Cooling device for electrically driven vehicle

Abstract

To suppress noise during cooling while suppressing deterioration of cooling capacity to the extent possible.SOLUTION: When at least one of a first condition that set compressor rotational frequency is equal to or lower than limitation compressor rotational frequency preset on the basis of a predetermined noise regulation value and a second condition that set fan rotational frequency is equal to or lower than limitation fan rotational frequency preset on the basis of the predetermined noise regulation value is not satisfied, a cooling device 1 sets corrected compressor rotational frequency and sets corrected fan rotational frequency on the basis of the corrected compressor rotational frequency so that noise when a compressor 3 and a fan 41 are operated is the predetermined noise regulation value or smaller. The cooling device 1 sets the corrected fan rotational frequency to a smaller value as the corrected compressor rotational frequency is higher.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The technology disclosed herein belongs to the technical field relating to cooling devices for electric drive vehicles. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in cooling devices mounted on vehicles, efforts have been made to reduce noise generated when cooling a refrigerant.

[0003] For example, Patent Document 1 discloses a cooling fan control device that sets a refrigerant pressure reference fan rotation speed based on the current refrigerant pressure of the air conditioning system, sets an upper guard rotation speed of the fan corresponding to the required air outlet temperature, and sets the fan rotation speed to the upper guard rotation speed if the vehicle is currently stopped, the current engine rotation speed is the idle rotation speed, and the refrigerant pressure reference fan rotation speed is greater than the upper guard rotation speed, and sets the fan rotation speed to the refrigerant pressure reference fan rotation speed in other cases. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-196364 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the noise increases as the rotation speed of the pressurizer and the rotation speed of the fan increase. The rotation speed of the pressurizer and the rotation speed of the fan are basically set higher as the cooling capacity required increases. Situations in which high cooling capacity is required from the cooling device include a situation in which the battery is quickly charged while the vehicle is stopped, and a situation in which the vehicle is traveling under high load, such as climbing or towing. Therefore, in such situations, the noise increases. In particular, when the vehicle is an electrically driven vehicle that runs using a drive motor as the main driving source, no engine sound is generated, so that even when the vehicle is traveling, the noise generated from the cooling device may be annoying not only to people around the vehicle but also to the vehicle occupants.

[0006] In the cooling fan control device described in Patent Document 1, it is expected that noise can be suppressed by lowering the fan rotation speed to the upper guard rotation speed, but the cooling capacity is reduced. Therefore, there is room for improvement in achieving both high cooling capacity and noise suppression.

[0007] The technology disclosed herein has been made in consideration of the above points, and its purpose is to suppress noise during cooling while minimizing the decrease in cooling capacity as much as possible. [Means for solving the problem]

[0008] In order to solve the above problems, a first aspect of the technology disclosed herein is directed to a cooling device for an electrically driven vehicle that uses a refrigerant to cool electrically driven parts mounted on the vehicle, and includes a pressurizer that pressurizes the refrigerant, a fan that draws outside air into a condenser that cools and condenses the refrigerant pressurized by the pressurizer, an electrically driven part temperature detection unit that detects the temperature of the electrically driven parts, a refrigerant pressure detection unit that detects the pressure of the refrigerant compressed by the pressurizer, and a controller that controls the pressurizer and the fan, the controller calculates a required cooling capacity based on at least a detection result of the electrically driven part temperature detection unit, calculates a set pressurizer rotation speed that is the rotation speed of the pressurizer based on the required cooling capacity, calculates a set fan rotation speed that is the rotation speed of the fan based on the detection result of the refrigerant pressure detection unit, and adjusts the set pressurizer rotation speed to a predetermined noise level. When both a first condition that the set fan rotation speed is equal to or less than a limited pressurizer rotation speed preset based on a regulation value, and a second condition that the set fan rotation speed is equal to or less than a limited fan rotation speed preset based on the specified noise regulation value are satisfied, the pressurizer and the fan are operated at the set pressurizer rotation speed and the set fan rotation speed, respectively, while when at least one of the first condition and the second condition is not satisfied, a corrected pressurizer rotation speed is set and a corrected fan rotation speed is set based on the corrected pressurizer rotation speed so that the noise when the pressurizer and the fan are operated is equal to or less than the specified noise regulation value, and the pressurizer and the fan are operated at the corrected pressurizer rotation speed and the corrected fan rotation speed, respectively, and the higher the corrected pressurizer rotation speed, the lower the corrected fan rotation speed is set.

[0009] That is, when the fan speed is set based on the refrigerant pressure, the higher the compressor speed, the higher the fan speed is set. Therefore, when high cooling capacity is required under normal control, the noise level is likely to exceed the noise regulation value. Therefore, when the noise level is likely to exceed the noise regulation value, the fan speed is set based on the compressor speed, not the refrigerant pressure. In particular, the fan speed is set to be lower as the compressor speed increases.

[0010] The cooling capacity increases as the rotation speed of the pressurizer and the rotation speed of the fan increase. Therefore, by increasing one of the rotation speed of the pressurizer and the rotation speed of the fan and decreasing the other, it is possible to suppress the decrease in cooling capacity. This makes it possible to set a combination of the corrected pressurizer rotation speed and the corrected fan rotation speed that suppresses the decrease in cooling capacity as much as possible while keeping the noise level below the noise regulation value. As a result, the noise level during cooling is suppressed while suppressing the decrease in cooling capacity as much as possible.

[0011] In a second aspect of the technology disclosed herein, in the first aspect, an outside air temperature detection unit is further provided which detects the outside air temperature, and the controller sets the corrected pressurizer rotation speed and the corrected fan rotation speed, respectively, further taking the outside air temperature into consideration.

[0012] With this configuration, since the outside air temperature corresponds to the temperature of the air taken in by the fan, by taking the outside air temperature into consideration, it is possible to more appropriately set the corrected fan speed to suppress the decrease in cooling capacity as much as possible. This makes it possible to suppress the decrease in cooling capacity more effectively while suppressing noise during cooling.

[0013] In a third aspect of the technology disclosed herein, in the first or second aspect, the controller sets the corrected pressurizer rotation speed and the corrected fan rotation speed so that the generated noise is within the noise regulation value.

[0014] According to this configuration, the corrected pressurizer rotation speed and the corrected fan rotation speed can be set to as high values ​​as possible, so that the deterioration of the cooling capacity can be more effectively prevented and the noise during cooling can be suppressed.

[0015] In a fourth aspect of the technology disclosed herein, in the third aspect, the controller calculates cooling capacities for a plurality of combinations of the pressurizer rotation speed and the fan rotation speed at which the generated noise falls within the noise regulation value, and sets the combination among the combinations whose cooling capacity is closest to the required cooling capacity as the modified pressurizer rotation speed and the modified fan rotation speed, respectively.

[0016] According to this configuration, it is possible to set appropriate corrected pressurizer rotation speed and corrected fan rotation speed within a range where noise can be suppressed, thereby more effectively suppressing a decrease in cooling capacity and suppressing noise during cooling.

[0017] In addition, by selecting a combination of the compressor rotation speed and the fan rotation speed that provides the cooling capacity closest to the required cooling capacity, it is possible to prevent excessive cooling capacity from being exerted, thereby minimizing power consumption.

[0018] In a fifth aspect of the technology disclosed herein, in the fourth aspect, when there are multiple combinations whose cooling capacity is closest to the required cooling capacity, the controller sets the combination among the combinations whose compressor rotation speed is the lowest as the corrected compressor rotation speed and the corrected fan rotation speed, respectively.

[0019] According to this configuration, the rotation speed of the pressurizer can be made as low as possible. Since the amount of refrigerant to be cooled is reduced as the rotation speed of the pressurizer is reduced, the refrigerant can be cooled more efficiently. As a result, the cooling efficiency can be improved.

[0020] In a sixth aspect of the technology disclosed herein, in the third aspect, the controller calculates a first compressor rotation speed candidate whose rotation speed is higher by a certain number than the limited compressor rotation speed and a first fan rotation speed candidate based on the first compressor rotation speed candidate, calculates a second compressor rotation speed candidate whose rotation speed is lower by a certain number than the limited compressor rotation speed and a second fan rotation speed candidate based on the second compressor rotation speed candidate, calculates cooling capacities for each of a combination of the limited compressor rotation speed and the limited fan rotation speed, a combination of the first compressor rotation speed candidate and the first fan rotation speed candidate, and a combination of the second compressor rotation speed candidate and the second fan rotation speed candidate, and sets the combination whose cooling capacity is closest to the required cooling capacity among the combinations as the modified compressor rotation speed and the modified fan rotation speed, respectively.

[0021] This configuration allows the amount of calculation by the controller to be minimized, which in turn makes it possible to more effectively prevent a decrease in cooling capacity while suppressing noise during cooling, and further reduces power consumption. Effect of the Invention

[0022] As described above, according to the technique disclosed herein, in a cooling device for an electrically driven vehicle, it is possible to suppress noise during cooling while minimizing deterioration in cooling capacity. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a configuration diagram of a vehicle according to the first embodiment. [Diagram 2] FIG. 2 is a configuration diagram of the cooling device. [Diagram 3] FIG. 3 is a block diagram showing a control system of the cooling device. [Figure 4] FIG. 4 is a map showing the relationship between the compressor rotation speed and the fan rotation speed and the cooling capacity when the outside air temperature is relatively low. [Diagram 5]FIG. 5 is a map showing the relationship between the compressor rotation speed and the fan rotation speed and the cooling capacity when the outside air temperature is relatively high. [Figure 6] FIG. 6 is a diagram showing the relationship between noise regulation values ​​and cooling capacity, where the upper diagram shows a noise regulation line in a cooling capacity map, and the lower diagram shows the relationship between the operating point on the noise regulation line and cooling capacity. [Figure 7] FIG. 7 is a flowchart showing the processing operation of the cooling system ECM. [Figure 8] FIG. 8 is a diagram illustrating a method for calculating the corrected compressor rotation speed and the corrected fan rotation speed in the cooling device according to the second embodiment. [Figure 9] FIG. 9 is a part of a flowchart showing a processing operation of the cooling system ECM of the cooling device according to the second embodiment. [Figure 10] FIG. 10 is the remaining part of the flowchart showing the processing operation of the cooling system ECM of the cooling device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Exemplary embodiments will now be described in detail with reference to the drawings.

[0025] (Embodiment 1) <Overall vehicle configuration> 1 shows a vehicle 100 having a cooling device 1 according to the first embodiment. The vehicle 100 is an electrically driven vehicle that can run mainly by a drive motor 102 that rotates by electricity. The vehicle 100 is, for example, an electric vehicle or a hybrid vehicle.

[0026] The vehicle 100 has a drive motor 102. Rotation of the drive motor 102 is transmitted to two wheels located at the front of the four wheels 101 via a shaft. This allows the vehicle 1 to move (run). The drive motor 102 is a motor generator, and operates as a generator when the vehicle 100 is decelerating (regenerating).

[0027] The drive motor 102 is connected to the battery module 70 via an inverter 103 and a converter 104 .

[0028] The battery module 70 is configured by stacking a plurality of rectangular box-shaped battery cells (not shown). The battery module 70 is disposed under the floor panel of the vehicle 100. The battery cells are configured by, for example, lithium ion batteries or nickel metal hydride batteries.

[0029] The inverter 103 converts between DC power and AC power. When the vehicle 100 is running, the inverter 103 converts the DC power supplied via the converter 104 into three-phase AC current with different phases and supplies it to the drive motor 102. When the vehicle 100 is regenerating, the inverter 103 converts the AC power generated by the drive motor 102 into DC power and supplies it to the converter 104.

[0030] When the vehicle 100 is running, the converter 104 steps down the DC power output from the battery module 70 to a drive voltage for the drive motor 102 and supplies the DC power to the inverter 103. When the vehicle 100 is regenerating, the converter 104 steps up the DC power from the inverter 103 and charges the battery module 70.

[0031] The drive motor 102, the inverter 103, the converter 104, and the battery module 70 are examples of electric drive components mounted on the vehicle 100.

[0032] Overall configuration of the cooling device 2 shows a cooling device 1 mounted on a vehicle 100. The cooling device 1 can cool electric drive components. For example, the cooling device 1 can directly cool the battery module 70 by an endothermic reaction that occurs when a liquid refrigerant changes phase to gas. The cooling device 1 can indirectly cool the drive motor 102 by the refrigerant via a coolant cooling mechanism 21, which will be described later. The refrigerant is, for example, an HFO (hydrofluoroolefin) refrigerant, specifically, R1234yf.

[0033] The cooling device 1 has a battery heat exchanger 2 that exchanges heat between a refrigerant and a battery module 70, a compressor 3 that pressurizes the refrigerant flowing out of the battery heat exchanger 2, and a condenser 4 that cools and condenses the refrigerant pressurized by the compressor 3. The cooling device 1 has a coolant cooling mechanism 21 that cools the coolant that cools the drive motor 102, and an air conditioner 22 that is used to air condition the vehicle interior. The cooling device 1 has a main inflow path 11 that is a refrigerant path leading from the condenser 4 to the battery heat exchanger 2, a first branch inflow path 11a that branches from the main inflow path 11 and leads to the coolant cooling mechanism 21, and a second branch inflow path 11b that branches from the main inflow path 11 and leads to the air conditioner 22. The cooling device 1 has a main outflow path 12 which is a refrigerant path from the battery heat exchanger 2 to the compressor 3, a first branch outflow path 12a from a coolant cooling mechanism 21 to the main outflow path 12, and a second branch outflow path 12b from an air conditioner 22 to the main outflow path 12. The cooling device 1 also has an expansion valve 5 provided in the main inflow path 11 to reduce the pressure of the refrigerant condensed in the condenser 4.

[0034] The compressor 3 pressurizes the refrigerant after heat exchange with the battery module 70. The compressor 3 is, for example, a scroll compressor, and the pressure of the refrigerant flowing out can be adjusted by adjusting the rotation speed. Specifically, the pressure of the refrigerant flowing out from the compressor 3 increases as the compressor rotation speed increases. In other words, the amount of refrigerant flowing out from the compressor 3 increases as the compressor rotation speed increases. When the refrigerant is pressurized by the compressor 3, the temperature of the refrigerant increases due to adiabatic compression.

[0035] Condenser 4 is disposed in the front portion of vehicle 100. Fan 41 is provided on the vehicle rear side of condenser 4. When vehicle 100 is traveling, condenser 4 cools the refrigerant by running wind or a combination of running wind and air drawn in by the rotation of fan 41, while when vehicle 100 is stopped, condenser 4 cools the refrigerant by air drawn in by the rotation of fan 41. In condenser 4, the refrigerant condenses and liquefies as the temperature drops without a drop in pressure.

[0036] In the first embodiment, the fan 41 is electrically driven. The fan 41 has a small electric motor (not shown) and rotates by the rotation of the electric motor. The fan 41 draws in more air as the rotation speed increases. Specifically, the air volume of the fan 41 is directly proportional to the rotation speed of the fan.

[0037] A receiver tank 42 is provided downstream of the condenser 4. The receiver tank 42 temporarily stores the refrigerant liquefied by the condenser 4. The receiver tank 42 is connected to the main inflow path 11. When the refrigerant liquefied by the condenser 4 flows into the receiver tank 42, an amount of refrigerant equivalent to the amount of the inflowing refrigerant flows out from the receiver tank 42 to the main inflow path 11.

[0038] The expansion valve 5 reduces the pressure of the refrigerant in the main inflow path 11, and causes the refrigerant to flow into the battery heat exchanger 2. The temperature of the refrigerant that has passed through the expansion valve 5 drops due to adiabatic expansion. In addition, the pressure drop caused by the expansion valve 5 lowers the saturation temperature (corresponding to the boiling point). In addition, the pressure drop caused by the expansion valve 5 slows the flow of the refrigerant in the heat exchanger 2, so that the refrigerant in the heat exchanger 2 exchanges heat evenly with the battery modules 70.

[0039] The expansion valve 5 is also used to adjust the flow rate of the refrigerant flowing into the battery heat exchanger 2. Specifically, the larger the opening of the expansion valve 5, the larger the flow rate of the refrigerant flowing into the battery heat exchanger 2, whereas the smaller the opening of the expansion valve 5, the smaller the flow rate of the refrigerant flowing into the battery heat exchanger 2.

[0040] The coolant cooling mechanism 21 includes an expansion valve and a heat exchanger. The expansion valve is provided in the first branch inlet path 11a.

[0041] The air conditioner 22 includes an expansion valve, a heat exchanger, and a fan. The expansion valve is provided in the second branch inlet passage 11b. The rotation speed of the fan is set based on the target temperature in the vehicle compartment.

[0042] <Cooling device control system> Next, the control system of the cooling device 1 will be described.

[0043] As shown in Fig. 3, the vehicle 100 has a cooling system ECM (Electric Control Module) 80 which is a controller that mainly controls the cooling device 1. The cooling system ECM 80 includes one or more processors 80a having a CPU, and a memory 80b having a ROM and RAM and storing various programs. The memory 80b is, for example, a non-volatile memory. Programs related to the controls executed by the cooling system ECM 80 are stored in the memory 80b. The cooling system ECM 80 is executed by the processor 80a reading the programs stored in the memory 80b.

[0044] The cooling system ECM 80 receives signals from a battery temperature sensor SW1 that detects the temperature of the battery cells, a first refrigerant pressure sensor SW2 that detects the pressure of the refrigerant flowing into the compressor 3, a second refrigerant pressure sensor SW3 that detects the pressure of the refrigerant pressurized by the compressor 3 and before it flows into the condenser 4, an outside air temperature sensor SW4 that detects the outside air temperature, a motor water temperature sensor SW5 that detects the temperature of the cooling water for the drive motor 102, a vehicle interior temperature sensor SW6 that detects the temperature inside the vehicle interior, and an air conditioning control panel SW7 that controls the air conditioning inside the vehicle interior. The cooling system ECM 80 also receives signals from a PCM (Powertrain Control Module) 81, which is a controller that controls the entire power system of the vehicle 100, and a BECM (Battery Energy Control Module) 82, which is a controller that controls the charging and discharging of the battery module 70. The PCM 81 receives a signal from a vehicle speed sensor SW8. Although not shown, the PCM 81 and the BECM 82 each have a processor and a memory.

[0045] The battery temperature sensor SW1 is disposed, for example, near the refrigerant outlet of the battery module 70. The first refrigerant pressure sensor SW2 is disposed in a position upstream of the compressor 3 in the main outflow path 12. The second refrigerant pressure sensor SW3 is disposed in a position downstream of the compressor 3 and upstream of the condenser 4. The outside air temperature sensor SW4 is disposed on the vehicle front side of the condenser 4. The outside air temperature detected by the outside air temperature sensor SW4 corresponds to the temperature of the air drawn in by the fan 41. The motor water temperature sensor SW5 faces the cooling water passage of the drive motor 102. The water temperature detected by the motor water temperature sensor SW5 is considered to be the temperature of the drive motor 102. The air conditioning control panel SW7 is a panel operated by an occupant of the vehicle 100, and is provided with a switch for controlling the air conditioning on and off, a switch for setting the air volume, a switch for setting the target temperature in the vehicle cabin, and the like. Note that a plurality of battery temperature sensors SW1 may be provided, and may be disposed, for example, in the vicinity of the refrigerant outlet of the battery module 70, as well as in the center of the battery module 70 in a plan view. The battery temperature sensor SW1 and the motor water temperature sensor SW5 are examples of an electric drive component temperature detection unit.

[0046] The cooling system ECM 80 controls the fan 41, the compressor 3, the expansion valve 5, the coolant cooling mechanism 21, and the air conditioner 22 based on signals from the sensors SW1 to SW7, a signal from the PCM 81, and a signal from the BECM 82. Specifically, the cooling system ECM 80 obtains information about the vehicle speed from the PCM 81, obtains information about the target temperature of the object to be cooled (the drive motor 102 and the battery module 70) from the BECM 82, and obtains information about the target temperature in the vehicle cabin from the air conditioning control panel SW7. The cooling system ECM 80 compares the detection results of the battery temperature sensor SW1, the motor water temperature sensor SW5, and the vehicle cabin temperature sensor SW6 with each target temperature to calculate the required cooling capacity Qr of the cooling device 1. The cooling system ECM 80 sets the compressor rotation speed based on the required cooling capacity Qr. The cooling system ECM 80 calculates the amount of air to be supplied to the condenser 4 based on the detection result of the second refrigerant pressure sensor SW3, and sets the fan rotation speed based on the calculated air volume. The cooling system ECM 80 rotates the compressor 3 and the fan 41 at their respective set rotation speeds, and adjusts the openings of the expansion valve 5, the expansion valve of the coolant cooling mechanism 21, and the expansion valve of the air conditioner 22 so that the required flow rate of refrigerant flows in. Also, it adjusts the rotation speed of the fan of the air conditioner 22 according to the target temperature in the vehicle cabin. The cooling capacity is, for example, the amount of heat that the refrigerant can absorb per unit time.

[0047] Furthermore, the cooling system ECM 80 calculates the volume of airflow caused by traveling based on information related to the vehicle speed acquired from the PCM 81. The cooling system ECM 80 takes the volume of airflow caused by traveling into consideration when setting the fan rotation speed. Specifically, the cooling system ECM 80 subtracts the volume of air obtained by the traveling wind from the volume to be supplied to the condenser 4, and sets the fan rotation speed so that the remaining volume of air is obtained by the fan 41. When the volume of air to be supplied to the condenser 4 is entirely obtained by the traveling wind, the cooling system ECM 80 may set the fan rotation speed to 0 so that the fan 41 does not rotate.

[0048] <Cooling capacity map> Next, the cooling capacity of the cooling device 1 will be described.

[0049] As described above, the condenser 4 cools the refrigerant by using at least one of the wind generated by running and the air drawn in by the fan 41. In other words, the condenser 4 cools the refrigerant by using the outside air. Therefore, the cooling capacity of the cooling device 1 depends on the outside air temperature.

[0050] Figures 4 and 5 show cooling capacity maps of the cooling device 1. Figure 4 shows a low temperature cooling capacity map 300 when the outside air temperature is relatively low, and Figure 5 shows a high temperature cooling capacity map 400 when the outside air temperature is relatively high. The low temperature and high temperature cooling capacity maps 300, 400 are each stored in the memory 80b. Here, only two cooling capacity maps are illustrated, but in reality, three or more cooling capacity maps for each outside air temperature are stored in the memory 80b.

[0051] In the low-temperature and high-temperature cooling capacity maps 300, 400, the horizontal axis is the compressor rotation speed, and the vertical axis is the fan rotation speed. The regions Z1 to Z8 are regions with similar cooling capacities, with region Z1 having the lowest cooling capacity and region Z8 having the highest cooling capacity, and the closer to region Z8 the regions Z2 to Z7 are, the higher the cooling capacity. The boundaries between the regions Z1 to Z8 are lines of equal cooling capacity. Basically, the higher the compressor rotation speed and the higher the fan rotation speed, the greater the cooling capacity is, so in each of the regions Z1 to Z8, the further to the upper right from the lower boundary line the higher the cooling capacity is.

[0052] Comparing low-temperature cooling capacity map 300 and high-temperature cooling capacity map 400, it can be seen that low-temperature cooling capacity map 300 has a wider region Z8 than high-temperature cooling capacity map 400. This means that the cooling efficiency is higher when the outside air temperature is lower. In other words, the rotation speed of compressor 3 and fan 41 is limited due to restrictions related to abnormal operation such as choking and noise, which will be described later. The fact that the region with high cooling capacity is wider means that high cooling capacity can be achieved even with a limited rotation speed, and it can be said that this means that the cooling efficiency can be increased.

[0053] Noise suppression control Here, when the cooling device 1 is operated, noise is generated. The noise is generated mainly by the operation of the compressor 3 and the fan 41. The noise increases as the compressor rotation speed and the fan rotation speed increase. As described above, the cooling capacity of the cooling device 1 increases as the rotation speeds of the compressor 3 and the fan 41 increase, so attempting to exert high cooling capacity results in increased noise. In other words, there is a trade-off between cooling capacity and noise.

[0054] Situations in which high cooling capacity is required for the cooling device 1 include a situation in which the battery module 70 is rapidly charged while the vehicle 100 is stopped, and a situation in which the vehicle is traveling at a high load such as climbing or towing. Therefore, in such situations, noise becomes loud. In particular, when the vehicle 100 is an electrically driven vehicle that can travel using the drive motor 102 as the main driving source as in the first embodiment, no engine sound is generated, so that even when the vehicle 100 is traveling, the noise generated from the cooling device 1 may be annoying not only to people around the vehicle 100 but also to the occupants of the vehicle 100.

[0055] In contrast, in the past, the limit compressor speed NCL and the limit fan speed NFL were set in advance based on a predetermined noise regulation value, and when at least one of the set compressor speed and the set fan speed, which are the compressor speed and the fan speed set based on the required cooling capacity, was greater than the limit compressor speed NCL and the limit fan speed NFL, the compressor 3 and the fan 41 were operated at the limit compressor speed NCL and the limit fan speed NFL. For example, as shown in the upper diagram of FIG. 6, it is assumed that the combination of the set compressor speed and the set fan speed (hereinafter referred to as the request operating point P0) is located to the upper right of the combination of the limit compressor speed NCL and the limit fan speed NFL (hereinafter referred to as the limit operating point PL). In the past control, the request operating point P0 was corrected to the limit operating point PL, and the compressor 3 and the fan 41 were operated at the limit compressor speed NCL and the limit fan speed NFL.

[0056] However, as shown in the upper diagram of Fig. 6, in the conventional control, the operating point moves from region Z7 to region Z6, and the cooling capacity decreases. If the cooling capacity decreases, the charging efficiency of the battery module 70 decreases, the deterioration of the drive motor 102 increases, and the cooling efficiency of the vehicle interior by the air conditioning decreases.

[0057] Therefore, in the first embodiment, an operating point is calculated where the noise level indicating the loudness of the noise becomes equal to or lower than the noise level of the limit operating point PL (i.e., the noise regulation value) and where the decrease in the cooling capacity can be suppressed. Specifically, when at least one of a first condition that the set compressor speed is equal to or lower than the limit compressor speed NCL and a second condition that the set fan speed is equal to or lower than the limit fan speed NFL is not satisfied, the cooling system ECM 80 executes noise suppression control for setting a corrected compressor speed and setting a corrected fan speed based on the corrected compressor speed so that the noise level becomes equal to or lower than the noise regulation value. In particular, in the noise suppression control, the corrected fan speed becomes lower as the corrected compressor speed becomes higher.

[0058] As described above, the fan speed is basically set based on the detection result of the second refrigerant pressure sensor SW3. Since the detection result (refrigerant pressure) increases as the compressor speed increases, the fan speed is basically set higher as the compressor speed increases. That is, in normal control, a combination of the compressor speed and the fan speed is set within the range from the lower left to the upper right of the cooling capacity map, as shown by the dashed line in the upper diagram of FIG. 6. However, as shown in the upper diagrams of FIGS. 4, 5, and 6, combinations that actually provide the same level of cooling capacity exist outside the range of normal control. For this reason, if the fan speed is set independently of the refrigerant pressure, it is possible to set an operating point that maintains a high cooling capacity while suppressing the noise level.

[0059] In the first embodiment, in particular, the cooling system ECM 80 obtains the cooling capacity when the compressor 3 and the fan 41 are operated at each candidate operating point for a combination of the compressor rotation speed and the fan rotation speed that makes the noise level the noise regulation value (hereinafter referred to as the candidate operating point), selects the candidate operating point whose cooling capacity is closest to the required cooling capacity as the corrected operating point, and sets the compressor rotation speed and the fan rotation speed of the selected corrected operating point as the corrected compressor rotation speed and the corrected fan rotation speed, respectively. If the corrected operating point is selected so that the noise level becomes the noise regulation value, the compressor rotation speed and the fan rotation speed can be set as high as possible. This makes it easier to maintain a high cooling capacity. The candidate operating points and the cooling capacity of each candidate operating point may be calculated by the cooling system ECM 80, or may be stored in advance in the memory 80b for each cooling capacity map in the form of a map 500 described later, and the cooling system ECM 80 may read an appropriate map based on the outside air temperature to calculate the cooling capacity. In addition, "the cooling capacity is closest to the required cooling capacity" includes the case where the cooling capacity is the same as the required cooling capacity, and when there is a candidate operating point whose cooling capacity is the same as the required cooling capacity, that candidate operating point becomes the candidate operating point whose cooling capacity is closest to the required cooling capacity.

[0060] The noise level increases as the compressor rotation speed and the fan rotation speed increase. For this reason, as shown in the upper diagram of FIG. 6, the operating point where the noise level becomes the noise regulation value is located on a straight line (hereinafter referred to as noise regulation line SL) that slopes downward to the right and where the fan rotation speed decreases as the compressor rotation speed increases. This noise regulation line SL is set based on the compressor rotation speed so that the noise level becomes the noise regulation value, not on the refrigerant pressure. In the upper diagram of FIG. 6, the noise regulation line SL is discontinuous between the upper left part and the lower right part, which is mainly due to the operating limit of the compressor 3. The upper limit of the compressor rotation speed is set based on the upper operating pressure of the compressor 3, and the lower limit of the compressor rotation speed is set based on the rotation speed at which abnormal operation such as choking does not occur. The noise regulation line SL is set based on the noise regulation value. For example, if the noise regulation value is 20 decibels, a noise regulation line is set at which the noise level becomes 20 decibels. This noise regulation value can be set arbitrarily.

[0061] The lower diagram in Fig. 6 is a map 500 showing the cooling capacity at the noise regulation line SL. In the map 500, the horizontal axis indicates the position of the operating point, and the vertical axis indicates the cooling capacity. On the horizontal axis, the operating points have lower compressor rotation speeds and higher fan rotation speeds as they move to the left, and the operating points have higher compressor rotation speeds and lower fan rotation speeds as they move to the right. The limited operating point PL, the candidate operating point P1, and the candidate operating point P2 correspond to PL, P1, and P2 in the upper diagram in Fig. 6, respectively.

[0062] As shown in the map 500, on the noise regulation line SL, the cooling capacity at the candidate operating point P1 is the same as the required cooling capacity (Qr in the lower diagram of FIG. 6). Also, on the noise regulation line SL, the cooling capacity at the candidate operating point P2 is the maximum cooling capacity (Qm in the lower diagram of FIG. 6). When there is a candidate operating point at which the cooling capacity is the same as the required cooling capacity, the cooling system ECM 80 sets the candidate operating point as the corrected operating point. Here, the cooling system ECM 80 sets the candidate operating point P1 as the corrected operating point, and sets the compressor rotation speed and the fan rotation speed of the candidate operating point P1 as the corrected compressor rotation speed and the corrected fan rotation speed, respectively. This is because, although the candidate operating point P2 has a higher cooling capacity, selecting an operating point at which the cooling capacity is equal to or greater than the required cooling capacity may deteriorate the cooling efficiency.

[0063] When the required cooling capacity is greater than the maximum cooling capacity and there is no candidate operating point at which the cooling capacity is equal to the required cooling capacity, the cooling system ECM 80 sets the candidate operating point at which the cooling capacity is closest to the required cooling capacity, i.e., the candidate operating point at which the cooling capacity is the maximum cooling capacity (here, candidate operating point P2), as the corrected operating point. Also, when there are multiple corrected operating points at which the cooling capacity is equal to the required cooling capacity, the cooling system ECM 80 selects the candidate operating point with the lower compressor rotation speed as the corrected operating point. This is because, from the viewpoint of cooling efficiency, the lower the compressor rotation speed and the higher the fan rotation speed, the higher the cooling efficiency.

[0064] 7 is a flowchart showing the processing operation of the cooling system ECM 80 when performing noise suppression control. This flowchart is executed at predetermined intervals.

[0065] First, in step S101, the cooling system ECM 80 receives and reads signals from the various sensors SW1 to SW7, the PCM 81, and the BECM 82.

[0066] Next, in step S102, the cooling system ECM 80 calculates a required cooling capacity.

[0067] Next, in step S103, the cooling system ECM 80 calculates a set compressor speed NC based on the required cooling capacity. Next, in step S104, the cooling system ECM 80 calculates a set fan speed NF based on the detection result of the second refrigerant pressure sensor SW3.

[0068] Next, in step S105, the cooling system ECM 80 determines whether the vehicle speed is less than a predetermined vehicle speed. When the vehicle speed is high, road noise is large, so that even if the cooling device 1 generates noise of a volume equal to or greater than the noise regulation value, the occupants of the vehicle 100 are unlikely to feel annoyed. For this reason, the cooling system ECM 80 does not execute noise suppression control when the vehicle speed is high. If the vehicle speed is less than the predetermined vehicle speed (YES), the cooling system ECM 80 proceeds to step S106. On the other hand, if the vehicle speed is equal to or greater than the predetermined vehicle speed (NO), the cooling system ECM 80 proceeds to step S111. The predetermined vehicle speed is a speed at which road noise of a volume equal to or greater than the noise regulation value is generated, and may be set to, for example, 20 km / h.

[0069] Next, in step S106, the cooling system ECM 80 determines whether the set compressor speed NC is greater than the limit compressor speed NCL. If the result is YES, that is, the set compressor speed NC is greater than the limit compressor speed NCL, the cooling system ECM 80 proceeds to step S108. On the other hand, if the result is NO, that is, the set compressor speed NC is equal to or less than the limit compressor speed NCL, the cooling system ECM 80 proceeds to step S107.

[0070] In step S107, the cooling system ECM 80 determines whether the set fan speed NF is greater than the limit fan speed NFL. If the result is YES, that is, the set fan speed NF is greater than the limit fan speed NFL, the cooling system ECM 80 proceeds to step S108. On the other hand, if the result is NO, that is, the set fan speed NF is equal to or less than the limit fan speed NFL, the cooling system ECM 80 proceeds to step S111.

[0071] In step S108, the cooling system ECM 80 determines the cooling capacity at each candidate operating point on the noise limit line SL.

[0072] Next, in step S109, the cooling system ECM 80 sets the candidate operating point whose cooling capacity is closest to the required cooling capacity as the modified operating point, and sets the compressor rotation speed and the fan rotation speed of the modified operating point as the modified compressor rotation speed and the modified fan rotation speed. When there is a candidate operating point whose cooling capacity is the same as the required cooling capacity, the cooling system ECM 80 sets the candidate operating point as the modified operating point. When there are multiple candidate operating points whose cooling capacity is closest to the required cooling capacity, the cooling system ECM 80 sets the candidate operating point whose compressor rotation speed is the lowest as the modified operating point.

[0073] Next, in step S110, the cooling system ECM 80 operates the cooling device 1 at the corrected compressor speed and the corrected fan speed. After step S110, the process returns.

[0074] On the other hand, in step S111, the cooling system ECM 80 operates the cooling device 1 at the set compressor rotation speed and the set fan rotation speed. After step S111, the process returns.

[0075] Effects of the First Embodiment Therefore, in the first embodiment, the system includes a compressor 3 that pressurizes the refrigerant, a fan 41 that draws outside air into a condenser 4 that cools and condenses the refrigerant pressurized by the compressor 3, a battery temperature sensor SW1 that detects the temperature of the battery module 70, a motor water temperature sensor SW5 that detects the temperature of the drive motor 102, a second refrigerant pressure sensor SW3 that detects the pressure of the refrigerant compressed by the compressor 3, and a cooling system ECM 80 that controls the compressor 3 and the fan 41. The cooling system ECM 80 calculates a required cooling capacity based on at least the detection results of the battery temperature sensor SW1 and the motor water temperature sensor SW5, calculates a set compressor rotation speed which is the rotation speed of the compressor 3 based on the required cooling capacity, calculates a set fan rotation speed which is the rotation speed of the fan 41 based on the detection result of the second refrigerant pressure sensor SW3, and sets the set compressor rotation speed When both a first condition that the set fan speed is equal to or less than a limit compressor speed NCL preset based on a predetermined noise regulation value and a second condition that the set fan speed is equal to or less than a limit fan speed NFL preset based on a predetermined noise regulation value are satisfied, the compressor 3 and the fan 41 are operated at the set compressor speed and the set fan speed, respectively, while when at least one of the first condition and the second condition is not satisfied, a corrected compressor speed is set and a corrected fan speed is set based on the corrected compressor speed so that the noise generated when the compressor 3 and the fan 41 are operated is equal to or less than the predetermined noise regulation value, and the compressor 3 and the fan 41 are operated at the corrected compressor speed and the corrected fan speed, respectively, and the corrected fan speed is set to a lower value as the corrected compressor speed is higher. In this way, by setting the fan speed based on the compressor speed rather than the refrigerant pressure so that the fan speed is lower as the compressor speed is higher, it is possible to suppress the noise during cooling while suppressing the decrease in cooling capacity as much as possible.

[0076] Moreover, in the first embodiment, an outside air temperature sensor SW4 is further provided to detect the outside air temperature, and the cooling system ECM 80 sets the corrected compressor speed and the corrected fan speed by further considering the outside air temperature. This allows the temperature of the air taken in by the fan to be considered, so that the corrected fan speed can be set more appropriately to suppress the decrease in cooling capacity as much as possible. This makes it possible to more effectively suppress the decrease in cooling capacity.

[0077] In the first embodiment, the cooling system ECM 80 sets the corrected compressor speed and the corrected fan speed so that the generated noise falls within the noise regulation value. This allows the corrected compressor speed and the corrected fan speed to be set to as high values ​​as possible. This makes it possible to more effectively suppress the decrease in cooling capacity.

[0078] In the first embodiment, the cooling system ECM 80 calculates the cooling capacity for each of a plurality of combinations of compressor speed and fan speed that generate noise that falls within the noise regulation value, and sets the combination whose cooling capacity is closest to the required cooling capacity as the modified compressor speed and modified fan speed. This makes it possible to set an appropriate modified compressor speed and modified fan speed within a range in which noise can be suppressed. This makes it possible to suppress noise during cooling while more effectively suppressing a decrease in cooling capacity.

[0079] Furthermore, in the first embodiment, when there are multiple combinations in which the cooling capacity is the same as or closest to the required cooling capacity, the cooling system ECM 80 sets the combination with the lowest compressor rotation speed as the modified compressor rotation speed and the modified fan rotation speed. This allows the compressor rotation speed to be as low as possible. The lower the compressor rotation speed, the less the amount of refrigerant that needs to be cooled, so the refrigerant can be cooled more efficiently. This improves the cooling efficiency.

[0080] (Embodiment 2) Hereinafter, the second embodiment will be described in detail with reference to the drawings. In the following description, the same reference numerals are used to designate the same parts as those in the first embodiment, and detailed description thereof will be omitted.

[0081] 8 is a schematic diagram showing a method of calculating a corrected operating point in a cooling device according to the second embodiment. In the second embodiment, when at least one of a first condition that the set compressor rotation speed is equal to or lower than the limit compressor rotation speed NCL and a second condition that the set fan rotation speed is equal to or lower than the limit fan rotation speed NFL is not satisfied, the cooling system ECM 80 calculates a first compressor rotation speed candidate whose rotation speed is higher by a certain number than the limit compressor rotation speed NCL, a first fan rotation speed candidate based on the first compressor rotation speed candidate, a second compressor rotation speed candidate whose rotation speed is lower by a certain number than the limit compressor rotation speed NCL, and a second fan rotation speed candidate based on the second compressor rotation speed candidate. Next, the cooling system ECM 80 calculates the cooling capacity when the compressor 3 and the fan 41 are operated at each of the limited operating points PL, which is a combination of the limited compressor speed NCL and the limited fan speed NFL, the first candidate operating point P4, which is a combination of the first compressor speed candidate and the first fan speed candidate, and the second candidate operating point P5, which is a combination of the second compressor speed candidate and the second fan speed candidate.The cooling system ECM 80 then selects an operating point whose cooling capacity is closest to the required cooling capacity as a corrected operating point, and sets the compressor speed and the fan speed of the corrected operating point to the corrected compressor speed and the corrected fan speed, respectively. That is, the limited operating point PL is also one of the candidate operating points.

[0082] As shown in FIG. 8, in the second embodiment, the cooling system ECM 80 calculates the first candidate operating point P4 and the second candidate operating point P5 from the noise regulation line SL. That is, the first fan speed candidate is lower than the limited fan speed NFL, and the second fan speed candidate is higher than the limited fan speed NFL. In addition, since the absolute value of the difference between the first compressor speed candidate and the limited compressor speed NCL and the absolute value of the difference between the second compressor speed candidate and the limited compressor speed NCL are the same as the fixed number, the absolute value of the difference between the first fan speed candidate and the limited fan speed NFL and the absolute value of the difference between the second fan speed candidate and the limited fan speed NFL are the same. In addition, the fixed number is set in advance.

[0083] 8, the first candidate operating point P4 has a cooling capacity closest to the required cooling capacity, and therefore the first candidate operating point P4 is selected as the corrected operating point. When there are two candidate operating points whose cooling capacity is closest to the required cooling capacity, and one of the candidate operating points has a cooling capacity lower than the required cooling capacity and the other candidate operating point has a cooling capacity higher than the required cooling capacity, the cooling system ECM 80 selects the candidate operating point whose cooling capacity is higher than the required cooling capacity as the corrected operating point.

[0084] 9 and 10 are flowcharts showing the processing operation of the cooling system ECM 80 when executing noise suppression control according to the embodiment 2. This flowchart is executed at predetermined intervals.

[0085] First, in step S201, the cooling system ECM 80 receives and reads signals from the various sensors SW1 to SW7, the PCM 81, and the BECM 82.

[0086] Next, in step S202, the cooling system ECM 80 calculates a required cooling capacity.

[0087] Next, in step S203, the cooling system ECM 80 calculates a set compressor speed NC based on the required cooling capacity.

[0088] Next, in step S204, the cooling system ECM 80 calculates a set fan speed NF based on the detection result of the second refrigerant pressure sensor SW3.

[0089] Next, in step S205, the cooling system ECM 80 determines whether the vehicle speed is less than a predetermined vehicle speed. If the vehicle speed is less than the predetermined vehicle speed (YES), the cooling system ECM 80 proceeds to step S206. On the other hand, if the vehicle speed is equal to or greater than the predetermined vehicle speed (NO), the cooling system ECM 80 proceeds to step S215.

[0090] Next, in step S206, the cooling system ECM 80 determines whether the set compressor speed NC is greater than the limit compressor speed NCL. If the result is YES, that is, the set compressor speed NC is greater than the limit compressor speed NCL, the cooling system ECM 80 proceeds to step S208. On the other hand, if the result is NO, that is, the set compressor speed NC is equal to or less than the limit compressor speed NCL, the cooling system ECM 80 proceeds to step S207.

[0091] In step S207, the cooling system ECM 80 determines whether the set fan speed NF is greater than the limit fan speed NFL. If the result is YES, that is, the set fan speed NF is greater than the limit fan speed NFL, the cooling system ECM 80 proceeds to step S208. On the other hand, if the result is NO, that is, the set fan speed NF is equal to or less than the limit fan speed NFL, the cooling system ECM 80 proceeds to step S215.

[0092] In step S208, the cooling system ECM 80 calculates a first compressor rotation speed candidate.

[0093] Next, in step S209, the cooling system ECM 80 calculates a first fan rotation speed candidate based on the first compressor rotation speed candidate.

[0094] Next, in step S210, the cooling system ECM 80 calculates a second compressor rotation speed candidate.

[0095] Next, in step S211, the cooling system ECM 80 calculates a second fan rotation speed candidate based on the second compressor rotation speed candidate.

[0096] Next, in step S212, the cooling system ECM 80 calculates the cooling capacities at the limit operating point PL, the first candidate operating point P4, and the second candidate operating point P5.

[0097] Next, in step S213, the cooling system ECM 80 sets the operating point closest to the required cooling capacity as the modified operating point, and sets the compressor rotation speed and fan rotation speed of the operating point to the modified compressor rotation speed and modified fan rotation speed.

[0098] Next, in step S214, the cooling system ECM 80 operates the cooling device 1 at the corrected compressor speed and the corrected fan speed. After step S214, the process returns.

[0099] On the other hand, in step S215, the cooling system ECM 80 operates the cooling device 1 at the set compressor rotation speed and the set fan rotation speed. After step S215, the process returns.

[0100] In the configuration of the second embodiment, the fan speed is set based on the compressor speed, so that the deterioration of the cooling capacity can be suppressed as much as possible while the noise can be suppressed. Also, the amount of calculation of the cooling system ECM 80 can be reduced as much as possible. This makes it possible to reduce power consumption as much as possible.

[0101] (Other embodiments) The technology disclosed herein is not limited to the above-described embodiment, and may be substituted without departing from the spirit and scope of the claims.

[0102] For example, in the above-described first and second embodiments, the corrective operating point is set from above the noise regulation line SL. However, the present invention is not limited to this, and the corrective operating point may be set in a region below the noise regulation line SL in the cooling capacity map, even if it is not on the noise regulation line SL.

[0103] In the above-described first and second embodiments, when at least one of the first condition and the second condition is not satisfied, the compressor rotation speed and the fan rotation speed are set to the set compressor rotation speed and the set fan rotation speed, respectively, until a corrective operating point is selected. However, the present invention is not limited to this, and when at least one of the first condition and the second condition is not satisfied, the compressor rotation speed and the fan rotation speed may be temporarily set to the limit compressor rotation speed NCL and the limit fan rotation speed NFL, respectively, until a corrective operating point is selected.

[0104] In the second embodiment described above, only three candidate operating points including the limit operating point PL are calculated, but the number of candidate operating points is not limited to this, and may be four or more.

[0105] In the above-described first and second embodiments, the cooling device 1 cools the battery module 70 by circulating the refrigerant through the heat exchanger 2. However, the present invention is not limited to this, and the cooling device 1 may further include a heat exchanger (chiller) for circulating, through the heat exchanger 2, cooling water that has exchanged heat with the refrigerant.

[0106] The above-described embodiments are merely illustrative and should not be construed as limiting the scope of the present disclosure. The scope of the present disclosure is defined by the claims, and all modifications and variations within the scope of the claims are within the scope of the present disclosure. [Industrial Applicability]

[0107] The technology disclosed herein is useful as a cooling device for an electrically driven vehicle that utilizes a refrigerant to cool electrically driven components mounted on the vehicle. [Explanation of symbols]

[0108] 1 Cooling device 2 Heat exchanger 3 Compressor 4 Condenser 41 Fan 70 Battery module (electric drive parts) 80 Cooling system ECM (controller) 100 vehicles 102 Drive motor (electric drive parts) 103 Inverter (electric drive parts) 104 Converter (electric drive parts) SW1 Battery temperature sensor (electric drive component temperature detection section) SW3 Second refrigerant pressure sensor (refrigerant pressure detection section) SW4 Outside air temperature sensor (Outside air temperature detector) SW5 Motor water temperature sensor (electric drive component temperature detection section)

Claims

1. A cooling device for an electrically driven vehicle that uses a refrigerant to cool electrically driven components mounted on the vehicle, A compressor that pressurizes the refrigerant; a fan for drawing outside air into a condenser that cools and condenses the refrigerant pressurized by the pressurizer; an electric drive component temperature detection unit for detecting a temperature of the electric drive component; a refrigerant pressure detection unit that detects the pressure of the refrigerant compressed by the compressor; a controller for controlling the pressurizer and the fan; The controller: Calculating a required cooling capacity based on at least a detection result of the electrically driven component temperature detection unit; Calculating a set pressurizer rotation speed, which is a rotation speed of the pressurizer based on the required cooling capacity; Calculating a set fan speed, which is the speed of the fan based on the detection result of the refrigerant pressure detection unit; when both a first condition that the set pressurizer rotation speed is equal to or lower than a limited pressurizer rotation speed preset based on a predetermined noise regulation value and a second condition that the set fan rotation speed is equal to or lower than a limited fan rotation speed preset based on the predetermined noise regulation value are satisfied, the pressurizer and the fan are operated at the set pressurizer rotation speed and the set fan rotation speed, respectively, while when at least one of the first condition and the second condition is not satisfied, a corrected pressurizer rotation speed is set and a corrected fan rotation speed is set based on the corrected pressurizer rotation speed so that noise when the pressurizer and the fan are operated is equal to or lower than the predetermined noise regulation value, and the pressurizer and the fan are operated at the corrected pressurizer rotation speed and the corrected fan rotation speed, respectively; 2. A cooling device for an electrically powered vehicle, comprising: a controller for controlling a fan speed of the electrically powered vehicle; a controller for controlling a fan speed of the electrically powered vehicle;

2. 2. The cooling system for an electrically powered vehicle according to claim 1, An outside air temperature detection unit for detecting the outside air temperature is further provided, The cooling device for an electrically powered vehicle, wherein the controller sets the corrected pressurizer rotation speed and the corrected fan rotation speed, respectively, by further taking into account the outside air temperature.

3. 3. The cooling device for an electrically powered vehicle according to claim 1, 2. A cooling device for an electrically driven vehicle, wherein the controller sets the corrected pressurizer rotation speed and the corrected fan rotation speed so that the generated noise falls within the noise regulation value.

4. 4. The cooling system for an electrically powered vehicle according to claim 3, the controller calculates a cooling capacity for each of a plurality of combinations of the rotation speed of the pressurizer and the rotation speed of the fan, which generates noise that falls within the noise regulation value, and sets the combination among the combinations, which has a cooling capacity closest to the required cooling capacity, as the modified pressurizer rotation speed and the modified fan rotation speed, respectively.

5. 5. The cooling system for an electrically powered vehicle according to claim 4, a controller that sets the combination having the lowest rotation speed of the pressurizer among the plurality of combinations as the corrected pressurizer rotation speed and the corrected fan rotation speed when there are a plurality of combinations whose cooling capacity is closest to the required cooling capacity.

6. 4. The cooling system for an electrically powered vehicle according to claim 3, The controller: calculating a first compressor rotation speed candidate that is a certain number of revolutions higher than the limited compressor rotation speed, and a first fan rotation speed candidate based on the first compressor rotation speed candidate; calculating a second compressor rotation speed candidate having a rotation speed lower than the limited compressor rotation speed by a certain number, and a second fan rotation speed candidate based on the second compressor rotation speed candidate; a combination of the limited pressurizer rotation speed and the limited fan rotation speed, a combination of the first pressurizer rotation speed candidate and the first fan rotation speed candidate, and a combination of the second pressurizer rotation speed candidate and the second fan rotation speed candidate, and among the combinations, a combination having a cooling capacity closest to the required cooling capacity is set as the modified pressurizer rotation speed and the modified fan rotation speed, respectively.

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