JP2004260939A - Control device for winding-type motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a control device for a winding-type motor improved in connection and high in withstand voltage by using a semiconductor as a switch means used at the secondary side of the winding-type motor. <P>SOLUTION: The control device for the winding-type motor comprises resistors 4, 5 and 6 connected to phases at the secondary side of the three-phase winding-type motor each having a plurality of taps; semiconductor switch means 12 to 16 that are composed of semiconductor elements each of which is arranged at each tap of the resistor of each phase, which turns on a short circuit between the taps between the phases, and are back-to-back connected to one another; and a means 18 that accelerates the three-phase winding-type motor by gradually reducing the resistance of each resistor by sequentially turning on the semiconductor switch means. The control device is also characterized in that the semiconductor switch means 12 at the tap of a first stage, which is firstly turned on when accelerating the motor in common at each phase, is connected in series to each of the semiconductor switch means 13 to 16 of the taps on and after a second stage. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for a winding type motor used for hoisting driving of a crane, and more particularly to a control device for a winding type motor in which the secondary side control of the winding type motor is made semiconductor and maintenance-free.
[0002]
[Prior art]
A conventional winding motor control device will be described with reference to FIG. In FIG. 5, primary terminals R1, S1, and T1 are connected to a three-phase AC power supply, and one end of a normally open contact 2, 3 for operation is connected to the terminals R1, S1, and T1. The other ends of the open contacts 2 and 3 are connected to the primary side of the three-phase wound motor 1.
[0003]
On the secondary side of the three-phase winding type electric motor 1, secondary terminals u2, v2, w2 are provided, and the resistors 4, 5, 6 are connected to the secondary terminals u2, v2, w2 in a star connection. It is connected. The normally open contacts 7, 8, 9, 10, and 11 are connected to the taps Ta11 to Ta15, Ta21 to Ta25, and Ta31 to Ta35 of the resistors 4, 5, and 6, respectively, so as to be openable and closable.
[0004]
The operation of the control device for the wound motor configured as described above will be described with reference to the configuration diagram of FIG. 5 and the timing chart of FIG. Before the start of operation, all the normally open contacts 2, 3, 7, 8, 9, 10, and 11 are open, and when an operation command is given by the controller 17, it is processed by the control unit 18 to generate the control command. Can be The normally open contact 2 is closed by the control command, the three-phase AC power is applied to the primary side of the wound motor 1, and the resistors 4, 5 and 6 are connected to the secondary side of the wound motor 1. Start slowly from the state. The normally open contacts 7, 8, 9, 10, and 11 are sequentially closed by sequentially giving an acceleration command by the controller 17, and the resistance values of the resistors 4, 5, and 6 are gradually reduced to reduce the resistance of the wound motor 1. The rotation speed is gradually increased to perform high-speed operation (see FIG. 7).
[0005]
The control unit 18 also includes a time limit circuit, and can set a minimum time limit required when the normally open contacts 7 to 11 are sequentially closed. Even if the controller 17 is operated to close the normally open contacts 7 to 11 at a stretch, the normally open contact 7 is closed after the time T1 after the normally open contact 2 is closed. After the normally open contact 7 is closed, the normally open contact 8 is closed after time T2, and the normally open contact 9 is closed after time T3. After the normally open contact 9 is closed, the normally open contact 10 is closed after time T4, and the normally open contact 11 is closed after time T5.
[0006]
Eventually, when the acceleration command from the controller 17 is gradually released, the normally open contacts 11, 10, 9, 8, and 7 are opened in this order, and finally, the operation command of the wound motor 1 is turned off. The contact 2 is opened, and after a time T6, the normally open contact 3 for reverse rotation is closed to perform reverse-phase braking. When the speed is reduced, the power supply is shut off by opening the normally open contact 3 for reverse rotation, and the motor 1 is stopped while restraining the wound motor 1 by a mechanical brake (not shown).
[0007]
However, the control device for the wound motor 1 configured as described above must frequently maintain the contacts that open and close the current by turning on and off the normally open contacts 2, 3, 7, 8, 9, 10, and 11. I had to.
[0008]
In recent years, in order to eliminate the above-mentioned maintenance, instead of the normally open contacts 7, 8, 9, 10, and 11, semiconductor elements are connected in anti-parallel and used.
[0009]
FIG. 6 shows a configuration using a semiconductor element, and FIG. 8 shows a timing chart thereof. FIG. 6 is a diagram in which the normally open contacts 7, 8, 9, 10, and 11 of FIG. 5 are replaced with switching units 12, 13, 14, 15, and 16 as semiconductor switch means in which semiconductor elements are connected in anti-parallel. The short-circuit command to the normally-open contacts 7, 8, 9, 10, 11 is converted into a switching command by the control unit 18, and after the normally-open contact 2 is closed, the switching units 12, 13, 14, 15 after time T1 to T5. , 16 are sequentially turned on to close the circuit, and the resistance values of the resistors 4, 5, and 6 are gradually reduced to gradually increase the rotation speed of the wound motor 1 to perform high-speed operation. As described above, the operation of the conventional configuration shown in FIG. 6 is basically the same as that of FIG.
[0010]
Control of the wound-type motor of FIG. 5 configured as described above closes the normally connected contacts 7, 8, 9, 10, and 11 of the resistor connected to the secondary side in order, and connects the resistors 4, 5,. 6, the resistance value of the winding motor 6 is gradually reduced, and the rotation speed of the winding motor 1 is gradually increased to achieve high-speed operation. Electromagnetic contactors have been mainly used for the normally open contacts 7, 8, 9, 10, and 11. Since the magnetic contactor is a contact, an electric arc is generated when the contact changes from the closed state to the open state, and the electric contact gradually melts and scatters due to the electric arc, so regular maintenance and inspection must be performed. In order to solve this problem, switching units 12, 13, 14, 15 each comprising a semiconductor switch instead of an electromagnetic contactor which is a contact in the control of the wound motor configured as shown in FIG. , 16. Thyristors are mainly used for semiconductor switch means.
[0011]
In the method of decelerating and stopping the wound motor, on the secondary side of the motor in the case where the normally open contact 3 for reverse rotation is closed after time T6 after all the normally open contacts are released and reverse phase braking for electrically braking is performed. The generated voltage will be described. When the winding motor 1 is operated at a value close to the slip S = 0 at 100% speed, the secondary voltage is almost E ₂ = 0 [V]. And the secondary voltage becomes the maximum voltage 2E ₂ [V] as shown in FIG.
[0012]
In addition, there is a configuration in which a portion of a switching unit composed of semiconductor switch means is constituted by rectification means and switch means for turning on and off the output side of the rectification means (for example, see Patent Document 1).
[0013]
[Patent Document 1]
JP 2000-23478 A
[Problems to be solved by the invention]
Conventionally, in a control device for a large-capacity wound-type motor, the secondary side has a relatively high voltage, and there has been a problem that a semiconductor element such as an inexpensive thyristor having a low reverse withstand voltage cannot be used for a large-capacity wound-type motor. Further, there is a problem that a semiconductor element having a high withstand voltage is very expensive and is not suitable for controlling a wound-type motor requiring versatility.
[0015]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a control device for a wound-type motor in which a semiconductor element such as a thyristor having a low reverse withstand voltage can be used in a secondary circuit of the wound-type motor. With the goal.
[0016]
[Means for Solving the Problems]
In view of the above object, the present invention provides a resistor connected to each phase on the secondary side of a three-phase winding type motor and having a plurality of taps, and for turning on and off a short circuit between taps for each phase. A semiconductor switch means composed of semiconductor elements connected in anti-parallel and provided for each tap of a resistor of each phase, and these semiconductor switch means are sequentially turned on to gradually reduce the resistance value of each resistor to form a three-phase resistor. Means for accelerating the wound motor, wherein the semiconductor switch means of the first stage tap which is turned on first during acceleration for each phase is connected in series with the semiconductor switch means of the second and subsequent taps, respectively. A control device for a wire-wound electric motor, characterized in that:
[0017]
Further, a resistor connected to each phase on the secondary side of the three-phase winding type motor and having a plurality of taps, and a resistor of each phase for turning on and off a short circuit between the taps of each phase. Semiconductor switch means provided for each tap and comprising semiconductor elements connected in anti-parallel with each other; and means for sequentially turning on these semiconductor switch means to gradually reduce the resistance value of each resistor to accelerate the three-phase winding type motor Wherein the semiconductor switch means of the first tap which is turned on first at the time of acceleration for each phase is connected in series with the semiconductor switch means of the second and subsequent taps, respectively. In the control device of the winding type electric motor.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described according to embodiments.
Embodiment 1 FIG.
FIG. 1 is a connection diagram of a control device for a wound motor according to an embodiment of the present invention. In the figure, portions denoted by the same reference numerals as those of the prior art indicate the same or corresponding portions. In FIG. 1, in the control device of the winding type electric motor, resistors 4, 5, 6 are connected to secondary terminals u2, v2, w2 of the three-phase winding type electric motor 1 by star connection.
[0019]
Between the taps Ta11, Ta21, Ta31 of the resistors 4, 5, 6 and the neutral point, a switching unit 12 including a semiconductor switch means for each phase, which is an opening / closing means in which a thyristor (semiconductor element) is connected in anti-parallel. (First stage) is connected. The taps Ta12, Ta22, and Ta32 of the resistors 4, 5, and 6 are similarly connected to one end of a switching unit 13 (second stage) including semiconductor switch means for each phase, and the other end is connected to the switching unit 12. It is connected. As a result, the switching unit 12 and the switching unit 13 are connected in series, and the voltage can be divided.
[0020]
Similarly, the taps Ta13, Ta23, and Ta33 of the resistors 4, 5, and 6 are connected to one end of the switching unit 14 (third stage) having the same structure, and the taps Ta14 and Ta24 of the resistors 4, 5, and 6 are connected. , Ta34 are connected to one end of the switching unit 15 (fourth stage), and the taps Ta15, Ta25, Ta35 of the resistors 4, 5, and 6 are connected to one end of the switching unit 16 (fifth stage). The other ends of the switching units 13 to 16 are collectively connected for each phase and connected to the switching unit 12 so that they are connected in series and can be divided.
[0021]
The operation of the control device for the wound motor configured as described above will be described with reference to the timing charts of FIGS. Before the start of operation, the normally open contact 2 is open, the switching units 12, 13, 14, 15, and 16 are off, and when an operation command is given by the controller 17, The open contact 2 is closed, and the three-phase AC power is applied to the primary side of the wound motor 1. The wound motor 1 starts slowly from a state in which the resistors 4, 5, and 6 are connected to the secondary side.
[0022]
When an acceleration command is sequentially input by the controller 17, a switching command to each semiconductor (switching unit) is output from the control unit 18, and the switching unit 12 is turned on after a time T1. Next, after a time T2, the switching unit 13 is turned on. At this point, the switching units 12 and 13 are connected in series. Further, after the time T3, the switching unit 14 turns on, and the switching units 12 and 14 are connected in series. Further, after the time T4, the switching unit 15 is turned on, the switching units 12 and 15 are connected in series, and after the time T5, the switching unit 16 is turned on, and the switching units 12 and 16 are connected in series. Thus, the second and subsequent stages are configured so that two switching units are always connected in series.
[0023]
As described above, after the times T1 to T5, the switching units 12, 13, 14, 15, and 16 are sequentially turned on, and the taps of the resistors 4, 5, and 6 connected to the secondary side are short-circuited. Is decreased (gradually decreased) to increase the rotation speed of the wound motor 1. Eventually, when the acceleration command from the controller 17 is gradually released, the switching units 16, 15, 14, 13, and 12 are turned off in this order. The contact 2 is opened, and after a time T6, the normally open contact 3 for reverse rotation is closed to perform reverse-phase braking. When the speed decreases, the power is shut off by opening the normally open contact 3 for reverse rotation, the mechanical brake power is shut off, and the wound motor 1 is stopped while being restrained by the mechanical brake (not shown).
[0024]
Here, a method of decelerating and stopping the wound motor will be described. The command from the controller 17 is gradually released, and when the operation command of the wound motor 1 is finally turned off, the power is shut off by opening the normally open contact 2 and the mechanical brake (not shown) is used. There are a means for stopping the wound motor 1 while restraining it, and a means for using the reverse phase braking and the mechanical brake together.
[0025]
When the operation command from the controller 17 is turned off to the winding type electric motor 1 during operation, the semiconductor switch means of all the switching units are turned off, and after the normally open contact 2 is opened, after the time T6, That is, the normally open contact 3 for reverse rotation is closed to electrically apply braking. For example, when the winding type electric motor 1 is operated at a value close to the slip S = 0 at 100% speed, the secondary voltage is also almost E ₂ = 0 [V]. Is S = 2, and the secondary voltage is 2E ₂ [V] (maximum voltage) as shown in FIG. Further, since the switching unit is a semiconductor switch means, there is a limit in withstand voltage. This generated voltage is a voltage of rated secondary voltage (E ₂ ) × 2 × √2 times (peak value), and this voltage is applied to the semiconductor switch means.
[0026]
However, the switching units 13, 14, 15, and 16 are connected in series with the switching unit 12, and a voltage of the rated secondary voltage (E ₂ ) × 2 × √2 times (peak value) is applied by two semiconductor switch means. Partial pressure becomes possible.
[0027]
Embodiment 2 FIG.
FIG. 2 is a connection diagram of a control device for a wound motor according to another embodiment of the present invention. In the figure, portions denoted by the same reference numerals as those of the above-described embodiment indicate the same or corresponding portions. In FIG. 2, the control device of the wound motor is such that resistors 4, 5, and 6 are star-connected to the secondary terminals u2, v2, and w2 of the three-phase wound motor 1 via switching units 111, 121, and 131. I have. Each of the switching units 111, 121 and 131 is provided with a plurality of semiconductor switch means.
[0028]
A switching unit 111 is used for short-circuiting each tap of the resistor 4. Semiconductor switch means 111a is connected between the taps Ta10 and Ta11. Semiconductor switch means 111b, 111c, 111d and 111e are connected between the taps Ta11 and Ta12, Ta13, Ta14 and Ta15, respectively.
[0029]
The switching unit 121 is used for short-circuiting each tap of the resistor 5. Semiconductor switch means 121a is connected between the taps Ta20 and Ta21. Semiconductor switch means 121b, 121c, 121d, and 121e are connected between the tap Ta21 and Ta22, Ta23, Ta24, and Ta25, respectively.
[0030]
The switching unit 131 is used for short-circuiting each tap of the resistor 6. Semiconductor switch means 131a is connected between the taps Ta30 and Ta31. Semiconductor switch means 131b, 131c, 131d and 131e are connected between the taps Ta31 and Ta32, Ta33, Ta34 and Ta35, respectively.
[0031]
First-stage semiconductor switch units 111a, 121a, 131a, second-stage semiconductor switch units 111b, 121b, 131b, third-stage semiconductor switch units 111c, 121c, 131c, fourth-stage semiconductor switch units 111d, 121d, The semiconductor switch means 111e, 121e, 131e in the fifth stage 131d are turned on and off at the same timing by the switching command of the control unit 18.
[0032]
The operation of the control device for the wound motor configured as described above will be described with reference to the timing charts of FIGS. Before the start of operation, the normally open contact 2 is open, all the semiconductor switch means are off, and when an operation command is given by the controller 17, the normally open contact 2 is closed via the control unit 18. Then, the three-phase AC power is applied to the primary side of the wound motor 1. The motor starts slowly from a state in which the resistors 4, 5, and 6 are connected to the secondary side of the wound motor 1.
[0033]
When an acceleration command is sequentially input by the controller 17, a switching command to each semiconductor is output from the control unit 18, and the semiconductor switch units 111a, 121a, 131a are turned on after a time T1. Next, after a time T2, the semiconductor switch units 111b, 121b, and 131b are turned on. At this point, the semiconductor switch means 111a and 111b, 121a and 121b, and 131a and 131b are connected in series, respectively. Further, after the time T3, the semiconductor switch units 111c, 121c, and 131c are turned on, and the semiconductor switch units 111a and 111c, 121a and 121c, and 131a and 131c are connected in series.
[0034]
Further, after the time T4, the semiconductor switch means 111d, 121d, and 131d are turned on, the semiconductor switch means 111a and 111d, 121a and 121d, and 131a and 131d are respectively connected in series. After the time T5, the semiconductor switch means 111e, 121e, and 131e are turned on. The semiconductor switch means 111a and 111e, 121a and 121e, and 131a and 131e are connected in series. In this manner, the second and subsequent stages are configured so that two semiconductor switch means are always connected in series.
[0035]
The operation of the control device of the wound-type motor configured as described above is a summary of the configuration of the first embodiment for each phase, and the order of switching and the means for dividing the secondary voltage of the wound-type motor are as follows. This is the same as the first embodiment.
[0036]
【The invention's effect】
As described above, in the winding motor control apparatus according to the present invention, each resistor connected to each phase on the secondary side of the three-phase winding motor, semiconductor switch means including a plurality of semiconductor elements, and the semiconductor switch Control means for sequentially turning on the means, and performing an irregular series connection (the first stage is used for the second and subsequent series connection) when the semiconductor switch means performs star connection between the phases. The voltage applied to the element can be divided. As a result, a semiconductor element such as a thyristor having a low reverse withstand voltage can be used in the secondary circuit of the wound motor. In addition, even a large-capacity three-phase winding motor having a high secondary voltage can be easily controlled, and contact point maintenance is almost unnecessary.
[0037]
Further, in the control device for the wound motor according to another embodiment of the present invention, the semiconductor switch means is connected in series between the respective phases in the above embodiment, but the first stage is replaced by two stages for each phase. The voltage applied to the semiconductor element can be divided by using it for serial connection after the first element.
[Brief description of the drawings]
FIG. 1 is a connection diagram showing a control device for a wire-wound electric motor according to Embodiment 1 of the present invention.
FIG. 2 is a connection diagram showing a control device for a wire-wound electric motor according to Embodiment 2 of the present invention.
FIG. 3 is a timing chart showing the operation of the first embodiment of the present invention.
FIG. 4 is a timing chart showing an operation of the second embodiment of the present invention.
FIG. 5 is a connection diagram showing a conventional control device for a wound motor.
FIG. 6 is a connection diagram showing another conventional control device for a wound-type electric motor.
FIG. 7 is a timing chart showing the operation of the control device for the wound motor of FIG. 5;
FIG. 8 is a timing chart showing the operation of the control device for the wound motor of FIG. 6;
FIG. 9 is a diagram showing a secondary voltage for slip.
[Explanation of symbols]
1 three-phase wound motor, 2, 3, 7, 8, 9, 10, 11 normally open contacts (switching means), 4, 5, 6 resistors, 12, 13, 14, 15, 16, 111, 121, 131 switching unit, 17 controller, 18 control unit, 111a, 111b, 111c, 111d, 111e, 121a, 121b, 121c, 121d, 121e, 131a, 131b, 131c, 131d, 131e Semiconductor switch means.

Claims (2)

A resistor connected to each phase on the secondary side of the three-phase winding motor and having a plurality of taps,
Semiconductor switch means comprising a semiconductor element connected in anti-parallel and provided for each tap of a resistor of each phase, for turning on and off a short circuit between taps for each phase,
Means for sequentially turning on these semiconductor switch means to gradually reduce the resistance value of each resistor to accelerate the three-phase winding type motor;
With
The semiconductor switch means of the first stage tap which is turned on first during acceleration for each phase is connected in series with the semiconductor switch means of the second and subsequent taps, respectively. Control device. A resistor connected to each phase on the secondary side of the three-phase winding motor and having a plurality of taps,
Semiconductor switch means comprising a semiconductor element connected in anti-parallel and provided for each tap of a resistor of each phase, for turning on and off a short circuit between taps of each phase,
Means for sequentially turning on these semiconductor switch means to gradually reduce the resistance value of each resistor to accelerate the three-phase winding type motor;
With
A first-stage tap semiconductor switch means which is first turned on at the time of acceleration for each phase is connected in series with a second-stage or later tap semiconductor switch means, respectively; Control device.

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