JP3364090B2 - Main inverter and auxiliary equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precharge device for a DC intermediate smoothing capacitor of a large capacity voltage type main inverter device, and an auxiliary device such as a controller for a cooling fan driving electric motor.

[0002]

BACKGROUND OF THE INVENTION Conventional apparatus will be described with reference to FIGS. 4 and 5.

[0003] As shown in FIG. 4, the high voltage input supply, switch 9 of the large capacitance of the high voltage, the buck transformer 2 and, via the main inverter device 24 of large capacity, connected to a main motor of large capacity, not shown Has been done.

The main inverter device 24 is the rectifier 2
1, a current limiting resistor 27, a bypass switch 28 that bypasses the current limiting resistor 27, a smoothing capacitor 22, and a main inverter (not shown).

Further, the low voltage input power source is connected to a cooling fan electric motor 7 for the main inverter device 24 via a switch 6.

As described above, when the switch 9 is turned on at the time of starting the main inverter device 24, the smoothing capacitor 22 is precharged from the high voltage input power source through the step-down transformer 2, the rectifier 21, and the current limiting resistor 27.

When the precharge is completed, the bypass switch 28 is turned on to bypass the current limiting resistor 27.
Then, the main inverter (not shown) starts up and starts the operation of the main motor (not shown) connected to the main inverter device 24. Further, the switch 6 is turned on, and the cooling fan electric motor 7 operates.

In this case, as shown in FIG. 5 , the voltage of the smoothing capacitor 22 changes exponentially, and the charging current gradually decreases with a large peak current flowing when the switch 9 is on.

Then, when the voltage of the smoothing capacitor 22 reaches the rated voltage, the precharge is completed.

[0010]

The above-mentioned conventional device has the following problems. (1) The conventional smoothing capacitor 22 is precharged by using a current limiting mechanism in which a current limiting resistor 27 is temporarily interposed between the rectifier 21 for the main motor and the smoothing capacitor 22. Since the current limiting resistor 27 having a too large resistance value cannot be adopted (if it is increased, the precharge time becomes long), a large peak current flows in the initial state where the smoothing capacitor 22 is not charged (see FIG. 5 ). .

Therefore, the current limiting resistor 27 should be adjusted to the peak current, and the bypass switch 28 should be purposely prepared to have a large capacity exceeding the rated current of the main motor, which is uneconomical. It was Further, since the voltage of the smoothing capacitor 22 rises exponentially, it took time to complete the precharge. (2) Since the power loss consumed by the current limiting resistor 27 is large (see FIG. 5 ), it is difficult to back up in an emergency with a small capacity power supply. Further, cooling against heat generation is also necessary. (3) The confirmation test of the main inverter and its control device can be performed only by electricity charged in the smoothing capacitor 22. The charging of the smoothing capacitor 22 with electricity is performed by turning on the main switch 9. However, in the unlikely event that there is a problem with the control device, main inverter, etc., a high voltage is connected and a large current may flow, resulting in a serious accident. (4) The cooling fan electric motor 7 employs a three-phase induction motor. However, since the rotation speed varies depending on the commercial power supply frequency, the fan and the cooling fan are provided according to the commercial power supply frequency so as to satisfy a predetermined cooling capacity. It is necessary to change the electric motor 7 for use. (5) Alternatively, when the cooling fan electric motor 7 or the like is used without change, it is operated at the maximum capacity regardless of the cooling capacity required by the large capacity main inverter device 24. Excessive consumption and shortened bearing life of the fan.

[0012]

The present invention takes the following means in order to solve the above problems .

(1 ) In an auxiliary device for a main inverter device having a smoothing capacitor and a cooling fan motor , a rectifier that can be connected to the smoothing capacitor, a step-up transformer connected to the rectifier, and another output terminal. Can be connected to the cooling fan electric motor and has one output end connected to the step-up transformer, an auxiliary machine inverter device connected to the changeover switch, and the smoothing capacitor to be charged with a constant current. A constant current controller for controlling the auxiliary inverter device, an auxiliary frequency controller for controlling the auxiliary inverter device to control the rotation speed of the cooling fan motor, and a changeover switch for controlling the changeover switch. An auxiliary device for a main inverter device, comprising: a controller.

[0014] In the above, during start-up, changeover switch by selector switch controller is coupled to the step-up transformer side.
Then, by the constant current controller, the predetermined increase
Inverter for auxiliary machine so that the current increases with increasing frequency
Control the device. Constant current from the auxiliary inverter device
The output is rectified by the rectifier through the step-up transformer, and the smoothing capacitor is precharged. In this way
Densa is a constant current without a large peak current flowing.
Be charged.

When the cooling fan motor is controlled after the precharge is completed, the changeover switch is first changed over to the other terminal side by the changeover switch controller.

[0016] Thereafter, auxiliary frequency controller calculates a required frequency control (switching) signal inverter device in accordance with the required cooling load, transmits the required frequency control signal to the auxiliary inverters. In the auxiliary inverter,
The required power is supplied to the cooling fan motor based on the required frequency control signal.

[0017] In this way, the cooling fan motor is rotating in accordance with the required frequency control signal from the auxiliary frequency controller
The number of turns is controlled. ( 2 ) The auxiliary device for the main inverter device according to (1 ) , wherein an AC reactor is interposed between the step-up transformer and the changeover switch.

In the above, the AC reactor suppresses an excessive peak of the input current from the auxiliary equipment inverter device 1 to the step-up transformer. ( 3 ) A main inverter device configured by a rectifier, a smoothing capacitor, and a main inverter to drive a main motor, a main frequency controller that controls the main inverter, a rectifier that supplies a charging current to the smoothing capacitor, and a rectifier. A connected step-up transformer, a cooling fan electric motor for cooling the main inverter device, a changeover switch having one output end connected to the step-up transformer and the other output end connected to the cooling fan electric motor, An auxiliary inverter device connected to the changeover switch, a constant current controller for controlling the auxiliary inverter device to charge the smoothing capacitor with a constant current before starting the main motor, and the main motor According to the operation, the cooling fan motor
And auxiliary frequency controller for controlling the inverter device for the auxiliary machine to control the rotational speed, the main inverter and the auxiliary, characterized by comprising and a change-over switch controller for controlling the change-over switch apparatus.

In the above, after the precharge is completed, the main frequency controller outputs an alternating current according to the target rotation speed and voltage of the main motor, so the control signal of the main inverter is calculated and sent to the main inverter. The main inverter operates in response to this control signal.

Others are almost the same as the above ( 1 ). ( 4 ) The main inverter device and the auxiliary device according to ( 3 ), wherein an AC reactor is interposed between the step-up transformer and the changeover switch.

The above operation is the same as the above ( 2 ).

[0022]

Figure 1 implementation form of the embodiment of the present invention, FIG. 2, will be described with reference to FIG.

As shown in FIG. 1, the high voltage input power, the main switch 9, via the main inverter device 24 for buck transformer 2 and a mass, which is connected to the main motor 25 of a large capacity. The main inverter device 24 includes a rectifier 21, a smoothing capacitor 22, a main inverter 23, and a smoothing capacitor 2.
It is composed of a voltmeter 26 for detecting the voltage of 2.

[0024] In addition, the low voltage input power supply, auxiliary switch 1
Through 0 are tangent <br/> is continued in the inverter device 1 of the voltage-type small capacity. The auxiliary machine inverter device 1 includes a rectifier, a smoothing capacitor, and an auxiliary machine inverter.

As shown in FIG . 1, an inverter device for auxiliary machinery
1 is inserted between the AC reactor 3 and the AC reactor 3.
Has been. Then, one output end a of the changeover switch 8 is an AC
It is connected to the reactor 3, and is sent to the smoothing capacitor 22 of the main inverter device 24 through the boosting transformer 4 for charging and the rectifier 5 for charging in order , and the other output end b is cooled.
It is connected to the electric fan motor 7. For auxiliary equipment
The inverter device 1 is also used for the cooling fan electric motor 7.
An auxiliary frequency controller 33 is provided for this purpose.

The AC reactor 3 is installed in order to prevent the output current peak of the inverter device 1 for a voltage type auxiliary device from becoming excessive.
When utilizing the leakage reactance between the secondary winding and the secondary winding, the AC reactor 3 may be omitted.

The control device is composed of the main control device 30a and auxiliary equipment.
Main control device 30.
a is a main frequency control for controlling the main inverter device 24.
Switch 31 for controlling the switch 31 and the main switch 9
Is built in. On the other hand, in the auxiliary device control device 30b,
Constant current controller 3 for controlling the auxiliary inverter device 1
2, control the frequency controller 33 for accessories and the accessory switch 10
Control the auxiliary equipment switch controller 36 and the changeover switch 8.
A control switch controller 35 is incorporated. Na
In Fig. 1, the lines between the controllers are not connections,
The flow of control is shown.

The constant current controller 32 considers various constants of the AC reactor 3, the charging step-up transformer 4, the charging rectifier 5 and the like so that the charging current becomes constant and the voltage per unit time. The increase amount, that is, the frequency increase amount is programmed in advance. Then, when the control by the constant current controller 32 is started, the frequency is controlled so as to increase at a constant value over time, and the voltage increases at a constant value accordingly.

The inverter is controlled by a PWM (Pulse Width Modulation) system which produces a plurality of pulsed outputs during an AC half cycle to control the magnitude of the voltage. It is controlled to be constant.

[0030] Incidentally, the invention is not limited thereto, for example, an ammeter is provided to the rectifier 5 for charging, a measurement signal of the current meter as feeds back signal, the frequency and voltage at a constant value over time You may control so that it may increase.

The main frequency controller 31 calculates a control (switching) signal of the main inverter 23 according to the target rotation speed and voltage of the main motor 25, and the main inverter device 24.
This control signal is transmitted to.

[0032] In the main inverter 24, the power input from the buck transformer 2, rectifier at the rectifier 21 and the smoothing capacitor 22 after being smoothed by the main inverter 23, a control signal from the main frequency controller 31 Based on this , the necessary electric power is supplied to the main motor 25. In this way, the main motor 25 is controlled at the target rotation speed.

The main switch controller 34 controls ON / OFF of the main switch 9.

In the above-mentioned structure, when starting the main motor 25, first, it is confirmed that all the switches 9 and 10 are off. Further, in the above configuration, the main motor 2
Regarding the precharge before the start of No. 5, the changeover switch 8
To the one output end a side by the changeover switch controller 35.
Replace it.

Next, the accessory switch controller 36 turns on the accessory switch 10.

When the auxiliary device switch 10 is turned on, the constant current controller 32 calculates a control (switching) signal of the auxiliary device inverter device 1 in order to charge the smoothing capacitor 22 with a constant current, and the auxiliary device inverter is operated. This control signal is transmitted to the device 1. The auxiliary inverter device 1 supplies the required power to the smoothing capacitor 22 via the AC reactor 3 based on this control signal. In this way, the smoothing capacitor 22 is precharged.

In this case, as shown in FIG. 2, the output frequency and voltage of the auxiliary inverter device 1 are controlled to increase, and the voltage of the smoothing capacitor 22 increases in proportion to time. In this case, the charging current flowing through the auxiliary device inverter device 1, the step-up transformer 4, and the rectifier 5 is maintained at a constant value.

On the other hand, a voltmeter 26 for detecting the voltage of the smoothing capacitor 22 is connected to the main inverter device 24,
And it determines whether the voltage of the smoothing capacitor 22 has reached the target voltage, the control by a constant current controller 32 at the time when the target voltage we were ends, precharge is completed.

However, the present invention is not limited to this, and the determination may be made based on the frequency and the working time.

In this case, as shown in FIG. 2, there is no loss due to the current limiting resistance in the conventional example, only a slight loss of the step-up transformer 4, the rectifier 5, etc. It is held down.

When the precharge is completed, the cooling fan is
When controlling the fan motor 7, first the changeover switch 8
Switch to one terminal b side by switch controller 35, then
The main frequency controller 31 controls the main inverter device 24 to start the activation of the main motor 25.

After that, in the auxiliary equipment frequency controller 33,
The cooling target signal from the wave number controller 31 (of the main inverter 23
Frequency signal, current signal of main inverter 23, main inverter
Output signal of the controller 23 or the measured temperature of the main inverter 23, etc.
Depends on this cooling target signal)
Frequency control of the inverter device 1 for auxiliary equipment (switch
Signal) to calculate the auxiliary signal of the inverter device 1 for the auxiliary device.
This required frequency control signal is transmitted to the inverter. Auxiliary equipment
The inverter is based on this required frequency control signal.
The necessary electric power is supplied to the fan motor 7.

In this way, the cooling fan electric motor 7 is
It is controlled according to the cooling target signal from the main frequency controller 31.
Be done.

As described above, the precharge of the smoothing capacitor 22 is carried out under the condition of constant current and low loss, so that the equipment cost can be reduced. It is possible to reduce the total power and the maximum power required for precharge, as the low voltage input power, can be used emergency power supply device or the like, it is easy to pre-charge.

When conducting a confirmation test of the main inverter device 24 and its control device, the smoothing capacitor 22 is charged by the charging device connected to the above-mentioned low voltage input power source, and only this charged small amount of power is consumed. Since the confirmation test can be performed in step 1, there is no possibility of causing a serious accident, and the confirmation test can be safely performed many times without turning on / off the high-voltage large-capacity main switch 9.

The charging voltage is not limited to 100%,
For example, it may be 50 percent.

Further, in the conventional one, the current limiting resistor 27
The bypass switch 28 and the bypass switch 28 are provided for high voltage and have the same current capacity as that of the main motor 25, and occupy a considerable space. However, since these are unnecessary, space can be saved. .

Next, the operation and starting the respective devices in Fig. 3
More will be described.

First, before starting the main motor 25 (main
Switch 9 before turning on the switch 9 and the auxiliary switch.
Check that the switch 10 is off (stepS
1).

The main frequency controller 31 sends a start preparation command signal for the main motor 25 to the auxiliary switch controller 36.
It is received at (step S2 ).

The accessory switch controller 36 receives the start preparation command signal, turns on the accessory switch 10 by the accessory switch controller 36 (step S3), and at the same time, switches the selector switch 8 via the selector switch controller 35. To the precharge side (one terminal a side) (step S4).

In order to charge the smoothing capacitor 22 with a constant current (constant voltage increase rate, constant frequency increase rate),
Control signal from the constant current controller 32 to the inverter device 1 transmits a (switching signal of the inverter) (step S5).

[0053] In this way, the inverter device 1
The output from is sequentially sent to the smoothing capacitor 22 through the AC reactor 3, the charging step-up transformer 4, and the charging rectifier 5. As a result, the smoothing capacitor 22 is precharged at a constant charging current, a constant voltage increase rate, and a constant frequency increase rate as shown in FIG. 2 (step S6).

On the other hand, a voltmeter 26 for detecting the voltage of the smoothing capacitor 22 is connected to the main inverter device 24, and the voltage of the smoothing capacitor 22 is a target (or rating).
And reaches said Taka whether the stamp constant voltage (step S7), and Setsu換Ru precharge is completed (the step S8), and changeover switch 8 by the switching switch controller 35 to the other output terminal b side (Step S10).

In parallel with this, a signal for precharge completion is transmitted from the constant current controller 32 to the main frequency controller 31, and then the main switch controller 34 turns on the main switch 9 (step S9).

In this way, the preparation for starting the main motor 25 is completed (step S11).

When the start preparation is completed, the main frequency controller 3
The frequency control signal of the main electric motor 25 is transmitted from 1 to the main inverter device 24 (step S12). Then, the main inverter device 24 drives the main motor 25 (step S
13).

In parallel with this, the frequency controller 33 for auxiliary machinery
Then, receiving the cooling target signal from the main frequency controller 31,
Calculates the frequency and voltage according to the cooling target signal, and
It calculates a use control of the inverter device 1 (switching) signal, and transmits the control signal to the inverter device 1 (step S14).

[0059] In the inverter device 1, and supplies the necessary power to the cooling fan motor 7 based on the control signal. In this way, the cooling fan electric motor 7 is controlled at the target frequency (step S15).

[0060] Note that those described above, the case to be carried out on all the changes automatically between each step, it is not limited thereto, carried out all across the controllers, or part manually You may do it.

The controllers 31, 32, 33, 34,
For 35 and 36 of the built form, it is not limited thereto, for example, the main frequency control vessel 31 is embedded in the main inverter 24, switching the constant current controller 32 and the auxiliary frequency controller 33 Switch controller 35 and auxiliary equipment
The main switch controller 34 and the auxiliary device switch controller 36 may be incorporated into another power supply device while being incorporated into the inverter device 1 for use .

Further, the rectifier 5, the step-up transformer 4, the auxiliary inverter device 1, and the constant current controller 32 are integrated into an auxiliary unit (further, the changeover switch 8, the changeover switch controller 35, the constant current controller). 32 is also added), and it is also possible to add this auxiliary unit to the existing main inverter device.

[0063] Also, in the implementation described above, the switch and the disconnecting switch, fuse, fused disconnector, contactor, circuit breaker, is a general term, such as a vacuum circuit breaker, as appropriate selected to Depending on the application place It will be installed. Further, as the changeover switch, a changeover type switch having three output terminals, a switch having two switches arranged in parallel, or the like can be used.

As described above, the precharge of the smoothing capacitor 22 is carried out under the condition of constant current and low loss, so that the equipment cost can be reduced. Since the total power or the maximum power required for precharging can be reduced, a small-capacity low-voltage power supply or an emergency power supply device can be used as the input power supply, which facilitates precharging.

Since the cooling fan electric motor 7 is independent of the commercial power supply condition, the design of the cooling fan and the cooling fan electric motor 7 can be standardized. In addition, electric motor 7 for cooling fan
Since it rotates according to the required cooling capacity, energy can be saved and the life of the bearing can be extended.

[0066] Furthermore, since shared to both precharge and cooling one inverter device 1, it can be reduced in equipment cost.

[0067]

As described above, the present invention has the following effects. (1) Since the precharging of the smoothing capacitor of the main inverter device can be carried out under the condition of constant current and low loss, the facility cost can be reduced. (2) The total power and maximum power required for precharging can be reduced, and precharging from an emergency power supply device or the like becomes easy. (3) Since cooling is not driven by a commercial power source as in the conventional case, standardization of cooling fan design can be achieved. (4) motor cooling fan since the rotation speed control in accordance with the required cooling capacity, thereby the life of the energy saving and bearing. (5) When conducting a confirmation test of the main inverter device and its control device, it is possible to charge the smoothing capacitor with the above-mentioned charging device and perform the confirmation test with only a small amount of this charged electric power, so it is a major accident. In addition to eliminating the possibility of reaching, it is possible to safely perform confirmation tests many times without turning on / off a high-voltage, large-capacity main switch. (6) In the conventional type, the current limiting resistor and the bypass switch are provided for high voltage and occupy a considerable space, but these are unnecessary,
Space saving can be achieved.

[Brief description of drawings]

1 is a configuration diagram of the implementation of the embodiment of the present invention.

2 is a view illustrating the operation of the embodiment shown in FIG.

FIG. 3 is a processing flowchart of the embodiment shown in FIG.

FIG. 4 is a configuration system diagram of a conventional example.

FIG. 5 is an explanatory view of the operation of the conventional example shown in FIG.

[Explanation of symbols]

1 Auxiliary inverter device 2 Step-down transformer 3 AC reactor 4 Charging step-up transformer 5 Charging rectifier 6 Switch 7 Cooling fan motor 8 Changeover switch 9 Main switch 10 Auxiliary switch 21 Rectifier 22 Smoothing capacitor 23 Main inverter 24 Main Inverter 25 Main motor 26 Voltmeter 27 Current limiting resistor 28 Bypass switch 30a Main controller 30b Auxiliary controller 31 Main frequency controller 32 Constant current controller 33 Auxiliary frequency controller 34 Main switch controller 35 Switching Switch controller 36 Auxiliary equipment switch controller

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02P 5/408-5/412 H02P 7/628-7/632 H02P 21/00 H02M 7/42-7 / 98 H02P 5/46-5/52 H02P 7/67-7/80

Claims (4)

(57) [Claims] What is claimed is: 1. A smoothing capacitor and the cooling fan motor
In accessory device for the main inverter having a rectifier which can be connected to the smoothing capacitor, first output terminal with a step-up transformer connected to said rectifier, the other output terminal may be connected to the motor for the cooling fan Is a changeover switch connected to the step-up transformer, an auxiliary machine inverter device connected to the changeover switch, a constant current controller for controlling the auxiliary machine inverter device to charge the smoothing capacitor with a constant current, An auxiliary machine frequency controller for controlling the auxiliary machine inverter device to control the rotation speed of the cooling fan electric motor, and a changeover switch controller for controlling the changeover switch. Auxiliary equipment for inverter equipment. Wherein between the step-up transformer and the changeover switch, accessory devices for the main inverter apparatus according to claim 1, characterized in that interposed an AC reactor. 3. A main inverter device comprising a rectifier, a smoothing capacitor and a main inverter for driving a main motor, a main frequency controller for controlling the main inverter, a rectifier for supplying a charging current to the smoothing capacitor, and A step-up transformer connected to the rectifier, a cooling fan electric motor for cooling the main inverter device, and a changeover switch having one output end connected to the step-up transformer and the other output end connected to the cooling fan electric motor. An auxiliary device inverter device connected to the changeover switch, a constant current controller for controlling the auxiliary device inverter device to charge the smoothing capacitor with a constant current before starting the main motor, and the main device auxiliary frequency for controlling the inverter device for the auxiliary machine to control the rotational speed of the electric motor for the cooling fan in accordance with the operation of the motor A main inverter device and an auxiliary device comprising a controller and a selector switch controller for controlling the selector switch. 4. The main inverter device and the auxiliary device according to claim 3 , wherein an AC reactor is provided between the step-up transformer and the changeover switch.