JPS6237085A - Setting method of zero position of synchronous motor with position detector - Google Patents

Abstract

PURPOSE:To align the zero points of a synchronous motor and a position detector precisely by measuring the reference position of the synchronous motor obtained from induced voltage and the zero position of the position detector independently. CONSTITUTION:A synchronous motor 2 is driven by a driving section 11 for adjustment, and the induced voltage Eu of the synchronous motor 2 is measured by a reference-position deciding section 13. On the other hand, output voltage V0 from a position detector 1 is measured by a zero-position detecting section 14. The angle of deviation thetae between the zero point of induced voltage Eu and the zero point of output voltage V0 is detected. A coupling 15 is removed, the shaft of the position detector 1 is turned, and the angle of deviation thetae is brought to zero. Accordingly, the zero points of the synchronous motor and the position detector can be aligned accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method for setting the zero position of a synchronous motor with a position detector when the synchronous motor and the position detector are installed so that their zero positions coincide.

(Technical Background of the Invention and Problems thereof) A synchronous motor used in a positioning system for a machine tool or the like is usually equipped with a position detector to detect its accurate position. In particular, in order to control the absolute position with high precision, it is necessary that the reference position, that is, the zero position of the synchronous motor, and the zero position of the position detector match with high precision.

Conventionally, as a method for aligning and attaching the zero position, there is a method that utilizes a servo loop configured through a synchronous motor, a one-position detector, and a servo amplifier. This principle is based on the principle that when a low torque is applied to the synchronous motor in a state where the servo loop is close to a follow-up state, the state where the current of the synchronous motor is the lowest indicates the reference position of the synchronous motor.

This example will be explained with reference to FIGS. 5 and 6. FIG. 5 is a block diagram showing an example of the configuration of a servo loop, in which rotation command 6 to rotation command 01 of synchronous motor 2 is transmitted to servo amplifier 8.
When the rotation command 01 is input, the servo amplifier 8 receives this rotation command 01.
The buffer amplifier 9 outputs an output according to the difference between the position and the signal Oo.
The synchronous motor 2 is driven by the voltage obtained by power amplifying the power in the buffer amplifier 9. This synchronous motor 2 and the rotating shaft of the position detector 1 are mechanically attached, and this position detector! rotates to the specified position,
When the device signal Oo constituted by the position detector 1 and the rotation command θl issued from the rotation command 6 match, the synchronous motor 2 stops.

Figure i6 is a configuration diagram for explaining the method of adjusting the zero position of the synchronous motor 2 and position detector l using the above-described servo system. It mechanically serves as a fitting/unrotating part, and a spring clamp 4 is further attached to the shaft of the synchronous motor 2 via a lever 3, so that a constant torque can be applied to the shaft of the synchronous motor 2. The zero position setting device 5 is electrically connected to the synchronous motor 2 and the zero position detector 1. To explain its operation, first, when the synchronous motor 2 is stopped, That is, while the servo system is following, external torque is applied to the synchronous motor 2 by the spring clamp 4 via the lever 3. At this time, the shafts of the synchronous motor 2 and the position detector l are uncoupled, the shaft of the position detector l is turned so that the motor current of the synchronous motor 2 is minimized, and when the motor current is the minimum, the synchronous motor 2. Fit the shaft of the position detector l. In this way, the synchronous motor 2
However, with this method, it is difficult to accurately align the zero points of the synchronous motor 2 and the position detector 1, making it difficult to achieve optimal control in the positioning system. There were some problems, such as:

(Object of the invention) This invention was made under the above circumstances,
SUMMARY OF THE INVENTION An object of the present invention is to provide a method for setting a zero position of a synchronous motor with a position detector, which enables accurate zero point alignment of the synchronous motor and position detector.

(Summary of the Invention) The present invention relates to a method for setting a zero position of a synchronous motor with position detection in which a position detector is attached to the synchronous motor. By independently measuring the reference position of the synchronous motor obtained from the voltage and the zero position of the detector, the position detector is adjusted to the synchronous motor so that the reference position and the zero position coincide. It is designed so that it can be installed.

(Summary of the Invention) FIG. 1 is a block diagram showing the principle of the present invention, in which a synchronous motor 2 and a position detector 1 are attached to each other by a coupling 15 in such a manner that their respective shafts can be inserted and removed. Furthermore,
The synchronous motor 2 is driven by an adjustment drive section 11. The total 11111ik12 is composed of a reference position determining section 13 and a zero position detecting section 14, each of which is connected to the excitation line of the synchronous motor 2 and the output line of the position detector l. The zero position detecting section 14 is capable of measuring the reference position of the position detector 2, and the zero position of the position detector l.

The operation of such a configuration will be explained with reference to the operation analysis diagram of FIG.

In FIG. 2, the horizontal axis θ shows the mechanical rotation angle of the synchronous motor 2 and the position detector l, and the vertical axis shows the voltage. It shows the induced voltage Eu of the synchronous motor 2 when it rotates, and here it is three-phase U, V.

It shows the voltage of the U phase. And curve L3
is the position detector l, where the output voltage VO of the resolver is shown, and the zero point of the induced voltage Eu and the zero point of the output voltage VO are at an angle θ
It shows that there is a deviation by e. This means that the reference position when the U phase of the synchronous motor 2 is used as a reference and the zero position of the position detector l are deviated by an angle θe. That is, by measuring the reference position of the synchronous motor 2 and the zero point of the position detector 1 independently, the deviation angle Oe can be found.

Therefore, if the deviation angle θe becomes zero by removing the coupling 15 and rotating only the shaft of the position detector 1, that is, if the curve L2 is obtained, then the reference position of the synchronous motor 2 and the position detector This means that the zero position of l matches.

Here, the induced voltage Eu of the synchronous motor 2 is based on the U-phase voltage, but the same effect can be obtained even if the V-phase or W-phase is used as a reference. In addition, here we will explain the case where the number of poles of the synchronous motor 2 is 2, and accordingly, the resolver of the position detector 1 was also used with a shaft angle multiplier of 1x. Only one cycle of the generated voltage within is shown. Therefore, if the number of poles of the synchronous motor 2 is 4, there will be two cycles of voltage within one rotation, and if it is 2N poles, there will be N cycles of voltage. If the resolver used in accordance with this number of poles has a shaft angle multiplier of N×, the resolution can be increased accordingly.

FIGS. 3(A) and 3(B) show an embodiment of the adjustment drive unit 11, and FIG. 3(A) shows an example in which the handle is connected to the shaft of the synchronous motor 2 to be rotated manually. (B) shows that the motor 16 is connected to the synchronous motor 2.
The synchronous motor 2 is attached to the shaft of the synchronous motor 2 via a coupling 17, and the synchronous motor 2 is rotated by controlling the motor 16.

Figure 4 shows an example of how to install the synchronous motor 2 and the detector 1.A rough reference point and zero point are clearly marked on each shaft using a keyway, etc. is the virtual origin, couplings 15A and 1
5B connects the synchronous motor 2 and the shafts 22 and 2 of the position detector l.
1 to each other.Next, as mentioned above, once the deviation angle Oe has been determined, remove this coupling and finely adjust the mounting angle of the detector so that the deviation angle θe becomes zero. can.

Although the synchronous motor 2 and the position detector l are attached here using a coupling, the present invention can be similarly applied to a built-in type in which the detector l is attached directly to the synchronous motor 2.

Here, the measuring instrument 12 can be used not only to set the above-mentioned zero position but also to determine a failure. That is, when the synchronous motor 2 or the position detector fails, this measuring device 1
If the reference point of the synchronous motor 2 and the zero point of the position detector l do not match, there is an electrical failure in the synchronous motor 2 or the position detector l, or the coupling 15 is Failure analysis can be performed to determine whether a failure has occurred.

(Effects of the Invention) As described above, according to the method for setting the zero position of a synchronous motor with position detection according to the present invention, the reference position t of the synchronous motor and the zero position of the position detector can be detected and mounted with high precision. Therefore, it is possible to perform optimal control in a positioning system, etc., and the output loss of the synchronous motor can be reduced, which has the advantage that the synchronous motor can be controlled with high performance.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining the invention in detail,
FIG. 2 is a voltage waveform diagram explaining the present invention in detail, FIGS. 3(A), (B), and 4 are diagrams showing an embodiment of the apparatus for realizing the present invention, and FIGS. Each figure shows an example of the conventional technology. l...Position detector, 2...Synchronous motor, 3...Lever, 4...Spring hook, 5...Zero position setting device,
6... Rotation command, 8... Servo amplifier, 9... Buffer amplifier, lO... Handle, 11... Adjustment drive section, 12... Total 0 trial, 13... Reference position Judgment unit, 14... Zero position detection unit, 15.15A, 15B...
・Coupling, 16...Motor, 21.22...
shaft.

Claims (1)

[Claims] In a method for setting a zero position of a synchronous motor with a position detector in which a position detector is attached to the synchronous motor, the reference position of the synchronous motor is obtained from an induced voltage induced by rotating the synchronous motor by an external drive source. and,
By independently measuring the zero position of the position detector, the position detector can be attached to the synchronous motor so that the reference position and the zero position match. A method for setting the zero position of a synchronous motor with a position detector.