JP2007336766A - Matrix converter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a matrix converter device that reduces a common mode current flowing in a motor while reducing high-frequency noise to the power-supply side. <P>SOLUTION: The matrix converter device includes an input single-phase AC reactor 2, whose one end is connected to each phase of a three-phase AC power supply 1 and whose the other end is connected to the input side of a matrix converter main circuit 5, and a ground capacitor 3 whose one end is connected to the input side of the matrix converter main circuit 5 and whose the other end is grounded. The device also includes an input capacitor 4, whose one end is connected to the other end of the input single-phase AC reactor 2 and whose the other end is star-connected, an output three-phase AC reactor 6, whose one end is serially connected to the output side of the matrix converter main circuit 5, an output three-phase common mode choke coil 7, whose one end is serially connected to each phase of the other end of the output three-phase AC reactor 6 and whose the other end is connected to a load 9, and an output capacitor 8 whose one end is connected to the other end of the output three-phase common mode choke coil 7 and whose the other end is star-connected. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a matrix converter device having a filter circuit for reducing high-frequency noise generated by the switching operation of a power converter (direct AC / AC conversion without a DC intermediate circuit is also known as a PWM cycloconverter. Say).

  One of the problems on the input side of the power converter is conduction EMI (Electro Magnetic Interference). In order to solve this problem, a countermeasure has been conventionally taken by adding an input filter to the input side of the power converter. In the conventional technique of a general input filter, in order to reduce common mode noise flowing out to the power supply side, a method of increasing the inductance of the common mode choke of the input filter or a method of increasing the capacitance of the grounding capacitor can be mentioned. However, the method of increasing the inductance of the common mode choke is larger in size and expensive than the method of increasing the capacitance of the grounding capacitor. Further, although the method of increasing the capacitance of the grounding capacitor is small in size and inexpensive, the leakage current of the fundamental wave component flowing on the power supply side increases, and the danger to the human body such as electric shock increases.

  The prior art of the output filter of a power converter is demonstrated. Problems on the output side of the power converter include high frequency leakage current, conduction EMI, radiation EMI, electric corrosion of motor bearings, and surge voltage at motor terminals. In order to solve the above problems, conventionally, countermeasures have been taken by adding an output filter to the output side of the power converter. For example, Patent Documents 1 and 2 and Non-Patent Documents 1 and 2 are examples of output filters of conventional power converters. Patent Documents 1 and 2 and Non-Patent Document 1 are common mode filters for suppressing a common mode current. Non-Patent Document 2 is composed of a normal mode filter for suppressing the noise current in the normal mode and a common mode filter for suppressing the common mode current. Since the common mode filters represented by Patent Documents 1 and 2 and Non-Patent Document 1 have the resonance frequency of the filter for the common mode lower than the carrier frequency of the power converter, high-frequency leakage current, conduction EMI, radiation EMI Although problems caused by common mode voltage and common mode current such as electric corrosion of motor bearings can be effectively suppressed, surge voltage at the motor terminal cannot be suppressed.

  Further, the method represented by Non-Patent Document 2 has a filter cutoff frequency far higher than the carrier frequency of the power converter compared to the methods of Patent Documents 1 and 2, Non-Patent Document 1, and so on. Is small and inexpensive. In addition to high-frequency leakage current, conduction EMI, and radiation EMI, surge voltage at the motor terminal can be suppressed. However, in the method of Non-Patent Document 2, since the cut-off frequency of the common mode filter is much higher than the carrier frequency of the power converter, the electric corrosion of the motor bearing (the inside of the rotating bearing (ball bearing)) The phenomenon that the contact surface between the race and the rolling element is damaged due to the passage of slag, which is characterized by wavy wear) cannot be suppressed. In addition, none of the output filters alone can clear a standard related to suppression of conducted EMI (for example, European unified standards EN61800-3 C1, C2, etc.).

As described above, the conventional input filter reduces conduction EMI, which is one of the causes of malfunction of peripheral equipment, by bypassing it with a grounding capacitor. The danger to the human body etc. increases, and the problem that occurs on the output side of the power converter cannot be solved by itself. Moreover, although the problem which generate | occur | produces on the output side of a power converter device can be solved only by an output filter, conduction EMI cannot be reduced effectively.
JP 1998-107571 A Japanese Patent No. 3466118 IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL.28, NO.4, p858-p863, JULY / AUGUST 1992 IEEJ Transactions D, Vol.116, No.12, 1996, p1211-1219

Conventional power conversion devices take various measures in combination with a filter circuit. The input filter for reducing the conducted EMI increases the leakage current of the fundamental wave component and increases the risk of electric shock and the like to the human body, which alone can solve the problem that occurs on the output side of the power converter. Can not. Moreover, although the problem which generate | occur | produces on the output side of a power converter device can be solved only by an output filter, conduction EMI cannot be reduced effectively.
The present invention has been made in view of such a problem when a matrix converter is used in a power converter, and suppresses a surge voltage at a motor terminal, reduces high-frequency noise to the power supply side, and reduces the high-frequency noise to the motor. An object of the present invention is to provide a matrix converter device that reduces the common mode current that flows and minimizes the leakage current of the fundamental wave component that flows on the power supply side, and is totally safe and harmonized with the surrounding environment. Another object of the present invention is to reduce the size of the device by providing a common mode component suppressing effect to an input filter originally provided in a matrix converter.

In order to solve the above problem, the present invention is configured as follows.
The invention described in claim 1 includes an input single-phase AC reactor 2 having one end connected in series to each phase of the three-phase AC power source 1 and the other end connected to the input side of the matrix converter main circuit 5, and one end a matrix converter. In a matrix converter device including a grounding capacitor 3 connected to the input side of the main circuit 5 and grounded at the other end,
An input capacitor 4 having one end connected to the other end of the input single-phase AC reactor 2 and the other end star-connected, and one output connected in series to each phase on the output side of the matrix converter main circuit 5 A phase AC reactor 6, an output three-phase common mode choke coil 7 having one end connected in series to each other phase of the output three-phase AC reactor 6 and the other end connected to a load 9; And an output capacitor 8 connected to the other end of the phase common mode choke coil 7 and star-connected at the other end.
According to a second aspect of the present invention, in the first aspect, the input capacitor (4), the matrix converter main circuit (5), the output three-phase AC reactor (6), and the output capacitor ( 8), and the output three-phase AC reactor 6 is replaced with a single-phase AC reactor 10 for output.
According to a third aspect of the present invention, in the first or second aspect, the neutral point N1 of the input capacitor 4 and the neutral point N2 of the output capacitor 8 are connected.
According to a fourth aspect of the present invention, in the first or second aspect, the neutral point N1 of the input capacitor 4 and the neutral point N2 of the output capacitor 8 are connected via a circulating current suppressing portion (11). It is characterized by that.
According to a fifth aspect of the present invention, in the first or second aspect, the output three-phase AC reactor 6 or the output single-phase AC reactor 10 is removed, and one end is connected to the output side of the matrix converter main circuit 5. An output three-phase common mode choke coil 7 having the other end connected to a load 9 and a neutral point detector 12 is connected between the load side of the output three-phase common mode choke coil 7 and the output capacitor 8. It is characterized by this.
According to a sixth aspect of the present invention, in the fifth aspect, the neutral point detector 12 includes at least one of a transformer, a reactor, a capacitor, and a resistor having the same impedance for each phase. It is.

According to the present invention, the filter circuit configured on the input side and the output side of the matrix converter suppresses conduction EMI, and removes common mode component noise generated on the matrix converter output side due to the effect of the output side common mode filter. Therefore, it is possible to minimize the fundamental leakage current by minimizing the grounding capacitor of the input filter, and to achieve both reduction of conduction EMI and safety.
In addition, the input filter originally provided in the matrix converter can have a common mode component suppressing effect, and the apparatus can be miniaturized.
In addition, the input filter and the output filter can be easily connected, and a peripheral circuit optimum for the matrix converter can be configured.
Further, when it is not necessary to suppress the normal mode component on the matrix converter output side, the output filter can be configured with only the common mode filter, and the versatility of the power conversion device can be enhanced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a power converter according to the present invention. In the figure, 1 is a three-phase AC power source, 2 is an input single-phase AC reactor, 3 is a grounding capacitor, 4 is an input capacitor, 5 is a matrix converter main circuit, 6 is an output three-phase AC reactor, and 7 is an output. A three-phase common mode choke coil, 8 is an output capacitor, 9 is a load, N1 is a neutral point constituted by the input capacitor 4, and N2 is a neutral point constituted by the output capacitor 8. The output three-phase AC reactor 6 forms an AC reactor by applying insulated windings to a three-phase common iron core. Further, it is necessary to insert an LC filter that is a low-pass filter between the three-phase AC power supply 1 and the matrix converter main circuit 5.
In the figure, three input single-phase AC reactors 2 are connected in series between the three-phase AC power supply 1 and the matrix converter main circuit 5, and each phase is connected between the input single-phase AC reactor 2 and the matrix converter main circuit 5. The input capacitor 4 is connected to the ground capacitor 3 in a star connection (Y connection, star tangent). Further, between the matrix converter 5 and the load motor 9 (here, the motor is used, but the load is not limited to the motor), an output three-phase AC reactor 6 and an output three-phase are provided as output side filters. A common mode choke coil 7 is connected in series for each phase, a star-connected output capacitor 8 is connected between the output three-phase common mode choke coil 7 and the load motor 9, and the input capacitor 4 and the output capacitor 8 are connected. The neutral points (N1, N2) of the capacitor 8 are connected.
In FIG. 1, the normal mode filter for suppressing the normal mode component on the output side of the matrix converter includes an output three-phase AC reactor 6 and an output capacitor 8. The common mode filter for suppressing the common mode component on the output side of the matrix converter includes an output three-phase common mode choke coil 7 and an output capacitor 8.
The input filter is composed of an input single-phase AC reactor 2, a grounding capacitor 3, and an input capacitor 4 connected in a star shape, and a common-mode inductance can be obtained by using a single-phase AC reactor. In combination with 3, the effect of suppressing conduction EMI can be obtained. In addition, since this filter uses an input LC filter that is essentially a component of the matrix converter, it also serves as a power harmonic suppression effect.

  Moreover, FIG. 2 is a block diagram of the power converter device which shows a 2nd Example. The same names as those in FIG. 2 differs from FIG. 1 in that the output three-phase AC reactor 6 is replaced with three output single-phase AC reactors 10 divided into phases, and the other parts are the same as those in FIG. Unlike the three-phase AC reactor in which the single-phase AC reactor 10 for output is provided with a three-phase winding on the common iron core, the output single-phase AC reactor 10 naturally does not have interphase magnetic coupling.

Moreover, FIG. 3 is a block diagram of the power converter device which shows a 3rd Example.
The same names as those in FIG. 3 differs from FIG. 2 in that the circulating current suppression unit is provided between the neutral points N1 and N2, and the other parts are the same as those in FIG.
A circulating current reducing unit 11 for reducing the circulating current flowing through the input filter, the output filter, and the matrix converter main circuit 5 is provided as a part of the common mode filter. The circulating current reduction unit 11 at this time is a series circuit composed of passive elements such as a transformer, a reactor, a capacitor, and a resistor. The simplest example of the circulating current reduction unit 11 may be a resistor only. Since the circulating current is mainly caused by the unbalanced component of the three-phase power, the circulating current does not flow in an ideal state where the three-phase power is balanced.

FIG. 4 is a configuration diagram of a power conversion device showing a fourth embodiment.
The same names as those in FIG. 4 differs from FIG. 3 in that a neutral point detector 12 is provided between the load side of the output three-phase common mode choke coil 7 and the output capacitor 8, and the other parts are the same as those in FIG. Is the same.
In a motor drive system or the like, when the motor cable is sufficiently short, the normal mode filter on the output side of the matrix converter is not necessary, and only the common mode filter is used by using the neutral point detector 12 as shown in FIG. Can be configured. The neutral point detection unit 12 includes a passive element such as a transformer, a reactor, a capacitor, and a resistor having the same impedance for each phase, or a combination thereof. The neutral point detecting means 12 is connected in series with the other end of the output capacitor 8 whose one end is Y-connected.

  The difference between the present invention and the prior art is that the input filter and the output filter can be integrated to minimize the ground capacitor of the input filter by taking advantage of the common mode filter that is a component of the output filter. In the filter, the AC reactor of the input LC filter originally required for the matrix converter is changed to three single-phase AC reactors, so that the function of suppressing conduction EMI is provided in combination with the grounding capacitor.

  The power conversion device of the present invention can be applied not only to a motor drive system but also to a distributed power supply device that uses a generator and is connected to a power source.

The block diagram of the power converter device which shows 1st Example of this invention The block diagram of the power converter device which shows 2nd Example of this invention The block diagram of the power converter device which shows 3rd Example of this invention The block diagram of the power converter device which shows 4th Example of this invention

Explanation of symbols

1 Three-phase AC power supply 2 Input single-phase AC reactor 3 Grounding capacitor 4 Input capacitor 5 Matrix converter main circuit 6 Output three-phase AC reactor 7 Output three-phase common mode choke coil 8 Output capacitor 9 Load 10 Output single Phase AC reactor 11 Circulating current suppression unit 12 Neutral point detection unit N1, N2 Neutral point

Claims (6)

An input single-phase AC reactor (2) having one end connected in series to each phase of the three-phase AC power source (1) and the other end connected to the input side of the matrix converter main circuit (5), and one end being a matrix converter main circuit In a matrix converter device including a grounding capacitor (3) connected to the input side of (5) and grounded at the other end,
An input capacitor (4) having one end connected to the other end of the input single-phase AC reactor (2) and the other end star-connected, and one end in series with each phase on the output side of the matrix converter main circuit (5) Connected three-phase AC reactor for output (6) and three-phase common for output with one end connected in series to each other phase of the three-phase AC reactor for output (6) and the other end connected to a load (9) A matrix comprising a mode choke coil (7) and an output capacitor (8) having one end connected to the other end of the output three-phase common mode choke coil (7) and the other end star-connected. Converter device.   The input capacitor (4), the matrix converter main circuit (5), the output three-phase AC reactor (6), and the output capacitor (8), the output three-phase AC reactor (6 The matrix converter device according to claim 1, wherein a single-phase AC reactor for output (10) is replaced.   3. The matrix converter device according to claim 1, wherein a neutral point (N1) of the input capacitor (4) is connected to a neutral point (N2) of the output capacitor (8).   The neutral point (N1) of the input capacitor (4) and the neutral point (N2) of the output capacitor (8) are connected via a circulating current suppressing part (11). 3. The matrix converter device according to 1 or 2.   The output three-phase AC reactor (6) or the output single-phase AC reactor (10) was removed, one end was connected to the output side of the matrix converter main circuit (5), and the other end was connected to the load (9). A neutral point detector (12) is connected between the output three-phase common mode choke coil (7) and the load side of the output three-phase common mode choke coil (7) and the output capacitor (8). The matrix converter device according to claim 1 or 2, wherein   6. The matrix converter device according to claim 5, wherein the neutral point detector (12) includes at least one of a transformer, a reactor, a capacitor, and a resistor having the same impedance for each phase.

Images