JPH1023745A - Power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent communication disturbance by effectively reducing the zero-phase-sequence component of a three-phase input or output current, by constituting the converter so that the converter can represent little reactance to the positive- and negative-phase-sequence components of the current, but sufficiently large reactance to the zero-phase-sequence component. SOLUTION: A three-phase voltage PWM power inverter device 30 is constituted of a PWM power inverter 1, a filter 2, and a reactor 6. The converter 1 is constituted of six switch elements 11-16 respectively composed of transistors and diodes and one capacitor 17, and connected between an AC power source 4 and a load 5 through the filter 2 and the reactor 6. The filter 2 is composed of three pairs of serial reactors 21-26, capacitors 27-29 connected in series, and resistors 291-293 one ends of which are connected to each other. The reactor 6 is composed of three-phase coils 61-63 wound around a common magnetic core 64. The coils 61-63 are closely coupled with each other so that each coil 61-63 can have sufficiently large reactance. Consequently, the reactance of the reactor 6 in three phases becomes zero and the zero-phase reactance of the reactor 6 becomes larger. Therefore, the communication disturbance can be prevented by making the zero-phase current smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter for performing AC / DC mutual conversion.

[0002]

2. Description of the Related Art FIG. 10 shows, for example, IEEJ Technical Report (Part II) No. 425, "Active Filter Technology for Electric Power".
3 is a circuit diagram and operation waveforms showing a pulse width modulation (PWM) control power converter as a conventional three-phase power converter shown on page 14 or 21 and 22 of FIG.

In FIG. 10A, reference numeral 3 denotes a conventional three-phase voltage-type PWM inverter, which is a three-phase voltage-type PWM inverter.
The inverter 3 includes a three-phase voltage-type PWM inverter 1 and a filter 2.

A three-phase voltage source PWM inverter 1 has six switch elements 11 to 11 each including a transistor and a diode.
16 and one DC capacitor 17, and three pairs of switch elements 11, 14; 1 connected in series with each other.
13, 15; 13 and 16 are connected in parallel to a DC capacitor 17, and each pair of switch elements 11, 14;
15; 13, 16 is connected between the three-phase AC power supply 4 and the load 5 via the filter 2.

[0005] The filter 2 is composed of three filters connected in series.
Pair reactors 21, 24; 22, 25; 23, 26
And each pair of reactors 21, 24; 22, 25; 23,
26, a capacitor 27 connected in series with each other
To 29 and resistors 291 to 293, and one ends of the resistors 291 to 293 are connected to each other. The three pairs of reactors 21, 24; 22, 25; 23, 26 are an intermediate point between the three-phase AC power supply 4 and the load 5 and three pairs of switch elements 1.
1, 14; 12, 15; 13, and 16 are connected in series.

Reference numeral 1001 denotes a ground capacitance of the three-phase voltage source PWM inverter 1, and 1002 denotes a ground capacitance of the three-phase AC circuit.

FIG. 10 (b) shows a three-phase output of the three-phase voltage type PWM inverter 1 and a three-phase line voltage VI and a three-phase voltage type P.
Current I flowing between WM inverter 3 and three-phase AC power supply 4
C, and the other two phases also have similar waveforms of voltages and currents that are 120 degrees out of phase with these.

Next, the operation of this conventional example will be described. The voltage V on the three-phase AC side of the three-phase voltage type PWM inverter 1
I is a pulse train obtained by cutting out the DC voltage of the DC capacitor 17 for a predetermined time width by switching the switches 11 to 16 as shown in the waveform of FIG. Is a three-phase voltage type P
The required AC voltage to be generated by the WM inverter 1. The magnitude of the fundamental wave changes by controlling each pulse width, and the voltage of the three-phase AC power supply 4 is constant. Therefore, the relationship between the magnitude and the phase of the two voltages, and mainly the reactance of the reactors 21 to 26 of the filter 2 And a current IC determined by the following.

In the conventional example of FIG. 10, the current IC is a three-phase voltage type PWM so that the three-phase AC power supply 4 becomes a reactive current.
The fundamental of the voltage VI of the inverter 1 is controlled to compensate for the power factor of the load 5. The pulse train is controlled by the control method and the switch 11.
With the performance of ~ 16, there are several to several hundred pulses in a half cycle of the voltage of the three-phase AC power supply 4. Naturally, the voltage VI includes a large amount of harmonics other than the fundamental wave.
Has a waveform close to a sine wave. In this case, as the harmonic component remaining in the current IC, the three-phase voltage-type PWM inverter 3
And the one flowing to the ground by the three-phase voltage source PWM inverter 1 and the three-phase AC circuit ground capacitances 1001 and 1002 (in FIG. 10 (a)). IG for one of the three phases). Those that flow only through the conductor are limited to the positive phase component and the negative phase component in the harmonics, and those that flow from the conductor to the ground via the ground capacitances 1001 and 1002 include other zero phase components.

[0010]

Since the above-mentioned conventional three-phase power converter is constructed as described above, the three-phase voltage caused by the harmonics of the voltage VI of the three-phase voltage source PWM inverter 1 is obtained. It has been difficult to sufficiently reduce induction disturbance to a communication line provided in proximity to the three-phase AC circuit or buried in the ground due to harmonics of the AC current IC of the PWM inverter 3. That is, since the sum of the three phases is zero for the positive phase component and the negative phase component among the harmonics, the three-phase AC circuit is controlled so that the induction from each phase of the three-phase AC circuit to the communication line is almost the same. By maintaining the inductive coupling relationship between each phase and the communication line, the induction disturbance due to the positive phase component and the reverse phase component can be sufficiently reduced, but the zero phase component causes the three phases to be added to each other to cause the induction disturbance.

Therefore, in order to sufficiently reduce inductive interference,
Although the zero-phase component must be effectively reduced, if this purpose is to be achieved by the filter 2 in the above-described conventional example, it is necessary to increase the reactance of the reactors 21 to 26. However, if the reactance is increased, the component of the fundamental wave of the current IC decreases, or if the same current IC flows, the voltage drop of the reactors 21 to 26 increases.
The voltage VI must be increased, and the three-phase voltage type PWM
There is a problem that the capacity of the inverter 1 becomes large.

The ground capacitances 1001, 100
Since it is difficult to arbitrarily select 2 as a small value, this cannot reduce the zero-phase component.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and provides a power converter capable of effectively reducing a zero-phase component included in a three-phase alternating current of the power converter. The purpose is to:

[0014]

According to the first aspect of the present invention, there is provided a power converter that exhibits little reactance with respect to a positive phase component and a negative phase component in a three-phase AC input current or a three-phase AC output current. , And a zero-phase current suppression reactor configured to exhibit a sufficient reactance with respect to the zero-phase component.

In the power converter according to a second aspect of the present invention, the three-phase power converter is connected between a three-phase AC power supply and a load via a filter and a zero-phase current suppression reactor, and the zero-phase current suppression is performed. The reactor is configured so that it shows little reactance to the positive phase component and negative phase component in the three-phase AC input current or three-phase AC output current, and exhibits sufficient reactance to the zero-phase component It is.

According to a third aspect of the present invention, the power converter includes the zero-phase current suppression reactor on a three-phase AC side.

According to a fourth aspect of the present invention, in the power converter, the zero-phase current suppressing reactor includes a three-phase coil on a common iron core, a close magnetic coupling between the coils, and a sufficient reactance by each coil alone. It is configured to be wound so as to have.

According to a fifth aspect of the present invention, in the power converter, the three-phase power converter comprises a three-phase voltage source PWM forward converter.

According to a sixth aspect of the present invention, in the power converter, the three-phase power converter includes a three-phase voltage source PWM inverter.

According to a seventh aspect of the present invention, in the power converter, the three-phase power converter comprises a three-phase separately-excited uncontrolled current source forward converter.

According to an eighth aspect of the present invention, in the power converter, the three-phase separately-excited non-controlled current source forward converter is connected to the load, and a diode rectifier is connected in series between the diode rectifier and the load. And a connected DC reactor.

According to a ninth aspect of the present invention, in the power converter, the three-phase power converter comprises a three-phase separately-excited non-control voltage-type forward converter.

According to a tenth aspect of the present invention, there is provided a power converter,
A diode rectifier in which the three-phase separately-excited uncontrolled voltage source forward converter is connected to the load; a DC reactor connected in series between the diode rectifier and the load; and a diode rectifier and the load. And a capacitor connected in parallel between them.

An eleventh aspect of the present invention is a power converter.
The three-phase power converter comprises a three-phase separately excited current type reversible converter.

According to a twelfth aspect of the present invention, there is provided a power converter.
The three-phase separately excited current type reversible converter includes a thyristor rectifier including a plurality of thyristors and a DC reactor connected in series between the thyristor rectifier and the load.

A power converter according to a thirteenth aspect of the present invention
The three-phase power converter includes a three-phase separately-excitable controllable voltage-type nonreciprocal forward converter.

According to a fourteenth aspect of the present invention, a power converter
The three-phase separately-excited controllable voltage-type irreversible forward converter includes a thyristor rectifier including a plurality of thyristors, a DC reactor connected in series between the thyristor rectifier and the load, the thyristor rectifier and the load. And a capacitor connected in parallel between the two.

A power converter according to a fifteenth aspect of the present invention
The three-phase power converter is constituted by a three-phase separately excited voltage type reversible converter.

The power converter according to the invention of claim 16 is:
The three-phase separately-excited voltage-type reversible converter, a reversible thyristor rectifier including a plurality of thyristors connected in parallel with opposite polarities to each other, and a DC reactor connected in series between the reversible thyristor rectifier and the load, And a capacitor connected in parallel between the reversible thyristor rectifier and the load.

A power converter according to a seventeenth aspect of the present invention is
A three-phase power forward converter having a first zero-phase current suppression reactor on a first three-phase AC side and a three-phase power reverse conversion having a second zero-phase current suppression reactor on a second three-phase AC side The first and second zero-phase current suppression reactors exhibit little reactance with respect to the positive-phase component and the negative-phase component in the three-phase AC input current or the three-phase AC output current, It is configured to exhibit a sufficient reactance with respect to the zero-phase component.

The power converter according to the invention of claim 18 is:
The three-phase power forward converter comprises a three-phase PWM forward converter, and the three-phase power reverse converter comprises a three-phase PWM reverse converter.

A power converter according to a nineteenth aspect of the present invention
The three-phase PWM forward converter includes a three-phase voltage-type PWM forward converter connected to a three-phase AC power supply via a first filter and the first zero-phase current suppression reactor. A PWM inverter, comprising a three-phase voltage source PWM inverter connected to a load via a second filter and the second zero-phase current suppression reactor, wherein the three-phase voltage source PWM
The M forward converter and the three-phase voltage source PWM inverter are connected to each other.

[0033] According to a twentieth aspect of the power converter,
The three-phase power forward converter comprises a three-phase separately-excited reversible power forward converter, and the three-phase power inverter comprises a three-phase separately-excited reversible power reverse converter.

The power converter according to the twenty-first aspect of the present invention
The three-phase separately-excited reversible power forward converter includes a thyristor rectifier connected to a first three-phase AC power supply via a first filter and the first zero-phase current suppression reactor, and the three-phase separately excited A reversible power inverter, comprising: a thyristor inverter connected to a second three-phase AC power supply or a three-phase back electromotive force load via a second filter and the second zero-phase current suppression reactor; The thyristor rectifier and the thyristor reverse converter are connected to each other via a DC reactor.

[0035]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the embodiments described below and the conventional example described above, the same portions are denoted by the same reference numerals.

Embodiment 1 FIGS. 1A and 1B show a three-phase voltage type PWM inverter as a power converter according to a first embodiment of the present invention. FIG. 1A is a circuit diagram thereof, and FIG. 1B is a first to ninth embodiments of the present invention. 1 shows a configuration example of a zero-phase current suppression reactor used for the present invention.

Referring to FIG. 1A, a three-phase voltage source PWM inverter 30 according to the present invention comprises a three-phase voltage source PWM inverter 1, a filter 2, and a zero-phase current suppression reactor 6. ing.

The three-phase voltage-type PWM inverter 1 is composed of six switch elements 11 to 16 composed of transistors and diodes and one DC capacitor 17 in the same manner as in the conventional example shown in FIG. And three pairs of switch elements 11, 14; 12, 15; 1 connected in series with each other.
3 and 16 are connected in parallel to a DC capacitor 17, and each pair of switch elements 11, 14; 12, 15;
The intermediate connection point between 3 and 16 is connected between the three-phase AC power supply 4 and the load 5 via the filter 2 and the zero-phase current suppression reactor 6.

Similarly to the conventional example shown in FIG. 10A, the filter 2 also includes three pairs of reactors 21, 24; 22, 25, 23, and 26 connected in series with each other, and each pair of reactors 21. , 24; 22, 25; 23, 26, the capacitors 27 to 29 and the resistors 291 to 293 connected in series with each other.
Are connected to each other. Three pairs of reactors 2
1, 24; 22, 25; 23, and 26 are intermediate points between the three-phase AC power supply 4 and the load 5 and three pairs of switch elements 11, 14;
2, 15; and 13 and 16, respectively, are connected in series.

As shown in FIG. 1B, the zero-phase current suppressing reactor 6 includes a common magnetic core 64 and three-phase coils 61, 62, 63 wound around the common magnetic core 64. The three-phase coils 61, 62, and 63 are wound around a common magnetic core 64 so as to make the mutual magnetic coupling between the coils dense and to have sufficient reactance by each coil alone. Since the three-phase sum of the positive phase component and the negative phase component of the current flowing through the three-phase coils 61, 62, 63 is zero, the magnetic flux in the magnetic core due to these components, and thus the reactance for these components, becomes zero. Since the magnetic fluxes generated by the three-phase coils are added to each other, a large reactance is exhibited for the zero-phase component.

Reference numeral 1001 denotes a ground capacitance of the three-phase voltage source PWM inverter 1, and 1002 denotes a ground capacitance of the three-phase AC circuit.

Next, the operation of the first embodiment will be described. Switch element 1 of three-phase voltage source PWM inverter 1
1 to 16 are turned on and off in accordance with the control signal to cut out the voltage of the DC capacitor 17, and generate a pulse train VI having the amplitude of the voltage of the DC capacitor 17 on the three-phase AC side of the three-phase voltage source PWM inverter 1. This pulse train VI has a fundamental wave voltage having the same cycle as the voltage of the three-phase AC power supply 4. The magnitude and phase relationship between the fundamental wave voltage and the voltage of the three-phase AC power supply 4, and mainly the filter 2 Reactor 2
A current IC determined by reactances 1 to 26 flows through each line on the three-phase AC side of the voltage-type PWM inverter 30.

Since the voltage VI generated by the three-phase voltage-type PWM inverter 1 is a pulse train, the voltage VI has a large amount of harmonic components in addition to the fundamental wave. The current flowing in the three-phase AC circuit connected to the three-phase voltage source PWM inverter 30 has a substantially sine wave.
However, it still contains residual harmonic components, and in particular, the zero-phase component thereof causes inductive interference in a communication line close to a three-phase AC circuit and a communication line arranged on the ground.

In the present invention, since the zero-phase current suppressing reactor 6 is configured as described above, the magnetic flux due to the currents of the three-phase positive and negative phases is zero, and therefore, the reactance for these currents is zero. At zero, the magnetic flux due to the zero-phase component of each of the three-phase currents is mutually added to the zero-phase component current, thereby exhibiting a large reactance, thereby effectively reducing the zero-phase component. That is, the zero-phase component, which is a major cause of the induction disturbance on the communication line, can be reduced without affecting the three-phase AC fundamental current originally required for the three-phase voltage source PWM inverter 30.

As the zero-phase current suppressing reactor 6, each of the three-phase windings needs a current capacity capable of passing a fundamental wave current, but the core used as the common core 64 does not saturate with respect to the zero-phase current. Since the zero-phase current is sufficiently smaller than the fundamental wave current, the zero-phase current suppression reactor 6
Can be small and economical.

In the first embodiment, the zero-phase current suppressing reactor 6 is shown as being provided on the side of the AC power supply 4 of the filter 2. However, the three-phase voltage source PWM inverter 1 It may be provided on the side.

Embodiment 2 In the first embodiment, the case where the zero-phase current suppression reactor 6 is provided on the three-phase AC side when the three-phase power converter is the three-phase voltage type PWM inverter 30 is described. , As shown in FIG.
Even when the three-phase power converter is the three-phase voltage-type PWM forward converter 32, it can be provided on the three-phase AC side.

FIG. 2 shows a second embodiment configured as described above. 2, a three-phase voltage-type PWM forward converter 32 includes a three-phase voltage-type PWM forward converter 7 and a filter 2.
1 and a zero-phase current suppression reactor 600. The three-phase voltage source PWM forward converter 7 includes switch elements 71 to 76 and a DC capacitor 77 similar to the switch elements 11 to 16 and the DC capacitor 17 of FIG. The configuration is substantially the same as that of the three-phase voltage source PWM inverter 1 of FIG. A DC load 8 is connected to the three-phase voltage source PWM forward converter 7 in parallel with a DC capacitor 77, and power is supplied from the three-phase AC power supply 4 via the zero-phase current suppression reactor 600, the filter 200, and the PWM forward converter 32. Supplied. The filter 200 includes reactors 221 to 226, capacitors 227 to 229, and resistors 2291 to 2293, and is configured similarly to the filter 2 of FIG. Further, the zero-phase current suppression reactor 600 also includes three-phase coils 661, 662,
66 and a common magnetic core 664, and are configured similarly to the zero-phase current suppression reactor 6 of FIG.

The filter 200, the zero-phase current suppressing reactor 600, and the three-phase voltage source PWM forward converter 7 of the second embodiment are the filter 2, the zero-phase current suppressing reactor 6, the three-phase voltage It is configured similarly to the PWM inverter 1 except that the filter 200 is connected to the three-phase AC power supply 4 and the DC capacitor 77 of the three-phase voltage PWM forward converter 7 is connected in parallel to the DC load 8. ing.

Also in the second embodiment, the zero-phase current suppressing reactor 600 has the same function as that of the first embodiment, and therefore the same operation and effect as those of the first embodiment can be obtained. is there.

Embodiment 3 FIG. FIG. 3 shows a third embodiment of the present invention. As shown in FIG.
Converts a power converter into a three-phase voltage-type PWM forward converter 32 that converts three-phase AC power into DC power, and converts the DC power output from the three-phase voltage-type PWM forward converter 32 into the three-phase voltage. It is constituted by a three-phase voltage-type PWM converter 34 including a three-phase voltage-type PWM inverter 33 for converting into a three-phase AC power different from that provided by the type PWM forward converter 32. Also in the third embodiment, by providing the zero-phase current suppressing reactor 6 in each of the three-phase AC circuits, it is possible to reduce the zero-phase component of the current of the three-phase AC circuit in any of the three-phase AC circuits. it can.

In FIG. 3, the three-phase voltage-type PWM forward converter 32 includes a three-phase voltage-type PWM forward converter 7 and a filter 2.
The three-phase voltage source PWM forward converter 7 is connected to the three-phase AC power supply 4 via the filter 200 and the zero-phase current suppression reactor 600, and includes the zero-phase current suppression reactor 600. Is a three-phase voltage type PW
It is provided on the three-phase AC side of the M forward converter 7.

The three-phase voltage source PWM inverse converter 33
Comprises a three-phase voltage source PWM inverter 1, a filter 2, and a zero-phase current suppression reactor 6. These three-phase voltage source PWM inverter 1, filter 2, and zero-phase current suppression reactor 6 are shown in FIG. Is substantially the same as that of the first embodiment, except that the three-phase voltage type PWM inverter 1
It is connected to the three-phase voltage source PWM forward converter 7 of the WM forward converter 32 and is connected to the load 5 via the zero-phase current suppression reactor 6 and the filter 2. Here, the zero-phase current suppression reactor 6 is a three-phase voltage type PWM inverter 1
, And between the three-phase voltage source PWM inverter 1 and the fill 2.

In the third embodiment, the three-phase voltage source PW
The zero-phase current suppression reactor 6 of the M-inverting device 33 is provided between the three-phase voltage-type PWM inverter 1 and the filter 2, but as described at the end of the description of the first embodiment, As in the first embodiment, the same effect as when the zero-phase current suppression reactor 6 is provided between the filter 2 and the three-phase AC power supply 4 can be obtained. In the third embodiment, the same operation and effect as those of the above embodiments can be obtained.

Embodiment 4 In the above-described first to third embodiments, the power converter is a three-phase PWM control type and the three-phase AC side voltage is a pulse train having many harmonics. In the following fifth to ninth embodiments, a case is shown of a three-phase separately-excited power converter in which the three-phase AC side voltage of the power converter is basically a sine wave.

In the case of the three-phase separately-excited power converter, the three-phase AC side voltage is short-circuited at the start of commutation of the switch element, and is released from the short-circuit at the end of commutation.
For example, when the converter is a three-phase bridge connection, there are six commutations in one cycle, so that the line voltage of each phase undergoes 12 step changes in one cycle. Due to this sudden change in voltage, high-frequency leakage current flows through the three-phase AC circuit and the ground via the ground capacitance of the power conversion device and the ground capacitance of the three-phase AC circuit, and the zero-phase component of the leakage current causes induction disturbance. This is the same as the phase voltage type PWM control converter.

In the fourth embodiment, a zero-phase current suppression reactor is used in the case where the power converter is a three-phase separately-excited uncontrolled power forward converter composed of a three-phase diode rectifier.

FIG. 4 shows the fourth embodiment. In FIG. 4, a three-phase separately-excited non-controlled current source power forward converter 3001 of the fourth embodiment includes a diode rectifier 1000 as a three-phase separately-excited non-controlled current source power forward converter, a filter 2000, and a zero-phase It is composed of a current suppression reactor 6 and a DC reactor 1017.

The diode rectifier 1000 includes three pairs of switch elements 1011, 1014;
012, 1015; 1013, 1016 connected in parallel with each other,
14; 1012, 1015; 1013, and 1016 are connected in series in the forward direction, and their midpoints are connected to the three-phase AC power supply 4 via the filter 2000 and the zero-phase current suppression reactor 6, respectively. In addition, each pair of switch elements 1011 and 1014;
5; 1013 and 1016 are connected in parallel to the resistor 8 via the DC reactor 1017.

Filter 2000 includes three pairs of capacitors 20 connected in parallel to three-phase three wires connecting zero-phase current suppression reactor 6 and diode rectifier 1000, respectively.
01 to 2003 and reactors 2004 to 2006, each pair of capacitors 2001 to 2003 and reactors 2004 to 2006 are connected in series with each other, and one ends of the reactors 2004 to 2006 are connected to each other.

The zero-phase current suppressing reactor 6 includes a common magnetic core 64 and a three-phase coil 6 wound around the common magnetic core 64, similarly to the first embodiment shown in FIG.
1, 62, 63, and each three-phase coil 61, 6
One end of each of 2 and 63 is connected to the three-phase AC power supply 4, and the other end is connected to the diode rectifier 1000 via the filter 2000.

Also in the fourth embodiment, the zero-phase current suppressing reactor 6 operates in substantially the same manner as in the first to third embodiments, and has the same effect.

Embodiment 5 FIG. FIG. 5 shows a fifth embodiment of the present invention, which is the fourth embodiment.
Is a three-phase separately excited current type reversible power converter using a thyristor rectifier 1100 instead of the diode rectifier 1000 in FIG.

The power converter according to the fifth embodiment includes a three-phase separately-excited reversible power converter 3002. In FIG. 5, the thyristor rectifier 1100 includes three pairs of switch elements 1111 to 1116 composed of thyristors, that is, the diode rectifier 1 of the fourth embodiment.
000 switch elements 1111 to 1116 are replaced with thyristors. In the fifth embodiment, a thyristor rectifier 1100, a DC reactor 1017, a filter 2000, and a zero-phase current suppression reactor 6 constitute a three-phase separately excited current type reversible power converter 3002 as a power converter. In the fifth embodiment, the same function and effect as those of the above embodiments can be obtained.

Embodiment 6 FIG. FIG. 6 shows a sixth embodiment of the present invention, in which the power converter is constituted by a three-phase separately-excited non-control voltage-type power forward converter 3003.

The sixth embodiment is different from the fourth embodiment shown in FIG. 4 in that each pair of switch elements 1011, 1014;
A DC capacitor 1018 is connected in parallel to 012, 1015; 1013, 1016, and the other configuration is the same as that of the fourth embodiment. In the sixth embodiment, the diode rectifier 1000 and the DC reactor 101
7, the DC capacitor 1018, the filter 2000, and the zero-phase current suppression reactor 6 constitute a three-phase separately-excited uncontrolled voltage-type power forward converter 3003. In the sixth embodiment, the same operation and effect as those of the above embodiments can be obtained.

Embodiment 7 FIG. 7 shows a seventh embodiment of the present invention, in which the power converter is constituted by a three-phase separately-excitable controllable non-reciprocal power forward converter 3004.

The seventh embodiment is different from the fifth embodiment shown in FIG. 5 in that each pair of switch elements 1111, 1114; 1 composed of thyristors connected in series to each other.
A DC capacitor 1018 is connected in parallel to 112, 1115; 1113, 1116, and the other configuration is the same as that of the fifth embodiment. In the seventh embodiment, a thyristor rectifier 1100, a DC reactor 101
7, the DC capacitor 1018, the filter 2000, and the zero-phase current suppression reactor 6 constitute a three-phase separately-excitable controllable non-reciprocal power conversion device 3004. In the seventh embodiment, the same functions and effects as those of the above embodiments can be obtained.

Embodiment 8 FIG. FIG. 8 shows an eighth embodiment of the present invention, in which the power converter is constituted by a three-phase separately excited voltage type reversible power converter 3005.

The eighth embodiment is different from the seventh embodiment in FIG.
, The thyristor rectifier 1100 is replaced with a reversible thyristor rectifier 1200. The reversible thyristor rectifier 1200 includes a pair of switch elements 1211, 1214;
212, 1215; 1213, 1216, each pair of switch elements 1 composed of thyristors connected in series with each other.
217, 1218; 1219, 1220; 1221, 1
222 is connected in parallel with the polarity reversed, and each pair of switch elements 1217, 1218; 1219, 1220;
1, 1222 are the intermediate points of the corresponding pairs of switch elements 1211, 1214; 1212, 1215;
The other components are the same as those of the seventh embodiment in FIG. 7. In the eighth embodiment, a reversible thyristor rectifier 1200, a DC reactor 1017, a DC capacitor 1018, a filter 20
The three-phase separately excited voltage type reversible power converter 3005 is constituted by 00 and the zero-phase current suppression reactor 6. In the eighth embodiment, the same operation and effect as those of the above embodiments can be obtained.

Embodiment 9 FIG. FIG. 9 shows a ninth embodiment of the present invention. In the ninth embodiment, a power converter is a combination of a three-phase separately-excited reversible power forward converter 3002 and a three-phase separately-excited reversible power inverse converter 3006. And a three-phase separately-excited power converter 3007.

Referring to FIG. 9, a three-phase separately-excited reversible power forward converter 3002 has substantially the same configuration as that of the fifth embodiment shown in FIG. 5, that is, a zero-phase current suppression reactor 6, a filter 2000, a thyristor It is composed of a rectifier 1100 and a DC reactor 1017.

A three-phase separately-excited reversible power inverter 300
6 is a thyristor inverse converter 1300 connected to the thyristor rectifier 1100 via the DC reactor 1017
A filter 2300 connected to the three-phase AC side of the thyristor inverter 1300, and a filter 2300 at one end.
And a three-phase AC power source or a three-phase back electromotive force load 4 whose other end is a commutation voltage source of the thyristor inverter 1300.
000 connected to the zero-phase current suppression reactor 6000.

The thyristor inverse converter 1300 includes switch elements 1301, 1304; 1302, 1305; 1303, each of which comprises three pairs of thyristors connected in series with each other.
1306, each pair of switch elements 1301, 13
04; 1302, 1305; 1303, 1306 are switch elements 1111 of each pair of the thyristor rectifier 1100,
1114; 1112, 1115; 1113, 1116 are connected in parallel with the polarity reversed.

The filter 2300 and the zero-phase current suppression reactor 6000 include a three-phase separately-excited reversible power forward converter 3002
Filter 2000 and zero-phase current suppression reactor 6, that is, filter 2300 comprises three pairs of capacitors and reactor 2 connected in series with each other.
301, 2304; 2302, 2305; 2303, 2
306, the zero-phase current suppression reactor 6000
It comprises three three-phase coils 6061, 6063, 6063 and a common magnetic core 6064. Embodiment 9
However, the same operation and effect as those of the above embodiments can be obtained.

[0076]

As described above, according to the present invention, almost no reactance is exhibited with respect to the positive-phase component and the negative-phase component in the three-phase AC input current or the three-phase AC output current of the power converter, and the reactance is zero. With a zero-phase current suppression reactor configured to exhibit sufficient reactance for the phase components, the magnetic flux due to the three-phase positive and negative phase currents is zero, and therefore for these currents The reactance is zero, and the magnetic flux due to the zero-phase current of each of the three-phase currents is mutually added to the zero-phase current, thereby exhibiting a large reactance, thereby effectively reducing the zero-phase current. Therefore, without affecting the three-phase AC fundamental current originally required for the power converter,
It is possible to reduce a zero-phase component, which is a major cause of interference with the communication line.

The zero-phase current suppression reactor includes:
Each of the three-phase windings needs a current capacity capable of passing the fundamental wave current, but the core used as the common core only needs to be one that does not saturate with respect to the zero-phase current. Since it is sufficiently small, the zero-phase current suppressing reactor can be manufactured in a small size and economically.

[Brief description of the drawings]

FIG. 1A is a circuit diagram showing Embodiment 1 of the present invention, and FIG. 1B is a configuration example of a zero-phase current suppressing reactor used in Embodiments 1 to 9 of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a third embodiment of the present invention.

FIG. 4 is a circuit diagram showing a fourth embodiment of the present invention.

FIG. 5 is a circuit diagram showing a fifth embodiment of the present invention.

FIG. 6 is a circuit diagram showing a sixth embodiment of the present invention.

FIG. 7 is a circuit diagram showing a seventh embodiment of the present invention.

FIG. 8 is a circuit diagram showing an eighth embodiment of the present invention.

FIG. 9 is a circuit diagram showing a ninth embodiment of the present invention.

10A is a circuit diagram showing a conventional example, and FIG. 10B is a waveform diagram for one phase of a three-phase AC line voltage and a line current in the conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Three-phase voltage type PWM inverter, 2 filters, 3 three-phase voltage type PWM inverter, 4 three-phase AC power supply, 5 load, 6 zero-phase current suppression reactor, 7 three-phase voltage type PWM
M forward converter, 8 DC load, 11-16 switch element, 17 DC capacitor, 21-26 reactor,
27 to 29 capacitors, 30 three-phase voltage type PWM inverter, 32 three-phase voltage type PWM forward converter, 33 three-phase voltage type PWM inverter, 34 three-phase voltage type PWM converter, 61, 62, 63 three Phase coil, 64 common core, 200 filter of voltage source PWM forward converter 7, 29
1-293 resistance, 600 zero-phase current suppression reactor,
1000 Diode rectifier, 1002 Ground capacitance of three-phase AC circuit, 1017 DC reactor, 1
018 DC capacitor, 1100 thyristor rectifier, 1200 reversible thyristor rectifier, 1300 thyristor reverse converter, 2000 filter, 2300 filter, 3001 current-type power forward converter, 3002 three-phase separately excited current-type reversible power converter, 3003 three-phase separately excited Uncontrolled voltage-type power forward converter, 3004 three-phase separately-excitable control voltage-type nonreciprocal power converter, 3005 three-phase separately-excited voltage-type reversible power converter, 3006 three-phase separately-excited reversible power inverse converter, 3007 three Phase-excited power converter, 4000 three-phase AC power source or three-phase counter-electromotive force load, 6000 zero-phase current suppression reactor.

Claims (21)

[Claims] 1. A power converter that exhibits little reactance with respect to a positive-phase component and a negative-phase component in a three-phase AC input current or a three-phase AC output current, and exhibits a sufficient reactance with respect to a zero-phase component. A power conversion device comprising a zero-phase current suppression reactor configured as described above. 2. A three-phase power converter is connected between a three-phase AC power supply and a load via a filter and a zero-phase current suppression reactor, wherein the zero-phase current suppression reactor is connected to a three-phase AC input current or a three-phase AC input current. A power conversion device characterized in that it exhibits almost no reactance with respect to a positive phase component and a negative phase component in a phase alternating current output current and exhibits sufficient reactance with respect to a zero phase component. 3. The power converter according to claim 1, wherein the zero-phase current suppression reactor is provided on a three-phase AC side. 4. The zero-phase current suppression reactor is formed by winding a three-phase coil around a common iron core so that the mutual magnetic coupling between the coils is dense and each coil has a sufficient reactance. The power converter according to any one of claims 1 to 3, wherein 5. The three-phase power converter is a three-phase voltage source PWM.
The power converter according to claim 2, comprising a forward converter. 6. The three-phase power converter is a three-phase voltage source PWM.
The power converter according to claim 2, comprising an inverter. 7. The three-phase power converter comprises a three-phase separately-excited uncontrolled current source forward converter.
The power converter according to any one of the preceding claims. 8. The three-phase separately excited uncontrolled current source forward converter includes a diode rectifier connected to the load, and a DC reactor connected in series between the diode rectifier and the load. The power converter according to claim 7, characterized in that: 9. The power converter according to claim 2, wherein the three-phase power converter comprises a three-phase separately-excited uncontrolled voltage source forward converter.
The power converter according to any one of the preceding claims. 10. The three-phase separately-excited uncontrolled voltage source forward converter includes a diode rectifier connected to the load, a DC reactor connected in series between the diode rectifier and the load, and the diode rectifier. The power converter according to claim 9, comprising a capacitor connected in parallel between the load and the load. 11. The power converter according to claim 2, wherein the three-phase power converter is constituted by a three-phase separately excited current type reversible converter. 12. The three-phase separately excited current type reversible converter includes a thyristor rectifier including a plurality of thyristors, and a DC reactor connected in series between the thyristor rectifier and the load. Claim 11
The power converter according to any one of the preceding claims. 13. The power conversion device according to claim 2, wherein said three-phase power converter comprises a three-phase separately-excitable controllable voltage-type irreversible forward converter. 14. The thyristor rectifier including a plurality of thyristors, wherein the three-phase separately-excitable controllable voltage-type irreversible forward converter includes:
14. The rectifier according to claim 13, comprising a DC reactor connected in series between the thyristor rectifier and the load, and a capacitor connected in parallel between the thyristor rectifier and the load. Power converter. 15. The power converter according to claim 2, wherein said three-phase power converter is constituted by a three-phase separately excited voltage type reversible converter. 16. A reversible thyristor rectifier including a plurality of thyristors connected in parallel with opposite polarities to each other and a three-phase separately excited voltage type reversible converter connected in series between the reversible thyristor rectifier and the load. 16. The power conversion device according to claim 15, wherein the power conversion device includes a DC reactor and a capacitor connected in parallel between the reversible thyristor rectifier and the load. 17. The first zero-phase current suppressing reactor is connected to a first zero-sequence current suppressing reactor.
A three-phase power forward converter provided on the three-phase AC side and a three-phase power reverse converter provided with a second zero-phase current suppression reactor on the second three-phase AC side; The second zero-phase current suppressing reactor exhibits little reactance with respect to the positive-phase component and the negative-phase component in the three-phase AC input current or the three-phase AC output current, and has a sufficient reactance with respect to the zero-phase component. A power converter characterized by being constituted to exhibit. 18. The three-phase power conversion device may be a three-phase PWM.
The three-phase power inverter is a three-phase P
The power converter according to claim 17, comprising a WM inverse converter. 19. The three-phase PWM forward converter includes a three-phase voltage-type PWM forward converter connected to a three-phase AC power supply via a first filter and the first zero-phase current suppression reactor, The three-phase voltage source PWM inverter includes a three-phase voltage source PWM inverter connected to a load via a second filter and the second zero-phase current suppression reactor, and the three-phase voltage source PWM. Forward converter and three-phase voltage source PWM
19. The power converter according to claim 18, wherein the inverters are connected to each other. 20. The three-phase power forward converter comprises a three-phase separately-excited reversible power forward converter, and the three-phase power inverter comprises a three-phase separately-excited reversible power inverse converter. Item 18. The power converter according to Item 17. 21. The three-phase separately excited reversible power forward converter,
A thyristor rectifier connected to a first three-phase AC power supply via a first filter and the first zero-phase current suppression reactor;
And a thyristor inverter connected to a second three-phase AC power supply or a three-phase back electromotive force load via the second zero-phase current suppression reactor, wherein the thyristor rectifier and the thyristor inverter are 21. The power supply device according to claim 20, wherein the power supply devices are connected to each other via a DC reactor.
The power converter according to any one of the preceding claims.