JPS60141183A - Speed control system of plural motors - Google Patents

Abstract

PURPOSE:To effectively hold a line speed at a target value when varying a load torque by providing a low speed side priority circuit and a line speed regulator in a speed set signal line. CONSTITUTION:A motor 10 is controlled through a speed regulator 16 and a torque regulator 18, the speed of the motor 10 is detected by a speed detector 20, and the detected speed value is fed back to the regulator 16. A line speed regulator 34 is connected in parallel with a speed set signal supply line, the output signals of speed detectors 20, 20 provided in motors M1, M2 are connected with a low speed side priority circuit 36, and the output terminal of the circuit 36 is connected with the input terminal of the regulator 34.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a speed control method for controlling the line speed of multiple electric motors that are mechanically coupled or uncoupled depending on materials etc. to be constant in the general industrial field. It is.

[Prior art and its problems]

Conventionally, a large number of transfer means each having a drive roll and an idle roll arranged facing each other have been installed at a predetermined distance apart. It is being

In this type of transfer device, when material of a predetermined size is intermittently fed and transferred, the line speed of the electric motor that drives each drive unit becomes unstable due to load fluctuations.
In order to stably control the speed of a plurality of electric motors in order to keep the speed constant, various speed control methods have been proposed.

For example, as a conventional speed control method for multiple electric motors, the seventh
A circuit having the circuit configuration shown in the figure is known. That is, FIG. 1 shows a case where two transfer means each having a drive roll/co driven by an electric motor/Q and an idle roll l≠ are installed, and each electric motor M1. A speed regulator 16 that adjusts the speed based on a speed setting signal and a torque regulator 1 are connected to M2.

Further, a speed detector 20 is provided for each of the electric motors M+ and M2, and the speed detectors 20 are connected and arranged so that the detection value detected by the speed detector 2o is fed back to the speed regulator tA. Further, material detectors for detecting the material λ are provided adjacent to each of the drive rolls λ, and signals detected by these detectors 2 are supplied to the material tracking circuit 2. , both drive rolls/2,
/2 is configured to determine the state in which the material λ is caught. Therefore, when the material tracking circuit roller determines the tracking state of the material described above, the motor other than the speed reference motor (M+ in this case) (Mz in this case)
) is configured so that the motor speed has a droop characteristic by outputting an ON signal to the switch circuit 30 of the droop characteristic circuit λ♂ provided for the speed regulator/B. Therefore, with the conventional speed control method, the line speed can be controlled to be constant and the load balance can be stably maintained by the above-described configuration.

However, according to the conventional speed control method having the above configuration, in order to track the material, a switch circuit is required to connect and disconnect the material detector and the droop characteristic circuit, and tracking malfunctions. Therefore, there is a danger that load imbalance may lead to tripping due to overload. In addition, when material gets caught in both motors, one motor becomes subject to constant speed control and the other motor becomes subject to drooping characteristics, resulting in problems such as load imbalances except under specific load conditions. I'm worried.

In addition, as another speed control method, each of the speed regulators tl and /l of motors Mf and M2 configured as shown in Fig. 1 is configured to have drooping characteristics, so that the load is concentrated on one of the motors. A configuration that prevents this from occurring has also been proposed.

However, according to this type of speed control method, it is extremely difficult to maintain the line speed at a target value.

Therefore, in line speed control systems using multiple electric motors that repeatedly perform this type of mechanical coupling and uncoupling, the load balance is kept stable regardless of the mechanical coupling and non-coupling of materials. At the same time, it is required to be able to control the line speed to always maintain it at the target value.

[Purpose of the invention]

An object of the present invention is to achieve constant speed control of the line speed with a simple circuit configuration, and to maintain stable load balance at all times, and to achieve this at low cost through mechanical coupling and non-contact. A multi-motor speed control method with repeated coupling is provided.

[One point of the invention]

The speed control method for multiple electric motors according to the present invention provides a speed setting signal to each electric motor via a speed regulator and a torque regulator, and a speed detection signal detected via a speed detector provided in the electric motor. In a speed control system for multiple electric motors configured to perform speed control by feeding back to speed regulators, a droop characteristic circuit is connected to each speed regulator, and the line speed is connected to the speed setting signal supply line connected to these speed regulators. A regulator is connected, and a low-speed side priority circuit is provided which inputs the output value of the speed detector provided in each of the motors and is activated depending on the low-speed operation state of the motor, and the output signal of this low-speed side priority circuit is used as the line speed. The input to the regulator is configured to adjust the line speed.

That is, in the present invention, when a plurality of electric motors are mechanically coupled and uncoupled due to materials and the line speed fluctuates, the speed regulator is provided with drooping characteristics, and the low speed state of the electric motors is detected. By configuring the system to operate to maintain the line speed at a target value according to the load status of the motors, it is possible to control the speed of multiple motors by constantly controlling the line speed to a constant level and maintaining stable load balance. be done.

Therefore, in the speed control method of the present invention, the line speed regulator is operated according to the signal detected by the low-speed side priority circuit according to the load condition of each motor of the plurality of electric motors, and the line speed regulator It is preferable to configure the line speed to be maintained at a target value by adjusting the speed.

[Embodiments of the invention]

Next, an embodiment of the speed control method for multiple electric motors according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 is a circuit diagram showing an embodiment of the speed control method according to the present invention. For convenience of explanation, the same reference numerals are given to the same components in the conventional control circuit shown in FIG. 1, and detailed explanation thereof will be omitted. That is, in this embodiment, the electric motor 10 is controlled via the speed regulator tA and the torque regulator iz'41, and the speed detector 2
The present invention is the same as the conventional control circuit shown in FIG. 1 in that the speed of the electric motor 10 is detected by 0 and the detected speed value is fed back to the speed regulator 11. However, in this embodiment, the droop characteristic circuit -♂-4 is connected to the speed regulator /j of each motor M+, M2, respectively, and the speed setting value, - A line speed regulator 3 is connected in parallel to the number supply line, and the output signals of the speed detectors 〇 and 20 provided for each of the electric motors Ml and M2 are sent to the low speed side priority circuit 3.
t, and the output terminal of this low-speed side priority circuit 3B is connected to the input terminal of the lie/speed regulator 3≠.

Next, regarding the operation of the speed control circuit of this embodiment configured in this way, we will explain the operation explanatory diagrams of the materials shown in Figs. 3 to 5 and the operating waveform diagrams of the motor shown in Figs. This will be explained with reference to.

Now, considering the state where there is no material 22 between both drive rolls 12 and the idle roll/g, electric motor M+
, Mt all have the speed characteristics at point A1 shown in FIG. 7, and the speed setting values for electric motors M1 and M2 are values that compensate for no-load loss torque [speed command ■]. That is, the speed setting value in this case is determined by the speed setting signal and the line speed regulator 34! The value is the sum of the corrected outputs.

Next, as shown in FIG. 3, when the material 22 is caught between the drive roll saw driven by the electric motor MS and the idle roll llI, only the electric motor M1 moves to point B1 in FIG.
, and the speed decreases. This electric motor M1
The actual speed value is detected by the low-speed side priority circuit 3B, and is fed back to the line speed regulator 34', and by comparing the actual speed value of the motor M1 with the speed setting value, a speed command ■ is given to the motors M+ and M2. It will be done. That is, to explain this state based on FIG. 7, '11 motive M1 is at point B2.
The motor M2 shifts to the speed characteristic of point A2.

Furthermore, the material 22 is as shown in FIG.
If it is caught between the drive roll /2 and the idle roll /4 driven by the motors Ml and M2d, the load torque is shared between the electric motors Ml and M2d, and the speed characteristic shifts to point C1. As a result, the electric motor M+ detected by the low-speed side priority circuit 3t
, The line speed regulator J4A operates so that the speed of M2 matches the set value, and finally becomes the speed command ■.
The electric motors Ml and M2 shift to the speed characteristics at point C2.

Then, when the material 2.2 passes through the driving roll/2 driven by the electric motor M1 and reaches the state shown in FIG. Transition. Therefore, the load torque is applied only to the electric motor M2, and the electric motor M2 shifts to the speed characteristic at point B3. As a result, the actual speed value of the motor M2 is detected by the low-speed side priority circuit 3B, and is fed back to the line speed regulator 3G, and by comparing the actual speed value of the motor M2 with the speed setting value, the speed command M1. given to M2. That is, to explain this state based on FIG. 7, the electric motor M2 shifts to the speed characteristic of point B2, and the electric motor Ah
shifts to point-phantom velocity characteristics.

The material 2.2 then advances further and the motor M1. ．． M
Drive roll driven by 2/2. /2 disappears from 5-, motor M1. Both M2 have only no-load loss torque, and the speeds of the electric motors M1 and M2 shift to the speed characteristics at point A2. As a result, the motor M1. The line speed regulator 3≠ operates so that the speed of Ml matches the set value, and finally, when the speed command is given, the motors Mq and M2 shift to the speed characteristics at point A1.

In this way, according to the circuit of this embodiment, in the operating state where the load fluctuates as shown in FIG.
, Mz can maintain line speed at a set value while properly maintaining load balance in any case.

〔Effect of the invention〕

As is clear from the embodiments described above, according to the speed control method for a multi-electric WJ machine according to the present invention, a droop characteristic circuit is connected to the speed regulator of each electric motor and the speed adjustment is performed without providing a material detector. By providing a low-speed side priority circuit and a line speed regulator in the speed setting signal line connected to the speed setting signal line, the line speed can be reliably maintained even when the load torque fluctuates due to mechanical coupling or non-coupling of the motors depending on the material. It becomes possible to maintain the target value and also maintain stable load balance. Therefore, the speed control method of the present invention has a simpler configuration than conventional methods, and can stabilize the balance between line speed and load easily and at low cost.

Further, the speed control method according to the present invention can be applied to a motor of this type by having a computer retain the functions of some of the circuits (for example, a low speed priority circuit and a line speed regulator) that implement the method. It can be used as a versatile speed control device.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a control circuit diagram showing a conventional speed control method for multiple electric motors, FIG. 2 is a speed control circuit diagram showing an embodiment of the speed control method for multiple electric motors according to the present invention, and FIGS. 3 to S. is an explanatory diagram showing the state in which multiple electric motors are mechanically coupled or uncoupled by materials, Figure 7 is a waveform diagram showing the load torque sharing characteristics of multiple electric motors shown in Figure 1, and Figure 7 is a waveform diagram showing the load torque sharing characteristics of multiple electric motors shown in Figure 1. FIG. 3 is a waveform diagram showing speed control characteristics of the multiple electric motors shown in one figure. 10...Electric motor /J...Drive roll/≠...Idle roll /G...Speed regulator it...Torque regulator -〇...Speed detector λλ...Material 2hiro ...Material detector patent applicant Fuji Electric Manufacturing Co., Ltd.

Claims (1)

[Claims] (1) A speed setting signal is supplied to each motor via a speed regulator and a torque regulator, and a speed detection signal detected via a speed detector provided in the motor is fed back to the speed regulator to control the speed. In a speed control system for multiple electric motors configured to perform A low speed side priority circuit is provided which inputs the output value of a speed detector provided in the electric motor and operates depending on the low speed operating state of the electric motor, and an output signal of the low speed side priority circuit is inputted to the two-in speed regulator. A speed control method for multiple electric motors, characterized in that the line speed is adjusted by adjusting the line speed. (2. In the speed control method described in claim 7, the line speed regulator is actuated by the signal detected by the low-speed side priority circuit according to the load condition of each motor of the plurality of motors, and A speed control method for multiple electric motors configured to adjust the motor speed according to the load torque condition and maintain the line speed at a target value.