Power conversion device

Abstract

To provide a power conversion device capable of suppressing sound generated from a fan without increasing the number of components and including a cover capable of suppressing intrusion of dust or the like.SOLUTION: The outdoor installation type power conversion device 100 includes a housing 10 that accommodates a power conversion unit 20 that converts AC power and DC power, a fan 51 that is disposed inside the housing 10 and cools the power conversion unit 20, and a fan cover 52 that covers an intake port 10a through which intake or discharge is performed, the fan 51 is configured to perform intake or discharge via an opening 52b provided below the fan cover 52, and the fan cover 52 includes a hood portion 52a and a first recessed portion forming plate 52a provided inside the hood portion 52c. The first recessed part forming plate 52c and the inner surface of the hood part 52a constitute a sound suppressing recessed part 52e for radiating reflected sound s1 for suppressing radiated sound s2 generated from the fan 51.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a power conversion device, and more particularly to a power conversion device that cools a power conversion unit in a housing by a fan. [Background technology]

[0002] BACKGROUND ART Conventionally, an air supply system that cools the inside of a housing by a fan is known (see, for example, Patent Document 1).

[0003] The air supply system of Patent Document 1 includes an axial fan as a sound source installed inside the housing, and a silencer on the intake side of the axial fan for silencing noise generated by the axial fan. The air supply system of Patent Document 1 also includes an axial fan and a silencer arranged so that the openings of the silencer are aligned in a straight line and connected to the outside. The silencer of Patent Document 1 includes an L-shaped resonance silencer inside the opening. The silencer of Patent Document 1 radiates reflected sound generated by the axial fan and reflected by the resonance silencer so that the radiated sound generated by the axial fan has an opposite phase to the radiated sound. As a result, in the air supply system disclosed in Patent Document 1, the radiated sound from the axial fan and the radiated sound from the resonance silencer cancel each other out, suppressing the radiated sound of the axial fan. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 171710 Summary of the Invention [Problem to be solved by the invention]

[0005] However, as in Patent Document 1, the openings of the axial fan and the silencer are arranged in a straight line and connected to the outside, which can cause the axial fan to suck in dust and other particles in the air. In this case, the axial fan and the object to be cooled placed inside the housing can be damaged (broken down) due to the sucked in dust and other particles. However, providing a cover or other component separate from the silencer to prevent the intrusion of dust and other particles in the air increases the number of components, which can lead to a complex structure. Therefore, there is a need for a power conversion device that can suppress the noise generated by the fan without increasing the number of components and that includes a cover that can prevent the intrusion of dust and other particles.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a power conversion device that is equipped with a cover that can suppress the noise generated by the fan without increasing the number of components and can prevent the intrusion of dust and the like. [Means for solving the problem]

[0007] A power conversion device according to one aspect of the present invention comprises a housing that houses a power conversion unit that converts AC power and DC power, a fan arranged inside the housing to cool the power conversion unit, and a fan cover that covers an intake and exhaust unit where air is taken in or exhausted by the fan, the fan being configured to take in or exhaust air through an opening provided below the fan cover, the fan cover including a cover body and a first partition plate provided inside the cover body, and the first partition plate and the inner surface of the cover body form a sound suppression recess that radiates reflected sound to suppress radiated sound generated from the fan.

[0008] As described above, a power conversion device according to one aspect of the present invention includes a fan that cools the power conversion unit and a fan cover that covers an intake / exhaust unit of the fan that takes in or exhausts air. As a result, the fan cover covers the intake / exhaust unit of the fan, thereby preventing dust and other particles floating in the air from entering the fan. Also, in the power conversion device according to one aspect of the present invention, as described above, the fan cover includes a cover main body and a first partition plate provided inside the cover main body. The first partition plate and the inner surface of the cover main body form a sound-suppressing recess that emits reflected sound to suppress radiated sound generated from the fan. As a result, the sound-suppressing recess formed inside the fan cover emits reflected sound that suppresses radiated sound generated from the fan, thereby suppressing sound generated from the fan inside the fan cover. In other words, a single fan cover can suppress both the sound generated from the fan and the intrusion of dust and other particles. As a result, a power conversion device can be provided that includes a cover that can suppress sound generated from the fan and prevent the intrusion of dust and other particles without increasing the number of components.

[0009] In the power converter according to the above aspect, the power converter is preferably placed outdoors, and the cover body of the fan cover forms a rain hood that protects the fan from rain, and the rain hood has a noise-suppressing recess formed inside. With this configuration, because the fan cover forms the rain hood for the power converter, it is possible to prevent the fan from suctioning raindrops and the like even when the power converter is placed outdoors.

[0010] In the power converter according to the above aspect, the sound-suppressing recess is preferably arranged inside the fan cover so as to radiate reflected sound from a position closer to the intake and exhaust section of the fan than the opening of the fan cover. With this configuration, the radiated sound generated from the fan can be prevented from traveling near the opening of the fan cover, and is therefore muted near the intake and exhaust section. As a result, the radiated sound generated from the fan can be effectively prevented from leaking outside the fan cover.

[0011] In the power converter according to the above aspect, the fan cover preferably includes a second partition plate that guides radiated sound generated from the fan toward the sound-suppressing recessed portion. With this configuration, the radiated sound generated from the fan is guided by the second partition plate toward the sound-suppressing recessed portion that generates reflected sound, thereby preventing the sound generated by the fan from leaking to the outside and enabling efficient noise reduction.

[0012] In this case, the sound-suppressing recess is preferably configured to generate reflected sound so that the radiated sound and the reflected sound interfere with each other near the end of the second partition plate on the sound-suppressing recess side. With this configuration, the radiated sound from the fan traveling along the second partition plate is muted near the end of the second partition plate, so that the radiated sound from the fan can be muted before it leaks out to the outside from a position where there is no second partition plate.

[0013] In this case, the fan cover is preferably provided to connect the intake and exhaust section and the opening, includes a ventilation passage through which air taken in or exhausted by the fan passes, and includes a third partition plate that protrudes into the ventilation passage and is positioned to block the progression of radiated sound. With this configuration, radiated sound generated by the fan and traveling through the ventilation passage is reflected off the third partition plate and attenuated, so that even if it leaks out, it can be emitted at a low volume.

[0014] In the power conversion device in which the fan cover constitutes the rain hood, the fan cover is preferably provided to connect the intake and exhaust section to the opening, and includes a ventilation channel through which air taken in or exhausted by the fan passes, and the sound suppression recess is configured to extend in the vertical direction along the ventilation channel. With this configuration, the sound suppression recess is formed along the vertically extending ventilation channel, so that the horizontal size of the fan cover can be made smaller than, for example, when the sound suppression recess is formed in the horizontal direction perpendicular to the vertically extending ventilation channel.

[0015] In the power converter in which the fan cover constitutes a rain hood, the width of the sound-suppressing recess, as viewed from a second direction perpendicular to both the first direction in which the fan and fan cover are aligned and the up-down direction, is preferably closer to the opening width of the intake and exhaust section as viewed from the second direction than to the opening width of the opening as viewed from the second direction. With this configuration, the width of the sound-suppressing recess, as viewed from the second direction, is closer to the opening width of the intake and exhaust section that radiates radiated sound than to the opening width of the fan cover, so the sound-suppressing recess can radiate reflected sound that can appropriately muffle radiated sound radiated from the intake and exhaust section. As a result, radiated sound generated by the fan can be effectively muffled.

[0016] In the power converter in which the fan cover constitutes a rain hood, the first partition plate is preferably configured so that the length of the portion of the first partition plate that constitutes the sound-suppressing recess can be changed. With this configuration, the length of the sound-suppressing recess can be changed by changing the length of the portion of the first partition plate that constitutes the sound-suppressing recess. As a result, the length of the sound-suppressing recess can be changed appropriately depending on the wavelength of the radiated sound.

[0017] In the power converter in which the fan cover constitutes the rain hood, preferably, a plurality of fans are provided, and a fan cover is provided corresponding to each of the plurality of fans. With this configuration, it is possible to provide a fan cover with a sound-suppressing recess of an appropriate size according to the frequency of the radiated sound generated by each of the plurality of fans. As a result, even when a plurality of fans are provided, the sound generated by the fans can be effectively suppressed. [Effects of the Invention]

[0018] According to the present invention, as described above, it is possible to provide a power conversion device that is capable of suppressing the noise generated by the fan without increasing the number of components and that is equipped with a cover that can prevent the intrusion of dust and the like. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram showing a configuration of an outdoor-installed power conversion device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of an air supply unit according to the first embodiment of the present invention. [Figure 3] 3A to 3C are diagrams illustrating the principle of noise reduction by the fan cover according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a diagram for explaining the simulation results of the noise reduction effect of the fan cover according to the first embodiment of the present invention. [Figure 5] FIG. 4 is a diagram for explaining the results of measurements of the noise reduction effect of the fan cover according to the first embodiment of the present invention. [Figure 6] FIG. 10 is a cross-sectional view showing the configuration of an air supply unit according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a cross-sectional view showing the configuration of the air supply unit according to a first modified example of the first embodiment of the present invention. [Figure 8] FIG. 10 is a cross-sectional view showing the configuration of the air supply unit according to a second modified example of the first embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings.

[0021] [First embodiment] First, with reference to FIG. 1, the configuration of an outdoor power conversion device 100 according to a first embodiment will be described.

[0022] (Configuration of outdoor power conversion device) As shown in Fig. 1, the outdoor-installed power conversion apparatus 100 includes a housing 10, a power conversion unit 20, a reactor 30, a control device 40, and an air supply unit 50. The outdoor-installed power conversion apparatus 100 is an apparatus that is installed outdoors and stores power generated by natural energy such as sunlight, and supplies the power to other electrical appliances. The outdoor-installed power conversion apparatus 100 is an example of a "power conversion apparatus" in the claims.

[0023] In the following description, the left-right direction (one direction in a horizontal plane) when viewing the outdoor-installed power conversion apparatus 100 from the side is defined as the Y direction, with one side of the Y direction being the Y1 direction and the other side being the Y2 direction. The up-down direction (vertical direction) of the outdoor-installed power conversion apparatus 100 is defined as the Z direction, with the upward direction being the Z1 direction and the downward direction being the Z2 direction. The direction orthogonal to the Y direction and Z direction of the outdoor-installed power conversion apparatus 100 (the other direction in a horizontal plane) is defined as the X direction, with the front side of the outdoor-installed power conversion apparatus 100 being the X1 direction and the rear side being the X2 direction. That is, the air supply unit 50 is provided on the rear side of the outdoor-installed power conversion apparatus 100. The X direction is an example of a "second direction" in the claims, and the Y direction is an example of a "first direction" in the claims.

[0024] The housing 10 includes a first cooling space 11, a second cooling space 12, an airtight space 13, and a ventilation space 14, and is fixed to a base 15. The housing 10 has an air intake port 10a through which air 200 passes, on the Y1-direction surface on which the air supply unit 50 is attached. The first cooling space 11 is a space in which the power conversion unit 20 is disposed, and through which the air 200 from the air supply unit 50 passes. The second cooling space 12 is a space in which the reactor 30 is disposed, and through which the air 200 from the air supply unit 50 passes. The airtight space 13 is sealed with the control device 40 disposed therein, and is a partitioned space so that the air 200 from the air supply unit 50 does not pass through. The ventilation space 14 is a space through which the air 200 discharged from the first cooling space 11 and the second cooling space 12 passes to be exhausted to the outside of the housing 10. The base 15 is made of concrete or the like on the ground, and is a platform on which the housing 10 is stably placed.

[0025] The power conversion unit 20 performs power conversion processing and stores DC power. In the first embodiment, the power conversion unit 20 includes, for example, a PCS (Power Conditioning System) 21 and a power storage device 22. The PCS 21 converts DC power output from the power storage device 22 into AC power and outputs the converted AC power to a power grid facility (not shown). The PCS 21 includes a power conversion circuit having a plurality of switching elements (not shown) and converts AC power supplied from the power grid facility (not shown) into DC power. The power storage device 22 includes a secondary battery that charges DC power, such as a lithium-ion secondary battery. The PCS 21 charges the power storage device 22 with AC power from the power grid facility (not shown) or DC power supplied from a power generation unit (not shown) that uses natural energy. The power conversion unit 20 is cooled by three air supply units 50 arranged in the first cooling space 11.

[0026] The reactor 30 is one of the elements constituting a power conversion circuit (not shown) included in the PCS 21 of the power conversion unit 20. The reactor 30 generates a relatively large amount of heat and is heavy, so it is separated from the power conversion unit 20 and placed in a second cooling space 12 provided below the first cooling space 11 in which the power conversion unit 20 is placed. The reactor 30 is cooled by two air supply units 50 placed in the second cooling space 12.

[0027] The control device 40 includes, for example, a central processing unit (CPU) as a processor, a read-only memory (ROM), a random access memory (RAM), and the like, and controls the operation of the power conversion unit 20 by executing a program (software). The control device 40 includes a control board (not shown) on which a plurality of circuit elements are arranged. The circuit elements included in the control device 40 are susceptible to damage due to the influence of dust in the atmosphere, and therefore, unlike the power conversion unit 20 and the reactor 30, are arranged in an airtight space 13 where no air flows.

[0028] (Structure of the air supply unit) Next, the configuration of the air supply unit 50 will be described with reference to FIG. 2. FIG. 2 is an enlarged cross-sectional view of one air supply unit 50 provided in the housing 10 of the outdoor-installed power conversion device 100 of FIG. 1. As shown in FIG. 2, the air supply unit 50 is composed of a fan 51, a fan cover 52, and a water draining portion 53. Of the air supply unit 50, the fan 51 and the water draining portion 53 are provided inside the housing 10, and the fan cover 52 is arranged outside the housing 10 on the Y1 direction side. Note that in this first embodiment, a fan cover 52 is provided corresponding to each of the multiple fans 51. Furthermore, the water draining portion 53 is provided in common to the multiple fans 51. Specifically, one water draining portion 53 is provided in common to the three fans 51 that supply air to the first cooling space 11, and one water draining portion 53 is provided in common to the two fans 51 that supply air to the second cooling space 12.

[0029] The fan 51 is composed of rotating blades 51a and a casing 51b, and is fixed to the inner wall of the housing 10 using fasteners (not shown). The rotating blades 51a are controlled by the control device 40, for example, to rotate at high speed, thereby generating cooling air that cools the power conversion unit 20 and the reactor 30. That is, in this first embodiment, the fan 51 draws in outside air 200 and sends it into the housing 10. The casing 51b has openings (not shown) through which screws or the like for attaching the fan 51 are inserted, and is fixed to the drainage section 53 by the screws or the like. The fan 51 draws in outside air 200 through an air intake 10a opened in the inner wall of the housing 10 and sends the air 200 into the housing 10 through an air outlet 51c. The air intake 10a is an example of an "intake and exhaust section" in the claims.

[0030] The fan cover 52 includes a hood portion 52a, an opening 52b, a recessed portion forming plate 52c, a bottom portion 52d, a sound suppression recess 52e, a sound guide plate 52f, a sound suppression plate 52g, and a ventilation passage 52h. The fan cover 52 is made of a metal with relatively high corrosion resistance, such as aluminum. The fan cover 52 is fixed to the outer wall of the housing 10 by fastening members or the like via a packing (sealing member) or the like (not shown), and functions as a rain hood that prevents raindrops and the like from entering the fan 51 through the air intake port 10a. The recessed portion forming plate 52c is an example of a "first partition plate" in the claims, the sound guide plate 52f is an example of a "second partition plate" in the claims, and the sound suppression plate 52g is an example of a "third partition plate" in the claims.

[0031] The hood portion 52a is formed to cover the intake port 10a in the Z1, X, and Y directions. The hood portion 52a has an inclined surface in the Z1 direction to prevent raindrops from accumulating. The hood portion 52a is formed to have a rectangular shape when viewed from the Z direction, for example. The hood portion 52a is an example of the "cover body" and "rain hood portion" in the claims.

[0032] The opening 52b is an opening portion located in the Z2 direction of the hood portion 52a. Air 200 drawn in by the fan 51 passes through the opening 52b. The opening 52b has an opening width of w1 in the Y direction.

[0033] The recess-forming plate 52c is formed integrally with the hood portion 52a inside the hood portion 52a and is a plate-like member extending in the Z direction along the ventilation passages 52h (described later). The recess-forming plate 52c is connected to the bottom portion 52d in the Z2 direction. The space enclosed by the hood portion 52a, the recess-forming plate 52c, and the bottom portion 52d constitutes the sound-suppressing recess 52e. That is, the sound-suppressing recess 52e is a recessed portion inside the hood portion 52a that is not connected to the outside. The width w2 of the sound-suppressing recess 52e as viewed from the X direction is closer to the height (width) h1, which is the opening width of the air intake port 10a as viewed from the Y direction, than the opening width w1 of the opening 52b of the fan cover 52 as viewed from the Y direction. In this first embodiment, the width w2 of the sound-suppressing recess 52e in the Y direction is formed to be equal to the height (width) h1 of the air intake port 10a, for example.

[0034] Sound guide plate 52f is a plate that protrudes in the Y direction inside hood portion 52a and is formed integrally with hood portion 52a. Sound guide plate 52f is disposed inclined from the vicinity of air intake port 10a at the same inclination angle as the Z1-direction surface of hood portion 52a, and is configured to guide radiated sound s1 toward sound suppression recess 52e.

[0035] The sound suppression plate 52g is inclined at an angle different from the Z1-direction surface of the hood portion 52a and is formed integrally with the hood portion 52a so as to suppress the propagation of the radiated sound s1 to the outside. Specifically, the sound suppression plate 52g is arranged so as to incline in the Z2 direction as it extends from the Y1 direction toward the Y2 direction. As a result, an S-shaped ventilation passage 52h is formed inside the hood portion 52a, connecting the air intake 10a and the opening 52b of the fan cover 52. The air 200 drawn in by the fan 51 flows along this ventilation passage 52h.

[0036] (Noise reduction method using a fan cover) Next, a method for suppressing noise generated from the fan 51 using the fan cover 52 will be described with reference to FIG. 3. As shown in FIG. 3, the rotating blades 51a of the fan 51 rotate at high speed to generate cooling air, and thus radiated sound s1 is emitted from the rotating blades 51a as wind noise. This radiated sound s1 generates a loud sound (peak sound) at a specific frequency depending on the number of blades in the rotating blades 51a and the rotation speed of the rotating blades 51a. Specifically, the radiated sound s1 generated from the fan 51 generates a peak sound at a frequency expressed by the formula rotation speed [rpm] × number of blades / 60 × n [Hz] (n is a natural number). Therefore, the wavelength of the radiated sound s1 is the reciprocal of the frequency at which the peak sound is generated.

[0037] The radiated sound s1 travels along the inner wall of the hood portion 52a and enters the sound suppression recess 52e, where it is reflected by the bottom portion 52d. This generates reflected sound s2. The reflected sound s2 travels along the inner wall of the hood portion 52a and travels from the upper portion (Z1 direction) of the recess forming plate 52c toward the direction in which the fan 51 is disposed. In this first embodiment, the opening of the sound suppression recess 52e is located inside the hood portion 52a closer to the air intake 10a than the opening 52b of the fan cover 52. Therefore, the sound suppression recess 52e radiates reflected sound s2 from a position inside the fan cover 52 that is closer to the air intake 10a than the opening 52b of the fan cover 52.

[0038] Furthermore, the sound suppression recess 52e generates a reflected sound s2 such that the radiated sound s1 and the reflected sound s2 interfere with each other at position P near the end of the sound guide plate 52f on the sound suppression recess 52e side. That is, the phase of the reflected sound s2 at position P is opposite to the phase of the radiated sound s1 at position P, and the reflected sound s2 interferes with the radiated sound s1. The sound suppression recess 52e is designed so that the amplitude of the wavelengths of the radiated sound s1 and the reflected sound s2 is maximized at position P. As a result, the radiated sound s1 and the reflected sound s2 interfere with each other at position P, generating standing waves that weaken the sounds, thereby silencing the radiated sound s1 generated from the fan 51. Furthermore, because position P is near the center of the ventilation passage 52h in the Y direction, the radiated sound s1 is silencing near the center of the ventilation passage 52h in the Y direction.

[0039] In the first embodiment, the fan cover 52 has a structure that muffles the lowest frequency peak sound among the peak sounds generated by the fan 51. That is, the length in the Z direction of the recess forming plate 52c is designed according to the wavelength of the lowest frequency peak sound so that the lowest frequency peak sound is muffled at position P.

[0040] Here, position P is the center position between air intake port 10a and recess-forming plate 52c, and distance d1 from air intake port 10a to position P and distance d2 from recess-forming plate 52c to position P are equal. That is, at position P, the radiated sound s1 and the reflected sound s2 are out of phase, meaning that the phase of radiated sound s1 at air intake port 10a is out of phase with the phase of reflected sound s2 at the upper part of recess-forming plate 52c. Therefore, the length of sound suppression recess 52e is designed so that the phase of reflected sound s2 at the upper part of recess-forming plate 52c is inverse to the phase of radiated sound s1 at air intake port 10a. In this first embodiment, the length of recess-forming plate 52c in the Z direction (the length of sound suppression recess 52e) is designed to be, for example, about ¼ the wavelength of the lowest frequency peak sound.

[0041] Water draining section 53 forms flow path 53b with main body 53a. Water draining section 53 is provided to allow raindrops and the like that cannot be prevented from entering housing 10 by fan cover 52 to flow into flow path 53b and prevent them from coming into contact with fan 51. In addition, water draining section 53 has fan 51 attached to main body 53a.

[0042] (Noise reduction effect of fan cover) Next, the effect of the fan cover 52 according to the first embodiment in silencing the radiated sound s1 radiated from the fan 51 will be described with reference to FIGS.

[0043] Figure 4 shows the results of a simulation showing the sound pressure distribution of sound generated from the fan 51 by the fan cover 52. The black areas indicate areas where structures are installed and are not part of the simulation domain. The sound is a sine wave with a predetermined phase that causes positive or negative pressure fluctuations in the surrounding air. In this simulation, the sound from the fan 51 radiated from the intake port 10a through the flow path 53b of the drainage section 53 is radiated as radiated sound s1 with a positive phase. It can be seen that the reflected sound s2 reflected by the bottom 52d of the sound-suppressing recess 52e has a negative phase, which cancels out near position P, resulting in a low sound pressure. This confirms that the sound generated by the fan 51 is silenced by the fan cover 52 as it exits through the opening 52b.

[0044] FIG. 5 shows the results of measurements of ambient noise taken at a position 50 cm away in the Y1 direction from the rear of the outdoor-installed power conversion apparatus 100 (see FIG. 1). The vertical axis of the graph in FIG. 5 represents the difference in sound pressure, expressed as loss [dB], between when the fan 51 is not covered with the fan cover 52 and when the fan 51 is covered with the fan cover 52. In other words, the greater the loss [dB], the more the radiated sound s1 emitted from the fan 51 is suppressed. FIG. 5 shows the results of measurements taken under different Z-direction lengths of the recessed plate 52c (the length of the sound-suppressing recess 52e) under the first and second conditions. Specifically, the Z-direction length of the recessed plate 52c under the first condition (the length of the sound-suppressing recess 52e) is greater than the Z-direction length of the recessed plate 52c under the second condition (the length of the sound-suppressing recess 52e). It can be seen that the noise reduction effect at frequency f1 is very large under the first condition. In addition, the second condition provides a higher sound-damping effect on the short wavelength side, i.e., at frequency f2, which is higher than frequency f1, because the Z-direction length of the recess-forming plate 52c (the length of the sound-suppressing recess 52e) is shorter than that of the first condition.

[0045] (Effects of the first embodiment) Next, the effects of the first embodiment will be described.

[0046] The outdoor-installed power conversion device 100 of the first embodiment includes a housing 10 that houses a power conversion unit 20 that converts AC power and DC power, a fan 51 disposed inside the housing 10 and cooling the power conversion unit 20, and a fan cover 52 that covers an air intake port 10a through which air is taken in or exhausted by the fan 51. The fan 51 is configured to take in or exhaust air through an opening 52b provided below the fan cover 52. The fan cover 52 includes a hood portion 52a and a recess-forming plate 52c provided inside the hood portion 52a. The recess-forming plate 52c and the inner surface of the hood portion 52a form a sound-suppressing recess 52e that radiates reflected sound s2 that suppresses radiated sound s1 generated from the fan 51. By providing the fan cover 52 that covers the air intake port 10a through which air is taken in or exhausted, dust floating in the air can be prevented from entering the fan 51 because the fan cover 52 covers the air intake port 10a. Furthermore, the fan cover 52 includes a hood portion 52a and a recess-forming plate 52c provided inside the hood portion 52a, and the recess-forming plate 52c and the inner surface of the hood portion 52a form a sound-suppressing recess 52e that emits reflected sound s2 that suppresses radiated sound s1 generated from the fan 51. As a result, the sound-suppressing recess 52e formed inside the fan cover 52 emits reflected sound s2 that suppresses radiated sound s1 generated from the fan 51, thereby suppressing the sound generated from the fan 51 inside the fan cover 52. In other words, the single fan cover 52 can suppress the radiated sound s1 generated from the fan 51 and prevent dust and the like from entering. As a result, it is possible to provide an outdoor-installed power conversion device 100 that includes a fan cover 52 that can suppress radiated sound s1 generated from the fan 51 and prevent dust and the like from entering, without increasing the number of components.

[0047] In the first embodiment, the outdoor-installed power conversion apparatus 100 is placed outdoors, and the hood portion 52a of the fan cover 52 forms a rain hood portion 52a that protects the fan 51 from rain, and a noise-suppressing recess 52e is formed inside the rain hood portion 52a. As a result, the fan cover 52 forms a rain hood for the outdoor-installed power conversion apparatus 100, and therefore, even when the outdoor-installed power conversion apparatus 100 is installed outdoors, the fan 51 can be prevented from absorbing raindrops and the like.

[0048] Furthermore, in the first embodiment, sound suppression recess 52e is arranged inside fan cover 52 so as to radiate reflected sound s2 from a position closer to intake port 10a than opening 52b of fan cover 52. This makes it difficult for radiated sound s1 generated from fan 51 to travel to the vicinity of opening 52b of fan cover 52, and therefore the radiated sound s1 is silenced near intake port 10a. As a result, radiated sound s1 generated from fan 51 can be effectively prevented from leaking outside fan cover 52.

[0049] Furthermore, in the first embodiment, the fan cover 52 includes a sound guide plate 52f that guides the radiated sound s1 generated from the fan 51 toward the sound suppression recess 52e. As a result, the radiated sound s1 generated from the fan 51 is guided by the sound guide plate 52f toward the sound suppression recess 52e that generates the reflected sound s2, thereby preventing the radiated sound s1 generated from the fan 51 from leaking to the outside and enabling efficient sound reduction.

[0050] Furthermore, in the first embodiment, the sound suppression recess 52e is configured to generate reflected sound s2 so that radiated sound s1 and reflected sound s2 interfere with each other at position P near the end of the sound guide plate 52f on the sound suppression recess 52e side. As a result, radiated sound s1 from the fan 51 traveling along the sound guide plate 52f is muffled near the end of the sound guide plate 52f, so that radiated sound s1 from the fan 51 can be muffled before it leaks out from a position where there is no sound guide plate 52f.

[0051] Furthermore, in the first embodiment, fan cover 52 is provided to connect intake port 10a and opening 52b, includes ventilation passage 52h through which air 200 taken in or exhausted by fan 51 passes, and includes sound suppression plate 52g that is provided to protrude into ventilation passage 52h and arranged to block the progress of radiated sound s1. As a result, radiated sound s1 generated from fan 51 and traveling through ventilation passage 52h is reflected by sound suppression plate 52g and attenuated, so that even if it leaks out to the outside, it can be output as a low-noise sound.

[0052] Furthermore, in the first embodiment, fan cover 52 is provided to connect air intake 10a and opening 52b, and includes ventilation passage 52h through which air 200 taken in or exhausted by fan 51 passes, and sound suppression recess 52e is configured to extend in the Z direction along ventilation passage 52h. As a result, sound suppression recess 52e is formed along ventilation passage 52h that extends vertically, and therefore the size of fan cover 52 in the Y direction can be made smaller than, for example, when sound suppression recess 52e is formed in the Y direction that is perpendicular to ventilation passage 52h that extends vertically.

[0053] Furthermore, in the first embodiment, sound suppression recess 52e is configured to have a width w2 that is closer to the opening width h1 of intake port 10a than to the opening width w1 of opening 52b. As a result, width w2 of sound suppression recess 52e as viewed from the second direction is closer to the opening width h1 of intake port 10a that radiates radiated sound s1 than to the width w1 of opening 52b of fan cover 52, so sound suppression recess 52e can radiate reflected sound s2 that can appropriately muffle radiated sound s1 radiated from intake port 10a. As a result, radiated sound s1 generated by fan 51 can be effectively muffled.

[0054] Furthermore, in the first embodiment, a plurality of fans 51 are provided, and a fan cover 52 is provided corresponding to each of the plurality of fans 51. This makes it possible to provide each fan cover 52 with a sound suppression recess 52e of an appropriate size according to the frequency of the radiated sound s1 generated by each of the plurality of fans 51. As a result, even when a plurality of fans 51 are provided, the sound generated from the fans 51 can be effectively suppressed.

[0055] [Second embodiment] Next, the configuration of an outdoor-installed power conversion apparatus 101 according to a second embodiment of the present invention will be described with reference to Fig. 1 and Fig. 6. The configuration of the outdoor-installed power conversion apparatus 101 shown in Fig. 1 is the same as that of the outdoor-installed power conversion apparatus 100 shown in the first embodiment, except for the air supply unit 150. Note that in the second embodiment, a description of the points common to the first embodiment will be omitted.

[0056] (Structure of the air supply unit) The air supply unit 150 in the second embodiment will be described with reference to Fig. 6. Fig. 6 is an enlarged cross-sectional view of one air supply unit 150 provided in the housing 10 of the outdoor-installed power conversion device 101 of Fig. 1. As shown in Fig. 6, the air supply unit 150 is composed of a fan 51 and a fan cover 152. Of the air supply unit 150, the fan 51 has the same configuration as in the first embodiment. The fan cover 152 is disposed outside the housing 10 on the Y1 direction side.

[0057] The fan cover 152 includes a hood portion 152a, an opening 152b, a recess-forming plate 152c, a bottom portion 152d, a sound suppression recess 152e, a sound guide plate 152f, a sound suppression plate 152g, and an air passage 152h. Note that the hood portion 152a, the opening 152b, the bottom portion 152d, the sound guide plate 152f, the sound suppression plate 152g, and the air passage 152h each have the same configuration as the hood portion 52a, the opening 52b, the bottom portion 52d, the sound guide plate 52f, the sound suppression plate 52g, and the air passage 52h in the first embodiment, respectively.

[0058] In the second embodiment, the recess-forming plate 152c is configured to be movable in the Z direction. The recess-forming plate 152c is formed, for example, from a single sheet of metal that can be removed from the fan cover 152 and is fixed at any position to the hood portion 152a, the bottom portion 152d, or the like using fastening members (not shown). Therefore, the height h2 in the Z1 direction of the sound suppression recess 152e formed by the inner surface of the hood portion 152a and the recess-forming plate 152c changes depending on the position at which the recess-forming plate 152c is fixed. In other words, the recess-forming plate 152c is fixed at a position that achieves the desired height h2 of the sound suppression recess 152e depending on the frequency and wavelength of the radiated sound s1 generated from the fan 51. The height h2 is an example of "the length of the portion of the first partition plate that forms the sound suppression recess" in the claims.

[0059] (Effects of the second embodiment) Next, the effects of the second embodiment will be described.

[0060] In the outdoor-installed power converter 101 of the second embodiment, as described above, the recess-forming plate 152c is configured so that the height h2, which is the length of the portion of the recess-forming plate 152c that constitutes the sound suppression recess 152e, is changeable. This makes it possible to change the height h2, which is the length of the sound suppression recess 152e, by changing the length of the portion of the recess-forming plate 152c that constitutes the sound suppression recess 152e. As a result, the length of the sound suppression recess 152e can be changed to an appropriate length depending on the wavelength of the radiated sound s1.

[0061] The other effects of the second embodiment are the same as those of the first embodiment.

[0062] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims rather than the above description of the embodiments, and further includes all modifications (variations) within the meaning and scope of the claims.

[0063] For example, in the above-described first and second embodiments, the outdoor-installed power conversion apparatus 100 is disposed outdoors, the hood portion 52a of the fan cover 52 constitutes the rain hood portion 52a that protects the fan 51 from rain, and the rain hood portion 52a has the sound suppression recess 52e formed therein. However, the present invention is not limited to this. In the present invention, the power conversion apparatus may be installed indoors, the hood portion 52a may constitute a dust hood, and the sound suppression recess 52e may be formed therein.

[0064] Furthermore, in the above first and second embodiments, an example was shown in which sound suppression recess 52e is arranged inside fan cover 52 so as to radiate reflected sound s2 from a position closer to intake port 10a than opening 52b of fan cover 52, but the present invention is not limited to this. In the present invention, sound suppression recess 52e may radiate reflected sound s2 from a position closer to opening 52b of fan cover 52 than intake port 10a, inside fan cover 52.

[0065] Furthermore, in the above first and second embodiments, an example was shown in which fan cover 52 includes sound guide plate 52f that guides radiated sound s1 generated from fan 51 toward sound suppression recess 52e, but the present invention is not limited to this. In the present invention, fan cover 52 may be provided with, for example, a cylindrical member or the like that guides radiated sound s1 generated from fan 51 toward sound suppression recess 52e instead of sound guide plate 52f, or it may not include a member that guides radiated sound s1 generated from fan 51 toward sound suppression recess 52e.

[0066] Furthermore, in the above first and second embodiments, an example was shown in which sound suppression recess 52e is configured to generate reflected sound s2 so that radiated sound s1 and reflected sound s2 interfere with each other at position P near the end of sound guide plate 52f on the sound suppression recess 52e side, but the present invention is not limited to this. In the present invention, sound suppression recess 52e may be arranged, for example, in the center of sound guide plate 52f in the extension direction so as to generate reflected sound s2 so that radiated sound s1 and reflected sound s2 interfere with each other.

[0067] In the first and second embodiments, the sound suppression recess 52e of the fan cover 52 includes the ventilation passage 52h that is provided to connect the intake port 10a and the opening 52b, and includes one sound suppression plate 52g that is provided to protrude into the ventilation passage 52h and is arranged to block the progress of the radiated sound s1. However, the present invention is not limited to this. In the present invention, a plurality of sound suppression plates 52g may be provided in the ventilation passage 52h.

[0068] Furthermore, in the first and second embodiments described above, examples have been shown in which the sound suppression recess 52e in the fan cover 52 is configured to extend in the Z direction along the ventilation passage 52h, but the present invention is not limited to this. In the present invention, the sound suppression recess 52e may be configured to extend in another direction, such as the Y direction, instead of the Z direction. For example, as in the fan cover 252 of the air supply unit 250 in FIG. 7 shown as a first modified example of the first embodiment, the sound suppression recess 252e may be formed by a recess-forming plate 252c that is provided to extend along the Z1-direction surface of the hood portion 252a, and may be configured to extend along the Z1-direction surface of the hood portion 252a.

[0069] In the first and second embodiments, sound suppression recess 52e is configured to have width w2 that is closer to opening width h1 of intake port 10a than opening width w1 of opening 52b, but the present invention is not limited to this. In the present invention, width w2 of sound suppression recess 52e only needs to be able to generate reflected sound s2, and may be, for example, smaller than opening width h1 of intake port 10a.

[0070] Furthermore, in the first and second embodiments described above, an example has been shown in which a plurality of fans 51 are provided and a fan cover 52 is provided corresponding to each of the plurality of fans 51, but the present invention is not limited to this. In the present invention, only one fan 51 may be provided, or one large fan cover 52 common to the plurality of fans 51 may be provided.

[0071] Furthermore, in the first and second embodiments described above, an example was shown in which one recess-forming plate 52c or the like is provided inside the fan cover 52. However, the present invention is not limited to this. In the present invention, multiple recess-forming plates 52c may be provided inside the fan cover 52. For example, as in the air supply unit 350 shown in FIG. 8, three plates, such as recess-forming plate 352c, recess-forming plate 452c, and recess-forming plate 552c, may be provided inside the fan cover 352. In this case, the recess-forming plate 352c, recess-forming plate 452c, recess-forming plate 552c, and the inner surface of the hood portion 352a form three sound suppression recesses 352e, 452e, and 552e, from which reflected sounds s2, s12, and s22 with different wavelengths (frequencies) are radiated, making it possible to muffle the three wavelengths (frequencies) included in the radiated sound s1 from the fan 51.

[0072] In the first and second embodiments, the fan cover 52 is made of a metal with relatively high corrosion resistance, such as aluminum, but the present invention is not limited to this. In the present invention, the fan cover 52 may be made of, for example, a resin with relatively high corrosion resistance and weather resistance.

[0073] Furthermore, in the first and second embodiments described above, an example has been shown in which fan 51 takes in air 200 through intake port 10a and sends cooling air through air outlet 51c to first cooling space 11 and second cooling space 12, but the present invention is not limited to this. In the present invention, fan 51 may be configured to suck in air 200 on the first cooling space 11 and second cooling space 12 side, thereby generating cooling air in first cooling space 11 and second cooling space 12, and expelling the heated air to the fan cover 52 side.

[0074] In the first and second embodiments, the fan cover 52 includes only the recess-forming plate 52c, the bottom 52d, the sound-guiding plate 52f, and the sound-suppressing plate 52g as integrally formed structures. However, the present invention is not limited to this. In the present invention, a separate member for improving the function of the air supply unit 50 may be disposed inside the fan cover 52. For example, a sound-absorbing material may be provided on the sound-suppressing plate 52g inside the fan cover 52. Furthermore, to prevent pressure loss when the fan 51 draws in the air 200, an acoustically transparent film may be provided in the space between the recess-forming plate 52c and the inner surface of the hood portion 52a. [Explanation of symbols]

[0075] 10. Cabinet 10a Air intake (intake and exhaust section) 20 Power conversion section 50 Air supply unit 51 fans 51a Rotating blade 52, 152, 252, 352 Fan Cover 52a, 152a, 252a, 352a Hood part (cover body, rain hood) 52b, 152b, 252b, 352b opening 52c, 152c, 252c, 352c, 452c, 552c Recess forming plate (first partition plate) 52d, 152d, 252d, 352d bottom 52e, 152e, 252e, 352e, 452e, 552e Sound suppression recesses 52f, 152f, 252f, 352f Sound guide plate (second partition plate) 52g, 152g, 252g, 352g Sound suppression plate (third partition plate) 52h, 152h, 252h, 352h ventilation duct 100, 101 Outdoor installation type power conversion device (power conversion device) s1 Radiated sound s2, s12, s22 reflected sounds w1 Width of the opening as seen from the X direction (second direction) w2 Width of the sound suppression recess as seen from the X direction (second direction) h1 Opening width of the intake port (intake / exhaust section) as seen from the X direction (second direction)

Claims

1. a housing that houses a power conversion unit that converts AC power and DC power; a fan disposed inside the housing and configured to cool the power conversion unit; a fan cover that covers an intake / exhaust section where air is taken in or exhausted by the fan, The fan is configured to take in or exhaust air through an opening provided below the fan cover, The fan cover includes a cover body and a first partition plate provided inside the cover body, and the first partition plate and the inner surface of the cover body form a sound suppression recess that radiates reflected sound to suppress radiated sound generated from the fan.

2. The power conversion device is disposed outdoors, The power conversion device according to claim 1 , wherein the cover body of the fan cover forms a rain hood that protects the fan from rain, and the sound suppression recess is formed inside the rain hood.

3. The power conversion device according to claim 1 , wherein the sound suppression recess is disposed inside the fan cover so as to radiate the reflected sound from a position closer to the intake and exhaust section than the opening of the fan cover.

4. The power conversion device according to claim 1 , wherein the fan cover includes a second partition plate that guides the radiated sound generated from the fan toward the sound suppression recess.

5. The power conversion device according to claim 4, wherein the sound suppression recess is configured to generate the reflected sound so that the radiated sound and the reflected sound interfere with each other at a position near the end of the second partition plate on the sound suppression recess side.

6. 5. The power conversion device according to claim 4, wherein the fan cover is provided to connect the intake and exhaust section and the opening, includes an air passage through which air taken in or exhausted by the fan passes, and includes a third partition plate that is provided to protrude into the air passage and is positioned to prevent the radiated sound from traveling.

7. the fan cover is provided to connect the intake and exhaust unit and the opening, and includes a ventilation path through which air taken in or exhausted by the fan passes; The power conversion device according to claim 2 , wherein the sound suppression recess is configured to extend in the vertical direction along the ventilation passage.

8. 3. The power conversion device according to claim 2, wherein the width of the sound suppression recess as viewed from a second direction perpendicular to both the first direction in which the fan and the fan cover are aligned and the vertical direction is closer to the opening width of the intake and exhaust section as viewed from the second direction than to the opening width of the opening as viewed from the second direction.

9. The power conversion device according to claim 2 , wherein the first partition plate is configured so that a length of a portion of the first partition plate that forms the sound suppression recess is changeable.

10. A plurality of the fans are provided, The power conversion device according to claim 2 , wherein the fan cover is provided corresponding to each of the plurality of fans.

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