JPS58204798A - Power factor compensator at plural ac motor operation time - Google Patents

Abstract

PURPOSE:To reduce the power source capacity by driving a plurality of AC motors provided with a power factor compensating capacitor individually from the high frequency power source of a constant voltage and constant frequency, thereby enabling to compensate the power factor at acceleration time and operating time. CONSTITUTION:Many AC motors of reltively small capacity for driving a load having large inertia are operated in parallel by a high frequency power source, an AC motor 4 provided with a power factor compensating capacitor 8 is connected in parallel with a constant voltage and constant frequency power source 1. Accordingly, since the capacitor 8 is connected always to the motor 4, the power factor can be compensated for both accelerating time and rated operation time, the capacity of the power source can be reduced by reducing the supply power, and further since a variable voltage and variable frequency power source is not used for the power source 1, the structure can be simplified to improve the economy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for controlling a plurality of alternating current sources using one high frequency 'wL source.
This invention relates to a power factor compensator for parallel operation of electric motors.

Conventionally, when a single frequency power supply is used to operate a large number of relatively small AC motors in parallel to move a load with large inertia at high speed, and when performing power factor compensation, the power factor is compensated as shown in Figure 1. A sophisticated circuit system is used.

In FIG. 1, TYF substation voltage section frequency change 11JL power supply l light-2, hand switch, 3. ~3. A large number of drive AC motors 4. to 4. are connected in parallel, and a converter 6 is connected to #-2 via a switch 6.

When starting the AC motor 4, the frequency and voltage of the variable voltage 1iJI frequency dt source 1 are lowered to the rated frequency box pressure (/JIO%), and the hand opening/closing 31 to 3
．． Close and start. The frequency and voltage of the frequency power source 1 are constantly increased, and over a period of time, 5! : The rotational speed of the current motors 41 to 4 is completely increased. Then, variable voltage-J modulated wave'lL source 1 and AC motors 41 to 4. After confirming that it is suitable for the W class 1 shift, I close the switch 5, connect the condenser/+j6 to the trunk -2, and perform power factor compensation.

However, in this conventional circuit system, the lower At2/
) has many drawbacks.

In other words, when speeding up, 1=iJ variable voltage town variable frequency 'source 1
Since the output frequency of the power source 1 changes and power factor compensation cannot be performed, the output power of the variable voltage power source 1 becomes small, resulting in an increase in the RL source capacity, which is uneconomical.

Further, the switch 5 for opening and closing the power factor compensation converter 6 is required, and the wiring is complicated and the operation is complicated.

Furthermore, since a large amount of electric power (kb) and input electric power (L) constantly flows through the main line 2, it is necessary to increase the wiring capacity, which is disadvantageous from a social standpoint.

Furthermore, when a large number of '+1' spinning units are operated in parallel, the power factor compensation converter 6 is used as an intermediary all at once, so unnecessary troubles can be caused by connecting the malfunctioning machine to the hand switch 3. If disconnected at points 3 to 3, the capacitor capacity will be inappropriate, and this will have the disadvantage of impairing the economical operation of the variable voltage town variable frequency electric wire N1.

The object of the present invention is to eliminate the drawbacks of the prior art as described above,
The present invention provides a power factor compensator (1t) that can achieve the same economic efficiency, such as reducing source volume wrinkles and reducing the amount of wiring (1t) when multiple electric motors are operated.

In order to achieve this objective, the present invention uses a constant voltage constant frequency %tm as a high frequency power source, and a power factor f as a power factor compensator.
It is my special mission to make f8g4 into a ff-free service.

Hereinafter, the present invention will be explained with reference to FIG.

In FIG. 2, a constant voltage constant frequency 1JL source 7 is connected to a main line 2,
Hand switch 3. AC motors 41-4. are connected in parallel, and each 9:1 Jtt
Electric motor 4. ~4. Each of these is for n rate supplementary il tnf+j8I~8. are connected in parallel.

The constant voltage constant frequency voltage source 7 outputs the 5 o'clock rated pressure and the monastic frequency, and by turning on the hand switches 31 to 3, the AC motors 41 to 4. and the length of the power factor compensation converter connected in parallel with this motor 81 to 8. supplied to Therefore, the power factor compensation cono differential 8I~8
．． is light iIL, AC fIt motive 4. ~4. The speed increases to the short circuit speed.

According to one embodiment of the present invention, many effects can be obtained as shown in 'F'.

(1) A constant voltage constant frequency power supply is like a source of variable frequency power. -I&-pressure, gT! Rurudan is worried about Shuko's modesty,
The circuit configuration is reduced to half, which helps in making it smaller and lighter.

(2) The length of the power factor compensation converter is always strictly parallel to the main flow motor, so during acceleration and stationary operation, the joint power supply practice becomes aJ wear, and therefore Ia @ power supply - The force V reduction is tin, [# The capacity is reduced and it wakes up.

+1. ll) Since power factor supplementation is performed at m time, there is no small σl-flow in the main line, thus helping to reduce the current capacity of the main line. In particular, in the case of a multi-unit 1/J system, the large scale of the rIIL source equipment and AC motor will inevitably be long, so the 81" slope of the main trunk greatly increases the advantage in terms of construction.

(4) Since the power factor compensation cap/den length e-yu has been connected in parallel to the AC motor from the beginning, there is a special opening for the capacitor! The arrangement is simplified, which makes you feel at ease when you are worried, and it also helps improve your sexual performance.

(5) When operating multiple units, even if unnecessary AC motors or faulty current JI111I switches are turned off using a hand switch, 9: tAr, for power factor compensation, which is connected in parallel to the motor. Since the condenser length is also disconnected at the same time, the power factor compensation function 1 from the constant pressure constant frequency power supply side does not change, and the gap tJ'J of the constant voltage and constant frequency power supply remains unchanged. Useful for driving.

According to the present invention, according to the present invention, the swimming that has been congratulated above, [
Because of the jealousy of the heart, the relationship rL nature's direction, and the reduction of the N wiring equipment valley contribution, the same as the young fruit of the chastity and strategy of the profit. Gaana.

Figure + hl F, /) 1i11i Early connection Figure 1 Electrical circuit 1 of the power factor compensator in the past Wow.

2...# tighten, 3. ~31...Hand switch, 41~4
゜...AC motor, 7...Ya [pressure foot frequency denkaku, 8. ~
811 "゛Power Year Supplement 1 Sadagawa Ko/de/lj0 Agent Patent Attorney ＾Ka Akio; 'shi"7.゛・,′ 1st Seki-509-

Claims (1)

[Claims] 1. In a device that operates a plurality of AC motors connected in parallel with each other using a single V frequency source and performs deer rate compensation using a capacitor, a constant voltage constant frequency power source is used as the source of the frequency 11. and the power factor compensation condenser? A power factor compensator for operating a plurality of alternating current motors, the power factor compensating device being characterized in that each of the above-mentioned father flL motors is connected in parallel to the plurality of father flL motors.