Power supply unit for ozone generator

Abstract

To provide a power supply device for an ozone generator that can prevent condensation on the outer surface of the control panel enclosure. [Solution] The power supply unit 50 for the ozone generator supplies power to the ozone generator 2, which generates ozone from an oxygen-containing gas by silent discharge. The power supply unit 50 for the ozone generator comprises a main heating element 12 including a transformer, an inverter, and a reactor, and a heat exchanger 11 that cools the air flowing through the inside of the enclosure 20 with cooling water. At least one of the transformer, inverter, and reactor, and the heat exchanger 11 are arranged inside the enclosure 20. An electrically driven valve 16 that controls the flow rate of cooling water entering and leaving the heat exchanger 11 is connected to the heat exchanger 11, and the opening and closing of the electrically driven valve 16 is controlled by a control unit 13.

Description

Technical Field

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[0001] The present disclosure relates to a power supply device for an ozone generator that generates ozone from a gas containing oxygen by silent discharge.

Background Art

[0002] A general power supply device for an ozone generator includes a transformer, a reactor, and an inverter. Conventional power supply devices for ozone generators that supply, for example, 100 kW or more of power have larger capacities of the transformer, reactor, and inverter, and the heat generation density of these devices becomes high For this reason, the inside of the board housing in which these devices are accommodated may be cooled using a heat exchanger. Patent Document 1 below discloses a power supply device for an ozone generator having a small and simple structure in which the arrangement and cooling of the devices inside the board housing are optimized.

Prior Art Documents

Patent Documents

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Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the case of a power supply device for an ozone generator having a structure in which the inside of the board housing is cooled using a heat exchanger, when the temperature of the supplied cooling water is low, the outside surface of the board housing may be dew - condensed due to the cooling of the inside of the board housing. Although the power supply device for an ozone generator described in Patent Document 1 also mentions the dew condensation on the outside surface of the board housing, it is not guaranteed to prevent the dew condensation on the outside surface of the board housing. <00OOО27> The present disclosure has been made in view of the above, and an object thereof is to obtain a power supply device for an ozone generator that can prevent dew condensation on the outer surface of the board housing. <000002九]]

Means for Solving the Problems

[0006] To solve the aforementioned problems and achieve the objectives, the power supply unit for an ozone generator according to this disclosure is a power supply unit for an ozone generator that supplies power to an ozone generator that generates ozone from an oxygen-containing gas by silent discharge. The power supply unit for an ozone generator comprises a transformer that transforms the voltage from a commercial AC power source, an inverter that converts the AC voltage transformed by the transformer into a higher frequency AC voltage, and a reactor connected to the output of the inverter. The power supply unit for an ozone generator also comprises a panel enclosure, which is a housing that accommodates at least one of the transformer, inverter, and reactor. A heat exchanger is arranged inside or adjacent to the outside of the panel enclosure to cool the air flowing through the inside of the panel enclosure with cooling water. At least one of the transformer, inverter, and reactor, which is housed inside the panel enclosure, is cooled by the air flowing through the inside of the panel enclosure. An electrically driven valve is connected to the heat exchanger to control the flow rate of cooling water entering and leaving the heat exchanger, and the opening and closing of the electrically driven valve is controlled by a control unit. [Effects of the Invention]

[0007] The power supply device for ozone generators described herein has the effect of preventing condensation on the outer surface of the control panel enclosure. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example of the configuration of an ozone generator, including a power supply unit for the ozone generator according to Embodiment 1. [Figure 2] Internal side view of the power supply unit for an ozone generator according to Embodiment 1, viewed from the left side. [Figure 3] Internal side view from the left side of an example configuration of the power supply unit for an ozone generator according to Embodiment 1, which differs from that shown in Figure 2. [Figure 4] Figure 2 illustrates the preferred monitoring location for the air temperature inside the control panel of the ozone generator power supply unit. [Figure 5] Figure 3 illustrates the preferred monitoring location for the air temperature inside the control panel of the ozone generator power supply unit. [Figure 6] Flowchart illustrating the operation of the control unit in Embodiment 1 [Figure 7] Block diagram showing an example of a hardware configuration that realizes the functions of the control unit in Embodiment 1. [Figure 8] Block diagram showing another example of a hardware configuration that realizes the functions of the control unit in Embodiment 1. [Figure 9] Internal side view of the power supply unit for an ozone generator according to Embodiment 2, viewed from the left side. [Figure 10] Figure 1 illustrating the operation of the power supply device for an ozone generator according to Embodiment 3. [Figure 11] Figure 2 illustrating the operation of the power supply device for the ozone generator according to Embodiment 3. [Modes for carrying out the invention]

[0009] The power supply device for an ozone generator according to the embodiment of this disclosure will be described in detail below with reference to the attached drawings. Note that in the attached drawings, the scale of each component may differ from the actual scale for ease of understanding or for drawing convenience.

[0010] Embodiment 1. Figure 1 shows an example configuration of an ozone generator 100 including a power supply unit 50 for the ozone generator according to Embodiment 1. The power supply unit 50 for the ozone generator is a power supply unit that supplies power to the ozone generator 2. The ozone generator 2 is a device that generates ozone from an oxygen-containing gas by silent discharge. As shown in Figure 1, the ozone generator 100 includes the ozone generator 2 and the power supply unit 50 for the ozone generator, and is further configured to include a chiller 1, a flow control valve 4, a cooling water circulation pump 5, and a flow meter 6.

[0011] Chiller 1 is a cooling device that cools the ozone generator 2. Chiller 1 cools the ozone generator 2 by circulating cooling water into and out of the ozone generator 2. The cooling water that is circulated into and out of the ozone generator 2 is circulated by the cooling water circulation pump 5.

[0012] The power supply unit 50 for the ozone generator comprises a heat exchanger 11, a main heating element 12, a control unit 13, a fan 14, and a temperature detector 15 as the main components for supplying the required power to the ozone generator 2. Examples of the main heating element 12 include transformers, inverters, and reactors. The heat exchanger 11, the main heating element 12, the control unit 13, the fan 14, and the temperature detector 15 are housed inside the enclosure 20. The enclosure 20 is an enclosure that forms a housing space for housing these components.

[0013] Note that while Figure 1 shows an example where the control unit 13 is housed inside the control panel enclosure 20, the system is not limited to this example. The control unit 13 may be located outside the control panel enclosure 20. For example, a control panel may be provided next to the control panel enclosure 20 as a row panel, and the control unit 13 may be installed in that control panel. Alternatively, the control unit 13 may be located at a distance that allows for signal transmission and reception.

[0014] The power supply unit 50 for the ozone generator has a main heat-generating element 12 and therefore requires cooling. As shown in Figure 1, the power supply unit 50 for the ozone generator according to Embodiment 1 is configured such that a portion of the cooling water supplied from the chiller 1 to the ozone generator 2 is branched off and flows in and out. In other words, the power supply unit 50 for the ozone generator according to Embodiment 1 is configured to reuse the cooling water supplied to the ozone generator 2 and does not have a separate cooling device specifically for the power supply unit 50.

[0015] The flow rate adjustment valve 4 is a manual adjustment valve. At the initial stage of operation of the power supply device 50 for the ozone generator, the flow rate is manually set so that the cooling water flowing in and out of the heat exchanger 11 of the power supply device 50 for the ozone generator reaches a specified flow rate. The flow rate of the cooling water can be confirmed by the flow meter 6. On the other hand, during the operation of the power supply device 50 for the ozone generator, the flow rate of the cooling water flowing in and out of the heat exchanger 11 is controlled by opening and closing the electric drive valve 16 connected to the heat exchanger 11 via a pipe. The opening and closing of the electric drive valve 16 are controlled by the control unit 13. Examples of the electric drive valve 16 include a solenoid valve driven by a solenoid (electromagnet) and an electric valve driven by a motor. Either the solenoid valve or the electric valve may be used, but the solenoid valve is preferred in terms of instantaneous operation and relatively low cost.

[0016] In addition, in FIG. 1, the flow rate adjustment valve 4 and the electric drive valve 16 are shown as separate bodies, but the flow rate adjustment valve 4 and the electric drive valve 16 may be integrally configured. That is, in the configuration of FIG. 1, the flow rate adjustment valve 4 may be omitted, and a configuration including only the electric drive valve 16 controlled by the control unit 13 may be used.

[0017] In the power supply device 50 for the ozone generator, the white arrow shown in the panel housing 20 indicates the flow of air in the panel housing 20. This air flow is caused by the fan 14 and flows into the heat exchanger 11. The heat exchanger 11 cools the incoming air with the cooling water. As a result, the air flowing through the inside of the panel housing 20 is cooled by the cooling water flowing in and out of the heat exchanger 11.

[0018] The temperature sensor 15 monitors the internal air temperature, which is the temperature of the air flowing through the inside of the enclosure 20, and outputs the monitoring result to the control unit 13. The control unit 13 controls the opening and closing of the electric drive valve 16 based on the monitoring result from the temperature sensor 15. As described above, the flow rate of cooling water flowing into and out of the heat exchanger 11 is controlled by the opening and closing of the electric drive valve 16. That is, in the power supply device 50 for the ozone generator according to Embodiment 1, the control unit 13 controls the flow rate of cooling water by controlling the opening and closing of the electric drive valve 16 based on the internal air temperature. Note that flow rate control includes flow / stop control, i.e., ON / OFF control.

[0019] Figure 2 is an internal side view of the ozone generator power supply unit 50 according to Embodiment 1, viewed from the left side. In Figure 2, the heat exchanger 11 and fan 14, which were explained using Figure 1, are shown inside the panel enclosure 20. Also in Figure 2, a transformer 121, an inverter 122, and a reactor 123 are shown as examples of the main heat-generating elements 12 explained in Figure 1. The transformer 121 transforms the voltage from the commercial AC power supply. The inverter 122 converts the AC voltage transformed by the transformer 121 into an AC voltage of a higher frequency. The reactor 123 is connected to the output of the inverter 122. The ozone generator 2, which utilizes silent discharge, is capacitive as a load for the ozone generator power supply unit 50. For this reason, an inductive reactor 123 is usually provided on the output side of the inverter 122.

[0020] Next, the arrangement of each component will be described according to the example in Figure 2. First, the heat exchanger 11 is located on the lower side inside the enclosure 20. The heat exchanger 11 is positioned at a downward slope from the front to the back of the enclosure 20. The angle of inclination is preferably 45 degrees or less with respect to the horizontal direction, and even more preferably 25 degrees or less, so as not to increase the space occupied by the heat exchanger 11.

[0021] On the other hand, the transformer 121, inverter 122, and reactor 123 are located on the upper side inside the panel enclosure 20.

[0022] The transformer 121 and inverter 122 are components that generate a lot of heat. Furthermore, the inverter 122 contains semiconductor elements, and sufficient cooling is necessary to prevent damage to these elements. Considering these points, the transformer 121 and inverter 122 are positioned directly above the heat exchanger 11. This arrangement allows the transformer 121 and inverter 122 to be cooled by the coolest airflow within the enclosure 20.

[0023] Furthermore, the reactor 123 is positioned above the transformer 121 and inverter 122, and is cooled using the cooling air after the transformer 121 and inverter 122 have been cooled. A reactor mounting plate (not shown) is provided below the reactor 123, and an opening is provided in the portion of the reactor mounting plate below the reactor 123 to allow cooling air to flow through. Although the temperature of the cooling air hitting the reactor 123 rises, the reactor 123 can be sufficiently cooled because it can be cooled using much of the cooling air flowing inside the enclosure 20.

[0024] A heat exchanger mounting plate 17 is provided directly above the heat exchanger 11 to cover the gap between the panel enclosure 20 and the heat exchanger 11. The heat exchanger mounting plate 17 is installed so that the cooling air introduced into the lower part of the panel enclosure 20 from the return air passage 19 flows through the heat exchanger 11 to the upper part of the panel enclosure 20. The return air passage 19 is an air passage for circulating the air inside the panel after the transformer 121, inverter 122 and reactor 123 have been cooled.

[0025] The fan 14 is positioned inside the front panel 22. A grounded protective panel 18 is placed between the fan 14 and the inverter 122. The return air passage 19 is formed by the protective panel 18 and the front panel 22 of the enclosure 20.

[0026] High voltage is applied to the inverter 122, but by providing a grounded protective panel 18, it is possible to prevent workers from accidentally touching residual high voltage, for example, when replacing the fan 14. In addition, the protective panel 18 and the front panel 22 of the enclosure 20 form a return air passage 19, eliminating the need for special structural members dedicated to the air passage. This makes it possible to miniaturize, simplify, and reduce the cost of the enclosure 20.

[0027] The transformer 121 is positioned, for example, about 5 mm to 50 mm away from the inner surface of the rear panel 21. This arrangement allows the rear panel 21 of the enclosure 20 to be used as a partition for the airflow path, enabling cooling air to be actively directed to the interior or exterior surface of the transformer 121. Furthermore, the distance between the transformer 121 and the inverter 122, and the distance between the inverter 122 and the protective panel 18, are also positioned about 5 mm to 50 mm apart. This arrangement allows the space between the transformer 121 and the inverter 122, and the front side of the inverter 122, to be used as airflow paths, enabling cooling air to be actively directed to the interior and exterior surfaces of both the transformer 121 and the inverter 122. It goes without saying that the distance between the rear panel 21 of the enclosure 20 and the transformer 121 should be at least the length required for insulation, taking into account the voltage applied to the transformer 121.

[0028] Note that the configuration in Figure 2 is just one example, and the arrangement of the components in the power supply unit 50 for the ozone generator according to Embodiment 1 is not limited to the example in Figure 2. For example, in Figure 2, the fan 14 is located on the front panel 22 side, but the fan 14 may be located on the rear panel 21 side. Alternatively, the fan 14 may be located on the right side panel side or the left side panel side, which are not shown in Figure 2.

[0029] Furthermore, Figure 2 illustrates a configuration in which the transformer 121, inverter 122, and reactor 123 are arranged on the upper side of the interior of the enclosure 20, and the heat exchanger 11 is arranged on the lower side of the interior of the enclosure 20, but the configuration is not limited to this. For example, the heat exchanger 11 may be arranged in the position of the fan 14 in Figure 2, and the fan 14 may be arranged above the heat exchanger 11. This configuration is shown in Figure 3. Figure 3 is an internal side view of the interior of an example of a configuration different from Figure 2 of the ozone generator power supply device 50 according to Embodiment 1, viewed from the left side. In Figure 3, the same or equivalent components as in Figure 2 are denoted by the same reference numerals as in Figure 2. Also, in Figure 3, as in Figure 2, the airflow inside the enclosure 20 is indicated by white arrows.

[0030] In the configuration shown in Figure 3, the protective panel 18 is unnecessary, and a panel 40, which forms part of the enclosure 20, is located in the position where the protective panel 18 would normally be. An opening 41 is provided at the top of panel 40, and an opening 42 is provided at the bottom of panel 40. In Figure 3, a new enclosure 44 for forming a return air passage 19 is installed outside panel 40, i.e., adjacent to the enclosure 20. The fan 14 is installed in the opening 41 provided at the top of panel 40. The heat exchanger 11 is installed inside the new enclosure 44 for forming the return air passage 19, and a heat exchanger mounting plate 17 blocks the entrance to the gap around the heat exchanger 11 so that the air inside the enclosure that has passed through the opening 41 does not flow into the gap around the heat exchanger 11. The air inside the enclosure circulates between the enclosure 20 and the enclosure 44 through openings 41 and 42.

[0031] In Figures 2 and 3, an example configuration is shown in which the transformer 121, inverter 122, and reactor 123 are all housed inside the enclosure 20. However, a configuration in which at least one of the transformer 121, inverter 122, and reactor 123 is housed inside the enclosure 20 is also possible. In other words, the main heat-generating element 12 that is cooled by the air flowing through the inside of the enclosure 20 may be at least one of the transformer 121, inverter 122, and reactor 123.

[0032] Furthermore, while Figures 2 and 3 illustrate a case where the transformer 121, inverter 122, and reactor 123 are composed of a single unit, each of these components may be composed of multiple units.

[0033] Figure 4 is a diagram illustrating preferred monitoring locations for the air temperature inside the control panel in the ozone generator power supply unit 50 shown in Figure 2. Figure 4 shows space 26 indicating preferred monitoring locations for the air temperature inside the control panel, space 27 indicating more preferred monitoring locations for the air temperature inside the control panel, and space 30 indicating even more preferred monitoring locations for the air temperature inside the control panel. Space 30 is shown with fine hatching, and space 27 is shown with coarse hatching. Space 27 includes the area of ​​space 30, and space 26 includes the areas of space 27 and space 30. In this paper, to distinguish spaces 26, 27, and 30 without coding, space 26 may be referred to as the "first space," space 27 as the "second space," and space 30 as the "third space."

[0034] In Embodiment 1, a temperature detector 15 is installed in space 26 to monitor the air temperature inside the panel. In the example shown in Figure 4, the temperature detector 15 is installed in space 27.

[0035] Space 26 is located inside the enclosure 20 and is formed above the uppermost end of the main heat-generating portion of the main heat-generating element 12, which includes the transformer 121, inverter 122, and reactor 123. It is a space in a cross-section where the return air passage 19 for circulating the air inside the enclosure after cooling the main heat-generating element 12 is viewed to the right or left. Here, the main heat-generating portion of the main heat-generating element 12 is defined as the portion whose heat generation is, for example, 10% or more of the total heat generation of the main heat-generating element 12. That is, even if a portion such as a protrusion whose heat generation is less than 10% of the total is included in space 26, that portion is not considered a main heat-generating portion. Therefore, such a portion may be located in space 26. Note that 10% is just an example and is not limited to this value. For example, 8% or 12% may be used instead of 10%.

[0036] To prevent condensation on the outer surface of the enclosure 20, one possible method is to monitor the temperature of the area where condensation is to be prevented and control the cooling water so that the temperature of that area is 1-2°C higher than the dew point temperature. In other words, a method is conceivable to control the temperature of the area where condensation is to be prevented to be slightly higher than the dew point temperature. However, with this method, it is not possible to understand the temperature behavior of the main heat-generating element 12 that is being cooled, so there is a problem that the main heat-generating element 12 may overheat due to an unexpected temperature rise, reducing its lifespan.

[0037] In contrast, the method of Embodiment 1 involves setting the monitoring position for the air temperature inside the panel to be above the uppermost end of the main heat-generating part of the main heat-generating element 12, which includes the transformer 121, inverter 122, and reactor 123. This method allows monitoring of the air temperature inside the panel after it has passed through the main heat-generating element 12, which is the object to be cooled. In other words, the method of Embodiment 1 is a method of controlling the cooling water by monitoring the temperature at a location that can reflect the temperature behavior of the main heat-generating element 12. Space 26 is the location that can most comprehensively reflect the temperature behavior of the main heat-generating element 12, including when there are multiple main heat-generating elements 12. On the other hand, the temperature of the lower part of the rear side of the panel enclosure 20, where condensation is most likely to occur, is affected by both the cooling water temperature and the air temperature entering the heat exchanger 11 when cooling water is flowing, and by the air temperature entering the heat exchanger 11 when cooling water is not flowing. In the airflow inside the panel, there is no main heat-generating element 12 downstream of space 26, so the temperature of space 26 is approximately equal to the air temperature entering the heat exchanger 11. In other words, when the temperature detector 15 is placed in space 26, the temperature detector 15 can acquire temperature information that affects both the temperature of the main heat-generating element 12 and the temperature of the lower part of the rear side of the enclosure 20, where condensation is most likely to occur. Therefore, the power supply device 50 for the ozone generator according to Embodiment 1 has the effect of preventing overheating of the main heat-generating element 12 and preventing condensation of the enclosure 20.

[0038] Furthermore, the second space, space 27, indicates a more favorable monitoring location for the internal air temperature of the control panel than the first space, space 26. Space 27 is space 26, but located within the control panel enclosure 20 on the side of the return air passage 19, relative to the vertical virtual plane 28 that divides the space containing the main heat-generating elements 12 (excluding the return air passage 19) into left and right halves; in other words, it is space within the control panel enclosure 20 on the fan 14 side of the virtual plane 28. It is thought that air passing through the reactor 123 and heading towards the return air passage 19 passes through space 27 more often than air passing through space 26, which does not include space 27. For this reason, space 27 can be considered a location that better reflects the temperature behavior of the main heat-generating elements 12 than space 26.

[0039] Furthermore, the third space, space 30, indicates a more preferable monitoring location for the air temperature inside the control panel than the second space, space 27. Space 30 is the space inside the control panel 20 that is on the return air passage 19 side of the virtual plane 31 parallel to the vertical virtual plane 28 at the position on the return air passage 19 side of the outer casing of the main heat-generating element 12 (reactor 123 in the example of Figure 4) located at the top of the control panel 20, that is, the space inside the control panel 20 that is on the fan 14 side of the virtual plane 31. Air that passes through reactor 123 and heads towards the return air passage 19 will ultimately always pass through space 30. For this reason, space 30 can be considered a location that can reflect the temperature behavior of the main heat-generating element 12 better than space 27. In this paper, in order to distinguish virtual planes 28 and 31 without coding, virtual plane 28 may be called the "first virtual plane" and virtual plane 31 may be called the "second virtual plane".

[0040] In addition, the power supply unit 50 for the ozone generator may conventionally be equipped with a temperature sensor, for example, for the purpose of an alarm. In this case, if the temperature sensor is located in a place where it can reflect the temperature behavior of the main heat-generating element 12 that is to be cooled, the temperature sensor may be used instead of the temperature sensor 15.

[0041] Figure 5 is a diagram illustrating preferred monitoring locations for the air temperature inside the control panel in the ozone generator power supply unit 50 shown in Figure 3. Similar to Figure 3, Figure 5 shows a space 26 indicating a preferred monitoring location for the air temperature inside the control panel, a space 27 indicating a more preferred monitoring location for the air temperature inside the control panel with coarse hatching, and a space 30 indicating an even more preferred monitoring location for the air temperature inside the control panel with fine hatching. In Figure 5, an example is shown in which the temperature detector 15 is installed in space 30, but the concept regarding the monitoring location for the air temperature inside the control panel is the same as in the ozone generator power supply unit 50 shown in Figure 4, and it may be installed in any of spaces 26, 27, or 30.

[0042] Next, the operation of the control unit 13 in Embodiment 1 will be described with reference to Figure 6. Figure 6 is a flowchart illustrating the operation of the control unit 13 in Embodiment 1. For the purposes of explaining Figure 6, the environmental conditions in the specifications are assumed to be an air temperature of 30°C and a relative humidity of 85%, with a dew point temperature of 27.5°C under these environmental conditions. Furthermore, it is assumed that the electric drive valve 16 is controlled to be closed when the ozone generator power supply unit 50 is stopped.

[0043] First, when the ozone generator power supply unit 50 is started while the electric drive valve 16 remains closed, no cooling water flows, and the temperature of the air inside the panel rises due to the heat generated by the main heat-generating element 12. The control unit 13 determines whether the temperature of the air inside the panel is 40°C or higher (step S11). If the temperature of the air inside the panel is less than 40°C (step S11, No), the control unit 13 returns to step S11 and repeats the process of step S11. In other words, the process of step S11 is repeated until the temperature of the air inside the panel reaches 40°C or higher. If the temperature of the air inside the panel is 40°C or higher (step S11, Yes), the control unit 13 controls the electric drive valve 16 to open (step S12). Note that in step S11, the determination is "Yes" when the temperature of the air inside the panel is 40°C, but it may also be determined as "No". That is, the determination may be either "Yes" or "No" when the temperature of the air inside the panel and the determination value of 40°C are equal.

[0044] When the electrically driven valve 16 opens, cooling water flows to the heat exchanger 11, and the air temperature inside the panel decreases. The control unit 13 determines whether the air temperature inside the panel is 39°C or lower (step S13). If the air temperature inside the panel is above 39°C (step S13, No), the control unit 13 returns to step S13 and repeats the process in step S13. In other words, the process in step S13 is repeated until the air temperature inside the panel is 39°C or lower. If the air temperature inside the panel is 39°C or lower (step S13, Yes), the control unit 13 controls the electrically driven valve 16 to close (step S14). Note that in step S13, the determination is "Yes" when the air temperature inside the panel is 39°C, but it may also be determined as "No". That is, the determination may be either "Yes" or "No" when the air temperature inside the panel and the determination value of 39°C are equal.

[0045] When the electrically driven valve 16 closes, cooling water stops flowing to the heat exchanger 11, causing the air temperature inside the panel to rise. The control unit 13 checks for the presence of an interrupt (step S15), and if there is an interrupt (step S15, Yes), it terminates the process shown in Figure 6. If there is no interrupt (step S15, No), the control unit 13 returns to step S11 and repeats the processes from steps S11 to S15.

[0046] Let's elaborate on the process shown in Figure 6. According to the process in Figure 6, when the air temperature inside the panel reaches 40°C, the electrically driven valve 16 opens and cooling water begins to flow. As the cooling water flows, the air temperature inside the panel decreases, and the cooling water continues to flow until the air temperature inside the panel reaches 39°C. At this point, the electrically driven valve 16 closes and the cooling water stops. Once the cooling water stops, the air temperature inside the panel rises and eventually reaches 40°C. These processes are then repeated.

[0047] If the load on the ozone generator power supply unit 50 is very low, or if the air temperature inside the panel does not reach 40°C, the electric drive valve 16 can remain closed without issue. It has been confirmed that the internal temperature of the main heating element 12 is below the permissible upper limit temperature until the air temperature inside the panel reaches 40°C. Furthermore, if the air temperature inside the panel is 39°C or higher, it has been confirmed that the temperature on any part of the outer surface of the panel enclosure 20, especially the lower part of the rear panel 21 where condensation is most likely to occur, is 28.5°C or higher. As described above, since the dew point temperature is 27.5°C, condensation does not occur. In addition, when starting the ozone generator power supply unit 50 from a stopped state, there is a period in Figure 6 from the start to step S11 during which the air temperature inside the panel is 39°C or lower. However, since cooling water does not flow during this period due to logic, condensation does not occur even if the air temperature inside the panel is 39°C or lower.

[0048] Figure 6 shows an example where the control temperature difference of the air temperature inside the panel is set to 1.0°C (=40-39°C), but this is just one example and is not limited to this example. The control temperature difference of the air temperature inside the panel can preferably be set to 0.3°C or more and 2°C or less, more preferably 0.5°C or more and 1.5°C or less, and even more preferably 0.7°C or more and 1.2°C or less.

[0049] If the controlled temperature difference of the air temperature inside the panel is too small, the electric drive valve 16 will open and close more frequently, shortening its lifespan. Conversely, if the controlled temperature difference is too large, the electric drive valve 16 will remain open for longer periods, causing the panel enclosure 20 to cool too much and making condensation more likely. The above setting value for the controlled temperature difference takes these considerations into account, making it possible to extend the lifespan of the electric drive valve 16 while preventing condensation on the panel enclosure 20.

[0050] Figure 7 is a block diagram showing an example of a hardware configuration that realizes the functions of the control unit 13 in Embodiment 1. When realizing some or all of the functions of the control unit 13 in Embodiment 1, the configuration can include a processor 300 that performs calculations, a memory 302 that stores the program read by the processor 300, and an interface 304 that performs signal input and output, as shown in Figure 7. The functions including the processor 300, memory 302, and interface 304 may be configured using, for example, a programmable logic controller (PLC).

[0051] The processor 300 is an example of a computing means. The processor 300 may be a computing means referred to as a microprocessor, microcomputer, CPU (Central Processing Unit), or DSP (Digital Signal Processor). The memory 302 may also include non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), and EEPROM (Electrically EPROM), as well as magnetic disks, optical disks, compact disks, minidiscs, and DVDs (Digital Versatile Discs).

[0052] Memory 302 stores a program that performs the functions of the control unit 13 in Embodiment 1. The processor 300 can perform the above-described processing by exchanging necessary information via interface 304, executing the program stored in memory 302, and referring to the table stored in memory 302. The calculation results by the processor 300 can be stored in memory 302.

[0053] Furthermore, when implementing only a portion of the functions of the control unit 13 in Embodiment 1, the configuration shown in Figure 8 may also be used. Figure 8 is a block diagram showing another example of a hardware configuration that implements the functions of the control unit 13 in Embodiment 1. In Figure 8, the processor 300 and memory 302 shown in Figure 5 are replaced by the processing circuit 303.

[0054] The processing circuit 303 may be a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. Information input to and output from the processing circuit 303 can be exchanged via the interface 304.

[0055] Alternatively, some of the processing in the control unit 13 may be performed by the processing circuit 303, while the processing not performed by the processing circuit 303 may be performed by the processor 300 and memory 302.

[0056] As described above, in the power supply device 50 for an ozone generator according to Embodiment 1, the transformer 121, inverter 122, and reactor 123 are arranged on the upper side inside the enclosure 20, which is the housing that houses them, and a heat exchanger 11 is arranged on the lower side inside the enclosure 20 to cool the air flowing through the inside of the enclosure 20 with cooling water. An electrically driven valve 16 is connected to the heat exchanger 11 to control the flow rate of cooling water entering and leaving the heat exchanger 11, and the opening and closing of the electrically driven valve 16 is controlled by a control unit 13. With the power supply device 50 for an ozone generator configured in this way, the first space formed on the upper side of the transformer 121, inverter 122, and reactor 123 inside the enclosure 20 can be set as a monitoring position for the air temperature inside the enclosure, and the opening and closing of the electrically driven valve 16 is controlled based on the monitoring result of the air temperature inside the enclosure in this first space, so that condensation on the outer surface of the enclosure 20 can be prevented.

[0057] Embodiment 2. Figure 9 is an internal side view of the ozone generator power supply unit 50 according to Embodiment 2, viewed from the left side. The difference from the ozone generator power supply unit 50 according to Embodiment 1 shown in Figure 2 is the position of the temperature detector 15. Specifically, in the ozone generator power supply unit 50 shown in Figure 9, the temperature detector 15 is placed in the return air passage 19 formed by the protective panel 18 and the front panel 22 of the enclosure 20. In the example in Figure 9, the temperature detector 15 is placed on the exhaust side of the fan 14, but the example is not limited to this. The temperature detector 15 may also be placed on the intake side of the fan 14.

[0058] The air that has passed through the main heat-generating elements 12, including the transformer 121, inverter 122, and reactor 123, which are to be cooled, flows through the return air passage 19. Therefore, the return air passage 19 can be said to be a place that can reflect the temperature behavior of the main heat-generating elements 12. Accordingly, by placing the temperature detector 15 in the return air passage 19, the temperature detector 15 can obtain temperature information that affects both the temperature of the main heat-generating elements 12 and the temperature of the lower part of the rear side of the enclosure 20, where condensation is most likely to occur. Accordingly, the power supply device 50 for the ozone generator according to Embodiment 2 has the effect of preventing overheating of the main heat-generating elements 12 and preventing condensation of the enclosure 20, similar to the power supply device 50 for the ozone generator according to Embodiment 1.

[0059] In this example, the temperature detector 15 is positioned in the return air passage 19 of the ozone generator power supply unit 50 shown in Figure 2, but the system is not limited to this example. The temperature detector 15 may also be positioned on the exhaust side or intake side of the return air passage 19 of the ozone generator power supply unit 50 shown in Figure 3. In any configuration, it is possible to enjoy the effects of the above-described embodiment 2.

[0060] Embodiment 3. Embodiment 3 describes an ozone generator power supply unit 50 that achieves the same effects as Embodiments 1 and 2 without using a temperature detector 15. The configuration of the ozone generator power supply unit 50 according to Embodiment 3 is the same as that of Embodiments 1 and 2, except that it does not have a temperature detector 15.

[0061] Figure 10 is the first diagram illustrating the operation of the ozone generator power supply unit 50 according to Embodiment 3. Figure 10 shows in table format the electric drive valve opening time and electric drive valve closing time set in accordance with the load factor of the ozone generator power supply unit 50. In Figure 10, the load factor is the ratio of the power output from the ozone generator power supply unit 50 to the load, which is the ozone generator 2, to the rated power of the ozone generator power supply unit 50. Note that the load factor may be defined based on the maximum power that the ozone generator power supply unit 50 can output, rather than the rated power. The setting values ​​shown in Figure 10 can be stored in the control unit 13.

[0062] In Figure 10, for example, when the load factor is constant at 100%, the electric drive valve 16 is controlled to be open for 350 seconds and closed for 60 seconds, and these controls are repeated.

[0063] Figure 11 is a second diagram illustrating the operation of the ozone generator power supply unit 50 according to Embodiment 3. Figure 11 shows an example of operation when the unit is actually operated using the settings in Figure 10, with the load factor shown at the top and the open / closed state of the electric drive valve 16 shown at the bottom. Note that Figure 11 takes into account the case where the load factor is not constant but changes during control by the control unit 13. The operation example in Figure 11 will be described below.

[0064] First, in Figure 11, the load factor at time 0 seconds is 45%. Since the open setting value for a 45% load factor in Figure 10 is 100 seconds, the electric drive valve 16 is kept open for 100 seconds before being closed. If the load factor does not change, the closed setting value for a 45% load factor is 400 seconds, so the closed state continues for 400 seconds. On the other hand, in the example in Figure 11, the load factor changes to 55% at time 300 seconds, so the electric drive valve 16 is controlled to be closed for 350 seconds. Of the 350 seconds, 200 seconds is the elapsed time from 100 seconds when the electric drive valve 16 was closed to 300 seconds when the load factor changed to 55%, i.e., 300 - 100 = 200 seconds. The remaining 150 seconds of the 350 seconds are calculated as 300 seconds * (1 / 2) = 150 seconds. 300 seconds is the closed setting value for a 55% load factor. Furthermore, (1 / 2) is the remaining ratio of elapsed time, which is the value obtained by subtracting the elapsed time ratio from 1. Of the 400 seconds set for closing at a load factor of 45%, 200 seconds have elapsed by the time the load factor changes to 55%, so the elapsed time ratio is 200 / 400 = 1 / 2, and the remaining ratio of elapsed time is 1 - (1 / 2) = 1 / 2. By multiplying this remaining ratio by 300 seconds, the aforementioned 150 seconds can be calculated. In this way, the electric drive valve 16 remains closed for 350 seconds, from 100 seconds to 450 seconds.

[0065] 450 seconds after the start of control, the electric drive valve 16 is controlled to be in the open state, and this open time can be calculated in the same way as above. In the example in Figure 11, the load factor changes to 65% 500 seconds after the start of control, so the electric drive valve 16 is controlled to be in the open state for 183 seconds. Of the 183 seconds, 50 seconds is the elapsed time from 450 seconds when the electric drive valve 16 was in the open state to 500 seconds when the load factor changed to 65%, i.e., 500 - 450 = 50 seconds. The remaining 133 seconds of the 183 seconds are calculated as 200 seconds * (2 / 3) ≈ 133 seconds. 200 seconds is the open setting value for a load factor of 65%, and (2 / 3) is the remaining percentage of the elapsed time. Of the 150 seconds set for the open state at a load factor of 55%, 50 seconds have elapsed by the time the load factor changes to 65%. Therefore, the ratio of elapsed time is 50 / 150 = 1 / 3, and the remaining ratio of elapsed time is 1 - (1 / 3) = 2 / 3. By multiplying this remaining ratio by 200 seconds, we can calculate the aforementioned 133 seconds. In this way, the electric drive valve 16 remains open for 183 seconds from time 450 seconds, or until time 633 seconds.

[0066] After that, since the load factor does not change, the opening and closing of the electric drive valve 16 is controlled by the set closing time of 200 seconds when the load factor is 65% and the set opening time of 200 seconds when the load factor is 65%.

[0067] As described above, when the load factor changes during control by the control unit 13, the opening and closing time of the electric drive valve 16 is first calculated by considering the electric drive valve opening time or electric drive valve closing time for each load factor category as 100%. Then, even if the load factor changes, the percentage of time for which the electric drive valve 16 is controlled to be open or closed at each load factor is accumulated, and the electric drive valve opening time or electric drive valve closing time until the accumulated time reaches 100% is determined. In this way, it becomes possible to calculate the electric drive valve opening time or electric drive valve closing time without using future load factors that cannot be known at the time of control.

[0068] Although Figure 11 shows an example where the load factor changes in steps, the same calculation is possible even when it changes continuously, as it will correspond to one of the rows in the table in Figure 10. Also, although Figure 10 shows the switching time against the load factor in a table format, it may also be defined by a function or the like.

[0069] As described above, in the power supply device 50 for the ozone generator according to Embodiment 3, the control unit 13 controls the flow rate of the cooling water by controlling the opening and closing of the electrically driven valve 16 according to predetermined closing and opening times. Compared to Embodiments 1 and 2, the power supply device 50 for the ozone generator according to Embodiment 3 has the advantage of eliminating the need to monitor the air temperature inside the panel and thus eliminating the need for a temperature detector 15.

[0070] In the power supply unit 50 for the ozone generator according to Embodiment 3, the opening and closing control of the electrically driven valve 16 can be performed based on the load factor of the ozone generator 2. The load factor of the ozone generator 2 can be easily determined. Furthermore, since the power supply unit 50 for the ozone generator has a control unit 13, the implementation of the method according to Embodiment 3 into the power supply unit 50 for the ozone generator can be carried out simply and easily. With the power supply unit 50 for the ozone generator according to Embodiment 3, the effect of preventing overheating of the main heating element 12 and preventing condensation of the enclosure 20 can be obtained, similar to Embodiments 1 and 2.

[0071] The configurations shown in the above embodiments are merely examples, and it is possible to combine them with other known technologies, combine different embodiments, and omit or modify parts of the configuration without departing from the gist of the invention. [Explanation of symbols]

[0072] 1 Chiller, 2 Ozone generator, 4 Flow control valve, 5 Cooling water circulation pump, 6 Flow meter, 11 Heat exchanger, 12 Main heating element, 13 Control unit, 14 Fan, 15 Temperature sensor, 16 Electrically driven valve, 17 Heat exchanger mounting plate, 18 Protective panel, 19 Return air passage, 20 Enclosure, 21 Rear panel, 22 Front panel, 26, 27, 30 Space, 28, 31 Virtual plane, 40 Panel, 41, 42 Opening, 44 Enclosure, 50 Power supply for ozone generator, 100 Ozone generator, 121 Transformer, 122 Inverter, 123 Reactor, 300 Processor, 302 Memory, 303 Processing circuit, 304 Interface.

Claims

1. An ozone generator power supply device that supplies power to an ozone generator that generates ozone from an oxygen-containing gas by silent discharge, comprising: a transformer that transforms the voltage from a commercial AC power source; an inverter that converts the AC voltage transformed by the transformer into a higher frequency AC voltage; a reactor connected to the output of the inverter; and a control panel housing that houses at least one of the transformer, the inverter, and the reactor, A heat exchanger is arranged inside or adjacent to the outside of the aforementioned enclosure to cool the air flowing through the inside of the enclosure with cooling water. At least one of the transformer, inverter, and reactor, which is housed inside the enclosure, is cooled by air flowing through the inside of the enclosure. The heat exchanger is connected to an electrically driven valve that controls the flow rate of the cooling water entering and leaving the heat exchanger. The opening and closing of the aforementioned electrically driven valve is controlled by the control unit. A power supply unit for an ozone generator characterized by the following features.

2. The control unit controls the flow rate of the cooling water based on the temperature of the air inside the enclosure, which is the temperature of the air flowing through the inside of the enclosure. The power supply device for an ozone generator according to claim 1, characterized in that it is a power supply device for an ozone generator.

3. The first space, formed above the uppermost end of the main heat-generating portion of the main heat-generating element including the transformer, inverter, and reactor, is designated as the monitoring position for the air temperature inside the panel. The power supply device for an ozone generator according to claim 2, characterized in that it is as described in the previous version.

4. A return air passage is formed for circulating the air inside the panel after the main heat-generating element has been cooled, and in a cross-section viewed from the right or left, The monitoring position for the air temperature inside the panel is a second space within the panel enclosure that is on the return air path side of the first space, which is a vertical first virtual plane that divides the space containing the main heat-generating elements (excluding the return air path) into left and right halves. The power supply device for an ozone generator according to claim 3.

5. The monitoring position for the air temperature inside the panel is a third space within the panel enclosure, which is parallel to the first virtual plane at the position on the return airflow side of the outer casing of the main heating element located at the top of the inside of the panel enclosure, and is on the return airflow side of the second virtual plane that is also on the return airflow side. The power supply device for an ozone generator according to feature 4.

6. A return air passage is formed for circulating the air inside the panel after the main heat-generating elements, including the transformer, inverter, and reactor, have been cooled. The return air passage is designated as the monitoring location for the air temperature inside the control panel. The power supply device for an ozone generator according to claim 2, characterized in that it is as described in the previous version.

7. A temperature detector is installed at the aforementioned monitoring location. A power supply device for an ozone generator according to any one of claims 3 to 6, characterized by the features described herein.

8. The control unit controls the flow rate of the cooling water by controlling the opening and closing of the electrically driven valve based on the temperature sensor's detection value. The power supply device for an ozone generator according to claim 7, characterized in that it is as described in the present invention.

9. The control temperature difference of the air temperature inside the control panel that controls the opening and closing of the electric-driven valve is set to be between 0.3°C and 2°C. The power supply device for an ozone generator according to claim 8, characterized in that it is a power supply device for an ozone generator.

10. The control unit controls the flow rate of the cooling water by controlling the opening and closing of the electrically driven valve according to predetermined closing and opening times. The power supply device for an ozone generator according to claim 1, characterized in that it is a power supply device for an ozone generator.

11. The control unit changes the closing time and the opening time based on the load rate of the ozone generator. The power supply device for an ozone generator according to claim 10.

12. The ozone generator is cooled by a chiller. A portion of the cooling water supplied from the chiller to the ozone generator branches off and flows into and out of the heat exchanger. A power supply device for an ozone generator according to any one of claims 1 to 6, 10, or 11, characterized in that it is the same as the one described above.

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