JP4209100B2 - Noise reduction device for power converter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a noise reduction device for a power conversion device that converts supply power from a power source into AC power and supplies the load to a load, and more particularly to a noise reduction device for a power conversion device that suppresses conductive electromagnetic interference to the supply power source side. It is about.
[0002]
[Prior art]
FIG. 8 is a circuit configuration diagram showing a conductive noise measuring apparatus using a conventional power converter.
In FIG. 8, 1 is an AC power source having a three-phase (R, S, T phase) power supply line, and 2 is a ground point from the AC power source 1 to the ground.
[0003]
Reference numeral 4 denotes a power converter connected to the AC power source 1 via a power supply line, and reference numeral 5 denotes a load to which converted power from the power converter 4 is supplied.
The power converter 4 includes an AC / DC converter 13, a capacitor 14, and a DC / AC converter 15.
[0004]
The AC / DC converter 13 converts an AC voltage into a DC voltage, the capacitor 14 accumulates and smoothes the DC voltage, and the DC / AC converter 15 converts the DC voltage into an AC voltage and outputs it to the load 5.
[0005]
16 is a pseudo power supply network inserted in the power supply line from the AC power supply 1 to the power converter 4, and includes three-phase input terminals R, S, T, three-phase output terminals U, V, W, It has a ground terminal G to the ground point 2 and is configured to measure the conductive noise generated by the power converter 4.
[0006]
In general, the power conversion device 4 includes noise (that is, normal mode noise) including high-frequency current flowing between the output terminals U, V, and W of the pseudo power supply network 16 inserted on the input side, a power supply line, and a ground point. 2 (ie, common mode noise) due to high-frequency current flowing through a floating capacitance (not shown) existing between the two (ground line). These noises are measured by the pseudo power supply network 16.
[0007]
FIG. 9 is a circuit configuration diagram schematically showing a general pseudo power supply network 16.
In FIG. 9, reference numerals 100 to 102 denote reactors that are inserted between the input terminals R, S, and T from the AC power source 1 and the output terminals U, V, and W to the load 5, respectively.
[0008]
Reference numerals 103 to 105 denote capacitors connected to the output terminals U, V, and W. Reference numerals 106 to 108 denote resistors that are connected to the capacitors 103 to 105 to form a series circuit. Each series circuit is an output terminal. Inserted between U, V, W and the ground terminal G to the ground point 2.
[0009]
Next, the noise quantitative evaluation operation using the pseudo power supply network 16 configured as shown in FIG. 9 will be described with reference to FIGS. 10 and 11.
FIG. 10 is an explanatory diagram showing a noise path flowing in a normal mode with respect to a general pseudo power supply network 16, and FIG. 11 is an explanatory diagram showing a noise path flowing in a common mode with respect to the pseudo power supply network 16.
[0010]
In FIG. 10, when the noise in the normal mode generated by the power conversion device 4 is between the U and V phases, a high-frequency current flows through the thick arrow path.
At this time, since the voltage V6 is generated in the resistor 106, the noise can be quantitatively evaluated by measuring the voltage V6 across the resistor 106.
[0011]
Further, in FIG. 11, high-frequency current flows through the thick arrow path due to noise in the common mode generated by the power conversion device 4.
Also in this case, since the voltage V6 is generated in the resistor 106, noise can be quantitatively evaluated by measuring the voltage V6.
[0012]
In general, the voltage V6 of the resistor 106 to be measured is measured by superimposing noise in both the normal mode and the common mode.
Conventionally, for example, an LC filter is used in order to reduce noise generated by the power conversion device 4 and the like as described above.
[0013]
FIG. 12 is a circuit configuration diagram showing a noise reduction device of a conventional power conversion device using an LC filter, and shows a state where the LC filter is inserted between the AC power supply 1 and the power conversion device 4.
[0014]
In FIG. 12, reference numerals 110 to 112 denote common mode reactors inserted on the input terminals R, S, and T sides, and reference numerals 116 to 118 denote capacitors inserted between one end of each common mode reactor 110 to 112 and the ground terminal G. is there.
Common mode reactors 110-112 and capacitors 116-118 constitute a common mode noise filter.
[0015]
113 to 115 are reactors inserted on the output terminals U, V, and W sides, and 119 to 121 are capacitors inserted between the two phases of the output terminals U, V, and W.
Reactors 113 to 115 and capacitors 119 to 121 constitute a normal mode noise filter.
[0016]
However, in the conventional apparatus shown in FIG. 12, the current supplied to power converter 4 flows to common mode reactors 110 to 112 and reactors 113 to 115, so that each reactor becomes larger and normal mode and common mode Since these two measures need to be taken individually, the LC filter becomes large.
[0017]
On the other hand, as another conventional example of the noise reduction device, for example, “Common of large-capacity PWM inverters” described on pages 63 to 68 of the semiconductor power conversion study group document (SPC-98-43) published in January 1998 is described. "Mode voltage active compensation circuit".
[0018]
FIG. 13 is a circuit configuration diagram schematically showing a noise reduction device of a conventional power conversion device described in the above document.
In FIG. 13, reference numeral 130 denotes a voltage detection circuit connected to the output terminal of the power conversion device 4, which detects common mode voltage fluctuations generated on the output side by the power conversion device 4.
[0019]
Reference numeral 131 denotes a high-pass filter connected to the output terminal of the voltage detection circuit 130, and 132 and 133 denote parallel transistors connected to the output terminal of the high-pass filter 131.
[0020]
Reference numerals 134 to 137 denote common mode reactors inserted into the three-phase input terminal of the load 5 and the output terminals of the transistors 132 and 133, respectively.
Reference numerals 34 and 35 denote DC power sources for driving the transistors 132 and 133, which are connected to a connection point between the common mode reactor 137 and the ground.
[0021]
The voltage detection circuit 130 detects a common mode voltage fluctuation that causes common mode noise, and the high-pass filter 131 extracts only a high-frequency component of the voltage fluctuation.
[0022]
The transistors 132 and 133 and the common mode reactors 134 to 137 constitute a common mode voltage application circuit for the load 5, and apply a voltage to the load 5 that has an opposite phase to the voltage fluctuation in the common mode.
Thereby, the common mode voltage fluctuation which generate | occur | produces via the load 5 is suppressed, and a common mode noise is suppressed.
[0023]
However, also in the conventional device shown in FIG. 13, the current supplied by the power conversion device 4 flows to the common mode reactors 134 to 137, so that each reactor becomes large.
[0024]
Moreover, since the noise mode to be reduced is only the common mode, normal mode noise cannot be reduced, and a filter for reducing normal mode noise must be inserted separately.
[0025]
[Problems to be solved by the invention]
As described above, the noise reduction device of the conventional power conversion device has the problem that, in the device shown in FIG. 12, the common mode reactors 110 to 112 and the reactors 113 to 115 become large, and the LC filter becomes large. There was a point.
[0026]
Further, the conventional apparatus shown in FIG. 13 has a problem that each of the common mode reactors 134 to 137 is increased and a filter for reducing normal mode noise has to be inserted separately.
[0027]
The present invention has been made to solve the above-described problems, and is configured so that the supply current of the power conversion device does not flow to the noise reduction filter, thereby realizing a power conversion that achieves a reduction in size of the filter. It aims at obtaining the noise reduction apparatus of an apparatus.
[0028]
It is another object of the present invention to obtain a noise reduction device for a power conversion device that can simultaneously reduce both normal mode noise and common mode noise.
[0029]
[Means for Solving the Problems]
A noise reduction device for a power conversion device according to the present invention is a noise reduction device for a power conversion device that is connected to a power supply via a plurality of power supply lines and supplies converted power to a load, and each power supply line And a capacitance detection element that detects a voltage of the capacitance element, and a control current corresponding to the voltage of the capacitance element is supplied to each power supply line side. Control means, and the control means suppresses the high-frequency voltage component existing in the capacitance element by the control current.
[0030]
A noise reduction device for a power conversion device according to the present invention includes an impedance circuit inserted between each power supply line and a ground line, the capacitance element includes a first capacitor, and the impedance circuit includes: The control means supplies a control current to the connection point between the second capacitor and the resistor in accordance with the voltage of the first capacitor.
[0031]
The noise reduction device for a power conversion device according to the present invention includes a series circuit including a capacitor and a resistor inserted between each power supply line and a ground line, and the capacitance element includes each power supply line. The control means supplies a control current to the connection point between the capacitor and the resistor in accordance with the voltage of the stray capacitance.
[0032]
Moreover, the electrostatic capacitance element by the noise reduction device of the power conversion device according to the present invention comprises a capacitor, and the control means directly supplies a control current to each power supply line according to the voltage of the capacitor.
[0033]
Further, the electrostatic capacitance element by the noise reduction device of the power conversion device according to the present invention comprises a stray capacitance between each power supply line and the ground line, and the control means controls the control current according to the voltage of the stray capacitance. Is directly supplied to each power supply line.
[0034]
Further, the control means by the noise reduction device of the power conversion device according to the present invention includes a high-pass filter, a subtracter, an arithmetic controller and a current generator, and the high-pass filter converts a high-frequency component included in the output signal of the voltage detection circuit. The subtractor subtracts the output signal of the high-pass filter from the zero signal, the arithmetic controller calculates a current command value based on the output signal of the subtractor, and the current generator responds to the current command value. The current value is output as a control current.
[0035]
The noise reduction device of the power conversion device according to the present invention includes an impedance element inserted between a connection point between each power supply line and the capacitance element and the power source, and the impedance element includes a voltage of the power source. And a voltage difference between the capacitance element and the capacitance element is applied.
[0036]
Moreover, the impedance element by the noise reduction apparatus of the power converter device which concerns on this invention consists of a reactor.
[0037]
Moreover, the power supply by the noise reduction apparatus of the power converter device which concerns on this invention consists of AC power supply.
[0038]
Moreover, the power source by the noise reduction device of the power converter according to the present invention is a DC power source.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing the first embodiment of the present invention. The same components as those described above (see FIG. 8) are denoted by the same reference numerals and detailed description thereof is omitted.
[0040]
In FIG. 1, reference numeral 3 denotes a first capacitor (hereinafter simply referred to as “capacitor”), which is inserted between each power supply line of the AC power supply 1 and a ground line connected to the ground point 2. Here, in order to avoid complexity, the capacitor 3 is shown for only one phase.
[0041]
Reference numeral 6 denotes a second capacitor (hereinafter simply referred to as “capacitor”) inserted between each power supply line and the grounding point 2 (grounding line). Like the capacitor 3, only one phase is shown. ing.
[0042]
A resistor 7 is inserted between one end of the capacitor 6 and the grounding point 2, and constitutes a series circuit together with the capacitor 3.
A voltage detection circuit 8 detects the voltage V3 of the capacitor 3.
[0043]
9 is a high-pass filter that passes a high-frequency component of the detected voltage V3 of the capacitor 3, 10 is a subtractor that subtracts the output signal V9 of the high-pass filter 9 from the zero signal, and 11 is a current based on the output signal of the subtractor 10. An arithmetic controller 12 that calculates a command value Icom *, and 12 is a current generator that outputs a current value Icom corresponding to the current command value Icom * as a control current.
[0044]
The high-pass filter 9, the subtractor 10, the arithmetic controller 11, and the current generator 12 constitute control means for supplying a control current Icom corresponding to the voltage of the capacitor 3 to each power supply line side.
In this case, the control current Icom is supplied to the connection point between the capacitor 6 and the resistor 7.
[0045]
Here, only the circuit elements for one phase of the control means corresponding to each phase (three phases) are shown, but the other two phases have the same configuration, and are not shown. Yes.
[0046]
FIG. 2 is a circuit configuration diagram showing in detail the control means (high-pass filter 9, subtractor 10, arithmetic controller 11 and current generator 12) according to Embodiment 1 of the present invention. In FIG. 2, 20 is a capacitor inserted in the input terminal, 21 is a resistor inserted between the capacitor 20 and the ground point 2, and these constitute a high-pass filter 9 comprising a CR time constant circuit. .
[0047]
Reference numeral 22 denotes a resistor connected to one end of the capacitor 20, and reference numeral 23 denotes a resistor connected to one end of the resistor 22.
Reference numeral 24 denotes an operational amplifier constituting the subtractor 10 and the operation controller 11 in association with the resistors 22 and 23. One end of the resistor 22 is used as an inverting input, and the resistor 23 is used as a feedback resistor to the inverting input terminal. .
[0048]
Reference numerals 25, 26, 28, 29, and 33 denote resistors, reference numerals 27 and 30 denote operational amplifiers associated with the respective resistors 25, 26, 28, and 29, reference numerals 31 and 32 denote parallel transistors connected to an output terminal of the operational amplifier 27, and reference numerals 34 and 34. , 35 are direct current power sources for driving the transistors 31 and 32, and these constitute the current generator 12.
[0049]
The resistor 25 is inserted between the ground point 2 and the inverting input terminal of the operational amplifier 27, and the resistor 26 is inserted between the output terminal of the operational amplifier 24 and the non-inverting input terminal of the operational amplifier 27.
[0050]
The resistor 28 is inserted between the output terminal of the operational amplifier 30 and the non-inverting input terminal of the operational amplifier 27, and the resistor 29 is inserted between the output terminals of the transistors 31 and 32 and the inverting input terminal of the operational amplifier 27. Yes.
[0051]
The resistor 33 is inserted between the output terminals of the transistors 31 and 32 and the non-inverting input terminal of the operational amplifier 30, and one end of the resistor 33 is an output terminal of the current generator 12.
[0052]
The current generator 12 shown in FIG. 2 has the same configuration as described on pages 76 to 77 of the “Analog IC Utilization Handbook” (CQ Publisher) issued on January 1, 1987, for example. Is omitted.
[0053]
Next, the operation according to the first embodiment of the present invention shown in FIG. 1 will be described.
First, the AC / DC converter 13 in the power converter 4 obtains AC power from the AC power source 1 and converts it to DC power, and the capacitor 14 stores the converted DC power.
[0054]
The DC power stored in the capacitor 14 is converted into arbitrary AC power by the DC / AC converter 15 and drives the load 5.
In such a power conversion process, it is known that the power conversion device 4 performs high-frequency switching, and conductive noise generated along with the switching is transmitted via a ground line or a power supply line connected to the ground point 2. Appears in the AC power supply 1.
[0055]
Therefore, the capacitor 3 connected to each power supply line of the AC power source 1 reduces the conductive noise to the AC power source 1 by bypassing the high-frequency current that causes the conductive noise.
[0056]
The pseudo power supply network 16 inserted between the power converter 4 and the AC power supply 1 is a device that measures conductive noise generated in the AC power supply 1 as described above.
Note that the pseudo power supply network 16 is removed when the power conversion device 4 is put into actual operation without measuring the conductive noise.
[0057]
In FIG. 1, conductive noise is caused by a high frequency voltage generated by the capacitor 3.
Therefore, the control means injects a high-frequency control current Icom into the capacitor 3 via the capacitor 6 and suppresses the high-frequency voltage generated by the capacitor 3.
[0058]
Specifically, the voltage detection circuit 8 detects the voltage V3 of the capacitor 3, the high-pass filter 9 extracts the high-frequency voltage component V9, and in order to make the extracted high-frequency voltage component V9 zero, it matches the zero voltage command. Then, the arithmetic controller 11 is operated.
[0059]
That is, the arithmetic controller 11 inputs a current command Icom * for setting the high-frequency voltage component V9 to zero to the current generator 12, and the current generator 12 outputs a control current Icom that matches the current command Icom *. .
[0060]
At this time, since the control current Icom flowing into the connection point between the capacitor 6 and the resistor 7 is only a high-frequency component, most of the current flows into the power supply line via the capacitor 6 and consequently flows into the capacitor 3.
[0061]
In this way, the control current Icom acts to make the high frequency voltage appearing in the capacitor 3 zero, thereby suppressing the conductive noise measured by the pseudo power supply network 16.
[0062]
Next, the conductive noise suppression operation according to the first embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a waveform diagram showing waveforms of the voltage V3 of the capacitor 3, the output voltage V9 of the high-pass filter 9, and the current command value Icom *.
[0063]
In FIG. 3, the voltage V <b> 3 of the capacitor 3 has a waveform in which a high-frequency voltage is superimposed on the output voltage of the AC power supply 1.
Note that the frequency of the AC power supply 1 is considerably lower than the noise frequency composed of the harmonic voltage. Therefore, if the noise frequency is enlarged so that the noise frequency can be recognized, it can be approximated to a DC voltage.
[0064]
Therefore, as shown in FIG. 3, the voltage V3 of the capacitor 3 can be shown in a simplified manner so that a noise frequency (harmonic voltage) is superimposed on the DC voltage A.
The output voltage V9 of the high pass filter 9 has a waveform obtained by extracting the high frequency component of the voltage V3 of the capacitor 3.
[0065]
The arithmetic controller 11 performs feedback control for setting the output voltage V9 of the high-pass filter 9 to zero, and outputs a current command value Icom * in which the polarity of the output voltage V9 is inverted.
[0066]
Hereinafter, as described above, the current generator 12 performs the feedback control by actually injecting the control current Icom corresponding to the current command value Icom * into the connection point of the series circuit, so that the high-frequency component of the voltage V3 of the capacitor 3 is controlled. To suppress.
[0067]
In this way, by suppressing the high frequency component of the voltage V3 of the capacitor 3 and reducing noise without distinguishing between the normal mode and the common mode, the conductivity generated by the power converter 4 and detected by the pseudo power supply network 16 is detected. Noise can be suppressed.
[0068]
Further, by controlling only the high-frequency voltage of the voltage V3 of the capacitor 3 as a control target, the control current Icom from the current generator 12 is set to a low current output, that is, the capacitances of the transistors 31 and 32 in the current generator 12 are reduced. And cost reduction can be realized.
[0069]
Further, by injecting the control current Icom into the connection point between the capacitor 6 and the resistor 7, most of the low frequency component due to the AC power supply 1 existing in the capacitor 3 appears in the capacitor 6, and only the high frequency voltage appears in the resistor 7. Appears.
[0070]
Therefore, the voltage applied to the current generator 12 is only a high-frequency voltage, and a low-frequency component (fundamental wave component) having a large amplitude that the AC power supply 1 has is not applied to the current generator 12. The breakdown voltage of 12, that is, the voltage of the DC power supplies 34 and 35 and the breakdown voltage of the transistors 31 and 32 can be set low.
[0071]
Embodiment 2. FIG.
In the first embodiment, the control current Icom is supplied to the connection point between the capacitor 6 and the resistor 7. However, the control current Icoma may be directly supplied to each power supply line.
[0072]
FIG. 4 is a circuit configuration diagram showing Embodiment 2 of the present invention. The same components as those described above (see FIG. 1) are denoted by the same reference numerals, or “a” after the reference numerals. Detailed description is omitted.
[0073]
In FIG. 4, the difference from the first embodiment is that the control current Icoma output from the current generator 12a is directly supplied to each power supply line, and the output terminal of the current generator 12a is connected to the pseudo power supply network 16. It is connected to the alternating current power supply 1 via.
[0074]
In this case, if the withstand voltage of the transistors 31 and 32 (see FIG. 2) is set large in the current generator 12a and the voltage of the DC power supplies 34 and 35 is set high, the current generator 12a as shown in FIG. Can be directly connected to the AC power source 1.
[0075]
In this way, by directly connecting the output terminal of the current generator 12a to the AC power source 1, the series circuit (capacitor 6 and resistor 7) shown in FIG. 1 can be omitted, thus further reducing the cost. Can be realized.
[0076]
Embodiment 3 FIG.
In the first and second embodiments, the capacitor 3 is inserted between each power supply line and the ground point 2 (ground line). However, instead of the capacitor 3, between each power supply line and the ground line. Alternatively, the stray capacitance CF may be used.
[0077]
FIG. 5 is a circuit configuration diagram schematically showing Embodiment 3 of the present invention. Components similar to those described above (see FIG. 1) are denoted by the same reference numerals, or suffixed with “b”. Detailed description will be omitted.
[0078]
In FIG. 5, the difference from the first embodiment is that the capacitor 3 is omitted, and a voltage detection circuit is provided between each power supply line of the AC power supply 1 and the ground point 2 (ground line). 8 is directly connected.
[0079]
In this case, the control means causes the control current Icomb to flow through each power supply line in accordance with the stray capacitance voltage VF from the voltage detection circuit 8 and exists in the stray capacitance CF between each power supply line and the ground line 2. The high frequency voltage component is zero.
[0080]
As shown in FIG. 5, when the stray capacitance CF exists between the pseudo power supply network 16 (or the AC power supply 1) and the ground point 2, the stray capacitance CF can be used as an alternative to the capacitor 3. The control means operates so that the high-frequency voltage V9 included in the stray capacitance voltage VF becomes zero.
[0081]
Although the control current Icomb is supplied to the connection point in the series circuit here, it may be supplied directly to each power supply line as shown in FIG.
Thus, by omitting the capacitor 3 associated with the voltage detection circuit 8, further cost reduction can be realized.
[0082]
Embodiment 4 FIG.
In Embodiments 1 to 3 described above, the pseudo power supply circuit network 16 is inserted on the input side of the power conversion device 4, but an impedance element (reactor) may be inserted.
[0083]
FIG. 6 is a circuit configuration diagram schematically showing Embodiment 4 of the present invention. Components similar to those described above (see FIG. 1) are denoted by the same reference numerals, or suffixed with “c”. Detailed description will be omitted.
[0084]
In FIG. 6, the difference from the first embodiment described above is that reactors 40 to 42 are inserted on the input side of power conversion device 4 instead of pseudo power supply network 16.
That is, reactors 40 to 42 are inserted between a connection point between each power supply line and capacitor 3 and AC power supply 1.
[0085]
As described above, in actual operation of the power conversion device 4, the pseudo power supply circuit network 16 that functions as a conduction noise measuring device is removed, and the AC power supply 1 is directly connected to the power conversion device 4.
[0086]
At this time, when the system power impedance is present in the AC power source 1, the voltage difference between the voltage V3 of the capacitor 3 (or the stray capacitance CF corresponding to the capacitor 3) and the AC power source 1 is applied to the system impedance. The high frequency voltage of the capacitor 3 (or stray capacitance CF) can be controlled.
[0087]
However, when the system impedance present in the AC power supply 1 is zero (or not sufficiently large), the voltage of the AC power supply 1 is always applied almost as it is to the capacitor 3 (or the stray capacitance CF). Therefore, the high frequency voltage of the capacitor 3 (or stray capacitance CF) cannot be controlled.
[0088]
In order to avoid this, as shown in FIG. 6, reactors 40 to 42 are inserted between AC power supply 1 and power converter 4, and voltage V3 of capacitor 3 (or stray capacitance CF) and AC power supply 1 are Is applied to reactors 40-42.
[0089]
Thereby, even when the system impedance existing in the AC power supply 1 is small, the high frequency component of the voltage V3 of the capacitor 3 (or the stray capacitance CF) can be suppressed, and the conductive noise appearing in the AC power supply 1 can be suppressed. Can do.
[0090]
In addition, since only the high-frequency differential voltage needs to be applied to the reactors 40 to 42, the reactors 40 to 42 have a small capacity and a low cost compared with the conventional noise reduction (filter) reactors (see FIGS. 9 to 12). Can be realized.
[0091]
Embodiment 5 FIG.
In the first to fourth embodiments, the case where the power supply line is a power supply line from the AC power supply 1 has been described. However, even if the power supplied via the power supply line is a DC power supply, Has an effect.
[0092]
FIG. 7 is a circuit configuration diagram schematically showing Embodiment 5 of the present invention. Components similar to those described above (see FIG. 1) are denoted by the same reference numerals, or suffixed with “d”. Detailed description will be omitted.
[0093]
In FIG. 7, DC power from the DC power source 1d is supplied to the power conversion device 4d via positive and negative power supply lines.
The power conversion device 4 d includes a capacitor 14 connected to a power supply line and a DC / AC conversion unit 15 that supplies AC power to the load 5.
[0094]
Also in this case, in order to avoid complexity, the capacitor 3, the series circuit (the capacitor 6 and the resistor 7), and the control means are shown for only one phase.
[0095]
As shown in FIG. 7, even when the DC power supply 1d is used as the power supply to the power conversion device 4d, it is possible to prevent the voltage due to the high frequency noise generated by the power conversion device 4d from appearing on the system side of the DC power supply 1d. it can.
[0096]
Furthermore, although the case where the DC power source 1d is applied to the circuit configuration of the first embodiment (see FIG. 1) is shown here, it is applied to the circuit configurations of the second to fourth embodiments (see FIGS. 4 to 6). However, it goes without saying that the same effects can be achieved.
[0097]
【The invention's effect】
As described above, according to the present invention, there is provided a noise reduction device for a power conversion device that is connected to a power source via a plurality of power supply lines and supplies converted power to a load. Capacitance element inserted between the lines, voltage detection circuit for detecting the voltage of the capacitance element, and control means for supplying a control current corresponding to the voltage of the capacitance element to each power supply line side And the control means is configured to suppress the high-frequency voltage component existing in the capacitance element by the control current so that the supply current of the power converter does not flow to the noise reduction filter. There is an effect that it is possible to obtain a noise reduction device for a power conversion device that can reduce the size and simultaneously reduce both normal mode noise and common mode noise.
[0098]
In addition, according to the present invention, the impedance circuit inserted between each power supply line and the ground line is provided, the electrostatic capacitance element includes the first capacitor, and the impedance circuit includes the second capacitor and the resistor. Since the control means is configured to supply the control current to the connection point between the second capacitor and the resistor in accordance with the voltage of the first capacitor, the control means has a relatively simple circuit configuration. Thus, it is possible to obtain a noise reduction device for a power conversion device that can reduce the size of the filter and simultaneously reduce both normal mode noise and common mode noise.
[0099]
In addition, according to the present invention, a series circuit composed of a capacitor and a resistor inserted between each power supply line and the ground line is provided, and the capacitance element is provided between each power supply line and the ground line. Consisting of stray capacitance, the control means supplies the control current to the connection point between the capacitor and the resistor according to the stray capacitance voltage, which further reduces costs and reduces the size of the filter. There is an effect that a noise reduction device for a power conversion device capable of simultaneously reducing both mode noise and common mode noise can be obtained.
[0100]
In addition, according to the present invention, the electrostatic capacitance element is composed of a capacitor, and the control means supplies the control current directly to each power supply line in accordance with the voltage of the capacitor. There is an effect of obtaining a noise reduction device for a power conversion device that can reduce the size of the filter with the configuration and can simultaneously reduce both normal mode noise and common mode noise.
[0101]
Further, according to the present invention, the electrostatic capacitance element comprises a stray capacitance between each power supply line and the ground line, and the control means applies a control current to each power supply line according to the voltage of the stray capacitance. Since it is directly supplied, it is possible to further reduce the cost and reduce the size of the filter, and to obtain a noise reduction device for a power conversion device that can simultaneously reduce both normal mode noise and common mode noise. .
[0102]
According to the present invention, the control means includes a high-pass filter, a subtractor, an arithmetic controller, and a current generator. The high-pass filter passes a high-frequency component included in the output signal of the voltage detection circuit, and the subtractor The output signal of the high pass filter is subtracted from the zero signal, the arithmetic controller calculates a current command value based on the output signal of the subtractor, and the current generator uses the current value corresponding to the current command value as the control current. Since the output is achieved, the filter can be reduced in size with a relatively simple circuit configuration, and a noise reduction device for a power converter that can simultaneously reduce both normal mode noise and common mode noise can be obtained. There is.
[0103]
Further, according to the present invention, the impedance element is inserted between the connection point between each power supply line and the capacitance element and the power source, and the impedance element includes the voltage of the power source and the voltage of the capacitance element. Therefore, even when the system impedance existing in the power supply is small, it is possible to obtain a noise reduction device for a power conversion device that can simultaneously reduce both normal mode noise and common mode noise. effective.
[0104]
Further, according to the present invention, since the impedance element is made of a reactor, even when the system impedance existing in the power supply is small, the noise reduction of the power converter that can simultaneously reduce both normal mode noise and common mode noise. There is an effect that a device can be obtained.
[0105]
Further, according to the present invention, since the power source is an AC power source, even when an AC power source is used, it is possible to reduce the size of the filter and simultaneously reduce both normal mode noise and common mode noise. There is an effect that a noise reduction device for a power conversion device can be obtained.
[0106]
Further, according to the present invention, since the power source is a DC power source, even when a DC power source is used, it is possible to reduce the size of the filter and simultaneously reduce both normal mode noise and common mode noise. There is an effect that a noise reduction device for a power conversion device can be obtained.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram schematically showing a first embodiment of the present invention;
FIG. 2 is a circuit configuration diagram showing in detail a control means according to Embodiment 1 of the present invention;
FIG. 3 is a waveform diagram showing an operation according to the first embodiment of the present invention.
FIG. 4 is a circuit configuration diagram schematically showing a second embodiment of the present invention.
FIG. 5 is a circuit configuration diagram schematically showing a third embodiment of the present invention.
FIG. 6 is a circuit configuration diagram schematically showing a fourth embodiment of the present invention.
FIG. 7 is a circuit configuration diagram schematically showing a fifth embodiment of the present invention.
FIG. 8 is a circuit configuration diagram showing a conductive noise measuring apparatus using a conventional power converter.
FIG. 9 is a circuit configuration diagram schematically showing a general pseudo power supply circuit network;
FIG. 10 is an explanatory diagram showing a noise path flowing in a normal mode with respect to a general pseudo power supply circuit network;
FIG. 11 is an explanatory diagram showing a noise path flowing in a common mode with respect to a general pseudo power supply circuit network;
FIG. 12 is a circuit configuration diagram showing a noise reduction device of a conventional power conversion device using an LC filter.
FIG. 13 is a circuit configuration diagram showing an example of a conventional common mode noise suppression device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 AC power supply, 1d DC power supply, 2 Grounding point, 3, 6 Capacitor, 4, 4d Power converter, 5 Load, 7 Resistor, 8 Voltage detection circuit, 9 High pass filter, 10 Subtractor, 11, 11a-11d Controller, 12, 12a-12d Current generator, 40, 41, 42 Reactor, Icom *, Icoma * -Icomd * Current command value, Icom, Icoma-Icomd Control current,
V3 Capacitor voltage, VF Floating capacitance voltage.

Claims (10)

A noise reduction device for a power converter connected to a power source via a plurality of power supply lines to supply converted power to a load,
A capacitive element inserted between each power supply line and the ground line;
A voltage detection circuit for detecting a voltage of the capacitance element;
Control means for supplying a control current corresponding to the voltage of the capacitance element to each power supply line side,
The said control means suppresses the high frequency voltage component which exists in the said electrostatic capacitance element with the said control current, The noise reduction apparatus of the power converter device characterized by the above-mentioned. An impedance circuit inserted between each power supply line and the ground line;
The capacitance element comprises a first capacitor,
The impedance circuit comprises a series circuit composed of a second capacitor and a resistor,
2. The power conversion device according to claim 1, wherein the control unit supplies the control current to a connection point between the second capacitor and the resistor in accordance with a voltage of the first capacitor. Noise reduction device. A series circuit comprising a capacitor and a resistor inserted between each of the power supply lines and the ground line;
The capacitance element comprises a stray capacitance between each power supply line and the ground line,
2. The noise reduction device for a power conversion device according to claim 1, wherein the control unit supplies the control current to a connection point between the capacitor and the resistor in accordance with a voltage of the stray capacitance. The capacitance element comprises a capacitor,
2. The noise reduction device for a power converter according to claim 1, wherein the control unit directly supplies the control current to each of the power supply lines in accordance with a voltage of the capacitor. The capacitance element comprises a stray capacitance between each power supply line and the ground line,
2. The noise reduction device for a power converter according to claim 1, wherein the control unit directly supplies the control current to each of the power supply lines in accordance with a voltage of the stray capacitance. The control means includes a high pass filter, a subtractor, an arithmetic controller and a current generator,
The high-pass filter passes a high-frequency component included in the output signal of the voltage detection circuit,
The subtracter subtracts the output signal of the high pass filter from a zero signal,
The arithmetic controller calculates a current command value based on the output signal of the subtractor,
The said current generator outputs the electric current value according to the said electric current command value as said control current, The noise reduction apparatus of the power converter device in any one of Claim 1-5 characterized by the above-mentioned. An impedance element inserted between a connection point between each power supply line and the capacitance element and the power source;
The noise of the power converter according to any one of claims 1 to 6, wherein a differential voltage between the voltage of the power source and the voltage of the capacitance element is applied to the impedance element. Reduction device. The noise reduction device for a power conversion device according to claim 7, wherein the impedance element includes a reactor. The noise reduction device for a power converter according to any one of claims 1 to 8, wherein the power source is an AC power source. 9. The noise reduction device for a power conversion device according to claim 1, wherein the power source is a DC power source.

Images