JPH026281B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a position detection device for a magnetic levitation railway, and in particular, an electromagnet or a superconducting magnet (hereinafter both magnets are included) for levitation and propulsion on the traveling vehicle side. Equipped with a levitation and propulsion coil (simply referred to as an electromagnet) on the ground side, the vehicle is levitated by the electromagnetic action between the levitation electromagnet and the levitation coil when the vehicle is running, and the vehicle's running position is detected. The present invention relates to a position detection device in a magnetic levitation railway that propels a vehicle by applying an excitation current to a propulsion coil according to the position.

[Prior art]

FIGS. 1 and 2 are cross-sectional views of the car body and track of a magnetic levitation railway propelled by a ground primary type linear synchronous motor. 1 is a running vehicle, and this running vehicle 1
, propulsion electromagnets 2 and 3 and levitation electromagnets 4 and 5
and is provided. On the ground side, air-core propulsion coils 6, 7 and levitation coils 9, 10 are installed over the entire running section. 24 is a light projector provided on the vehicle side, 25 is a light receiver, and 26 is a detection plate provided over the entire track on the ground side, and these 24, 25, and 26 constitute a position detector. Reference numeral 8 indicates a track, and reference numeral 11 indicates a vehicle support body for when the vehicle is stopped.

Propulsion control of a running vehicle involves detecting the relative positions of the propulsion electromagnets 2 and 3 on the vehicle side and the propulsion coils 6 and 7 on the ground side using a light projector 24 and a light receiver 25 on the vehicle and a detection plate 26 on the ground. Then, the detection signal is transmitted to the ground side, and the excitation current is controlled to flow through the propulsion coils 6 and 7 in a phase that provides the most effective thrust, thereby generating a moving magnetic field.

The traveling vehicle causes the levitation coils 9 and 10 on the ground side to
An electromotive force proportional to the vehicle speed is generated, and the vehicle levitates due to the repulsive force between the magnetic field caused by this electromotive force and the magnetic field of the levitation electromagnets 4 and 5 on the vehicle side. For this reason, it is necessary to detect the position of the vehicle using a non-contact method, and a light detection method as shown in FIG. 1 has conventionally been employed.

However, the above-mentioned conventional position detection method has a structure in which recesses are provided on the bottom of the vehicle, which makes the vehicle structure vulnerable to vibration.Furthermore, a detection plate is provided along the entire track. There was a problem that the financial burden would be large because of the necessity.

Furthermore, Japanese Patent Application Laid-Open No. 56-157203 discloses that a search coil is provided to detect a 3n-order time harmonic voltage based on the reaction magnetic flux generated by a propulsion coil on the ground, and a position signal is obtained from the output voltage of this search coil. is proposed.

However, in this method, since the ground propulsion coil is used as a detection source, it is necessary to detect the phase change of the terminal voltage of the ground propulsion coil, and signal processing is required to detect the change regardless of this, so the complexity cannot be ignored.

[Purpose of the invention]

The object of the invention is to provide a simple, economical and accurate position sensing device for maglev railways.

[Summary of the invention]

In the present invention, electromagnets for levitation and propulsion are independently mounted on the running vehicle side, and coils for levitation and propulsion are provided on the ground side so as to face these electromagnets, respectively. A magnetic levitation railway position detection device that levitates a vehicle through electromagnetic action between an electromagnet and a levitation coil, detects the vehicle's running position, and propels the vehicle by applying an excitation current to the propulsion coil according to the detected position. , a detection coil that detects the magnetic field created by the voltage induced in the levitation coil as the vehicle runs is placed on the upper side of the vehicle facing the levitation coil, where τ is the magnetic pole pitch of the levitation coil and n is an arbitrary natural number. A bridge circuit arranged at two positions separated by τ×n+τ/2 in the running direction and including the two detection coils on two sides, and a high-frequency oscillator for supplying high-frequency power for power supply to this bridge circuit. a switching means that connects the high-frequency oscillator to the bridge when the vehicle is running at low speeds and when the vehicle is stopped, and short-circuits the power terminals of the bridge circuit when the vehicle is running at high speeds; It is characterized by comprising a signal processing means for obtaining a position detection output.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIGS. 3, 4 and 5.
This will be explained using figures. FIG. 3 is a diagram showing the arrangement and output waveform of a detection coil for position detection, and FIG. 4 is a diagram showing an example of a signal processing means for processing a detection signal to generate a position signal. 12 and 13 are detection coils provided at two positions on the top of the vehicle so as to face the levitation coil 9 on the ground side, and the distance between the centers of both detection coils in the vehicle running direction is τ The magnetic pole pitch of the coil 9 is selected to be τ×n+τ/2, where n is an arbitrary natural number. FIG. 3 shows the case where n=1. Detection coil 1
Reference numerals 2 and 13 denote air-core coils, which are made to have the same size as the levitation coil 9 or a slightly smaller shape, and are installed on the top side of the vehicle at a position facing the levitation coil 9 for good magnetic coupling. The number of turns of the detection coils 12 and 13 depends on the gap length between the levitation coil and the detection coil, the number of turns of the levitation coil, etc.
It was practical for 200 to 500 turns.

The mounting positions of the detection coils 12 and 13 are preferably selected so that when one detection coil is in the maximum coupling state, the other detection coil is in the minimum coupling state.

The following two methods can be considered for detecting the relative position between the propulsion electromagnet on the vehicle and the propulsion coil on the ground by arranging two detection coils at positions facing the levitation coil. The first method is to use detection coils 12 and 13 installed on the vehicle to detect the magnetic field created by the induced voltage generated in the levitation coil 9 on the ground by the levitation electromagnet 4 on the vehicle as the vehicle travels. be. At this time, the voltage waveforms detected by the detection coils 12 and 13 are as shown in 12a and 13a in FIG. 3. 12a is the output waveform of the detection coil 12, 13
a shows the output waveform of the detection coil 13. The detected voltage waveform when the traveling vehicle 1 moves in the direction of the arrow is, since the detection coils 12 and 13 are installed at positions separated by τ+τ/2 in the traveling direction from the magnetic pole pitch τ of the levitation coil 9. When one detected voltage value becomes the maximum, the other becomes the minimum value.

FIG. 4 shows an embodiment of the signal processing circuit in this case. The two detection coils 12 and 13 have variable impedance 14 and fixed impedance 15.
The differential voltage is detected by bridge-connecting the two. The variable impedance 14 is adjusted in a state where there is no induced voltage in the levitation coils 9a and 9b, so that the voltage between the bridge output terminals B and C becomes zero. As mentioned above, when the vehicle is running and the detection coil 12 generates the maximum voltage, the voltage generated by the detection coil 13 is the minimum, so at this time the maximum voltage difference occurs between the bridge output terminals B and C, and then When the vehicle moves, detection coil 1
3 is the maximum voltage, and when the detection coil 12 is the minimum voltage, the opposite differential voltage between the bridge output terminals B and C is the maximum. In this way, bridge output terminals B and C
An output close to a sine wave is generated, and this output is amplified by an amplifier 16, and this amplifier output is waveform-shaped by a waveform shaping circuit 17 and sent as a position signal to the propulsion coil on the ground. This method has high measurement sensitivity when the vehicle is running at high speed, but
There is an inconvenience that detection sensitivity is low when driving at low speeds, and detection becomes difficult when the vehicle is stopped.

Therefore, the method used when the vehicle is running at low speed or when the vehicle is stopped is a method in which the detection coil is excited with a high-frequency current and the change in mutual inductance with the levitation coil is detected by the change in the excitation current of the detection coil. An example circuit diagram is shown in FIG. A high frequency oscillator 18 generates alternating current with a frequency of about 5 to 50 KHz,
It passes through the isolation transformer 19 and then the changeover switch 2.
0 contacts a and c, the bridge-connected detection coils 12 and 13 are excited. Detection coil 1
Changes in the mutual inductances of transistors 2 and 13 depending on the vehicle position are output as an unbalanced signal between bridge output terminals B and C. This output is sent to the amplifier 16
This amplifier output is amplified by the waveform shaping circuit 17.
The waveform is shaped into a position signal. The changeover switch 20 is provided so that it can also be used as the induced voltage detection method shown in FIG. 4 by connecting contacts b and c. By setting the changeover switch 20 to the a and c sides when the vehicle is running at low speeds and when the vehicle is stopped, and connecting between b and c when the vehicle is running at high speeds, a highly sensitive detection method can be achieved in all speed ranges. .

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to detect the vehicle position for each levitation coil by using the levitation coils that are always installed in magnetic levitation railways for the purpose of levitation of vehicles. In addition to eliminating the need for equipment that spans the entire track, such as a detection plate,
Since the processing of the detection signal is simplified, the device can be economically inexpensive, and since it is not necessary to provide a recess on the bottom of the vehicle, the vehicle structure can be made resistant to vibrations.

[Brief explanation of drawings]

FIG. 1 is a sectional view for explaining the prior art, FIG. 2 is a side view of the vehicle and track shown in FIG. 1, FIG. 3 is a diagram showing the detection coil arrangement and output waveform according to the present invention, and FIGS. 4 and 5. 2A and 2B are circuit diagrams of embodiments of signal processing according to the present invention, respectively. 1... Vehicle, 2, 3... Propulsion electromagnet, 4, 5
...levitation electromagnet, 6,7...propulsion coil,
9, 10... Levitation coil, 12, 13... Detection coil, 14... Variable impedance, 15...
Fixed impedance, 16...Amplifier, 17...
Waveform shaping circuit, 18... High frequency oscillator, 20...
Changeover switch.

Claims (1)

[Scope of Claims] 1. Electromagnets for levitation and propulsion are mounted independently on the running vehicle side, coils for levitation and propulsion are provided on the ground side so as to face these electromagnets, respectively, and when the vehicle is running, A magnetic levitation type railway that levitates a vehicle through electromagnetic action between a levitation electromagnet and a levitation coil, detects the vehicle's running position, and propels the vehicle by passing an excitation current to the propulsion coil according to the detected position. In the position detection device, a detection coil that detects the magnetic field created by the voltage induced in the levitation coil as the vehicle runs is placed on the upper side of the vehicle facing the levitation coil, where τ is the magnetic pole pitch of the levitation coil and n is an arbitrary number. A bridge circuit is arranged at two positions separated in the running direction by τ×n+τ/2 as a natural number, and includes the two detection coils on two sides, and a bridge circuit for supplying high-frequency power for power supply to this bridge circuit. a high-frequency oscillator, a switching means for connecting the high-frequency oscillator to the bridge when the vehicle is running at low speed and when the vehicle is stopped, and short-circuiting the power terminals of the bridge circuit when the vehicle is running at high speed, and taking out the unbalanced output of the bridge circuit. What is claimed is: 1. A position detection device for a magnetic levitation railway, comprising a signal processing means for obtaining a position detection output of a vehicle.