JP2594620B2 - How to brake multiple motors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to, for example, a braking method for a plurality of electric motors used in a winder, and achieves both improvement of energy efficiency at the time of simultaneous stoppage and shortening of a stoppage time. It relates to an intended braking method for a plurality of electric motors.

(Prior Art) Conventionally, as a method of braking a winder, for example, a mechanical braking method is adopted in which a brake drum is mounted coaxially with a bobbin holder or a motor, and the brake drum is pressed against the shoe with a shoe to perform braking. However, with the recent increase in the size and speed of the winder, a large amount of inertia has to be braked, which causes abnormal noise between the shoe and the drum, rapid wear of the shoe, heating of the shoe, And so on.

Therefore, in order to solve such a disadvantage, in addition to the above-described mechanical braking method, an electric braking method of obtaining braking energy by consuming regenerative energy generated from a motor during braking may be used together. It has become

On the other hand, winders and the like use multiple motors,
It is often necessary to stop these motors simultaneously. In the case of such a simultaneous stop, the following two modes of braking using the electric braking method are described.
There are two things.

First Embodiment This is what is called “simultaneous simultaneous stop”. This is to stop the motor while gradually lowering the frequency supplied to multiple motors, collect regenerative energy generated from the motor during deceleration in one place, and consume it at once at the load. , All the motors are simultaneously braked.

Second mode This is what is called “time-divisional simultaneous simultaneous stop”. This is done by stopping the inverter one by one while lowering the frequency of the inverter little by little, and driving the other one with the regenerative energy from the motor during this deceleration, repeating this one by one and repeating the last one The regenerative energy from the motor is consumed by the load.

(Problems to be Solved by the Invention) However, the first embodiment described above has an advantage that the stop time is short because all the motors are simultaneously braked as shown in FIG. However, since the regenerative energy from all the motors is as large as the number of brakes, the load equipment (generally dissipated as heat by resistance) for consuming this regenerative energy becomes large, causing a problem in terms of equipment cost. In addition, since regenerative energy is simply radiated as heat, there is a problem in terms of effective use of energy.

On the other hand, in the above-described second embodiment, the regenerative energy is used as the drive energy of another motor, as shown in FIG. 5, so that the regenerative energy can be effectively used. In addition, the load capacity only needs to correspond to the regenerative energy of one motor that stops last, which has the advantage of reducing equipment costs, but requires a stop time for the number of driven motors. There is a problem that the stop time is extremely long.

(Object of the Invention) Therefore, the present invention sets an appropriate ratio between the number of braking-side motors and the number of driving-side motors driven by receiving regenerative energy from the braking-side motors, and sequentially sets the braking-side motors. By increasing the ratio of the number of vehicles, it is intended to reduce the stop time and reduce the size of the regenerative energy consuming equipment while effectively utilizing energy.

(Means for Solving the Problems) In order to achieve the above object, a method for controlling a plurality of electric motors according to the present invention is paired with each of a plurality of inverters having a common input side and driven by receiving power supply from the inverters. At the same time, at the time of braking, when simultaneously stopping a plurality of motors that transmit regenerative energy to the input side of the inverter, first, the number of brake-side motors and the number of drive-side motors are distributed at a predetermined ratio, and then the braking is sequentially performed. A method of braking a plurality of motors, wherein the ratio of the number of side motors is increased, wherein the predetermined ratio is based on a total amount of regenerative energy from the braking motor and a driving energy and balance required to drive the driving motor. It is configured to set.

(Operation) In the present invention, when simultaneously stopping a plurality of electric motors,
The number of brake-side motors and the number of drive-side motors driven by receiving regenerative energy from the brake-side motors are distributed at a predetermined ratio, and then the braking-side motors are sequentially reduced with the decrease in the regenerative energy of the brake-side motors. The number is increasing. Therefore, the regenerative energy during the braking period is effectively used as the drive energy, and the energy is significantly more effectively used as compared with the first embodiment.
The capacity of regenerative energy consuming equipment is small.

In addition, the number of motors on the braking side at the beginning of the simultaneous stop is a plurality of motors exceeding at least one, and the time required for stopping all the cures is reduced as compared with the above-described second embodiment.

In other words, energy can be effectively used, and the stop time can be reduced.

Hereinafter, the present invention will be described with reference to the drawings.

1 to 3 are views showing one embodiment of a winding machine to which the present invention is applied.

First, the configuration will be described. In FIG. 1, 1 is an AC /
The converter 1 is a DC conversion converter.
Convert AC 220 V to DC 300 V, and convert this DC 300 V to DC power supply P _DC
Is supplied on the power supply line L. The power supply line L is commonly connected to the input sides I _1N of the n inverters I _{1 to} In and also connected to the load resistance _RL via the switch 2 which is turned on by a command from the regenerative energy amount determiner SA. It is connected. The inverters I _{1 to} In vary the frequency of the AC power based on the operation command signals ON _{1 to} ONn including the frequency command value,
Output from the I _OUT, drives the n-number of the motor (electric motor) M ₁ to Mn This AC power f ₁ to fn. Inverter I ₁
-In, when stop signal OFF ₁ ~OFFn is input, the output frequency of the inverter I ₁ -In with decreasing little by little, I _1N regenerative energy from the motor M ₁ to Mn from I _OUT
And sends it out on the power line L. The motors M _{1 to} Mn are, for example, induction type AC motors.These motors M _{1 to} Mn receive supply of AC powers f _{1 to} fn from paired inverters I _{1 to} In, respectively, and have frequencies of f _{1 to} fn. To drive a bobbin for winding a yarn (not shown). Bobbin young rotational speed of the package wound on the bobbin (those formed with wound yarn) is detected by the n detectors RT ₁ ~RTn respectively, the rotational speed of each detected signal N ₁ ~Nn showing a is input to the control unit 3. Also, the simultaneous stop instruction signal STP from the simultaneous stop instruction switch 4 is input to the control unit 3 as necessary. The control unit 3 includes a speed control unit 3a and a regenerative control unit 3b, both of which are configured by, for example, a microcomputer. Speed control section 3a
Sets a target rotational speed of the optimum peripheral speed winding of yarn is obtained, determine the deviation between by comparing the N ₁ ~Nn and the target rotational speed from the detectors RT ₁ ~RTn, Based on this deviation,
A process of obtaining a frequency command value such that the rotation speeds of the motors vM _{1 to} Mn match the target rotation speed by, for example, PID (proportional, integral, differential) calculation and outputting the same included in the operation command signals ON _{1 to} ONn is performed. .

The regenerative control unit 3b executes the processing when the simultaneous stop instruction signal STP is input from the simultaneous stop instruction switch 4, and determines the ratio (to be described later) between the number of braking motors and the number of driving motors. Then, a motor to be the control side is designated, and the stop command signals OFF ₁ to OFF are supplied to the inverters I _{1 to} In for driving this motor (the one designated as the braking side).
Performs control for outputting OFFn, further, the regenerative energy amount during braking monitored from the value of N ₁ ~Nn, the regenerative energy amount is below a predetermined value, by adding determined brake-side electric motor, whereas Performs processing to output stop command signals OFF _{1 to} OFFn.

Here, the ratio between the number of brake-side motors and the number of drive-side motors is determined based on the following conditions, for example. In the following description, the rotation speeds and loads of all the motors are assumed to be the same for simplicity. The driving energy F required to drive the motor is represented by the following equation.

Where, W: output (WKw) n1: motor efficiency during driving ζ1: inverter efficiency during driving On the other hand, the maximum value E of regenerative energy E from the motor
_max is represented by the following equation.

E _max = W · n2 · ζ2 where n2: motor efficiency during regeneration ζ2: inverter efficiency during regeneration From the above equation, the number Y that can be driven by one vehicle's regenerative energy is calculated as: Y = n1 · ζ1・ N2ζ2 ... Y <1 is obtained. For example, n1 = n2 = 0.75, ζ
By substituting 1 = ζ2 = 0.95 into the above equation to find Y, Y = 0.75 ・ 0.95 ・ 0.75 ・ 0.95 Y ≒ 0.5 is obtained, indicating that 0.5 motors can be driven with one regenerative energy. It is. That is, the total amount of regenerative energy is determined from the number of braking-side motors, and the number of drive-side motors is a number that can be driven by this total amount of regenerative energy. If the value is known, an appropriate ratio can be easily obtained. Now, the total number of motors
When the number of motors on the braking side is 1 when Y = 0.5
The ratio may be set such that 0 units are designated and the remaining 5 units are designated as the number of driving motors. In this case, five units can be driven using the regenerative energy of ten units,
In other words, 10 vehicles can be braked using 5 vehicles as the braking load. Since the regenerative energy E is proportional to the square of the rotational speed as shown in the following equation, the regenerative energy also decreases as the rotational speed of the braking motor decreases. For this reason, the motor on the driving side is sequentially allocated to the braking side to compensate for the lack of regenerative energy, and eventually all of the driving side finally becomes the braking side.

However, GD ₂ : rotational energy due to inertia N: motor speed K: constant t: stop time Next, the operation will be described.

FIG. 2 is a flowchart of a process executed by the regeneration control unit 3b. First, to determine the presence or absence of simultaneous stop instruction signal STP from simultaneous stop instruction switch 4 at P _1, the case of Yes, the following processing is executed. If you have STP,
For example, it is assumed that the supply of the lubricating oil is cut off. However, in such a case, not all motors are operating and some motors may be stopped due to thread breakage or the like. Therefore, to confirm the motor number in fact operating in P ₂ (number of operating). As a confirmation method,
It is conceivable to receive a predetermined operating number notification signal from the speed control unit 3a.

In P _3, conditions for the proportion assay as described above (n1, n
2, .zeta.1, may be set in advance as a check and (system environment constant ?? 2)), then calculates the Y according to the previous formula in P _4, at P _5, the braking volume and a number of operating and Y to determine, to an inverter for driving the brake side of the motor with P _6, and outputs a stop command signal OFF ₁ ~OFFn. At this time, with respect to the speed control unit 3a, notification is made to prohibit the output of the operation command signal ON ₁ ~ONn to the inverter which drives the brake-side motor. In this way, when a predetermined number is designated as the braking side and another number is placed on the driving side as it is, regenerative energy from the braking side is transmitted to the power line L via the inverter, and the power line L To the drive side motor. That is, most of the drive energy of the drive motor is provided by regenerative energy, and efficient use of energy is achieved.

On the other hand, the P _7, monitors the rotation to N ₁ ~Nn braking side of the motor, from this rotation speed (using Equation) and calculates the regenerative energy, the regenerative energy decreases with decreasing rotational periodically, when it becomes less than the predetermined value P _8, P ₉
In determining the additional motor for distributing the drive side to the brake side, stop signal OFF ₁ for additional motor P ₁₀ ~OFF
Outputs n. Then, the P _11, the additional motor specified above P ₉ is checked whether it is the last motor, if NO instruction repeated after P _7, if YES instruction, the process ends I do.

As described above, in this embodiment, when simultaneously stopping a plurality of motors, first, the current number of operating motors is divided into the number of motors on the braking side and the number of motors on the driving side driven by the total amount of regenerative energy from the braking side. After that, the electric motor on the driving side is sequentially distributed to the braking side as the braking progresses.

Here, for an example in which a plurality of units are set to 15,
This will be described with reference to the characteristic diagram of FIG. In FIG. 3, the time t ₀ is the start time of the simultaneous stop, and the solid line (A) is a line indicating the time change of the regenerative energy due to the first number of braking motors (10 units) determined immediately after t ₀ , and a solid line (B). ) ~ (E)
Are the lines on the drive side immediately after t ₀ and indicate the time change of the regenerative energy per motor of each motor sequentially allocated to the braking side, and the bold solid line (f) indicates the time of the total regenerative energy during the stop period. The line indicating the change, that is, the thick solid line (f) is the sum of the energy amounts for each time of the solid lines (a) to (e). The dotted line (g) is a line indicating the drive energy required to drive the drive motor.

At time t ₀ , the regenerative energy for ten vehicles is equal to the drive energy for five vehicles. Therefore, regenerative braking is applied to 10 motors with 5 motors as the braking load.
The rotation speed is gradually reduced. Regenerative energy with decreasing rotational speed gradually decreases and when it is time t _1,
One (higher rotational speed) which was on the drive side until now is distributed to the braking side, and the added regenerative energy of the motor is added. That is, immediately after t _1, as a braking load to four, the regenerative braking is applied against the 11 units of the motor. Later, in t ₂ ~t _4, will be added sequentially each single increments, after all, at t _5, the motor should be additional driving side becomes 0 units. Since there is no motor serving as a braking load at t ₅ and later, the regenerative energy is applied to the resistive load RL is heat-consumed. Therefore, the capacity of the resistance load RL may be small enough to consume a small amount of regenerative energy remaining at the end, and the equipment cost can be reduced. Further, since the use regenerative energy during outage as driving energy, more efficient use of energy is achieved, the downtime required for simultaneously stopping, for example, a first period of t ₀ ~t _1, 10 cars Since the braking is performed at the same time, the stop time as a whole can be reduced (comparison with the above-described second embodiment).

(Effects) According to the present invention, the ratio between the number of braking-side motors and the number of driving-side motors driven by receiving regenerative energy from the braking-side motor is set appropriately, and the number of braking-side motors is sequentially reduced. Since the ratio is increased, regenerative energy can be used as driving energy, and energy can be effectively used. Further, the stop time can be reduced as compared with the above-described second aspect.

[Brief description of the drawings]

1 to 3 are views showing an embodiment of a winding machine to which a braking method for a plurality of electric motors according to the present invention is applied. FIG. 1 is an overall configuration diagram, and FIG. FIG. 3 is a characteristic diagram showing the relationship between the regeneration / drive energy and the stop time. 4 and 5 are views showing a conventional example, and FIG.
FIG. 5 is a characteristic diagram showing the relationship between the regenerative energy and the stop time according to the second embodiment, and FIG. 5 is a characteristic diagram showing the relationship between the regenerative energy and the stop time according to the second embodiment. L ...... power line, I ₁ -In ...... inverter, M ₁ to Mn ...... motor (electric motor), RT ₁ ~RTn ...... detector, 1 ...... converter, 3 ...... control unit, 4 ...... simultaneous stop Indication switch, Sa …… Regenerative energy amount judgment device.

Claims (1)

(57) [Claims] 1. A plurality of inverters, each of which is paired with each of a plurality of inverters having a common input side, is driven by receiving power supply from the inverters, and transmits regenerative energy to an input side of the inverter during braking. When simultaneously stopping the motors, first, after allocating a predetermined number of the number of braking-side motors and the number of driving-side motors, sequentially, a braking method of a plurality of motors that increases the ratio of the number of braking-side motors,
A method for braking a plurality of electric motors, wherein the predetermined ratio is set based on a balance between a total amount of regenerative energy from the braking electric motor and a driving energy required to drive the driving electric motor.