acts on the movable body after the first stop, it is necessary to provide a brake.

In the present invention, the movable body does not stop before the predetermined position, and when it passes the predetermined position, a reverse torque is immediately generated in the electric motor to return the movable body to its original position. ′
]), even after stopping, if an external force that tries to displace the moving object acts on the moving object, the electric motor immediately generates a torque to counter it, and the moving object can be firmly stopped near a predetermined position. Therefore, B1. - Requires key 1.
Its purpose is to provide 1V for a positioning control device that does not require a stop.

In order to achieve the objective -1-, the present invention (? +I-
: The positioning control device 51 has a function of controlling the frequency, voltage, and polarity of the multiphase induction motor power supply according to the output signal of the position detection means of the moving body.

Embodiments of the present invention will be described below based on the drawings. 1st
The figure is a block diagram showing the configuration of an embodiment of the present invention, in which, for example, power is supplied from a commercial lower phase AC power source 1 to a three-phase induction motor 3 through a ZIKEN hearter 2. The moving body 4 is driven by a three-phase induction motor 3, and its position, that is,
Displacement from a predetermined point is measured by a position detector 5 using a pulse generator.
It is detected by The device detector 5 sends information regarding the position of the moving body 4 to the control unit 6 using position detection signals 14 and 17 consisting of pulse signals, and this control unit 6, which includes a microcombi 1-1, responds to the position detection signal. Control pulse signal
” into Cyclo:1 Inharter2. Zaik 11
The inverter 2 controls the frequency of the five sets of AC power sources 1 and one electric power source according to the degree of approach of the moving body 40 to a predetermined position, and controls the rotational speed of the induction motor 3 using this control pulse signal.

In this case, IJIKU! The control pulse signal input to the controller 2 is determined by the cycle of the control pulse signal input to the controller 2.
By controlling the frequency of the AC supplied from the ■phase AC power supply 1 and the voltage according to the pulse width, the τ knee-phase induction motor 3
Enter. Output frequency f of cycloconverter 2 (
i is the frequency f of the phase AC power supply 1 [the difference fd between 1 and the frequency fc (duty cycle) of the control pulse signal indicated in L]
= f (given as 3-fc. The value of this fd is
The frequency f of the control pulse signal changes depending on the output signal of the position detector 5. Depending on the value of c, it changes over positive and negative divisions, but in the case of a cycloconverter, the three-phase alternating current it outputs means the reversal of the polarity of In this way, the blade microconverter 2 has one stage that controls the frequency and voltage of the three-phase AC supplied to the induction motor 3, and one that reverses the polarity of the two-phase AC and reverses the rotation direction of the induction motor. It also has one stage.

Next Q: The microconverter 2 in this example,
An embodiment of the control section will be described.

FIG. 2 shows the circuit configuration of the control section 6 and the cycloconverter 2. The control section 6 is constituted by a microcomputer. The input interface 11 of the control unit 6 includes a position detection signal from the position detector 5 (FIG. 1) and a digital setting device 14 that specifies the stop position of the moving body 4 (FIG. 1).
The output and the input are input. The ROM stores control programs and the like. The output interface 15 is 21 [
It has 11 flip-flops FFI and FF2, and outputs the state signal of this flip-flop. This pretend
7 Buflo knobs FF and FF2 are for generating two-phase pulse signals P1 and P2, as shown in Figure 3.
Setting and resetting are repeated every cycle T, FF+ and FF2 have a phase difference of 180°, and the time from setting to reset 1- is 1 a for the logic "1". The CPU 6 has a built-in clock generator and a counter, and the program (I: FFI, J: controls the set and reset of FF2).As will be described later, the CPU 6 has a built-in clock generator and a counter. is the output frequency of the Cyclo 7 parter, and the pulse width '1
゛α determines the output voltage. ′r and 1゛α
(1~ are stored in the RAM 13. The outputs of the flip-flops FF 1 and l-' The output of the resistor of the coupler PC1 is input to the first transistor driving amplifier circuit 17, and when the resistor receives light, the 'y'-1 signal G1 reaches the ■■i level. Then, the power transistor I9 is made conductive.Similarly, the photocoupler PC2's photol transistor output is connected to the power resistor I9.
input to the transistor driving amplifier circuit 18 of
When the transistor receives light, the goo I-signal G2 becomes Hi level, making the power transistor 20 conductive.

- Input terminals j'R, S, 1' are connected to the primary winding of the three-phase transformer 21 with power and neutral point taps, and a three-phase power line of commercial communication is connected to these input terminals. The three secondary windings of the three-phase transformer 21 have one end a, b, c, and the other end d,
e, f, and each neutral point g, h, i, 7. each -6
Qa, b, c (-AL three-phase full-wave rectifier 22 is connected,
The rectified output terminals j and k are connected to the power JTI l.
The emitter and collector circuits of the resistor 19 are connected. Similarly, a three-phase full-wave rectifier 23 is also connected to each of the other ends d, e, and f of the transformer 21, and its rectified output terminals 1. The emitter and collector terminals of the power I transistor 20 are connected to rn. At 111 points g, h, and i in each of the transformer 21 (
, ”output terminal T for deriving the converted AC output,
J.V.

W is connected. A three-phase induction motor 2 is directly connected to the output terminals U, V, and W.

Next, the action will be explained.

At t3, the period '■' and pulse time width Tα of the cycloconverter control signal are written in the RAM 13 of the microcomputer, and at t3, the counter in CPtJ that counts clock pulses counts 1/2 and '''. every time, 7
1-Send command signal υ~ U7.1゛α and (T/2 +
Every time 'I'α) is counted by d), a resetting command signal is issued, and the contents of the counter are cleared to 0 every time '■' is counted by it. , L7 as in 2, and 1 according to the deviation of the comparison part.
Setting and resetting of the flip-flops FF and F2 are repeated to output a small two-phase pulse train Y)1 and P2 as shown in FIG.

In FIG. 4, the solid line indicates 71 iF string waveforms E a ,
l',', l:i.

[尤[] represents the voltage 4 appearing at each point a, b, and c of the three-phase transformer 21, and the sinusoidal waveforms Ed and Ee shown by dotted lines.

F indicates the voltage 4 appearing at each point d, e, f on the other end of the three-phase transformer 21 L2. When the signal P1 is at Hi level, the gate voltage FGH also becomes Hi level, and the power transistor 19 becomes conductive. Similarly, when the signal P2 is T(i), the data voltage G2 also becomes Hi level, and the Barry 1 transistor 20 becomes conductive.
2 when transistors 19 and 20 are both off is medium f! ,+
F, tHr 11. 'No voltage appears between each line.

When the number of transistors 19 and 2 is 4, the emitter and collector circuits of diode F and transistor 19, which constitute the full-wave rectifier 22, provide a, b,
c A circuit is formed between each point, and the output is connected to the terminal [1, V, W?
j voltage is applied and the AC motor is energized. Similar i
, :, When the second Barry l and transistor 20 becomes OFF at +-, it constitutes a full-wave rectification a23 l))? 'Image and transistor 1 and 0, 11 days, - ■ nol
-'Circuit & V, two cl, e, f (7) times between each point! M
)] When the key is pressed, a voltage is applied between the output terminals IJ, V, and W, and the voltage is changed to '/At, electric! 11 turn) 夷, h qui S, i force igre 6° 4th [RI (, iZ, IT:, string waveform]a, 卜1b, Rc.

Vertical stripes seen by Ed, Fie, and Ef-S”f It,
When the power transistor 19 is in the 4-way state, the output section) is completed.
.

■, the voltage that appears at W, and the voltage that appears at the output terminal, -4LJ, V, and W when the power transistor 20 is in a conductive state. I'm posting it. It is clear from the figure.) to 1
, the pattern of the second vertical striped portion 5) is periodic 1. i' - changes, and the lowest frequency component that is affected by the change is a sine wave with a period of 0.1 seconds. Now, the time scale t in Figure 4
This is not shown. ■, Pa)! 3, the control signal P and the period ′■゛ of 1>2 are 1, /6011t> (X Honkawa wave number f
c = 60T(2), commercial sentence Mf frequency is 50H,
In the case of output section 1. −． p-[1,V, obtained in W'
W4 constituent of rl voltage! , u, Pv,
IE 1+7 frequency 1, maf (] -1f口■n;
Become a servant.

This invention! ,, -# Er:, -11k LT, control signal P+, frequency of Pr -fC (6-dashi fc-1/T
), the frequency of the AC input applied to the primary side ζ 1
The frequency of the alternating and rare output appearing in :fd,,! , : If the relationship is f d −f i)−f c holds true.

Therefore, by changing the frequency of the control signal, the output frequency fd can be arbitrarily and continuously changed, and the rotational speed of the three-phase AC motor can be arbitrarily and continuously controlled while maintaining the required torque. I can do it. Furthermore, by changing the pulse width Tα of the control signals PI and P2, the alternating current voltage output at the frequency fd can be effectively changed, and the rotational speed of the motor can also be controlled by changing the voltage.

Further, the relationship between l·lux and rotational speed of the induction motor exhibits characteristics as shown in FIG. 5, and the rotational speed depends on the voltage and frequency of the power supply and the size of the load. That is, in the figure, the horizontal axis is the rotational speed, and the vertical axis is the torque. If the voltage and frequency are kept constant, a torque curve as shown by curve a, for example, can be obtained. When the rotational speed is equal to the periodic rotational speed No., that is, when the motor is rotating without "slip", l・lux is zero,
Generally, maximum torque is shown at 10 to 20% slip. Also, when the rotation speed exceeds NO, there is a negative torque, that is, [braking force]
occurs. Normally, an induction motor in a steady state rotates with a torque that is balanced by the reaction force of the driven body when the slip is approximately 5%. Reduce the power frequency and reduce the synchronous rotation speed to No'
If it is set to (<No), the curve a will move to the curve A, and if the voltage is increased while keeping the synchronous rotation speed at NO, the torque curve will move to the curve C.

By the way, in the configuration of the embodiment of the present invention as shown in FIG. 1, while the movable body 4 is sufficiently far away from the predetermined stop position, the induction motor 3 is supplied with three-phase AC at the rated or almost rated frequency and voltage. is being supplied, but as it approaches the predetermined position, the output frequency of the cycloconverter decreases, and therefore both the synchronous rotation speed and the actual rotation speed of the induction motor decrease, and the moving body 4 finally decreases its moving speed. reaches the predetermined position. For convenience of explanation below, the moving direction of the moving body 4 so far will be referred to as "positive -1", and the opposite direction will be referred to as "negative".
direction. Here, we will consider the general case where an external force that tries to displace the moving body 4 is acting even when the moving body 4 is in a stopped state, and the direction of the force is in the negative direction defined above. If so, the stopping of the movable body 4 at a predetermined position depends on the balance between the zero rotation torque of the induction motor 4 and the external force. That is, the output frequency Ns of the cycloconverter 2 at this time is much smaller than the initial value No, and the torque curve shown by curve a in FIG.
It has moved to the position of curve d in the figure, and the torque τS of the induction motor at zero rotation speed and the external force are in balance. After the movable body 4 has stopped at a predetermined position in this way, if an external force in the negative direction is further applied for some reason, the position detector 5 will detect the slight displacement of the movable body due to this, and The output frequency or output voltage of the cycloconverter increases in response to the signal, and the induction motor 3 generates l·rook larger than the torque τS to return the movable body 4 to its original position. The line 1 to silk of the induction motor when the moving body 4 returns to the predetermined position is represented by a curve e or f, and τS'
(τS) is balanced by the force at this time.Curve C is a 1-torque curve when the output voltage of cycloconverter 2 increases, and curve f is a torque curve when the output frequency increases. Next, when a positive I force acts on the moving body 4, the position detector 5 captures the slight displacement of the moving body due to it, and the output signal of the position detector 5 causes the output frequency of the cycloconverter 2 to become 1 negative. That is, the polarity of the output three-phase alternating current is reversed, and a reverse rotational torque τS is generated in the induction motor, which holds the moving body 4 at a predetermined position again.At this time, the I-Luke curve of the induction motor is Indicated by g.However,
In this case as well, in order to generate the same torque τS', the torque curve may be curved, and if it is curved, the "absolute value -" of the output frequency of the cycloconverter is lower than in the case of curve g. But the voltage is high. In 1-1 below, the zero rotation torque of the induction motor 3 can be controlled by changing either the output frequency or the voltage of the cycloconverter 2, or by changing both the frequency and the voltage. The method to be used can be selected as appropriate depending on the characteristics of the induction motor actually used and the load characteristics of the moving body.According to the selection, the program of the microcombination unit 1 built into the control unit 6 is programmed. Just create it differently.

As is clear from the following explanation, according to the present invention, even if there is a change in the external force that tries to displace the moving body after it has stopped, the moving body can be immediately returned to its home position by countering the change. A stop positioning control device is obtained which can be held there.

Note that the present invention can be implemented by replacing the three-phase AC power supply 1 and the cycloconverter 2 with a DC power supply and an inverter, respectively, or by replacing the three-phase AC power supply 1 and the cycloconverter 2 with a DC power supply and an inverter.
It is also possible to implement this using an image sensor, linear encoder, potentiometer, etc.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a diagram showing an example of the configuration of the cycloconverter 2 and the control section 6 shown in FIG. FIG. 3 shows a waveform diagram of the control signal output from the control section 6. As shown in FIG. FIG. 4 is an explanatory diagram of the operation of the cycloconverter 2. FIG. 5 is a torque characteristic diagram of the induction motor, and FIG. 6 is an explanatory diagram of moving body stopping action showing changes in zero rotation torque of the induction motor in an embodiment of the present invention. 1----Three-phase AC power supply 2-Cycloconverter 3-Induction motor 4-Moving body 5-Position detector 6-Control unit 11-Human power interface 12-p
oM 13-RAM 14-Digital setting device 15-Output interface 17.18--Amplifier circuit 19.20--Power transistor 21-Three-phase transformer (transformer) 22.23-Three-phase full-wave rectifier circuit Patent application Person M-System Gikenka Co., Ltd. Person Patent Attorney Nishi 1) New Ward 43 Figure 4-432-1-

Claims (1)

[Claims] A frequency converter that outputs a desired frequency and voltage, a polyphase induction motor that is driven by the output of this frequency converter, and the amount of displacement from a fixed position of a moving object that is displaced by being driven by this polyphase induction motor. a rotational direction switching means for reversing the rotational direction of the polyphase induction motor indicated by F; and a rotational direction switching means for reversing the rotational direction of the multiphase induction motor; a control section that controls the set position of the rotation direction switching means, and while the absolute value of the displacement amount detected by the displacement amount detection means is larger than a predetermined value, the absolute value of the displacement amount decreases and the frequency conversion section The rotational speed of the induction motor is decreased by decreasing the output frequency of A stop positioning control device using an induction motor, characterized in that the movable body is kept within a predetermined width centered at a predetermined position by reversing the movable body.