JPS63186581A - Driver for induction motor - Google Patents

Abstract

PURPOSE:To rise a speed pattern corresponding to a preset driving position of an induction motor and to abruptly stop the motor by controlling an inverter according to the speed pattern. CONSTITUTION:A tachometer generator 4 which detects the rotation of the output shaft of an induction motor 2 to output an electric signal corresponding to a rotating speed as a feedback signal, and an encoder 5 which detects the rotating amount of the output shaft of the motor 2 to output a pulselike electric signal are provided, and the output signals of the generator 4 and the encoder 5 are input to an output pattern controller 6 for controlling an inverter 1. A position/speed pattern setter 7 is connected to the controller 6. When the inverter 1 inputs a correction control signal from the controller 6, it corrects the frequency of a driving power to the motor 2 so as to control the motor 2 to a set speed, and corrects a driving power to hold a predetermined output torque.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a drive device for controlling the drive of a general-purpose induction motor using an inverter method. The present invention relates to an induction motor drive device that can perform variable speed control.

(Prior art) Conventionally, when a general-purpose induction motor is driven by an inverter, variable speed control is generally performed by patterning only the frequency change of the electric power supplied from the inverter to the induction motor. It was done.

(Problems to be Solved by the Invention) According to the conventional general-purpose induction motor drive method described above, variable speed control of the induction motor is performed by changing only the frequency of the drive power output from the inverter. Therefore, if the required torque of the load was large, the acceleration time would be less than I%, or the rated output torque could not be maintained. Furthermore, since it was difficult to control the drive position of the induction motor, there was a problem in that it could not be used for loads that required precise position control.

Therefore, in the present invention, an inverter that can change the output power and frequency is used to drive the induction motor, and the drive power output from the inverter to the induction motor and its frequency correspond to a preset drive position. The technical problem is to solve the above-mentioned conventional problems by controlling the vehicle based on the speed pattern of the vehicle.

(Means for solving the problem) The technical means for solving the above problem is that it is possible to arbitrarily change the drive 8 power and the frequency that is supplied to the induction motor by the drive 8 device of the induction motor. an inverter, a motor speed detection means for detecting the speed of the induction motor and outputting a signal corresponding to the detected speed, and a motor speed detecting means for detecting the drive of the induction motor and outputting a signal corresponding to the detected drive i4. Motor drive 111
It has a detecting means and a means for arbitrarily setting a speed pattern corresponding to the driving position of the induction motor, and the rotational state of the induction motor is recognized by inputting a signal output from the motor speed detecting means. , the drive position of the induction motor is recognized by inputting the signal output from the motor drive amount detection means, and the control signal for driving the induction motor according to the set speed pattern is input to the drive position of the induction motor. The present invention is to provide a configuration including drive control means for outputting to an inverter.

(Action of the invention) According to the induction motor drive device having the above configuration,
After a speed pattern corresponding to the drive position of the induction motor is set, when the inverter outputs drive power to drive the induction motor, the drive control means inputs a signal from the motor speed detection means. The acceleration state of the induction motor is recognized, and the drive position of the induction motor is recognized by inputting a signal from the motor drive control means. The drive control means that recognizes the acceleration state and drive position brings the induction motor into an acceleration state based on the set speed pattern,
The speed deviation is calculated and a control signal for correcting the speed deviation is output to the inverter. The inverter receiving this control signal corrects the driving power and frequency of the induction motor, and drives the induction motor according to the set speed pattern.

(Example) Next, one embodiment of the present invention will be described with reference to the drawings.

In Fig. 1, a 3-phase power source is input, and after being converted to a DC power source via a rectifier 1A, this DC power source is converted to variable frequency drive fII power using a pulse width modulation control method, for example, and outputted using PWM output control. The inverter section 1 is provided with a built-in frequency conversion cover turn generator IC that outputs a frequency corresponding signal and a drive #J power corresponding signal to the PWM output control section 1B. Connect induction motor 2. Note that the induction motor 2 is set to a rated voltage of 172, which is the output voltage of the inverter section 1, for example, to enable the induction motor 2 to start up for a short time.

Furthermore, a drive mechanism for a moving truck, for example, is connected to the output shaft of the induction motor 2 as a load 3.

On the other hand, a tacho generator 4 detects the rotation of the output shaft of the induction motor 2 and outputs an electric signal corresponding to the rotation speed as a feedback signal, and a tacho generator 4 detects the rotation amount of the output shaft of the induction motor 2 and rotates m( An encoder 5 is provided that outputs a pulsed electrical signal corresponding to the amount of drive.

The output signals of the tachogenerator 4 and encoder 5 are as follows:
The signal is input to an output turn control section 6 for controlling the inverter section 1. The output turn control section 6 is equipped with a digital calculation and control function using, for example, a microcomputer as a central function, and controls the rotational speed and drive of the induction motor 2 based on the electrical signals output from the tacho generator 4 and encoder 5. Manage quantity. Note that a position-velocity pattern setting section 7 is connected to the output pattern control section 6 . This position-velocity pattern setting section 7 includes, for example, a keyboard (not shown) and a setting display device,
When the induction motor 2 drives the load 3, that is, the moving carriage, the running position and running speed of the moving carriage are set in a pattern. For example, a deceleration position or a stop position is set, and the running position , the travel speed corresponding to the deceleration position, the stop position, etc. are set in a pattern. This position-velocity setting pattern is transferred as an electrical signal to the output turn control section 6 and stored therein.

The output turn control unit 6 digitally calculates the actual rotational speed and drive of the induction motor 2 based on the electric signals output from the tachogenerator 4 and encoder 5 as described above, and also sets the position-speed pattern. By converting the position-velocity pattern set in section 7 into the output shaft rotation pattern of induction motor 2, the speed deviation between the actual and set speed is calculated, and a correction control signal for converging the deviation to zero is sent to inverter section 1. Output to.

When the inverter section 1 receives the correction control signal from the output control section 6, the inverter section 1 corrects the frequency of the driving power for the induction motor 2 in order to control the induction motor 2 to the set speed, and maintains the required output torque. In order to achieve this, the drive 1j power is also corrected. Therefore, the movable cart travels, decelerates, and stops according to the position-speed pattern set by the position-speed pattern setting section 7.

FIG. 2 shows a position-velocity pattern of a movable trolley or the like, that is, a moving characteristic of the movable trolley, comparing the present embodiment with the conventional technique. In the conventional technology, the load was driven by controlling only the output power frequency of the inverter, and the output torque was not controlled by l and Q.
As shown in the figure, it was necessary to prevent the low F of the stopping accuracy by increasing the acceleration time or by increasing the low speed time after deceleration. On the other hand, in this embodiment, since both the output power and the frequency of the induction motor 2 are controlled, it is possible to secure the required output torque along with variable speed control, and the speed is increased as shown in FIG. It is possible to perform short-term acceleration, deceleration without requiring a low-speed period, or rapid stop according to the set pattern.

According to the above embodiment, the load 3 can be positioned by inputting the signal from the encoder 5, and smooth positioning can be performed by inputting the feedback signal from the tacho generator 4.

Although the above embodiment shows an example of a three-phase motor, it can also be applied to a single-phase motor by changing the phase control of the inverter section 1 and the output cover turn control section 6. Further, when the induction motor 2 is replaced with a synchronous motor, it can be used as a simple AC servo motor. In addition, when driving a capacitor running type induction motor instead of the induction motor 2, the frequency conversion cover turn generator I of the inverter section 1 is used.
By changing the output of C and controlling the phase shift by 90 degrees, it is possible to eliminate the need for a running capacitor.

Note that when stopping the load 3 at a fixed position, a constant stopping torque must be ensured by applying direct current to the induction motor 2 or automatically switching the direction of the output current between forward and reverse. Can be done.

(Effects of the Invention) As described above, according to the present invention, the drive power output from the inverter to the induction motor and its frequency can be varied based on a speed pattern corresponding to a preset drive position. The effect is that the required torque can be output from the induction motor, and it is possible to start up in a short time and control the speed of the fish to stop, so that it can be used for loads that require precise stopping accuracy and quick start-up. There is. Furthermore, since an inexpensive general-purpose motor can be used, the control system can be constructed at low cost.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram comparing the control characteristics of the embodiment of the present invention and the prior art. 1... Inverter section 2... Induction motor 3... Load 4... Tacho generator 5... Encoder 6... Output turn control section 7... Position-speed pattern setting section Applicant Stock Company Star Seiki Applicant Thai Tetsuri Co., Ltd. Agent
Patent attorney Hidehiko Okada (3 others) Figure 2 (no drawings)

Claims (1)

[Claims] an inverter capable of arbitrarily changing the drive power and frequency supplied to the induction motor; a motor speed detection means for detecting the speed of the induction motor and outputting a signal corresponding to the detected speed; motor drive amount detection means for detecting the drive amount of the induction motor and outputting a signal corresponding to the detected drive amount; and means for arbitrarily setting a speed pattern corresponding to the drive position of the induction motor; inputting the signal output from the detection means to recognize the rotational state of the induction motor; inputting the signal output from the motor drive amount detection means to recognize the driving position of the induction motor; An induction motor drive device comprising: drive control means for outputting a control signal to the inverter for driving the induction motor according to the set speed pattern.