Power converter and method for condensation monitoring in power converter
By incorporating cooling gas and fluid channels and monitoring devices into the power converter, the threat of condensation to the power converter is resolved, enabling effective condensation risk monitoring and prevention, and reducing equipment defects and warranty costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DANFOSS DRIVES AS
- Filing Date
- 2025-11-24
- Publication Date
- 2026-05-22
AI Technical Summary
Condensation poses a threat to power converters, potentially damaging electrical and electronic components, and current technologies struggle to effectively monitor and prevent condensation risks.
By setting first and second channels in the power converter for cooling gas and fluid flow respectively, and equipped with temperature and humidity determination devices, the controller monitors dew point and temperature comparisons to determine condensation risk and generate alarms or control heating/cooling devices to reduce condensation.
Effective monitoring and prevention of condensation reduces equipment defects, lowers warranty costs, and provides condensation risk warnings so users can take action to reduce the damage of condensation to power converters.
Smart Images
Figure CN122072249A_ABST
Abstract
Description
Technical Field
[0001] This invention generally relates to power converters (e.g., frequency converters, inverters, and / or rectifiers). Specifically (however, but not limited to), this invention relates to condensation monitoring for power converters. Background Technology
[0002] Because power converters are installed in a variety of harsh environments worldwide, condensation poses a real threat. Condensation can cause numerous unforeseen defects in the converter and should therefore be avoided. Condensation can damage the electrical and electronic components of the converter. Risks may include short circuits, corrosion, premature failure, mold contamination, water leakage from the casing, and even electric shock to the user.
[0003] Users may not always realize that the environment where the product is installed can cause condensation. Furthermore, if condensation causes problems, it is difficult to analyze afterwards because the condensate evaporates after the defect occurs, so it may not leave any trace.
[0004] Products with the highest risk of condensation are those using cooling methods that employ different airflows (typically outdoor and indoor air) to cool the main circuitry compared to the control circuitry. One example is known as back-channel cooling. This solution results in a significant temperature difference between the two environments and can potentially cause condensation on metal components and electronic parts inside the power converter, which are generally warmer than the outside. Another example that can lead to condensation is liquid-cooled converters where components cooled by cold coolant are exposed to humid air.
[0005] It is well known that condensation can be controlled by regulating the humidity of the air inside the enclosure and / or the device itself. For example, heaters, air conditioners, dehumidifiers, and fans can be used around and / or inside the enclosure of electronic devices to control the temperature and humidity inside the enclosure. However, improvements are still needed for cold energy to power converters. Summary of the Invention
[0006] One object of the present invention is to provide a power converter and a method for monitoring condensation in the power converter. Another object of the present invention is that the power converter and method are capable of monitoring the risk of condensation in the power converter during its use within the operating environment of the power converter.
[0007] The object of the present invention is achieved by a power converter as defined in the respective independent claims and a method for condensation monitoring in the power converter.
[0008] According to a first aspect, a power converter is provided. The power converter includes: a first channel for cooling gas flow; a second channel for cooling fluid (e.g., coolant or gas) flow; at least one first temperature determining device configured to determine a first gas temperature in the first channel; at least one first humidity determining device configured to determine a first humidity in the first channel; and at least one second temperature determining device arranged to determine a second fluid temperature in the second channel. The power converter also includes a controller connected to the at least one first temperature determining device, the at least one first humidity determining device, and the at least one second temperature determining device. The controller is configured to determine a dew point of the cooling gas based on the determined first gas temperature and the first humidity, and to determine a condensation risk based on the determined dew point and the second temperature.
[0009] Determining the risk of condensation may include: the controller being configured to compare the determined dew point and second temperature associated with the same time instance with each other.
[0010] Determining the risk of condensation may include configuring the controller to estimate the surface temperature of a surface in the power converter based on a second temperature. Preferably, this surface is acted upon by cooling gas as it flows in the first channel. Alternatively or additionally, the surface is fluidly isolated relative to the second channel, so that the surface is not directly acted upon by the cooling fluid flowing in the second channel.
[0011] The power converter may include a heat conduction path between the second channel and the surface, for example, via an intermediate structure between the channels (e.g., a wall portion made of metal or other thermally conductive material). The thermally conductive material may have a thermal conductivity of at least 0.7 W / (m·K) or at least 10 W / (m·K).
[0012] The controller can be configured to determine the time period during which the determined condensation risk is higher than a predefined risk threshold and store that time period in memory.
[0013] The controller can be configured to generate an alarm signal if the condensation risk is higher than a predefined acceptable condensation risk.
[0014] The controller can be configured to store condensation risks in memory.
[0015] The controller can be configured to store the determined dew point and / or second temperature, along with time instance information (e.g., one or more timestamps), in a memory (preferably synchronized or at least synchronized with each other, so that the dew point can be compared with the second temperature at the corresponding time instance).
[0016] The controller can be configured to store the determined first gas temperature and / or first humidity, as well as time instance information, into a memory.
[0017] The second channel can be arranged to provide back channel cooling. This can mean that there are at least independent outlets for the first and second channels.
[0018] The power converter preferably includes a power conversion circuit and a control circuit. The power conversion circuit may be arranged to be cooled by a cooling fluid, and the control circuit may be configured to be cooled by a cooling gas.
[0019] The power conversion circuit may include at least the power semiconductor devices used for the main power conversion of the power converter, and optionally include DC link energy storage elements (e.g., DC capacitors). The power conversion circuit may additionally include driver circuitry for switching the power semiconductor devices. Furthermore, the power conversion circuit may additionally include one or more filter components (e.g., filter inductors and / or filter capacitors).
[0020] On the other hand, the control circuit may include electronic components for providing control over the operation of the power converter. For example, the control circuit may include a controller (e.g., including a processing unit and a storage device) configured to process data from sensors (e.g., current sensors, voltage sensors, and temperature and humidity sensors), and generate control signals and provide the control signals to one or more other devices (e.g., driver circuitry) of the power converter.
[0021] In various embodiments, the power conversion circuit may be at least partially arranged to be cooled by a cooling fluid in the second channel. For example, one or more heat sinks arranged to cool the components / devices of the power conversion circuit may be subjected to the cooling fluid. On the other hand, the control circuit may be at least partially arranged to be cooled by a cooling gas in the first channel. Thus, the cooling gas may be arranged directly or via one or more heat sinks of the control circuit to cool the components / devices of the control circuit. Therefore, the cooling capacity requirements for the components / devices in the second channel may differ compared to those in the first channel.
[0022] The power converter may include an output (e.g., a digital output port) configured to output a signal representing a determined risk of condensation, wherein the output is arranged to provide control signals to heating and / or cooling devices.
[0023] According to a second aspect, a method for condensation monitoring in a power converter is provided. The method includes: determining, by a controller, the dew point of a cooling gas flowing in a first channel of the power converter; determining, by the controller, the temperature of a cooling fluid (e.g., a coolant or a second cooling gas) flowing in a second channel of the power converter; and determining a condensation risk by the controller based on the determined dew point and the second temperature.
[0024] The method may include comparing the determined dew point and second temperature associated with the same time instance with each other.
[0025] The method may include: determining a time period in which the condensation risk is higher than a predefined risk threshold, and storing that time period in a memory.
[0026] Determining the risk of condensation may include estimating the surface temperature of a surface in the power converter based on a second temperature. Preferably, this surface is acted upon by cooling gas as it flows in the first channel. Alternatively, the surface may be fluidly isolated relative to the second channel, so that the surface is not directly acted upon by the cooling fluid flowing in the second channel.
[0027] This invention provides a power converter and a method for monitoring condensation in the power converter. Compared to known solutions, this invention offers the following advantages: it reduces dive defects due to condensation, and if the product is installed in a location where condensation may occur, it can reduce warranty costs by reading fault memory to detect potential misuse. Users can receive warnings of increased condensation risk, and as a result, users can take measures (e.g., by reducing the humidity in the cooling gas) to mitigate the problem.
[0028] Based on the following detailed description, various other advantages will become apparent to those skilled in the art.
[0029] The expression “several” in this text may refer to any positive integer starting from one (1).
[0030] The expression “multiple” can refer to any positive integer starting from two (2), that is, at least two, two, at least three, three, and so on.
[0031] Unless otherwise expressly stated, the terms “first” and “second” as used herein are used to distinguish one element from another and do not specifically prioritize or order them.
[0032] The exemplary embodiments of the invention presented herein should not be construed as limiting the applicability of the appended claims. The verb "comprising" as used herein is an open-ended limitation and does not exclude the presence of unmentioned features. Unless otherwise expressly stated, the features mentioned in the appended claims may be freely combined with each other.
[0033] Novel features considered characteristic of the invention are set forth in particular in the appended claims. However, the structure, operation, and additional objects and advantages of the invention itself will be better understood when the following description of specific embodiments is read in conjunction with the accompanying drawings. Attached Figure Description
[0034] Some embodiments of the invention are shown in the accompanying drawings by way of example and not limitation.
[0035] Figure 1 A power converter is illustrated schematically.
[0036] Figure 2 A power converter is illustrated schematically.
[0037] Figure 3 A flowchart illustrating a method for monitoring condensation in a power converter is shown. Detailed Implementation
[0038] Figure 1 A power converter 100 is schematically shown. The power converter 100 includes a first channel 10 for the flow of cooling gas 101, a second channel 20 for the flow of cooling fluid 102 (e.g., coolant or second cooling gas), at least one first temperature determining device 14 configured to determine a first gas temperature in the first channel 10, at least one first humidity determining device 16 configured to determine a first humidity in the first channel 10, at least one second temperature determining device 24 arranged to determine a second fluid temperature in the second channel 20, and a controller 50 connected to at least one first temperature determining device 14, at least one first humidity determining device 16 and at least one second temperature determining device 24.
[0039] When the cooling fluid 102 is a second cooling gas, the second cooling gas may be the same as or different from the cooling gas 101. For example, the cooling gas 101 may be air, and the second cooling gas 102 may be air or some other gas, or vice versa.
[0040] Figure 1 The cooling gas 101 and cooling fluid 102 (e.g., coolant or second cooling gas) are shown arranged in a co-current flow configuration; however, they can alternatively be arranged in a counter-current flow configuration. Furthermore, the cooling gas 101 can be arranged as follows: Figure 1Flowing from bottom to top, or from top to bottom. This also applies to cooling fluid 102.
[0041] Determining the risk of condensation may include: the controller 50 being configured to compare the determined dew point and second temperature associated with the same time instance with each other.
[0042] For example, determining the risk of condensation may include: the controller 50 being configured to estimate the surface temperature of the surface 30 in the power converter 100 based on a second temperature.
[0043] Preferably, surface 30 is fluid-isolated from the second channel. Therefore, surface 30 is not directly affected by the cooling fluid flowing within the second channel.
[0044] The power converter may include a heat conduction path between the second channel and the surface 30, for example, via an intermediate structure between the channels (e.g., a wall portion made of metal and / or other thermally conductive material). The thermally conductive material or material assembly may have a thermal conductivity of at least 0.7 W / (m·K) (more preferably, at least 10 W / (m·K)).
[0045] The estimation can be based on a heat transfer model that takes a second temperature as an input parameter, and the controller 50 or other processing unit is arranged to run that heat transfer model. Therefore, the model can include a correction factor that can simulate, for example, the temperature of one or more metal components or walls between the first and second channels where condensation is most likely to occur.
[0046] The model may also include additional parameters related to heat transfer between the second surface acted upon by the cooling fluid and the surface 30 acted upon by the cooling gas. Therefore, preferably, surface 30 is acted upon by the cooling gas 101 flowing in the first channel 10. Comparing the dew point with the estimated surface temperature of surface 30 provides information related to the condensation that may occur on surface 30 (e.g., related to the time at which condensation may or will occur). Alternatively, the estimation can be simple, with controller 50 configured to assume the surface temperature is equal to or below the second temperature by a predefined degree (e.g., in the range of 0.1 to 5.0 degrees Celsius, or even up to 10 degrees Celsius).
[0047] The controller 50 can be configured to determine and store in memory a time period during which the condensation risk is higher than a predefined risk threshold. This time period can be continuous or a sum of shorter time periods, and it can optionally influence the determined condensation risk. The predefined risk threshold can be selected based on the implementation. In various implementations, the condensation risk can have a value in the range of zero to one (it can have values of zero and one, or any value between both). On the other hand, the condensation risk can have only one of two values (zero or one). Therefore, the selection of the predefined risk threshold may also be influenced by how the condensation risk is determined. For example, in a simple case, the risk can be zero if the dew point is below a second temperature or the estimated surface temperature, and the risk is one if the dew point is equal to or higher than the second temperature or the estimated surface temperature.
[0048] Controller 50 can be configured to generate an alarm signal if the condensation risk is higher than a predefined acceptable condensation risk. The predefined acceptable condensation risk can be equal to a predefined risk threshold. Alternatively, the predefined acceptable condensation risk can be different from the predefined risk threshold (e.g., lower than the predefined risk threshold).
[0049] For example, alarm signals can include three levels: green (low risk level; dew point not detected), yellow (medium risk level; warning that the converter device is approaching the dew point), and red (high risk level; dew point has been reached). The power converter 100 can be configured to count the number of yellow and red detections and also summarize the time for each level. This can be used to identify the frequency and duration of the power converter 100's exposure to operating conditions that may shorten its lifespan. For example, this could affect maintenance or warranty.
[0050] Furthermore, yellow and red operating conditions can also be used to trigger heating and / or cooling devices (e.g., including heating elements and / or fans) connected to the power converter 100 (e.g., located on the back side of the power converter 100). For example, a yellow operating condition may cause the fan to activate at a low speed, and a red operating condition may cause the fan to activate at a high speed to prevent condensation and moisture on the internal electronic and mechanical components of the power converter 100 and to avoid shortened lifespan due to damage. Of course, the invention is not limited to a specific number of levels and can have any number of levels.
[0051] Dew detection can be part of condition-based monitoring, which involves acquiring a baseline stored in the power converter 100 or cloud storage system, then comparing the actual data during use to the baseline, and detecting any time instances that exceed the dew point and / or condensation risk threshold.
[0052] In some embodiments, in addition to comparing the second temperature or estimated surface temperature with the dew point on a time-by-time basis, the amount of time during which the second temperature or estimated surface temperature remains equal to or below the dew point can also be configured to influence the determination of condensation risk. Therefore, short periods of such operating conditions may not increase the risk as much as long periods of continuous operation with said conditions.
[0053] Preferably, the controller 50 can be configured to store the determined condensation risk in a memory. Therefore, historical data on condensation risk can be easily analyzed.
[0054] The controller 50 can be configured to store the determined dew point and / or second temperature, along with time instance information, into a memory. This information can then be used to reassess the condensation risk in different ways and / or for diagnostic purposes (e.g., in relation to sensor operation).
[0055] Alternatively, controller 50 can be configured to store the determined first gas temperature and / or first humidity, along with time instance information, in a memory. Therefore, the dew point can subsequently be re-determined and / or analyzed, or used for diagnostic purposes.
[0056] Figure 1 The power converter 100 is also shown to include a power conversion circuit 22 and a control circuit 12. The power conversion circuit 22 may be arranged to be cooled by a cooling fluid 102, and the control circuit 12 may be arranged to be cooled by a cooling gas 101. The power converter 100 may or may not include a cabinet 105 that houses the power conversion circuit 22 and the control circuit 12.
[0057] In some embodiments, the power converter 100 may include an output (not shown) (e.g., a digital output port) configured to output a signal representing a determined condensation risk, wherein the output is arranged to provide control signals to a heating and / or cooling device (not shown). The heating and / or cooling device may be located within a cabinet 105 of the power converter 100 or connected to the inlet of a first channel 10 and / or a second channel 20 of the power converter 100. Alternatively, the heating and / or cooling device may be located in the same room as the power converter 100, regardless of the presence of a cabinet 105. Therefore, the heating and / or cooling device may be selectively used only or primarily when the condensation risk is high, to reduce the condensation risk or prevent an increase in the condensation risk.
[0058] Optionally, the base 110 may be disposed on or connected to the power converter 100. Alternatively, the power converter 100 may be attached to a support structure (e.g., a support structure on the rear wall 150) or directly attached to the rear wall 150.
[0059] Figure 1 A rear wall 150 is also shown, and the power converter 100 may be arranged close to or against the rear wall 150. A second channel 20 of the power converter 100 may be present in the rear wall 150 to which a channel is connected to allow cooling fluid 102 to flow through the rear wall 150 and into the second channel 20, thus enabling back channel cooling.
[0060] In some embodiments, the inlet of the second channel 20 may be in the same space as the inlet of the first channel 10; however, the outlet of the second channel 20 is connected to a channel or other support structure in the rear wall 150. Therefore, the heated cooling fluid 102 can be removed from the space where the power converter 100 is installed.
[0061] Figure 2 The power converter 100 is schematically shown in perspective view. Figure 2 The flow of cooling gas 101 (e.g., air) and cooling fluid 102 (e.g., water or air) through corresponding inlets and outlets is shown.
[0062] Figure 3 A flowchart of a method for monitoring condensation in a power converter 100 is shown.
[0063] Project or method step 300 refers to an optional initiation phase of the method. It may include setting the power converter 100 to be operationally ready.
[0064] Project or method step 310 refers to determining (e.g., by controller 50) the dew point of the cooling gas 101 flowing in the first channel 10 of the power converter 100.
[0065] Project or method step 320 refers to determining (e.g., by controller 50) the temperature of the cooling fluid 102 flowing in the second channel 20 of the power converter 100.
[0066] Project or method step 330 refers to determining (e.g., via controller 50) the risk of condensation based on the determined dew point and second temperature. The method may include comparing the determined dew point and second temperature with respect to the same time instance.
[0067] The determination of condensation risk may also include estimating the surface temperature of surface 30 in power converter 100 based on a second temperature estimate.
[0068] Optionally, the method may include: determining a time period during which the condensation risk is higher than a predefined risk threshold, and storing that time period in a memory.
[0069] In some embodiments, the method may include: outputting a signal representing the determined risk of condensation for controlling the heating and / or cooling devices.
[0070] This method can stop at step 399 of the project or method.
Claims
1. A power converter (100), comprising: The first channel (10) is used for the flow of cooling gas (101). The second channel (20) is used for the flow of cooling fluid (102), such as coolant or a second cooling gas. At least one first temperature determining device (14) is configured to determine the first gas temperature in the first channel (10). At least one first humidity determining device (16) is configured to determine a first humidity in the first channel (10). At least one second temperature determining device (24) is arranged to determine the temperature of the second fluid in the second channel (20), and A controller (50) is connected to the at least one first temperature determining device (14), the at least one first humidity determining device (16), and the at least one second temperature determining device (24), and the controller (50) is configured to: The dew point of the cooling gas (101) is determined based on the determined first gas temperature and first humidity, and The risk of condensation is determined based on the established dew point and second temperature.
2. The power converter (100) according to claim 1, wherein, The determination of the condensation risk includes: the controller being configured to compare the determined dew point and the second temperature with respect to the same time instance.
3. The power converter (100) according to claim 1 or 2, wherein, The determination of the condensation risk includes: the controller being configured to estimate the surface temperature of the surface (30) in the power converter based on the second temperature.
4. The power converter (100) according to claim 3, wherein, The surface (30) is acted upon by the cooling gas as the cooling gas flows in the first channel.
5. The power converter (100) according to claim 3 or 4, wherein, The surface (30) is fluid isolated relative to the second channel.
6. The power converter (100) according to any one of claims 3-5, comprising: The heat conduction path between the second channel and the surface (30).
7. The power converter (100) according to any one of claims 1-6, wherein, The controller is configured to: determine the time period during which the condensation risk is higher than a predefined risk threshold, and store the time period in a memory.
8. The power converter (100) according to any one of claims 1-7, wherein, The controller is configured to generate an alarm signal if the condensation risk is higher than a predefined acceptable condensation risk.
9. The power converter (100) according to any one of claims 1-8, wherein, The controller is configured to store the condensation risk in a memory.
10. The power converter (100) according to any one of claims 1-9, wherein, The controller is configured to store the determined dew point and / or the second temperature and time instance information into a memory.
11. The power converter (100) according to any one of claims 1-10, wherein, The controller is configured to store the determined first gas temperature and / or first humidity and time instance information into a memory.
12. The power converter (100) according to any one of claims 1-11, wherein, The second channel is configured to provide back channel cooling.
13. The power converter (100) according to any one of claims 1-12, comprising: A power conversion circuit and a control circuit, wherein the power conversion circuit is arranged to be cooled by the cooling fluid, and the control circuit is arranged to be cooled by the cooling gas.
14. The power converter (100) according to any one of claims 1-13, comprising: An output terminal configured to output a signal representing the determined risk of condensation, wherein the output terminal is arranged to provide a control signal to a heating device and / or a cooling device.
15. A method for monitoring condensation in a power converter, the method comprising: The dew point of the cooling gas flowing in the first channel of the power converter is determined by the controller (50). The controller (50) determines the temperature of the cooling fluid, such as liquid or gas, flowing in the second channel of the power converter, and The controller (50) determines the condensation risk based on the determined dew point and second temperature.
16. The method of claim 15, comprising: The time period during which the condensation risk exceeds a predefined risk threshold is determined and stored in a memory.
17. The method according to claim 15 or 16, wherein, The determination of the condensation risk includes estimating the surface temperature of the surface (30) in the power converter based on the second temperature.
18. The method according to any one of claims 15-17, comprising: The determined dew point and the second temperature, which are associated with instances of the same time, are compared with each other.
19. The method according to any one of claims 15-18, comprising: The output signal represents the determined risk of condensation, which can be used to control the heating and / or cooling devices.