JPS61164487A - Method of controlling linear motor - Google Patents

Abstract

PURPOSE:To obtain a uniform thrust even if a movable element of a linear motor is disposed at any position by determining the pattern of a current from the waveform of an induced voltage. CONSTITUTION:A movable element 2 has raised pole teeth 2a, 2b and recess pole teeth 3c disposed at the prescribed length P1 in the longitudinal direction. Raised stator teeth 3a-3c and recess stator teeth 3d, 3e are disposed on the stator 3, and coils 4a, 4b, 4c of a coil section 4 are wound on the teeth 3a 3c. The coils 4a-4c of the coil section 4 are connected with an inverter, and the induced voltage is input to an induced voltage discriminator. A current switching signal is input to a current ROM regarding a selective current pattern supply circuit to control the inverter on the basis thereof.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for controlling a linear motor, and in particular, a method for selecting and determining a current pattern to be applied to a linear motor to drive its mover. The present invention relates to a method of controlling a linear motor that reduces thrust pulsation and enables suitable operation.

[Background of the invention]

In a linear motor having teeth on a stator and a mover,
When thrust pulsation occurs, controllability is extremely poor in obtaining constant acceleration, speed control, and precise positioning.

However, the thrust generated by a motor is determined by the induced voltage and the pattern and phase of the current flowing through it, and although there has been no development of this current pattern etc. in the past, in linear induction motors etc. , applying the local source voltage as it is,
There are no examples that describe flow patterns, etc.

[Purpose of the invention]

The present invention provides a method for controlling a linear motor, which makes it possible to obtain a uniform thrust force no matter where the movable element of the linear motor is located, and to reduce thrust pulsations during running. Its purpose is to

[Summary of the invention]

A method for controlling a linear motor according to the present invention includes: a first magnetic pole portion having a plurality of tooth-shaped and uneven magnetic pole teeth made of a magnetic material arranged at a constant length in a longitudinal direction; The second magnetic pole part has several 4i tooth-shaped uneven magnetic pole teeth made of a magnetic material facing the first magnetic pole part with a slight air gap.
IJ = in an amotor, the ratio of the number of magnetic pole teeth formed by the convex portion in the facing portion of the first magnetic pole portion and the second magnetic pole portion is a multiple of 2 = 3; The pattern of the energizing current is determined based on the waveform of the induced voltage generated in 742 or the first magnetic pole portion based on driving the second magnetic pole portion.

Furthermore, I would like to add the following and 29.

In order to achieve the above object, the present invention focuses on the fact that the thrust generated by a linear motor is determined by the induced voltage and the magnitude and phase of the current. It is an attempt to control the decisions made.

[Embodiments of the invention]

Embodiments of the seventeenth near motor control method of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a plane parallel to the direction of movement of a linear motor used to implement a method for controlling a linear motor according to an embodiment of the present invention, and FIG. 44.5 is a front view, and FIG. 3 is a schematic configuration diagram of a control circuit used to implement the control method. FIG. Figure 6 shows the magnetic flux and induced voltage.

Figure 7 is a diagram of the induced voltage waveform generated in the three-phase coil, Figure 8 is a diagram of the thrust force generated in the three-phase coil, and Figures '49 to 11 are curve diagrams representing the induced voltage. FIG. 6 is a diagram showing each thrust curve when the phase difference is Δxi).

First, in Figures 1 and 2, 1 is the mover yoke, 2
is a mover, 2a to 2C are magnetic pole teeth, 3 is a stator, 3a to 3
e is a stator tooth, 4 is a coil part, 4a to 4C are coils, 5
1 is a cart, 6 wheels, 7 is a yoke, 8 is a magnet, and 9 is a frame.

That is, the movable element 2 includes a plurality of single-shaped convex magnetic pole teeth 2a made of a magnetic material and arranged on the movable element yoke 1 at a constant length Pl in the longitudinal direction thereof.

2b, with 2ct concave magnetic pole teeth.

Thus, convex stator teeth 3a to 3c related to a plurality of magnetic pole figures made of magnetic material on the stator 3 while maintaining a slight air vA with the magnetic poles *2a and 2b.

The concave stator teeth 3d and 3e are opposed to each other, and the length of the stator teeth 3a to 3c is Pl as shown in the figure.
It is.

In the illustrated embodiment, 2P1 is 36 in electrical angle.
It's 0 degrees.

Coils 4a, 4b, 4c of the coil section 4 are wound around the stator teeth 3a, 3b, 3c.
Between 3b and between 3b and 3c, stator teeth 3d and 3e are arranged with an interval of Ps/3 apart.

Here, the mover 2 corresponds to the first magnetic pole part,
The stator 3, which is divided into two parts, includes a coil part 4 and a magnet 8.
1 corresponds to the second magnetic pole part.

Magnets 8 are arranged at both ends of the stator teeth 3a to 3C so that the same poles face the teeth on the stator 3, and the other pole surface of the magnets 8 is placed on the yoke 7. It is something that can be installed.

The truck 5 includes a mover yoke 1 and magnetic pole teeth 2a.

2b, 2Ct- is attached, and is spatially supported between the stator 3 and the yoke 7 via wheels 6, and the contact portion is only at the wheels 6. It is. Further, the wheels 6 have rollers 9 or slide on a frame 9.

With the above configuration, the magnetic flux of the magnet 8 passes through the magnetic path shown by the broken line in FIG.

FIG. 3 shows a control circuit according to the above configuration.

That is, the coils 4a to 4C of the coil section 4 are connected to an inverter, and their induced voltages are input to an induced voltage determination circuit, and the output of the current pattern switching signal is used to determine the selective energization. The signal is inputted to the stream converter OM related to the pattern supply circuit, and outputted to the above-mentioned inverter based on the input.

Further, the above-mentioned current sensor OM is configured such that the output from the encoder section related to the position detector facing the movable element 2 is manually inputted.Next, regarding the control with the above configuration, 4 to 11, the explanation will be given including the movement l/l:.

Fig. 44 shows the case where the magnetic resistance of the magnetic circuit shown by the broken line in Fig. 2 is minimized when the magnetic pole teeth 2a and the stator @ 3a overlap, and Fig. 5 shows the case where the magnetic resistance of the magnetic circuit is minimized. This shows the case where the stator tooth 3a is located between the magnetic pole teeth 2a and 2b at the magnetic pole position where the resistance is maximum.

As described above, the magnetic pole teeth 2a arranged on the movable element yoke 1
, 2b move on the stator teeth 3a, the magnetic flux 10a changes as shown in Figure IC1!6.

Due to the change in this magnetic flux 10a, an induced voltage 11a is generated in the coil 4a.

The thrust of the motor is determined by the product of this induced voltage 11a and the current flowing through the coil 4a.

In the case of FIG. 6, the induced voltage 11a has a step-like convex shape, so the control circuit of FIG. A trapezoidal wave-shaped electric current 'R' is applied, thereby making it possible to obtain a trapezoidal wave-shaped thrust in the positive direction. In addition, if currents of opposite phases are applied, a thrust force in the opposite direction will be generated in the next case.

Reference numeral 132 in FIG. 6 shows a thrust curve generated in the former case of the same phase.

This thrust curve 13a occurs in the coil 4a shown in FIGS. 4 and 5, and is shifted by 240 degrees in electrical angle.
That is, as shown in FIG. 1, the coil 4b is arranged at a position shifted by Pr+1/3P1.

4C toy, the induced voltages 11a and llb shown in FIG.

11C occurs.

Magnetic pole teeth 2a are attached to each phase of these three induced voltages 118 to IIC.
, 2b and the stator teeth 3a to 3C and supply a trapezoidal waveform current of the same phase, a low ripple thrust curve 14t shown in FIG. 8 can be obtained.

Therefore, in this embodiment 2, as described earlier in FIG. and stator teeth 3a to 3C
The numbers of oT! were set to 2 and 3, respectively, that is, the oT! The ratio of the number of magnetic pole teeth arranged on the child yoke 1 to the number of stator teeth is 2=3. 2. This ratio can be 2:3, including the 1x ratio above.

According to this embodiment, a low-ripple thrust force can be obtained by passing an in-phase trapezoidal wave current through three-phase induced voltages having a phase difference of 2π/3, and at any location. By being able to obtain a nearly uniform thrust, there is a control effect that can be achieved by a motor with good controllability and low torque ripple.

However, the above explanation relates to a case where the waveform of the induced voltage of the motor is a step-like convex shape, and is generally
The fc explanation assumes that the current is a trapezoidal wave, but in the opposite case, if the induced voltage is a trapezoidal wave, the same effect can be obtained even if a step-shaped convex current is passed through the current. It is.

In addition, the above explanation has been made for the case where the phase difference between the induced voltage generated by the coil and the flowing HL current is zero.
When actually performing control in combination with a control circuit, it is extremely difficult to conduct current at the ideal phase difference of zero due to the delay time of the control circuit, the position shift of the position detector, etc., and the step-like induced voltage In this case, as shown in FIG.
When -1 is energized, the thrust generated by the three-phase coil drops by the width of the phase difference ΔX, as shown by thrust curve 14A, resulting in poor controllability. It's become.

In addition, FIG. 11 shows that when a step waveform induced voltage 11a is supplied with a sinusoidal current 12a-2 and a phase difference ΔX occurs, the thrust generated in the three-phase coil is expressed by the thrust curve As shown by 14B, 9, pulsations occur in the thrust in the section of the phase difference ΔX.

Further, even if a sinusoidal current with a phase difference of zero is applied to the step-waveform induced voltage, the thrust curve does not form a straight line, resulting in poor controllability.

FIG. 10 shows a case in which a trapezoidal wave current 12a is applied to the step waveform induced voltage 11a according to the present invention with a phase difference ΔX.

The thrust force in this case is shown by thrust curve 14-1, and compared to the case where a current having the same shape as the induced voltage of other waveforms or a sinusoidal current is applied, a thrust output with the least thrust pulsation can be obtained. It is something.

To summarize the above explanation, if the phase difference is zero when the current applied to the stepped convex induced voltage has the same shape as the induced voltage waveform, the thrust will be expressed as a constant straight line. However, if there is a phase difference, the thrust pulsation becomes large.

Furthermore, when a sine wave is used for the current, controllability is poor because the pulsation of the thrust is slow even when the phase difference is zero.

On the other hand, as explained in Fig. 1O, even when there is a phase difference in the flowing current, there is little variation in the thrust force, and even when the phase difference is zero, the thrust curve is a straight line9. Good sex.

From the above explanation, if the induced voltage generated in the coil is step-shaped or trapezoidal, it is possible to determine which It is possible to expect the effect of obtaining a nearly constant thrust output regardless of the position.

However, in the above embodiment, the first magnetic pole part is the mover,
The second magnetic pole part is used as a stator;
The magnetic pole part can be used as a stator, and the second magnetic pole part can be used as a movable element, and even in this case, the same effect can be expected.

〔Effect of the invention〕

According to the present invention, the optimum thrust can be generated by applying current in an optimum current pattern according to the induced voltage, thereby improving efficiency and controllability.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a plane parallel to the traveling direction of a linear motor used to implement the linear morph 1) control method according to an embodiment of the present invention, and FIG. 2 is a sectional view of a plane parallel to the traveling direction A front view, FIG. 3 is a schematic configuration diagram of a control circuit used for implementing the control method, FIGS. is the magnetic flux and induced voltage. A curve diagram representing the thrust force, Figure 1X7 is a waveform diagram of the induced voltage generated in the three-phase coil, Figure 8 is a diagram of the thrust force generated in the three-phase coil, and Figures 9 to 11 are graphs showing the waveform of the induced voltage generated in the three-phase coil. FIG. 6 is a diagram showing thrust force curves when the phase difference is ΔX. 1... Mover yoke, 2... Mover, 2a to 2C.
... Magnetic pole teeth, 3... Stator, 3a to 3e... Stator teeth, 4... Coil part, 48% 4C... Coil, 5.
...Dolly, 6.. Wheels, 7.. Yoke, 8.. Magnet, 9.. Frame, 10a.. Magnetic flux, 11a.. Induced voltage, 12a.. 11 currents, etc. 1 figure name 2 figure you 3 figure 10 bundle 5 figure destination 6 figure

Claims (1)

[Claims] 1. A first device having a plurality of tooth-shaped and uneven magnetic pole teeth made of a magnetic material and arranged at a constant length in the longitudinal direction.
The first magnetic pole part is composed of a magnetic pole part and a second magnetic pole part having a plurality of tooth-shaped uneven magnetic pole teeth made of a magnetic material and facing the first magnetic pole part with a slight air gap. The ratio of the number of magnetic pole teeth that are convex parts in the opposing part to the second magnetic pole part is 2.
:In a linear motor with a multiple of 3, the pattern of the current flowing through it is determined by the waveform of the induced voltage generated in the second or first magnetic pole part based on driving the first or second magnetic pole part. A method for controlling a linear motor, characterized in that: 2. In the item described in claim 1, when the waveform of the induced voltage generated based on driving the first or second magnetic pole part is step-like, the same phase is used as the energizing current waveform. A method of controlling a linear motor that causes a trapezoidal wave current to flow. 3. In the item described in claim 1, when the waveform of the induced voltage generated by driving the first or second magnetic pole part is a trapezoidal waveform, the same phase is used as the energizing current waveform. A method of controlling a linear motor that causes step-like current to flow.