JPS6359792A - Step-out detection for motor - Google Patents

Abstract

PURPOSE:To prevent a motor from stepping out, by providing an auxiliary winding besides an exciting main winding in a coil bobbin, and by detecting the induced voltage of this auxiliary winding. CONSTITUTION:An auxiliary winding 8 is provided besides an exciting main winding 7 in a coil bobbin 6. The induced voltage of the auxiliary winding 8 is detected when this exciting main winding 7 is electrified and excited. From the waveform it is detected whether there is any sign of step-out or actual step-out in the device. That is to say, if the lag or oscillation occurs to the rotating movement of a rotor 2 of a motor caused by the increase of the load, then the output voltage across the auxiliary winding 8 will be so irregularly disordered that both phase and waveform are deviated from the waveform in normal rotation. Thus, from the output waveform of the auxiliary winding, it can be detected that the occurence of step-out is drawing near.

Description

[Detailed Description of the Invention] Technical Field C] The present invention relates to a stepping motor, etc., which is provided with a plurality of excitation main windings and a rotor, and obtains torque from the rotor by sequentially driving the excitation main windings. This invention relates to a method for detecting step-out in a motor.

[Conventional technology]

As a motor, a rotor having a plurality of magnetic poles is supported in a stake having a plurality of excitation main windings, and torque is obtained from the rotor by driving the excitation main windings in a predetermined order. things are used.

A stepping motor is a typical example of this type.

In a stepping motor, the pole teeth of a stator having a plurality of excitation phases <mJ magnetic clay main windings are opposed to the magnetic poles of a rotor, and pulses are input to each excitation phase in a certain order, thereby rotating the rotor at a certain angle ( (step angle).

Therefore, the rotation angle of the rotor from its initial position is proportional to the number of input pulses, and the rotation speed is controlled by the frequency of the pulses (drive current switching speed of each excitation phase).

In addition, the driving method for this type of stepping motor is 1-1 phase excitation in which each excitation phase is excited one by one, 2-2 phase excitation in which two phases are simultaneously excited, or 1-phase excitation and 2-phase excitation are alternately performed. A type of 1-2 phase excitation that repeats 1-2 phases is adopted.

In this type of motor, when the load is excessive or the driving speed is abnormally high, the motor is likely to step out. That is, there is a lag between the timing of the rotor movement and the drive current, and the rotor movement is likely to be delayed or vibrate.

By the way, in conventional motors of this type, as a method for detecting the above-mentioned tax adjustment, a method such as attaching an encoder to the output shaft and constantly monitoring the position signal from the encoder has been adopted.

However, conventional motor step-out detection methods require special detection means such as encoders, making the structure complex and increasing costs. The problem was that it was impossible to prevent this.

〔the purpose〕

An object of the present invention is to provide a motor tax adjustment detection method that can solve the problems of the prior art and can prevent motor step-out with a simple configuration.

[Means to achieve the purpose]

The present invention achieves the above object by a method in which an auxiliary winding is provided in addition to the main excitation winding in a coil bobbin, and tax adjustment detection is performed by detecting the induced voltage of the auxiliary winding.

〔Example〕

The present invention will be specifically described below with reference to the drawings.

FIG. 1 shows the structure of a stepping motor suitable for carrying out the method of the present invention, and FIG. 2 shows the winding configuration of the motor of FIG.

In Fig. 1, a stator unit 1 constituting the case
A rotor 2 is rotatably supported within the rotor, and driving torque is extracted from a shaft (output shaft) 3 of the rotor.

The illustrated stator unit 1 is composed of a pair of stators 4.4 arranged adjacent to each other in the axial direction, and a winding 5 is housed inside each stator 4.

Each winding 5.5 is connected to an excitation main winding 7 (
It has a structure in which an auxiliary winding 8 (Fig. 2) is provided in addition to the main winding 8 (Fig. 2), and as shown in Fig. 1, from each stator 4.4 to the main winding lead 7A and the auxiliary winding lead. Line 8A is drawn out.

Furthermore, each stator 4 has an inner stator 9 and an outer stator 1.
The inner and outer stators are provided with inner stator poles 11 and outer stator balls 12 for forming magnetic flux paths.

On the other hand, each stator pole 1 is provided on the circumferential surface of the rotor 2.
1.12 are provided with magnetic poles facing each other with a predetermined gap.

FIG. 2 shows a winding configuration consisting of four excitation phases, and one stator 4 is provided with an excitation main winding forming the ■ phase and ■ phase and an auxiliary winding forming the A detection section. The other stator 4 is provided with an excitation main winding forming the ■ phase and ■ phase and an auxiliary winding forming the B detection section.

As a winding method for winding the auxiliary winding 8.8 into the coil bobbin 6, the following method can be adopted.

(i) When winding two wJ magnetic clay main windings 77 into one coil bobbin 6 at the same time, such as in a pie filer winding, three windings in addition to this are wound at the same time. How to obtain auxiliary winding by.

(ii) After winding the two excitation main windings 7.7,
A method of winding the auxiliary winding 8 several turns from above.

(iii) As shown in FIG. 3, the coil bobbin 6 is
A method in which the main winding bobbin chamber 13 and the auxiliary winding bobbin chamber 14 are provided separately, and the main winding 7.7 and the auxiliary winding 8 are wound in separate spaces.

As explained above, the motor step-out detection method according to the present invention uses a motor having a structure in which an auxiliary winding 8 is provided in addition to the main excitation winding 7 in the coil bobbin 6.
By detecting the induced voltage in the auxiliary winding 8 when energized and excited, the presence or absence of a sign of step-out or the presence or absence of step-out is detected from the waveform.

The step-out detection method will be specifically explained below.

When the main winding 7 is excited to rotate the motor (rotor 2), the output voltage from the auxiliary winding 8 during normal operation is as shown in FIG. That is, the waveform of the output voltage of the auxiliary winding 8 of both the A detection section and the B detection section in FIG. 2 has a regular sine waveform.

As the load on the motor increases, the motor is likely to step out, and signs appear. The induced output voltage from the auxiliary winding 8 at this time is as shown in FIG.

In other words, the increase in load causes delays and vibrations in the rotational movement of the motor rotor 2, and the output voltage from the auxiliary winding 8
As shown in the figure, it becomes irregularly disturbed, and both the phase and waveform become deviated from the waveform during normal rotation.

Therefore, when the output waveform from the auxiliary winding 8 is in the state shown in Figure 5, by detecting the phase or waveform (wave height) of the waveform, it is possible to detect that it is close to the tax adjustment. Tax adjustments can be avoided by taking measures such as increasing the motor drive current to increase the torque or reducing the drive speed based on the detection signal.

FIG. 6 is a block diagram of a control system for avoiding motor step-out based on the step-out detection method described above.

In FIG. 6, the operation of the motor 20 is controlled by operating a drive control circuit 21 based on a command signal and driving a drive circuit 22 with a signal from the drive control circuit.

When the motor 20 is driven, the induced output voltage waveform from the auxiliary winding 8 is guided to the phase level detection circuit 23 to detect phase shifts, wave height fluctuations, and the like.

This detection result is sent to the determination circuit 24 to determine whether or not synchronization has occurred or whether there is a sign thereof.

Depending on the judgment result of the judgment circuit 24, the drive circuit 22 is current-controlled to control the torque of the motor 20,
The motor 20 is controlled by timing control of the drive control circuit 21.
The rotational speed of the motor 20 is controlled, thereby avoiding step-out of the motor 20.

FIG. 7 is a flowchart showing the operating procedure of the control system of FIG. 6.

In FIG. 7, when the motor 20 is driven in step 100, the waveform of the induced output voltage from the auxiliary winding 8 of the motor is extracted in step 101, and the extracted waveform is compared with the normal waveform in step 102. and detects the presence or absence of a change in phase or wave height.

When a change occurs in the waveform, the process proceeds to step 103, where it is determined from the degree and state of the change whether there is a step-out or whether there is a precursor.

If there is a sign of step-out, the process proceeds to step 104 to increase the motor drive current by a predetermined amount to increase the torque, and further proceeds to step 105 to reduce the motor rotational speed by a predetermined amount to reduce the load.

After that, the process returns to step 101 and the above operations are repeated.

If there is no change in the phase or the like in step 102, the process returns to step 101 and the determination of the presence or absence of a change is repeated.

In step 103, if there is a change but it does not reach step-out, the state of the change is repeatedly checked.

According to the motor step-out detection method described above, the auxiliary winding 8 is wound in, and a sign of step-out is detected by software from the output waveform of the auxiliary winding, and tax adjustment is automatically avoided. With a simple configuration, it is now possible to easily and reliably prevent motor step-out.

In the illustrated embodiment, the auxiliary winding 8 is provided on each of the two (plural) stators 4, but the present invention can be carried out even if the auxiliary winding is provided on only one stator. .

In addition to stepping motors, the present invention can be similarly applied to any type of motor whose timing is controlled by pulse current, such as a synchronous motor.

〔effect〕

As is clear from the above description, according to the present invention, there is provided a motor step-out detection method that can easily and reliably prevent step-out with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a stepping motor suitable for implementing the method of the present invention, FIG. 2 is a schematic wiring diagram showing the winding configuration of the motor in FIG. 1, and FIG. 3 is a coil bobbin 1.
A schematic perspective view showing an example, Fig. 4 is the output waveform of the auxiliary winding during normal rotation, Fig. 5 is the output waveform of the auxiliary winding when the step-out approaches, and Fig. 6 is the implementation of the method of the present invention. FIG. 7 is a block diagram of a control system suitable for this purpose. FIG. 7 is a flowchart showing the operating procedure of the control system of FIG. ■−・−・−・・−Stator unit, 2・・−・−・
−・・−Rotor, 6−−−−−−−−−−Coil bobbin, 7−・・−−−− Main winding for excitation, 8−・・
−−−−−・Auxiliary winding, 20・・・・−・−・−Motor. Agent Patent Attorney Yasushi Ooto

Claims (1)

[Claims] (1) A method for detecting step-out of a motor, characterized in that an auxiliary winding is provided in the coil bobbin in addition to the main winding for excitation, and step-out detection is performed by detecting the induced voltage of the auxiliary winding.