ELECTRIC POWER RECEIVER AND METHOD FOR CONDENSATION MONITORING IN AN ELECTRIC POWER RECEIVER

Abstract

An electrical power converter (100) comprising a first channel (10) for the inflow of a cooling gas (101), a second channel (20) for the inflow of a cooling fluid (102), at least one first temperature sensing device (14) designed to determine a first gas temperature in the first channel (10), at least one first humidity sensing device (16) designed to determine a first humidity in the first channel (10), at least one second temperature sensing device (24) arranged for determining a second fluid temperature in the second channel (20), and a controller (50) in conjunction with the sensor device. The controller (50) is designed to determine a dew point of the cooling gas (101) based on the determined first gas temperature and first humidity, and to determine a condensation risk based on the determined dew point and second temperature.

Description

AREA OF INVENTION

[0001] The present invention relates generally to electrical power converters, such as frequency converters, inverters and / or rectifiers. In particular, but not exclusively, the present invention relates to condensation monitoring with respect to electrical power converters. GENERAL STATE OF THE ART

[0002] Condensation poses a real threat to electrical power converters, as these products are installed in various demanding environments worldwide. Condensation can cause many unintended defects in the power converter and should therefore be avoided. It can damage the electrical and electronic components of the power converter. This can lead to short circuits, corrosion, premature failure, mold contamination, water leakage from enclosures, or even an electric shock risk for users.

[0003] Users may not always be aware that the environment in which the product is installed could cause condensation. If condensation does cause problems, it is difficult to analyze afterward because the condensed water evaporates after the defect occurs, leaving no trace.

[0004] The products with the greatest risk of condensation are those that use cooling where the main circuit is cooled by a different airflow than the control circuit (typically outside air versus inside air). An example of this is back-channel cooling. This solution creates a large temperature difference between these two environments and could generate condensation on the metal parts and electronic components inside the electrical converter, which is typically warmer than the outside. Another example that could cause condensation is liquid-cooled converters, where parts cooled with cold coolant are exposed to humid air. It is known to control condensation by managing the humidity within the enclosure and / or the device itself.For example, heaters, air conditioners, dehumidifiers, and fans can be used in the vicinity and / or inside the electrical device's enclosure to control the internal temperature and humidity. However, there remains a need to improve electrical power converters with regard to condensation. SUMMARY

[0005] The object of the present invention is to provide an electrical power converter and a method for monitoring condensation in an electrical power converter. A further object of the present invention is that the electrical power converter and the method enable the monitoring of a condensation risk in the electrical power converter when it is used in its operating environment.

[0006] The objectives of the invention are achieved by an electrical power converter and a method for condensation monitoring in an electrical power converter, as defined by the respective main claims.

[0007] According to a first aspect, an electrical power converter is provided. The electrical power converter comprises a first channel for the inflow of a cooling gas, a second channel for the inflow of a cooling fluid, such as a cooling fluid or gas, at least one first temperature measuring device designed to determine a first gas temperature in the first channel, at least one first humidity measuring device designed to determine a first humidity in the first channel, and at least one second temperature measuring device arranged for determining a second fluid temperature in the second channel. The electrical power converter also comprises a control unit connected to the at least one first temperature measuring device, the at least one first humidity measuring device, and the at least one second temperature measuring device.The control system is designed to determine a dew point of the refrigerant gas based on the determined first gas temperature and first humidity, and to determine a condensation risk based on the determined dew point and second temperature.

[0008] Determining the risk of condensation may involve designing the control system to compare the determined dew point and a second temperature that refers to the same time.

[0009] Determining the condensation risk can involve designing the control system to estimate the surface temperature of a surface within the electrical converter based on the second temperature. Preferably, the surface is exposed to the cooling gas as it flows in the first channel. Additionally or alternatively, the surface is fluidically isolated from the second channel, so that the surface is not directly exposed to the cooling fluid flowing in the second channel.

[0010] The electrical converter can include a thermally conductive path between the second channel and the surface, such as via an intermediate structure between the channels, for example, a wall section made of metal or another thermally conductive material. The thermally conductive material can have a thermal conductivity of at least 0.7 W / (m·K) or at least 10 W / (m·K).

[0011] The control system can be designed to determine a period for which the specific condensation risk was higher than a predefined risk threshold and to store that period in a memory.

[0012] The control system can be designed to generate a warning signal if the condensation risk is higher than a predefined acceptable condensation risk.

[0013] The control system can be designed to store the condensation risk in a buffer.

[0014] The control system can be designed to store the specified dew point and / or the second temperature with time information, such as a timestamp or timestamps (preferably synchronized or at least synchronizable with each other, so that the dew point can be compared with the second temperature at corresponding times) in a memory.

[0015] The control system can be designed to store the initial gas temperature and / or humidity along with time-stamped information in a memory. The second channel can be configured to provide return-channel cooling. This may entail at least separate outlets for the first and second channels.

[0016] The electrical power converter preferably comprises a current directional control circuit and a control circuit. The current directional control circuit can be arranged to be cooled by the cooling fluid, and the control circuit can be arranged to be cooled by the cooling gas.

[0017] The current straightening circuit can include at least power semiconductor devices used to provide main current straightening for the electrical converter, and optionally one or more DC link energy storage elements, such as DC capacitors. The current straightening circuit can additionally include driver circuits for switching the power semiconductor devices. Furthermore, the current straightening circuit can additionally include one or more filter components, such as filter inductor(s) and / or filter capacitors.

[0018] The control circuit, on the other hand, can include electronics that provide control over the operation of the electrical converter. For example, the control circuit can include the controller, such as processing unit(s) and storage device(s), designed to process data from sensors, such as current and voltage sensors, as well as temperature and humidity sensors, and to generate control signals and provide them to one or more other devices of the electrical converter, such as the driver circuits.

[0019] In various embodiments, the current directional circuit can be at least partially arranged to be cooled by the cooling fluid in the second channel. For example, one or more heat sinks, arranged to cool components / devices of the current directional circuit, can be exposed to the cooling fluid. The control circuit, on the other hand, can be at least partially arranged to be cooled by the cooling gas in the first channel. Thus, the cooling gas can be applied either directly or via one or more heat sinks of the control circuit to cool its components / devices. Therefore, the cooling performance requirements for components / devices in the second channel may differ from those in the first channel.

[0020] The electrical power converter may include an output, such as a digital output terminal, designed to output a signal representative of the specific condensation risk, with the output arranged to provide a control signal to a heating and / or cooling device.

[0021] According to a second aspect, a method for condensation monitoring in an electrical power converter is provided. The method includes determining, by means of a controller, the dew point of a cooling gas flowing in a first channel of the electrical power converter, determining, by means of a controller, the temperature of a cooling fluid, such as a coolant or a second cooling gas, flowing in a second channel of the electrical power converter, and determining, by means of a controller, a condensation risk based on the determined dew point and the second temperature.

[0022] The procedure may involve comparing the determined dew point and the second temperature, which refer to the same point in time.

[0023] The procedure may include determining a period for which the condensation risk was higher than a predefined risk threshold and storing the period in a memory.

[0024] Determining the condensation risk can involve estimating the surface temperature of a surface within the electrical converter based on the second temperature. Preferably, the surface is exposed to the cooling gas as it flows in the first channel. Additionally or alternatively, the surface can be fluidically isolated from the second channel, so that the surface is not directly exposed to the cooling fluid flowing in the second channel.

[0025] The present invention provides an electrical power converter and a method for monitoring condensation in an electrical power converter. The present invention offers advantages over known solutions by reducing immersion defects caused by condensation and by enabling lower warranty costs through the ability to read the fault memory to detect potential misuse when the product is installed in locations where condensation is possible. The user can be warned of the increased risk of condensation, allowing the user to take measures to mitigate the problem, for example, by reducing the moisture content of the refrigerant.

[0026] Several other advantages will become clear to the expert based on the following detailed description.

[0027] The expression “a number of” can denote any positive integer starting at one (1).

[0028] The expression "a multitude of" can denote any positive integer starting with two (2), that is, at least two, two, at least three, three, and so on. The terms "first" and "second" are used here to distinguish one element from another and not to specifically prioritize or order them, unless explicitly stated otherwise.

[0029] The embodiments of the present invention presented herein are not to be construed as limiting the applicability of the appended claims. The verb "comprise" is used here as an open limitation that does not preclude the presence of features not listed. The features listed in the appended claims are freely combinable with one another, unless expressly stated otherwise.

[0030] The novel features considered to characterize the present invention are set forth in particular in the appended claims. However, the present invention itself, with regard to its structure and function, together with its further aims and advantages, is best understood from the following description of specific embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE FIGURES

[0031] In an exemplary and non-limiting manner, some embodiments of the invention are illustrated in the figures of the accompanying drawings. Fig. Figure 1 schematically illustrates an electrical power converter. Fig. Figure 2 schematically illustrates an electrical power converter. Fig. Figure 3 shows a flowchart of a procedure for condensation monitoring in an electrical power converter. DETAILED DESCRIPTION OF SOME VERSIONS

[0032] Fig. Figure 1 schematically illustrates an electrical power converter 100. The electrical power converter 100 comprises a first channel 10 for the inflow of a cooling gas 101, a second channel 20 for the inflow of a cooling fluid 102, such as a coolant or a second cooling gas, at least one first temperature measuring device 14 designed for determining a first gas temperature in the first channel 10, at least one first humidity measuring device 16 designed for determining a first humidity in the first channel 10, at least one second temperature measuring device 24 arranged for determining a second fluid temperature in the second channel 20, and a control unit 50 in conjunction with the at least one first temperature measuring device 14, the at least one first humidity measuring device 16, and the at least one second temperature measuring device 24.

[0033] If the cooling fluid 102 is a second cooling gas, the second cooling gas can be the same or a different gas than the cooling gas 101. For example, the cooling gas 101 can be air and the second cooling gas 102 can be air or a different gas, or vice versa.

[0034] Fig. Figure 1 shows the cooling gas 101 and the cooling fluid 102, e.g., a coolant or a second cooling gas, in a parallel flow arrangement; however, they could also be arranged in a counterflow arrangement. Furthermore, the cooling gas 101 can flow from bottom to top as shown in Figure 1. Fig. 1 or flow from top to bottom. The same applies to the cooling fluid 102.

[0035] Determining the risk of condensation may involve the controller 50 being designed to compare the determined dew point and the second temperature relating to the same time.

[0036] For example, determining the condensation risk may involve the controller 50 being designed to estimate a surface temperature of a surface 30 in the electrical converter 100 based on the second temperature.

[0037] Surface 30 is preferably fluidically isolated from the second channel. Thus, surface 30 is not directly exposed to the cooling fluid flowing in the second channel.

[0038] The electrical converter can include a thermally conductive path between the second channel and the surface 30, such as via an intermediate structure between the channels, for example, a wall section made of metal and / or another thermally conductive material. The thermally conductive material or set of materials can have a thermal conductivity of at least 0.7 W / (m·K) or preferably at least 10 W / (m·K).

[0039] The estimate can be based on a heat transfer model that uses the second temperature as an input parameter and for which the controller 50 or another processing unit is set up. The model can thus include a correction factor that can model the temperature of, for example, a metal part or parts, or a wall between the first and second temperatures, where condensation is most likely to occur.

[0040] The model can also include other parameters relating to the heat transfer between a second surface exposed to the cooling fluid and surface 30 exposed to the cooling gas. Preferably, surface 30 is exposed to the cooling gas 101 flowing in the first channel 10. Comparing the dew point with the estimated surface temperature of surface 30 provides information about possible condensation on surface 30, for example, about times when condensation is likely or certain to occur. Alternatively, the estimation can simply be such that the controller 50 is designed to assume the surface temperature is equal to or a predefined number of degrees lower than the second temperature, such as in the range of 0.1 to 5.0 degrees Celsius or even up to 10 degrees Celsius.

[0041] The controller 50 can be configured to determine a period during which the condensation risk exceeded a predefined risk threshold and to store this period in memory. The period can be continuous or the sum of shorter periods and can optionally influence the specific condensation risk. The predefined risk threshold can be selected based on the embodiment. In various embodiments, the condensation risk can have a value in the range of zero to one, where the values ​​can be zero, one, or any value in between. Alternatively, the condensation risk can have only one of two values: zero or one. Thus, the choice of the predefined risk threshold can also be influenced by how the condensation risk is determined.For example, in a simple case, the risk may be zero if the dew point is lower than the second temperature or the estimated surface temperature, and one if the dew point is equal to or higher than the second temperature or the estimated surface temperature.

[0042] The controller 50 can be configured to generate a warning signal if the condensation risk exceeds a predefined acceptable condensation risk. The predefined acceptable condensation risk can be equal to the predefined risk threshold. Alternatively, the predefined acceptable condensation risk can differ from the predefined risk threshold, for example, it can be lower than it.

[0043] The warning signal can, for example, include three stages: green (low risk level; no dew point detected), yellow (medium risk level; warning that the converter device is near the dew point), and red (high risk level; the dew point has been reached). The electrical converter 100 can be designed to count the number of yellow and red detections and also to sum the time for each stage. This information could be used to identify how frequently and for how long the electrical converter 100 has been exposed to conditions that could reduce its lifespan. This could, for example, affect maintenance or warranty claims.

[0044] Furthermore, yellow and red states can also be used to trigger a heating and / or cooling device, such as a heating element and / or a fan, in conjunction with the electrical power converter 100, which may be located, for example, on the rear of the electrical power converter 100. For example, a yellow state can activate the fan at low speed and a red state can activate the fan at high speed to prevent dew and moisture from condensing on the internal electronics and mechanical parts of the electrical power converter 100 and causing a reduced service life due to damage. Naturally, the invention is not limited to a specific number of stages but can include any number of stages.

[0045] Dew detection can be part of a condition-based monitoring system, which consists of capturing a baseline stored in the electrical power converter 100 or in a cloud storage system, later comparing the actual data with the baseline during use, and detecting any times when the dew point and / or condensation risk threshold has been exceeded.

[0046] In some embodiments, in addition to comparing the second temperature or the estimated surface temperature with the dew point at specific points in time, the duration during which the second temperature or the estimated surface temperature was continuously equal to or lower than the dew point can also be configured to influence the determination of the condensation risk. Short periods of such a condition may therefore not increase the risk as much as a longer period with the condition persisting continuously.

[0047] The controller 50 can preferably be designed to store the specific condensation risk in a memory. This allows historical condensation risk data to be easily analyzed.

[0048] The controller 50 can be designed to store the determined dew point and / or the second temperature along with time information in a memory. This information can subsequently be used to re-determine the condensation risk in other ways and / or for diagnostic purposes, for example, in connection with the operation of the sensors or the like.

[0049] The controller 50 can additionally or alternatively be designed to store the initial gas temperature and / or humidity along with time information in a memory. This allows the dew point to be subsequently determined and / or analyzed, or used for diagnostic purposes.

[0050] Fig. Figure 1 further illustrates that the electrical converter 100 can comprise a current directional circuit 22 and a control circuit 12. The current directional circuit 22 can be arranged to be cooled by the cooling fluid 102, and the control circuit 12 can be arranged to be cooled by the cooling gas 101. The electrical converter 100 may or may not include a cabinet 105 containing the current directional circuit 22 and the control circuit 12.

[0051] In some embodiments, the electrical converter 100 may include an output (not shown), for example, a digital output terminal, designed to output a signal representative of the specific condensation risk, the output being arranged to provide a control signal to a heating and / or cooling device (not shown). The heating and / or cooling device may be located in the cabinet 105 of the electrical converter 100 or in conjunction with the inlet of the first channel 10 and / or the second channel 20 of the electrical converter 100. Alternatively, the heating and / or cooling device may be located in the same space as the electrical converter 100, regardless of whether a cabinet 105 is present. In this way, the heating and / or cooling device can be selectively used only or mostly when the condensation risk is high, in order to reduce it or prevent it from increasing.

[0052] Optionally, a base 110 can also be arranged on or in conjunction with the electrical power converter 100. Alternatively, the electrical power converter 100 can be mounted on a support structure, for example on a rear wall 150, or directly on the rear wall 150.

[0053] Fig. Figure 1 also illustrates the rear wall 150, near or against which the electrical converter 100 can be arranged. Channels can be provided in the rear wall 150 to which the second channel 20 of the electrical converter 100 can be connected, allowing the cooling fluid 102 to flow through the rear wall 150 and into the second channel 20, thus enabling back-channel cooling.

[0054] In some embodiments, an inlet of the second channel 20 can be located in the same space as an inlet of the first channel 10, but an outlet of the second channel 20 is connected to the channel of the rear wall 150 or another support structure. This allows the heated cooling fluid 102 to be removed from the space in which the electrical power converter 100 is installed.

[0055] Fig. Figure 2 schematically illustrates an electrical power converter 100 in a perspective view. Fig. Figure 2 shows the flow of cooling gas 101, such as air, and cooling fluid 102, such as water or air, through the corresponding inlets and outlets. Fig. Figure 3 shows a flowchart of a procedure for a method for condensation monitoring in an electrical power converter 100.

[0056] Point or process stop 300 refers to an optional start phase of the process. It may include setting up the electrical power converter 100 to be operational.

[0057] The point or process stop 310 refers to the determination, for example by a control 50, of a dew point of a cooling gas 101 flowing in a first channel 10 of the electrical converter 100.

[0058] The point or process stop 320 refers to the determination, for example by the control 50, of a temperature of a cooling fluid 102 flowing in a second channel 20 of the electrical converter 100.

[0059] Point or procedure stop 330 refers to determining, for example by control 50, a condensation risk based on the determined dew point and the second temperature. The procedure may involve comparing the determined dew point and the second temperature with each other, referring to the same point in time.

[0060] The determination of the condensation risk may also include estimating a surface temperature of a surface 30 in the electrical power converter 100 based on the second temperature.

[0061] Optionally, the procedure can include determining a period for which the condensation risk was higher than a predefined risk threshold and storing the period in a memory.

[0062] In some embodiments, the method may include outputting a signal representative of the specific condensation risk for controlling a heating and / or cooling device.

[0063] The procedure can be stopped at point or procedure step 399.

Claims

[1] Electrical power converter (100), comprising: a first channel (10) for the inflow of a cooling gas (101), a second channel (20) for the inflow of a cooling fluid (102), such as a coolant or a second cooling gas, at least one first temperature determining device (14) designed to determine a first gas temperature in the first channel (10), at least one first humidity determining device (16) designed to determine a first humidity in the first channel (10), at least a second temperature determination device (24) arranged for determining a second fluid temperature in the second channel (20), and a controller (50) in conjunction with 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), wherein the controller (50) is designed to: Determining a dew point of the refrigerant gas (101) based on the determined initial gas temperature and initial humidity, and Determining a condensation risk based on the determined dew point and the second temperature. [2] Electrical power converter (100) according to claim 1, wherein the determination of the condensation risk includes the control being designed to compare the determined dew point and the second temperature relating to the same time. [3] Electrical converter (100) according to claim 1 or 2, wherein the determination of the condensation risk includes the control being designed to estimate a surface temperature of a surface (30) in the electrical converter based on the second temperature. [4] Electrical converter (100) according to claim 3, wherein the surface (30) is exposed to the cooling gas when it flows in the first channel. [5] Electrical power converter (100) according to claim 3 or 4, wherein the surface (30) is fluidically insulated from the second channel. [6] Electrical power converter (100) according to one of claims 3-5, comprising a thermally conductive path between the second channel and the surface (30). [7] Electrical power converter (100) according to one of claims 1-6, wherein the control is designed to determine a period of time for which the condensation risk was higher than a predefined risk threshold and to store the period of time in a memory. [8] Electrical power converter (100) according to one of claims 1-7, wherein the control is designed to generate a warning signal when the condensation risk is higher than a predefined acceptable condensation risk. [9] Electrical power converter (100) according to one of claims 1-8, wherein the control is designed to store the condensation risk in a storage device. [10] Electrical power converter (100) according to one of claims 1-9, wherein the control is designed to store the determined dew point and / or the second temperature with time information in a memory. [11] Electrical converter (100) according to one of claims 1-10, wherein the control is designed to store the determined first gas temperature and / or the first humidity with time information in a memory. [12] Electrical power converter (100) according to one of claims 1-11, wherein the second channel is arranged to provide return channel cooling. [13] Electrical power converter (100) according to one of claims 1-12, comprising a current directional circuit and a control circuit, wherein the current directional circuit is arranged to be cooled by the cooling fluid and the control circuit is arranged to be cooled by the cooling gas. [14] Electrical power converter (100) according to any one of claims 1-13, comprising an output designed to output a signal representative of the specific condensation risk, wherein the output is arranged to provide a control signal to a heating and / or cooling device. [15] Method for monitoring condensation in an electrical power converter, the method comprising: Determine, by means of a control (50), a dew point of a cooling gas flowing in a first channel of the electrical converter, Determine, by control (50), a temperature of a cooling fluid, such as a liquid or a gas, flowing in a second channel of the electrical converter, and Determine, by control (50), a condensation risk based on the determined dew point and the second temperature. [16] Method according to claim 15, comprising determining a period for which the condensation risk was higher than a predefined risk threshold and storing the period in a memory. [17] Method according to claim 15 or 16, wherein the determination of the condensation risk includes estimating a surface temperature of a surface (30) in the electrical power converter based on the second temperature. [18] Method according to any one of claims 15-17, comprising comparing the determined dew point and the second temperature with each other, relating to the same time. [19] Method according to any one of claims 15-18, comprising outputting a signal representative of the determined condensation risk for controlling a heating and / or cooling device.