JPS601826B2 - Linear motor stop position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a relative position detection device between a propulsion coil and a field pole of a linear synchronous motor.

In general, a linear synchronous motor starts synchronously at the time of starting, so it detects the stop phase of the traveling object, excites the propulsion coil at a phase corresponding to the stopped phase, and starts the motor.

After starting, position detection is no longer necessary by using induced voltage or by operating with a pond control system. Conventionally, the method of position detection has been to use a pair of light emitting parts and light receiving parts placed for each propulsion coil. Light-based devices, such as those in which a light-receiving part detects the light from a light-emitting part, or those in which a light-emitting part and a light-receiving part are installed across the running path, and the traveling object detects the presence of the light by cutting off the light. Detection has been made. However, there are measures to prevent contamination and pollution of the light receiving part and the light emitting part.
Furthermore, since it had to be installed along the entire line, there were maintenance and cost problems. An object of the present invention is to provide a more accurate stop position detection device for practical use of near-vehicle motor cars.

A feature of the present invention is that the ground propulsion coil is excited and the magnetic flux is detected by a sensor on the traveling body to determine the position.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, there is a running body 15 on three-phase AC propulsion coils U-phase 10 and 13, V-phase 11 and 14, and W-phase 12, which are laid on a roadbed 17.

A magnetic sensor 16 is installed near the propulsion coil on the traveling body.
are arranged so that the relative position with respect to the field pole 18 can be seen. The pitch of the magnetic sensor 16 is the pitch of the ground propulsion coils 10, 11, 12.
, 13, 14 or the pitch of the field poles 18 or smaller. The number of magnetic sensors may be selected depending on detection accuracy. Under these circumstances, one phase of the ground propulsion coil, for example, U-phase 10, 13, is excited with DC or AC.

The combined magnetic field with the DC magnetic pole on the traveling body or the changing magnetic field of the propulsion coil generated at this time is measured by a sensor, and the stopping position is determined.
Note that synchronous starting means starting by exciting the propulsion coil in the same phase as the magnetic flux 19 of the field pole. Next, another embodiment will be explained with reference to FIG.

The three-phase AC propulsion coils are installed on the roadbed 17, U-phase 10 and 13, V-phase 11 and 4, and W-phase 13, on which the traveling body 15 is installed.
There is. A magnetic sensor 26 is placed near the propulsion coil on the traveling body. One sensor or several sensors are placed at a pitch that indicates the relative positional relationship between the field pole and the propulsion coil, and the vehicle is fixed to the roadbed with a mechanical brake, or ground propulsion is performed using an excitation current that does not move the vehicle. The coil is excited with three-phase AC. At that time, the stop position of the traveling body is detected by measuring the excitation phase of the ground propulsion coil with respect to time, the composite magnetic flux of the AC magnetic flux detected by the sensor, and the on-board DC magnetic pole, or the AC magnetic flux of the propulsion coil, and detecting the phase difference. do. In order to more accurately detect the stop position according to the present invention, the following modifications can be considered.

(1} Increase the number of magnetic sensors.

■ The propulsion coil is excited one phase at a time, and the other phases are sequentially excited, and the position is detected based on the excited phase and the detection level of the magnetic sensor.

'3} The excitation of the propulsion coil is simultaneously excited by combining two or more phases, and the position is detected based on the excited phase and the level of the magnetic sensor.

'41 Excite the propulsion coil with alternating current (excitation may be performed using a combination such as ■ and '3' above), and detect from the phase difference between the current phase of the alternating current excitation of the propulsion coil and the induced voltage detected by the magnetic sensor. . According to the present invention, the stopping position of the traveling body can be detected without the need to provide a new device anywhere on the ground side in order to detect the stopping position of the traveling body.

[Brief explanation of drawings]

1 and 2 show different embodiments of the invention. 15... Traveling body, 16, 26... Magnetic sensor, 10-14... Ground propulsion coil, 17...
...Roadbed, 18...Field pole, 19...
Same magnetic flux. Figure 2

Claims (1)

[Claims] 1. In a linear synchronous motor consisting of a multiphase AC propulsion coil on the ground side and a field pole on the traveling body, a magnetic sensor installed on the traveling body near the ground propulsion coil and a device that excites the coil;
A stop position detection device for a linear motor, comprising: a device for detecting a vehicle position according to an output of the magnetic sensor that responds to a magnetic field generated by a propulsion coil.