JPS63178779A - Controller for linear induction motor - Google Patents

Abstract

PURPOSE:To shorten the regulating time of positioning, by detecting the length of a section confronted with the stator of a secondary conductor plate, and by controlling the output of a power-supply device according to said length. CONSTITUTION:A car body 1 carried along a carrying route is supported in a state that it is levitated by a magnetic force under guide-rails 2. Accordingly, on the lower surface section of the guide-rails 2, a ferromagnetic substance plate 3 is fitted, and on the upper surface of the car body 1, electromagnets 4a, 4b supporting magnetically with a magnetic attracting force are mounted. Besides, under the guide-rails 2 and at a static position, a stator 11 formed with an effective length ls in the moving direction of the car body 1 is set, and the secondary conductor plate 13 of a length lr composing the stator 11 and a linear induction motor 12 is fixed. The yoke 14 of the stator 11 is provided with a reflection type optical-sensor 20, and its output signal is induced to a controller 21 and is fed to a stator winding 15 via a power-supply device 22, to be controlled. Then, in correlation between the stator 11 and the secondary conductor plate 13, a thrust and a braking force are controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Field of Industrial Application) The present invention relates to a control device for controlling the stop and acceleration/deceleration of a linear induction motor configured in a so-called short-layer quadratic type.

(Prior Art) As is well known, linear induction motors are not only capable of non-contact driving but also have excellent acceleration/deceleration characteristics. For this reason, it has been used as a power source for passenger transportation systems, goods transportation systems in factories, etc. Many such systems.

The stator, which is the primary side of the linear induction motor, was attached to the movable body, and a secondary conductor plate was provided along the entire length of the moving path of the two-part movable body. So-called short molding is used, or a finite length secondary conductor plate is attached to the moving body side, and a stator is provided along the entire length of the moving path. It adopts a so-called short two molding configuration.

Therefore, in a device employing the above configuration, the stator and the secondary conductor plate are always facing each other, so it is possible to stop and start at any location on the moving path, and the stator windings are constant. Uniform thrust and braking force can be obtained by supplying electric power to the

In contrast, recently, for goods transport systems within buildings, secondary conductor/body plates are installed on the moving object side, that is, on the vehicle side, and stators are distributed at key points along the transport route of this vehicle. A system has been developed in which thrust or braking force is applied to the vehicle when the vehicle passes through the stator sections, and the vehicle is caused to coast when moving between the stator sections. By employing the inter-stator coasting system in this way, not only can the conveyance path constituent members be made lighter and less expensive, but also the capacity of the motor excitation power source can be significantly reduced. The following method is adopted as a means for actually controlling the system configured as described above, that is, the linear induction motor. In other words, taking stop control, which is the most difficult type of control, as an example, when trying to stop a vehicle at a predetermined position, the position of the vehicle relative to this stop position is detected, and based on this detection result, the stator winding is adjusted. Control is performed by controlling the flowing current and phase sequence, or in addition to this control, detecting the speed of the vehicle and feeding back this detection result to the current control of the stator winding.

However, such a control method has the following problems. In other words, in a linear induction motor with a so-called short-layer quadratic configuration in which the stator and secondary conductor plates have only a certain length as described above, the secondary conductor plates absorb the moving magnetic field on the stator surface. When entering the generation area, the length of the portion of the secondary conductor plate that receives thrust and braking force changes moment by moment. Conventional control systems do not take into account at all the changes in thrust and braking force caused by changes in the length of the portion of the secondary conductor plate facing the stator. For this reason.

There have been problems in that it takes a long time to position and settle the vehicle at a predetermined stopping position, and that excessive acceleration and deceleration forces act on the vehicle.

(Problems to be Solved by the Invention) As described above, in the conventional control device for controlling a linear induction motor having a short-layer quadratic configuration.

There has been a problem in that stop control and acceleration/deceleration control cannot be performed satisfactorily due to changes in thrust and braking force caused by changes in the length of the portion of the secondary conductor plate facing the stator.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a control device for a linear induction motor that can perform stop control and acceleration/deceleration control favorably without impairing the characteristics of the short-layer quadratic structure.

[Structure of the Invention] (Means for Solving the Problem) The present invention provides a linear motor including a stator and a secondary conductor plate that are arranged to be relatively movable and whose length in the moving direction is shorter than the movable distance. In a control device that controls the stopping and acceleration/deceleration of an induction motor.

The secondary conductor plate includes a power supply device that energizes a multiphase winding wound around the stator, and a means for detecting at least a length of a portion of the secondary conductor plate that faces the stator. relative relationship detection means for detecting the relative relationship between and the stator;
A power supply control system is provided that controls the output of the power supply device based on the output signal obtained by this means.

(Function) As described above, in a linear induction motor having a short-layer quadratic configuration, the length of the portion of the secondary conductor plate receiving thrust and braking force changes from moment to moment. In the present invention, the opposing portions of the stator and the secondary conductor plate.

That is, the length of the portion that generates thrust and braking force is detected by the relative relationship detection means, and the output of the power supply device is controlled so that thrust and braking force commensurate with the detected length are applied. Therefore, it is possible to smoothly accelerate and decelerate to a predetermined speed, and also to smoothly stop the vehicle at a predetermined stop position.

(Example) Examples will be described below with reference to two drawings.

FIG. 1 shows a local diagram of an example in which a linear induction motor having a short-layer quadratic configuration controlled by a control device according to an embodiment of the present invention is incorporated into a system for circulating articles in one direction. FIG.

In the figure, reference numeral 1 denotes a vehicle that conveys articles along a predetermined conveyance route in the direction indicated by a large arrow P in the figure. This vehicle 1 is supported in a suspended state by magnetic force below a guide rail 2 provided along a conveyance route. That is, a ferromagnetic plate 3 is attached to the lower surface of the guide rail 2.

Further, at a position facing the ferromagnetic plate 3 on the upper surface of the vehicle 1, there is an electromagnet 4a that magnetically supports the vehicle 1 in a completely non-contact manner by the magnetic attraction force generated between the ferromagnetic plate 3 and the ferromagnetic plate 3.

4b is installed. Note that the vehicle 1 includes an electromagnet 4a,
4b, a control circuit for controlling the excitation current, and a gap sensor 5 that detects the gap length between the vehicle 1 and the ferromagnetic plate 3. The excitation current of each electromagnet 4a, 4b is controlled so that the gap length always remains at a predetermined value.

A stator 11 having an effective length of S in the moving direction of the vehicle 1 is disposed below the guide rail 2 and at a stationary position. A secondary conductor plate 13 having a length J2r (in this example, set to i?s>, &r) constituting a short-layer quadratic linear induction motor 12 is fixed. The stator 11 includes a yoke 14 made of a plurality of laminated comb-shaped thin ferromagnetic plates each having a plurality of grooves, and a stator winding 15 wound in a multiphase manner around the grooves of the yoke 14. It is made up of. On the other hand, the secondary conductor plate 13 is made of a copper plate, an aluminum plate, or the like.

On the lower surface of the secondary conductor plate 13, as shown in FIG. 2, a striped pattern 18 in which dark areas 16 and bright areas 17 with different reflectances are arranged at a constant pitch is pasted or coated so as to move in the direction of movement of the vehicle 1. The vehicle 1 is formed on the upper surface of the yoke 14.
A reflective optical sensor 20 is provided in the hole 19 formed at the end on the side where the stripes enter, and outputs a pulse-like signal in response to the striped pattern 18. The output signal of the optical sensor 20 is introduced into the control device 21, and the stator winding 15 is energized by the output of the power supply device 22, which is a variable output inverter built into the control device 21. It has become.

The control device 21 receives a stop command signal Y1 given from the outside.
．． The control system is configured to automatically switch according to the start command signal "2 + acceleration command signal Y3. deceleration command signal Y4. For example, in the stop control mode, a control system as shown in Fig. 3 is formed. In other words, when the stop command signal Y1 is given, the adder 23
A stop position signal XO is applied to one input end of the .

This stop position signal XO is transmitted to the stator 11 of the secondary conductor plate 13.
The length of the part facing , f? This corresponds to a.

On the other hand, the position signal X obtained by the position detector 24 is introduced into the other input terminal of the adder 23.

The position detector 24 counts the output pulses of the optical sensor 20 described above and outputs a position signal X corresponding to the actual Ia. Adder 23 outputs the deviation between the two signals. This deviation signal is introduced into the target speed calculation section 25. The target speed calculation unit 25 calculates a target speed VQ that allows smooth deceleration with a constant deceleration, for example, according to the distance between the stop position designated by the stop position signal XO and the current position. This speed signal VO is introduced into one input of adder 26. The other input terminal of the adder 26 receives the actual speed signal V of the vehicle 1 detected by the speed detector 27.
will be introduced. Note that the speed detector 27 detects the actual speed of the vehicle 1 from the output pulse interval of the optical sensor 20 described above. The adder 26 outputs the deviation between both speed signals, and this deviation signal is introduced into the voltage calculation section 28. The voltage calculation section 28 receives the speed deviation signal and the position signal X at the calculation section 29.
ia calculated based on and the effective length S of the stator 11
The power supply voltage command value e of the power supply device 22 is calculated by introducing the ratio K between the two.

Here, the functions of the voltage calculating section 28 and the calculating section 29 will be explained as follows. That is, the thrust or braking force F1 generated by the induction motor is generally given by the following equation.

Fl-(C6E2)/(F2+52x2)...(1) In equation (1), F2. x2 is the resistance and reactance of the secondary side, S is the slip, E is the applied voltage,
C is a constant. On the other hand, the generated thrust or braking force F2 of the short-order short-double linear induction motor 12, which is the object of this embodiment, is determined by the length ia of the portion where the stator 11 and the secondary conductor plate 13 face each other. Effective length of stator 11, ffs
When K is the ratio of

F2- (KCsE2)/ (F2+52x2)...
(2) Therefore, if the thrust or braking force to be applied to the secondary conductor plate 13 is F3, the voltage E3 to be applied to the stator winding 15 of the linear induction motor 12 is given by the following equation.

(3) The voltage calculation unit 28 calculates the output voltage command value e of the power supply device 22 based on the above equation (3). In addition.

In equation (3), when the ratio K is zero, that is, the secondary conductor plate 1
3 is not facing the stator 11, the output voltage command value e becomes infinite, causing a problem. For this reason, a calculation unit 29 is provided, and the calculation unit 29 calculates K in correspondence with the position X of the secondary conductor plate 13 with respect to the stator 11 as follows.

FIG. 4 illustrates the above relationship. Also.

Figure 5 is l! Position signals X and K when set to r > S
It shows the relationship between

The above explanation is about the stop control system, but the start command signal Y2+acceleration command signal Y3. When the deceleration command signal Y4 is introduced, the adder 2 is activated by the switches 30 and 31.
3 and the target speed calculation unit 25 are separated, and the corresponding speed signals V1. A control system giving v2°■3 is formed. Start command signal Y2. When the acceleration command signal Y3 is given, the output of the power supply device 22 is applied to the stator winding 15 in a phase order that can give a thrust to the secondary conductor plate 13, and at other times, it is applied in a phase order that can give a braking force. Ru.

Note that Fd in FIG. 3 indicates running resistance.

With such a configuration, when the stop command signal Y1 is given from the outside while the vehicle 1 is moving.

A stop position signal Xo is applied to one input terminal of the adder 23. At this time, when the vehicle 1 is traveling in front of the position where the stator 11 is provided, that is, in front of the position where the secondary conductor plate 13 faces the stator 11, the position detector 24 and the speed detector The output of 27 maintains a zero state. Therefore, the speed signal introduced into the voltage calculation section 28 becomes the maximum, and the value of the ratio output from the calculation section 29 becomes the minimum value α. Therefore, the voltage calculation section 28
The power supply voltage command value e outputted from the motor also becomes the maximum value, and as a result, the stator winding 15 becomes excited with the maximum voltage value. Note that the phase sequence in this excitation is the secondary conductor plate 13
This is a phase sequence that allows braking force to be applied to.

When the vehicle 1 approaches the stator 11 and the tip of the secondary conductor plate 13 enters the effective length Js of the stator 11.

Since a braking force acts on this tip, the vehicle 1 starts decelerating. In this way, when a part of the tip 15 of the secondary conductor plate 13 enters the effective length S of the stator 11, the optical sensor 2
Since the output pulse is sent from 0, the position detector 24 sends out a position signal X corresponding to No. 0, and the speed detector 27 sends out a speed signal V corresponding to the actual speed of the vehicle 1. Ru. Therefore, the speed signal vo output from the target speed calculation section 25 gradually decreases, and a deviation signal between the speed signal VQ and the speed signal V is introduced into the voltage calculation section 28. Therefore, the power supply voltage command value e sent from the voltage calculation section 28 also gradually decreases.

During this period, the secondary conductor plate 13. In other words, a braking force is applied to the vehicle 1, so that the vehicle 1 is decelerated. When the vehicle 1 further advances and the length fa of the portion of the secondary conductor plate 13 facing the stator 11 exceeds α, the value of the ratio output from the calculation unit 29 starts to increase. Therefore, the power supply voltage command value e further decreases, and the output voltage of the power supply device 22 also decreases further.

As mentioned above, as the length a of the secondary conductor plate 13 facing the stator 11 increases, the braking force increases, and the vehicle 1
There is a possibility that the motor will stop rapidly at the =16 = position before reaching the target stop position. However, if the output voltage of the power supply device 22 is lowered by changing the ratio K based on the position signal X of the position detector 24 as in this embodiment, the vehicle 1 will not suddenly stop. Instead, the vehicle 1 will stop when it advances to the stop position specified by the stop position signal XQ. Therefore, it is possible to realize a smooth stop.

Further, as can be seen from the above explanation, when the start command signal Y2 is given, the start is started with the value of the ratio being the maximum value, and the secondary conductor plate 13 is placed opposite the stator 11. Control is performed such that the ratio K becomes smaller as the length of the portion becomes shorter. Therefore, even if the length of the portion of the secondary conductor plate 13 facing the stator 11 is shortened, a large propulsive force can be applied and a smooth start can be achieved. Similarly, when the acceleration command signal Y3 is given, a large Propulsive force can be provided, and smooth acceleration can be achieved. Further, when the deceleration command signal Y4 is given, smooth deceleration is similarly performed.

Note that the present invention is not limited to the above embodiments.

That is, the above embodiment is an example in which the present invention is applied to a system in which a vehicle, that is, a moving object moves only in one direction.
The invention is also applicable to systems moving in both directions. In this case, it is necessary to provide optical sensors at both ends that define the effective length of the stator. Also, the effective length of the stator,
If the length Jr of the secondary conductor plate is significantly shorter than &s, a plurality of optical sensors may be arranged at appropriate intervals so that two position signals can be obtained continuously. Further, in the above embodiment, a single-sided linear induction motor having only one stator and one secondary conductor plate is used, but it has two stators facing each other.

It is also possible to use a double-sided linear induction motor in which one secondary conductor moves relatively between the stators. Further, in the above embodiment, the secondary conductor plate is attached to the vehicle side and the stator is fixed at a stationary position, but the two may be attached in an inverse relationship.

Furthermore, in the above embodiments, the vehicle, that is, the moving object, is supported by magnetic force in a completely non-contact manner.

It may be supported on the guide rail by wheels or by pneumatic force. Furthermore, in the above embodiment, a striped pattern consisting of bright and dark areas is provided on the secondary conductor plate side.

Although a reflective optical sensor for detecting this striped pattern is provided on the stator side, it may be provided in the opposite relationship. Also,
The means for detecting the length of the opposing portion of the stator and the secondary conductor plate is not limited to the above embodiment.

Combination of a ladder-shaped member and a transmission type optical sensor 2 Combination of a ladder-shaped member made of ferromagnetic material and a magnetic sensor,
It is also possible to use a combination of a ladder-shaped member made of conductive material and an eddy current sensor. Also, power supplies are not limited to inverters.

It is also possible to use a commercial power source whose voltage level and phase sequence can be varied.

[Effects of the Invention] As described above, according to the present invention, the length of the portion of the secondary conductor plate facing the stator is detected, and the output of the power supply device is controlled in accordance with this length. Therefore, smooth acceleration/deceleration and stop control can be performed even in a short-layer secondary type linear induction motor where the length of the stator is approximately the same as the length of the secondary conductor plate. - It is possible to shorten the positioning settling time during stop control, which is a problem when using a short-layer quadratic configuration without impairing the characteristics of the next-layer quadratic configuration.

[Brief explanation of the drawing]

FIG. 1 is a local configuration diagram of an example in which a linear induction motor with a short-layer quadratic configuration controlled by a control device according to an embodiment of the present invention is incorporated into an article conveyance system, and FIG. FIG. 3 is a control block diagram of a control device according to an embodiment of the present invention, and FIG. 4 is a perspective view showing only the secondary conductor plate of the induction motor, and FIG. and FIG. 5 are diagrams for explaining the functions of the arithmetic unit when the conditions are changed. 1...Vehicle, 2...Guide rail, 3...Ferromagnetic plate. 4a, 4b... Electromagnet, 5... Gap sensor, 1
1... Stator, 12... Linear induction motor, 13...
... Secondary conductor plate, 15 ... Stator winding, 18 ... Striped pattern, 20 ... Optical sensor, 21 ... Control device, 22
...Power supply device. 24...Position detector, 25...Target speed calculation unit, 2
8... Voltage calculation unit, 29... Calculation unit. Applicant's agent Patent attorney Takehiko Suzue Figure 5

Claims (9)

[Claims] (1) In a control device that performs stop and acceleration/deceleration control of a linear induction motor that is provided with a stator and a secondary conductor plate that are arranged to be relatively movable and whose length in the moving direction is shorter than the movable distance, the fixed a power supply device that energizes a polyphase winding wound around the secondary conductor plate; A linear linear motor comprising: a relative relationship detection means for detecting a relative relationship with a stator; and a power supply control system that controls the output of the power supply device based on an output signal obtained by the means. Control device for induction motor. (2) The linear induction motor according to claim 1, wherein the relative relationship detection means includes means for detecting relative speed between the secondary conductor plate and the stator. control device. (3) The means for detecting the length of the portion of the secondary conductor plate facing the stator includes a striped pattern arranged on either one side of the secondary conductor plate or the stator. 2. The control device for a linear induction motor according to claim 1, further comprising a reflective optical sensor disposed on the other side to detect passage of the pattern. (4) The means for detecting the length of the portion of the secondary conductor plate facing the stator may include a ladder-like member disposed on either side of the secondary conductor plate or the stator. 2. The control device for a linear induction motor according to claim 1, further comprising: a transmission type optical sensor disposed on the other side to detect passage of the member. (5) The means for detecting the length of the portion of the secondary conductor plate facing the stator is made of a ferromagnetic material disposed on either side of the secondary conductor plate or the stator. 2. A control device for a linear induction motor according to claim 1, comprising a ladder-like member and a magnetic sensor disposed on the other side to detect passage of the member. (6) The output of the sensor is also used as an input signal for means for detecting relative speed between the secondary conductor plate and the stator. The control device for a linear induction motor according to any one of Item 5. (7) A control device for a linear induction motor according to claim 1, wherein the linear induction motor has one stator and one secondary conductor plate. . (8) The linear induction motor has two stators arranged opposite to each other and one secondary conductor plate that moves relatively between these stators. A control device for a linear induction motor according to scope 1. (9) The control device for a linear induction motor according to claim 1, wherein the power supply device is a variable output inverter.