JP6811762B2 - Power conversion device and refrigeration cycle device equipped with this - Google Patents

Description

The present invention relates to a power conversion device and the like.

Power conversion devices such as inverters that drive motors are known. The inverter supplies electric power to the motor, which is a load, by performing the switching operation of the semiconductor switching element. Further, the switching operation causes a current change in the wiring connecting the semiconductor switching element and the DC power supply, and a counter electromotive force is generated by the parasitic inductance on the wiring.

As a result, when the current of the semiconductor switching element is cut off, a voltage obtained by combining the counter electromotive force and the power supply voltage described above is applied to the semiconductor switching element. The period during which the counter electromotive force is generated is extremely short as compared with the switching pulse width of the semiconductor switching element, and the voltage waveform thereof becomes spike-shaped. Therefore, the voltage of the semiconductor switching element has a waveform in which a spike-shaped voltage (hereinafter, referred to as “spike voltage”) is superimposed on the power supply voltage. In order to prevent the semiconductor switching element from being destroyed by such a spike voltage, a semiconductor switching element having a withstand voltage higher than the combined voltage value of the power supply voltage and the spike voltage is usually used.

It should be noted that there is generally a proportional relationship between the withstand voltage of the semiconductor switching element and its on-voltage and on-resistance. Therefore, if a switching element having a high withstand voltage is used to prevent destruction due to the spike voltage, the power loss increases. Furthermore, the spike voltage promotes the generation of electromagnetic noise, which may induce malfunction of the device. As a technique for reducing such a spike voltage, for example, the one described in Patent Document 1 is known.

That is, Patent Document 1 states that "the first plate-shaped conductor and the second plate-shaped conductor, in a laminated state with an insulator, project from the surface of the resin seal and cross the side portion of the drive control circuit, and further, the first A power conversion device having a configuration in which the tip of each of the plate-shaped conductor and the second plate-shaped conductor is connected to the electrode of the power module is described.

Japanese Unexamined Patent Publication No. 2011-239679

By the way, a snubber capacitor is known as an element that reduces back electromotive force due to parasitic inductance. In order to effectively reduce the back electromotive force by using this snubber capacitor, it is desirable to mount the snubber capacitor in the vicinity of the semiconductor switching element.

However, due to restrictions such as the shape and mounting method of the semiconductor switching element, it may not be possible to arrange the snubber capacitor in the vicinity of the semiconductor switching element. Even in such a case, it is required to reduce the power loss and electromagnetic noise associated with the counter electromotive force, but Patent Document 1 does not describe such a technique.

Therefore, an object of the present invention is to provide a power conversion device or the like that reduces power loss and electromagnetic noise.

In order to solve the above problems, the present invention comprises a first conductor pattern connected to each of the positive electrode side and the negative electrode side of the power conversion circuit to form a part of a DC power supply line, and the power conversion circuit and a snubber capacitor. It has a second conductor pattern connected on each of the positive electrode side and the negative electrode side, and is located on the positive electrode side so as to be close to the first conductor pattern on the positive electrode side in the vicinity of the input terminal on the positive electrode side of the power conversion circuit. The second conductor pattern is provided, and the second conductor pattern on the negative electrode side is provided near the input terminal on the negative electrode side of the power conversion circuit so as to be close to the first conductor pattern on the negative electrode side. And said.

According to the present invention, it is possible to provide a power conversion device or the like that reduces power loss and electromagnetic noise.

It is a block diagram which includes the power conversion apparatus which concerns on 1st Embodiment of this invention. It is explanatory drawing which includes the equivalent circuit of the parasitic inductance reducing means provided in the power conversion apparatus which concerns on 1st Embodiment of this invention. It is a top view and the side view which shows the arrangement of the main electronic components mounted on the printed wiring board of the power conversion apparatus which concerns on 1st Embodiment of this invention. It is explanatory drawing which shows the conductor pattern of the component surface of the printed wiring board provided in the power conversion apparatus which concerns on 1st Embodiment of this invention. It is explanatory drawing when the conductor pattern of the solder surface of the printed wiring board provided in the power conversion apparatus which concerns on 1st Embodiment of this invention is seen through from the component surface side. FIG. 2 is a cross-sectional view taken along the line II-II in FIGS. 4A and 4B in the power conversion device according to the first embodiment of the present invention. It is explanatory drawing of the current waveform when any semiconductor switching element of the power conversion circuit included in the power conversion apparatus which concerns on 1st Embodiment of this invention transitions from on to off. It is explanatory drawing which shows the conductor pattern of the component surface of the printed wiring board provided in the power conversion apparatus which concerns on 2nd Embodiment of this invention. It is explanatory drawing which shows the current flow in the conductor pattern of the component surface of the printed wiring board provided in the power conversion apparatus which concerns on 2nd Embodiment of this invention. It is explanatory drawing which includes the equivalent circuit of the parasitic inductance reducing means provided in the power conversion apparatus which concerns on 3rd Embodiment of this invention. It is explanatory drawing which shows the conductor pattern of the component surface of the printed wiring board provided in the power conversion apparatus which concerns on 3rd Embodiment of this invention. It is explanatory drawing when the conductor pattern of the solder surface of the printed wiring board provided in the power conversion apparatus which concerns on 3rd Embodiment of this invention is seen through from the component surface side. It is a block diagram of the air conditioner which concerns on 4th Embodiment of this invention. It is explanatory drawing which shows an example of the voltage waveform of the semiconductor switching element provided in the power conversion apparatus which concerns on a comparative example. It is a top view which shows the arrangement of the composite snubber capacitor provided in the power conversion apparatus which concerns on a comparative example.

<< First Embodiment >>
<Configuration of power converter>
FIG. 1 is a configuration diagram including a power conversion device 100 according to the first embodiment.
The power conversion device 100 shown in FIG. 1 is an inverter that converts DC power input from the DC power supply E into three-phase AC power and outputs the three-phase AC power to the motor M. As the DC power source E shown in FIG. 1, an AC power source (not shown) and a converter that performs AC / DC conversion (not shown) may be used.

As shown in FIG. 1, the input side of the power conversion device 100 is connected to the positive electrode of the DC power supply E via the positive electrode side power supply line P (DC power supply line), and the negative electrode side power supply line N (DC power supply line). It is connected to the negative electrode of the DC power supply E via. Then, a DC voltage is applied to the input side of the power conversion circuit 30 via the above-mentioned "DC power supply line". The positive electrode side power supply line P and the negative electrode side power supply line N are wirings including a copper foil pattern, electric wires, and the like of the printed wiring board 60 (see FIG. 3).

As shown in FIG. 1, the positive electrode side power supply line P contains a parasitic inductance Lp, and the negative electrode side power supply line N contains a parasitic inductance Ln. The parasitic inductances Lp and Ln are widely distributed in the positive electrode side power supply line P and the negative electrode side power supply line N (that is, the DC power supply line) and are not concentrated in one place, but in FIG. For convenience, they are shown as parasitic inductances Lp and Ln.

As shown in FIG. 1, the power conversion device 100 includes a smoothing capacitor 10, a parasitic inductance reducing means 20, a power conversion circuit 30, current detecting means 41 and 42, and a control means 50.

The smoothing capacitor 10 is a capacitor that smoothes the voltage (pulsating DC voltage) applied from the DC power supply E. The positive electrode of the smoothing capacitor 10 is connected to the positive electrode side power supply line P, and the negative electrode is connected to the negative electrode side power supply line N.

The parasitic inductance reducing means 20 reduces the parasitic inductance of the wiring including the positive electrode side power supply line P and the negative electrode side power supply line N. Although details will be described later, the parasitic inductance reducing means 20 includes a snubber capacitor 21 and the like (see FIG. 2). As shown in FIG. 1, the input side of the parasitic inductance reducing means 20 is connected to the positive electrode side power supply line P and also to the negative electrode side power supply line N. On the other hand, the output side of the parasitic inductance reducing means 20 is connected to the power conversion circuit 30.

The power conversion circuit 30 is a three-phase inverter circuit, which converts a DC voltage (DC power) into a U-phase, V-phase, and W-phase three-phase AC voltage (three-phase AC power), and converts the three-phase AC voltage into a motor. Apply to M. As shown in FIG. 1, the power conversion circuit 30 includes six semiconductor switching elements 31 to 36. As such semiconductor switching elements 31 to 36, for example, an IGBT (Insulated Gate Bipolar Transistor) is used. The on / off of the semiconductor switching elements 31 to 36 is controlled by the control means 50.

The semiconductor switching elements 31 and 32 form a leg and convert a DC voltage into a U-phase AC voltage. Further, the semiconductor switching elements 33 and 34 form another leg and convert the DC voltage into the V-phase AC voltage. Further, the semiconductor switching elements 35 and 36 form yet another leg, and convert the DC voltage into the W-phase AC voltage. These three legs are connected in parallel and are connected to the motor M, which is a load, via U-phase, V-phase, and W-phase wiring. The motor M is driven by the three-phase AC voltage applied from the power conversion circuit 30.

As shown in FIG. 1, a freewheeling diode D is connected to each of the semiconductor switching elements 31 to 36. A MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) may be used as the semiconductor switching element instead of the IGBT. In that case, a parasitic diode (not shown) formed at the pn junction existing between the source and drain of the MOSFET can be used as an alternative to the above-mentioned freewheeling diode D.

The current detecting means 41 detects the current in the U-phase wiring among the U-phase, V-phase, and W-phase wirings. Another current detecting means 42 detects the current in the W-phase wiring. The detected values of the current detecting means 41 and 42 are output to the control means 50 described below, respectively.

The control means 50 is, for example, a microcomputer, and although not shown, the control means 50 includes electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces. Has been done. Then, the program stored in the ROM is read out and expanded in the RAM, and the CPU executes various processes.

The control means 50 is a semiconductor switching element 31 to drive the motor M at a predetermined rotation speed and torque based on the voltage between the positive electrode and the negative electrode of the smoothing capacitor 10 and the detected values of the current detecting means 41 and 42. 36 is controlled. Next, the spike voltage associated with the switching of the semiconductor switching elements 31 to 36 will be briefly described.

<About spike voltage>
FIG. 11 is an explanatory diagram showing an example of a voltage waveform of a semiconductor switching element included in the power conversion device according to the comparative example.
The power conversion device (not shown) according to the comparative example is the same as the power conversion device 100 (see FIG. 1) of the present embodiment except that the parasitic inductance reducing means 20 (see FIG. 1) is not provided. It is assumed that the configuration is.

In the comparative example, as the semiconductor switching elements 31 to 36 are switched, a back electromotive force is generated in the wiring connecting the semiconductor switching elements 31 to 36 and the DC power supply E. Then, a voltage obtained by combining the counter electromotive force and the power supply voltage described above is applied to the semiconductor switching elements 31 to 36. That is, as shown in FIG. 11, the voltage of the waveform of the predetermined spike voltage V _S is superimposed on the power source voltage V _E is applied to the semiconductor switching elements 31 to 36.

Therefore, in this embodiment, by providing the snubber capacitor 21 parasitic inductance reducing means 20 comprise (see FIG. 2) (see FIG. 2), so as to suppress the reverse electromotive force caused by the parasitic inductance (spike voltage V _S) ing.

<Means for reducing parasitic inductance>
FIG. 2 is an explanatory diagram including an equivalent circuit of the parasitic inductance reducing means 20 included in the power conversion device 100.
As shown in FIG. 2, the parasitic inductance reducing means 20 includes a snubber capacitor 21, a first conductor pattern k1, h1, and a second conductor pattern k2, h2.

The snubber capacitor 21 is a capacitor for suppressing back electromotive force due to parasitic inductance, and is mounted on a printed wiring board 60 (see FIG. 3) described later. The snubber capacitor 21 is connected to the input side of the power conversion circuit 30. More specifically, the positive electrode of the snubber capacitor 21 is connected to the input terminal IP on the positive electrode side of the power conversion circuit 30 via the second conductor pattern k2. On the other hand, the negative electrode of the snubber capacitor 21 is connected to the input terminal IN on the negative electrode side of the power conversion circuit 30 via the second conductor pattern h2.

The first conductor pattern k1 is a conductor pattern mounted on the printed wiring board 60 (see FIG. 3) as a part of the positive electrode side power supply line P (DC power supply line). As shown in FIG. 2, the first conductor pattern k1 is connected to the input terminal IP on the positive electrode side of the power conversion circuit 30.
The other first conductor pattern h1 is a conductor pattern mounted on the printed wiring board 60 (see FIG. 3) as a part of the negative electrode side power supply line N (DC power supply line). As shown in FIG. 2, the first conductor pattern h1 is connected to the input terminal IN on the negative electrode side of the power conversion circuit 30.
As described above, the printed wiring board 60 (see FIG. 3) has first conductor patterns k1 and h1 which are connected to the positive electrode side and the negative electrode side of the power conversion circuit 30 and form a part of the “DC power supply line”. doing.

The positive electrode side power supply line P for connecting the positive electrode of the DC power supply E (see FIG. 1) and the power conversion circuit 30 includes the first conductor pattern k1, and the positive electrode of the DC power supply E and the printed wiring board 60 ( (Not shown) is included. The same applies to the negative electrode side power supply line N.

As described above, the second conductor pattern k2 is a conductor pattern that connects the power conversion circuit 30 and the snubber capacitor 21 on the positive electrode side, and is mounted on the printed wiring board 60 (see FIG. 3). The other second conductor pattern h2 is a conductor pattern that connects the power conversion circuit 30 and the snubber capacitor 21 on the negative electrode side as described above, and is mounted on the printed wiring board 60 (see FIG. 3).
As described above, the printed wiring board 60 (see FIG. 3) has second conductor patterns k2 and h2 for connecting the power conversion circuit 30 and the snubber capacitor 21 on the positive electrode side and the negative electrode side, respectively. The parasitic inductances La1, Lb1, La2, Lb2 and the like shown in FIG. 2 will be described later.

FIG. 3 is a plan view and a side view showing the arrangement of main electronic components mounted on the printed wiring board 60 of the power conversion device 100.
The upper view of FIG. 3 is a plan view of the printed wiring board 60 and the like. On the other hand, the lower view of FIG. 3 is a side view of the printed wiring board 60 and the like.
In the example shown in FIG. 3, the power conversion device 100 is configured as a board set in which the printed wiring board 60 and the radiator 70 are combined. The substrate assembly (that is, the power conversion device 100) described above is often used in a state of being housed in a predetermined case (not shown).

Further, the power conversion circuit 30 is configured as a semiconductor module in which the semiconductor switching elements 31 to 36 (see FIG. 1) are housed in one package. The power conversion circuit 30 is arranged between the printed wiring board 60 and the radiator 70 in a state of being fixed to the radiator 70.

As shown in FIG. 3, the power conversion circuit 30 includes terminals IP, IN, IU, IV, and IW for electrically connecting itself and the printed wiring board 60. Each of these terminals IP, IN, IU, IV, and IW extends upward toward the printed wiring board 60, and has a predetermined conductor pattern mounted on the component surface and the solder surface of the printed wiring board 60 and electrical. It is connected to the. Such a configuration is also included in the matter that the power conversion circuit 30 is "mounted" on the printed wiring board 60. The "component surface" is a surface on the printed wiring board 60 on which electronic components such as a smoothing capacitor 10 (see FIG. 3) are mounted. In the present embodiment, the "part surface" and the "solder surface" on the back surface thereof are "pattern layers" (layers on which a conductor pattern or the like is provided).

The input terminal IP is connected to the first conductor pattern k1 on the positive electrode side mounted on the printed wiring board 60 (not shown in FIG. 3, see FIG. 2).
The input terminal IN is connected to the first conductor pattern h1 on the negative electrode side mounted on the printed wiring board 60 (not shown in FIG. 3, see FIG. 2).

The terminal IU is connected to the U-phase wiring (see FIG. 1) of the motor M (see FIG. 1). Similarly, the terminals IV and IW are connected to the V-phase and W-phase wirings of the motor M, respectively.

In addition, the smoothing capacitor 10 and the snubber capacitor 21 included in the parasitic inductance reducing means 20 (see FIG. 2) are mounted on the printed wiring board 60. The smoothing capacitor 10 and the snubber capacitor 21 are electrically connected to the power conversion circuit 30 via a predetermined copper foil pattern provided on the printed wiring board 60. In the example shown in FIG. 3, the snubber capacitor 21 is arranged between the smoothing capacitor 10 and the power conversion circuit 30 in a plan view.

The radiator 70 is a heat sink for dissipating heat from the power conversion circuit 30. The radiator 70 includes a plate-shaped portion 71 and a plurality of fins 72 extending downward from the plate-shaped portion 71. The radiator 70 is fixed to the power conversion circuit 30 via screws Ga and Gb.
When tightening or loosening the screws Ga and Gb using a tool (not shown), screw holes Ha and Hb into which the tool is inserted are provided in the printed wiring board 60. That is, screw holes Ha and Hb are provided at positions corresponding to the screws Ga and Gb on the printed wiring board 60. Further, screw holes (not shown) are also provided at the four corners of the printed wiring board 60, respectively. Four screws Gc inserted through these screw holes are screwed into the radiator 70 via the spacer Sc.

Considering that the power conversion circuit 30 is removed from the radiator 70 during maintenance, it is desirable that the snubber capacitor 21 is mounted at a position separated from the screw holes Ha and Hb as shown in FIG. Due to such restrictions, it may be difficult to arrange the snubber capacitor 21 in the vicinity of the power conversion circuit 30. Specifically, the snubber capacitor 21 may not be arranged in the vicinity of the input terminals IP and IN on the DC side of the power conversion circuit 30.

A driver circuit or the like (not shown) for driving the switching elements 31 to 36 is mounted in the region between the screw holes Ha and Hb in the left-right direction of the component surface of the printed wiring board 60. Therefore, it is often difficult to mount the snubber capacitor 21 in this region.

If the parasitic inductance of the conductor pattern connecting the snubber capacitor 21 and the input terminals IP and IN is not reduced, a predetermined spike voltage is generated (see FIG. 11). As a result, power loss may increase and electromagnetic noise may occur. In order to reduce such spike voltage and electromagnetic noise, the parasitic inductance reducing means 20 (see FIGS. 4A and 4B) is provided in the present embodiment.

FIG. 4A is an explanatory diagram showing a conductor pattern on the component surface of the printed wiring board 60 included in the power conversion device (see also FIGS. 2 and 3 as appropriate).
In FIG. 4A, in the first conductor patterns k1 and h1, the portion that is actually hidden by the snubber capacitor 21 and cannot be seen is also seen through.

The first conductor patterns k1 and h1 shown in FIG. 4A are wirings for connecting the DC power supply E (see FIG. 1) and the power conversion circuit 30 as described above. The terminal 21a of the snubber capacitor 21 is inserted through the hole fk of the first conductor pattern k1. A predetermined distance is provided between the peripheral edge of the hole fk and the terminal 21a. The same applies to the other first conductor pattern h1. Therefore, the first conductor patterns k1 and h1 and the snubber capacitor 21 are not electrically connected on the component surface of the printed wiring board 60. The through holes jk and jh will be described later.

FIG. 4B is an explanatory view when the conductor pattern on the solder surface of the printed wiring board 60 included in the power conversion device is seen through from the component surface side.
The "solder surface" is a surface (the surface on the back side of the component surface) to be soldered on the printed wiring board 60, and faces the radiator 70 (see FIG. 3). Further, in FIG. 4B, when the printed wiring board 60 is viewed from the component surface side, the first conductor patterns k1a and h1a and the second conductor patterns k2 and h2 on the solder surface side, which are not actually visible, are seen through and shown by broken lines. It is shown in the figure.

The first conductor pattern k1a on the solder surface side shown in FIG. 4B is electrically connected to the first conductor pattern k1 (see FIG. 4A) on the component surface side via a through hole jk. Similarly, the first conductor pattern h1a on the solder surface side is electrically connected to the first conductor pattern h1 (see FIG. 4A) on the component surface side via a through hole jh.

The first conductor pattern k1 on the component surface side and the first conductor pattern k1a on the solder surface side are both electrically connected to the positive electrode of the smoothing capacitor 10 (see FIG. 3). Similarly, the other first conductor patterns h1 and h1a are electrically connected to the negative electrode of the smoothing capacitor 10. In this way, the DC power supply E (see FIG. 1) and the power conversion circuit 30 are electrically connected using both the component side and the solder side of the printed wiring board 60. As a result, the electrical resistance of the first conductor patterns k1 and h1 which are the "DC power supply lines" can be reduced, and thus the power loss can be reduced.

The second conductor patterns k2 and h2 are wirings that connect the snubber capacitor 21 and the power conversion circuit 30 as described above. Then, in the vicinity of the input terminal IP on the positive electrode side of the power conversion circuit 30, the second conductor pattern k2 on the positive electrode side (see FIG. 4B) is provided so as to be close to the first conductor pattern k1 on the positive electrode side (see FIG. 4A). Has been done. That is, the first conductor pattern k1 and the second conductor pattern k2 are close to each other with the insulating layer 60s (see FIG. 5) of the printed wiring board 60 in between.

Similarly, in the vicinity of the input terminal IN on the negative electrode side of the power conversion circuit 30, the second conductor pattern h2 on the negative electrode side (see FIG. 4B) is placed close to the first conductor pattern h1 on the negative electrode side (see FIG. 4A). It is provided. That is, the first conductor pattern h1 and the second conductor pattern h2 are close to each other with the insulating layer 60s (see FIG. 5) of the printed wiring board 60 in between.

Here, returning to FIG. 2, the parasitic inductance reducing means 20 will be described in detail. In FIG. 2, the first conductor patterns k1a and h1a (see FIG. 4B) of the printed wiring board 60 are shown as being included in the first conductor patterns k1 and h1.
The parasitic inductance Lp shown in FIG. 2 is the parasitic inductance of the portion from the DC power supply E (see FIG. 1) to the through hole jk (see FIG. 4A) in the first conductor pattern k1 (see FIG. 4A).

Further, the parasitic inductance La1 is a parasitic inductance of a portion of the first conductor pattern k1 (see FIG. 4A) that overlaps with the second conductor pattern k2 (see FIG. 4B) in a plan view. Further, the parasitic inductance La2 is the parasitic inductance of the second conductor pattern k2. The same applies to the parasitic inductances Ln and Lb1 of the first conductor pattern h1 on the negative electrode side and the parasitic inductance Lb2 of the second conductor pattern h2.

FIG. 5 is a cross-sectional view taken along the line II-II in FIGS. 4A and 4B.
The direction of the current when any of the semiconductor switching elements 31 to 36 (see FIG. 1) transitions from on to off and the current to the input terminal IP on the DC side is decreasing is indicated by an arrow in FIG. Shown. Further, the direction of the magnetic flux in the first conductor pattern k1 and the second conductor pattern k2 is indicated by another arrow.

As described above, the first conductor pattern k1 and the second conductor pattern k2 are in a state of being close to each other with the insulating layer 60s of the printed wiring board 60 interposed therebetween and magnetically coupled to each other. For example, when a magnetic field simulation was performed using a printed wiring board 60 having a thickness of the insulating layer 60s of 1.5 mm, the coupling coefficient between the first conductor pattern k1 and the second conductor pattern k2 was about 0.8. Yes, it was a relatively high value. The same applies to the first conductor pattern h1 and the second conductor pattern h2 on the negative electrode side. Next, the operation of the parasitic inductance reducing means 20 by the magnetic coupling described above will be described.

FIG. 6 is an explanatory diagram of a current waveform when any of the semiconductor switching elements of the power conversion circuit included in the power conversion device transitions from on to off (see FIGS. 2 and 5 as appropriate).
The horizontal axis of FIG. 6 is time, and the vertical axis is the current value.
The current I _DC shown in FIG. 6 (and FIG. 2) is the current flowing through the first conductor pattern k1. Further, the current I _{INV_IN} is a current flowing through the input terminal IP on the DC side of the power conversion circuit 30. The current I _SC is a current flowing through the positive electrode of the second conductor pattern k2 or the snubber capacitor 21.

From time t0 to immediately before time t1 shown in FIG. 6, the semiconductor switching elements 31 to 36 (see FIG. 1) of the power conversion circuit 30 are on or off, and the current I _DC and the current I _{INV_IN} are substantially constant. The current value is Ia. On the other hand, from time t0 immediately before the time t1, since the snubber capacitor 21 current _{I SC} does not flow, the value of the current _{I SC} is zero.

When any of the semiconductor switching elements 31 to 36 transitions from on to off at time t1, the current I _{INV_IN} decreases. _Along with this, the current I _DC also _starts to decrease, but the decrease rate of the current I _DC is smaller than that of the current I _{INV_IN} due to the parasitic inductances Lp and La1 (see FIG. 2) of the first conductor pattern k1. Then, the current I _SC corresponding to the difference between the current I _{INV_IN} and the current I _DC flows to the positive electrode of the snubber capacitor 21 via the second conductor pattern k2.

From the above operation, currents in opposite directions flow in the first conductor pattern k1 and the second conductor pattern k2 shown in FIG. As a result, the magnetic flux generated in the first conductor pattern k1 and the magnetic flux generated in the second conductor pattern k2 cancel each other out, and the overall inductance values of the first conductor pattern k1 and the second conductor pattern k2 are reduced. To. As a result, the snubber capacitor 21 functions effectively, and the counter electromotive force (spike voltage) associated with the parasitic inductance is reduced.
The same effect is exerted on the first conductor pattern h1 (see FIG. 2) and the second conductor pattern h2 (see FIG. 2) on the negative electrode side.

<Effect>
According to the first embodiment, currents in opposite directions flow in the first conductor pattern k1 and the second conductor pattern k2 that are close to each other with the insulating layer 60s of the printed wiring board 60 interposed therebetween (see FIG. 5). As a result, the magnetic flux generated in the first conductor pattern k1 and the magnetic flux generated in the second conductor pattern k2 are canceled, so that the counter electromotive force (spiked voltage) associated with the parasitic inductance is reduced. The same applies to the first conductor pattern h1 and the second conductor pattern h2 on the negative electrode side.

As a result, semiconductor switching elements 31 to 36 having a low withstand voltage can be used. In addition, there is generally a proportional relationship between the withstand voltage of the semiconductor switching elements 31 to 36 and the on-resistance thereof. Therefore, by using the semiconductor switching elements 31 to 36 having a low withstand voltage, the power loss in the power conversion circuit 30 can be reduced. As described above, according to the first embodiment, it is possible to provide the power conversion device 100 in which the power loss and the electromagnetic noise are reduced.

Further, since the power loss in the power conversion circuit 30 is reduced, a radiator 70 having a relatively small size can be used. Therefore, according to the first embodiment, the power conversion device 100 including the radiator 70 can be miniaturized.

<< Second Embodiment >>
The second embodiment is different from the first embodiment in that predetermined conductor patterns k and h (see FIG. 7A) are mounted on one side of the printed wiring board 60A (see FIG. 7A). Others are the same as those in the first embodiment. Therefore, a part different from the first embodiment will be described, and a description of the overlapping part will be omitted.

FIG. 7A is an explanatory diagram showing conductor patterns k and h on the component surface of the printed wiring board 60A included in the power conversion device.
As shown in FIG. 7A, the parasitic inductance reducing means 20A includes a conductor pattern k on the positive electrode side, a conductor pattern h on the negative electrode side, and a snubber capacitor 21. The conductor pattern k on the positive electrode side includes a first conductor pattern k1 (see FIG. 7B) and a second conductor pattern k2 (see FIG. 7B). The same applies to the conductor pattern h on the negative electrode side. These conductor patterns k and h have a predeterminedly bent shape in a plan view, and are provided on one side (component side) of the printed wiring board 60A.

FIG. 7B is an explanatory diagram showing a current flow in conductor patterns k and h on the component surface of the printed wiring board 60A included in the power conversion device.
In addition to showing the direction in which the current flows as an arrow in FIG. 7B, reference numerals indicating the first conductor patterns k1 and h1 and the second conductor patterns k2 and h2 are shown. Further, in order to make the reference numerals in FIG. 7B easier to see, the snubber capacitor 21 (see FIG. 7A) and the power conversion circuit 30 (see FIG. 7A) are not shown. Other than that, FIG. 7B is the same as FIG. 7A.

In the example shown in FIG. 7B, the first conductor pattern k1 on the positive electrode side extends in a straight line in the vicinity of the input terminal IP. On the other hand, the second conductor pattern k2 on the positive electrode side is provided side by side in parallel with the first conductor pattern k1 and is close to the first conductor pattern k1. A predetermined gap is provided between the first conductor pattern k1 and the second conductor pattern k2. As a result, the first conductor pattern k1 and the second conductor pattern k2 are magnetically coupled.

As described above, the printed wiring board 60A has one pattern layer (conductor pattern on the component surface side), and the first conductor pattern k1 and the second conductor pattern k2 are provided side by side with the above-mentioned pattern layer. There is. The same applies to the first conductor pattern h1 and the second conductor pattern h2 on the negative electrode side.

Further, the end of the first conductor pattern k1 on the input terminal IP side and the end of the second conductor pattern k2 on the input terminal IP side are electrically connected. Then, when any of the semiconductor switching elements 31 to 36 transitions from on to off, a current flows so as to fold back through the first conductor pattern k1 and the second conductor pattern k2 (see the arrow in FIG. 7B). ). Therefore, currents in opposite directions flow through the first conductor pattern k1 and the second conductor pattern k2.

As a result, the magnetic flux in the first conductor pattern k1 and the magnetic flux in the second conductor pattern k2 cancel each other out. That is, the parasitic inductance when the first conductor pattern k1 and the second conductor pattern k2 are viewed as a whole is reduced. The same can be said for the first conductor pattern h1 and the second conductor pattern h2 on the negative electrode side.

<Effect>
According to the second embodiment, currents in opposite directions flow in the first conductor pattern k1 and the second conductor pattern k2 provided on the component surface of the printed wiring board 60A. As a result, the counter electromotive force (spike voltage) associated with the parasitic inductance is reduced.

Further, in the second embodiment, the first conductor patterns k1 and h1 and the second conductor patterns k2 and h2 are provided on the component side (one side) of the printed wiring board 60A. In general, a printed wiring board 60A having a conductor pattern on only one side is cheaper than a printed wiring board 60A having a conductor pattern on both sides. Therefore, according to the second embodiment, the cost of the power conversion device can be reduced as compared with the first embodiment.

<< Third Embodiment >>
The third embodiment is different from the first embodiment in that the power conversion device 100B (see FIG. 8) includes two snubber capacitors 22 and 23 (see FIG. 8). Others are the same as those in the first embodiment. Therefore, a part different from the first embodiment will be described, and a description of the overlapping part will be omitted.

FIG. 8 is an explanatory diagram including an equivalent circuit of the parasitic inductance reducing means 20B included in the power conversion device.
As shown in FIG. 8, the parasitic inductance reducing means 20B includes two snubber capacitors 22 and 23 connected in parallel. The positive electrodes of the snubber capacitors 22 and 23 are connected to the input terminal IP via the second conductor pattern k2. On the other hand, the negative electrodes of the snubber capacitors 22 and 23 are connected to the input terminal IN via the second conductor pattern h2. That is, the power conversion circuit 30 and the snubber capacitors 22 and 23 are connected on the positive electrode side and the negative electrode side, respectively, via the second conductor patterns k2 and h2.

Further, although not shown, inside the snubber capacitors 22 and 23, there is an internal wiring connecting the dielectric and the external electrode, and a parasitic inductance exists on the internal wiring. This reduction in the parasitic inductance of the internal wiring is effective in reducing the spike voltage as well as the reduction in the parasitic inductance of the conductor pattern. Therefore, in the second embodiment, the two snubber capacitors 22 and 23 are connected in parallel so that their parasitic inductances are also connected in parallel in an equivalent manner. As a result, the overall parasitic inductance of the snubber capacitors 22 and 23 is reduced, so that the effect of reducing the spike voltage is further enhanced.

The above-mentioned parallel-connected snubber capacitors 22 and 23 are defined as "composite snubber capacitors". Next, problems when such a "composite snubber capacitor" is provided will be briefly described.

FIG. 12 is a plan view showing the arrangement of the composite snubber capacitor T included in the power conversion device according to the comparative example.
The white arrows shown in FIG. 12 indicate the direction of the cooling air for cooling the circuit components of the power converter. A fan F for sending cooling air may be installed on the printed wiring board 60.
The broken line arrow shown in FIG. 12 indicates the arrangement direction of the snubber capacitors 22 and 23 included in the composite snubber capacitor T. In this comparative example, the direction of the cooling air, the direction of the DC feeding line (not shown in FIG. 12), and the arrangement direction of the snubber capacitors 22 and 23 are all substantially parallel.

Further, when viewed from the windward side of the cooling air, one snubber condenser 23 is hidden by the other snubber condenser 22. In such an arrangement, the snubber condenser 22 on the leeward side is more likely to be cooled, while the snubber condenser 23 on the leeward side is more likely to generate heat. As a result, the life of the snubber capacitor 23 on the leeward side is shorter than that of the snubber capacitor 22 on the leeward side. In consideration of such a problem, in the third embodiment, the two snubber capacitors 22 and 23 are arranged as follows.

FIG. 9A is an explanatory diagram showing a conductor pattern on the component surface of the printed wiring board 60 included in the power conversion device according to the third embodiment.
The parasitic inductance reducing means 20B shown in FIG. 9A includes first conductor patterns k1 and h1, second conductor patterns k2 and h2 (see FIG. 9B), and snubber capacitors 22 and 23.

The snubber capacitors 22 and 23 each have an elongated rectangular shape (that is, a flat shape) in a plan view, and are mounted on the printed wiring board 60.
The first conductor patterns k1 and h1 are wirings that connect the DC power supply E (see FIG. 1) and the power conversion circuit 30. In the first conductor patterns k1 and h1, notches f are provided at locations corresponding to the terminals of the snubber capacitors 22 and 23, respectively. Therefore, the first conductor patterns k1 and h1 and the snubber capacitors 22 and 23 are not electrically connected on the component surface of the printed wiring board 60.

As shown in FIG. 9A, the arrangement direction (broken line arrow) of the snubber capacitors 22 and 23 and the direction in which the first conductor patterns k1 and h1 extend are perpendicular to each other. Further, the arrangement directions of the snubber capacitors 22 and 23 and the direction of the cooling air are perpendicular to each other.
From another point of view, the snubber capacitors 22 and 23 have a flat shape, respectively, and are mounted on the printed wiring board 60 so that the flat surfaces 22z and 23z are parallel to each other. The directions in which the first conductor patterns k1 and h1 and the second conductor patterns k2 and h2 extend are parallel to the flat surfaces 22z and 23z described above.

A plurality of snubber capacitors 22 and 23 are arranged so that the cooling air from the fan F can flow through the gap between the adjacent snubber capacitors 22 and 23. According to such a configuration, a gap through which the cooling air from the fan F flows is provided between the snubber capacitors 22 and 23. As a result, both the snubber capacitors 22 and 23 are appropriately cooled, and their lifetimes are substantially equal.

The matter that the flat surfaces 22z and 23z of the snubber capacitors 22 and 23 and the directions in which the first conductor patterns k1 and h1 and the second conductor patterns k2 and h2 extend are "parallel". Is not limited to "parallel" in the strict sense. That is, the structure may be such that the cooling air from the fan F flows through the gap between the snubber capacitors 22 and 23, and the flat surfaces 22z and 23z of the snubber condenser and the first conductor patterns k1 and h1 and the second conductor pattern If the angle between the extending direction of k2 and h2 is, for example, 15 ° or less, it is included in the above-mentioned "parallel" item.

FIG. 9B is an explanatory view when the conductor pattern on the solder surface of the printed wiring board 60 is seen through from the component surface side.
The second conductor patterns k2 and h2 are wirings that connect the snubber capacitor 21 and the power conversion circuit 30. The terminals 22a and 23a on the positive electrode side of the snubber capacitors 22 and 23 are electrically connected to the second conductor pattern k2. The terminals 22b and 23b on the negative electrode side of the snubber capacitors 22 and 23 are electrically connected to the other second conductor pattern h2.

Then, the first conductor pattern k1 (see FIG. 9A) near the input terminal IP on the positive electrode side of the power conversion circuit 30 and the second conductor pattern k2 (see FIG. 9B) on the positive electrode side form an insulating layer of the printed wiring board 60. They are close to each other with (not shown) in between. Similarly, the first conductor pattern h1 (see FIG. 9A) near the input terminal IN on the negative electrode side of the power conversion circuit 30 and the second conductor pattern h2 (see FIG. 9B) on the negative electrode side are insulated from the printed wiring board 60. They are close to each other with a layer (not shown) in between.

Then, the magnetic flux of the first conductor pattern k1 and the magnetic flux of the second conductor pattern k2 are generated by the currents flowing in opposite directions in the first conductor pattern k1 and the second conductor pattern k2 (see the solid line arrow). Cancel each other. As a result, the counter electromotive force associated with the parasitic inductance is reduced. Since the principle of reducing the back electromotive force is the same as that of the first embodiment, the description thereof will be omitted.

<Effect>
According to the third embodiment, currents in opposite directions flow in the first conductor pattern k1 and the second conductor pattern k2 that are close to each other with the insulating layer (not shown) of the printed wiring board 60 in between. As a result, the counter electromotive force associated with the parasitic inductance is suppressed, and the spike voltage is reduced.

Further, by providing the snubber capacitors 22 and 23 connected in parallel to each other, the overall parasitic inductance of the snubber capacitors 22 and 23 is reduced. Therefore, the effect of reducing the spike voltage is further enhanced as compared with the first embodiment.

Further, the arrangement direction of the snubber capacitors 22 and 23 and the direction in which the second conductor patterns k2 and h2 extend are perpendicular to each other. Therefore, as compared with the first embodiment, the length of the second conductor pattern k2 (see FIG. 9B) on the positive electrode side is longer than that of the first embodiment (see FIG. 4B). As described above, even if the length of the second conductor pattern k2 is relatively long, the parasitic inductance is reduced as a whole, so that the spike voltage is also reduced. As described above, according to the third embodiment, it is possible to increase the degree of freedom when arranging the plurality of snubber capacitors 22 and 23 while reducing the spike voltage.

Further, according to the third embodiment, since the air volumes of the cooling air hitting the snubber capacitors 22 and 23 are substantially equal, the heat generation amounts of both are substantially equal. As a result, the life of the snubber capacitors 22 and 23 becomes substantially the same, so that the labor and cost required for replacing these parts can be reduced.

<< Fourth Embodiment >>
A fourth embodiment describes an air conditioner W (refrigeration cycle device: see FIG. 10) including the power conversion device 100 (see FIG. 10) described in the first embodiment. Since the configuration of the power conversion device 100 is the same as that of the first embodiment, the description thereof will be omitted.

FIG. 10 is a configuration diagram of the air conditioner W according to the fourth embodiment.
The air conditioner W shown in FIG. 10 is, for example, a multi air conditioner for buildings and has a function of performing predetermined air conditioning. In the fourth embodiment, as an example, a case where the air conditioner W mainly performs the cooling operation will be described.
As shown in FIG. 10, the air conditioner W includes a compressor 1, an outdoor heat exchanger 2, an outdoor fan 3, an expansion valve 4, an indoor heat exchanger 5, an indoor fan 6, and a power converter. It has 100 and. Further, the refrigerant circuit Q shown in FIG. 10 has a configuration in which the compressor 1, the outdoor heat exchanger 2, the expansion valve 4, and the indoor heat exchanger 5 are sequentially connected in an annular shape via the pipe q.

The compressor 1 is a device that compresses a gaseous refrigerant, and includes a motor M as a drive source. Although omitted in FIG. 10, an accumulator for gas-liquid separation of the refrigerant is provided on the suction side of the compressor 1.

The power conversion device 100 is a device that performs predetermined power conversion and outputs the power after power conversion to the motor M of the compressor 1, and has the same configuration as that of the first embodiment. That is, the power conversion device 100 converts the DC voltage applied from the DC power supply E into an AC voltage, and applies this AC voltage to the motor M of the compressor 1.

The outdoor heat exchanger 2 is a heat exchanger in which heat exchange is performed between the refrigerant passing through the heat transfer tube (not shown) and the outside air sent from the outdoor fan 3.
The outdoor fan 3 is a fan that sends outside air to the outdoor heat exchanger 2, and is installed in the vicinity of the outdoor heat exchanger 2.

The expansion valve 4 is a valve that reduces the pressure of the refrigerant condensed by the outdoor heat exchanger 2 (condenser). Then, the refrigerant decompressed by the expansion valve 4 is guided to the indoor heat exchanger 5 (evaporator).

The indoor heat exchanger 5 is a heat exchanger in which heat exchange is performed between the refrigerant passing through the heat transfer tube (not shown) and the indoor air (air in the air conditioning target space) sent from the indoor fan 6. Is.
The indoor fan 6 is a fan that sends indoor air to the indoor heat exchanger 5, and is installed in the vicinity of the indoor heat exchanger 5.

In the example shown in FIG. 10, the compressor 1, the outdoor heat exchanger 2, the outdoor fan 3, the expansion valve 4, and the power conversion device 100 are provided in the outdoor unit Wo. On the other hand, the indoor heat exchanger 5 and the indoor fan 6 are provided in the indoor unit Wi.

Then, for example, during the cooling operation, the refrigerating cycle is sequentially performed in the refrigerant circuit Q via the compressor 1, the outdoor heat exchanger 2 (condenser), the expansion valve 4, and the indoor heat exchanger 5 (evaporator). The refrigerant circulates in.

The configuration of the air conditioner W is not limited to the example of FIG. For example, a four-way valve (not shown) for switching the flow path of the refrigerant may be provided in the refrigerant circuit Q. In such a configuration, during the heating operation, the refrigerant circulates in the refrigeration cycle through the compressor 1, the indoor heat exchanger 5 (condenser), the expansion valve 4, and the outdoor heat exchanger 2 (evaporator) in that order. To do.

That is, in the refrigerant circuit Q in which the refrigerant flows sequentially through the compressor 1, the "condenser", the expansion valve 4, and the "evaporator", one of the "condenser" and the "evaporator" exchanges outdoor heat. The vessel 2 and the other is the indoor heat exchanger 5.

<Effect>
According to the fourth embodiment, the air conditioner W includes a power conversion device 100 having the same configuration as that of the first embodiment. As a result, it is possible to provide an air conditioner W having high energy efficiency (APF: Annual Performance Factor) and high reliability.

≪Modification example≫
Although the power conversion device 100, the air conditioner W, and the like according to the present invention have been described above in each embodiment, the present invention is not limited to these descriptions, and various modifications can be made.
For example, in the first embodiment and the third embodiment, the configuration in which the pattern layer is formed on the two layers of the component surface and the solder surface of the printed wiring board 60 has been described, but the pattern layer may be three or more layers. .. That is, the printed wiring board 60 may have a plurality of pattern layers, and an insulating layer may be interposed between the plurality of pattern layers. Then, the first conductor patterns k1 and h1 and the second conductor patterns k2 and h2 may be provided in different pattern layers.

Further, in the third embodiment (see FIG. 8), the configuration in which the two snubber capacitors 22 and 23 are connected in parallel has been described, but the present invention is not limited to this. That is, it may be configured in which three or more snubber capacitors are connected in parallel.

<Semiconductor switching element>
In the power conversion circuit 30 (see FIG. 1) according to the first embodiment, the configuration in which the semiconductor switching elements 31 to 36 are IGBTs has been described, but the present invention is not limited thereto. For example, as semiconductor switching elements 31 to 36, MOSFETs (Metal Oxide Semiconductor Field Effect Transistor), superjunction MOSFETs, BiCMOS (Bipolar: CMOS), thyristors (Silicon Controlled Rectifier), GTO (Gate Turn-Off Thyrisor) and the like are used. You may.

<Power conversion circuit>
In each embodiment, the configuration in which the power conversion circuit 30 (see FIG. 1) is a three-phase inverter circuit that converts a DC voltage into a three-phase AC voltage has been described, but the present invention is not limited to this. For example, each embodiment can be applied even when a single-phase inverter circuit (power conversion circuit) that converts a DC voltage into a single-phase AC voltage is used. Further, each embodiment can also be applied when a DC-DC converter circuit (power conversion circuit) that converts a DC voltage into a DC voltage having a different magnitude is used. In addition, each embodiment can be applied to an active filter (a device that suppresses a harmonic current leaking from an inverter device or the like to an AC power source side) provided with a predetermined inverter circuit.

<DC power supply>
In the first embodiment, the specific configuration of the DC power supply E (see FIG. 1) has not been described, but in addition to the solar cell and the battery, a DC power supply obtained by rectifying and smoothing the AC voltage is used. May be done.

In the third embodiment (see FIG. 9A), the configuration in which the snubber capacitors 22 and 23 are arranged so that the flat surfaces 22z and 23z are parallel has been described, but the flat surfaces 22z and 23z do not have to be parallel. .. Even with such a configuration, the effect of reducing power loss and electromagnetic noise can be achieved. Further, the snubber capacitors 22 and 23 may have a shape different from the flat rectangular shape (see FIG. 9A) in a plan view.

<Refrigeration cycle equipment>
In the fourth embodiment, the air conditioner W (see FIG. 10) in which one outdoor unit Wo and one indoor unit Wi are provided has been described, but the present invention is not limited to this. For example, in one system of air conditioners, each embodiment can be applied to a multi-type air conditioner provided with a plurality of indoor units.

Further, in the fourth embodiment, the air conditioner W (refrigeration cycle device: see FIG. 10) including the power conversion device 100 has been described, but the present invention is not limited to this. For example, the fourth embodiment can be applied to other "refrigeration cycle devices" such as refrigerators, water heaters, and air-conditioned water heaters.

In addition, each embodiment can be combined as appropriate. For example, in a configuration (third embodiment) in which the second embodiment (see FIGS. 7A and 7B) and the third embodiment (see FIG. 8) are combined and the snubber capacitors 22 and 23 are connected in parallel, the printed wiring board The configuration may be such that the conductor pattern is mounted on one side of the 60 (second embodiment). In addition, for example, the second embodiment and the fourth embodiment may be combined, or the third embodiment and the fourth embodiment may be combined.

Further, each embodiment is described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the configurations described. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.
In addition, the above-mentioned mechanism and configuration show what is considered necessary for explanation, and do not necessarily show all the mechanisms and configurations in the product.

1 Compressor 2 Outdoor heat exchanger (condenser / evaporator)
3 Outdoor fan 4 Expansion valve 5 Indoor heat exchanger (evaporator / condenser)
6 Indoor fan 10 Smoothing capacitor 20, 20A, 20B Parasitic inductance reducing means 21, 22, 23 Snubber capacitor 22z, 23z Flat surface 30 Power conversion circuit 31, 32, 33, 34, 35, 36 Semiconductor switching element 50 Control means 60, 60A Printed circuit board 60s Insulation layer 70 Inductor 100, 100B Power converter E DC power supply F fan Ga, Gb Screw Ha, Hb Screw hole IP input terminal (input terminal on the positive side)
IN input terminal (input terminal on the negative electrode side)
Lp parasitic inductance M motor N Negative electrode side power supply line (DC power supply line)
P Positive electrode side power supply line (DC power supply line)
Q Refrigerant circuit W Air conditioner (refrigeration cycle device)
k1 1st conductor pattern (1st conductor pattern on the positive electrode side)
h1 1st conductor pattern (1st conductor pattern on the negative electrode side)
k2 2nd conductor pattern (2nd conductor pattern on the positive electrode side)
h2 2nd conductor pattern (2nd conductor pattern on the negative electrode side)

Claims (8)

Printed wiring board and
A power conversion circuit mounted on the printed wiring board and to which a DC voltage is applied from a DC power supply via a DC power supply line.
A snubber capacitor mounted on the printed wiring board and connected to the input side of the power conversion circuit is provided.
The printed wiring board
A first conductor pattern that is connected to each of the positive electrode side and the negative electrode side of the power conversion circuit and forms a part of the DC power supply line.
It has a second conductor pattern that connects the power conversion circuit and the snubber capacitor on the positive electrode side and the negative electrode side, respectively.
The second conductor pattern on the positive electrode side is provided in the vicinity of the input terminal on the positive electrode side of the power conversion circuit so as to be close to the first conductor pattern on the positive electrode side.
A power conversion device in which the second conductor pattern on the negative electrode side is provided near the input terminal on the negative electrode side of the power conversion circuit so as to be close to the first conductor pattern on the negative electrode side. Further equipped with a radiator fixed to the power conversion circuit using screws,
The power conversion circuit is arranged between the printed wiring board and the radiator.
The power conversion device according to claim 1, wherein a screw hole is provided at a position corresponding to the screw in the printed wiring board, and the snubber capacitor is mounted at a position away from the screw hole. The printed wiring board has a plurality of pattern layers and has a plurality of pattern layers.
An insulating layer is interposed between the plurality of pattern layers,
The power conversion device according to claim 1, wherein the first conductor pattern and the second conductor pattern are provided in the pattern layers that are different from each other. The printed wiring board has one pattern layer and has one pattern layer.
The power conversion device according to claim 1, wherein the first conductor pattern and the second conductor pattern are provided side by side in one of the pattern layers. A plurality of the snubber capacitors connected in parallel are mounted on the printed wiring board.
Any of claims 1 to 4, wherein the power conversion circuit and the plurality of snubber capacitors are connected to each of the positive electrode side and the negative electrode side via the second conductor pattern. The power conversion device according to one item. Further equipped with a fan for sending cooling air to the printed wiring board,
The power conversion device according to claim 5, wherein a plurality of the snubber capacitors are arranged so that cooling air from the fan can flow through a gap between adjacent snubber capacitors. .. Each of the plurality of snubber capacitors has a flat shape, and is mounted on the printed wiring board so that the flat surfaces are parallel to each other.
The power conversion device according to claim 6, wherein the direction in which the first conductor pattern and the second conductor pattern extend is parallel to the flat surface. A refrigerant circuit in which the refrigerant circulates in sequence through the compressor, condenser, expansion valve, and evaporator.
Includes a power conversion device that performs predetermined power conversion and outputs the power after power conversion to the motor of the compressor.
The power converter
Printed wiring board and
A power conversion circuit mounted on the printed wiring board and to which a DC voltage is applied from a DC power supply via a DC power supply line.
A snubber capacitor mounted on the printed wiring board and connected to the input side of the power conversion circuit is provided.
The printed wiring board
A first conductor pattern that is connected to each of the positive electrode side and the negative electrode side of the power conversion circuit and forms a part of the DC power supply line.
It has a second conductor pattern that connects the power conversion circuit and the snubber capacitor on the positive electrode side and the negative electrode side, respectively.
The second conductor pattern on the positive electrode side is provided in the vicinity of the input terminal on the positive electrode side of the power conversion circuit so as to be close to the first conductor pattern on the positive electrode side.
A refrigeration cycle apparatus in which the second conductor pattern on the negative electrode side is provided in the vicinity of the input terminal on the negative electrode side of the power conversion circuit so as to be close to the first conductor pattern on the negative electrode side.

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