JPS6133348B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control device for a linear motor, and particularly relates to a propulsion winding for generating a moving magnetic field and a field for generating thrust opposed to the propulsion winding. The present invention relates to a linear motor control device that is optimal for a linear synchronous motor equipped with magnetic poles.

[Conventional technology]

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 a conductive plate is installed on the ground side to levitate it while traveling, a linear synchronous motor uses the superconducting magnet as a field. (below
(referred to as LSM) is considered advantageous.

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

Depending on the method of excitation of the propulsion winding, LSMs are classified into self-limiting LSMs and other-limiting LSMs. A self-limiting LSM, like a so-called thyristor motor, detects the relative position between the propulsion winding and the field, and performs excitation based on the result. In principle, a multi-mode LSM does not perform such position detection, but instead performs excitation in accordance with the frequency of the built-in oscillator.

Self-limiting LSMs always perform relative position detection as described above, which ensures synchronization from startup to acceleration and deceleration to stop, allowing for stable operation, which is why this method is currently considered convenient for LSMs.
For position detection used in self-limiting LSMs, optical methods and cross-guidance methods are being considered.

A sinusoidal current is applied to the propulsion winding of the LSM in accordance with the position-detected synchronization signal. The use of sine waves here is required to move the moving body smoothly. Accurate speed is required to create this sine wave. Conventionally, this speed has been determined by measuring the time until the point of change in the position signal. Therefore, if each position signal is not accurate, the speed will change and an accurate sine wave cannot be generated. Experimentally, considerable accuracy can be obtained by adjusting the position detector and the detected object, but accuracy cannot be obtained at distances of hundreds of kilometers, such as on commercial lines. This will be explained below based on the drawings.

FIG. 1 is a schematic diagram showing an example of a conventional linear motor propulsion system, and FIG. 2 is a block diagram of its synchronous control section.

Field pole SCM and position detector PD are on the moving body TR.
A propulsion winding LSM is installed on the ground side.
and a detection plate PMR of the position detector PD. Note that the propulsion winding LSM is driven by three-phase alternating current. In addition, position detector PD and detected plate PDR
The position detecting means includes the above.

The position signal PDS detected on the mobile body TR by the position detector PD of the position detecting means is sent wirelessly to the ground side. This position signal PDS is shown in Figures 4 to 7.
As shown by U, V, and W in the figure, this is a three-phase position detection signal in the form of a rectangular wave with an electrical angle of 180 degrees. These state changes of rising and falling of the signal PDS occur when the position detector PD detects that the detection plate PDR is installed, and by measuring the interval time of the state change, The speed of the installation section of the detection plate PDR that provides rising and falling signals is determined. Square waves, trapezoidal waves, and sine waves are generally used as the shape of the current flowing through the propulsion winding LSM, but sine waves are preferable because they cause less thrust pulsation. The position detector signal PDS is taken into the speed calculator 1, and the speed calculator 1 calculates the values shown in Figures 4 to 7.
Find the speed V as V ₁ , V ₂ , V ₃ ..., Vn,
This speed produces a sine wave as shown in Figure 8.
A sine wave is generated by the synchronization control 2 by synchronizing SYCS with the rising and falling edges of the position signal PDS. This synchronous control section 2, a multiplier 3, a propulsion current setting device 4, and a cyclone converter 10, which will be described later, constitute a driving means. This sine wave is sent to a multiplier 3, and by setting a propulsion current i to be applied to the sine wave using a propulsion current setting device 4, a current pattern ip can be obtained from the multiplier 3. This current pattern ip is sent to the cycloconverter 10 and drives the propulsion winding LSM. As shown in FIG.
Ideally, the voltage Ea induced in the LSM and the current ipx flowing through the propulsion winding should be controlled so that they are in the same phase (propulsive force is expressed as Eax×ip×cosθ, and when they are in phase, the maximum propulsion ).

Each of FIGS. 4, 5, 6, and 7 shows an example of a speed calculation method that can be performed by the speed calculation unit 1 depending on how the ignition signal is obtained. Figure 4 is 3
This is a method of calculating the speed V every 60 degrees using the rising and falling of other phases in U, V, and W of the phase signals. Figure 5 shows a method of calculating speed every 120 degrees using the rising edges of the other phases of the three-phase signals U, V, and W. Figure 6 shows the rising edges of the same phase among the three-phase signals U, V, and W. Every 180 degrees using the falling edge, Figure 7 uses the in-phase rising edge of the three-phase signals U, V, and W.
This method calculates the speed every 360 degrees.

[Problem to be solved by the invention]

In order to improve the accuracy of speed prediction, it is preferable to increase the number of pulses as shown in FIG. 4, but this has the drawback that the speed error in the high speed range reaches several tens of percent. Moreover, in the examples shown in FIGS. 6 and 7, on the contrary, the speed error increases in the low speed range (because the interval becomes longer when the position detection signal is at a low speed). In this way, the position signal PDS is unbalanced between in-phase signals due to the installation spacing of the detection plates due to the relationship between the installation error of the position detector PD on the moving body TR and the detection target PDR on the ground, and the three-phase signal Errors occur due to differences in the installation intervals of the position detectors on the moving body. When speed is determined using the conventional method, the effects of these errors appear directly as speed errors.

When the sine wave generated by the speed calculation result and the position signal match without any speed error, it will be as shown in Figure 8, and if there is a speed error, the synchronized sine wave SYCS will be distorted as shown in Figure 9. It becomes a waveform.

In the example shown in FIG. 8, the section travel time t is determined from the position signal PDS, and the speed V is determined by dividing the measured section length. If the vehicle is running at a constant speed, the time it takes to pass the next 180 degrees and 360 degrees from the determined speed is the same, so a sine wave that matches this time is output. If it is accelerating or decelerating, calculate the acceleration/deceleration and calculate the next 180 degrees or 360 degrees.
It outputs a sine wave by predicting the transit time of the degree.

In the example shown in FIG. 9, the sine wave outputted by the velocity calculation result in which the velocity calculation result every 180 degrees and the position signal are different is interrupted midway by the position signal.

In this way, if the rising and falling signals between the three-phase signals are used as they are to calculate the speed, there is a drawback that the smaller the angle or the higher the speed, the larger the speed calculation error becomes.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for controlling a linear motor that performs control by obtaining an accurate speed signal using the average value of the outputs of a plurality of position detectors.

[Means for solving problems]

A linear motor control device according to the present invention that solves the above problems includes a propulsion winding that generates a moving magnetic field so as to form a pair on the orbit and a moving body, and a propulsion winding that is opposed to the propulsion winding and generates thrust. A field winding is provided, and a position detection means including a position detector and a detected object detects the position of the moving object and outputs a multiphase position detection signal, and the position detection signal is in a state. A speed calculator that calculates the section speed of the moving object passing through the installation section of the detected object based on the changing interval time, and a speed calculator that takes the calculation results from the speed calculator and uses the calculation results to calculate the phase number of the position detection signal. averaging means for calculating the average speed by successively dividing the position detection signals in the order in which they occur, and for calculating the average speed by removing the phase loss when the position detection signal has an open phase; a synchronization control section comprising driving means for generating a current pattern and moving the movable body while synchronizing the propulsion winding and the field winding based on the average speed from the switching means; It is characterized by:

[Effect]

First, by measuring the interval time at which the state of the position detection signal from the position detection means changes, and dividing by this the interval in which the object to be detected is installed, the velocity in that interval can be determined, and this is determined by a velocity calculator. Since this calculation result causes an error as described in the problem section, the average velocity is obtained by dividing the calculation result by the number of phases of the position detection signals successively in the order in which the position detection signals are generated using an averaging grenade. Based on this average speed, a driving means generates a current pattern while synchronizing the propulsion winding and the field winding to move the movable body.

This allows stable speed control.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 10 is a block diagram of a synchronous control section for a linear motor propulsion system to which the present invention is preferably applied. This embodiment differs from the configuration shown in FIG. 2 in that averaging means consisting of an open phase detection section 5 and an averaging calculation section 6 are newly added.

Based on the position detection signal PDS, three-phase signals consisting of V ₁ , V ₂ , . . . , Vn as shown in FIGS. 4 to 7 are obtained. Therefore, the speed calculation output from the speed calculation unit 1 is taken into the averaging calculation unit 6, and the averaging calculation unit 6 performs averaging of the three phases. In this case, the averaging performed by the averaging calculation section 6 is performed so as to satisfy the following equation.

Average speed = V ₁ +V ₂ +V ₃ /3, V ₂ +V ₃ +V ₄ /3, V ₃ +V ₄ +V ₅ /3, ..., Vn _-2 +Vn _-1 +Vn /3, Vn _-1 +Vn + V ₁ /3 ,...... (1) When averaging as shown in the above equation, the average value is taken every time one position signal is output, so that the average value can be obtained continuously. Suppose that all blocks are grouped together as V ₁ +V ₂ +V ₃ /3, V ₄ +V ₅ +V ₆ /3...(2
) is inappropriate because it creates time vacancies.

Also, if one of the three phases has an open phase, an error will appear in the average value, so in the case of an open phase, the denominator of equation (1) should be changed to 2.
The averaging calculation unit 6 is provided with a function to calculate the average value, and an open phase detection unit 5 is also provided which detects an open phase and sends a command to the averaging calculation unit 6. If the sine wave obtained in this case is generated in three phases at once in synchronization with any phase that is not open, even if the phase is open, it will not affect the running.

〔Effect of the invention〕

As is clear from the above, according to the present invention, stable linear motor control without speed errors can be performed.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of a conventional linear motor propulsion system, Fig. 2 is a block diagram of the synchronous control section of the system shown in Fig. 1, Fig. 3 is an explanatory diagram of the propulsive force of the linear motor, and Fig. 4 is An explanatory diagram of speed calculation at 60 degrees, Figure 5 is an explanatory diagram of speed calculation at 120 degrees,
Figure 6 is an explanatory diagram of speed calculation at 180 degrees, Figure 7 is an illustration of velocity calculation at 360 degrees, Figure 8 is a waveform diagram of the output sine wave when there is no variation in the position detection signal, and Figure 9 is the position detection diagram. FIG. 10 is a waveform diagram of an output sine wave when there is variation in the signal, and No. 10 is a block diagram of a synchronous control section for a linear motor propulsion system suitable for implementing the present invention. 1...Speed calculator, 2...Synchronization control unit, 3...
Multiplier, 4...Propulsion current setting device, 5...Open phase detection unit, 6...Averaging speed calculation unit, 10...Cyclo converter, TR...Moving body, SCM...Field pole,
PD...Position detector, PDR...Detected plate, LSM...
…propulsion winding, PDS…position detection signal, ip…current pattern.

Claims (1)

[Claims] 1 A propulsion winding that generates a moving magnetic field and a field winding that generates a thrust are arranged in pairs on the orbit and on the moving body, and
A position detecting means including a position detector and a detected object detects the position of the moving object and outputs a multiphase position detection signal, and the multiphase position detection signal is detected based on the interval time in which the state changes. a speed calculator that calculates the section speed of the moving object passing through the installation section of the detection object;
The calculation result from the speed calculator is taken in, and the calculation result is successively divided by the number of phases of the position detection signal in the order of generation of the position detection signal to obtain the average speed. an averaging means for obtaining an average speed by removing the phase loss when the phase loss occurs; 1. A control device for a linear motor, comprising: a synchronous control section comprising a drive means for generating electricity and moving the movable body.