Hybrid cooling for power electronics units

Abstract

The present invention relates to hybrid cooling for power electronics units, and in particular, provides a power electronics unit, a vapor compression system incorporating the power electronics unit, and a method of cooling the power electronics unit. The power electronics unit includes a semiconductor portion and an inductor portion. About 80% of the heat generated by the power electronics unit can be sourced from the semiconductor portion. About 20% of the heat generated by the power electronics unit can be sourced from the inductor portion. The semiconductor portion is cooled using at least one fan. The inductor portion is cooled using a working fluid (e.g., refrigerant). The working fluid can be provided in the vapor compression system upstream of an evaporator. Limiting use of the working fluid to only cooling the inductor portion of the power electronics unit can minimize the impact of the power electronics unit on the vapor compression system.

Description

[0001] Cross-reference to related applications This application claims the benefit of U.S. Provisional Application No. 62 / 704328, filed on May 5, 2020, the contents of which are hereby incorporated in their entirety. Background Technology

[0002] Refrigerated trucks and trailers are commonly used to transport perishable goods, such as agricultural products, meat, poultry, fish, dairy products, cut flowers, and other fresh or frozen perishable products. To preserve perishable goods, a transport refrigeration unit (TRU) is typically mounted to the truck or trailer. The transport refrigeration unit includes a compressor for circulating refrigerant within the unit. The compressor can be mechanically driven (e.g., using a direct mechanical coupling or belt drive) or electrically driven. When mechanically driven, the compressor is powered by the vehicle's engine. When electrically driven, the compressor can be powered by a generator or onboard battery.

[0003] The compressor's duty cycle can vary depending on various factors, such as ambient temperature, the type and volume of cargo, the desired temperature of the cargo space, and the frequency and duration of opening the cargo space for loading or unloading. For most of its operating time, the compressor may operate at less than full load and may occasionally be completely shut off. Therefore, for efficiency purposes, it is common to provide a control system for varying the compressor's operation (e.g., speed). One way to control the compressor's operation is by using a power electronics unit. For example, a power electronics unit can be used to selectively vary the power supplied to the compressor (e.g., by varying the current, voltage, and / or frequency). Accordingly, the power electronics unit, when included, can be a critical component for transport refrigeration units.

[0004] If not properly cooled, the power electronics unit may overheat, potentially damaging the circuitry within the unit (e.g., causing it to malfunction) and / or leading to product safety issues (e.g., due to heat generation). Liquid cooling has been explored to prevent or at least mitigate potential overheating of the power electronics unit. For example, in the vapor compression cycle of a transport refrigeration unit, previous transport refrigeration units have included a power electronics unit, in which the entire power electronics unit is cooled by passing the refrigerant through it (e.g., in series with a compressor). However, using refrigerant from the transport refrigeration unit to cool the entire power electronics unit may affect the transport refrigeration unit's ability to provide efficient cooling for perishable goods, as the added heat source (i.e., the power electronics unit) increases the cooling load.

[0005] Therefore, there remains a need for methods to cool power electronics units with more efficient systems and methods that minimize the impact on the source of the fluid used for cooling (e.g., transport refrigeration units). Summary of the Invention

[0006] According to one embodiment, a vapor compression system is provided, including a compressor, an evaporator, and a power electronics unit. The compressor includes an electrically driven motor for increasing the pressure of a working fluid. The evaporator is in fluid communication with the compressor. The evaporator is configured to transfer heat from an external medium to the working fluid. The power electronics unit controls the transfer of electrical power to the electrically driven motor. The power electronics unit includes a semiconductor portion and an inductor portion. The semiconductor portion includes at least one fan configured to transfer heat from the semiconductor portion. The inductor portion includes at least one conduit configured to receive at least a portion of the working fluid. The working fluid is configured to transfer heat from the inductor portion.

[0007] According to additional or alternative embodiments, the inductor portion receives at least a portion of the working fluid from upstream of the evaporator.

[0008] According to additional or alternative embodiments, working fluid from the inductor section is transferred to the compressor.

[0009] According to additional or alternative embodiments, working fluid from the inductor section is transferred to the evaporator.

[0010] According to additional or alternative embodiments, the heat generated by the power electronics unit is proportional to the electrical power transferred to the electric drive motor.

[0011] According to additional or alternative embodiments, at least 60% of the heat generated by the power electronics unit originates from the semiconductor portion.

[0012] According to additional or alternative embodiments, less than 40% of the heat generated by the power electronics unit originates from the inductor portion.

[0013] According to additional or alternative embodiments, the at least one fan transfers substantially all of the heat originating from the semiconductor portion.

[0014] According to additional or alternative embodiments, the working fluid transfers substantially all of the heat originating from the inductor portion.

[0015] According to additional or alternative embodiments, the working fluid is a refrigerant.

[0016] According to another aspect of this disclosure, a power electronic device unit is provided, comprising a semiconductor portion and an inductor portion. The semiconductor portion includes at least one fan configured to transfer heat from the semiconductor portion. The inductor portion includes at least one conduit configured to receive a working fluid. The working fluid is configured to transfer heat from the inductor portion.

[0017] According to additional or alternative embodiments, at least 60% of the heat generated by the power electronics unit originates from the semiconductor portion.

[0018] According to additional or alternative embodiments, less than 40% of the heat generated by the power electronics unit originates from the inductor portion.

[0019] According to additional or alternative embodiments, the at least one fan transfers substantially all of the heat originating from the semiconductor portion.

[0020] According to additional or alternative embodiments, the working fluid transfers substantially all of the heat originating from the inductor portion.

[0021] According to another aspect of this disclosure, a method for cooling a power electronic device unit is provided. The power electronic device unit includes a semiconductor portion with at least one fan and an inductor portion with at least one conduit. The method includes the step of passing a working fluid through the conduit. The working fluid transfers heat from the inductor portion. The method also includes the step of operating at least one fan to transfer heat from the semiconductor portion.

[0022] According to additional or alternative embodiments, the method further includes transferring electrical power from the power electronics unit to an electrically driven motor of the compressor, the compression mechanism creating pressure for changing the working fluid.

[0023] According to additional or alternative embodiments, the heat generated by the power electronics unit is proportional to the electrical power transferred to the electric drive motor.

[0024] According to additional or alternative embodiments, at least 60% of the heat generated by the power electronics unit originates from the semiconductor portion, and substantially all of the heat originating from the semiconductor is transferred by the at least one fan.

[0025] According to additional or alternative embodiments, less than 40% of the heat generated by the power electronics unit originates from the inductor portion, and substantially all of the heat originating from the inductor portion is transferred by the working fluid. Attached Figure Description

[0026] The subject matter of this disclosure is particularly pointed out and clearly claimed in the claims at the end of the specification. The following description of the drawings should not be considered limiting in any way. Referring to the drawings, similar elements are similarly numbered: Figure 1 This is a schematic diagram of a vapor compression system according to one aspect of the present disclosure, which includes a compressor, a condenser, an evaporator, and an expansion valve, wherein a power electronics unit receives working fluid from upstream of the evaporator, and the working fluid from the power electronics unit is transferred to the compressor.

[0027] Figure 2 This is a schematic diagram of a vapor compression system according to one aspect of the present disclosure, which includes a compressor, a condenser, an evaporator and an expansion valve, wherein a power electronics unit receives working fluid from upstream of the evaporator and the working fluid from the power electronics unit is transferred to the evaporator.

[0028] Figure 3 This is a perspective view of a power electronic device unit with semiconductor and inductor portions according to one aspect of this disclosure. Figure 1 and Figure 2 As shown in the image.

[0029] Figure 4 This is a flowchart illustrating a method for cooling a power electronic device unit according to one aspect of the present disclosure. Detailed Implementation

[0030] Vapor compression systems (e.g., incorporated into a transport refrigeration unit) typically include a compressor, condenser, expansion valve, and evaporator. Refrigerant circulates through the vapor compression system to cool a medium (e.g., air in the cargo compartment of a truck / trailer). The refrigerant exits the compressor through the discharge port at high pressure and high enthalpy. The refrigerant then flows through the condenser at high pressure, releasing heat to an external fluid medium (e.g., an air or water source). The refrigerant then flows through an expansion valve that expands it to a low pressure. After expansion, the refrigerant flows through the evaporator and absorbs heat from another medium (e.g., air). The refrigerant then re-enters the compressor through the suction port, completing the cycle.

[0031] To increase or decrease cooling, the operation (e.g., speed) of the compressor can be adjusted. For example, to increase cooling, the refrigerant can circulate within the vapor compression system at an increased rate, and conversely, to decrease cooling, the refrigerant can circulate at a slower rate. To control the operation of the compressor, a power electronics unit can be utilized. It should be understood that the power electronics unit can be any electronic device / system capable of varying the speed of the compressor. The power electronics unit may include multiple components, each of which may require a different amount of cooling. For example, a particular component may generate more heat and therefore may require a greater degree of cooling. In some instances, at least a portion of the power electronics unit is cooled using at least a portion of the refrigerant from the vapor compression system (e.g., the transport refrigeration unit). To reduce the impact on the source of the refrigerant, a hybrid cooling system is provided. A hybrid cooling system is a system that combines both forced air cooling and liquid cooling.

[0032] Now referring to the attached diagram, in Figure 1 A schematic diagram of a vapor compression system 100 is shown, including a compressor 110, a condenser 150, an evaporator 120, and an expansion valve 140, wherein a power electronics unit 130 receives working fluid upstream of the evaporator 120. It should be understood that the working fluid can be any fluid capable of transferring heat (e.g., water, refrigerant, brine, etc.). It is contemplated that the driving force of the working fluid through the power electronics unit 130 may be from the compressor 110 of the vapor compression system 100 (e.g., where no additional compressor or pump separate from the existing compressor 110 of the vapor compression system 100 is required). The compressor 110 includes an electrically driven motor 111 for increasing the pressure of the working fluid. It is contemplated that the electrically driven motor 111 may be an AC or DC motor that can be mounted to the compressor 110. The evaporator 120 is in fluid communication with the compressor 110. Being in fluid communication can be interpreted as meaning that the evaporator 120 and the compressor 110 are included within the same vapor compression system 100 (e.g., where the working fluid passing through the evaporator 120 also passes through the compressor 110). Evaporator 120 is configured to transfer heat from an external medium (e.g., an air source or a water source) to the working fluid.

[0033] Power electronics unit 130 is used to control (e.g., via one or more wired connections) the electrical power (e.g., from an onboard battery within the transport refrigeration unit) delivered to the electric drive motor 111. Power electronics unit 130 includes a semiconductor portion 132 and an inductor portion 131. Semiconductor portion 132 includes at least one fan 133 configured to transfer heat from semiconductor portion 132. Inductor portion 131 includes at least one conduit 134 configured to receive at least a portion of a working fluid (e.g., from upstream of evaporator 120). The working fluid is used to transfer heat from inductor portion 131.

[0034] Once the working fluid is used by the power electronics unit 130 to remove heat from the inductor section 131, it can be delivered to the compressor 110 (as in...). Figure 1 (as shown in) or fed to evaporator 120 (as in Figure 2 (As shown in the diagram). In some instances, the working fluid can be supplied from the power electronics unit 130 to both the compressor 110 and the evaporator 120. For example, a portion of the working fluid can be supplied from the power electronics unit 130 to the compressor 110, and a portion of the working fluid can be supplied from the power electronics unit 130 to the evaporator 120. It is advantageous to supply the working fluid from the power electronics unit 130 to the evaporator 120 when the heat generated by the inductor portion 131 is not sufficiently high to utilize the full cooling capacity of the working fluid. Conversely, it is advantageous to supply the working fluid from the power electronics unit 130 to the compressor 110 when the heat generated by the inductor portion 131 is sufficiently high to utilize most of the cooling capacity of the working fluid.

[0035] The heat generated by the power electronics unit 130 is proportional to the electrical power transferred to the electric drive motor 111 of the compressor 110. For example, when more electrical power is transferred to the electric drive motor 111, the power electronics unit 130 generates more heat, and when less electrical power is transferred to the electric drive motor 111, the power electronics unit 130 generates less heat. Regardless of the amount of heat generated, the power electronics unit 130 can generate more heat in one part than in another. For example, the semiconductor part 132 can generate more heat than the inductor part 131. In some instances, at least 60% of the heat generated by the power electronics unit 130 originates from the semiconductor part 132. In some instances, less than 40% of the heat generated by the power electronics unit 130 originates from the inductor part 131. To minimize the impact on the vapor compression system (e.g., within a transport refrigeration unit), the semiconductor part 132 can be air-cooled (e.g., using one or more fans 133).

[0036] For example, at least one fan 133 may be used to dissipate substantially all of the heat originating from the semiconductor portion 132. This can be interpreted as meaning that the semiconductor portion 132 cannot be cooled using any cooling capacity of the working fluid. Instead of utilizing the working fluid to cool both the semiconductor portion 132 and the inductor portion 131, the system 100 uses only the working fluid to cool the inductor portion 131. In some instances, the working fluid dissipates substantially all of the heat originating from the inductor portion 131. This can be interpreted as meaning that the inductor portion can be cooled using only the working fluid. However, it should be appreciated that one or more fans 133 may be used to remove at least a portion of the heat generated by the inductor portion 131. For example, the fan 133 for the semiconductor portion 132 may be configured to direct airflow through both the semiconductor portion 132 and the inductor portion 131. However, it is contemplated that the inductor portion 131 may have a separate fan (not shown) dedicated to cooling the inductor portion 131.

[0037] By limiting liquid cooling to only the inductor portion 131, the impact of the power electronics unit 130 on the vapor compression system 100 is minimized (e.g., by at least 60% compared to a process where liquid cooling is applied to the entire power electronics unit 130). Instead of using the working fluid from the vapor compression system 100 to cool the entire power electronics unit 130 as has been done in previous applications, the system 100 utilizes a hybrid cooling technique to provide liquid cooling only to the inductor portion 131. As mentioned above, the inductor portion 131 is responsible for less than 40% of the heat generated by the power electronics unit 130, with the remaining amount of heat (e.g., at least 60%) attributable to the semiconductor portion 132, which is cooled using at least one fan 133.

[0038] It should be recognized that, due to the shape of the components (e.g., the shape of the semiconductor portion 132), the ability to limit liquid cooling to only the inductor portion 131 is possible. As in Figure 3 As shown, the semiconductor portion 132 can be designed to be relatively flat, which makes it easier to cool the semiconductor portion 132 with air (e.g., using one or more fans 133 disposed near the semiconductor portion 132) than the inductor portion 131 (e.g., which may have a complex three-dimensional structure). To provide liquid cooling to the inductor portion 131, one or more conduits 134 can be used to circulate a working fluid (e.g., refrigerant) around or through the inductor portion 131. As shown, the working fluid cannot flow around or through the semiconductor portion 132 through the conduits 134, and thus no cooling can be provided to the semiconductor portion 132. As described above, this cooling method reduces the influence of the power electronics unit 130 on the source of the working fluid (e.g., the vapor compression system 100).

[0039] exist Figure 4 The diagram illustrates a method 800 for cooling a power electronics unit 130. For example, it can be used... Figure 3 The exemplary power electronic device unit 130 shown and / or... Figure 1 and Figure 2 The exemplary vapor compression system shown accomplishes method 800. As described above, method 800 can be configured for forced air cooling (e.g., using one or more fans 133) of the semiconductor portion 132 of the power electronics unit 130 and liquid cooling (e.g., using one or more pipes 134) of the inductor portion 131 of the power electronics unit 130. Method 800 includes a step 810 for transferring working fluid through the pipes 134 to the inductor portion 131 of the power electronics unit 130 to transfer heat from the inductor portion 131. Method 800 also includes a step 820 for operating at least one fan 133 to transfer heat from the semiconductor portion 132 of the power electronics unit 130. As described above, method 800 can reduce the impact of the power electronics unit 130 on the source of working fluid by at least 60% relative to the process of using liquid cooling for the entire power electronics unit 130.

[0040] Unless otherwise indicated herein or clearly contradicted by the context, the terms “a,” “an,” and “the,” as well as similar references, used in the context of describing the invention are to be construed as encompassing both the singular and plural forms. Unless otherwise claimed, any examples and all exemplary or demonstrative language (e.g., “such as,” “for example,” “like,” etc.) provided herein are intended merely to better illustrate the invention and do not limit its scope. The language in the specification should not be construed as indicating any unclaimed element as essential to the practice of the invention.

[0041] While this disclosure has been described with reference to one or more exemplary embodiments, those skilled in the art will understand that various changes may be made without departing from the scope of this disclosure, and equivalents may be substituted for its elements. Furthermore, many modifications may be made to suit particular situations or materials to the teachings of this disclosure without departing from the basic scope of this disclosure. Therefore, this disclosure is intended to be limited to the specific embodiments disclosed as the best mode contemplated for carrying out this disclosure, but rather to include all embodiments falling within the scope of the claims.

Claims

1. A vapor compression system, comprising: A compressor, which includes an electrically driven motor for increasing the pressure of the working fluid; An evaporator, which is in fluid communication with the compressor, is configured to transfer heat from an external medium to the working fluid; as well as A power electronics unit for controlling the transmission of electrical power to the electric drive motor, the power electronics unit comprising: A semiconductor portion, comprising at least one fan configured to transfer heat from the semiconductor portion; and An inductor portion includes at least one conduit configured to receive at least a portion of the working fluid, the working fluid being configured to transfer heat from the inductor portion. The power electronic device unit uses only the working fluid to cool the inductor portion, so that the semiconductor portion does not use any cooling capacity of the working fluid for cooling.

2. The steam compression system according to claim 1, characterized in that, The inductor section receives at least a portion of the working fluid from upstream of the evaporator.

3. The steam compression system according to claim 2, characterized in that, The working fluid from the inductor section is transferred to the compressor.

4. The vapor compression system according to claim 2, characterized in that, The working fluid from the inductor section is transferred to the evaporator.

5. The vapor compression system according to claim 1, characterized in that, The heat generated by the power electronics unit is proportional to the electrical power transferred to the electric drive motor.

6. The steam compression system according to claim 5, characterized in that, At least 60% of the heat generated by the power electronics unit originates from the semiconductor portion.

7. The steam compression system according to claim 5, characterized in that, Less than 40% of the heat generated by the power electronics unit originates from the inductor portion.

8. The vapor compression system according to claim 6, characterized in that, The at least one fan transfers substantially all of the heat originating from the semiconductor portion.

9. The vapor compression system according to claim 7, characterized in that, The working fluid transfers substantially all of the heat originating from the inductor portion.

10. The vapor compression system according to claim 1, characterized in that, The working fluid is a refrigerant.

11. A power electronic device unit configured to control the operation of an electrically driven motor of a compressor in a vapor compression system of a refrigeration unit, the power electronic device unit comprising: A semiconductor portion, including at least one fan configured to transfer heat from the semiconductor portion; as well as An inductor portion includes at least one conduit configured to receive working fluid from the vapor compression system, the working fluid being configured to transfer heat from the inductor portion. The power electronic device unit uses only the working fluid to cool the inductor portion, so that the semiconductor portion does not use any cooling capacity of the working fluid for cooling.

12. The power electronic device unit according to claim 11, characterized in that, At least 60% of the heat generated by the power electronics unit originates from the semiconductor portion.

13. The power electronic device unit according to claim 11, characterized in that, Less than 40% of the heat generated by the power electronics unit originates from the inductor portion.

14. The power electronic device unit according to claim 12, characterized in that, The at least one fan transfers substantially all of the heat originating from the semiconductor portion.

15. The power electronic device unit according to claim 13, characterized in that, The working fluid transfers substantially all of the heat originating from the inductor portion.

16. A method for cooling a power electronic device unit, the power electronic device unit being configured to control the operation of an electrically driven motor of a compressor in a vapor compression system of a refrigeration unit, the power electronic device unit including a semiconductor portion comprising at least one fan and an inductor portion comprising at least one conduit, the method comprising: The working fluid from the vapor compression system is passed through the pipe, and the working fluid transfers heat from the inductor section; as well as At least one fan is operated to transfer heat from the semiconductor portion. The power electronic device unit uses only the working fluid to cool the inductor portion, so that the semiconductor portion does not use any cooling capacity of the working fluid for cooling.

17. The method for cooling a power electronic device unit according to claim 16, characterized in that, It further includes an electrically driven motor that transfers electrical power from the power electronics unit to the compressor, the compression mechanism causing a change in the pressure of the working fluid.

18. The method for cooling a power electronic device unit according to claim 17, characterized in that, The heat generated by the power electronics unit is proportional to the electrical power transferred to the electric drive motor.

19. The method for cooling a power electronic device unit according to claim 18, characterized in that, At least 60% of the heat generated by the power electronics unit originates from the semiconductor portion, and substantially all of the heat originating from the semiconductor is transferred by the at least one fan.

20. The method for cooling a power electronic device unit according to claim 18, characterized in that, Less than 40% of the heat generated by the power electronics unit originates from the inductor portion, and substantially all of the heat originating from the inductor portion is transferred by the working fluid.

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