Power Conversion Device

Abstract

To suppress a deterioration in compensation performance to common mode noise that is caused by superposition of switching noise of a power converter on a detection signal of the common mode noise.SOLUTION: A power conversion device comprises: a power converter using a switching element; and a noise reduction circuit that has noise detection means detecting a common mode noise current or a common mode noise voltage generated in a power line according to the operation of the power converter, an amplifier generating a compensation current on the basis of a detection signal generated by the noise detection means, and an output circuit outputting to the power line the compensation current generated by the amplifier. A power conversion substrate having the power converter mounted thereon and a canceler substrate having the amplifier mounted thereon are different from each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a power conversion device and a refrigeration device. [Background technology]

[0002] Patent Document 1 describes a noise reduction device for a power conversion device in which an electric motor is connected as a load to an inverter device consisting of an AC power supply, a rectifier circuit, a smoothing capacitor, and an inverter circuit, a leakage current detector is connected between the AC power supply and the rectifier circuit, a first NPN transistor is connected between one end of the smoothing capacitor and the case of the motor, and a second PNP transistor is connected between the case of the motor and the other end of the smoothing capacitor, and the first and second transistors are driven by the output of the leakage current detector to inject a current to cancel out common-mode noise. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3044650 Summary of the Invention [Problem to be solved by the invention]

[0004] A common mounting method is to mount a power converter using switching elements and an amplifier that generates a compensation current based on a detection signal of common-mode noise generated on a power line in response to the operation of the power converter on the same board. However, with this mounting method, there is a risk that the switching noise of the power converter will be superimposed on the detection signal of the common-mode noise, deteriorating the compensation performance for the common-mode noise.

[0005] An object of the present disclosure is to suppress deterioration of compensation performance for common mode noise caused by switching noise of a power converter being superimposed on a detection signal for common mode noise. [Means for solving the problem]

[0006] The power conversion device of the present disclosure is a power conversion device comprising: a power converter using a switching element; noise detection means for detecting common mode noise current or common mode noise voltage generated on a power line in accordance with the operation of the power converter; an amplifier for generating a compensation current based on a detection signal from the noise detection means; and a noise reduction circuit having an output circuit for outputting the compensation current generated by the amplifier to the power line, wherein a power conversion board on which the power converter is mounted and a canceller board on which the amplifier is mounted are different boards.

[0007] This power conversion device can suppress deterioration of compensation performance for common mode noise caused by switching noise of the power converter being superimposed on the detection signal for common mode noise.

[0008] The power conversion device of the present disclosure includes: a power converter using a switching element; noise detection means for detecting a common mode noise current or a common mode noise voltage generated on a power line in response to operation of the power converter; an amplifier for generating a compensation current based on a detection signal from the noise detection means; an output circuit for outputting the compensation current generated by the amplifier to the power line or to earth; a noise reduction circuit having a coupling capacitor connected to the power line; and a power supply terminal block to which an AC power supply is connected, wherein a power conversion board on which the power converter is mounted and a canceller board on which the amplifier is mounted are different boards, the power supply terminal block is provided separately from the canceller board on the AC power supply side of the canceller board, and the noise detection means is located between a connection point of the coupling capacitor on the power line and the power supply terminal block, and is located closer to the power supply terminal block than the connection point. .

[0009] This will increase the effect of compensating for common mode noise.

[0010] The power conversion device of the present disclosure may include a power supply terminal block to which an AC power supply is connected, and the canceller board may be arranged closer to the power supply terminal block than the power conversion board.

[0011] In this way, it is possible to compensate for common mode noise while suppressing the influence of heat from the power converter.

[0012] The power conversion device of the present disclosure may include a noise filter between the noise reduction circuit and the power converter.

[0013] In this way, the switching noise from the power converter can be reduced.

[0014] The power conversion device of the present disclosure includes: a power converter using a switching element; a noise reduction circuit having a noise detection means for detecting a common mode noise current or a common mode noise voltage generated on a power line in response to operation of the power converter; an amplifier for generating a compensation current based on a detection signal from the noise detection means; and an output capacitor section for outputting the compensation current generated by the amplifier to ground; a power conversion board on which the power converter is mounted and a canceller board on which the amplifier is mounted are different boards; the output capacitor section is mounted on the canceller board; the canceller board has a compensation path connection terminal which is a terminal for outputting the compensation current from the noise reduction circuit via the output capacitor section; a noise filter is provided between the noise reduction circuit and the power converter; the noise filter has a plurality of Y capacitors each having one end connected to each phase of the power line and a ground terminal of the noise filter for grounding the other ends of the plurality of Y capacitors; and a housing that houses the power conversion board, the canceller board, and the noise filter and has a conductive part at the same potential as ground, and the compensation path connection terminal and the ground terminal of the noise filter are separately connected to the conductive part of the housing. .

[0015] In this way, it is possible to suppress the mixing of noise from the current recovered by the noise filter into the compensation current.

[0016] The terminal on the housing side to which the compensation path connection terminal is connected may be closer to the earth terminal of the housing than the terminal on the housing side to which the earth terminal of the noise filter is connected.

[0017] In this way, the impedance of the compensation path can be reduced.

[0018] Another power converter may be connected to the load side of the noise filter in parallel with the power converter.

[0019] In this way, switching noise from other power converters can also be canceled.

[0020] The power conversion device of the present disclosure includes a power converter using a switching element, noise detection means for detecting a common mode noise current or a common mode noise voltage generated on a power line in response to an operation of the power converter, an amplifier for generating a compensation current based on a detection signal from the noise detection means, an output circuit for outputting the compensation current generated by the amplifier to the power line or a ground, a DC power supply unit for supplying a DC voltage to the amplifier, a first capacitor having one end connected to the negative side of the DC power supply unit, a second capacitor having one end connected to the positive side of the DC power supply unit, and a connection point connecting the other end of the first capacitor and the other end of the second capacitor. and a common mode noise filter disposed between the noise reduction circuit and the power converter, wherein the noise reduction circuit has a coupling capacitor group, one end of which is connected to each phase of the power line between the noise detection means and the noise filter and the other ends of which are connected to each other and to the connection point, a power conversion board on which the power converter is mounted and a canceller board on which the amplifier, the coupling capacitor group, the first capacitor, and the second capacitor are mounted are different boards, and the noise filter is mounted on the canceller board. .

[0021] In this way, the impedance of the compensation path can be reduced.

[0022] Power for the noise reduction circuit may be supplied to the canceller board from another board, and a noise reduction element may be provided on the power supply path.

[0023] In this way, it is possible to suppress the switching noise of the power converter from leaking to the outside via the noise canceller.

[0024] Power for the noise reduction circuit may be supplied to the canceller board from another board.

[0025] In this way, the cost of operating the noise reduction circuit can be reduced.

[0026] The noise detection means may be a detection core that detects the common mode noise current.

[0027] In this way, the detected common mode noise current can be amplified as it is to compensate for the common mode noise.

[0028] A refrigeration device according to the present disclosure is a refrigeration device including any one of the power conversion devices described above.

[0029] According to this refrigeration apparatus, it is possible to suppress deterioration of compensation performance for common mode noise caused by the switching noise of the power converter being superimposed on the detection signal for common mode noise. [Brief explanation of the drawings]

[0030] [Figure 1-1] 1 is a diagram showing a circuit configuration of a power conversion system according to a first embodiment. [Figure 1-2] FIG. 4 is a diagram showing a modified example of the circuit configuration of the power conversion system in the first embodiment. [Figure 2] 1 is a diagram schematically illustrating a configuration of a power conversion system according to a first embodiment. [Figure 3] FIG. 4 is a diagram showing a circuit configuration of a power conversion system according to a second embodiment. [Figure 4] FIG. 10 is a diagram schematically illustrating a configuration of a power conversion system according to a second embodiment. [Figure 5] FIG. 10 is a diagram schematically illustrating a configuration of a power conversion system according to a third embodiment. [Figure 6] FIG. 10 is a diagram schematically illustrating a configuration of a power conversion system according to a fourth embodiment. [Figure 7] FIG. 10 is a diagram schematically illustrating a configuration of a power conversion system according to a fifth embodiment. [Figure 8] FIG. 10 is a diagram schematically illustrating a configuration of a power conversion system according to a sixth embodiment. [Figure 9] FIG. 12 is a diagram schematically illustrating a configuration of a power conversion system according to a seventh embodiment. [Figure 10] 1 is a diagram showing an example of a piping system of a refrigeration device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

[0032] [First embodiment] 1-1 is a diagram showing a circuit configuration of a power conversion system 1 according to a first embodiment. As shown in the figure, the power conversion system 1 includes an AC power supply 100, a motor 200, and a power conversion device 300.

[0033] The AC power supply 100 is, for example, a three-phase, three-wire commercial AC power supply, and supplies AC to the power conversion device 300. Here, the first to third phases are referred to as the R phase, S phase, and T phase. The power lines supplying the R phase, S phase, and T phase are referred to as the R phase, S phase, and T phase power lines. When no distinction is made between phases, they are referred to as power lines. Note that, although the following description will be given of a case where a three-phase, three-wire AC power supply is used, a similar concept can also be applied to a case where a three-phase, four-wire AC power supply or a single-phase AC power supply is used.

[0034] Motor 200 is connected to power conversion device 300 and is a motor controlled as a load by three-phase AC. Motor 200 may be, for example, a DC brushless motor. Alternatively, motor 200 may be another three-phase AC motor.

[0035] The power conversion device 300 includes a power terminal block 10 , a power converter 20 , and a noise reduction circuit 30 .

[0036] The power supply terminal block 10 is a part for connecting wiring for inputting AC from the AC power supply 100. The power supply terminal block 10 is provided with an R-phase input terminal, an S-phase input terminal, and a T-phase input terminal (not shown). The power supply terminal block 10 may also be provided with a ground terminal E0 to which an external ground wire is connected, although this is shown in the drawing at a position away from the power supply terminal block 10.

[0037] The power converter 20 includes a rectifier unit 21 and an inverter unit 23. In the power converter 20, the rectifier unit 21 and the inverter unit 23 are connected in this order from the AC power supply 100 side. The inverter unit 23 is connected to the motor 200.

[0038] The rectifier 21 rectifies the AC supplied from the AC power supply 100 into DC. The inverter 23 converts the DC output from the rectifier 21 into three-phase AC and supplies it to the motor 200. The inverter 23 includes a switching element (not shown). As the switching element, for example, an insulated gate bipolar transistor (IGBT) or the like may be used. Note that a smoothing unit may be provided between the rectifier 21 and the inverter 23 to smooth the DC output from the rectifier 21.

[0039] The noise reduction circuit 30 is an active common-mode noise reduction circuit that detects common-mode noise and suppresses it through feedback. The noise reduction circuit 30 includes a noise detection unit 31, a coupling capacitor unit 32, a DC power supply unit 33, a detection circuit 34, an amplifier 35, and an output capacitor unit 36.

[0040] The noise detection unit 31 detects a common-mode noise current. An example of the noise detection unit 31 is a detection core. The detection core may include a conductor that passes through a toroidal core, but here, an example including coils (windings) L1r, L1s, L1t, and L1a will be described.

[0041] Coils L1r, L1s, and L1t are connected in series to the power lines of the R, S, and T phases, respectively. Here, a coil refers to a conductor wound in a spiral (loop) shape to form an inductor.

[0042] These coils L1r, L1s, and L1t are conducting wires that form part of the power line and are wound around a single toroidal core. The toroidal core is made of a magnetic material such as ferrite and has a circular cross section (doughnut shape). A toroidal core is sometimes called an iron core. Note that the toroidal core does not have to be circular, and may be a polygonal frame shape such as a square or triangle. The cross section may also be a square, triangle, or other shape.

[0043] The coils L1r, L1s, and L1t are wound adjacent to each other around a single toroidal core. Therefore, the coils L1r, L1s, and L1t are magnetically coupled to each other. The coils L1r, L1s, and L1t are wound so that the polarity is as shown by "·" in Figure 1-1.

[0044] Coil L1a is arranged to be magnetically coupled to coils L1r, L1s, and L1t. For example, coil L1a is wound around a single toroidal core so as to be adjacent to coils L1r, L1s, and L1t. Alternatively, coils L1r, L1s, and L1t may be wound around a single toroidal core so as to be adjacent to each other, and coil L1a may be wound so as to overlap coils L1r, L1s, and L1t. Coil L1a is wound so as to have the polarity indicated by "·" in FIG. 1-1.

[0045] Coils L1r, L1s, L1t, and L1a are wound so that when current flows to the right in the diagram through coils L1r, L1s, and L1t, current flows to the left in coil L1a. Therefore, the polarity indicated by "·" above is the polarity according to the direction in which current flows.

[0046] The common mode noise current is a high frequency current that leaks to the ground via the stray capacitance of the motor 200, etc. due to the switching of the switching element St of the inverter unit 23. Therefore, the common mode noise current flows between the R-phase, S-phase, and T-phase power lines and the ground.

[0047] When common-mode noise current flows through coils L1r, L1s, and L1t, a current proportional to the common-mode noise current is induced in coil L1a via the toroidal core. In this case, coils L1r, L1s, L1t, and coil L1a function as a current transformer and form a detection transformer that detects the common-mode noise current.

[0048] The coupling capacitor section 32 includes a coupling capacitor Cc and capacitors C1 and C2. The capacitors C1 and C2 are connected in series and in parallel with the DC power supply section 33 and the amplifier 35. One of the three terminals of the coupling capacitor Cc is connected to the R-phase, S-phase, and T-phase power lines, respectively. The other terminal of the coupling capacitor Cc is connected to the connection point of the series-connected capacitors C1 and C2. The coupling capacitor section 32 then serves as a path for flowing a compensation current between the R-phase, S-phase, and T-phase power lines and the amplifier 35 via the coupling capacitor Cc and the capacitors C1 and C2.

[0049] 1-2, the coupling capacitor section 32 may include coupling capacitors Cc1 and Cc2. In this case, one of the three terminals of the coupling capacitor Cc1 is connected to the R-phase, S-phase, and T-phase power lines, respectively, and the other of the terminals of the coupling capacitor Cc1 is connected to the DC power supply section 33 and the amplifier 35. One of the three terminals of the coupling capacitor Cc2 is connected to the R-phase, S-phase, and T-phase power lines, respectively, and the other of the terminals of the coupling capacitor Cc2 is connected to the DC power supply section 33 and the amplifier 35.

[0050] The DC power supply unit 33 includes a DC power supply V. The DC power supply V supplies a DC voltage to the amplifier 35.

[0051] The detection circuit 34 includes a base resistor Rb. The base resistor Rb is a resistor for limiting the base current flowing through the amplifier 35. Here, the circuit connected between the connection part of the detection core and the base resistor Rb is defined as the detection circuit.

[0052] The amplifier 35 includes first and second transistors Tr1 and Tr2 as examples of first and second current control elements, and first and second diodes D1 and D2.

[0053] The first transistor Tr1 is connected between one end of the DC power supply V and the output capacitor section 36. The second transistor Tr2 is connected between the other end of the DC power supply V and the output capacitor section 36. The first transistor Tr1 is a PNP type, and the second transistor Tr2 is an NPN type, with the first and second transistors Tr1 and Tr2 having opposite polarities. The bases (control terminals) of the first and second transistors Tr1 and Tr2 are connected to one output line of the coil L1a, and the interconnection point of the first and second transistors Tr1 and Tr2 is connected to the other output line of the coil L1a. This causes the first and second transistors Tr1 and Tr2 to operate in opposite directions.

[0054] The first and second diodes D1 and D2 are connected in anti-parallel to the first and second transistors Tr1 and Tr2 to protect them, but the first and second diodes D1 and D2 do not necessarily have to be provided.

[0055] Although the amplifier 35 used here includes a transistor, it is not limited to a transistor and may include an operational amplifier.

[0056] The output capacitor section 36 includes an output capacitor Co. One end of the output capacitor Co is connected to a connection point on the emitter side of the first and second transistors Tr1 and Tr2, and the other end is connected to the ground terminal E1 of the housing via the compensation path connection terminal Ec. Note that a configuration may be adopted in which the output capacitor section 36 is not provided, or in which the output capacitor section 36 includes a resistor connected directly to the output capacitor Co. Alternatively, a configuration may be adopted in which the output capacitor section 36 is connected to the power line, and the DC power supply section 33 is connected to the ground directly or via a coupling capacitor.

[0057] In the first embodiment, the detection circuit 34, the amplifier 35, and the output capacitor section 36 constitute a noise canceller.

[0058] Here, the operation of the power conversion system 1 in the first embodiment will be described.

[0059] A commercial AC power supply 100 supplies AC voltage to a power converter 20 via a power terminal block 10. In the power converter 20, a rectifier 21 rectifies the AC voltage supplied from the AC power supply 100 into a DC voltage. An inverter 23 supplies AC voltage to a motor 200 by controlling the on / off of a switching element.

[0060] At this time, as shown in the figure, a common-mode noise current Ic flows from the motor 200 each time a pulsed voltage is applied from the inverter unit 23. The noise detection unit 31 detects the common-mode noise current in the power line input to the power converter 20 and drives the first and second transistors Tr1 and Tr2. When the current detected by the noise detection unit 31 flows into the bases of the first and second transistors Tr1 and Tr2, it is amplified by the first and second transistors Tr1 and Tr2.

[0061] When the first transistor Tr1 is on (when a positive common-mode noise current Ic is generated), the compensation current Io is supplied from the DC power supply V and flows through a current path (compensation path) that connects the positive terminal of the DC power supply V to the negative terminal of the DC power supply V via capacitor C2, coupling capacitor Cc, AC power supply 100, output capacitor Co, and first transistor Tr1. In this case, the common-mode noise current Ic, compensation current Io, and compensated common-mode noise current Ig flow in the directions shown by the arrows in the figure. The compensation current Io is subtracted from the common-mode noise current Ic from the motor 200, thereby reducing the common-mode noise current Ic. In other words, the compensation current Io compensates for the common-mode noise current Ic.

[0062] When the second transistor Tr2 is on (when a negative common-mode noise current Ic is generated), the compensation current Io is supplied from the DC power supply V and flows through a current path (compensation path) that connects the positive terminal of the DC power supply V to the negative terminal of the DC power supply V via the second transistor Tr2, output capacitor Co, AC power supply 100, coupling capacitor Cc, and capacitor C1. In this case, the common-mode noise current Ic, compensation current Io, and compensated common-mode noise current Ig flow in the direction opposite to the arrows in the figure. The negative compensation current Io is subtracted from the negative common-mode noise current Ic from the motor 200, thereby reducing the common-mode noise current Ic. In other words, the compensation current Io compensates for the common-mode noise current Ic.

[0063] As described above, the compensated common-mode noise current Ig flows through the AC power supply 100 whether the first transistor Tr1 is on or the second transistor Tr2 is on.

[0064] In the first embodiment, the noise detection unit 31 detects a common-mode noise current, but the noise detection unit 31 may also detect a common-mode noise voltage. In this case, the noise reduction circuit 30 may estimate the common-mode noise current flowing in the path from the common-mode noise voltage detected by the noise detection unit 31, and may flow a compensation current so as to cancel out the common-mode noise current.

[0065] FIG. 2 is a diagram schematically illustrating the configuration of a power conversion system 1 according to the first embodiment.

[0066] In the first embodiment, as shown in the figure, the power conversion board 510 on which the power converter 20 is mounted and the canceller board 520 on which the detection circuit 34, the amplifier 35, and the output capacitor section 36 are mounted are configured as different boards.

[0067] As described above, in the first embodiment, the inverter unit 23, which is a source of switching noise, and the noise canceller are mounted on separate boards, thereby increasing the distance between the inverter unit 23 and the noise canceller. This reduces the superimposition of switching noise from the inverter unit 23 on the detection signal of common mode noise, allowing the noise canceller to operate stably. Furthermore, the superimposition of switching noise from the inverter unit 23 on the compensation current can also be reduced, improving compensation performance.

[0068] In an active noise canceller, the detection signal is amplified and compensated for, so it is highly sensitive to disturbance noise and has a greater effect in separating the board than a normal passive noise filter.

[0069] Furthermore, in the first embodiment, the degree of freedom in mounting position is increased, making it possible to configure a low-impedance compensation path. Moreover, regardless of the specifications (input power supply voltage, load capacity, etc.) of the power conversion board 510, the noise reduction circuit 30 can be standardized, thereby reducing costs.

[0070] In the figure, the noise detection unit 31, the coupling capacitor unit 32, and the DC power supply unit 33 are not mounted on the canceller substrate 520, but the noise detection unit 31, the coupling capacitor unit 32, and the DC power supply unit 33 may be mounted on the canceller substrate 520. Also, in the figure, the detection circuit 34 and the output capacitor unit 36 ​​are mounted on the canceller substrate 520, but the detection circuit 34 and the output capacitor unit 36 ​​do not have to be mounted on the canceller substrate 520. It is sufficient that at least the amplifier 35 is mounted on the canceller substrate 520.

[0071] In the first embodiment, the noise detection unit 31 is disposed closer to the power terminal block 10 than the power conversion board 510, as shown in the drawing.

[0072] In this way, in the first embodiment, by arranging the noise detection unit 31 near the power terminal block 10, it becomes possible to compensate for common mode noise at the power terminal block 10. This increases the effect of compensating for common mode noise.

[0073] Furthermore, in the first embodiment, as shown in the figure, the canceller board 520 is arranged closer to the power terminal block 10 than the power conversion board 510. Specifically, the power conversion board 510 and the canceller board 520 are arranged so that the distance DS2 in the figure is shorter than the distance DS1 in the figure.

[0074] In this way, in the first embodiment, by separating the canceller substrate 520 from the power converter 20, it is possible to reduce the influence of heat from the power conversion substrate 510 on the canceller substrate 520. This allows the noise canceller to operate stably.

[0075] Furthermore, if the power supply voltage of the noise canceller is reduced, sufficient compensation current cannot flow unless the impedance of the compensation path is reduced. By placing the noise canceller near the power terminal block, the impedance of the compensation path can be reduced, which has a greater effect on low-voltage noise cancellers.

[0076] [Second embodiment] 3 is a diagram showing a circuit configuration of a power conversion system 2 in the second embodiment. As shown in the figure, the power conversion system 2 includes an AC power supply 100, a motor 200, and a power conversion device 400.

[0077] The AC power supply 100 and the motor 200 are the same as those described in the first embodiment, and therefore a description thereof will be omitted.

[0078] The power conversion device 400 includes a power terminal block 10, a power converter 20, a noise reduction circuit 30, and a noise filter 40.

[0079] The power terminal block 10, the power converter 20, and the noise reduction circuit 30 are the same as those described in the first embodiment, and therefore a description thereof will be omitted.

[0080] The noise filter 40 is connected between the power converter 20 and the noise reduction circuit 30. The noise filter 40 reduces common mode noise. The noise filter 40 includes common mode choke coils L2r, L2s, and L2t and a Y capacitor Cy. The common mode choke coils L2r, L2s, and L2t are pairs of coils connected to the R-phase, S-phase, and T-phase power lines, respectively. The Y capacitor Cy is a capacitor provided between the R-phase, S-phase, and T-phase power lines and the ground. The Y capacitor Cy is connected to the ground terminal E2 of the housing via the ground terminal Ef of the noise filter 40.

[0081] Here, the operation of the power conversion system 2 in the second embodiment is the same as the operation of the power conversion system 1 in the first embodiment except that the noise filter 40 reduces switching noise from the power converter 20, so a description thereof will be omitted.

[0082] In the second embodiment, the noise detection unit 31 detects a common-mode noise current, but the noise detection unit 31 may also detect a common-mode noise voltage. In this case, the noise reduction circuit 30 may estimate the common-mode noise current flowing in the path from the common-mode noise voltage detected by the noise detection unit 31, and may flow a compensation current so as to cancel out the common-mode noise current.

[0083] FIG. 4 is a diagram schematically illustrating the configuration of a power conversion system 2 according to the second embodiment.

[0084] In the second embodiment, a noise filter 40 is connected between the noise reduction circuit 30 and the power conversion board 510 as shown in the drawing.

[0085] As a result, in the second embodiment, switching noise from the power converter 20 is reduced, and stable operation of the noise canceller can be expected.

[0086] 4, the noise filter 40 is connected between the noise reduction circuit 30 and the power conversion board 510, but may be connected between the noise reduction circuit 30 and the power converter 20. For example, the noise filter 40 may be mounted on the power conversion board 510.

[0087] [Third embodiment] The circuit configuration of the power conversion system 3 in the third embodiment is the same as the circuit configuration of the power conversion system 2 in the second embodiment.

[0088] FIG. 5 is a diagram schematically illustrating the configuration of a power conversion system 3 according to the third embodiment.

[0089] In the third embodiment, as shown in the figure, a housing 600 is provided to house the power conversion device 400. The housing 600 has a ground terminal E0 to which an external ground wire is connected. The compensation path connection terminal Ec of the canceller substrate 520 and the ground terminal Ef of the noise filter 40 are separately connected to the housing 600.

[0090] As described above, in the third embodiment, the current recovered by the passive noise filter 40 is separated from the compensation current, making it possible to prevent noise from being mixed into the compensation current.

[0091] In the above description, the entire housing 600 is a conductive part that has the same potential as the ground terminal E0, but this is not limited to this. The housing 600 may have a conductive part where only a part of it has the same potential as the ground terminal E0. In this case, it is preferable to arrange the ground terminal E1 on the housing 600 side to which the compensation path connection terminal Ec of the canceller substrate 520 is connected, and the ground terminal E2 on the housing 600 side to which the ground terminal Ef of the noise filter 40 is connected, on this conductive part.

[0092] In the third embodiment, as shown in the figure, the ground terminal E1 is disposed closer to the ground terminal E0 than the ground terminal E2. Specifically, the ground terminals E1 and E2 are disposed so that the distance DE1 in the figure is shorter than the distance DE2 in the figure.

[0093] As a result, in the third embodiment, it is possible to reduce the impedance of the compensation path.

[0094] [Fourth embodiment] The circuit configuration of the power conversion system 4 in the fourth embodiment is basically the same as the circuit configuration of the power conversion system 2 in the second embodiment.

[0095] FIG. 6 is a diagram schematically showing the configuration of a power conversion system 4 according to the fourth embodiment.

[0096] In the fourth embodiment, as shown in the drawing, in addition to the power conversion board 510, a plurality of power conversion boards 510a, 510b, ... are connected in parallel to the load side of the noise filter 40. Here, the plurality of power conversion boards 510a, 510b, ... may each be equipped with a power converter 20a, 20b, ....

[0097] Alternatively, any of the power converters 20a, 20b, ... may be an active filter. In this case, the active filter is connected in parallel between the noise filter 40 and the power converter 20 on the power line. The active filter reduces the harmonic current flowing from the power converter 20 to the power line by compensating for harmonic currents that are in antiphase with the harmonic currents generated in the power converter 20, based on the value of the current flowing through the power converter 20 detected by a current transformer (not shown) on the power line.

[0098] As a result, in the fourth embodiment, noises from a plurality of power conversion boards 510 can be cancelled collectively.

[0099] In the above description, the plurality of power conversion boards 510, 510a, 510b, etc. are respectively equipped with the power converters 20, 20a, 20b, etc. However, this is not limited to this. One power conversion board may be equipped with the power converters 20, 20a, 20b, etc. In other words, the other power converters 20a, 20b, etc. may be connected in parallel to the power converter 20 on the load side of the noise filter 40.

[0100] [Fifth embodiment] The circuit configuration of the power conversion system 5 in the fifth embodiment is the same as the circuit configuration of the power conversion system 2 in the second embodiment.

[0101] FIG. 7 is a diagram schematically illustrating the configuration of a power conversion system 5 according to the fifth embodiment.

[0102] In the fifth embodiment, as shown in the figure, instead of the canceller substrate 520 equipped with the detection circuit 34, the amplifier 35 and the output capacitor section 36, a canceller substrate 530 is provided which further equipped with the coupling capacitor section 32, the DC power supply section 33 and the noise filter 40.

[0103] As a result, in the fifth embodiment, the wiring connecting the power line and the coupling capacitor section 32, and the wiring connecting the coupling capacitor section 32 and the amplifier 35 can be shortened, thereby reducing the impedance of the compensation path.

[0104] In the figure, the DC power supply unit 33, the detection circuit 34, and the output capacitor unit 36 ​​are mounted on the canceller substrate 530, but the DC power supply unit 33, the detection circuit 34, and the output capacitor unit 36 ​​do not have to be mounted on the canceller substrate 530. It is sufficient to mount at least the coupling capacitor unit 32, the amplifier 35, and the noise filter 40 on the canceller substrate 530.

[0105] [Sixth embodiment] The circuit configuration of the power conversion system 6 in the sixth embodiment is the same as the circuit configuration of the power conversion system 1 in the first embodiment.

[0106] FIG. 8 is a diagram schematically showing the configuration of a power conversion system 6 according to the sixth embodiment.

[0107] In the sixth embodiment, as shown in the drawing, a power supply harness 540 is provided between the power conversion board 510 and the canceller board 520. The power supply harness 540 supplies power from the switching power supply of the power conversion board 510 to the canceller board 520.

[0108] As a result, in the sixth embodiment, it is possible to supply power to the canceller substrate 520 using the power supply circuit used in the power converter 20, leading to cost reduction.

[0109] Power may be supplied to the canceller board 520 from a board other than the power conversion board 510.

[0110] [Seventh embodiment] The circuit configuration of the power conversion system 7 in the seventh embodiment is the same as the circuit configuration of the power conversion system 2 in the second embodiment.

[0111] FIG. 9 is a diagram schematically showing the configuration of a power conversion system 7 according to the seventh embodiment.

[0112] In the configuration of the seventh embodiment, as shown in the drawing, a power supply harness 550 is provided between the power conversion board 510 and the canceller board 520. The power supply harness 550 supplies power from the switching power supply of the power conversion board 510 to the canceller board 520.

[0113] However, if the canceller board 520 is placed on the opposite side of the noise filter 40 from the power conversion board 510, the power supply harness 550 will connect the circuit on the AC power supply 100 side of the noise filter 40 to the circuit on the power converter 20 side. This will form a path with lower impedance than the noise filter 40, and noise from the power converter 20 will flow out to the AC power supply 100 side via the power supply harness 550. Therefore, in the seventh embodiment, a noise reduction element 551 is provided in the power supply harness 550. The noise reduction element 551 may be, for example, a ferrite core or the like.

[0114] As a result, in the seventh embodiment, it is possible to suppress the switching noise of the power converter 20 from leaking to the outside via the noise canceller.

[0115] Power may be supplied to the canceller board 520 from a board other than the power conversion board 510.

[0116] [Refrigeration equipment] 10 is a diagram showing an example of a piping system of a refrigeration device 9 in this embodiment. The refrigeration device 9 performs a refrigeration cycle by circulating a refrigerant in a refrigerant circuit 90. In the refrigerant circuit 90, as shown in the figure, a compressor 91, a condenser 92, an expansion mechanism 93, and an evaporator 94 are connected in this order by piping.

[0117] The compressor 91 compresses a low-pressure gas refrigerant and discharges a high-pressure gas refrigerant using the power of the motor 200. The motor 200 is included in the power conversion systems 1 to 7 in the first to seventh embodiments, and the power conversion devices 300 and 400 drive the motor 200 using the AC power supply 100 as a power source.

[0118] The condenser 92 condenses the high-pressure gas refrigerant discharged from the compressor 91 and discharges high-pressure liquid refrigerant. The expansion mechanism 93 expands the high-pressure liquid refrigerant discharged from the condenser 92 and discharges a low-pressure gas-liquid mixed refrigerant. The evaporator 94 evaporates the expanded low-pressure gas-liquid mixed refrigerant discharged from the expansion mechanism 93 and discharges a low-pressure gas refrigerant.

[0119] [Effects of the embodiment] The power conversion devices 300, 400 of this embodiment include a power converter 20 using a switching element, a noise detection unit 31 that detects a common mode noise current or a common mode noise voltage generated on a power line in response to the operation of the power converter 20, an amplifier 35 that generates a compensation current based on a detection signal from the noise detection unit 31, and a noise reduction circuit 30 that includes a coupling capacitor unit 32 that outputs the compensation current generated by the amplifier 35 to the power line. A power conversion board 510 on which the power converter 20 is mounted and a canceller board 520 on which the amplifier 35 is mounted are different boards.

[0120] According to the power conversion devices 300 and 400, it is possible to suppress deterioration of compensation performance for common mode noise caused by the switching noise of the power converter being superimposed on the detection signal for common mode noise.

[0121] The power conversion devices 300 and 400 of this embodiment are The power converter 20 includes a power converter using a switching element, a noise detection unit 31 that detects a common-mode noise current or a common-mode noise voltage generated on a power line in response to the operation of the power converter 20, an amplifier 35 that generates a compensation current based on a detection signal from the noise detection unit 31, an output capacitor Co that outputs the compensation current generated by the amplifier 35 to the power line or to earth, a noise reduction circuit 30 having a coupling capacitor Cc or coupling capacitors Cc1 and Cc2 connected to the power line, and a power supply terminal block 10 to which an AC power supply 100 is connected. A power conversion board 510 on which the power converter 20 is mounted and a canceller board 520 on which the amplifier 35 is mounted are different boards, and the power supply terminal block 10 is provided separately from the canceller board 520 on the AC power supply 100 side of the canceller board 520. The noise detection unit 31 is located between the connection point of the coupling capacitor Cc or coupling capacitors Cc1 and Cc2 on the power line and the power supply terminal block 10, and is located closer to the power supply terminal block 10 than the connection point. .

[0122] This will increase the effect of compensating for common mode noise.

[0123] The power conversion devices 300, 400 of the present embodiment may include a power supply terminal block 10 to which an AC power supply 100 is connected, and the canceller substrate 520 may be arranged closer to the power supply terminal block 10 than the power conversion substrate 510.

[0124] In this way, it is possible to suppress the influence of heat from the power converter 20 and compensate for common mode noise.

[0125] The power conversion device 400 of this embodiment may include a noise filter 40 between the noise reduction circuit 30 and the power converter 20.

[0126] In this way, the switching noise from the power converter 20 can be reduced.

[0127] The power conversion device 400 of this embodiment has: The noise reduction circuit 30 includes a power converter 20 using a switching element, a noise detection unit 31 that detects a common-mode noise current or a common-mode noise voltage generated on a power line in response to the operation of the power converter 20, an amplifier 35 that generates a compensation current based on a detection signal from the noise detection unit 31, and an output capacitor unit 36 ​​that outputs the compensation current generated by the amplifier 35 to earth. The power conversion board 510 on which the power converter 20 is mounted and the canceller board 520 on which the amplifier 35 is mounted are different boards, the canceller board 520 is mounted with the output capacitor section 36, and the canceller board 520 has a compensation path connection terminal which is a terminal for outputting a compensation current from the noise reduction circuit 30 via the output capacitor section 36, a noise filter 40 is provided between the noise reduction circuit 30 and the power converter 20, the noise filter 40 has a plurality of Y capacitors Cy each having one end connected to each phase of the power line, and an earth terminal of the noise filter 40 for grounding the other ends of the plurality of Y capacitors Cy, a housing 600 is provided which houses the power conversion board 510, the canceller board 520 and the noise filter 40 and has a conductive part which has the same potential as the earth, and the compensation path connection terminal and the earth terminal of the noise filter 40 are separately connected to the conductive part of the housing 600. .

[0128] In this way, it is possible to suppress the mixing of noise from the current collected by the noise filter 40 into the compensation current.

[0129] In this embodiment, the terminal on the housing 600 side to which the compensation path connection terminal is connected may be closer to the earth terminal of the housing 600 than the terminal on the housing 600 side to which the earth terminal of the noise filter 40 is connected.

[0130] In this way, the impedance of the compensation path can be reduced.

[0131] In this embodiment, other power converters 20a, 20b, . . . may be connected in parallel to the power converter 20 on the load side of the noise filter 40.

[0132] In this way, the switching noises from the other power converters 20a, 20b, . . . can also be cancelled.

[0133] a noise detection unit 31 that detects a common-mode noise current or a common-mode noise voltage generated on a power line in response to the operation of the power converter 20; an amplifier 35 that generates a compensation current based on a detection signal from the noise detection unit 31; an output capacitor Co that outputs the compensation current generated by the amplifier 35 to the power line or earth; a DC power supply unit 33 that supplies a DC voltage to the amplifier 35; a noise reduction circuit 30 having one end connected to the negative side of the DC power supply unit 33, a capacitor C1 having one end connected to the positive side of the DC power supply unit 33, and a connection point connecting the other end of the capacitor C1 and the other end of the capacitor C2; and a common-mode noise filter 40 that is arranged between the noise reduction circuit 30 and the power converter 20. The noise reduction circuit 30 includes a coupling capacitor group Cc, one end of which is connected to each phase of the power line between the noise detection unit 31 and the noise filter 40, and the other ends of which are connected to each other and to the connection point. The power conversion board 510 on which the power converter 20 is mounted and the canceller board 520 on which the amplifier 35, the coupling capacitor group Cc, the capacitor C1, and the capacitor C2 are mounted are different boards, and the noise filter 40 is mounted on the canceller board 520. .

[0134] In this way, the impedance of the compensation path can be reduced.

[0135] In this embodiment, power for the noise reduction circuit 30 may be supplied from the power conversion board 510 to the canceller board 520, and a noise reduction element 551 may be provided on the power supply path.

[0136] In this way, it is possible to prevent the switching noise of the power converter 20 from leaking to the outside via the noise canceller.

[0137] In this embodiment, the power supply for the noise reduction circuit 30 may be supplied from the power conversion board 510 to the canceller board 520 .

[0138] In this way, the cost of operating the noise reduction circuit 30 can be reduced.

[0139] In this embodiment, the noise detection unit 31 may be a detection core that detects a common-mode noise current.

[0140] In this way, the detected common mode noise current can be amplified as it is to compensate for the common mode noise.

[0141] The refrigeration device 9 of this embodiment includes any one of the power conversion devices 300, 400 described above.

[0142] According to this refrigeration device 9, it is possible to suppress deterioration of compensation performance for common mode noise caused by the switching noise of the power converter 20 being superimposed on the detection signal of the common mode noise.

[0143] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. [Explanation of symbols]

[0144] 1 to 7... power conversion system, 10... power supply terminal block, 20... power converter, 21... rectifier section, 23... inverter section, 30... noise reduction circuit, 31... noise detection section, 32... coupling capacitor section, 33... DC power supply section, 34... detection circuit, 35... amplifier, 36... output capacitor section, 40... noise filter, 100... AC power supply, 200... motor, 300, 400... power conversion device, 510... power conversion board, 520, 530... canceller board, 540, 550... power supply harness, 551 noise reduction element, 600... housing

Claims

1. a power converter using a switching element; a noise reduction circuit including: noise detection means for detecting a common mode noise current or a common mode noise voltage generated on a power line in response to an operation of the power converter; an amplifier for generating a compensation current based on a detection signal from the noise detection means; an output circuit for outputting the compensation current generated by the amplifier to the power line or to earth; and a coupling capacitor connected to the power line; A power terminal block to which AC power is connected Equipped with a power conversion board on which the power converter is mounted and a canceller board on which the amplifier is mounted are different boards, the power supply terminal block is provided on the AC power supply side of the canceller board, separately from the canceller board; The power conversion device, wherein the noise detection means is located between the connection point of the coupling capacitor on the power line and the power terminal block, and is arranged closer to the power terminal block than the connection point.

2. a power converter using a switching element; a noise reduction circuit including: noise detection means for detecting a common mode noise current or a common mode noise voltage generated on a power line in response to an operation of the power converter; an amplifier for generating a compensation current based on a detection signal from the noise detection means; and an output capacitor section for outputting the compensation current generated by the amplifier to a ground; A power terminal block to which AC power is connected Equipped with a power conversion board on which the power converter is mounted and a canceller board on which the amplifier is mounted are different boards, the output capacitor unit is mounted on the canceller substrate, the canceller substrate includes a compensation path connection terminal that is a terminal for outputting a compensation current from the noise reduction circuit via the output capacitor unit, a noise filter between the noise reduction circuit and the power converter; the noise filter includes a plurality of Y capacitors, one end of each of which is connected to each phase of the power line, and a ground terminal of the noise filter for grounding the other ends of the plurality of Y capacitors; a housing that houses the power conversion board, the canceller board, and the noise filter and has a conductive part that has the same potential as a ground; the compensation path connection terminal and the ground terminal of the noise filter are separately connected to the conductive part of the housing, The power supply terminal block is provided separately from the canceller board on the AC power supply side of the canceller board.

3. a power converter using a switching element; a noise reduction circuit including: noise detection means for detecting a common mode noise current or a common mode noise voltage generated on a power line in response to an operation of the power converter; an amplifier for generating a compensation current based on a detection signal from the noise detection means; an output circuit for outputting the compensation current generated by the amplifier to the power line or a ground; a DC power supply unit for supplying a DC voltage to the amplifier; a first capacitor having one end connected to the negative side of the DC power supply unit; a second capacitor having one end connected to the positive side of the DC power supply unit; and a connection point connecting the other end of the first capacitor and the other end of the second capacitor; a common mode noise filter disposed between the noise reduction circuit and the power converter; A power terminal block to which AC power is connected Equipped with the noise reduction circuit includes a group of coupling capacitors, one end of which is connected to each phase of the power line between the noise detection means and the noise filter, and the other ends of which are connected to each other and to the connection point; a power conversion board on which the power converter is mounted and a canceller board on which the amplifier, the coupling capacitor group, the first capacitor, and the second capacitor are mounted are different boards, the noise filter is mounted on the canceller substrate, The power supply terminal block is provided separately from the canceller board on the AC power supply side of the canceller board.

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