JP2018207556A - Electric power conversion system and refrigerating device - Google Patents

Abstract

To reduce influence that heat radiation from a reactive element connected to a converter and an inverter applies to a control part for controlling the inverter.SOLUTION: A discharge circuit includes a capacitor C4, and applies an electric power to a DC power supply line connected to an output power side of a converter 2. A charging circuit includes a reactor L4, and charges the capacitor C4 with an energy accumulated in the reactor L4 by receiving an electric power from the DC power supply line. An inverter 5 DC-AC converts a voltage between the DC power supply line, and outputs an AC current to a load. A cooling device 8 cools at least the inverter 5. A control part 109 outputs an inverter control signal for controlling the inverter 5. The control part 109 is arranged on an opposite side through the cooling device 8 to the capacitor C4 and the reactor L4.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power converter, and more particularly to a direct power converter having a power buffer circuit.

  As a direct power converter, power is transferred between a converter that performs AC / DC conversion, an inverter that performs DC / AC conversion, a DC power line pair that connects the converter and the inverter, and a DC power line pair. A configuration having a power buffer circuit is known. The power buffer circuit includes a charging circuit and a discharging circuit. Hereinafter, the direct power converter having such a configuration is tentatively referred to as “power converter with power buffer”.

  In a power converter with a power buffer, a configuration in which a low pass filter is provided between a converter and a DC power supply line pair is also known. Such a configuration is introduced in Patent Documents 1 and 2, for example. Compared with the case where a low-pass filter is provided before the converter (on the AC power supply side), the configuration in which the low-pass filter is provided between the converter and the DC power supply line pair reduces the rated voltage of the capacitor forming this low-pass filter. (For example, refer to Patent Document 1).

  In addition, an interleaved power supply circuit including a power factor correction circuit including a reactor, a diode, and a switching element and a smoothing capacitor is known. A configuration is also known in which the reactor is spatially disposed on the opposite side of the smoothing capacitor with the diode and the switching element to be cooled by the cooling jacket interposed therebetween. Such a configuration is introduced in Patent Document 3, for example.

  For later explanation, Patent Document 4 is cited as a prior art document disclosing a common mode choke.

JP 2014-096976 A Japanese Patent Laying-Open No. 2015-084737 Japanese Patent Laying-Open No. 2015-121364 JP, 2006-073025, A

  Indeed, the technique introduced in Patent Document 3 suppresses the complexity of the wiring pattern in the printed wiring board on which the power factor correction circuit and the smoothing capacitor are mounted. By arranging the weak electric component group and the high electric component group separately, the weak electric component is less likely to be adversely affected by the high electric component.

  However, in patent document 3, the control part which is a weak electrical component, and the reactor are not separated by the cooling jacket. Although there is no denial about the effect of heat dissipation from the reactor on the control unit, there is no indication that the effect is taken into account.

  Therefore, even if the cooling jacket introduced in Patent Document 3 can be applied in the vicinity of the power buffer circuit introduced in Patent Documents 1 and 2, a control unit that controls the inverter (or further power buffer circuit). It cannot be said that the influence of heat dissipation from the power buffer circuit is necessarily reduced. Since the power buffer circuit is connected between the converter and the inverter, the amount of heat released from the reactance element group (including the reactor and the capacitor) is high.

  Therefore, an object of the present invention is to reduce the influence of heat radiation from a reactance element group connected between a converter and an inverter on a control unit that controls the inverter.

  A power converter (201, 202) according to the present invention includes a converter (2) connected to an AC power source (1) for AC / DC conversion, and a DC power source line pair (LH) connected to the output side of the converter. , LL), a first capacitor (C4), a discharge circuit (42) for providing power to the pair of DC power lines by discharging the first capacitor, and a first reactor (L4), A charging circuit (41) for receiving electric power from the DC power supply line pair and charging the first capacitor (C4) with energy stored in the first reactor, and a first voltage ( Vdc) is DC / AC converted and an alternating current (Iu, Iv, Iw) is output to a load (6), a cooler (8) that cools at least the inverter, and the first capacitor The first An inverter control signal (S5) for controlling the inverter disposed on the opposite side via the cooler with respect to the reactance element group (J) connected between the converter and the inverter. And a control unit (109) for outputting.

  The influence of heat radiation from the reactance element connected between the converter and the inverter on the control unit that controls the inverter is reduced.

It is a circuit diagram which shows the power converter device concerning this embodiment. It is a top view which shows the power converter device concerning this embodiment. It is a schematic diagram which shows the freezing apparatus provided with the power converter device concerning this embodiment. It is a circuit diagram which shows partially the power converter device concerning the deformation | transformation of this embodiment. It is a top view which shows the power converter device concerning the deformation | transformation of this embodiment.

  FIG. 1 is a circuit diagram showing the electrical configuration and signal exchange of the power conversion device 201 according to this embodiment. In addition, since the detail of each part of this structure is disclosed by patent document 1, 2, for example, detailed description is omitted.

  In the circuit diagram, the power conversion device 201 includes a converter 2, a DC power supply line pair LH, LL, a charging circuit 41, a discharging circuit 42, an inverter 5, and a control unit 109. It can be said that the power converter 201 is the power converter with a power buffer described above.

  Converter 2 is connected to AC power supply 1 and performs AC / DC conversion. DC power supply line pair LH, LL is connected to the output side of converter 2.

  In FIG. 1, a diode bridge that performs full-wave rectification is illustrated as the converter 2. Specifically, the converter 2 includes diodes D21, D22, D23, and D24. The AC power supply 1 outputs a single-phase AC voltage Vin, and the diodes D21 to D24 convert the single-phase AC voltage Vin into a rectified voltage by single-phase full-wave rectification, and output this between the DC power supply line pair LH and LL. To do.

  The input side of the converter 2, that is, the single-phase AC voltage Vin is input at a pair of a connection point between the anode of the diode D 21 and the cathode of the diode D 22 and a connection point between the anode of the diode D 23 and the cathode of the diode D 24. is there.

  The output side of the converter 2, that is, the DC power supply line pair LH, LL is connected to the connection point between the cathode of the diode D21 and the cathode of the diode D23, and the connection point between the anode of the diode D22 and the anode of the diode D24. It is a pair. Specifically, the DC power supply line LH is connected to the former connection point, and the DC power supply line LL is connected to the latter connection point. Therefore, a higher potential than the DC power supply line LL is applied to the DC power supply line LH.

  The discharge circuit 42 includes a capacitor C4, and supplies power to the DC power supply line pair LH and LL by discharging the capacitor C4. Charging circuit 41 has a reactor L4, receives power from DC power supply line pair LH, LL, and stores energy in reactor L4. And the capacitor | condenser C4 is charged with the energy accumulate | stored in the reactor L4. The charging circuit 41 and the discharging circuit 42 constitute a power buffer circuit 4 that exchanges power between the DC power supply line pair LH and LL.

  It can be said that the reactor L4 and the capacitor C4 described above are components of a reactance element group connected between the converter 2 and the inverter 5.

  The charging circuit 41 further includes a switch Sl and a diode D40. Switch Sl is connected in series with reactor L4 between DC power supply line pair LH and LL. The switch S1 is realized by, for example, a transistor (here, IGBT (insulated gate bipolar transistor)). The diode D40 includes a cathode and an anode, and a charging current for charging the capacitor C4 flows. The cathode of the diode D40 is connected to the capacitor C4.

  Reactor L4 is connected between DC power supply line LH and the anode of diode D40. Switch Sl is connected between DC power supply line LL and the anode of diode D40. Such a configuration is known as a so-called boost chopper.

  A diode D41 is connected in reverse parallel to the transistor constituting the switch Sl. Here, the reverse parallel connection refers to a parallel connection in which the forward directions are opposite to each other. Specifically, the forward direction of the transistor that realizes the switch Sl is a direction from the DC power supply line LH to the DC power supply line LL, and the forward direction of the diode D41 is a direction from the DC power supply line LL to the DC power supply line LH. is there.

  Since the DC power supply line LH has a higher potential than the DC power supply line LL, basically no current flows through the diode D41. Therefore, the conduction / non-conduction of the switch S1 depends exclusively on that of the transistor realizing this. Therefore, the transistor and the diode D41 may be collectively regarded as the switch Sl.

  The discharge circuit 42 further includes a switch Sc. The switch Sc is connected in series with the capacitor C4 between the DC power supply line pair LH and LL. The switch Sc is connected to the DC power supply line LH side with respect to the capacitor C4. The switch Sc is realized by a transistor (here, IGBT), for example. A diode D42 is connected in reverse parallel to the transistor constituting the switch Sc. The forward direction of the transistor that realizes the switch Sc is a direction from the DC power supply line LL to the DC power supply line LH, and the forward direction of the diode D42 is a direction from the DC power supply line LH to the DC power supply line LL.

  Since the voltage vc supported by the capacitor C4 is boosted by the charging circuit 41, basically no current flows through the diode D42. Therefore, the conduction / non-conduction of the switch Sc depends exclusively on that of the transistor realizing this. Therefore, the transistor and the diode D42 may be collectively understood as the switch Sc.

  The inverter 5 receives the voltage Vdc output from the power buffer circuit 4 to the DC power supply line pair LH and LL, converts this to DC / AC, and outputs an AC current to the load 6. For example, the load 6 is a three-phase inductive load, and the inverter 5 outputs alternating currents Iu, Iv, and Iw.

  The inverter 5 has output terminals Pu, Pv, and Pw, and outputs alternating currents Iu, Iv, and Iw from these. The inverter 5 includes six switching elements Sup, Svp, Swp, Sun, Svn, and Swn. For example, IGBTs are employed for the switching elements Sup, Svp, Swp, Sun, Svn, and Swn.

  The switching elements Sup, Svp, Swp are respectively connected between the output terminals Pu, Pv, Pw and the DC power supply line LH, and the switching elements Sun, Svn, Swn are respectively connected to the output terminals Pu, Pv, Pw and the DC power supply line LL. Connected between. Inverter 5 constitutes a so-called voltage source inverter and includes six diodes.

  All of these diodes are connected in antiparallel to the switching elements Sup, Svp, Swp, Sun, Svn, and Swn with their cathodes facing the DC power supply line LH and their anodes facing the DC power supply line LL. .

  The control unit 109 includes a speed detection unit 9 and a control signal generation unit 10. For example, the load 6 is a compressor that compresses refrigerant, and the speed detector 9 detects AC currents Iu, Iv, and Iw, and the rotational angular speed ωm, q-axis current Iq, and d-axis current of the compressor determined from these. Id is given to the control signal generator 10.

  The control signal generator 10 further receives the amplitude Vm of the single-phase AC voltage Vin, the amplitude Im of the current flowing into the converter 2, the command value ω * of the electrical angular velocity ω, and the rotational angular velocity ωm, and controls the switches Sl and Sc, respectively. Switch control signals S41 and S42 to be output and an inverter control signal S5 to control the inverter 5 are output.

  In the power conversion device 201, although not essential, FIG. 1 illustrates a configuration including the low-pass filter 3. Low-pass filter 3 is interposed between the output side of converter 2 and DC power supply line pair LH, LL. The low-pass filter 3 includes a capacitor C3 and a reactor L3. Low-pass filter 3 transmits voltage v3 obtained by filtering the output voltage of converter 2 to DC power supply line pair LH, LL. However, the low-pass filter 3 has a function of not transmitting noise from the inverter 5 to the AC power supply 1 side, rather than having a smoothing function.

  Voltage v3 is supported by capacitor C3. It can be said that the charging circuit 41 boosts the voltage v3 and applies the voltage vc to the capacitor C4.

  Reactor L3 and capacitor C3 can be said to be a component of a reactance element group connected between converter 2 and inverter 5, together with reactor L4 and capacitor C4.

  When the low-pass filter 3 is provided in this way, the discharge circuit 42 further includes a current blocking element D43 in order to prevent discharge from the capacitor C4 to the capacitor C3 due to conduction of the switch Sc. Specifically, the current blocking element D43 is provided on the DC power supply line LH or the DC power supply line LL between the capacitors C3 and C4. The current blocking element D43 is realized by a diode, for example. In the illustration of FIG. 1, the diode is provided in the DC power supply line LH, and the forward direction is the direction from the converter 2 to the inverter 5.

  FIG. 2 is a plan view schematically showing a spatial arrangement of each part in the configuration of the power conversion device 201. The power conversion device 201 is disposed on the substrate 100, and FIG. 2 is a plan view taken along the thickness direction of the substrate 100. The substrate 100 extends along different directions Q1 and Q2 (here, directions Q1 and Q2 are illustrated as being orthogonal to each other).

  In FIG. 2, for the sake of simplicity, description of wirings connecting the elements included in the power conversion device 201 is omitted. For example, in FIG. 2, the DC power supply line pair LH, LL is omitted.

  In this configuration, the power conversion device 201 further includes a cooler 8 that is not described in FIG. 1 in addition to the components described in FIG. 1. The cooler 8 cools at least the inverter 5.

  The capacitor C4 includes three capacitors C41, C42, and C43. These, the capacitor C3, and the reactors L3 and L4 constitute a reactance element group J connected between the converter 2 and the inverter 5. The control unit 109 is arranged on the side opposite to the reactance element group J via the cooler 8. Specifically, the control unit 109, the cooler 8, and the reactance element group J are arranged in this order along the direction Q1.

  The cooler 8 also cools the configuration excluding the reactor L4 from the charging circuit 41, specifically, the set 41d of the switch Sl and the diode D40. The cooler 8 also cools the configuration in which the capacitor C4 is removed from the discharge circuit 42, specifically the switch Sc. When the discharge circuit 42 has the current blocking element D43, the cooler 8 also cools the current blocking element D43. In FIG. 2, assuming that the current blocking element D43 is provided, the switch Sc and the current blocking element D43 are shown as a set 42d.

  In the illustration of FIG. 2, the cooler 8 extends along the direction Q2. Capacitors C41, C42, C43, C3 and reactors L3, L4 also extend along direction Q2.

  When the power converter 201 employs such an arrangement, the cooler 8 exists between the reactor L4 of the charging circuit 41 and the capacitor C4 of the discharge circuit 42 and the control unit 109 in the power converter 201. Further, the inverter 5 is cooled by the cooler 8. Therefore, the cooler 8 can reduce the influence of heat radiation from the reactor L4 and the capacitor C4 to the control unit 109. In addition, since the inverter 5 is cooled by the cooler 8, it is possible to reduce the influence of the heat radiation from the inverter 5 on the control unit 109.

  In particular, since the cooler 8 also cools the set 41d, the heat radiation from the set 41d is also reduced from affecting the control unit 109.

  In particular, when the cooler 8 cools the switch Sc or the current blocking element D43, it is also possible to reduce the influence of heat radiation from these on the control unit 109.

  The cooler 8 has a cooling jacket 80 and inflow and outflow pipes 81 and 82. The inflow / outflow pipes 81 and 82 guide the inflow and outflow of the refrigerant to the cooling jacket 80.

  FIG. 3 is a schematic view illustrating the configuration of a refrigeration apparatus 300 including the power conversion device 201 and the load 6. In FIG. 3, the internal configuration of the power converter 201 is omitted except for the cooler 8. The load 6 provided in the refrigeration apparatus 300 is a compressor, and includes an electric motor 61 and a compression element 62. The compression element 62 is driven by the electric motor 61 to compress the refrigerant M. Refrigerant paths B1 and B2 are connected to the compression element 62, and refrigerant paths B4 and B3 are connected to the inflow and outflow pipes 81 and 82, respectively. The refrigeration apparatus 300 constitutes a heat pump unit.

  The refrigerant M flows into the compression element 62 via the refrigerant path B1, and flows out from the compression element 62 via the refrigerant path B2. The refrigerant M flows into the cooling jacket 80 via the refrigerant path B4 and the inflow / outflow pipe 81, and flows out from the cooling jacket 80 via the inflow / outflow pipe 82 and the refrigerant path B3.

  For example, a heat exchanger such as an evaporator or a condenser, or an evaporator may be provided between the refrigerant paths B1 and B2 and the refrigerant paths B3 and B4. In FIG. 3, the refrigerant path B2, the condenser, the expander, and the refrigerant path B4 are connected in this order, the refrigerant M flows in this order, the refrigerant path B3, the evaporator, and the refrigerant path B1 are connected in this order, and the refrigerant M is in this order. The case where it flows is illustrated.

  FIG. 4 is a circuit diagram partially showing an electrical configuration of the power conversion device 202 according to a modification of this embodiment. The power converter 202 has a configuration in which a common mode choke CMC is added to the power converter 201. The common mode choke CMC is interposed between the AC power source 1 and the converter 2 (see, for example, Patent Document 4). That is, the configuration of the power converter 202 on the inverter 5 side of the converter 2 electrically is the same as that of the power converter 201. Therefore, in FIG. 4, the illustration of the configuration on the inverter 5 side with respect to the converter 2 is omitted.

  FIG. 5 is a plan view schematically showing a spatial arrangement of each part in the configuration of the power conversion device 202. Except for the arrangement of the common mode choke CMC, the spatial arrangement of the power converter 202 is the same as the spatial arrangement of the power converter 201.

  The common mode choke CMC is disposed on the side opposite to the reactance element group J via the cooler 8. Specifically, the common mode choke CMC, the cooler 8, and the reactance element group J are arranged in this order along the direction Q1. Further, the common mode choke CMC and the control unit 109 are arranged in this order along the direction Q2.

  The common mode choke CMC has a lower heat dissipation than the reactance element group J, the inverter 5, and the sets 41d and 42d. Therefore, even if the common mode choke CMC and the control unit 109 are arranged on the same side with respect to the cooler 8, the control unit 109 is hardly affected by the heat generated from the common mode choke CMC.

  Of course, the refrigeration apparatus 300 including the power conversion apparatus 202 can be configured in the same manner as the power conversion apparatus 201 illustrated in FIG.

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Converter 3 Low pass filter 300 Refrigeration apparatus 5 Inverter 6 Load 8 Cooler 41 Charging circuit 41d Set 42 Discharge circuit 109 Control part 201,202 Power converter C3 2nd capacitor C4 1st capacitor CMC Common mode choke D40 Diode D43 Current blocking element Iu, Iv, Iw AC current J Reactance element group L3 Second reactor L4 First reactor LH, LL DC power line pair M Refrigerant S41 First switch control signal S42 Second switch control signal S5 Inverter control signal Sc Second Switch Sl first switch Vdc first voltage v3 second voltage

Claims (7)

A converter (2) connected to an AC power source (1) for AC / DC conversion;
DC power supply line pairs (LH, LL) connected to the output side of the converter;
A discharge circuit (42) having a first capacitor (C4), and supplying power to the pair of DC power supply lines by discharging the first capacitor;
A charging circuit (41) having a first reactor (L4), receiving electric power from the DC power line pair and charging the first capacitor (C4) with energy stored in the first reactor;
An inverter (5) for DC / AC conversion of the first voltage (Vdc) between the pair of DC power supply lines and outputting an alternating current (Iu, Iv, Iw) to the load (6);
A cooler (8) for cooling at least the inverter;
The reactance element group (J) including the first capacitor and the first reactor and connected between the converter and the inverter is arranged on the opposite side via the cooler to control the inverter A power converter (201, 202) comprising a control unit (109) that outputs an inverter control signal (S5). A common mode choke (CMC) interposed between the AC power source (1) and the converter (2) and disposed on the opposite side of the reactance element group (J) via the cooler
The power converter (202) of claim 1, further comprising: The charging circuit (41)
A first switch (Sl) connected in series with the first reactor (L4) between the DC power supply line pair (LH, LL);
A diode (D40) through which a charging current for charging the first capacitor (C4) flows;
The cooler (8) further cools the set (41d) including the first switch and the diode,
The power converter according to claim 1 or 2, wherein the control unit (109) further outputs a first switch control signal (S41) for controlling the first switch. The discharge circuit (42)
A second switch (Sc) connected in series with the first capacitor (C4) between the pair of DC power supply lines
Further comprising
The cooler (8) further cools the second switch;
The said control part (109) is a power converter device as described in any one of Claim 1 thru | or 3 which further outputs the 2nd switch control signal (S42) which controls the said 2nd switch. A second capacitor (C3) and a second reactor (L3) are interposed between the output side of the converter (2) and the DC power supply line pair (LH, LL), both of which are included in the reactance element group (J). And a low-pass filter (3) for transmitting a second voltage (v3) obtained by filtering the output voltage of the converter to the DC power supply line pair
Further comprising
The discharge circuit (42)
A current blocking element (D43) for blocking current from the first capacitor toward the low-pass filter (3);
Further comprising
The power converter according to any one of claims 1 to 4, wherein the cooler (8) further cools the current blocking element.   The power converter according to any one of claims 1 to 5, wherein a refrigerant (M) compressed by the load (6) flows through the cooler (8). The power conversion device (201, 202) according to claim 6,
Comprising the load (6),
The load is a refrigeration apparatus (300) that is a compressor that compresses the refrigerant (M).

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