Power electronics cooling system and method

Abstract

The present disclosure provides a power electronics cooling system and method. Thermal monitoring and analysis of conditions in a power electronics system includes sensing thermal parameters of interest, such as temperature and humidity, in a housing containing power electronics components. The components are cooled by flowing liquid coolant from a cooler through a cooler plate associated with the power electronics components. Air is circulated through the housing to remove heat from the cooler plate. Based on the sensed parameters, factors such as the relative humidity and dew point of the cooling air can be calculated and evaluated to determine the likelihood of condensation. Alarms, notifications, or recommendations can be output for adjusting the cooler to avoid condensation. The system can also provide an assessment of installation errors and performance degradation over time.

Description

Technical Field

[0001] The present invention relates generally to the field of power electronics and, in particular, to equipment used in industry and cooled by liquid. Background Art

[0002] There are numerous applications for power electronics equipment and systems in industry. Among the most prevalent are various types of motor drives, which include circuitry for driving electromagnetic machines (e.g., single-phase or three-phase motors). The motors driven in many applications can range from fractional horsepower to large, medium, or high voltage devices. Multiple motor drives may be located throughout various parts of a factory or production site. In the case of higher power applications, multi-phase motors are often used with separate motor drives, which may be located in a cabinet generally adjacent to the motor being driven.

[0003] Motor drives and other industrial power devices typically include many circuits that can generate significant amounts of heat during operation. This is particularly true in the case of rectifier circuits, inverter circuits, capacitor banks, and the like. Where possible, these circuits can be cooled by drawing ambient air into and around the circuits or by cooling within the panels and cabinets where the circuits are located and interconnected. However, where circulating air is insufficient to meet component power density, a liquid cooling system can be provided. A liquid cooling system can circulate a cooling liquid (e.g., water with appropriate additives) to absorb heat and discharge it to the environment outside the circuit.

[0004] In liquid-cooled power electronic systems, one problem that may arise is the generation and accumulation of condensation on or around the components and the cooling structures to which the components are mounted. In particular, this condensation may occur when the surface temperature of these components drops below the dew point. It is desirable to eliminate this condensation to avoid damage to the electronic systems and unplanned machine downtime, but existing systems do not truly address this problem effectively. Other potential problems with using liquid-cooled power electronic systems include degradation of the cooling structure over time, initial misconnection of the liquid flow path of the cooling liquid supply, accidental blockage / reduction in flow, accumulation of contaminants, inappropriate coolant type, etc. Currently, there is no effective method available to address these problems. In addition, because the liquid coolant source (e.g., chiller) is typically provided separately from the power electronic equipment, there is little interaction and collaboration during operation to enhance the monitoring and operation of the cooling system or to avoid the slow impact of cooling system problems on the cooling device.

[0005] Additionally, industrial motor drives and other power electronic equipment may be designed with electrical voltage spacing between components and conductors to meet pollution targets or regulations, which are typically categorized by degree. For example, a pollution degree 2 environment is one where only non-conductive pollution typically occurs. It is expected that the temporary conductivity caused by condensation will not be long-lasting enough to cause surface tracking. For example, non-conductive pollution can include normal dust and airborne particles found in an office environment and non-conductive pollution is generally difficult to maintain, depending on both component temperature (and humidity) and the nearby ambient temperature and humidity. Therefore, to avoid unexpected surface tracking failures caused by non-conductive pollution that becomes conductive due to moisture condensation, some users of the device may specify a more demanding (i.e., higher) pollution degree (e.g., more tolerant of higher humidity). However, such devices are generally more expensive due to the design considerations required when condensation occurs. Summary of the Invention

[0006] In a first embodiment, a system includes: a power electronic circuit that, in operation, converts input power from a source into output power suitable for use with a load, the power electronic circuit including a heat extraction component that extracts heat from the power electronic circuit by circulating a liquid coolant flow through the heat extraction component; a housing in which the power electronic circuit is disposed; a fan that, in operation, circulates a flow of ambient air from outside the housing through the interior of the housing to extract heat from the heat extraction component; and a sensor for detecting a parameter of the air flow within the housing. A thermal manager, in operation, processes signals from the sensor and determines a temperature and relative humidity of at least one region of interest within the housing, and generates an output signal representing at least one of the determined relative humidity or a parameter setting of a liquid cooling system providing the liquid coolant flow.

[0007] In another embodiment, a method includes circulating a liquid coolant flow through a heat extraction component of a power electronic circuit, the power electronic circuit being operable to convert input power from a source into output power suitable for use with a load, the power electronic circuit being disposed in an enclosure, directing a flow of ambient air from an exterior of the enclosure to an interior of the enclosure to extract heat from the heat extraction component, and detecting a parameter of the air flow within the interior of the enclosure. The detected parameter is processed to determine a temperature and a relative humidity of at least one region of interest within the enclosure and to generate an output signal representative of at least one of the determined relative humidity or a parameter setting of a liquid cooling system providing the liquid coolant flow.

[0008] In yet another embodiment, a non-transitory computer-readable medium including computer-executable instructions, the computer-executable instructions being configured to, when executed, cause a processor to: process detected parameters of air flow within an enclosure housing power electronics circuitry, the power electronics circuitry converting input power from a source to output power suitable for a load and cooling the enclosure by circulating a liquid coolant flow through a heat extraction component, the air flow being directed from ambient air external to the enclosure to the interior of the enclosure to extract heat from the heat extraction component; the processing determining a temperature and relative humidity of at least one region of interest within the enclosure, and generating an output signal representing at least one of the determined relative humidity or a parameter setting of a liquid cooling system providing the liquid coolant flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] These and other features, aspects, and benefits of the presently disclosed embodiments will become better understood when the following detailed description is read with reference to the accompanying drawings, in which like reference numerals refer to like parts throughout, and in which:

[0010] Figure 1 is a schematic diagram of an exemplary power electronics system (e.g., a motor drive) having a thermal management system that monitors cooling parameters and provides outputs and / or controls based on analysis of the parameters;

[0011] Figure 2 is used for Figure 1 a schematic diagram of an exemplary thermal manager for a system of the type shown;

[0012] Figure 3 is a schematic diagram of another exemplary power electronics system with additional components and sensors for cooling system monitoring and analysis;

[0013] Figure 4 is a block diagram illustrating exemplary logic for performing the various functions performed by the thermal management system of the previous figures;

[0014] Figure 5 is a block diagram illustrating exemplary logic for additional analyses that may be performed by the thermal management system; and

[0015] Figure 6 is a block diagram illustrating exemplary logic for another type of analysis that may be performed by a thermal management system. DETAILED DESCRIPTION

[0016] Presently disclosed embodiments relate to systems and methods for monitoring and analyzing the thermal conditions of liquid-cooled power electronics (e.g., motor drives in industrial applications). The disclosed techniques enable data collection followed by calculations that can identify potential issues such as installation problems, degradation issues, and condensation, unexpected blockages / reductions in flow, contaminant accumulation, and inappropriate coolant type that can affect the performance of system circuits during operation. In some embodiments, these methods provide alerts or notifications to operators who can correct the problem or adjust system settings. In other embodiments, recommendations can be made to operators or even closed-loop control of the refrigeration unit providing the cooling liquid flow can be implemented.

[0017] Furthermore, this technology can be used to assess the likelihood of condensation to comply with pollution degree targets and regulations. That is, users and operators can use a less stringent pollution degree system in which the risk of condensation can be effectively avoided or, at least, the operator can be informed of the risk before it occurs. The benefit of this approach is that the initial and lifetime costs of the system can be reduced compared to the costs of a higher pollution degree system. By way of example, creepage and clearance, as well as insulation, can be defined according to pollution degree levels. In the field, pollution degrees are classified based on the amount of dry pollution and condensation present in the environment. Classification bodies such as Underwriters Laboratories (UL) and the International Electrotechnical Commission (IEC) have established such standards. An example of such classification is provided in US Pat. No. 61010-1, which is incorporated herein by reference. In particular, if power electronics equipment, such as industrial motor drives, could be used that meets the "Pollution Degree 2" standard rather than the "Pollution Degree 3" requirements, costs could be significantly lower.

[0018] Turning now to the accompanying drawings, Figure 1 is a schematic diagram of an exemplary power electronic system 10 comprising, in this case, a motor drive 12. The system is equipped with a thermal management system, generally designated by reference numeral 14, which enables monitoring of the thermal condition and health of the power electronic system.

[0019] like Figure 1 As shown, the system 10 will receive input power from a power source 16, which in most industrial applications is a three-phase AC power source 16 such as a grid or generator, although other power sources may be used. The power electronics and circuitry itself are housed in an enclosure 18 (e.g., a standard NEMA enclosure) or a specialized enclosure (e.g., for an industrial motor control center (MCC)). Such an enclosure is typically provided for physically housing the device, but also allows for use in a controlled internal environment where environmental conditions can be monitored and controlled, as described below. In the case of the power electronics system shown, the input power is transformed and converted into a form suitable for the load (e.g., an electric motor 20).

[0020] In the case of a motor drive 12, input power is applied to a rectifier circuit 22, which converts the AC power into DC power for application to a DC bus 24. As will be appreciated by those skilled in the art, the rectifier circuit can be designed as a passive circuit operating without switch control, or as an active circuit comprising an array of interconnected switches (e.g., IGBTs) controlled to provide a desired DC output. Such a circuit can also allow for useful functions such as regenerative braking. The power on the DC bus is then applied to an inverter circuit 26, where, in the case of a variable-frequency motor drive, the power on the DC bus is converted into controlled-frequency AC output power for the load. Again, as will be appreciated by those skilled in the art, such an inverter circuit can comprise an array of interconnected switches (e.g., IGBTs and bypass diodes) switched in a controlled manner to provide output power at a desired frequency. Generally, therefore, a motor, such as an industrial induction motor, can be driven at a desired speed, which is generally proportional to the output power frequency. Of course, specific control mechanisms can be provided through control of the switches (e.g., torque control, vector control, etc.). A bus circuit 28 can be provided, for example, to improve the regulation of the voltage, current and general operation of the DC bus. Finally, a driver circuit 30 and a control circuit 32 are provided so that the desired switching of the power electronic switches of the inverter circuit can be performed. The control circuit 32 provides a drive signal to the driver circuit based on one or more control schemes that are stored in the memory of the control circuit and are appropriately programmed when the device is debugged (or at any time thereafter). The driver circuit is shown as being communicatively connected to the inverter circuit 26 and optionally connected to the rectifier circuit 22 (for example, when rectification is completed using active control). As will be understood by those skilled in the art, control will typically be completed in a closed-loop manner based on feedback signals from sensors not separately shown in the accompanying drawings. In many possible options, this control allows speed control, starting, stopping, acceleration and deceleration to be synchronized with other devices and downstream processing.

[0021] The component designated by reference numeral 26 in the accompanying drawings represents power electronic switchgear and associated circuitry, which may be referred to as a power structure or power module. In many cases, the power electronic switchgear itself is mounted on a substrate, which in turn is mounted on a cooling plate designated by reference numerals 34 and 36. Such a cooling plate typically comprises a thermally conductive (e.g., metal) structure through which channels are formed to receive a circulating cooling fluid. The plate may include various circuitous pathways for the cooling fluid, as well as internal features to enhance heat transfer. Additionally, the plate may include external features such as fins 38 and 40 that enable heat to be extracted by convection from the interior air of the housing. Due to the currents involved in their operation and the rapid switching under controlled conditions, power electronic switches can generate significant amounts of heat, which is absorbed by the associated cooling plate to improve their operation and extend their service life. However, it should be noted that other components in the power structure (e.g., filter inductors and capacitors, bus capacitors, etc.) may also generate heat during operation. These components may also be cooled in a similar manner, and the performance of their cooling components evaluated as discussed in this disclosure.

[0022] A cooling liquid flow is provided to one or more cooling plates of the system via a coolant cooler 42. In many cases, this device is located outside the electrical enclosure to allow heat to be discharged to the surrounding environment. In the figures, the inflow or supply of cooling liquid is designated by reference numeral 44, while the return flow of liquid heated by circulation through the cooling plates is designated by reference numeral 46. In the illustrated embodiment, the cooling liquid system is closed, so that the liquid is continuously heated and cooled as it removes and then discharges heat generated by the operation of the power electronics. Regulation of the operation of the coolant cooler 42 is provided by a control circuit, generally indicated by reference numeral 48. In general, the coolant cooler and associated controls can be based on any desired refrigeration cycle and generally attempt to maintain a temperature set point for the liquid cooling flow fed to the cooling plates, and various control schemes for such control are contemplated (e.g., conventional on-off set point regulation, PID control, etc.). As discussed below, the set point and other parameters used to control the coolant cooler can be manually input by an operator, or in some cases, can be based on closed-loop control of set points, flow rates, etc., or a hybrid manual / closed-loop control.

[0023] Electronic components that cannot be liquid cooled use forced convection air cooling to remove heat. To facilitate and enhance this transfer, one or more fans 50 are provided at the air inlet 52 of the housing. There may be more than one such inlet, wherein a desired internal duct, channel or defined path (not separately shown) may direct the cooling air flow 54 to the component being cooled. Although not separately shown, one or more outlets or exhaust ports may be provided to allow hot air to escape from the housing. A thermal manager 56 is provided for monitoring and analysis functions of the system, as described more fully below. In the embodiment shown, the component may be provided in the housing along with the power electronics, or in some cases, the component may be provided external to the housing (e.g. Figure 3 In addition, certain instruments are provided in the housing to facilitate monitoring of thermal conditions and operation of cooling components by the thermal manager. Figure 1 In an embodiment, for example, temperature sensors 58, 60, and 62 are provided for monitoring the air temperature at the inlet 52 and on or near the cooling plate or related power structure, and humidity sensors 64, 66, and 68 are provided for monitoring the humidity at the same locations. The temperature and humidity sensors can be of any known type and provide output signals indicative of temperature and humidity, which can be processed to provide actual or representative values ​​for operator information, control, logging, etc.

[0024] In addition, Figure 1 As shown, many components in the housing can be coupled to a network 70, such as a plant communication network, both inside and outside the housing. For example, the motor drive control circuit can exchange data for programming and operation of the motor drive control circuit with a human machine interface (HMI) 72 and a remote control and monitoring system, generally indicated by reference numeral 74. For example, the remote control and monitoring system can include an automation controller, an enterprise monitoring and control system, other motor drives, etc. The same is true for the thermal manager 56, which can provide an indication of the thermal condition to the HMI or other monitoring and control equipment via the network. As described below, in some presently contemplated embodiments, the HMI can allow for the display of notifications, alerts, recommendations, etc., related to the thermal conditions that exist or may exist in the housing as determined by the thermal manager.

[0025] As discussed below, many possible operations are contemplated and can be performed by the thermal manager. For example, depending on the conditions of the ambient air surrounding the enclosure, introducing said ambient air into the enclosure for heat extraction may result in condensation, particularly if the liquid coolant temperature drops below the dew point. Thus, the thermal manager can determine the relative humidity of the cooling air flow within the enclosure, assess the likelihood of condensation, and output a signal to the operator in the form of an alarm or notification, or even provide a recommended temperature setpoint for manual or automatic control of the coolant cooler. Furthermore, the thermal manager can perform assessment functions during initial commissioning of the equipment, for example, to determine whether the piping connections between the coolant cooler and the cooling plate are correctly or incorrectly made. Over time, the thermal manager can also perform monitoring and analysis functions, for example, to determine whether performance degradation may occur suddenly (e.g., due to short-term fouling or blockage of cooling components) or over a longer period of time (e.g., due to slower component fouling, erosion, and corrosion). The thermal manager's monitoring and analysis functions can also be used to ensure compliance with various international pollution degree standards, which categorize the amount of dry contamination and condensation present in the environment.

[0026] Figure 2 Exemplary functional components of the thermal manager 56 are shown. In this example, input interface / signal conditioning circuitry 76 is used to receive data from sensors and any external devices, which may provide configuration programming and data or operational data to the manager. Similarly, output interface / signal conditioning circuitry 78 outputs data based on monitoring and analysis operations performed by the manager. As will be readily understood by those skilled in the art, these interfaces may provide data bus traffic interfaces, data conversion, etc. Processing circuitry 80 is coupled to the interfaces and to memory circuitry 82 and performs any programmed monitoring operations based on programs stored in the memory circuitry, settings stored in the memory circuitry, etc. Any suitable processing circuitry and memory circuitry may be provided, such as a microprocessor, CPU, etc., as well as both volatile memory and non-volatile memory. In operation, the memory circuitry serves as a non-transitory computer-readable medium comprising computer-executable instructions that, when executed, are configured to cause the processor to perform the operations described in the present disclosure. It should also be noted that although the thermal manager 56 discussed in connection with the presently contemplated embodiments may be a stand-alone component, in some other embodiments it may be incorporated into another component (e.g., an automation controller, motor drive, or other automation component) and utilize interface circuitry, processing power, and memory already provided in that component (e.g., provided as an optional product).

[0027] Figure 3 Shown with Figure 1The configuration of system 10 may differ slightly from the configuration of system 10. That is, in some cases, such as in the case of an MCC or system that includes multiple motor drives or motor drives with other electrical components, the power electronics circuitry may be provided in a sub-housing 84 that is itself housed within the larger housing 18. In such cases, the thermal manager may be primarily concerned with the environment within the sub-housing. In some cases, similar or identical thermal manager schemes may be used for multiple sub-housings within the larger housing 18, or even within the larger housing itself. Additionally, in Figure 3 In this embodiment, flow sensors 86 and 88 may be provided to monitor the flow rate of the liquid coolant flow. It should be noted that in some presently contemplated embodiments, such flow sensors may not be used, depending on the functionality sought and the data to be analyzed. Similarly, liquid coolant temperature sensors 90 and 92 may monitor the temperature of the inlet liquid coolant flow, while additional temperature sensors 94 and 96 may monitor the temperature of the outlet or return flow. As described above, in this embodiment, the thermal manager 56 is located external to the housing 18. Further, an access point 98 is provided for wireless communication with a mobile HMI 100, which may be, for example, a thin client HMI, a mobile phone, a tablet, or the like. Such a device may allow an operator to move freely while remaining aware of the thermal conditions in the housing and any possible notifications, alerts, recommendations, etc.

[0028] Figure 3 It is also indicated that other circuits and devices may be present in the housing, and it is contemplated that such devices may also be monitored, if desired, to determine the likelihood of cooling, heating, condensation, etc., as outlined below. In fact, this may be done in certain locations or areas of the housing even where the sensed temperature and humidity are not immediately adjacent to the cooling plate. For example, such devices may include manifolds, inductors, filters, power modules, circuit boards, etc., with or without a cooling plate.

[0029] As described, many different monitoring, analysis, and notification or control operations are implemented by the described system and are presently contemplated. Exemplary logic that may be performed by the system is shown in FIG. Figure 4 、 Figure 5 and Figure 6 In. Figure 4In the logic 102, the humidity and possibility of condensation in the housing or on or near system components are monitored. For example, the logic begins by receiving data, as indicated by operation 104. This can include receiving signals related to the temperature and humidity of the incoming cooling air flow and temperature and humidity signals on or near certain important components (particularly the above-mentioned cooling plates). If desired, signals related to the cooling liquid flow and its temperature can also be received and considered. Where available, the temperatures of other components including the power structure itself can also be received and processed. Such processing can follow the processing outlined in U.S. Patent No. 9,092,030 to Weiss et al., which is hereby incorporated by reference into the present disclosure for all purposes.

[0030] Back to Figure 4 At operation 106, the received signals are processed by the thermal manager to determine the humidity and temperature of the cooling air. This operation may include any signal conversion useful for calculating values ​​representing humidity and temperature, depending on the nature of the sensed and received signals. Then, at operation 108, the humidity and temperature of the air within the enclosed environment of the power structure are determined, which may involve similar signal conversion and calculations. Based on the air conditions thus determined, one or more relative humidity calculations may be performed at operation 110 to derive the specific air conditions at the specific monitored location. As will be understood by those skilled in the art, relative humidity is the ratio of the partial pressure of water vapor in the air to the equilibrium vapor pressure. Generally, this represents the relative saturation of the air. Based on this relative humidity, the dew point of the air can be determined, which indicates the temperature at which condensation will occur. At operation 110, one or more of these parameters are considered, and it should be noted that the actual values ​​of the relative humidity and / or dew point may or may not be calculated based on sensed data. However, it is useful in this logic to be able to compare the relative humidity and / or dew point of the cooling air flow within the enclosure with the temperature of the cooling plate to determine the likelihood of condensation onset. For example, it may be desirable to maintain the liquid coolant stream temperature (and thus the cooling plate temperature) a few degrees above the dew point determined by the relative humidity. Figure 4 These calculations and comparisons are performed at operations 110 and 112 to determine the liquid coolant flow and recommended settings (eg, temperature set points) for the chiller.

[0031] It should be noted that in these operations, references can be made, or system parameters can be set to account for any pollution degree classification of the equipment (e.g., Pollution Degree 2 vs. Pollution Degree 3). Thus, the system can effectively verify compliance with the equipment's pollution degree classification and provide temperature set points, notifications where useful, and alarms to avoid condensation based on the equipment's pollution degree classification.

[0032] It should be noted that actual calculations can be performed on a continuous or periodic basis and as ambient air conditions change (e.g., due to weather changes), calculations and recommendations can take this into account. Similarly, delivery time delays, offsets due to flow or heat transfer through system conduits can certainly be taken into account (e.g., for chiller set point calculations). Additionally, as described above, the system may or may not output actual values ​​for parameters such as relative humidity, dew point, etc., but rather may use values ​​that are operationally valid for the contemplated notification, alarm, monitoring, and control functions.

[0033] At operation 114, the system may determine whether to change the recommendation. In some cases, the system may not know the actual temperature set point of the cooler, but may output a determined recommendation at operation 114 (which may or may not match the actual current set point). Then, at operation 116, an alert or recommendation may be output by the system. In many cases, this may take the form of a visual display element that can be received, interpreted, and displayed on the system HMI. In situations where there is a high likelihood of condensation (e.g., the temperature near the relative humidity indicating component of the cooling air flow is approaching the dew point), then the output may be an actual alert. In some cases, the output may be informational only (e.g., temperature, humidity, dew point, etc.). In addition, as Figure 4 As shown, the system can allow for actual closed-loop control of the chiller settings. In this case, as indicated by operation 118, based on the sensed data and the calculated relative humidity and / or dew point, the thermal manager can output a signal for changing the chiller set point or some other parameter of its operation. The upward arrows in the figure are intended to indicate that these operations are ongoing (i.e., continuously or cyclically) during operation of the system.

[0034] It may be noted that the thermal monitoring and analysis performed by the system may be used for a range of other purposes, some of which may be related to the actual operation of the power electronics system. For example, the analysis may be used as a basis for modifying the switching of power switches (e.g., IGBTs) in the motor drive to limit cycling, reduce temperature excursions, etc. Furthermore, where the system includes more than one cooling plate (or monitoring location), the corresponding relative humidity and / or dew point may be calculated and these relative humidity and / or dew points may be considered together for generating alarms, notifications, recommendations (or control signals), for example to avoid approaching the highest dew point in the monitoring location.

[0035] Figure 51 shows exemplary logic 120 for detecting a connection error between a chiller and a cooling plate. In some cases, during initial installation and commissioning, or during subsequent maintenance or repair, the inlet and outlet conduits may be accidentally reversed, causing cooling fluid to be directed to a port on the cooling plate that is intended to be the outlet of the cooling plate, or vice versa. In some embodiments, optimal or designed operation of the cooling plate may be adversely affected by such an incorrect installation. Figure 5 In the logic of , at operation 122, data is received from temperature sensors that may be associated with the inlet and outlet conduits (specifically in this case) (refer to Figure 3 ). During operation of the electrical component, it can be expected and the thermal manager can be programmed to recognize that the inlet liquid temperature should be lower than the outlet temperature. Then, as indicated under operation 124, a comparison of the inlet temperature and the outlet temperature can be made. Under this step (or in a separate operation), if these values ​​have been calculated, the actual component temperature rise can also be compared with the expected component temperature rise to help evaluate the working order of the cooling system and the electronic component. If it is determined that the outlet temperature is actually lower than the inlet temperature, this can be used as a basis for identifying that the conduit has been reversed. When this condition exists, it will be detected at operation 126 and an alarm or recommendation can be generated and output as indicated under operation 128. As before, this can take the form of a display element of the system HMI or any other interface used during or after initial commissioning.

[0036] Figure 6 Example logic 130 for evaluating changes in the performance of a cooling system over time is shown. As described above, for example, relatively rapid changes may be caused by the introduction or formation of an obstruction in the liquid flow path (e.g., in a cooler, cooling plate, or any interconnecting conduits or components). Over time, degradation may occur due to general system degradation, cooler failure or malfunction, gradual fouling of the cooling plate, erosion or corrosion of the internal structure of the cooling plate, etc. These can be measured by Figure 6logic to detect and alert the controller and operator. In general, the series of operations represented by box 132 can provide the basis for initial and ongoing monitoring and analysis. For example, sensed data is received at operation 134. Of particular interest are specific temperatures at specific locations (e.g., inlet air, at or near the cooling plate, cooling liquid supply and return), as well as associated humidity, and the flow rate of the liquid coolant flow. It should be noted that, as mentioned above, some implementations may not use flow sensors. In this case, the temperature range of the circulating coolant and power electronic components (e.g., IGBTs or nearby structures) can be analyzed as specified in U.S. Patent No. 9,092,030 as described above. At operation 136, values ​​indicating these parameters of interest are calculated, and at operation 138 these values ​​can be stored (e.g., together with a timestamp and any useful operational data that can help assess the system conditions at the time). It can be noted that operation 136 can include calculating the expected temperature increase based on the operation, and this can also be stored for later use in cooling system analysis.

[0037] These same steps may then be performed at a subsequent time, as indicated by operation 140. In practice, this may be done at any useful interval or in an event-driven manner (e.g., when a parameter changes by a specific amount, such as an abnormal increase or decrease in temperature, humidity, or flow rate). Figure 6 The thermal manager may then determine the detected changes by analyzing the changes in operation 142. The thermal manager may be programmed to recognize that some of these noted changes indicate degradation of one or more components or changes in certain characteristics, such as fouling, inefficient cooling of the cooling plate, etc. The thermal manager may then output an alert (or notification), a recommendation (for attention or maintenance), etc., in operation 144. Again, this may take the form of a display component that may be provided on the system HMI or another interface (e.g., a remote system monitoring computer).

[0038] While only certain features of the invention have been illustrated and described herein, numerous modifications and variations will occur to those skilled in the art. It will, therefore, be understood that the appended claims are intended to cover all such modifications and variations as fall within the true spirit of the invention.

Claims

1. A cooling system comprising: a power electronic circuit that, in operation, converts input power from a source into output power suitable for use with a load, the power electronic circuit including a heat extraction component that extracts heat from the power electronic circuit by circulating a stream of liquid coolant through the heat extraction component; a housing in which the power electronic circuit is disposed; a fan that, in operation, circulates a flow of ambient air from outside the housing within the housing to extract heat from the heat extraction component; sensors for detecting parameters of the air flow inside the housing, wherein the sensors include one or more temperature sensors for detecting the temperature of the air flow, one or more humidity sensors for detecting the humidity, and one or more sensors for detecting a signal representing the temperature of the liquid coolant flow; and a thermal manager operable to process signals from the sensor and determine a temperature and a relative humidity of at least one region of interest in the enclosure and to generate an output signal representative of at least one of the determined relative humidity or a parameter setting of a liquid cooling system providing a liquid coolant flow, wherein the thermal manager compares the relative humidity of the air flow with the temperature of the liquid coolant flow to determine a temperature set point for the liquid coolant flow, The thermal manager also performs monitoring and analysis functions to ensure compliance with pollution level standards, which are classifications based on the amount of dry pollution and condensation present in the environment, and provides temperature set points based on the pollution level classifications.

2. The system according to claim 1, wherein: The power electronics circuit comprises a motor drive including a rectifier that converts input AC power to DC power on a bus and an inverter that converts the DC power to controlled frequency AC output power to drive the motor, and wherein the heat extraction component comprises a fluid circulation cooling plate associated with a power structure of the inverter.

3. The system according to claim 1, wherein: A signal representing the temperature of the air flow in the region of interest in the housing is detected, and a signal representing the humidity of the air flow in the region of interest in the housing is detected.

4. The system according to claim 1, wherein: The thermal manager determines a relative humidity of an air flow over or near the heat extraction component.

5. The system according to claim 1, wherein: The thermal manager determines recommended settings for the liquid cooling system and outputs the recommended settings for manual or automatic control of the liquid cooling system to prevent condensation.

6. The system according to claim 1, wherein: The thermal manager determines whether condensation is likely to occur based on the determined relative humidity and outputs an operator-perceivable alarm based on this determination.

7. The system according to claim 1, wherein: The thermal manager determines an error in connections made to a liquid cooling system.

8. The system according to claim 1, wherein: The thermal manager determines degradation of the heat extraction component or the liquid cooling system over time and, based thereon, generates an output perceptible to an operator.

9. A cooling method comprising: circulating a flow of liquid coolant through heat extraction components of a power electronics circuit that, in operation, converts input power from a source into output power suitable for a load, the power electronics circuit being disposed in the housing; directing a flow of ambient air from an exterior of the housing to an interior of the housing to extract heat from the heat extraction component; detecting parameters of an air flow within the housing, wherein the detected parameters include one or more temperatures of the air flow, one or more signals indicative of humidity, and one or more signals indicative of a temperature of the liquid coolant flow; as well as processing the detected parameters to determine a temperature and a relative humidity of at least one region of interest in the housing and generating an output signal representative of at least one of the determined relative humidity or a parameter setting of a liquid cooling system providing the liquid coolant flow, wherein processing the detected parameters includes comparing the relative humidity of the air flow with the temperature of the liquid coolant flow to determine a temperature set point for the liquid coolant flow, Monitoring and analysis functions are performed to ensure compliance with pollution level standards, which are classifications based on the amount of dry pollution and condensation present in the environment, and to provide temperature set points based on the pollution level classifications.

10. The method according to claim 9, comprising: The relative humidity of the air flow over or near the heat extraction component is determined.

11. The method according to claim 9, comprising: Recommended settings for the liquid cooling system are determined and output for use in manually or automatically controlling the liquid cooling system.

12. The method according to claim 9, comprising: Based on the determined relative humidity, it is determined whether condensation is likely to occur, and based on this, an operator-perceivable alarm is output.

13. The method according to claim 9, comprising: Identify errors in the connections made to the liquid cooling system.

14. The method according to claim 9, comprising: Degradation of the heat extraction component or the liquid cooling system over time is determined, and an operator-perceivable output is generated based thereon.

15. A non-transitory computer-readable medium comprising computer-executable instructions that, when executed, are configured to cause a processor to: processing detected parameters of air flow inside an enclosure housing power electronic circuitry that converts input power from a source into output power suitable for a load and is cooled by circulating a liquid coolant flow through a heat extraction component, the air flow being directed from ambient air from an exterior of the enclosure to an interior of the enclosure to extract heat from the heat extraction component, wherein The sensed parameters include one or more temperatures of the air streams, one or more signals indicative of humidity, and one or more signals indicative of the temperature of the liquid coolant stream; wherein the processing determines a temperature and a relative humidity of at least one region of interest in the housing and generates an output signal representative of at least one of the determined relative humidity or a parameter setting of a liquid cooling system providing the liquid coolant flow, wherein the processing includes comparing the relative humidity of the air flow with the temperature of the liquid coolant flow to determine a temperature set point for the liquid coolant flow, The processing further includes performing monitoring and analysis functions to ensure compliance with pollution level standards as classifications based on the amount of dry pollution and condensation present in the environment, and providing temperature set points based on the pollution level classifications.

16. The non-transitory computer readable medium of claim 15, wherein: The processing includes determining recommended settings for the liquid cooling system and outputting the recommendations for use in manually or automatically controlling the liquid cooling system.

17. The non-transitory computer readable medium of claim 15, wherein: The process includes determining whether condensation is likely to occur based on the determined relative humidity, and outputting an operator-perceivable alarm based on this determination.

18. The non-transitory computer readable medium of claim 15, wherein: The processing includes determining an error in connections made to the liquid cooling system or degradation of the heat extraction component or the liquid cooling system over time and generating an operator-perceivable output based thereon, or comparing an inlet liquid coolant temperature and a heat extraction component temperature to determine whether component degradation has occurred.

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