JP2000134997A - Frequency converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a frequency converter which can control the rotational speed of an induction motor, using the induction motor small in outside dimension. SOLUTION: This is a frequency converter in which the rotor of a first induction motor 3 and the rotor of a second induction motor 6 are coupled with each other, and primary winding 4 and primary winding 7 are connected to a first power system 1, and secondary winding 5 is connected to a secondary power line 2, and secondary winding 8 is connected to a second power line through a power converter 9, and which gets the differential signal between the output signal from a power detector and the command value of power, and gets the speed differential signal between the output signal from the rotational speed detector 11 and the synchronous speed reference value, and outputs a control signal to the power converter, based on the differential signals of the power differential signal and the speed differential signal, and controls the secondary current of a second induction motor so as to control the rotational speed of a first induction motor. In this case, this is provided with a revolution conversion means 45 between the rotor of the first induction motor and the rotor of the second induction motor, and the rotor of the second induction motor 6 is rotated at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency converter including an induction machine and a power converter.

[0002]

2. Description of the Related Art FIG. 7 is a diagram showing a configuration of a frequency converter including a conventional induction motor and a power converter. An apparatus of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 6-269173. In FIG. 7, the first power system 1 is a system having a frequency of f1 [Hz], and the second power system 2 is different from the first power system 1 in a frequency of f2 [Hz].
It is a system of.

[0003] The primary winding 4 of the first winding induction machine 3 is connected to the first power system 1. The secondary winding 5 of the first winding induction machine 3 is connected to the second power system 2. The rotor (not shown) of the second wound induction machine 6 is mechanically coupled to the rotor (not shown) of the first wound induction machine 3, and its primary winding 7 is connected to the first winding 7. The secondary winding 8 is connected to the power system 1, and is connected to a static power converter 9 described later. The power converter 9 controls the current of the secondary winding 8, and the power detector 10 detects the power supplied from the first winding induction machine 3 to the first power system 1. The rotation speed detector (TG) 11 is mechanically coupled to the second winding induction machine 6, and detects the rotation speed of the first winding induction machine 3 or the second winding induction machine 6. .

[0004] The power flow control device 12 controls the power flow of the frequency converter. In the power flow control device 12, the power command value 13 is a command value of power flow control from the first power system 1 to the second power system 2, and is provided to the adder 14. The adder 14 detects a deviation between the power command value 13 and the power detector 10. The amplifier (AMP) 15 amplifies the deviation output from the adder 14.

On the other hand, the synchronous speed reference value 16 is such that the primary to secondary frequency ratio of the first coiled induction machine 3 is equal to the first power system 1.
And a rotation speed that matches the frequency ratio of the second power system 2. The adder 17 detects a deviation between the rotation speed detected by the rotation speed detector 11 and the speed reference value 16. The adder 18 outputs the output from the adder 17 and an amplifier (A
MP) 15 is detected. The amplification limiter 19 limits amplification of the control signal supplied from the adder 18.

FIG. 8 is a diagram showing an example of a circuit configuration of the static power converter 9. The stationary power converter 9
Self-extinguishing type switching elements 20 to 25 and diode 2
The secondary winding 8 of the second winding induction machine 6 comprises an inverter unit composed of 6-31, a converter unit composed of self-turn-off switching elements 32-37 and diodes 38-43, and a smoothing capacitor 44. AC excitation is performed.

In the above configuration, the power command value 13 is set to 0
, A control signal appears at the output of the amplitude limiter 19, and this control signal is given to the power converter 9. The power converter 9 controls the primary power of the second winding induction machine 6 according to the control signal. The direction of power is positive in the direction supplied from the induction machine to the power system, and the power supplied from the second winding induction machine 6 to the first power system 1 increases in the positive direction. That is, the second wirewound induction machine 6 acts as a generator, and reduces the rotation speed of the first wirewound induction machine 3. Therefore, the deviation signal between the rotation speed detected by the rotation speed detector 11 and the synchronous speed reference value 16 increases in the negative direction.

In addition, in proportion to the integral value of this deviation, the first
The phase angle with respect to the voltage of the second power system 2 in the secondary-side internal induced voltage of the wound-type induction machine 3 increases in the negative direction,
The phase angle of the primary-side internal induced voltage in the first wound induction machine 3 with respect to the voltage of the first power system 1 increases in the positive direction. As a result, the power supplied from the primary of the first winding induction machine 3 to the power system 1 increases in the positive direction, and is supplied to the power system 2 from the secondary of the first winding induction machine 3. Power increases in the negative direction.

When the output from the adder 17 increases in the negative direction and becomes larger than the output from the amplifier 15, the output polarity of the amplitude amplifier 19 is inverted, and the output of the second winding induction machine 6
The polarity of the next power is also inverted. At this time, the second wound induction machine 6 acts as an electric motor, and increases the rotation speed of the first wound induction machine 3. Therefore, the rotation speed detector 11
The deviation signal between the rotation speed and the synchronous speed reference value 16 detected at the step (1) decreases. Thus, the first wound induction machine 3
Is controlled so as to match the power command value, and in proportion to this, the secondary power of the first wound induction machine 3 increases in the negative direction.

[0010] Finally, the sum of the primary power of the first wound induction machine 3 and the primary power of the second wound induction machine 6 and the secondary power of the first wound induction machine 3 are calculated. The sizes are equal. At this time, power is supplied from the second power system 2 to the first power system 1.

When the power command value 13 is changed from 0 to a negative value in a stepwise manner, the power supplied from the second coiled induction machine 6 to the first power system 1 increases in the negative direction. That is, the second winding induction machine 6 acts as an electric motor,
The rotation speed of the first wound induction machine 3 is increased. Therefore, the deviation signal between the rotation speed detected by the rotation speed detector 11 and the synchronous speed reference value 16 increases in the positive direction. In proportion to the integral value of this deviation, the second winding type induction machine 3
The phase angle of the secondary-side internal induced voltage with respect to the voltage of the second power system 2 increases in the positive direction, and the first winding-type induction machine 3
At the primary side internal induced voltage with respect to the voltage of the first power system 1 increases in the negative direction. As a result, the power supplied from the primary of the first winding induction machine 3 to the power system 1 increases in the negative direction, and is supplied to the power system 2 from the secondary of the first winding induction machine 3. Power increases in the positive direction.

When the output from the adder 17 increases in the positive direction and becomes smaller than the output from the amplifier 15, the output polarity of the amplitude amplifier 19 is inverted, and the output of the second winding induction machine 6
The polarity of the next power is also inverted. At this time, the second coiled induction machine 6 acts as a generator, and reduces the rotation speed of the first coiled induction machine 3. Therefore, the deviation signal between the rotation speed detected by the rotation speed detector 11 and the synchronous speed reference value 16 becomes small. Thus, the first wound induction machine 3
Is controlled so as to match the power command value, and the secondary power of the first wound induction machine 3 increases in proportion thereto.

Finally, the sum of the primary power of the first winding induction machine 3 and the primary power of the second winding induction machine 6 and the secondary power of the first winding induction machine 3 are calculated. The sizes are equal. At this time, power is supplied from the first power system 1 to the second power system 2. As described above, the device of FIG. 7 functions as a frequency conversion device.

[0014]

In the above-described conventional configuration, the rotor of the first wound induction machine 3 and the rotor of the second wound induction machine 6 are directly mechanically connected. . Therefore, the rotation speed of the second winding induction machine 6 and the rotation speed of the first winding induction machine 3 become equal, and the torque becomes the same.
However, since the outer dimensions of the wound-type induction machine are determined by the torque, a large induction machine equivalent to the first wound-type induction machine 3 is required as the second wound-type induction machine 6.

The first winding type induction machine 3 uses an induction machine of a direct high voltage connection type so that the primary winding of the first winding type induction machine 3 can be operated even if the first power system 1 has a high voltage. Wires can be connected directly. At this time, the second winding type induction machine 6
When the primary winding is connected to the first electric power system 1, a direct high-voltage connection type induction machine is required as the second winding induction machine 6 in the same manner as the first winding induction machine 3, resulting in an increase in cost. I do.

Although the second winding type induction machine 6 controls the three-phase excitation current by the power converter 9, this power converter 9 has a problem that it has a large number of parts, is complicated, and is expensive. is there.

A first object of the present invention is to provide a frequency converter capable of controlling the rotation speed of an induction machine using an induction machine having a small external dimension. Second embodiment of the present invention
It is an object of the present invention to provide a frequency converter for reducing the cost of an induction machine. A third object of the present invention is to provide a frequency conversion device for reducing the cost of the entire device.

[0018]

Means for Solving the Problems In order to solve the above-mentioned problems and achieve the object, a frequency conversion device of the present invention is configured as follows. (1) The frequency converter of the present invention mechanically couples the rotor of the first induction machine and the rotor of the second induction machine, and connects the primary winding of the first induction machine to the primary winding. The primary winding of the second induction machine is connected to a first power system, the secondary winding of the first induction machine is connected to a second power system, and the secondary winding of the second induction machine is connected. Connecting a line to the second power system via a power converter;
A power deviation signal between an output signal from a power detector provided on a primary winding side of the first and second induction machines and a power command value is obtained, and the first induction machine or the second induction machine is obtained. Determining a speed deviation signal between the output signal from the rotation speed detector of the machine and the synchronous speed reference value, and outputting a control signal to the power converter based on the power deviation signal and a deviation signal of the speed deviation signal; A frequency converter for controlling a secondary current of a second induction machine to control a rotation speed of the first induction machine, wherein a rotor of the first induction machine and a rotor of the second induction machine are controlled. And a rotation speed converting means for rotating the rotor of the second induction machine at a high speed.

(2) The frequency converter of the present invention mechanically couples the rotor of the first induction machine and the rotor of the second induction machine to form a primary winding of the first induction machine. Is connected to a first power system, a secondary winding of the first induction machine is connected to a second power system, and a secondary winding of the second induction machine is connected via a power converter. A power deviation signal between an output signal from a power detector provided on a primary winding side of the first induction machine and a command value of power, the first induction machine being connected to a second power system; Alternatively, a speed deviation signal between an output signal from a rotation speed detector of the second induction machine and a synchronous speed reference value is obtained, and the power converter is controlled based on the power deviation signal and a deviation signal of the speed deviation signal. A frequency converter that outputs a signal and controls the secondary current of the second induction machine to control the rotation speed of the first induction machine. Te, was connected to the primary winding of the second induction machine to said second power system.

(3) The frequency converter according to the present invention is the device according to (2) above, and further includes a rotation speed between the rotor of the first induction machine and the rotor of the second induction machine. A converter is provided for rotating the rotor of the second induction machine at a higher speed than the rotor of the first induction machine.

(4) The frequency conversion device of the present invention is the device described in (1) or (2) above, and
Is constituted by a two-axis excitation synchronous machine, and the d-axis winding of the two-axis excitation synchronous machine is DC-excited by a DC excitation power converter for the d-axis winding. The shaft winding is DC-excited by a DC excitation power converter for the q-axis winding.

As a result of taking the above-described measures, the following effects are obtained. (1) According to the frequency converter of the present invention, a rotation speed converter is provided between the first induction machine and the second induction machine,
Since the second induction machine is rotated at a high speed, the rotation speed of the first induction machine can be controlled even if an induction machine having a small external dimension is used as the second induction machine.

(2) According to the frequency converter of the present invention,
By connecting the primary winding of the second induction machine to the second power system and lowering the voltage of the second power system, it is not necessary to take high-voltage insulation measures for the second induction machine. The cost of the machine can be reduced and the maintenance management can be improved.

(3) According to the frequency converter of the present invention,
Since the rotor of the second induction machine is rotated at a higher speed than the rotor of the first induction machine, the torque required for the same output is reduced. The device can be configured using an induction machine.

(4) According to the frequency converter of the present invention,
The second induction machine is replaced with a two-axis excitation synchronous machine, and the secondary-side d-axis winding and the q-axis winding of the two-axis excitation synchronous machine are each DC-excited by a simple power converter, thereby reducing the cost. It is possible to configure a frequency conversion device.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a circuit configuration diagram of a frequency conversion device according to a first embodiment of the present invention. In FIG. 1, the same portions as those in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 1, the conversion ratio of a rotation speed conversion device (for example, a gear) 45 is k.
Rotor of first wound induction machine 3 and second wound induction machine 6
Is mechanically coupled to the rotor via a rotation speed converter 45. When the rotation speed of the first winding induction machine 3 is fr1, the rotation speed fr2 of the second winding induction machine 6 is fr2 = k · fr1. Here, it is assumed that the conversion ratio k is k> 1, and that the rotation speed of the second coiled induction machine 6 is higher than the rotation speed of the first coiled induction machine 3.

When the power command value 13 is increased stepwise from 0, a control signal appears on the output from the amplitude limiter 19, and this control signal is given to the power converter 9. The power converter 9 controls the primary power of the second winding induction machine 6 according to the control signal. Since the direction of the power is positive in the direction from the induction machine to the power system, the power supplied from the second winding induction machine 6 to the first power system 1 increases in the positive direction, and Winding induction machine 6 acts as a generator.

When the second winding induction machine 6 acts as a generator, a deceleration torque acts on the first winding induction machine 3 and the rotation speed of the first winding induction machine 3 decreases. as a result,
The rotation speed of the second winding induction machine 6 connected via the rotation speed conversion device 45 also decreases in accordance with the conversion ratio k of the rotation speed conversion device 45, and the rotation speed detected by the rotation speed detector 11 and the synchronous speed The deviation signal from the reference value 16 increases in the negative direction.

Further, in proportion to the integral value of the deviation, the first
The phase angle with respect to the voltage of the second power system 2 in the secondary-side internal induced voltage of the wound-type induction machine 3 increases in the negative direction,
The phase angle with respect to the voltage of the first power system 1 in the primary-side internal induced voltage of the first wirewound induction machine 3 increases in the positive direction. As a result, the power supplied from the primary of the first winding induction machine 3 to the first power system 1 increases in the positive direction,
The electric power supplied from the secondary of the first wound induction machine 3 to the second electric power system 2 increases in the negative direction.

When the output from the adder 17 increases in the negative direction and becomes larger than the output from the amplifier 15, the output polarity of the amplitude amplifier 19 is inverted, and the output of the second winding induction machine 6 is changed.
The polarity of the next power is also inverted. At this time, the second winding induction machine 6 acts as an electric motor. When the second winding induction machine 6 acts as an electric motor, an acceleration torque acts on the first winding induction machine 3, and the rotation speed of the first winding induction machine 3 increases. As a result, the rotation speed of the second winding induction machine 6 connected via the rotation speed conversion device 45 also increases.
The deviation signal between the rotation speed detected by the rotation speed detector 11 and the synchronous speed reference value 16 increases in the positive direction. Further, the deviation signal between the rotation speed detected by the rotation speed detector 11 and the synchronous speed reference value 16 decreases.

In this way, the primary power of the first wirewound induction machine 3 is controlled to match the power command value 13,
In proportion to this, the secondary power of the first wound induction machine 3 increases in the negative direction. Eventually, the sum of the primary power of the first winding induction machine 3 and the primary power of the second winding induction machine 6 and the magnitude of the secondary power of the first winding induction machine 3 are Become equal.
At this time, power is supplied from the second power system 2 to the first power system 1.

When the power command value 13 is changed from 0 to a negative value in a stepwise manner, the power supplied from the second winding induction machine 6 to the first power system 1 increases in the negative direction. That is, the second wound induction machine 6 acts as an electric motor. When the second winding induction machine 6 acts as an electric motor,
Acceleration torque acts on the first wound induction machine 3 to increase the rotation speed of the first wound induction machine 3. As a result, the rotation speed of the second winding induction machine 6 connected via the rotation speed conversion device 45 also increases in accordance with the conversion ratio k of the rotation speed conversion device 45, and the deviation signal from the synchronous speed reference value 16 becomes positive. Increase in the direction. At this time, the deviation signal between the rotation speed detected by the rotation speed detector 11 and the synchronous speed reference value 16 increases in the positive direction.

In proportion to the integral value of the deviation, the phase angle of the secondary-side internal induced voltage of the first wound induction machine 3 with respect to the voltage of the second power system 2 increases in the positive direction, The phase angle of the primary-side internal induced voltage of the wound induction machine 3 with respect to the voltage of the first power system 1 increases in the negative direction.
As a result, the power supplied from the primary of the first winding induction machine 3 to the power system 1 increases in the negative direction, and is supplied to the power system 2 from the secondary of the first winding induction machine 3. Power increases in the positive direction.

When the output from the adder 17 increases in the positive direction and becomes smaller than the output from the amplifier 15, the output polarity of the amplitude amplifier 19 is inverted, and the output of the second winding induction machine 6
The polarity of the next power is also inverted. At this time, the second coiled induction machine 6 acts as a generator. When the second coiled induction machine 6 acts as a generator, a deceleration torque acts on the first coiled induction machine 3 and the rotation speed of the first coiled induction machine 3 decreases. As a result, the rotation speed of the second winding induction machine 6 connected via the rotation speed conversion device 45 also increases.
The rotation speed is reduced in accordance with the conversion ratio k of 5, and the deviation signal between the rotation speed detected by the rotation speed detector 11 and the synchronous speed reference value 16 increases in the negative direction. Further, the deviation signal between the rotation speed detected by the rotation speed detector 11 and the synchronous speed reference value 16 becomes smaller.

In this way, the primary power of the first wirewound induction machine 3 is controlled to match the power command value 13,
In proportion to this, the secondary power of the first winding induction machine 3 increases. Eventually, the sum of the primary power of the first winding induction machine 3 and the primary power of the second winding induction machine 6 and the magnitude of the secondary power of the first winding induction machine 3 are Become equal. At this time,
Power is supplied from the first power system 1 to the second power system.

Therefore, since the rotor of the second wound induction machine 6 rotates faster than the rotor of the first wound induction machine 3, the required torque for the same output is reduced. The frequency converter can be configured by using the second winding type induction machine 6 as an induction machine having a small external dimension.

(Second Embodiment) FIG. 2 is a circuit configuration diagram of a frequency conversion device according to a second embodiment of the present invention. In FIG. 2, the same portions as those in FIGS. 1 and 7 are denoted by the same reference numerals, and description thereof will be omitted.

In the case of FIG. 1, if the primary winding 4 of the first winding induction machine 3 is on the stator side, the secondary winding 5 is on the rotor side, and the The connection is made via a slip ring and a brush (not shown). At this time, if an induction machine of a direct high voltage connection system with insulation measures is used, the stator side can be directly connected to a high voltage power system. However, on the rotor side, the voltage of the secondary winding must be kept low for reasons such as brush insulation measures and maintenance management. Therefore, when the voltage of the second power system 2 is high, the voltage of the Connection.

Similarly to the first winding-type induction machine 3, when the second winding-type induction machine 6 uses an induction machine of a direct high-voltage connection type, the stator side of the primary winding 7 has a high-voltage power system. Can be connected to However, although the capacity of the second wire-wound induction machine 6 is smaller than that of the first wire-wound induction machine 3, if a direct high-voltage connection type induction machine is applied, the size of the induction machine becomes large due to insulation measures and the like. .

On the other hand, in FIG. 2, the primary winding 7 of the second wound induction machine 6 is connected to the second power system 2 to reduce the insulation measures of the second wound induction machine 6. Thus, the size of the second wound induction machine 6 can be reduced.

Finally, the primary power of the first wound induction machine 3, the secondary power of the first wound induction machine 3 and the primary winding of the second induction machine 6 The sum with the power supplied to the power system 2 becomes equal. When the second wound induction machine 6 is operating as a generator, power is supplied from the second power system 2 to the first power system 1, and the second wound induction machine 6 operates as a motor. Power is supplied from the first power system 1 to the second power system 2.

(Third Embodiment) FIG. 3 is a circuit diagram of a frequency converter according to a third embodiment of the present invention. 3, the same parts as those in FIGS. 1, 2, and 7 are denoted by the same reference numerals, and description thereof will be omitted. 3 is different from FIG. 7 in that a two-axis excitation synchronous machine 6 'having a secondary winding composed of a d-axis and a q-axis is used for the second winding induction machine 6, and a d-axis winding on the rotor side is used. At the point where the wire 46 is connected to the second power system 2 via the DC excitation power converter 48 and the q-axis winding 47 is connected to the second power system 2 via the DC excitation power converter 49. is there.

FIG. 4 is a circuit diagram of the DC excitation power converter 48. As shown in FIG. The DC excitation power converter 48 includes thyristors 50 to 55, and excites the d-axis winding 46 in the positive direction of the d-axis only in accordance with a control signal from the amplitude limiter 19 of the power flow controller 12.

FIG. 5 is a circuit diagram of the DC excitation power converter 49. The DC excitation power converter 49 includes thyristors 56 to 67, and excites the q-axis winding 47 in the positive and negative directions according to a control signal from the amplitude limiter 19 of the power flow controller 12.

FIG. 6 is a diagram for explaining the operation of the two-axis excitation synchronous machine 6 '. D-axis winding 4 of two-axis excitation synchronous machine 6 '
6 is the main magnetic flux direction, and the q-axis winding 47 is a magnetic flux direction orthogonal to the d-axis winding 46. The d-axis winding 46 performs DC excitation only in the positive direction by the d-axis DC excitation power converter 48. At this time, when the q-axis winding 47 is DC-excited in the positive direction by the d-axis DC excitation power converter 49 and operates in the first quadrant, the two-axis excitation synchronous machine 6 'operates as a generator. . When the q-axis winding 47 is DC-excited in the negative direction by the q-axis DC excitation power converter 49 and is operated in the second quadrant, the two-axis excitation synchronous machine 6 'operates as a motor.

In this manner, the d-axis DC excitation power converter 48 and the q-axis DC excitation power converter 49 are different from the conventional three-phase excitation power converter 9 shown in FIG. , Circuits and control can be easily configured. The present invention is not limited to only the above embodiments, and can be implemented with appropriate modifications without departing from the scope of the invention.

[0047]

According to the present invention, the rotor of the first induction machine and the rotor of the second induction machine are mechanically connected via the rotation speed converter, and the conversion of the rotation speed converter is performed. The second
By increasing the rotation speed of the induction machine to a rotation speed higher than the rotation speed of the first induction machine, the rotation speed of the first induction machine can be reduced even if the second induction machine is an induction machine having a small external dimension. Can be controlled. This can reduce equipment costs and installation costs, save installation space, and facilitate maintenance.

Further, according to the present invention, the first induction machine uses an induction machine of a direct high voltage connection type with insulation measures taken, and the primary winding of the second induction machine is connected to the second power system. By connecting, the frequency converter can be connected while the first power system is kept at a high voltage, and it is not necessary to provide a high-voltage insulation measure or an interconnecting transformer to the second induction machine, which reduces equipment cost and cost. This is advantageous in terms of maintenance management.

According to the present invention, the second induction machine is
A low-cost frequency converter can be configured by using a shaft excitation synchronous machine and performing DC excitation on the secondary side of the two-axis excitation synchronous machine with a simple power converter.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a frequency conversion device according to a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a frequency conversion device according to a second embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a frequency conversion device according to a third embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a DC excitation power converter according to a third embodiment of the present invention.

FIG. 5 is a circuit configuration diagram of a DC excitation power converter according to a third embodiment of the present invention.

FIG. 6 is an operation explanatory diagram of a two-axis excitation synchronous machine according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram of a frequency conversion device according to a conventional example.

FIG. 8 is a diagram showing an example of a circuit configuration of a static power converter according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st electric power system 2 ... 2nd electric power system 3 ... 1st winding type induction machine 4 ... 1st winding of 1st winding type induction machine 5 ... 2nd winding of 1st winding type induction machine Line 6: Second winding type induction machine 6 '... Biaxial excitation synchronous machine 7 ... Primary winding of second winding type induction machine 8 ... Secondary winding of second winding type induction machine 9 ... Power conversion Device 10 Power detector 11 Rotation speed detector 12 Power flow controller 13 Power command value 14 Adder 15 Amplifier 16 Synchronous speed reference value 17 Adder 18 Adder 19 Amplitude limiter 20 to 25 Self-extinguishing switching elements 26-31 Diodes 32-37 Self-extinguishing switching elements 38-43 Diodes 44 Smoothing capacitors 45 Rotational speed converters 46 D-axis winding of two-axis excitation synchronous machine Line 47: q-axis winding of two-axis excitation synchronous machine 48: d-axis winding DC excitation power Converter 49 ... winding DC excitation power converter 50-67 ... thyristor q-axis

 ──────────────────────────────────────────────────続 き Continued on the front page (71) Applicant 000003078 Toshiba Corporation 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa (72) Inventor Hiroshi Uchino 1 Shibafu Engineering Co., Ltd. (72 ) Inventor Shinichi Nohara 66-2 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Pref. Toshiba Engineering Service Co., Ltd. (72) Inventor Yukio Kadoda 1 Toshiba-cho, Fuchu-shi, Tokyo 5H750 BA03 CC03 CC04 CC14 DD01 DD14 DD18 FF11

Claims (4)

[Claims] A rotor of a first induction machine and a rotor of a second induction machine are mechanically coupled to each other, and a primary winding of the first induction machine and one of the second induction machine are connected. A secondary winding is connected to a first power system, a secondary winding of the first induction machine is connected to a second power system, and a secondary winding of the second induction machine is connected to a power converter. A power deviation signal between an output signal from a power detector provided on a primary winding side of the first and second induction machines and a power command value, A speed deviation signal between an output signal from the rotation speed detector of the first induction machine or the second induction machine and a synchronous speed reference value is obtained, and a deviation signal between the power deviation signal and the speed deviation signal is determined. A frequency converter that outputs a control signal to the power converter, controls a secondary current of the second induction machine, and controls a rotation speed of the first induction machine. A rotation speed converting means is provided between the rotor of the first induction machine and the rotor of the second induction machine, and the rotor of the second induction machine is rotated at a high speed. Frequency conversion device. 2. The method according to claim 1, wherein a rotor of the first induction machine is mechanically coupled to a rotor of the second induction machine, and a primary winding of the first induction machine is connected to a first power system. Connecting a secondary winding of the first induction machine to a second power system, connecting a secondary winding of the second induction machine to the second power system via a power converter, A power deviation signal between an output signal from a power detector provided on a primary winding side of the first induction machine and a power command value is obtained, and rotation of the first induction machine or the second induction machine is determined. Calculating a speed deviation signal between an output signal from a speed detector and a synchronous speed reference value; outputting a control signal to the power converter based on a deviation signal between the power deviation signal and the speed deviation signal; In a frequency converter for controlling a secondary current of an induction machine to control a rotation speed of the first induction machine, a primary winding of the second induction machine Is connected to the second power system. 3. A rotating speed converting means is provided between a rotor of said first induction machine and a rotor of said second induction machine,
The frequency converter according to claim 2, wherein the rotor of the induction machine is rotated at a higher speed than the rotor of the first induction machine. 4. The second induction machine comprises a two-axis excitation synchronous machine, and a d-axis winding of the two-axis excitation synchronous machine is DC-excited by a DC excitation power converter for the d-axis winding; 3. The frequency converter according to claim 1, wherein the q-axis winding of the two-axis excitation synchronous machine is DC-excited by a DC-excitation power converter for the q-axis winding.