JPS5833796B2 - Linear motor control method - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a synchronous control method for a linear 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. be.

Recently, linear motor propulsion has been attracting attention as one of the propulsion methods for ultra-high-speed railways.

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 it while traveling, a linear synchronous motor (hereinafter referred to as LSM) is used to field the superconducting magnet. )
is considered advantageous.

The propulsion winding of the LSM has a multi-phase configuration, generates a moving magnetic field, and obtains thrust through interaction with the field.

Self-control type LSM and other-control type LS depending on the method 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 instead uses the frequency of the built-in oscillator. Excitation is performed in response to the

Since the self-control type LSM always detects the relative position as described above, synchronization is ensured from startup to acceleration and deceleration to stop, and stable operation can be performed, so this method is considered advantageous for current LSMs. .

Therefore, as many position detectors as the number of self-limiting LSMs are provided for each phase.

A sinusoidal current is applied to the propulsion winding of the LSM in accordance with the position-detected synchronization signal.

Currently, position detectors are provided for each phase.

Therefore, a large number of position detectors and detection plates are required.

Furthermore, since electrical control is performed independently according to the position detector of each phase, an unbalanced current is generated, and harmonics and induction noise are likely to occur.

On the other hand, it is known in the field of thyristor motors to multiply a position signal for one phase to produce a square wave signal for three phases.

However, in the case of a linear synchronous motor, if the three phases are not accurately balanced, as mentioned above, high frequency and induction noise will be generated, which is undesirable.Furthermore, in a linear motor vehicle, pulsation due to the thrust pulsation is likely to occur. .

An object of the present invention is to provide a control method that can easily create a sinusoidal current pattern in which three phases are accurately balanced from a position signal for one phase, and that can reduce vibrations, harmonics, and induction noise of a linear motor. be.

A feature of the present invention is that a storage means is provided for storing the peak value signals of three phases of sine waves each electrically having a phase difference of 120 degrees from each other for each subdivided electrical angle. A means is provided for calculating a signal corresponding to the speed of the moving object using the output of the detector, and based on this and the position detection signal for one phase, the peak value signals for the three phases are sequentially read out, and the peak value signals for the three phases are read out. The idea is to generate a current pattern.

That is, the reading speed of the peak value signal is determined by calculating the speed or a signal corresponding thereto, and synchronization can be easily achieved using the position signal for one phase.

Therefore, in the obtained current pattern, the three phases are reliably balanced both transiently and steadily, and the above-mentioned drawbacks can be alleviated.

Furthermore, there is no need to be aware of disturbances in balance due to changes in the speed of the linear synchronous motor, and it is easy to simply read out the stored values.

The present invention will be explained below with reference to Examples.

Figure 1 shows an example of a conventional LSM, in which a field pole SCM and a position detector PD are provided on a moving body TR, and a propulsion winding LS is installed on the ground.
This is a three-phase drive system that includes M and a detection plate PDR of a position detector.

FIG. 2 is a synchronization block diagram thereof.

The position signal PDS detected on the mobile object is sent to the ground by radio.

The position signal is input as a three-phase square wave with an electrical angle of 180 degrees.

By measuring the time intervals between the rise and fall of these signals, the speed calculation section (2) calculates the speed vS in that section.

Square waves, trapezoidal waves, and sine waves are generally used as the shape of the current flowing through the propulsion windings, but sine waves are preferable because they cause less thrust pulsation.

A sine wave that matches this speed is generated as 5ycs by the synchronization control unit SYC in accordance with the position signal, and this sine wave is multiplied by the propulsion current iS (generated by the propulsion current command unit i) to be passed. Generation of current pattern flowing through the winding i, 5
(Current pattern generation part ip).

MUL is a multiplication part. Synchronous control is performed so that the voltage Ea induced in the propulsion winding LSM on the ground by the field pole SCM on the moving body shown in Fig. 3 and the current 1px flowing in the propulsion winding are in phase (the propulsion force is Ideally, it would be possible to control the

FIG. 4 shows an embodiment of a control method for a three-phase LSM according to the present invention.

The difference from the conventional example is that the synchronization control unit SYC outputs a three-phase sine wave in synchronization with one position signal PDS.

For the sine wave output, store the three phases of the sine wave shifted by 120 degrees in a storage element (for example, P-ROM), and then increase the speed.
This is possible by changing the generation time of the sine wave.

In other words, the frequency of the sine wave is changed according to the speed, and the details are divided into 128 and 256 (8 digit binary numbers) for 180 electrical degrees and the wave height values are memorized. , are sequentially read out at a speed corresponding to the calculated speed.

Outputting three-phase sine waves in synchronization with one position signal has the following effects.

(1) The number of position detectors and detected objects can be reduced.

(2) Since no imbalance occurs in the three-phase sine wave, harmonics and induced noise are reduced.

(3) When the original position signal fails, there is no pattern output for all three phases, so vehicle vibrations due to open-phase operation as in the conventional case do not occur.

If it is necessary to continue outputting the pattern, it is possible to switch to a position detector of another phase.

[Brief explanation of the drawing]

Figure 1 is a diagram showing an example of a conventional linear motor;
FIG. 3 is an explanatory diagram of the propulsion force of the linear motor, and FIG. 4 is a block diagram of the synchronous control of the linear motor according to an embodiment of the present invention. TR...Moving object (vehicle), SCM...
Field pole, PD...Position detector, PD, R...
...Detected plate of position detector, LSM... Propulsion winding, SYC... Synchronous control section, ■...
Speed calculation unit, i... Thrust command unit, MUL...
. . . Multiplication section, i, . . . Current pattern generation section.

Claims (1)

[Claims] 1 Synchronize the propulsion winding and the field winding in a three-phase linear synchronous motor in which either the propulsion winding or the field winding is installed on the moving body and the other is installed on the orbit. a position detector provided for the purpose, a storage means for storing the signal for each electrical angle, which is obtained by subdividing the peak value signal of a sine wave for three phases having a phase difference of 120 degrees electrically from each other; means for calculating a signal corresponding to the speed of the moving object based on the output of the detector; and 3 subdivided signals stored in the storage means based on the one-phase position signal from the position detector and the speed corresponding signal. A control method for a near motor, comprising means for sequentially reading out peak value signals for each phase, and means for generating a three-phase current pattern based on the read out peak value signals.