Electronic device

Abstract

This electronic device comprises: a refrigerant flow path in which a refrigerant is supplied by a refrigerant supply device selectively in either a first direction from one end to the other end of the flow path or a second direction from the other end to the one end; a plurality of heat-generating components provided along the refrigerant flow path; and a control device that, on the basis of operation information of the heat-generating components, outputs, to the refrigerant supply device, a switching command for switching the flow direction of the refrigerant that flows through the refrigerant flow path.

Description

electronic equipment

[0001] The present invention relates to an electronic device.

[0002] Conventionally, a known cooling system for an electric vehicle is the one described in Patent Document 1. The cooling system described in Patent Document 1 includes a coolant loop that cools the battery, which is a heat-generating component, and a drive train cooling loop that cools the charger, motor, and inverter, which are also heat-generating components.

[0003] A valve is provided between the coolant loop and the drivetrain cooling loop to connect or disconnect them. By switching the valve, the coolant loop and the drivetrain cooling loop can be set to either an independent state or a connected state. When the coolant loop and the drivetrain cooling loop are in the independent state, the coolant in the drivetrain cooling loop flows through the charger, motor, and inverter in that order. When the drivetrain cooling loop is in the connected state, the coolant flows through the battery, charger, motor, and inverter in that order.

[0004] U.S. Patent No. 8,336,319

[0005] In the cooling system described in Patent Document 1, the battery, charger, motor, and inverter can be connected or isolated by switching valves. However, the positional relationship of the charger, motor, and inverter with respect to the flow of coolant remains unchanged in either state, and they are arranged in the order of charger, motor, and inverter from upstream to downstream. In other words, the cooling priority remains fixed as charger, motor, and inverter. Therefore, when the heat generation status of each heat-generating component changes depending on the driving conditions of the electric vehicle and the cooling priority changes, the system must address the issue by increasing the cooling capacity of the drivetrain cooling loop or temporarily limiting torque to suppress heat generation, which impairs efficient response and maintenance of the driving conditions intended by the driver.

[0006] An electronic device according to one aspect of the present invention comprises a refrigerant flow path in which a refrigerant is selectively supplied by a refrigerant supply device in either a first direction from one end of the flow path to the other end or a second direction from the other end to the one end, a plurality of heat-generating components arranged along the refrigerant flow path, and a control device that outputs a switching command to the refrigerant supply device to switch the flow direction of the refrigerant flowing through the refrigerant flow path based on operation information of the heat-generating components.

[0007] According to the present invention, by switching the flow direction of the coolant, it is possible to efficiently cool a plurality of heat-generating components provided in the coolant flow path in accordance with the heat generation state of the components.

[0008] 1 is a diagram showing a first mode of the thermal management system in the first embodiment. FIG. 2 is a diagram showing a second mode of the thermal management system. FIG. 3 is a diagram showing a general configuration of an electronic device. FIG. 4 is a diagram showing a schematic arrangement of heat-generating components in an inverter device. FIG. 5 is a diagram explaining thermal resistance in a heat transfer path. FIG. 6 is a diagram showing a temperature estimation logic expressed by equation (3). FIG. 7 is a diagram showing a temperature estimation logic expressed by equation (7). FIG. 8 is a schematic diagram showing a flow rate / thermal resistance table in the first mode. FIG. 9 is a schematic diagram showing a flow rate / thermal resistance table in the second mode. FIG. 10 is a diagram explaining modified example 1. FIG. 11 is a diagram explaining modified example 2. FIG. 12 is a diagram showing a thermal management system in the second embodiment. FIG. 13 is a diagram showing a plurality of inverter devices provided along a refrigerant flow path.

[0009] First Embodiment An electronic device according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 11 . FIGS. 1 and 2 are diagrams showing a schematic configuration of a thermal management system 100 for an electric vehicle. FIG. 1 shows a first mode in the thermal management system 100, and FIG. 2 shows a second mode. The thermal management system 100 includes refrigerant flow paths 120a and 120b through which a refrigerant flows, and an inverter device 11 provided in the electronic device 1 is cooled by the thermal management system 100. The inverter device 11 is provided with a refrigerant flow path 110, and inlet / outlet ports 110a and 110b of the refrigerant flow path 110 are connected to the refrigerant flow path 120b. The electronic device 1 includes a control device 12 that controls the operation of the inverter device 11.

[0010] In addition to the above-mentioned refrigerant flow paths 120a and 120b, the thermal management system 100 also includes a radiator 121, a chiller 122, a pump 123, a four-way valve 124, and a controller 125 that controls them. The pump 123 causes the refrigerant to flow through the refrigerant flow path 120a in the direction indicated by the white arrow. The radiator 121 and chiller 122 are installed in this order along the refrigerant flow direction on the suction side of the pump 123. The radiator 121, which exchanges heat between the ambient air and the refrigerant, is equipped with a blower fan 126.

[0011] Four-way valve 124 is provided in refrigerant flow path 120a on the discharge side of pump 123. Four-way valve 124 is a valve that connects refrigerant flow path 120a and refrigerant flow path 120b, and has four inlet / outlet ports P1 to P4. Inlet / outlet port P1 communicates with inlet / outlet port P2, and inlet / outlet port P3 communicates with inlet / outlet port P4.

[0012] In the first mode shown in FIG. 1 , the four-way valve 124 is set to a first switching state V1. In the first switching state V1, the inlet / outlet ports P1 and P3 of the four-way valve 124 are connected to the refrigerant flow path 120a, and the inlet / outlet ports P2 and P4 are connected to the refrigerant flow path 120b. As a result, the refrigerant flows in a clockwise direction through the refrigerant flow path 120b, as indicated by the black arrows. On the other hand, in the second mode shown in FIG. 2 , the four-way valve 124 is set to a second switching state V2, in which the inlet / outlet ports P2 and P4 are connected to the refrigerant flow path 120a, and the inlet / outlet ports P1 and P3 are connected to the refrigerant flow path 120b. As a result, the refrigerant flows in a counterclockwise direction through the refrigerant flow path 120b, as indicated by the black arrows.

[0013] In this way, switching between the first mode and the second mode can be performed by switching the connection of the four-way valve 124. The switching control of the four-way valve 124 is performed by the controller 125 based on a control command C from the control device 12.

[0014] 3 is a diagram showing a schematic configuration of the electronic device 1. The electronic device 1 constitutes a power conversion device that supplies three-phase AC current to a motor M. The inverter device 11 of the electronic device 1 includes an inverter circuit 111, a gate drive circuit 112, and a smoothing capacitor 113. The inverter circuit 111 includes six switching elements S1 to S6 that constitute three-phase upper and lower arms. The switching elements S1 to S6 are formed of power semiconductors, and for example, IGBTs (Insulated Gate Bipolar Transistors) or the like are used.

[0015] The control device 12 of the electronic device 1 is composed of a computer equipped with processing devices such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), and DSP (Digital Signal Processor), non-volatile memory such as ROM (Read Only Memory), flash memory, and hard disk drive, volatile memory known as RAM (Random Access Memory), an input / output interface, and other peripheral circuits. These pieces of hardware work together to run software and realize multiple functions.

[0016] The control device 12 controls the motor M based on commands (torque commands, etc.) from the vehicle control device 101 and transmits motor status information to the vehicle control device 101. The control device 12 generates a PWM signal for supplying three-phase AC current based on the magnetic pole position of the rotor of the motor M detected by the magnetic pole position sensor 201 and the motor current value detected by the current sensor 202. The PWM signal generated by the control device 12 is input to a gate drive circuit 112. The gate drive circuit 112 generates gate drive signals for driving each of the switching elements S1 to S6 of the inverter circuit 111 based on the PWM signal and outputs the gate drive signals to each of the switching elements S1 to S6. The smoothing capacitor 113 smoothes the current generated by the on / off switching of the switching elements S1 to S6 and suppresses ripples in the DC current supplied from the battery to the inverter circuit 111.

[0017] 4 is a schematic diagram showing the arrangement of the refrigerant flow path 110 and heat-generating components in the inverter device 11. In the first mode, the refrigerant in the refrigerant flow path 110 flows from the inlet / outlet port 110a to the inlet / outlet port 110b, and in the second mode, the refrigerant flows in the opposite direction, from the inlet / outlet port 110b to the inlet / outlet port 110a.

[0018] Power modules 301, 302, and 303, which are heat-generating components, are provided along the refrigerant flow path 110. Power module 301 incorporates switching elements S1 and S4 (see FIG. 3 ) for the upper and lower arms of the U phase. Similarly, power module 302 incorporates switching elements S2 and S5 for the upper and lower arms of the V phase, and power module 303 incorporates switching elements S3 and S6 for the upper and lower arms of the W phase. Each power module 301, 302, and 303 is provided with a heat dissipation section 304, 305, and 306 for dissipating heat generated in the power modules 301, 302, and 303 to the refrigerant in the refrigerant flow path 110.

[0019] A temperature sensor 311 that detects the temperature of the refrigerant is provided in the refrigerant flow path 110. Furthermore, temperature sensors 312 and 313 that monitor the temperatures of the heat-generating parts of the power modules 301 and 303 (for example, the junction temperatures of the switching elements) are provided in the power modules 301 and 303, respectively.

[0020] 4, the temperature sensor 312 is provided so as to be in contact with the surface of the power module 301, but is actually mounted so as to be located on the heat transfer path from the heat generating portion of the power module 301 to the heat dissipation portion 304. The same is true for the temperature sensor 313, which is also mounted so as to be located on the heat transfer path from the heat generating portion of the power module 303 to the heat dissipation portion 306. The detected values ​​of the temperature sensors 311 to 313 (sensor temperatures T311, T312, T313) are input to the control device 12.

[0021] In the first mode, the refrigerant flows into the refrigerant flow path 110 from the inlet / outlet port 110a, cools the heat dissipation section 304, then the heat dissipation section 305, and then the heat dissipation section 306, and then the coolant flows out from the inlet / outlet port 110b. In the second mode, the refrigerant flows into the refrigerant flow path 110 from the inlet / outlet port 110b, cools the heat dissipation section 306, then the heat dissipation section 305, and then the heat dissipation section 304, and then the coolant flows out from the inlet / outlet port 110a.

[0022] (Temperature Estimation Method) Next, a method for estimating the temperatures of the heat-generating components (power modules 301, 302, 303) and the coolant in the inverter device 11 shown in Fig. 4 will be described. The temperature estimation is performed by the control device 12 shown in Figs.

[0023] 5 to 7 are diagrams illustrating the temperature estimation logic of the power module 301 in the inverter device 11 shown in FIG. 4. FIG. 5 is a diagram illustrating the thermal resistance in the heat transfer path of "heat generating portion inside the power module 301 → surface of the power module 301 → heat dissipation portion 304 → surrounding refrigerant." θt1 is the thermal resistance from the heat generating portion of the power module 301 to the surface of the power module 301. θt2 is the thermal resistance from the surface of the power module 301 to the surrounding refrigerant of the heat dissipation portion 304. The temperature sensor 312 is provided near the surface of the power module 301, which is on the heat transfer path.

[0024] If the thermal energy per unit time flowing from the power module 301 to the coolant via the heat dissipation unit 304 is ΔQ (W), the relationship of the following formula (1) holds for the difference (T301-T304) between the temperature T301 of the heat generating unit of the power module 301 and the temperature T304 of the coolant around the heat dissipation unit 304. Also, the relationship of the following formula (2) holds for the difference (T312-T304) between the sensor temperature T312 and the temperature T304 of the coolant around the heat dissipation unit 304. T301-T304=(θt1+θt2)ΔQ (1) T312-T304=θt2·ΔQ (2)

[0025] As a result, the relationship between the temperature difference (T301-T304) and the temperature difference (T312-T304) is expressed as in equation (3) using the conversion coefficient Ksj=(θt1+θt2) / θt2. T301-T304=Ksj·(T312-T304) (3)

[0026] That is, the estimated temperature T301e of the heat generating portion of the power module 301 is calculated by the following equation (4): T301e=Ksj·(T312−T304)+T304 (4)

[0027] FIG. 6 illustrates the temperature estimation logic expressed by equation (3).

[0028] Similarly, the temperature of the heat generating portion of the power module 303 (estimated temperature T303e) can be estimated based on the sensor temperature T313 detected by the temperature sensor 313 and the temperature T306 of the coolant around the heat dissipation portion 306.

[0029] 7 is a diagram showing the temperature estimation logic for the refrigerant temperature T304 around the heat dissipation unit 304 in FIG. 4. The above-mentioned equation (3) can be transformed into the following equation (5) using a conversion coefficient Kjs = θt2 / (θt1 + θt2). Furthermore, if the loss of the power module 301 is represented as ΔP (W), then ΔP = ΔQ, and the above-mentioned equation (1) can be expressed as the following equation (6). Note that data related to the loss ΔP is obtained in advance. T312 - T304 = (T301 - T304) Kjs (5) T301 - T304 = (θt1 + θt2) ΔP (6)

[0030] Then, from equations (5) and (6), equation (7) is obtained to calculate the estimated temperature T304e of the refrigerant around the heat dissipation portion 304. T304e=T312-(θt1+θt2)ΔP·Kjs (7)

[0031] Similarly, the refrigerant temperature around the heat dissipation unit 306 (estimated temperature T306e) can also be estimated based on the sensor temperature T313 measured by the temperature sensor 313 and the loss of the power module 303.

[0032] The temperature estimation logic expressed by equation (7) is shown in a block diagram as in Figure 7. The estimated temperature T304e is input to the flow rate / thermal resistance table T, and the thermal resistance θt2 is output from the flow rate / thermal resistance table T. Then, the loss ΔP is multiplied by the thermal resistance (θt1 + θt2) based on the thermal resistance θt2 and the preset thermal resistance θt1. Note that the thermal resistance θt2 in Figure 5 is also obtained based on the flow rate / thermal resistance table T.

[0033] 5 to 7, it is possible to estimate the temperature T301e of the heat-generating portion of the power module 301 based on the sensor temperature T312 and the loss ΔP(301) of the power module 301. That is, the control device 12 can more accurately perform protection control of the power module 301 by using the estimated temperature T301e of the heat-generating portion of the power module 301 instead of the temperature near the surface of the power module 301 detected by the temperature sensor 312 (sensor temperature T312).

[0034] The above-mentioned thermal resistance θt1 is the thermal resistance from the heat generating portion of the power module 301 to the surface of the power module 301, and is therefore determined almost independently of the flow of the coolant. On the other hand, the thermal resistance θt2 from the surface of the power module 301 to the coolant around the heat dissipation portion 304 depends on the shape of the coolant flow path 110, the direction of coolant flow, the flow rate of the coolant, etc. Furthermore, the thermal management system 100 shown in Fig. 1 uses a system that varies the flow rate of the pump 123 in accordance with the coolant flow rate.

[0035] Therefore, the value of thermal resistance θt2 in the first mode in Fig. 1 will be different from the value of thermal resistance θt2 in the second mode in Fig. 2. For example, the flow rate / thermal resistance table T shown in Fig. 6 is set individually for each of the first mode and the second mode. Hereinafter, the flow rate / thermal resistance table for the first mode will be referred to as T1, and the flow rate / thermal resistance table for the second mode will be referred to as T2.

[0036] In this embodiment, a table T (T1, T2) relating to the thermal resistance θt1 and the thermal resistance θt2 is stored in advance in a storage unit (not shown) of the control device 12. In this embodiment, as described above, the thermal resistance θt1 is determined regardless of the flow (flow rate and flow direction) of the refrigerant, but the value may change depending on the flow, as in the case of the thermal resistance θt2.

[0037] 8 is a schematic diagram showing an example of a flow rate / thermal resistance table T1 in the first mode. The flow rate / thermal resistance table T1 is composed of a flow rate table T11, which represents the relationship between the refrigerant temperature and the refrigerant flow rate, and a thermal resistance table T12, which represents the relationship between the refrigerant flow rate and the thermal resistance θt2. As shown in FIG. 4, in the first mode, the refrigerant in the refrigerant flow path 110 flows from the inlet / outlet port 110a to the inlet / outlet port 110b. In the first mode, the sensor temperature T311 detected by the temperature sensor 311 is used as the reference temperature for calculating the flow rate and the thermal resistance. When the sensor temperature T311 is input into the flow rate / thermal resistance table T1, the thermal resistance θt2 is output.

[0038] 1 and 2, the flow rate of the coolant flowing through the coolant flow paths 120a and 120b is controlled to a flow rate corresponding to the coolant temperature, as shown in the flow rate table T11. For example, the flow rate of the coolant is controlled to increase as the temperature of the inflowing coolant increases. When the sensor temperature T311 is input into the flow rate table T11, the flow rate R1 corresponding to the sensor temperature T311 is output from the flow rate table T11.

[0039] The thermal resistance table T12 in Fig. 8 shows the relationship between the flow rate and the thermal resistance θt2 when the refrigerant flows in the refrigerant flow direction (inlet / outlet port 110a → inlet / outlet port 110b) in the first mode shown in Fig. 4. When the flow rate R1 output from the flow rate table T11 is input to the thermal resistance table T12, the thermal resistance θt2 corresponding to the flow rate R1 is output from the thermal resistance table T12.

[0040] 9 is a schematic diagram showing an example of the flow rate / thermal resistance table T2 in the second mode. The flow rate / thermal resistance table T2 is composed of a flow rate table T21 and a thermal resistance table T22. In the second mode, the estimated refrigerant temperature T306e around the heat dissipation unit 306 is used as the reference temperature for calculating the flow rate and thermal resistance. The estimated temperature T306e is calculated using the temperature estimation logic shown in FIG. 7. When the estimated refrigerant temperature T306e is input into the flow rate / thermal resistance table T2, the thermal resistance θt2 is output.

[0041] The flow rate table T21 represents the relationship between the temperature and flow rate of the refrigerant flowing into the refrigerant flow path 110 in the second mode, and can be substantially the same as the flow rate table T11 described above. The thermal resistance table T22 represents the relationship between the flow rate and the thermal resistance θt2 when the refrigerant flows in the refrigerant flow direction (inlet / outlet port 110b → inlet / outlet port 110a) in the second mode shown in Figure 4. As such, since the refrigerant flow direction in the thermal resistance table T22 is opposite to that in the first mode, the relationship between the flow rate and the thermal resistance generally differs between the thermal resistance table T22 and the thermal resistance table T22.

[0042] As described above, by using the flow rate / thermal resistance table T (T1, T2) shown in Figures 8 and 9, it is possible to calculate the thermal resistance from the refrigerant temperature (sensor temperature T311, estimated temperature T306e). Then, by applying the temperature estimation logic shown in Figures 6 and 7 using the flow rate / thermal resistance table T, it is possible to estimate the temperature T301e of the heat-generating portion of the power module 301 based on the sensor temperature T312 and the loss ΔP(301) of the power module 301. In other words, by using the estimated temperature T301e of the heat-generating portion of the power module 301 instead of the temperature near the surface of the power module 301 detected by the temperature sensor 312 (sensor temperature T312), the control device 12 can more accurately perform protection control of the power module 301.

[0043] (Protection Control) Next, an example of protection control based on the above-mentioned temperature estimation will be described. As described above, the flow rate tables T11 and T21 are tables for determining the refrigerant flow rate in the refrigerant flow path 110, and in this embodiment, the same table (T11 = T21) is used in both the first and second modes. Furthermore, the thermal resistance tables T12 and T22 are tables for determining the thermal resistance θt2 in each power module, and a common table is used for each of the power modules 301 to 303. In the first mode, the thermal resistance table T12 is used, and in the second mode, the thermal resistance table T22 is used.

[0044] The heat dissipation sections 304 to 306 of each power module 301 to 303 are provided along the refrigerant flow path 110. Because thermal energy is released from the heat dissipation sections 304 to 306 to the refrigerant in the refrigerant flow path 110, the refrigerant temperature increases toward the downstream side of the refrigerant flow. As a result, the temperature of the heat-generating section of the power module disposed downstream of the refrigerant flow path 110 tends to increase.

[0045] 4, in the first mode, the refrigerant flows from the inlet / outlet port 110a to the inlet / outlet port 110b, so that if the heat generation amounts are the same, the temperatures T301, T302, and T303 of the heat generating parts of the power modules 301, 302, and 303 are T301 < T302 < T303. Conversely, in the second mode, the refrigerant flows from the inlet / outlet port 110b to the inlet / outlet port 110a, so that T301 > T302 > T303.

[0046] Assume that the upper limit temperature control for the heat-generating portion of each of the power modules 301 to 303 is Tu. If the temperature T303 of the heat-generating portion of the downstream power module 303 in the first mode becomes T303 > Tu, the control device 12 sends a control command C to the controller 125 to switch the four-way valve 124 from the first switching state V1 (first mode) shown in FIG. 1 to the second switching state V2 (second mode) shown in FIG. 2. This reverses the refrigerant flow direction in the refrigerant flow path 110, and the refrigerant flows from the inlet / outlet port 110b to the inlet / outlet port 110a. As a result, the cooling capacity for the heat-generating portion of the power module 303 increases, and the temperature T303 drops below the upper limit temperature control Tu.

[0047] On the other hand, if the temperature T301 of the heat-generating portion of the downstream power module 301 becomes T301 > Tu in the second mode, the control device 12 sends a control command C to the controller 125 to switch the four-way valve 124 from the second switching state V2 (second mode) to the first switching state V1 (first mode). As a result, the cooling capacity for the heat-generating portion of the power module 301 increases, and the temperature T301 drops below the upper limit temperature Tu.

[0048] In this embodiment, a control command C for switching the flow direction of the refrigerant flowing through the refrigerant flow path 110 is sent to the controller 125 based on the estimated temperature of the heat-generating portion, which is the operational information of the power module. Therefore, by switching the flow direction of the refrigerant so that the heat-generating components requiring higher cooling performance can be effectively cooled, it is possible to efficiently cool the multiple heat-generating components (power modules 301 to 303) arranged in series along the refrigerant flow path 110 according to the environment, operating mode, etc., in accordance with the heat generation status.

[0049] Consider a combination of the inverter schematic diagram of this embodiment shown in FIG. 3 and power modules 301 to 303 shown in FIG. 4. A U-phase power module is formed by incorporating an upper and lower pair of switching element S1 and switching element S4 into power module 301, a V-phase power module is formed by incorporating an upper and lower pair of switching element S2 and switching element S5 into power module 302, and a W-phase power module is formed by incorporating switching element S3 and switching element S6 into power module 303. The intermediate portions of the upper and lower switching elements for the U, V, and W phases are connected to the three-phase terminals of motor M. Inverter 111 generates different magnetic fields for each phase angle by passing positive and negative currents, large and small, for each phase depending on the phase of motor M, thereby controlling the rotation speed and torque of motor M.

[0050] The heat generation amount of the power modules varies depending on the magnitude of the current in each of the UVW phases at each phase angle. However, when the motor is rotating at high speed, the heat generation amount is smoothed and becomes nearly uniform. On the other hand, when there is almost no phase angle transition, heat generation differences occur between the UVW power modules. For example, when the vehicle is stopped on a slope or climbing a bump, the current phase transitions in the UVW phases may be extremely slow or even completely stopped. In this case, a large current may flow only through a specific power module (e.g., the U-phase power module), causing the temperature of only that phase to rise. In such cases, the power module with a rising temperature can be treated as a heat-generating component with a high cooling priority, and a switching device (e.g., a four-way valve) can be controlled to position that power module upstream in the refrigerant flow path. By prioritizing cooling of the power module with a rising temperature, the frequency of torque limitation can be reduced.

[0051] In this embodiment, the temperature of the heat-generating portion is estimated by finding the thermal resistance θt2 using flow rate / thermal resistance tables T1 and T2 corresponding to the flow direction of the refrigerant in the refrigerant flow path 110. This improves the accuracy of estimating the temperature of the heat-generating portion, and allows for more appropriate protection control by switching control of the four-way valve 124.

[0052] <Modification 1> FIG. 10 is a diagram illustrating Modification 1 of the above-described embodiment. When switching between the first mode (first switching state V1) and the second mode (second switching state V2) described above, a fluctuation period during which one mode switches to the other is assumed. FIG. 10 is a diagram illustrating the refrigerant flow rate and the torque limit control of the motor M when switching from the first mode to the second mode, where the horizontal axis represents time t and the vertical axis represents the flow rate and torque. The solid line in FIG. 10 represents the flow rate. Here, the flow rate in the first mode is represented as a positive value, and the flow rate in the second mode, in which the refrigerant flow direction is reversed, is represented as a negative value. In other words, the refrigerant flow direction is represented by the positive or negative value of the flow rate.

[0053] 10, when the flow rate in the first mode is R1, the flow rate value when the four-way valve 124 is switched to the second mode and the flow rate stabilizes becomes R2. When the value of R1 changes, R2 also changes accordingly.

[0054] When switching from the first mode to the second mode, the flow rate of the refrigerant flowing from the inlet / outlet port 110a to the inlet / outlet port 110b of the refrigerant flow path 110 gradually decreases. After the flow rate reaches 0, the refrigerant starts to flow from the inlet / outlet port 110b to the inlet / outlet port 110a, and the flow rate gradually increases, eventually settling at the flow rate (-R2) in the second mode.

[0055] On the other hand, when switching from the second mode to the first mode, the flow rate increases from the flow rate (-R2) in the second mode to the flow rate R1 in the first mode during the fluctuation period. Hereinafter, the fluctuation period when switching from the first mode to the second mode will be referred to as the third mode, and the fluctuation period when switching from the second mode to the first mode will be referred to as the fourth mode.

[0056] In the third mode, in which the flow rate changes from R1 to −R2, a unique flow rate / thermal resistance table T3 is set, separate from the first and second modes in which the flow rate is stable. The reference temperature for the post-change mode (second mode) is used as the reference temperature for calculating the flow rate and thermal resistance using the flow rate / thermal resistance table T3. In other words, the estimated temperature T306e of the refrigerant around the heat dissipation unit 306 is used as the reference temperature.

[0057] Similarly, in the fourth mode when the second mode is switched to the first mode, a unique flow rate / thermal resistance table T4 is set according to the fourth mode. In the fourth mode, the mode after the change is the first mode, so the sensor temperature T311 detected by the temperature sensor 311 is used as the reference temperature for calculating the flow rate and thermal resistance.

[0058] During the mode switching period (modes 3 and 4) when the refrigerant flow direction is reversed, the flow rate tables T11 and T21, which are used when the refrigerant flow direction is fixed, cannot be used. Various methods are possible for setting the flow rate / thermal resistance tables T3 and T4. As an example, the time Δt of the mode switching period is set according to the flow rate before and after switching, and the flow rate during the mode switching period is estimated by assuming that the flow rate changes at a constant rate during the time Δt. The thermal resistance is then estimated based on the estimated flow rate and the thermal resistance tables T12 and T22 shown in Figures 8 and 9, and protection control during the transition period is performed based on the estimated temperature of the heat-generating component based on the thermal resistance.

[0059] Specifically, we first assume that the relationship between the flow rates before and after switching is unique. That is, in the case of a flow path configuration in which the flow rate becomes (-R2) when switching from the first mode with a flow rate of R1 to the second mode, the flow rate becomes R1 when switching from the second mode with a flow rate of (-R2) to the first mode. Next, we assume that the mode switching time Δt is the same when switching from the first mode to the second mode and when switching from the second mode to the first mode. That is, Δt (in the case of R1 → -R2) = Δt (in the case of -R2 → R1), and it can be expressed as Δt(R1, R2) in either case.

[0060] Also, it is assumed that the flow rate changes at a constant rate as a flow rate change pattern. Therefore, in the third mode when switching from the first mode to the second mode as in the case of Figure 10, the flow rate R changes as shown in the following equation (8). Conversely, in the fourth mode when switching from the second mode to the first mode, the flow rate R changes as shown in the following equation (9). Then, the thermal resistance is estimated based on the flow rate calculated by equations (8) and (9), and protection control during the transient period is performed based on the estimated temperature of the heat-generating part based on that thermal resistance. R = R1 - {(R1 + R2) / Δt(R1, R2)} t ... (8) R = -R2 + {(R1 + R2) / Δt(R1, R2)} t ... (9)

[0061] In the third and fourth modes, the flow rate of the refrigerant is smaller than in the first and second modes, and the cooling performance for the power module is further reduced. Therefore, in order to prevent excessive heat generation from the power module in the third and fourth modes, the torque limit values ​​τ3 and τ4 in the third and fourth modes are set lower than the torque limit values ​​τ1 and τ2 in the first and second modes.

[0062] As described above, in the first modification, during the fluctuation period (third mode, fourth mode), which is a transitional period of mode switching, a unique flow rate / thermal resistance table is set in accordance with the change in flow rate during the fluctuation period. As a result, it is possible to improve the accuracy of estimating the temperature of the heat-generating part during the fluctuation period, and it is possible to appropriately perform the protection operation of the power module even during the fluctuation period.

[0063] <Modification 2> Figure 11 is a diagram illustrating Modification 2 of the above-described embodiment. In Modification 2, the normality or abnormality of the refrigerant flow path system is determined based on the sensor temperature T311 and the estimated temperature T306e related to the refrigerant temperature. When the refrigerant flow in the refrigerant flow path system is normal, in the first mode, the estimated temperature T306e, which is the refrigerant temperature on the downstream side of the refrigerant flow path 110, is higher than the sensor temperature T311, which is the refrigerant temperature on the upstream side. On the other hand, in the second mode, in which the refrigerant flows in the opposite direction, the magnitude relationship is reversed, i.e., T306e < T311.

[0064] However, if a decrease in flow rate or a refrigerant leak occurs in the refrigerant flow path system, the temperatures of the power modules 301, 302, and 303 will rise excessively due to insufficient cooling. Therefore, in both the first and second modes, T306e > T311. That is, if T306e > T311 in both the first and second modes, the control device 12 determines that an abnormality has occurred in the refrigerant flow path system. In this way, it is possible to determine whether the refrigerant flow path system is normal or abnormal based on the magnitude relationship between the estimated temperature T306e and the sensor temperature T311.

[0065] Second Embodiment Next, a second embodiment of the present invention will be described with reference to Figures 12 and 13. Figure 12 is a diagram showing a thermal management system in the second embodiment. Figure 13 is a diagram showing inverter units 11A and 11B provided along a refrigerant flow path 120b.

[0066] 1, 2, and 4, the four-way valve 124 is switched between the first switching state V1 and the second switching state V2 to switch the flow direction of the refrigerant flowing through the refrigerant flow path 110 of the inverter device 11 between the first mode and the second mode. By performing such switching control, protection control of the multiple power modules 301 to 303 provided along the refrigerant flow path 110 is appropriately performed.

[0067] On the other hand, in the second embodiment, as shown in Fig. 12, a plurality of inverter devices 11A, 11B are arranged as heat-generating components along a refrigerant flow path 120b. Here, each of the inverter devices 11A, 11B has the same configuration as the inverter device 11 in Fig. 4, and each of the inverter devices 11A, 11B is provided with temperature sensors 311 to 313, and the respective sensor temperatures T311, T312, T313 are input to the control device 12. Each of the inverter devices 11A, 11B is controlled by the control device 12. The other configurations are the same as those shown in Figs. 1 and 2.

[0068] 12 shows a first mode in which the four-way valve 124 is set to the first switching state V1, in which the refrigerant flows from the inverter device 11A to the inverter device 11B in that order. In a second mode in which the four-way valve 124 is set to the second switching state V2, the refrigerant flows from the inverter device 11B to the inverter device 11A in that order. In the first embodiment described above, the power modules 301 to 303 provided in the inverter device 11 are treated as heat-generating components. In the second embodiment, on the other hand, as shown in FIG. 13, the inverter devices 11A and 11B are treated as heat-generating components, and protection control is performed for each of them.

[0069] 13 shows inverter devices 11A and 11B as heat-generating components arranged so that the refrigerant flows from right to left in the first mode, similar to the case shown in FIG. 4. In this case, the sensor temperature T311 of inverter device 11A is used as the reference temperature for calculating the flow rate and thermal resistance in the first mode. Meanwhile, the estimated temperature T306e of the refrigerant around heat dissipation unit 306 in inverter device 11B is used as the reference temperature for calculating the flow rate and thermal resistance in the second mode.

[0070] Although the description will be omitted, the temperature estimation method and protection control in the first embodiment described above can also be applied to the configuration in Fig. 13. Furthermore, the methods of Modifications 1 and 2 can also be applied.

[0071] In the second embodiment, by separately setting thermal resistance and flow rate tables corresponding to the first and second modes, the cooling capacity and protection limits for each of the inverter devices 11A and 11B can be varied depending on the output state of the inverter devices 11A and 11B. In this way, with the configuration of the second embodiment, the refrigerant flow direction can be switched depending on which of the inverter devices 11A and 11B is to be given priority for cooling, thereby always achieving optimal cooling.

[0072] The first and second embodiments differ in whether the heat-generating component group is a power module or an inverter device, but the present invention can be applied to either embodiment. Examples of heat-generating component configurations as in the first embodiment include the configuration shown in Fig. 4 of the first embodiment, as well as a case in which a freewheel diode and an IGBT (Insulated Gate Bipolar Transistor) in a power module are treated as heat-generating components.

[0073] On the other hand, examples of heat-generating component configurations such as those of the second embodiment include (a) a lithium-ion battery device and an inverter device, (b) a front inverter device and a rear inverter device in a four-wheel drive electric vehicle, (c) a motor and an inverter device, etc. In any case, the refrigerant flow is switched by a switching device in accordance with changes in the cooling priority of the heat-generating components so that the heat-generating component with the higher cooling priority is located upstream.

[0074] According to the above-described embodiment and modified examples, the following advantageous effects are achieved.

[0075] (C1) As shown in Figures 1, 2, 4, etc., electronic device 1 includes a refrigerant flow path 110 to which a refrigerant is selectively supplied by a thermal management system 100 (refrigerant supply device) in either a first direction from one end of the flow path to the other end or a second direction from the other end to the one end, power modules 301 to 303 (multiple heat-generating components) provided along refrigerant flow path 110, and a control device 12 that outputs a control command (switching command) to a controller 125 of thermal management system 100 to switch the flow direction of the refrigerant flowing through refrigerant flow path 110 based on operation information of power modules 301 to 303.

[0076] With this configuration, it is possible to switch the flow direction of the refrigerant so that the heat-generating components (power modules 301 to 303) arranged along the refrigerant flow path 110 have a higher cooling priority at the upstream side depending on the environment, driving mode, etc., thereby enabling efficient cooling according to the heat generation situation. The following effects are obtained with the above-mentioned (a) lithium-ion battery device and inverter device, (b) front-side inverter device and rear-side inverter device in a four-wheel drive electric vehicle, and (c) motor and inverter device.

[0077] (a) In a combination of a lithium-ion battery device and an inverter device, for example, continuous high-power operation can cause the lithium-ion battery to continuously discharge, generating heat and potentially deteriorating. In such a case, the lithium-ion battery is treated as a heat-generating component with a higher cooling priority, and a switching device (such as a four-way valve) is controlled to position the lithium-ion battery upstream of the cooling medium path where the cooling temperature is lower, thereby suppressing temperature fluctuations in the lithium-ion battery. This reduces the deterioration of the lithium-ion battery. However, even during such a continuous operation, protection of the power module within the inverter device may be required if a high current is suddenly passed through the inverter device to drive the motor at high torque. In such a case, the frequency of torque limitation can be reduced by controlling the inverter device to be positioned upstream of the cooling medium path where the cooling temperature is lower.

[0078] (b) In a four-wheel-drive electric vehicle, when a front inverter unit and a rear inverter unit are combined, for example, during a long, continuous downhill stretch or when the vehicle repeatedly stops and starts on a downhill stretch due to traffic lights or signs, the front inverter may continuously or intermittently generate a high-torque regenerative current. In such cases, by controlling the front inverter unit to be located upstream of the cooling medium path where the cooling temperature is lower, regenerative braking operation can be continued without suppressing regenerative torque to protect the inverter unit. As a result, the amount of regenerative charging energy to the lithium-ion battery unit can be increased, improving the vehicle's mileage. On the other hand, for example, continuous uphill climbing with a heavy load or continuous stop-and-go driving can generate continuous or intermittent high loads on the rear inverter. In such cases, by prioritizing cooling of the rear inverter, the vehicle can be able to climb uphill without stopping or sliding downhill due to torque restrictions.

[0079] (c) In a combination of a motor and an inverter device, for example, sudden acceleration may cause a transition from low rotation to high rotation while maintaining high torque, resulting in high motor output. In such a case, the temperature deviation between the UVW phases of the inverter device as described above is smoothed, lowering the inverter's cooling priority, while the motor continues to operate at high output. In this case, by treating the motor as a heat-generating component with a higher cooling priority and controlling it to be located upstream of the cooling medium path where the cooling temperature is lower, torque limiting control to prevent demagnetization due to high temperature of the motor magnets can be reduced, allowing for higher torque to be maintained at sudden acceleration.

[0080] (C2) In (C1) above, as shown in FIGS. 4, 8, 9, etc., when the control device 12 performs control based on the temperature of the refrigerant flowing through the refrigerant flow path 110 and the temperatures of the power modules 301-303, if the refrigerant flows in a first direction, the control device 12 controls the operation of the heat-generating components using control based on the flow rate / thermal resistance table T1 of FIG. 8 (first control mode). On the other hand, if the refrigerant flows in a second direction, the control device 12 controls the operation of the heat-generating components using control based on the flow rate / thermal resistance table T2 of FIG. 9 (second control mode). By performing such control, the power modules 301-303, which are heat-generating components, are protected. In this way, by using the flow rate / thermal resistance tables T1 and T2 according to the flow direction of the refrigerant in the refrigerant flow path 110, the accuracy of temperature estimation of the heat-generating components can be improved, and protection control by switching control of the four-way valve 124 can be more appropriately performed.

[0081] 8, 9, etc., in (C2), the control device 12 estimates the flow rate of the refrigerant based on the temperature of the refrigerant flowing through the refrigerant flow path 110, estimates the temperatures of the power modules 301 to 303 based on the estimated flow rate, and controls the operation of the power modules 301 to 303 based on the estimated temperatures. By performing such control, it is possible to more appropriately perform protection control for the power modules 301 to 303.

[0082] (C4) In (C2) above, as shown in FIG. 10 and other figures, the control device 12 controls the operation of the power modules 301-303 in a third control mode (third mode or fourth mode) during a transition period (the third mode period in FIG. 10 ) in which the flow direction of the refrigerant flowing through the refrigerant flow path 110 switches between the first direction and the second direction. In the third and fourth modes, the control device 12 estimates the flow rate of the refrigerant during the transition period and controls the operation of the power modules 301-303 during the transition period based on the estimated flow rate. As a result, appropriate protection control can be performed even during the transition period.

[0083] (C5) In (C2) above, as shown in FIGS. 4, 11, etc., the control device 12 includes a temperature sensor 311 (first temperature sensor) for detecting a first refrigerant temperature (sensor temperature T311) at one end of the refrigerant flow path 110, and a temperature sensor 313 (second temperature sensor) for detecting a second refrigerant temperature (estimated temperature T306e) at the other end. The control device 12 determines that an abnormality has occurred in the cooling function of the refrigerant when the magnitude relationship between the sensor temperature T311 and the estimated temperature T306e is the same when the refrigerant is supplied in the first direction and when the refrigerant is supplied in the second direction. In this way, the control device 12 can determine an abnormality in the cooling function based on the detection values ​​of the temperature sensors 311 and 313.

[0084] The above describes embodiments and modifications of the present invention, but the above embodiments merely illustrate some of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0085] 1...electronic device, 2...battery, 11...inverter device, 12...controller, 100...thermal management system, 101...vehicle control device, 110, 120a, 120b...refrigerant flow path, 111...inverter circuit, 121...radiator, 122...chiller, 123...pump, 124...four-way valve, 125...controller, 301, 302, 303...power module, 304, 305, 306...heat dissipation section, 311, 312, 313...temperature sensor, C...control command, M...motor, S1 to S6...switching elements, T1, T2...flow rate / thermal resistance table

Claims

1. An electronic device comprising: a refrigerant flow path through which a refrigerant is selectively supplied by a refrigerant supply device in either a first direction from one end of the flow path to the other end, or a second direction from the other end to the one end; a plurality of heat-generating components arranged along the refrigerant flow path; and a control device that outputs a switching command to the refrigerant supply device to switch the flow direction of the refrigerant flowing through the refrigerant flow path based on operation information of the heat-generating components.

2. An electronic device as described in claim 1, wherein the control device protects the heat-generating components by controlling the operation of the heat-generating components in a first control mode when the refrigerant flows in the first direction, and by controlling the operation of the heat-generating components in a second control mode when the refrigerant flows in the second direction, based on the temperature of the refrigerant flowing through the refrigerant flow path and the temperature of the heat-generating components.

3. An electronic device according to claim 2, wherein the control device estimates a flow rate of the refrigerant based on a temperature of the refrigerant flowing through the refrigerant flow path, estimates a temperature of the heat-generating component based on the estimated flow rate, and controls the operation of the heat-generating component based on the estimated temperature.

4. An electronic device as described in claim 2, wherein the control device controls the operation of the heat-generating component in a third control mode during a transitional period in which the flow direction of the refrigerant flowing through the refrigerant flow path switches between the first direction and the second direction, and in the third control mode, estimates the flow rate of the refrigerant during the transitional period, and controls the operation of the heat-generating component during the transitional period based on the estimated flow rate.

5. An electronic device as described in claim 2, wherein the control device comprises a first temperature sensor for acquiring a first refrigerant temperature at the one end of the refrigerant flow path and a second temperature sensor for acquiring a second refrigerant temperature at the other end, and the control device determines that an abnormality has occurred in the cooling function of the refrigerant when the magnitude relationship between the first refrigerant temperature and the second refrigerant temperature is the same when the refrigerant is supplied in the first direction and when the refrigerant is supplied in the second direction.

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