JPS6023599B2 - Linear motor control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synchronous control system for a near-synchronous motor, which is equipped with a propulsion winding for generating a moving magnetic field and a field pole for generating thrust in opposition to the propulsion winding. It is.

Recently, linear motors have been used as one of the propulsion methods for ultra-high-speed railways.
Evening propulsion is attracting attention.

In the so-called superconducting magnetic levitation system, in which a superconducting magnet is mounted on a moving vehicle and a levitation winding or conductive plate is installed on the ground side to levitate the vehicle while traveling, the superconducting magnet is used as the field. Asynchronous mode evening (hereinafter referred to as LS)
M) is considered advantageous. The propulsion winding of the LSM has a multi-phase configuration, generates a moving magnetic field, and obtains propulsion force through interaction with the field.

Self-control type LSM and other-control type LS depending on the way of excitation of the propulsion winding.
It is classified as M.

A self-limiting LSM, like a so-called thyristor motor,
The relative position between the propulsion winding and the field is detected and excitation is performed based on the result.In principle, the other type LSM does not perform such position detection, but corresponds to the frequency of the built-in oscillator. Excitation is performed by self-control LS
Since M always performs relative position detection as described above, it is reliably synchronized from startup to acceleration and from deceleration to stop.
Allows for stable driving. For this reason, this method is considered advantageous for the current LSM. On the other hand, since the pond type LSM does not perform relative position detection, there is a risk of step-out during the above-mentioned continuous rotation. Many position detectors have been considered for use in self-limiting SMs, such as an optical method, a cross-induction method, and a method using the magnetic field of field poles.

In the conventional synchronous control of LSM, the signal from the position detector is assumed to be correct and accurate and is used as is for control, so there is a drawback that if the signal accuracy is poor, the thrust force will be reduced. SUMMARY OF THE INVENTION An object of the present invention is to provide a control method that indirectly uses a position detector signal to obtain stable thrust with less fluctuation in thrust. The present invention oscillates a stable frequency matching the speed of the moving body and matches the phase with a position detector, thereby obtaining stable thrust without sudden changes.

The present invention will be explained below with reference to the drawings. Figure 1 shows the conventional LS
In one embodiment of M, a field pole SCM and a position detector PD are provided on the moving body TR, and three-phase (U, V, W phase) propulsion windings are installed on the ground with M and the detection plate PDR of the position detector. This is a three-phase drive system.

FIG. 2 is a block diagram of the synchronization control.

When controlling on the ground, the position signal POS detected by the position detector PD on the moving body is transmitted to the ground by radio as a position signal PDS. The position signal PDS is input as a three-phase square wave with an electrical angle of 180 degrees.

By measuring the time interval between the rise and fall of this signal, a speed signal VS is obtained by a vehicle speed calculating section V. Square waves, trapezoidal waves, and sine waves are usually used as the shape of the current flowing through the thrust winding, but sine waves are preferable because they cause less pulsation. The synchronization control unit SYC is configured so that the voltage Ea shown in Fig. 3, which is induced in the propulsion coil on the ground by the field pole on the moving body, and the current ipx flowing through the propulsion winding are the same (maximum thrust is achieved when they are in phase). ) is ideally controlled. Position detection signal P
When the DS is accurate and there is no variation, as shown in Figure 4a,
When there is variation, a sine wave like that shown in FIG. 4b occurs.
Figure 4a shows the section travel time t determined from the position signal PDS.
The speed signal VS is obtained by dividing the measurement section length.

If you are driving at a constant speed, the next 180 degrees or 3
Since the time for passing through 60 degrees is also the same, a sine wave matching this time is output. If it is accelerating (or decelerating), the acceleration (
(or deceleration), predicts and calculates the next 180 degree passage time, and outputs a sine wave SYCS. FIG. 4a shows a case where the position detection signal is normal and the output sine wave is also normal.

Fig. b shows the output sine waveform SYCS when there is variation in the position detection signal PDS.

Since the speed calculation results are different for every 180 degrees, the next 1800 degrees
Even if a predicted sine wave is output, it does not match the rising or falling signal of the position signal for synchronization, so as a result, the waveform is forcibly truncated using the position signal to achieve synchronization.

Variations of about 10 degrees occur due to mounting accuracy of the detector and the detected object, transmission delays, predictive calculations, etc. Returning to Fig. 2, the synchronization control unit SYC generates the synchronized sine wave (constant peak value) SYCS as described above, and the thrust value is given by the thrust command unit i is added to this by the counter MULl. This results in a current pattern lps (current pattern generation part ip) flowing through the propulsion winding,
A power converter (not shown) converts this current pattern ip
A current flows through the propulsion winding as per s, and the desired propulsion force is obtained.

In such a system, if there is any disturbance in the position signal, it will directly generate a distorted current pattern as explained in FIG. 4b, and the thrust of the linear motor will also vary.

Therefore, in order to prevent this, as a position detector,
It is necessary to use stable equipment with high precision and no noise or variation. FIG. 5 shows an embodiment according to the present invention.

The speeds V, .about.Vn are calculated from the position signal PDS by determining the section traveling time in the same way as in the conventional method.

Conventionally, speed was calculated based on one section of travel, but by calculating the average speed from the speed of multiple sections, a stable speed V can be achieved.
It becomes S. The speed calculation unit V performs this calculation. In particular, when noise is mixed in or a phase is lost, the conventional speed calculation results output a speed that is different from the normal speed, so the output sine wave is abnormally disturbed. However, by averaging as in this example, the disturbance is suppressed. It becomes less.

The synchronous waveform generator SYCP outputs a three-phase sine wave (square wave) SYCPS that is not synchronized by the average speed VS.

If this sine wave remains as it is, synchronization will not be achieved, so as shown in FIG. QT and the adder ADD correct the original speed signal VS according to the plurality of average values OTS of QS, and sequentially make the phase difference zero. That is, in the conventional technology explained in FIG.
S, and generate the sine wave SYCS using the method explained in Figure 4.
As a result, the output has a position signal PD
The disturbance of S appears directly. On the other hand, in the present invention, the synchronous waveform generator SYCP outputs a sine wave with a frequency corresponding to the speed. In other words, as in the embodiment, the speed signal VS or the elapsed time TS corresponding to the speed is t,
It is a sine wave with a frequency corresponding to a signal corresponding to the speed, such as 10t20...tn)/n. Then, this frequency is corrected using the average value QTS of the phase difference. Specifically, the original speed signal VS is corrected. Therefore,
The output of the synchronous current waveform generation node SYCP is a sine wave with no waveform distortion.

Even if there is a disturbance in the position signal PDS, the result is only a change in the speed calculation value and a change in the frequency of the sine wave. Here, the correction of the speed signal VS (or it may be the elapsed time S as described above) by the average value QTS of the phase difference has two meanings.

That is, the first step is to synchronize with the position signal PDS. If the output sine wave lags or leads the position signal PDS (even if there is no average error in frequency), the frequency is transiently increased or decreased to achieve coincidence. Second, as a result of the above, the speed error (that is, the frequency difference between the position signal POS and the sine wave output) is also controlled to be zero on a steady basis.
The sine wave thus obtained essentially does not have the distortion shown in FIG. 4b.

It is not necessary to employ this method over the entire range from the time the linear motor is started.

Initially, it is convenient to start up in the manner described in FIG. That is, when generating a synchronized waveform for the first time from the speed VS, it is preferable to start it in synchronization with the position signal PDS. Furthermore, if a control system is used that detects synchronization and also uses a position signal to pull in synchronization when synchronization occurs, it will be more stable. When there is a delay in the entire control system, it is necessary to advance the current pattern ip from the position signal PDS.

In this case, the square wave advanced by 6S from the position signal PDS by the phase advance unit 6 in FIG. This is possible by adding compensation with ADD2. According to the embodiments described above, it is possible to output a stable current pattern even if there is noise or variation in the position signal.

Furthermore, the counterfeit signal may be of lower accuracy than the conventional one. Therefore, it is conceivable to use a simple means such as not providing a special position detector and using the voltage induced in the propulsion winding by the field pole as the position detector. Furthermore, if one or two of the three phases of the position detector are open while the position detector is running, the conventional method generates a sine wave in accordance with the rise and fall of the position detector of each phase, so if the phase is open, We were unable to output a sine wave and had to stop the moving object, but if we made the speed calculation independent for each phase, the sine wave would output one finger in three phases, so it would be possible to output a sine wave without stopping the moving object. It's okay. According to the present invention, current commands (patterns) for linear synchronous modes can be reliably generated in synchronization.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a schematic configuration of an example of a linear motor, Fig. 2 is a block diagram of conventional synchronous control of a linear motor, Fig. 3 is an explanatory diagram of synchronization of a linear motor, and Fig. 4 is a synchronous sine control system using a conventional control method. FIG. 5 is an explanatory diagram of a wave generation method, FIG. 5 is an embodiment of a linear motor control block according to the present invention, FIG. 6 is an explanatory diagram of phase difference detection, and FIGS. 7 and 8 are other embodiments of the present invention. It is a block diagram. TR...Moving object (vehicle), SCM...Field pole, PD...Position detector, LSM...Propulsion winding, PDR...Detected object Board, PDS...
・Position detection signal, V...Vehicle speed calculation section, AD
D and ADD2...addition section, SYCP...
・Synchronized current waveform generation section, MUL... Multiplication section, q
...... Phase difference detection section, i... Thrust command section, QT.
. . . Phase difference averaging section, 6 . . . Phase advancing section. Leopard Diagram Chrysanthemum Z Diagram Tsutomu 3 Diagram 4 Skin Tsutomu Diagram Similar Tsutsuzu Diagram Admiring Diagram 7 Tsutomu Diagram

Claims (1)

[Claims] 1. In a linear synchronous motor in which one of the propulsion winding and the field pole is installed on a moving body and the other is installed on a track, a sine wave current waveform that serves as a current command to feed the propulsion winding. means for continuously outputting at a frequency corresponding to the speed of the moving body, means for detecting the position of the moving body, and means for comparing the phase of the current waveform with a signal related to the output of the position detecting means. and means for correcting the frequency of the sinusoidal current waveform in response to the output of the comparing means. 2. The linear motor control system according to claim 1, wherein the correction means is configured to respond to an average value within a predetermined period of outputs of the phase comparison means. 3. In a linear synchronous motor in which one of the propulsion windings and field poles is installed on a moving body and the other on a track, a sine wave current waveform serving as a current command to feed the propulsion winding is adjusted to the speed of the moving body. means for continuously outputting at a frequency corresponding to the position of the moving object; means for detecting the position of the moving object; means for comparing the phase of the current waveform with a signal related to the output of the position detecting means; and the output of the comparing means. a linear motor comprising means for correcting the frequency of the sinusoidal current waveform in response to the current waveform, and a phase advancing means provided in a correction control system including the correction means and advancing the sinusoidal current waveform by a predetermined phase. control method.