Control method, control device, and control program

Abstract

To appropriately derive a saturation temperature and a loss at the saturation temperature of a power conversion device.SOLUTION: A control device 50 includes: a loss characteristic derivation unit 51 that derives a loss characteristic Lc representing a loss of a power conversion device 10 for each temperature on the basis of operating conditions of a first motor generator MG1; a thermal resistance derivation unit 53 that derives a thermal resistance Rt of the power conversion device 10 on the basis of cooling conditions by a cooling device 20; a thermal resistance characteristic derivation unit 54 that derives a thermal resistance characteristic Rc of the power conversion device 10 on the basis of the loss characteristic Lc and the thermal resistance Rt; a saturation temperature and loss-at-saturation temperature derivation unit 55 that derives a saturation temperature Tsat and a loss at the saturation temperature PlsTsat of the power conversion device 10 on the basis of the loss characteristic Lc and the thermal resistance characteristic Rc; and a vehicle control unit 56 that controls a vehicle 1 on the basis of the saturation temperature Tsat and the loss at the saturation temperature PlsTsat.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control method, a control device, and a control program. [Background technology]

[0002] In recent years, efforts to realize a low-carbon or carbon-free society have been gaining momentum as a concrete measure against global climate change. Reductions in CO2 emissions and improvements in energy efficiency are also required for vehicles such as automobiles, and research and development is being conducted on electrification technologies to electrify their drive sources.

[0003] Patent Document 1 listed below discloses a technology that calculates the power loss for each motor temperature when driving a motor at a predicted operating point, the operating speed of the fan and pump for each motor temperature, and the power consumption of the fan and pump when operating at that operating speed, calculates the sum of the motor power loss, fan power consumption, and pump power consumption for each motor temperature, and sets the motor temperature at which this sum is smallest as the target motor temperature.

[0004] Furthermore, Patent Document 2 listed below discloses a technology in which the loss that may occur in the inverter is calculated from the required output of the motor, and the discharge rate of the pump and the amount of cooling air supplied by the fan are controlled according to the calculation results. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5417123 [Patent Document 2] Patent No. 5258079 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above-mentioned conventional technology, there has been no sufficient consideration given to technology for deriving the saturation temperature, which is the temperature reached by a power conversion device when the motor generator is operated under specified operating conditions and the power conversion device that exchanges power with the motor generator is cooled under specified cooling conditions, and the loss at saturation temperature, which is the loss of the power conversion device when it is at that saturation temperature, and in this regard there is room for improvement.

[0007] The present invention provides a control method, a control device, and a control program that can appropriately derive the saturation temperature and the loss at saturation temperature of a power conversion device, thereby contributing to improving energy efficiency. [Means for solving the problem]

[0008] One aspect of the present invention is A control method executed by a computer for controlling a moving object including a motor generator, a power conversion device that exchanges electric power with the motor generator, and a cooling device that cools the power conversion device, comprising: The computer deriving loss characteristics representing losses for each temperature of the power conversion device when the motor generator is operated under operating conditions of the motor generator; deriving a thermal resistance of the power conversion device when the power conversion device is cooled under a cooling condition based on the cooling condition of the power conversion device by the cooling device; deriving a thermal resistance characteristic representing an attained temperature for each loss of the power conversion device based on the loss characteristic and the thermal resistance; deriving a saturation temperature, which is the temperature reached by the power conversion device when the motor generator is operated under the operating conditions and the power conversion device is cooled under the cooling conditions, and a loss at saturation temperature, which is the loss of the power conversion device when the saturation temperature is reached, based on the loss characteristics and the thermal resistance characteristics; controlling the moving body based on the saturation temperature and / or the loss at the saturation temperature; It is a control method for performing processing.

[0009] Another aspect of the present invention is A control device for controlling a moving body including a motor generator, a power conversion device that exchanges electric power with the motor generator, and a cooling device that cools the power conversion device, a loss characteristic deriving unit that derives, based on an operating condition of the motor generator, a loss characteristic that represents a loss for each temperature of the power conversion device when the motor generator is operated under the operating condition; a thermal resistance derivation unit that derives, based on a cooling condition of the power conversion device by the cooling device, a thermal resistance of the power conversion device when the power conversion device is cooled under the cooling condition; a thermal resistance characteristic derivation unit that derives thermal resistance characteristics that represent an attained temperature for each loss of the power conversion device based on the loss characteristics derived by the loss characteristic derivation unit and the thermal resistance derived by the thermal resistance derivation unit; a saturation temperature / loss at saturation temperature derivation unit that derives a saturation temperature, which is the temperature reached by the power conversion device when the motor generator is operated under the operating conditions and the power conversion device is cooled under the cooling conditions, and a loss at saturation temperature, which is the loss of the power conversion device at the saturation temperature, based on the loss characteristic and the thermal resistance characteristic derived by the thermal resistance characteristic derivation unit; a moving body control unit that controls the moving body based on the saturation temperature and / or the loss at saturation temperature derived by the saturation temperature / loss at saturation temperature derivation unit; The control device is provided with:

[0010] Another aspect of the present invention is A control program for causing a computer to execute predetermined processing to control a moving body including a motor generator, a power conversion device that exchanges electric power with the motor generator, and a cooling device that cools the power conversion device, the control program comprising: The computer, deriving loss characteristics representing losses for each temperature of the power conversion device when the motor generator is operated under operating conditions of the motor generator; deriving a thermal resistance of the power conversion device when the power conversion device is cooled under a cooling condition based on the cooling condition of the power conversion device by the cooling device; deriving a thermal resistance characteristic representing an attained temperature for each loss of the power conversion device based on the loss characteristic and the thermal resistance; deriving a saturation temperature, which is the temperature reached by the power conversion device when the motor generator is operated under the operating conditions and the power conversion device is cooled under the cooling conditions, and a loss at saturation temperature, which is the loss of the power conversion device when the saturation temperature is reached, based on the loss characteristics and the thermal resistance characteristics; controlling the moving body based on the saturation temperature and / or the loss at the saturation temperature; It is a control program that executes the processing. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a control method, a control device, and a control program that are capable of appropriately deriving the saturation temperature and the loss at saturation temperature of a power conversion device. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing an example of a schematic configuration of a vehicle 1 according to this embodiment. [Figure 2] FIG. 2 is a block diagram showing an example of the functional configuration of the control device 50. As shown in FIG. [Figure 3] FIG. 3 is a flowchart showing an example of processing executed by the control device 50. [Figure 4] FIG. 4 is a diagram showing an example of a method for deriving the first saturation temperature Tsat1 and the loss at the first saturation temperature PlsTsat1 in the first use example. [Figure 5] FIG. 5 is a diagram showing an example of a method for deriving the second saturation temperature Tsat2 and the loss at the second saturation temperature PlsTsat2 in the first use example. [Figure 6]FIG. 6 is a diagram showing an example of a method for deriving the third saturation temperature Tsat3 and the loss at the third saturation temperature PlsTsat3 in the first use example. [Figure 7] FIG. 7 is a diagram showing an example of a method for searching for an optimum duty in the first use example. [Figure 8] FIG. 8 is a diagram showing an example of a method for deriving the first saturation temperature Tsat1 and the loss at the first saturation temperature PlsTsat1 in the second use example. [Figure 9] FIG. 9 is a diagram showing an example of a method for searching for the optimum V2 voltage in the second use example. [Figure 10] FIG. 10 is a diagram showing an example of a method for detecting an abnormality in the device temperature sensor 36 in the third use example. [Figure 11] FIG. 11 is a diagram showing an example of determination by the control device 50 according to the state of each device temperature in a modified example of the third use example. [Figure 12] FIG. 12 is a diagram showing an example of a method for detecting an abnormality in a water temperature sensor in a modified example of the third use example. [Figure 13] FIG. 13 is a diagram illustrating an example of a vehicle control method in the fourth usage example. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the following embodiment is an example in which the moving body of the present invention is a vehicle. Furthermore, in the following, identical or similar elements will be given identical or similar reference numerals, and their description may be omitted or simplified as appropriate.

[0014] [1. Vehicle outline] Fig. 1 is a diagram showing an example of a schematic configuration of a vehicle 1 according to this embodiment. The vehicle 1 according to this embodiment shown in Fig. 1 is a hybrid electric vehicle, and includes a battery BAT, an engine ENG, a first motor generator MG1, a second motor generator MG2, a power conversion device 10, a cooling device 20, a vehicle sensor 30, and a control device 50.

[0015] The battery BAT is a secondary battery that can be charged and discharged. For example, the battery BAT has a plurality of storage cells connected in series or series-parallel, and is configured to be able to output a high voltage of 100 to 400 V. For example, lithium ion batteries or nickel-metal hydride batteries can be used as the storage cells of the battery BAT.

[0016] The engine ENG is an internal combustion engine that outputs power generated by burning fuel such as gasoline, diesel, or ethanol-blended fuel. The engine ENG is mechanically coupled to a second motor generator MG2 (described later) and may also be mechanically coupled to the drive wheels DW of the vehicle 1 via a clutch CL. The clutch CL may be, for example, a friction clutch. The power output from the engine ENG is transmitted to the second motor generator MG2 and the drive wheels DW when the clutch CL is in an engaged state (in other words, an engaged state), and is transmitted only to the second motor generator MG2 when the clutch CL is in a disengaged state (in other words, an open state).

[0017] The first motor generator MG1 is a motor generator (a so-called "traction motor") that is mechanically coupled to the drive wheels DW and is used as a drive source for the vehicle 1. As the first motor generator MG1, for example, an AC motor (more specifically, a three-phase AC motor) can be used.

[0018] The first motor generator MG1 is also electrically connected to the battery BAT and the second motor generator MG2 via a power conversion device 10, which will be described later. The first motor generator MG1 operates as an electric motor by receiving power from at least one of the battery BAT and the second motor generator MG2, and outputs power. The power output from the first motor generator MG1 is transmitted to the drive wheels DW. In other words, the vehicle 1 travels by transmitting power from at least one of the engine ENG and the first motor generator MG1 to the drive wheels DW.

[0019] Furthermore, the first motor generator MG1 may also perform regenerative operation as a generator to generate electricity (so-called "regenerative power generation") when braking the vehicle 1. The electric power generated by the regenerative operation of the first motor generator MG1 (hereinafter also referred to as "regenerative power") can be supplied to the battery BAT via the power conversion device 10. This allows the battery BAT to be charged by the regenerative power.

[0020] The second motor generator MG2 is mechanically connected to the engine ENG and is used as a generator that generates electricity using the power of the engine ENG. The second motor generator MG2 is also electrically connected to the battery BAT and the first motor generator MG1 via the power conversion device 10. The electric power generated by the second motor generator MG2 is supplied to at least one of the battery BAT and the first motor generator MG1 via the power conversion device 10. This makes it possible to charge the battery BAT and drive the first motor generator MG1 using the electric power generated by the second motor generator MG2.

[0021] The power conversion device 10 is a device (a so-called "power control unit") that converts input power and outputs the converted power. In this embodiment, the power conversion device 10 is electrically connected to each of the first motor generator MG1, the second motor generator MG2, and the battery BAT, and converts the power exchanged among them.

[0022] More specifically, the power conversion device 10 is configured by accommodating, for example, a first inverter 11, a second inverter 12, and a voltage conversion device 13 in a single housing. Here, the first inverter 11 and the second inverter 12 are devices that include a plurality of switching elements and convert DC to AC or AC to DC by switching these elements. As the switching elements of the first inverter 11 and the second inverter 12, for example, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) or IGBTs (Insulated Gate Bipolar Transistors) can be used.

[0023] The voltage conversion device 13 is a device that converts an input voltage into a predetermined voltage and outputs the converted voltage (also referred to as a "voltage control unit"). For example, a DC / DC converter can be used as the voltage conversion device 13. In this embodiment, the voltage conversion device 13 converts the voltage of the power exchanged between the first motor generator MG1 or the second motor generator MG2 and the battery BAT.

[0024] For example, in vehicle 1, when power from battery BAT is supplied to first motor generator MG1, the output voltage of battery BAT is boosted by voltage conversion device 13, then converted to AC power by first inverter 11, and the AC power is supplied to first motor generator MG1.

[0025] In addition, in vehicle 1, when regenerative power is generated by first motor generator MG1, the AC power as regenerative power generated by first motor generator MG1 is converted to DC power by first inverter 11, and then the DC power is reduced in voltage by voltage conversion device 13, and the reduced DC power is supplied to battery BAT.

[0026] Furthermore, in vehicle 1, when power is generated by second motor generator MG2, the AC power generated by second motor generator MG2 is converted into DC power by second inverter 12 and then supplied to first motor generator MG1 via first inverter 11 or to battery BAT via voltage converter 13. In this case, first inverter 11 converts the DC power received from second inverter 12 into AC power and outputs it to first motor generator MG1. Furthermore, voltage converter 13 steps down the DC power received from second inverter 12 and outputs the stepped-down DC power to battery BAT.

[0027] The cooling device 20 is a device that cools the power conversion device 10. For example, the cooling device 20 is a water-cooled cooling device that includes a cooling circuit 21 in which cooling water (e.g., LLC (Long Life Coolant)) circulates as a refrigerant, and an electric pump 22 that pumps the cooling water in the cooling circuit 21.

[0028] The cooling circuit 21 exchanges heat between the cooling water and the power conversion device 10 (for example, a housing that houses the first inverter 11, the second inverter 12, and the voltage conversion device 13), and also exchanges heat between the cooling water and the outside air. The cooling circuit 21 can be realized by, for example, a water jacket or a radiator provided in the housing of the power conversion device 10.

[0029] The electric pump 22 is an electric pump driven by power from the battery BAT or power generated by the second motor generator MG2, and is controlled, for example, by a control device 50 (described later). The control device 50 controls the electric pump 22 using, for example, PWM (Pulse Width Modulation) control.

[0030] The vehicle sensor 30 is a sensor that acquires various information related to the vehicle 1 and outputs the acquired information to the control device 50 described below. The information acquired by the vehicle sensor 30 is used for the control of the vehicle 1 by the control device 50 (hereinafter also simply referred to as "vehicle control").

[0031] The vehicle sensors 30 include, for example, a first current / voltage sensor 31, a second current / voltage sensor 32, an MOT rotation speed sensor 33, a GEN rotation speed sensor 34, a water temperature sensor 35, and a device temperature sensor 36.

[0032] The first current / voltage sensor 31 is a sensor that detects the current value (hereinafter also referred to as "I1 current") and voltage value (hereinafter also referred to as "V1 voltage") of the power exchanged between the battery BAT and the voltage conversion device 13. The first current / voltage sensor 31 can be realized, for example, by a current sensor and a voltage sensor provided on the power line connecting the battery BAT and the voltage conversion device 13.

[0033] The second current / voltage sensor 32 is a sensor that detects the current value (hereinafter also referred to as "I2 current") and voltage value (hereinafter also referred to as "V2 voltage") of the power exchanged between the voltage conversion device 13 and the first inverter 11 and / or the second inverter 12. The second current / voltage sensor 32 can be realized, for example, by a current sensor and a voltage sensor provided on the power lines connecting the voltage conversion device 13 to the first inverter 11 and the second inverter 12.

[0034] The MOT rotation speed sensor 33 is a sensor that detects the rotation speed of the first motor generator MG1 (hereinafter also referred to as "MOT rotation speed"). For example, the MOT rotation speed sensor 33 can be realized by a resolver provided in the first motor generator MG1.

[0035] The GEN rotation speed sensor 34 is a sensor that detects the rotation speed of the second motor generator MG2 (hereinafter also referred to as "GEN rotation speed"). For example, the GEN rotation speed sensor 34 can be realized by a resolver provided in the second motor generator MG2.

[0036] The water temperature sensor 35 is a sensor that detects the temperature of the cooling water (hereinafter also referred to as “water temperature TW”) circulating through the cooling circuit 21. For example, the water temperature sensor 35 can be realized by a temperature sensor provided in the cooling circuit 21.

[0037] The device temperature sensor 36 is a sensor that detects the temperature (hereinafter also referred to as "device temperature Tj") of the power conversion device 10. For example, the device temperature sensor 36 can be realized by a temperature sensor provided on a semiconductor chip on which switching elements of the power conversion device 10 are integrated.

[0038] Furthermore, although illustrations and detailed explanations are omitted, the vehicle sensor 30 may include, for example, a vehicle speed sensor that detects the traveling speed of the vehicle 1 (hereinafter also referred to as "vehicle speed"), an AP sensor that detects the amount of operation of the accelerator pedal of the vehicle 1 (hereinafter also referred to as "AP (accelerator position)"), etc.

[0039] The control device 50 is a computer that performs overall control of the vehicle 1, and is configured to include, for example, a processor 50a that performs various calculations, a storage unit 50b that has a non-transitory storage medium (for example, a ROM (Read Only Memory), a RAM (Random Access Memory), or a flash memory) that stores various information, and an I / F (interface) unit 50c that controls input and output of data between the inside and outside of the control device 50. For example, the control device 50 can be realized by one ECU (Electronic Control Unit) or by multiple ECUs working together.

[0040] The control device 50 controls, for example, the output of the engine ENG based on information acquired by the vehicle sensor 30, controls the output of the first motor generator MG1 and / or the second motor generator MG2 via the power conversion device 10, controls the state of the clutch CL, and controls the electric pump 22.

[0041] As an example, the control device 50 controls the driving mode of the vehicle 1. Here, the driving mode of the vehicle 1 may include, for example, an EV (Electric Vehicle) driving mode, a hybrid driving mode, and an engine driving mode.

[0042] The EV driving mode is a driving mode in which only the electric power of the battery BAT is supplied to the first motor generator MG1, and the first motor generator MG1 outputs power corresponding to that electric power to drive the vehicle 1. More specifically, in the EV driving mode, the control device 50 disengages the clutch CL and stops the engine ENG (i.e., the second motor generator MG2), and supplies only the electric power of the battery BAT to the first motor generator MG1 to drive the first motor generator MG1 and drive the vehicle 1.

[0043] The hybrid driving mode is a driving mode in which electric power generated by at least the second motor generator MG2 is supplied to the first motor generator MG1, and the vehicle 1 is driven mainly by power output by the first motor generator MG1 in response to that electric power. More specifically, in the hybrid driving mode, the control device 50 disengages the clutch CL and causes the second motor generator MG2 to generate electric power using the power of the engine ENG. The control device 50 then supplies the electric power generated by the second motor generator MG2 to the first motor generator MG1 to drive the first motor generator MG1 and drive the vehicle 1. Note that in the hybrid driving mode, the control device 50 may also supply electric power from the battery BAT to the first motor generator MG1 as appropriate.

[0044] The engine running mode is a running mode in which the vehicle 1 is run mainly by the power output by the engine ENG. More specifically, in the engine running mode, the control device 50 operates the engine ENG with the clutch CL in an engaged state. Note that in the engine running mode, the control device 50 may supply electric power from the battery BAT to the first motor generator MG1 as appropriate, and run the vehicle 1 also using the power output by the first motor generator MG1.

[0045] As another example, the control device 50 derives a saturation temperature Tsat and a loss at saturation temperature PlsTsat, which will be described later, and controls the vehicle 1 based on the saturation temperature Tsat and / or the loss at saturation temperature PlsTsat. A specific example of the control performed by the control device 50 in this case will be described in detail below.

[0046] [2. Functional configuration of the control device] Fig. 2 is a block diagram showing an example of the functional configuration of the control device 50. As shown in Fig. 2, the control device 50 includes, for example, a loss characteristic deriving unit 51, a flow rate deriving unit 52, a thermal resistance deriving unit 53, a thermal resistance characteristic deriving unit 54, a saturation temperature / loss at saturation temperature deriving unit 55, and a vehicle control unit 56. Each of the functional units of the loss characteristic deriving unit 51, the flow rate deriving unit 52, the thermal resistance deriving unit 53, the thermal resistance characteristic deriving unit 54, the saturation temperature / loss at saturation temperature deriving unit 55, and the vehicle control unit 56 can be realized, for example, by the processor 50a executing a program stored in the storage unit 50b or by the I / F unit 50c.

[0047] Based on the operating conditions of the first motor generator MG1, the loss characteristic derivation unit 51 derives the loss characteristic Lc representing the loss for each temperature (i.e., device temperature Tj) of the power conversion device 10 when the first motor generator MG1 is operated under those operating conditions, and passes the processing results to the thermal resistance characteristic derivation unit 54 and the saturation temperature / loss at saturation temperature derivation unit 55.

[0048] An example of the loss in the power conversion device 10 is the loss in the first inverter 11 (hereinafter also referred to as "MOT-INV loss"). Another example of the loss in the power conversion device 10 is the loss in the second inverter 12 (hereinafter also referred to as "GEN-INV loss"). Furthermore, another example of the loss in the power conversion device 10 is the loss in the voltage conversion device 13 (hereinafter also referred to as "VCU (Voltage Control Unit) loss"). That is, the loss in the power conversion device 10 may include the MOT-INV loss, the GEN-INV loss, and the VCU loss.

[0049] Furthermore, the operating conditions of the first motor generator MG1 may include the MOT rotation speed, the output torque of the first motor generator MG1 (hereinafter also referred to as "MOT torque"), and the V2 voltage.

[0050] For example, information indicating the current MOT rotation speed, MOT torque, and V2 voltage is input to the loss characteristic derivation unit 51. Note that the control device 50 can, for example, obtain information indicating the current MOT rotation speed from the MOT rotation speed sensor 33 and information indicating the current V2 voltage from the second current / voltage sensor 32, and can derive (i.e., obtain) information indicating the current MOT torque based on the current MOT rotation speed and V2 voltage. The loss characteristic derivation unit 51 then derives the loss characteristic Lc when the first motor generator MG1 is operated at the current MOT rotation speed, MOT torque, and V2 voltage.

[0051] More specifically, for example, the storage unit 50b stores in advance a loss map Mp1, which is information indicating losses in the power conversion device 10 corresponding to each combination of the MOT rotation speed, MOT torque, V2 voltage, and device temperature Tj. Here, the loss map Mp1 may be any information that can identify the losses in the power conversion device 10 from the MOT rotation speed, MOT torque, V2 voltage, and device temperature Tj, and may be configured as a group of multiple maps (in other words, tables) in terms of data. When the loss map Mp1 is configured as a group of multiple maps, the loss map Mp1 may include, for example, a map indicating losses in the power conversion device 10 corresponding to combinations of the MOT rotation speed, MOT torque, and V2 voltage at a first temperature T1 (described later), and a map indicating losses in the power conversion device 10 corresponding to combinations of the MOT rotation speed, MOT torque, and V2 voltage at a second temperature T2 (described later).

[0052] 2, the loss characteristics derivation unit 51 derives, with reference to the loss map Mp1, a first-temperature loss PlsT1, which is a loss of the power conversion device 10 when the device temperature Tj is set to a predetermined first temperature T1 at the current MOT rotation speed, MOT torque, and V2 voltage (in other words, the current operating conditions of the first motor generator MG1). In this case, the loss characteristics derivation unit 51 derives, as the first-temperature loss PlsT1, a loss corresponding to a combination of the current MOT rotation speed, MOT torque, and V2 voltage and the first temperature T1 as the device temperature Tj, from the loss map Mp1. Note that the first temperature T1 is a temperature determined in advance by the manufacturer of the vehicle 1 or the like, and may be, for example, 25°C, which is one of the temperatures that the device temperature Tj can assume when the vehicle 1 is running.

[0053] 2, the loss characteristics deriving unit 51 also derives the second-temperature loss PlsT2, which is the loss of the power conversion device 10 when the current MOT rotation speed, MOT torque, and V2 voltage are used and the device temperature Tj is set to a predetermined second temperature T2, in the same manner as the first-temperature loss PlsT1. That is, the loss characteristics deriving unit 51 derives, in the loss map Mp1, the loss corresponding to the combination of the current MOT rotation speed, MOT torque, and V2 voltage and the second temperature T2 as the device temperature Tj, as the second-temperature loss PlsT2. Note that the second temperature T2 is a temperature determined in advance by the manufacturer of the vehicle 1 or the like and is different from the first temperature T1. For example, the second temperature T2 can be 175°C, which is one of the temperatures that the device temperature Tj can assume when the vehicle 1 is running and is higher than the first temperature T1 (e.g., 25°C).

[0054] The loss characteristic deriving unit 51 then derives the loss characteristic Lc based on the loss at the first temperature PlsT1 and the loss at the second temperature PlsT2. The loss characteristic Lc can be geometrically determined from the loss at the first temperature PlsT1 and the loss at the second temperature PlsT2, for example. More specifically, as shown in a box marked with reference numeral 51c in FIG. 2, the loss characteristic deriving unit 51 may derive, as the loss characteristic Lc, a line segment passing through coordinate points P1 (PlsT1, T1) and P2 (PlsT2, T2) on a plane having the loss of the power conversion device 10 on the horizontal axis and the device temperature Tj on the vertical axis.

[0055] Here, the loss characteristic deriving unit 51 is configured to derive the loss characteristic Lc based on two losses, the loss at the first temperature PlsT1 and the loss at the second temperature PlsT2, which correspond to different device temperatures Tj, but this is not limiting. For example, the loss characteristic deriving unit 51 may derive the loss characteristic Lc based on three or more losses corresponding to different device temperatures Tj.

[0056] In addition, although the loss characteristic deriving unit 51 is configured to derive the loss characteristic Lc based on the current operating conditions of the first motor generator MG1, this is not limiting. For example, as will be described later, the loss characteristic deriving unit 51 may derive the loss characteristic Lc when the first motor generator MG1 is operated under a predetermined operating condition (for example, a predetermined V2 voltage).

[0057] The flow rate derivation unit 52 derives the flow rate Fw of the coolant pumped per unit time by the electric pump 22 based on the water temperature TW (i.e., the temperature of the coolant) detected by the water temperature sensor 35 and the driving state of the electric pump 22, and passes the processing result to the thermal resistance derivation unit 53. The driving state of the electric pump 22 can be, for example, the duty of the electric pump 22, which is PWM controlled (hereinafter simply referred to as "duty"). The flow rate Fw is an example of a cooling condition for the power conversion device 10 by the cooling device 20.

[0058] For example, the flow rate derivation unit 52 receives input of information indicating the current water temperature TW (hereinafter also referred to as "water temperature TWnow") and a duty cycle that indicates the current driving state of the electric pump 22. Then, the flow rate derivation unit 52 derives the current flow rate Fw based on the water temperature TWnow and the current duty cycle.

[0059] More specifically, for example, the memory unit 50b stores in advance a flow rate map Mp2, which is information indicating the flow rate Fw corresponding to each combination of duty and water temperature TW. As shown in the box marked with reference numeral 52a in Fig. 2, the flow rate derivation unit 52 derives the flow rate Fw corresponding to the combination of the current water temperature TW (i.e., water temperature TWnow) and duty, by referring to the flow rate map Mp2. In the example shown in Fig. 2, since the current duty is X [%], Fw1 corresponding to the combination of water temperature TWnow and duty X [%] is derived as the flow rate Fw.

[0060] Although the flow rate derivation unit 52 is configured to derive the flow rate Fw based on the current duty here, this is not limiting. For example, as will be described later, the flow rate derivation unit 52 may be configured to derive the flow rate Fw when the electric pump 22 is driven with a predetermined duty.

[0061] The thermal resistance derivation unit 53 derives the thermal resistance Rt of the power conversion device 10 when the power conversion device 10 is cooled under the cooling conditions of the cooling device 20, based on the cooling conditions of the power conversion device 10, and passes the processing result to the thermal resistance characteristic derivation unit 54.

[0062] For example, the thermal resistance derivation unit 53 derives the thermal resistance Rt based on the flow rate Fw derived by the flow rate derivation unit 52. More specifically, for example, a thermal resistance map Mp3, which is information indicating the thermal resistance Rt corresponding to each flow rate Fw, is stored in advance in the storage unit 50b. Then, as shown in the box marked with reference numeral 53a in Fig. 2, for example, when the flow rate Fw derived by the flow rate derivation unit 52 is Fw1, the thermal resistance derivation unit 53 derives Rt1 corresponding to Fw1 as the thermal resistance Rt.

[0063] Here, the thermal resistance derivation unit 53 derives the thermal resistance Rt based on the flow rate Fw derived by the flow rate derivation unit 52, but this is not limited to this. For example, if the vehicle 1 is equipped with a flow rate sensor capable of detecting the flow rate Fw, the thermal resistance derivation unit 53 may derive the thermal resistance Rt based on the flow rate Fw detected by this flow rate sensor. In this case, the control device 50 does not need to be equipped with the flow rate derivation unit 52.

[0064] The thermal resistance characteristic derivation unit 54 derives a thermal resistance characteristic Rc representing the temperature reached for each loss in the power conversion device 10 based on the loss characteristic Lc derived by the loss characteristic derivation unit 51 and the thermal resistance Rt derived by the thermal resistance derivation unit 53, and passes the processing result to the saturation temperature / loss at saturation temperature derivation unit 55.

[0065] For example, assume that a loss characteristic Lc including a loss at a first temperature PlsT1 and a loss at a second temperature PlsT2 is derived, and that the thermal resistance Rt is derived as Rt1. In this case, as shown in a box marked with reference numeral 54a in FIG. 2, the thermal resistance characteristic derivation unit 54 derives a first ultimate temperature T11, which is the ultimate temperature of the power conversion device 10, using, for example, the following equation (1). Furthermore, the thermal resistance characteristic derivation unit 54 also derives a second ultimate temperature T12, which is the ultimate temperature of the power conversion device 10, using, for example, the following equation (1), when the loss at the power conversion device 10 is the loss at a second temperature PlsT2 and the thermal resistance Rt is Rt1. Note that "TW0" in the following equation (1) may be, for example, the water temperature TWnow.

[0066] Reached temperature of power conversion device 10 = Thermal resistance Rt × Loss of power conversion device 10 + TW0 (1)

[0067] The thermal resistance characteristic derivation unit 54 then derives the thermal resistance characteristic Rc based on the first ultimate temperature T11 and the second ultimate temperature T12. The thermal resistance characteristic Rc can be geometrically determined from the first ultimate temperature T11 and the second ultimate temperature T12. More specifically, as shown in a box marked with reference numeral 54a in FIG. 2, the thermal resistance characteristic derivation unit 54 may derive, as the thermal resistance characteristic Rc, a line segment passing through coordinate points P11 (PlsT1, T11) and P12 (PlsT2, T12) on a plane having the loss of the power conversion device 10 on the horizontal axis and the device temperature Tj on the vertical axis.

[0068] The saturation temperature / loss at saturation temperature derivation unit 55 derives the saturation temperature Tsat and the loss at saturation temperature PlsTsat based on the loss characteristic Lc derived by the loss characteristic derivation unit 51 and the thermal resistance characteristic Rc derived by the thermal resistance characteristic derivation unit 54.

[0069] Here, the saturation temperature Tsat is the temperature that the power conversion device 10 reaches when the first motor generator MG1 is operated under predetermined operating conditions and the power conversion device 10 is cooled under predetermined cooling conditions. For example, in the example shown in Fig. 2, the saturation temperature Tsat is the temperature that the power conversion device 10 reaches when the first motor generator MG1 is operated under the current operating conditions and the power conversion device 10 is cooled under the current cooling conditions. Furthermore, the loss at saturation temperature PlsTsat is the loss of the power conversion device 10 when the device temperature Tj is the saturation temperature Tsat.

[0070] The saturation temperature Tsat and the loss at saturation temperature PlsTsat can be geometrically calculated from the loss characteristic Lc and the thermal resistance characteristic Rc. More specifically, as shown in the box marked with reference numeral 55a in FIG. 2, the saturation temperature / loss at saturation temperature derivation unit 55 derives the loss of the power conversion device 10 corresponding to the intersection point CP between the loss characteristic Lc and the thermal resistance characteristic Rc on a plane with the loss of the power conversion device 10 on the horizontal axis and the device temperature Tj on the vertical axis as the loss at saturation temperature PlsTsat, and derives the device temperature Tj corresponding to the intersection point CP as the saturation temperature Tsat. In other words, the saturation temperature Tsat can be referred to as the device temperature Tj at which the loss (i.e., heat generation) of the power conversion device 10 is balanced with the thermal resistance Rt, and can also be referred to as the device temperature Tj at which the temperature rise of the power conversion device 10 due to the loss of the power conversion device 10 stops.

[0071] In this way, the control device 50 derives the loss of the power conversion device 10 corresponding to the intersection CP of the loss characteristic Lc and the thermal resistance characteristic Rc as the loss at saturation temperature PlsTsat, and derives the device temperature Tj corresponding to the intersection CP as the saturation temperature Tsat, thereby making it possible to accurately determine the saturation temperature Tsat and the loss at saturation temperature PlsTsat through simple calculations.In addition, the control device 50 can also predict the saturation temperature Tsat and the loss at saturation temperature PlsTsat before the actual device temperature Tj reaches the saturation temperature Tsat.

[0072] The vehicle control unit 56 reflects the saturation temperature Tsat and / or the loss at saturation temperature PlsTsat derived by the saturation temperature / loss at saturation temperature derivation unit 55 in vehicle control, and the vehicle control is not particularly limited. For example, the vehicle control unit 56 may control the electric pump 22 or the power conversion device 10 based on the saturation temperature Tsat and / or the loss at saturation temperature PlsTsat. The vehicle control unit 56 may also determine the state of the vehicle 1 (e.g., the presence or absence of an abnormality or the load state) based on the saturation temperature Tsat and / or the loss at saturation temperature PlsTsat. Specific examples of vehicle control based on the saturation temperature Tsat and / or the loss at saturation temperature PlsTsat will be described later as first to fourth application examples of the present invention, and therefore will not be described here. The vehicle control unit 56 is an example of a mobile object control unit in the present invention.

[0073] [3. Processing performed by the control unit] Next, an example of processing executed by the control device 50 will be described. Fig. 3 is a flowchart showing an example of processing executed by the control device 50. For example, while the vehicle 1 is starting up (for example, when the ignition power is on), the control device 50 executes a series of processing shown in Fig. 3 at a predetermined cycle (for example, every 1 [s]).

[0074] 3, first, the control device 50 acquires information indicating, for example, the current MOT rotation speed, MOT torque, V2 voltage, water temperature TW (i.e., water temperature TWnow), and duty of the electric pump 22 (step Sp1). In addition, in the processing of step Sp1, the control device 50 may also acquire information indicating the I1 current and the V1 voltage as needed.

[0075] Next, the control device 50 derives the first temperature loss PlsT1 and the second temperature loss PlsT2 based on the MOT rotation speed, MOT torque, and V2 voltage acquired by the processing of step Sp1, by referring to the loss map Mp1 (step Sp2).

[0076] Next, the control device 50 derives the loss characteristic Lc of the power conversion device 10 based on the loss at the first temperature PlsT1 and the loss at the second temperature PlsT2 derived by the processing of step Sp2 (step Sp3).

[0077] Next, the control device 50 derives the current flow rate Fw by referring to the flow rate map Mp2 based on the water temperature TWnow and Duty acquired by the processing of step Sp1 (step Sp4).

[0078] Next, the control device 50 derives the thermal resistance Rt of the power conversion device 10 based on the flow rate Fw derived by the processing of step Sp4, with reference to the thermal resistance map Mp3 (step Sp5).

[0079] Next, the control device 50 derives the thermal resistance characteristic Rc of the power conversion device 10 based on the loss at the first temperature PlsT1 and the loss at the second temperature PlsT2 derived by the processing of step Sp2 and the thermal resistance Rt derived by the processing of step Sp5 (step Sp6).

[0080] Next, the control device 50 derives the saturation temperature Tsat and the loss at saturation temperature PlsTsat based on the loss characteristic Lc derived by the processing in step Sp3 and the thermal resistance characteristic Rc derived by the processing in step Sp6 (step Sp7).

[0081] Then, the control device 50 controls the vehicle 1 based on the saturation temperature Tsat and / or the loss at saturation temperature PlsTsat derived by the processing in step Sp7 (step Sp8), and ends the series of processing shown in FIG.

[0082] As described above, the control device 50 can derive the saturation temperature Tsat and the loss at saturation temperature PlsTsat when the first motor generator MG1 is operated under the current operating conditions and the power conversion device 10 is cooled under the current cooling conditions, thereby making it possible to perform vehicle control taking into account the saturation temperature Tsat and / or the loss at saturation temperature PlsTsat, which in turn can contribute to improving the energy efficiency of the vehicle 1.

[0083] Furthermore, the control device 50 derives the loss characteristics Lc based on the operating conditions of the first motor generator MG1, such as the MOT rotation speed and MOT torque, and the V2 voltage, which is the voltage value of the power exchanged between the first motor generator MG1 and the power conversion device 10. This makes it possible to derive the loss characteristics Lc taking into account the MOT rotation speed, MOT torque, and V2 voltage.

[0084] Furthermore, the control device 50 derives the flow rate Fw as a cooling condition for the power conversion device 10 based on the water temperature TW detected by the water temperature sensor 35 and the driving state (e.g., duty) of the electric pump 22, and derives the thermal resistance Rt based on the derived flow rate Fw. This makes it possible to appropriately derive the thermal resistance Rt without providing a flow rate sensor that detects the flow rate Fw of the cooling water pumped by the electric pump 22.

[0085] In the example described above, the operating conditions of the first motor generator MG1 used by the control device 50 to derive the saturation temperature Tsat and the loss at saturation temperature PlsTsat are the current operating conditions, but this is not limiting. For example, the control device 50 may derive the saturation temperature Tsat and the loss at saturation temperature PlsTsat using any operating condition (e.g., a predetermined V2 voltage) instead of the current operating condition (e.g., the current V2 voltage) of the first motor generator MG1. This makes it possible to derive the saturation temperature Tsat and the loss at saturation temperature PlsTsat when, for example, the first motor generator MG1 is operated under any operating condition and the power conversion device 10 is cooled under the current cooling condition.

[0086] In the example described above, the cooling conditions of the power conversion device 10 used by the control device 50 to derive the saturation temperature Tsat and the loss at saturation temperature PlsTsat are the current cooling conditions, but this is not limiting. For example, the control device 50 may derive the saturation temperature Tsat and the loss at saturation temperature PlsTsat using any cooling condition (e.g., a predetermined duty) instead of the current cooling condition of the power conversion device 10 (e.g., the current duty of the electric pump 22). This makes it possible to derive the saturation temperature Tsat and the loss at saturation temperature PlsTsat when, for example, the first motor generator MG1 is operated under the current operating condition and the power conversion device 10 is cooled under any cooling condition.

[0087] In the example described above, the control device 50 derives the saturation temperature Tsat and the loss at saturation temperature PlsTsat based on the operating conditions of the first motor-generator MG1. However, this is not limiting. For example, the control device 50 may derive the saturation temperature Tsat and the loss at saturation temperature PlsTsat based on the operating conditions of the second motor-generator MG2, instead of or in addition to the saturation temperature Tsat and the loss at saturation temperature PlsTsat based on the operating conditions of the first motor-generator MG1. The operating conditions of the second motor-generator MG2 may include, for example, the GEN rotation speed, the output torque of the second motor-generator MG2 (hereinafter also referred to as "GEN torque"), the V2 voltage, and the like. In this case, the control device 50 may obtain, for example, information indicating the GEN rotation speed from the GEN rotation speed sensor 34 and information indicating the V2 voltage from the second current / voltage sensor 32, and may derive information indicating the GEN torque based on the GEN rotation speed and the V2 voltage.

[0088] Furthermore, the control device 50 may also derive the saturation temperature Tsat and the loss at saturation temperature PlsTsat based on the operating conditions of the voltage conversion device 13. The operating conditions of the voltage conversion device 13 may include, for example, the I1 current, the V1 voltage, the V2 voltage, etc. In this case, the control device 50 may obtain, for example, information indicating the I1 current and the V1 voltage from the first current / voltage sensor 31 and information indicating the V2 voltage from the second current / voltage sensor 32.

[0089] [4. 1st usage example] Next, a first application example of the present invention will be described. This first application example is an example in which the control device 50 controls the electric pump 22 based on the loss at saturation temperature PlsTsat. In this first application example, the control device 50 derives a first saturation temperature Tsat1, a second saturation temperature Tsat2, and a third saturation temperature Tsat3 as the saturation temperature Tsat, and derives a first saturation temperature loss PlsTsat1, a second saturation temperature loss PlsTsat2, and a third saturation temperature loss PlsTsat3 as the loss at saturation temperature PlsTsat.

[0090] Here, the first saturation temperature Tsat1 is the saturation temperature Tsat based on the MOT-INV loss (i.e., the operating conditions of the first motor-generator MG1). The first saturation temperature loss PlsTsat1 is the saturation temperature loss PlsTsat based on the MOT-INV loss. A specific example of how to derive the first saturation temperature Tsat1 and the first saturation temperature loss PlsTsat1 will be described later with reference to FIG. 4 etc.

[0091] The second saturation temperature Tsat2 is the saturation temperature Tsat based on the GEN-INV loss (i.e., the operating conditions of the second motor generator MG2). The second saturation temperature loss PlsTsat2 is the saturation temperature loss PlsTsat based on the GEN-INV loss. A specific example of how to derive the second saturation temperature Tsat2 and the second saturation temperature loss PlsTsat2 will be described later using FIG. 5 etc.

[0092] The third saturation temperature Tsat3 is the saturation temperature Tsat based on the VCU loss (i.e., the operating conditions of the voltage conversion device 13). The third saturation temperature loss PlsTsat3 is the saturation temperature loss PlsTsat based on the VCU loss. A specific example of derivation of the third saturation temperature Tsat3 and the third saturation temperature loss PlsTsat3 will be described later with reference to FIG. 6 etc.

[0093] That is, in the first usage example, the control device 50 derives the saturation temperature Tsat and the loss at saturation temperature PlsTsat for each of the motor generators, such as the first motor generator MG1 and the second motor generator MG2, provided in the vehicle 1. This makes it possible to perform vehicle control taking into account the saturation temperature Tsat and / or the loss at saturation temperature PlsTsat corresponding to each motor generator, even if the vehicle 1 is provided with multiple motor generators.

[0094] (4-1. Method of deriving the first saturation temperature and loss at the first saturation temperature in the first application example) First, a method for deriving the first saturation temperature Tsat1 and the loss at first saturation temperature PlsTsat1 in the first application example will be described. Fig. 4 is a diagram showing an example of a method for deriving the first saturation temperature Tsat1 and the loss at first saturation temperature PlsTsat1 in the first application example.

[0095] In the first use example, the control device 50 (for example, the loss characteristics derivation unit 51) derives, for example, a first temperature loss PlsT1a, which is the MOT-INV loss when the current MOT rotation speed, MOT torque, and V2 voltage and the device temperature Tj are set to 25°C, by referring to a loss map Mp1a, as shown in a box marked with reference numeral 401 in Fig. 4. Here, the loss map Mp1a is information indicating the MOT-INV loss corresponding to each combination of the MOT rotation speed, MOT torque, V2 voltage, and device temperature Tj, and is stored in advance in, for example, the storage unit 50b. Note that the loss map Mp1a only needs to be information that can identify the MOT-INV loss from the MOT rotation speed, MOT torque, V2 voltage, and device temperature Tj, and, like the loss map Mp1, may be configured as a group of multiple maps in terms of data.

[0096] 4, the control device 50 also derives the second temperature loss PlsT2a and the third temperature loss PlsT3a in the same manner as the first temperature loss PlsT1a. Here, the second temperature loss PlsT2a can be, for example, the MOT-INV loss when the device temperature Tj is set to 75°C with the current MOT rotation speed, MOT torque, and V2 voltage. The third temperature loss PlsT3a can be, for example, the MOT-INV loss when the device temperature Tj is set to 175°C with the current MOT rotation speed, MOT torque, and V2 voltage.

[0097] Next, the control device 50 (for example, the loss characteristic deriving unit 51) derives an MOT-INV loss characteristic Lc1 that represents the MOT-INV loss for each device temperature Tj based on the first temperature loss PlsT1a, the second temperature loss PlsT2a, and the third temperature loss PlsT3a, as shown in the box marked with reference numeral 402 in Fig. 4. The MOT-INV loss characteristic Lc1 is an example of the loss characteristic Lc, and like the loss characteristic Lc, can be geometrically determined from, for example, the first temperature loss PlsT1a, the second temperature loss PlsT2a, and the third temperature loss PlsT3a.

[0098] Next, the control device 50 (e.g., the flow rate derivation unit 52) ​​derives a flow rate Fw corresponding to the water temperature TWnow for each duty of the electric pump 22 by referring to a flow rate map Mp2, as shown in a box marked with reference numeral 403 in Fig. 4. For example, as shown in Fig. 4, the control device 50 derives a flow rate Fw for each of the cases where the duty of the electric pump 22 is 40[%], 60[%], and 80[%]. In the example shown in Fig. 4, Fw1 is derived as the flow rate Fw when the duty of the electric pump 22 is 40[%], Fw2 is derived as the flow rate Fw when the duty is 60[%], and Fw3 is derived as the flow rate Fw when the duty is 80[%].

[0099] Next, the control device 50 (for example, the thermal resistance derivation unit 53) derives the thermal resistance Rt corresponding to each flow rate Fw based on each flow rate Fw derived by the above process, with reference to a thermal resistance map Mp3, as shown in the box marked with reference numeral 404 in Fig. 4. In the example shown in Fig. 4, when the flow rate Fw is Fw1 (in other words, when the duty is 40[%]), Rt1 is derived as the thermal resistance Rt, when the flow rate Fw is Fw2 (in other words, when the duty is 60[%]), Rt2 is derived as the thermal resistance Rt, and when the flow rate Fw is Fw3 (in other words, when the duty is 80[%]), Rt3 is derived as the thermal resistance Rt.

[0100] Next, the control device 50 (e.g., the thermal resistance characteristic derivation unit 54) derives a thermal resistance characteristic Rc corresponding to each thermal resistance Rt based on each thermal resistance Rt derived by the above process, as shown in the box marked with reference numeral 405 in Fig. 4. In the example shown in Fig. 4, when the thermal resistance Rt is Rt1 (in other words, when the duty is 40[%]), a thermal resistance characteristic Rc1a is derived as the thermal resistance characteristic Rc. When the thermal resistance Rt is Rt2 (in other words, when the duty is 60[%]), a thermal resistance characteristic Rc2a is derived as the thermal resistance characteristic Rc. When the thermal resistance Rt is Rt3a (in other words, when the duty is 80[%]), a thermal resistance characteristic Rc3a is derived as the thermal resistance characteristic Rc.

[0101] For example, the thermal resistance characteristic Rc1a can be geometrically calculated from a first ultimate temperature when the loss of the power conversion device 10 is the loss at a first temperature PlsT1a and the thermal resistance Rt is Rt1, a second ultimate temperature when the loss of the power conversion device 10 is the loss at a second temperature PlsT2a and the thermal resistance Rt is Rt1, and a third ultimate temperature when the loss of the power conversion device 10 is the loss at a third temperature PlsT3a and the thermal resistance Rt is Rt1. Each of the first, second, and third ultimate temperatures can be calculated, for example, using the above-mentioned formula (1). The thermal resistance characteristics Rc2a and Rc3a can also be calculated in the same way as the thermal resistance characteristic Rc1a.

[0102] Next, the control device 50 (for example, the saturation temperature / loss at saturation temperature derivation unit 55) derives the first saturation temperature Tsat1 and the loss at first saturation temperature PlsTsat1 for each thermal resistance characteristic Rc based on the MOT-INV loss characteristic Lc1 derived by the above processing and each thermal resistance characteristic Rc, as shown in the box marked with the symbol 406 in Figure 4.

[0103] For example, the first saturation temperature Tsat1 and the loss at first saturation temperature PlsTsat1 based on the MOT-INV loss characteristic Lc1 and the thermal resistance characteristic Rc1a can be found as the intersection of the MOT-INV loss characteristic Lc1 and the thermal resistance characteristic Rc1a on a plane with the loss of the power conversion device 10 (here, the MOT-INV loss) on the horizontal axis and the device temperature Tj on the vertical axis. In the example shown in Fig. 4, TsatA is derived as the first saturation temperature Tsat1 based on the MOT-INV loss characteristic Lc1 and the thermal resistance characteristic Rc1a, and PlsTsatA is derived as the loss at first saturation temperature PlsTsat1 based on the MOT-INV loss characteristic Lc1 and the thermal resistance characteristic Rc1a. In addition, the first saturation temperature Tsat1 and the loss at the first saturation temperature PlsTsat1 based on the MOT-INV loss characteristic Lc1 and the thermal resistance characteristic Rc1a can also be said to be the first saturation temperature Tsat1 and the loss at the first saturation temperature PlsTsat1 when the duty of the electric pump 22 is 40[%].

[0104] Similarly, the control device 50 derives the first saturation temperature Tsat1 and the loss at first saturation temperature PlsTsat1 based on the MOT-INV loss characteristic Lc1 and the thermal resistance characteristic Rc2a, and the first saturation temperature Tsat1 and the loss at first saturation temperature PlsTsat1 based on the MOT-INV loss characteristic Lc1 and the thermal resistance characteristic Rc3a. This allows the control device 50 to obtain the first saturation temperature Tsat1 and the loss at first saturation temperature PlsTsat1 for each thermal resistance characteristic Rc, in other words, for each duty of the electric pump 22.

[0105] (4-2. Method of deriving the second saturation temperature and loss at the second saturation temperature in the first application example) Next, a method for deriving the second saturation temperature Tsat2 and the loss at the second saturation temperature PlsTsat2 in the first application example will be described. Fig. 5 is a diagram showing an example of a method for deriving the second saturation temperature Tsat2 and the loss at the second saturation temperature PlsTsat2 in the first application example.

[0106] In the first use example, the control device 50 (e.g., the loss characteristics derivation unit 51) derives, for example, a first temperature loss PlsT1b, which is the GEN-INV loss when the current GEN rotation speed, GEN torque, and V2 voltage are used and the device temperature Tj is set to 25°C, by referring to a loss map Mp1b, as shown in a box marked with reference numeral 501 in Fig. 5. Here, the loss map Mp1b is information indicating the GEN-INV loss corresponding to each combination of the GEN rotation speed, GEN torque, V2 voltage, and device temperature Tj, and is stored in advance in, for example, the storage unit 50b. Note that the loss map Mp1b only needs to be information that enables the GEN-INV loss to be identified from the GEN rotation speed, GEN torque, V2 voltage, and device temperature Tj, and, like the loss map Mp1, may be configured as a group of multiple maps in terms of data.

[0107] 5, the control device 50 also derives the second temperature loss PlsT2b and the third temperature loss PlsT3b in the same manner as the first temperature loss PlsT1b. Here, the second temperature loss PlsT2b can be, for example, the GEN-INV loss when the current GEN rotation speed, GEN torque, and V2 voltage are used and the device temperature Tj is set to 75°C. The third temperature loss PlsT3b can be, for example, the GEN-INV loss when the current GEN rotation speed, GEN torque, and V2 voltage are used and the device temperature Tj is set to 175°C.

[0108] Next, the control device 50 (for example, the loss characteristic deriving unit 51) derives a GEN-INV loss characteristic Lc2 representing the GEN-INV loss for each device temperature Tj based on the loss at the first temperature PlsT1b, the loss at the second temperature PlsT2b, and the loss at the third temperature PlsT3b, as shown in the box marked with reference numeral 502 in Fig. 5. The GEN-INV loss characteristic Lc2 is another example of the loss characteristic Lc, and like the loss characteristic Lc, can be geometrically determined from, for example, the loss at the first temperature PlsT1b, the loss at the second temperature PlsT2b, and the loss at the third temperature PlsT3b.

[0109] Next, the control device 50 (for example, the flow rate derivation unit 52) ​​derives the flow rate Fw corresponding to the water temperature TWnow for each duty of the electric pump 22 by referring to the flow rate map Mp2, as shown in the box marked with the reference symbol 503 in Fig. 5. In the example shown in Fig. 5, Fw1 is derived as the flow rate Fw when the duty of the electric pump 22 is 40[%], Fw2 is derived as the flow rate Fw when the duty is 60[%], and Fw3 is derived as the flow rate Fw when the duty is 80[%].

[0110] The process shown in the box marked with reference numeral 503 in Fig. 5 is the same as the process shown in the box marked with reference numeral 403 in Fig. 4. Therefore, if the control device 50 has already executed the process shown in the box marked with reference numeral 403 in Fig. 4, the control device 50 may use the processing result of the process shown in the box marked with reference numeral 403 in Fig. 4 as is, without re-executing the process shown in the box marked with reference numeral 503 in Fig. 5.

[0111] Next, the control device 50 (for example, the thermal resistance derivation unit 53) derives the thermal resistance Rt corresponding to each flow rate Fw based on each flow rate Fw derived by the above process, with reference to a thermal resistance map Mp3, as shown in the box marked with reference numeral 504 in Fig. 5. In the example shown in Fig. 5, when the flow rate Fw is Fw1 (in other words, when the duty is 40[%]), Rt1 is derived as the thermal resistance Rt, when the flow rate Fw is Fw2 (in other words, when the duty is 60[%]), Rt2 is derived as the thermal resistance Rt, and when the flow rate Fw is Fw3 (in other words, when the duty is 80[%]), Rt3 is derived as the thermal resistance Rt.

[0112] The process shown in the box marked with reference numeral 504 in Fig. 5 is the same as the process shown in the box marked with reference numeral 404 in Fig. 4. Therefore, if the control device 50 has already executed the process shown in the box marked with reference numeral 404 in Fig. 4, the control device 50 may use the processing result of the process shown in the box marked with reference numeral 404 in Fig. 4 as is, without re-executing the process shown in the box marked with reference numeral 504 in Fig. 5.

[0113] Next, the control device 50 (e.g., the thermal resistance characteristic derivation unit 54) derives a thermal resistance characteristic Rc corresponding to each thermal resistance Rt based on each thermal resistance Rt derived by the above process, as shown in the box marked with reference numeral 505 in Fig. 5. In the example shown in Fig. 5, a thermal resistance characteristic Rc1b is derived as the thermal resistance characteristic Rc when the thermal resistance Rt is Rt1 (in other words, when the duty is 40[%]). Furthermore, a thermal resistance characteristic Rc2b is derived as the thermal resistance characteristic Rc when the thermal resistance Rt is Rt2 (in other words, when the duty is 60[%]). Furthermore, a thermal resistance characteristic Rc3b is derived as the thermal resistance characteristic Rc when the thermal resistance Rt is Rt3a (in other words, when the duty is 80[%]).

[0114] For example, the thermal resistance characteristic Rc1b can be geometrically calculated from a first ultimate temperature when the loss of the power conversion device 10 is the loss at a first temperature PlsT1b and the thermal resistance Rt is Rt1, a second ultimate temperature when the loss of the power conversion device 10 is the loss at a second temperature PlsT2b and the thermal resistance Rt is Rt1, and a third ultimate temperature when the loss of the power conversion device 10 is the loss at a third temperature PlsT3b and the thermal resistance Rt is Rt1. The first, second, and third ultimate temperatures can be calculated, for example, using the above formula (1). The thermal resistance characteristics Rc2b and Rc3b can also be calculated in the same way as the thermal resistance characteristic Rc1b.

[0115] Next, the control device 50 (for example, the saturation temperature / loss at saturation temperature derivation unit 55) derives the second saturation temperature Tsat2 and the loss at second saturation temperature PlsTsat2 for each thermal resistance characteristic Rc based on the GEN-INV loss characteristic Lc2 derived by the above processing and each thermal resistance characteristic Rc, as shown in the box marked with the symbol 506 in Figure 5.

[0116] For example, the second saturation temperature Tsat2 and the loss at second saturation temperature PlsTsat2 based on the GEN-INV loss characteristic Lc2 and the thermal resistance characteristic Rc1b can be found as the intersection of the GEN-INV loss characteristic Lc2 and the thermal resistance characteristic Rc1b on a plane with the loss of the power conversion device 10 (the GEN-INV loss here) on the horizontal axis and the device temperature Tj on the vertical axis. In the example shown in Fig. 5, TsatB is derived as the second saturation temperature Tsat2 based on the GEN-INV loss characteristic Lc2 and the thermal resistance characteristic Rc1b, and PlsTsatB is derived as the loss at second saturation temperature PlsTsat2 based on the GEN-INV loss characteristic Lc2 and the thermal resistance characteristic Rc1b. In addition, the second saturation temperature Tsat2 and the loss at the second saturation temperature PlsTsat2 based on the GEN-INV loss characteristic Lc2 and the thermal resistance characteristic Rc1b can also be said to be the second saturation temperature Tsat2 and the loss at the second saturation temperature PlsTsat2 when the duty of the electric pump 22 is 40[%].

[0117] Similarly, the control device 50 derives the second saturation temperature Tsat2 and the loss at the second saturation temperature PlsTsat2 based on the GEN-INV loss characteristic Lc2 and the thermal resistance characteristic Rc2b, and the second saturation temperature Tsat2 and the loss at the second saturation temperature PlsTsat2 based on the GEN-INV loss characteristic Lc2 and the thermal resistance characteristic Rc3b. This allows the control device 50 to obtain the second saturation temperature Tsat2 and the loss at the second saturation temperature PlsTsat2 for each thermal resistance characteristic Rc, in other words, for each duty of the electric pump 22.

[0118] (4-3. Method of deriving the third saturation temperature and loss at the third saturation temperature in the first application example) Next, a method for deriving the third saturation temperature Tsat3 and the loss at the third saturation temperature PlsTsat3 in the first application example will be described. Fig. 6 is a diagram showing an example of a method for deriving the third saturation temperature Tsat3 and the loss at the third saturation temperature PlsTsat3 in the first application example.

[0119] In the first use example, the control device 50 (e.g., the loss characteristics derivation unit 51) derives, for example, a first-temperature loss PlsT1c, which is a VCU loss when the current I1 current, V1 voltage, and V2 voltage are used and the device temperature Tj is 25°C, by referring to a loss map Mp1c, as shown in a box marked with reference numeral 601 in FIG. 6 . Here, the loss map Mp1c is information indicating the VCU loss corresponding to each combination of the I1 current, V1 voltage, V2 voltage, and device temperature Tj, and is stored in advance in, for example, the storage unit 50b. Note that the loss map Mp1c only needs to be information that can identify the VCU loss from the I1 current, V1 voltage, V2 voltage, and device temperature Tj, and, similar to the loss map Mp1, may be configured as a group of multiple maps in terms of data.

[0120] 6, the control device 50 also derives the second temperature loss PlsT2c and the third temperature loss PlsT3c in the same manner as the first temperature loss PlsT1c. Here, the second temperature loss PlsT2c can be, for example, the VCU loss when the current I1 current, V1 voltage, and V2 voltage are used and the device temperature Tj is set to 75°C. The third temperature loss PlsT3b can be, for example, the VCU loss when the current I1 current, V1 voltage, and V2 voltage are used and the device temperature Tj is set to 175°C.

[0121] Next, the control device 50 (for example, the loss characteristic deriving unit 51) derives a VCU loss characteristic Lc3 that represents the VCU loss for each device temperature Tj based on the first temperature loss PlsT1c, the second temperature loss PlsT2c, and the third temperature loss PlsT3c, as shown in a box marked with reference numeral 602 in Fig. 6. The VCU loss characteristic Lc3 is another example of the loss characteristic Lc, and, similarly to the loss characteristic Lc, can be geometrically determined from, for example, the first temperature loss PlsT1c, the second temperature loss PlsT2c, and the third temperature loss PlsT3c.

[0122] Next, the control device 50 (for example, the flow rate derivation unit 52) ​​derives the flow rate Fw corresponding to the water temperature TWnow for each duty of the electric pump 22 by referring to the flow rate map Mp2, as shown in the box marked with reference numeral 603 in Fig. 6. In the example shown in Fig. 6, Fw1 is derived as the flow rate Fw when the duty of the electric pump 22 is 40[%], Fw2 is derived as the flow rate Fw when the duty is 60[%], and Fw3 is derived as the flow rate Fw when the duty is 80[%].

[0123] The process shown in the box marked with reference numeral 603 in Fig. 6 is the same as the process shown in the box marked with reference numeral 403 in Fig. 4. Therefore, if the control device 50 has already executed the process shown in the box marked with reference numeral 403 in Fig. 4, the control device 50 may use the processing result of the process shown in the box marked with reference numeral 403 in Fig. 4 as is, without re-executing the process shown in the box marked with reference numeral 603 in Fig. 6.

[0124] Next, the control device 50 (for example, the thermal resistance derivation unit 53) derives the thermal resistance Rt corresponding to each flow rate Fw based on each flow rate Fw derived by the above process, with reference to a thermal resistance map Mp3, as shown in the box marked with reference numeral 604 in Fig. 6. In the example shown in Fig. 6, when the flow rate Fw is Fw1 (in other words, when the duty is 40[%]), Rt1 is derived as the thermal resistance Rt, when the flow rate Fw is Fw2 (in other words, when the duty is 60[%]), Rt2 is derived as the thermal resistance Rt, and when the flow rate Fw is Fw3 (in other words, when the duty is 80[%]), Rt3 is derived as the thermal resistance Rt.

[0125] The process shown in the box marked with reference numeral 604 in Fig. 6 is the same as the process shown in the box marked with reference numeral 404 in Fig. 4. Therefore, if the control device 50 has already executed the process shown in the box marked with reference numeral 404 in Fig. 4, the control device 50 may use the processing result of the process shown in the box marked with reference numeral 404 in Fig. 4 as is, without re-executing the process shown in the box marked with reference numeral 604 in Fig. 6.

[0126] Next, the control device 50 (e.g., the thermal resistance characteristic derivation unit 54) derives a thermal resistance characteristic Rc corresponding to each thermal resistance Rt based on each thermal resistance Rt derived by the above process, as shown in the box marked with reference numeral 605 in Fig. 6. In the example shown in Fig. 6, a thermal resistance characteristic Rc1c is derived as the thermal resistance characteristic Rc when the thermal resistance Rt is Rt1 (in other words, when the duty is 40[%]). Furthermore, a thermal resistance characteristic Rc2c is derived as the thermal resistance characteristic Rc when the thermal resistance Rt is Rt2 (in other words, when the duty is 60[%]). Furthermore, a thermal resistance characteristic Rc3c is derived as the thermal resistance characteristic Rc when the thermal resistance Rt is Rt3 (in other words, when the duty is 80[%]).

[0127] For example, the thermal resistance characteristic Rc1c can be geometrically calculated from a first ultimate temperature when the loss of the power conversion device 10 is the loss at a first temperature PlsT1c and the thermal resistance Rt is Rt1, a second ultimate temperature when the loss of the power conversion device 10 is the loss at a second temperature PlsT2c and the thermal resistance Rt is Rt1, and a third ultimate temperature when the loss of the power conversion device 10 is the loss at a third temperature PlsT3c and the thermal resistance Rt is Rt1. Each of the first, second, and third ultimate temperatures can be calculated, for example, using the above formula (1). The thermal resistance characteristics Rc2c and Rc3c can also be calculated in the same way as the thermal resistance characteristic Rc1c.

[0128] Next, the control device 50 (for example, the saturation temperature / loss at saturation temperature derivation unit 55) derives the third saturation temperature Tsat3 and the loss at third saturation temperature PlsTsat3 for each thermal resistance characteristic Rc based on the VCU loss characteristic Lc3 derived by the above processing and each thermal resistance characteristic Rc, as shown in the box marked with the symbol 606 in Figure 6.

[0129] For example, the third saturation temperature Tsat3 and the loss at the third saturation temperature PlsTsat3 based on the VCU loss characteristic Lc3 and the thermal resistance characteristic Rc1c can be obtained as the intersection of the VCU loss characteristic Lc3 and the thermal resistance characteristic Rc1c on a plane having the loss of the power conversion device 10 (here, the VCU loss) on the horizontal axis and the device temperature Tj on the vertical axis. In the example shown in Fig. 6, TsatC is derived as the third saturation temperature Tsat3 based on the VCU loss characteristic Lc3 and the thermal resistance characteristic Rc1c, and PlsTsatC is derived as the loss at the third saturation temperature PlsTsat3 based on the VCU loss characteristic Lc3 and the thermal resistance characteristic Rc1c. In addition, the third saturation temperature Tsat3 and the loss PlsTsat3 at the third saturation temperature based on the VCU loss characteristic Lc3 and the thermal resistance characteristic Rc1c can also be said to be the third saturation temperature Tsat3 and the loss PlsTsat3 at the third saturation temperature when the duty of the electric pump 22 is 40%.

[0130] Similarly, the control device 50 derives the third saturation temperature Tsat3 and the loss at the third saturation temperature PlsTsat3 based on the VCU loss characteristic Lc3 and the thermal resistance characteristic Rc2c, and the third saturation temperature Tsat3 and the loss at the third saturation temperature PlsTsat3 based on the VCU loss characteristic Lc3 and the thermal resistance characteristic Rc3c. This allows the control device 50 to obtain the third saturation temperature Tsat3 and the loss at the third saturation temperature PlsTsat3 for each thermal resistance characteristic Rc, in other words, for each duty of the electric pump 22.

[0131] (4-4. Search for optimal duty) In the first use example, the control device 50 searches for an optimal duty of the electric pump 22 based on the first saturation temperature loss PlsTsat1, the second saturation temperature loss PlsTsat2, and the third saturation temperature loss PlsTsat3 derived as described above for each duty of the electric pump 22. Here, the optimal duty is the duty of the electric pump 22 that minimizes the sum of the first saturation temperature loss PlsTsat1, the second saturation temperature loss PlsTsat2, the third saturation temperature loss PlsTsat3, and the power consumption of the electric pump 22 when the V2 voltage is set to a predetermined value (for example, the current V2 voltage).

[0132] Fig. 7 is a diagram showing an example of a method for searching for an optimal duty in the first use example. In Fig. 7, the horizontal axis represents the duty of the electric pump 22, and the vertical axis represents the loss of the vehicle 1 (in other words, the power consumption).

[0133] When searching for the optimum duty, the control device 50 derives, for example, a first loss characteristic at saturation temperature 701, a second loss characteristic at saturation temperature 702, and a third loss characteristic at saturation temperature 703 shown in FIG.

[0134] Here, the first saturation temperature loss characteristic 701 represents the first saturation temperature loss PlsTsat1 (i.e., the saturation temperature loss PlsTsat based on the MOT-INV loss) for each duty of the electric pump 22. In other words, it represents the first saturation temperature loss PlsTsat1 corresponding to each duty. For example, the first saturation temperature loss characteristic 701 can be geometrically obtained from the first saturation temperature loss PlsTsat1 for each duty of the electric pump 22 obtained by the processing shown in FIG.

[0135] Further, the second saturation temperature loss characteristic 702 represents the second saturation temperature loss PlsTsat2 (i.e., the saturation temperature loss PlsTsat based on the GEN-INV loss) for each duty of the electric pump 22. In other words, the second saturation temperature loss PlsTsat2 corresponds to each duty. For example, the second saturation temperature loss characteristic 702 can be geometrically obtained from the second saturation temperature loss PlsTsat2 for each duty of the electric pump 22 obtained by the processing shown in FIG.

[0136] Further, the third saturation temperature loss characteristic 703 represents the third saturation temperature loss PlsTsat3 (i.e., the saturation temperature loss PlsTsat based on the VCU loss) for each duty of the electric pump 22. In other words, it represents the third saturation temperature loss PlsTsat3 according to each duty. For example, the third saturation temperature loss characteristic 703 can be geometrically obtained from the third saturation temperature loss PlsTsat3 for each duty of the electric pump 22 obtained by the processing shown in FIG.

[0137] 7 represents the power consumption of the electric pump 22 for each duty of the electric pump 22. In other words, it represents the power consumption of the electric pump 22 according to each duty. For example, information representing the EWP loss characteristic 704 is stored in advance in the storage unit 50b.

[0138] In the first use example, the control device 50 derives a total loss characteristic 710 based on, for example, a first loss characteristic 701 at saturation temperature, a second loss characteristic 702 at saturation temperature, a third loss characteristic 703 at saturation temperature, and an EWP loss characteristic 704. Here, the total loss characteristic 710 represents the sum of the first loss at saturation temperature PlsTsat1, the second loss at saturation temperature PlsTsat2, the third loss at saturation temperature PlsTsat3, and the power consumption of the electric pump 22 for each duty of the electric pump 22. In other words, the total loss characteristic 710 represents the sum of the first loss at saturation temperature PlsTsat1, the second loss at saturation temperature PlsTsat2, the third loss at saturation temperature PlsTsat3, and the power consumption of the electric pump 22 for each duty.

[0139] Then, the control device 50 searches for an optimal duty cycle based on the total loss characteristic 710. More specifically, at this time, the control device 50 searches, for example, from among the duties included in the "duty cycle applicable range," which is the range of duties that can be used as duties for actually driving the electric pump 22, for a duty cycle that minimizes the sum of the first saturation temperature loss PlsTsat1, the second saturation temperature loss PlsTsat2, the third saturation temperature loss PlsTsat3, and the power consumption of the electric pump 22, as the optimal duty cycle. In the example shown in FIG. 7, a duty cycle of 80[%] is searched for as the optimal duty cycle. The duty cycle applicable range is determined in advance by the manufacturer of the vehicle 1, etc.

[0140] After searching for the optimal duty in this way, the control device 50 drives the electric pump 22 at the optimal duty. This allows the electric pump 22 to be appropriately controlled at a duty that takes into account the MOT-INV loss, the GEN-INV loss, the VCU loss, and the power consumption of the electric pump 22, making it possible to reduce the power consumption in the vehicle 1.

[0141] In the example described here, the control device 50 searches for the optimal duty based on the first loss characteristic at saturation temperature 701, the second loss characteristic at saturation temperature 702, the third loss characteristic at saturation temperature 703, and the EWP loss characteristic 704, but this is not limited to this.

[0142] For example, when vehicle 1 is traveling in EV driving mode or when vehicle 1 is a BEV (Battery Electric Vehicle) that does not include second motor generator MG2, control device 50 may search for the optimal duty based on first saturation temperature loss characteristic 701, third saturation temperature loss characteristic 703, and EWP loss characteristic 704. Furthermore, when the power consumption of electric pump 22 is sufficiently small compared to the loss of power conversion device 10, control device 50 does not need to use EWP loss characteristic 704 in searching for the optimal duty. Furthermore, control device 50 may simply search for the optimal duty using any one of first saturation temperature loss characteristic 701, second saturation temperature loss characteristic 702, and third saturation temperature loss characteristic 703.

[0143] As described above, in the first usage example, the control device 50 derives the flow rate Fw when the driving state of the electric pump 22 is set to a predetermined first state (e.g., Duty 40[%]) and when it is set to a predetermined second state (e.g., Duty 60[%]), and based on the derived flow rates Fw, derives the thermal resistance Rt when the electric pump 22 is set to the first state and when it is set to the second state. The control device 50 then derives a saturation temperature Tsat (e.g., the first saturation temperature Tsat1 or the second saturation temperature Tsat2) and a saturation temperature loss PlsTsat (e.g., the first saturation temperature loss PlsTsat1 or the second saturation temperature loss PlsTsat2) for each of the first and second states based on the loss characteristic Lc (e.g., the MOT-INV loss characteristic Lc1 or the GEN-INV loss characteristic Lc2) of the power conversion device 10 and the thermal resistance characteristic Rc (e.g., the thermal resistance characteristics Rc1a, Rc1b or the thermal resistance characteristics Rc2a, Rc2b) corresponding to each of the derived thermal resistances Rt, and controls the electric pump 22 based on each saturation temperature loss PlsTsat. This makes it possible to control the electric pump 22 in consideration of the saturation temperature loss PlsTsat for each flow rate Fw.

[0144] [5.Second usage example] Next, a second application example of the present invention will be described. This second application example is an example in which the control device 50 controls the power conversion device 10 based on the loss at saturation temperature PlsTsat. In the second application example, as in the first application example, the control device 50 derives a first saturation temperature Tsat1, a second saturation temperature Tsat2, and a third saturation temperature Tsat3 as the saturation temperature Tsat, and derives a first saturation temperature loss PlsTsat1, a second saturation temperature loss PlsTsat2, and a third saturation temperature loss PlsTsat3 as the loss at saturation temperature PlsTsat. Note that the following description will focus on points that are different from the description of the first application example described above, and descriptions of points that are similar to the description of the first application example will be omitted as appropriate.

[0145] (Method of deriving the first saturation temperature and the loss at the first saturation temperature in the second application example) FIG. 8 is a diagram showing an example of a method for deriving the first saturation temperature Tsat1 and the loss at the first saturation temperature PlsTsat1 in the second use example.

[0146] In the second usage example, the control device 50 (for example, the loss characteristics derivation unit 51) derives, by referring to the loss map Mp1a, the loss PlsT1d at the first temperature, which is the MOT-INV loss when, for example, the current MOT rotation speed and MOT torque are used, the V2 voltage is set to a predetermined first voltage (200 [V] in the example shown in FIG. 8), and the device temperature Tj is set to 25 [°C], as shown in the box marked with the symbol 801 in FIG. 8.

[0147] 8, the control device 50 also derives the second temperature loss PlsT2d and the third temperature loss PlsT3d in the same manner as the first temperature loss PlsT1d. Here, the second temperature loss PlsT2d can be, for example, the MOT-INV loss when the current MOT rotation speed and MOT torque are used, the V2 voltage is the first voltage, and the device temperature Tj is 75°C. The third temperature loss PlsT3d can be, for example, the MOT-INV loss when the current MOT rotation speed and MOT torque are used, the V2 voltage is the first voltage, and the device temperature Tj is 175°C.

[0148] Next, the control device 50 (for example, the loss characteristic deriving unit 51) derives the MOT-INV loss characteristic Lc1d as the MOT-INV loss characteristic Lc1 based on the first temperature loss PlsT1d, the second temperature loss PlsT2d, and the third temperature loss PlsT3d, as shown in the box marked with reference numeral 802 in Fig. 8. The MOT-INV loss characteristic Lc1d can be geometrically determined from the first temperature loss PlsT1d, the second temperature loss PlsT2d, and the third temperature loss PlsT3d, for example.

[0149] Next, as shown in the box marked with the symbol 801 in FIG. 8, the control device 50 derives the loss PlsT1e at the first temperature, which is the MOT-INV loss when the current MOT rotation speed and MOT torque are used, the V2 voltage is set to a predetermined second voltage (350 [V] in the example shown in FIG. 8), and the device temperature Tj is set to 25 [°C], by referring to the loss map Mp1a.

[0150] 8, the control device 50 also derives the second temperature loss PlsT2e and the third temperature loss PlsT3e in the same manner as the first temperature loss PlsT1e. Here, the second temperature loss PlsT2e can be, for example, the MOT-INV loss when the current MOT rotation speed and MOT torque are used, the V2 voltage is the second voltage, and the device temperature Tj is 75°C. The third temperature loss PlsT3e can be, for example, the MOT-INV loss when the current MOT rotation speed and MOT torque are used, the V2 voltage is the second voltage, and the device temperature Tj is 175°C.

[0151] Next, the control device 50 (for example, the loss characteristic deriving unit 51) derives the MOT-INV loss characteristic Lc1e as the MOT-INV loss characteristic Lc1 based on the first temperature loss PlsT1e, the second temperature loss PlsT2e, and the third temperature loss PlsT3e, as shown in the box marked with reference numeral 802 in Fig. 8. The MOT-INV loss characteristic Lc1e can be geometrically determined from, for example, the first temperature loss PlsT1e, the second temperature loss PlsT2e, and the third temperature loss PlsT3e.

[0152] Next, as shown in the box marked with the symbol 801 in FIG. 8, the control device 50 derives the first temperature loss PlsT1f, which is the MOT-INV loss when the current MOT rotation speed and MOT torque are used, the V2 voltage is set to a predetermined third voltage (500 [V] in the example shown in FIG. 8), and the device temperature Tj is set to 25 [°C], by referring to the loss map Mp1a.

[0153] 8, the control device 50 also derives the second temperature loss PlsT2f and the third temperature loss PlsT3f in the same manner as the first temperature loss PlsT1f. Here, the second temperature loss PlsT2f can be, for example, the MOT-INV loss when the current MOT rotation speed and MOT torque are used, the V2 voltage is set as the third voltage, and the device temperature Tj is set as 75°C. The third temperature loss PlsT3f can be, for example, the MOT-INV loss when the current MOT rotation speed and MOT torque are used, the V2 voltage is set as the third voltage, and the device temperature Tj is set as 175°C.

[0154] Next, the control device 50 (for example, the loss characteristic deriving unit 51) derives the MOT-INV loss characteristic Lc1f as the MOT-INV loss characteristic Lc1 based on the first temperature loss PlsT1f, the second temperature loss PlsT2f, and the third temperature loss PlsT3f, as shown in the box marked with reference numeral 802 in Fig. 8. The MOT-INV loss characteristic Lc1f can be geometrically determined from, for example, the first temperature loss PlsT1f, the second temperature loss PlsT2f, and the third temperature loss PlsT3f.

[0155] In this way, in the second use example, the control device 50 derives the MOT-INV loss characteristic Lc1 when the V2 voltage is set to a plurality of different voltage values, in other words, the MOT-INV loss characteristic Lc1 for each V2 voltage. Then, the control device 50 derives the first saturation temperature Tsat1 and the loss at first saturation temperature PlsTsat1 for each V2 voltage from the intersection of each MOT-INV loss characteristic Lc1 with the thermal resistance characteristic Rc when the duty of the electric pump 22 is set to a predetermined value (for example, the current duty) (for example, the intersection on a plane with the loss of the power conversion device 10 on the horizontal axis and the device temperature Tj on the vertical axis).

[0156] Similarly, the control device 50 also derives the second saturation temperature Tsat2 and the loss at the second saturation temperature PlsTsat2 for each V2 voltage, and the third saturation temperature Tsat3 and the loss at the third saturation temperature PlsTsat3 for each V2 voltage.

[0157] (5-2. Search for the optimal V2 voltage) In the second use example, the control device 50 searches for an optimal V2 voltage based on the first saturation temperature loss PlsTsat1, the second saturation temperature loss PlsTsat2, and the third saturation temperature loss PlsTsat3 for each V2 voltage derived as described above. Here, the optimal V2 voltage is a voltage value as the V2 voltage that minimizes the sum of the first saturation temperature loss PlsTsat1, the second saturation temperature loss PlsTsat2, the third saturation temperature loss PlsTsat3, and the power consumption of the electric pump 22 when the duty of the electric pump 22 is set to a predetermined value (for example, the current duty).

[0158] Fig. 9 is a diagram showing an example of a method for searching for the optimum V2 voltage in the second use example. In Fig. 9, the horizontal axis represents the V2 voltage, and the vertical axis represents the loss of the vehicle 1 (in other words, the power consumption).

[0159] When searching for the optimum V2 voltage, the control device 50 derives, for example, a first loss characteristic at saturation temperature 901, a second loss characteristic at saturation temperature 902, and a third loss characteristic at saturation temperature 903 shown in FIG.

[0160] Here, the first saturation temperature loss characteristic 901 represents the first saturation temperature loss PlsTsat1 for each V2 voltage (i.e., the saturation temperature loss PlsTsat based on the MOT-INV loss), in other words, the first saturation temperature loss PlsTsat1 corresponding to the voltage value of each V2 voltage. For example, the first saturation temperature loss characteristic 901 can be geometrically obtained from the first saturation temperature loss PlsTsat1 for each V2 voltage obtained by the processing shown in FIG.

[0161] Further, the second saturation temperature loss characteristic 902 represents the second saturation temperature loss PlsTsat2 for each V2 voltage (i.e., the saturation temperature loss PlsTsat based on the GEN-INV loss), in other words, the second saturation temperature loss PlsTsat2 corresponding to each V2 voltage. For example, the second saturation temperature loss characteristic 902 can be geometrically determined from the second saturation temperature loss PlsTsat2 for each V2 voltage.

[0162] Furthermore, the third saturation temperature loss characteristic 903 represents the third saturation temperature loss PlsTsat3 for each V2 voltage (i.e., the saturation temperature loss PlsTsat based on the VCU loss), in other words, the third saturation temperature loss PlsTsat3 corresponding to the voltage value of each V2 voltage. For example, the third saturation temperature loss characteristic 903 can be geometrically determined from the third saturation temperature loss PlsTsat3 for each V2 voltage.

[0163] 9 represents the power consumption of the electric pump 22 for each V2 voltage, in other words, represents the power consumption of the electric pump 22 according to each voltage value as the V2 voltage. For example, information representing the EWP loss characteristic 904 is stored in advance in the storage unit 50b.

[0164] In the second use example, the control device 50 derives a total loss characteristic 910 based on, for example, a first saturation temperature loss characteristic 901, a second saturation temperature loss characteristic 902, a third saturation temperature loss characteristic 903, and an EWP loss characteristic 904. Here, the total loss characteristic 910 represents the sum of the first saturation temperature loss PlsTsat1, the second saturation temperature loss PlsTsat2, the third saturation temperature loss PlsTsat3, and the power consumption of the electric pump 22 for each V2 voltage. In other words, the total loss characteristic 910 represents the sum of the first saturation temperature loss PlsTsat1, the second saturation temperature loss PlsTsat2, the third saturation temperature loss PlsTsat3, and the power consumption of the electric pump 22 for each voltage value as the V2 voltage.

[0165] Then, the control device 50 searches for the optimal V2 voltage based on the total loss characteristic 910. More specifically, at this time, the control device 50 searches, for example, from voltage values ​​included in the "V2 voltage applicable range," which is a range of voltage values ​​that can be used as the V2 voltage, for a voltage value that minimizes the sum of the first saturation temperature loss PlsTsat1, the second saturation temperature loss PlsTsat2, the third saturation temperature loss PlsTsat3, and the power consumption of the electric pump 22, as the optimal V2 voltage. In the example shown in FIG. 9, 420 [V] is searched for as the optimal V2 voltage. The V2 voltage applicable range is determined in advance by the manufacturer of the vehicle 1, etc.

[0166] After searching for the optimal V2 voltage in this manner, the control device 50 controls the power conversion device 10 so that the actual V2 voltage becomes the optimal V2 voltage. This allows the first motor generator MG1 and the like to be operated appropriately using the V2 voltage that takes into account the MOT-INV loss, GEN-INV loss, VCU loss, and the power consumption of the electric pump 22, making it possible to reduce power consumption in the vehicle 1.

[0167] In the example described here, the control device 50 searches for the optimal V2 voltage based on the first loss characteristic at saturation temperature 901, the second loss characteristic at saturation temperature 902, the third loss characteristic at saturation temperature 903, and the EWP loss characteristic 904, but this is not limited to this.

[0168] For example, when vehicle 1 is traveling in EV driving mode or when vehicle 1 is a BEV that does not include second motor generator MG2, control device 50 may search for the optimal V2 voltage based on first saturation temperature loss characteristic 901, third saturation temperature loss characteristic 903, and EWP loss characteristic 904. Furthermore, when the power consumption of electric pump 22 is sufficiently small compared to the loss of power conversion device 10, control device 50 does not need to use EWP loss characteristic 904 in searching for the optimal V2 voltage. Furthermore, control device 50 may simply search for the optimal V2 voltage using any one of first saturation temperature loss characteristic 901, second saturation temperature loss characteristic 902, and third saturation temperature loss characteristic 903.

[0169] As described above, in the second use example, the control device 50 derives the loss characteristics Lc (e.g., MOT-INV loss characteristics Lc1d, Lc1e) when the V2 voltage is set to a predetermined first voltage value (e.g., 200 [V]) and when the V2 voltage is set to a predetermined second voltage value (e.g., 350 [V]), and derives the saturation temperature Tsat and the loss at saturation temperature PlsTsat when the V2 voltage is set to the first voltage value and the second voltage value based on the respective loss characteristics Lc and thermal resistance characteristic Rc, and controls the power conversion device 10 based on the respective loss at saturation temperature PlsTsat (e.g., first loss characteristic at saturation temperature 901). This makes it possible to control the power conversion device 10 in consideration of the loss at saturation temperature PlsTsat for each V2 voltage.

[0170] [6. Third usage example] Next, a third application example of the present invention will be described. This third application example is an example in which the control device 50 (e.g., vehicle control unit 56) determines the state of the vehicle 1 based on the saturation temperature Tsat. More specifically, in the third application example, the control device 50 determines the presence or absence of an abnormality in the device temperature sensor 36 as the state of the vehicle 1 based on the device temperature Tj detected by the device temperature sensor 36 and the saturation temperature Tsat. Note that, in the third application example, unless otherwise specified, the saturation temperature Tsat is the saturation temperature Tsat when the first motor generator MG1 and the like are operated under the current operating conditions and the power conversion device 10 is cooled under the current cooling conditions (e.g., the duty of the electric pump 22).

[0171] If the device temperature sensor 36 is normal, it is believed that the device temperature Tj detected by the device temperature sensor 36 will eventually stabilize near the saturation temperature Tsat. Therefore, if the device temperature Tj detected by the device temperature sensor 36 continues to deviate from the saturation temperature Tsat for a certain period of time, there is a possibility that an abnormality (for example, a malfunction) has occurred in the device temperature sensor 36.

[0172] Therefore, in the third use example, the control device 50 determines that the device temperature sensor 36 is abnormal if the temperature difference between the device temperature Tj and the saturation temperature Tsat (hereinafter also referred to as the "temperature difference ΔT") detected by the device temperature sensor 36, in other words, the value obtained by subtracting the saturation temperature Tsat from the device temperature Tj, remains equal to or exceeds a predetermined threshold value for a predetermined period of time Tmx. In other words, the control device 50 determines that the device temperature sensor 36 is normal if the temperature difference ΔT is less than the threshold value or if the temperature difference ΔT exceeds the threshold value but only momentarily. This enables the control device 50 to accurately determine whether or not the device temperature sensor 36 is abnormal based on the saturation temperature Tsat. The threshold value and the predetermined period of time Tmx are set in advance by the manufacturer of the vehicle 1, etc. In addition, from the viewpoint of preventing erroneous detection of an abnormality in the device temperature sensor 36, it is desirable that the control device 50 determine whether or not the device temperature sensor 36 is abnormal only under circumstances in which the temperature change in the power conversion device 10 is relatively small, such as when the vehicle 1 is stopped or under low load.

[0173] Fig. 10 is a diagram showing an example of a method for detecting an abnormality in the device temperature sensor 36 in the third use example. In (A) of Fig. 10, the vertical axis represents the device temperature Tj detected by the device temperature sensor 36, and the horizontal axis represents the time. In (B) of Fig. 10, the vertical axis represents the temperature difference ΔT, and the horizontal axis represents the time.

[0174] As shown in (B) of Figure 10, in the third use example, for example, a higher failure determination threshold ThH and a lower failure determination threshold ThL (where the lower failure determination threshold ThL<the higher failure determination threshold ThH) are set as thresholds related to the temperature difference ΔT.

[0175] As an example, assume that the device temperature Tj detected by the device temperature sensor 36 changes as indicated by the solid line 1010 shown in Fig. 10(A), and the temperature difference ΔT changes as indicated by the solid line 1011 shown in Fig. 10(B). In this case, during the period from time t10 to time t11, the temperature difference ΔT is less than the high failure determination threshold ThH and greater than the low failure determination threshold ThL, and therefore the control device 50 determines that the device temperature sensor 36 is normal.

[0176] In this case, the temperature difference ΔT becomes equal to or greater than the high-temperature failure determination threshold ThH from time t11, and even at time t12, when a predetermined period Tmx has elapsed since time t11, the temperature difference ΔT remains equal to or greater than the high-temperature failure determination threshold ThH. If the temperature difference ΔT remains equal to or greater than the high-temperature failure determination threshold ThH for the predetermined period Tmx, the control device 50 determines that a "high-temperature failure" has occurred in the device temperature sensor 36. Here, a high-temperature failure is an abnormality in which the device temperature sensor 36 detects a device temperature Tj that is higher than normal.

[0177] As another example, assume that the device temperature Tj detected by the device temperature sensor 36 changes as indicated by the solid line 1020 shown in Fig. 10A, and the temperature difference ΔT changes as indicated by the solid line 1021 shown in Fig. 10B. In this case, during the period from time t10 to time t11, the temperature difference ΔT is less than the high failure determination threshold ThH and greater than the low failure determination threshold ThL, and therefore the control device 50 determines that the device temperature sensor 36 is normal.

[0178] In this case, the temperature difference ΔT becomes equal to or less than the lower fault determination threshold ThL from time t11, and even at time t12, when a predetermined period Tmx has elapsed since time t11, the temperature difference ΔT remains equal to or less than the lower fault determination threshold ThL. In this manner, if the temperature difference ΔT remains equal to or less than the lower fault determination threshold ThL for the predetermined period Tmx, the control device 50 determines that a "low fault" has occurred in the device temperature sensor 36. Here, a low fault is an abnormality in which the device temperature sensor 36 detects a device temperature Tj that is lower than normal.

[0179] As described above, in the third usage example, the control device 50 determines whether or not the device temperature sensor 36 is abnormal based on the device temperature Tj and the saturation temperature Tsat detected by the device temperature sensor 36. This makes it possible to accurately determine whether or not the device temperature sensor 36 is abnormal.

[0180] In the third usage example, when the control device 50 determines that an abnormality has occurred in the device temperature sensor 36, the control device 50 may, for example, notify the occupant of the vehicle 1 that an abnormality has occurred in the device temperature sensor 36 via an alarm device (for example, a display) (not shown) provided in the vehicle 1. In this way, it is possible to prompt the occupant of the vehicle 1 to have the vehicle 1 inspected.

[0181] (Modification of the third use example) Next, a modified example of the third usage example will be described. The modified example described below is an example in which multiple device temperature sensors 36, such as a first device temperature sensor 36a, a second device temperature sensor 36b, and a third device temperature sensor 36c, are provided, and the control device 50 determines whether or not there is an abnormality in the water temperature sensor 35 based on the device temperatures Tj and saturation temperatures Tsat detected by each of these sensors. Note that the following description will focus on points that are different from the example described above, and descriptions of points that are similar to the example described above will be omitted or simplified as appropriate.

[0182] In this modification, the device temperature Tj detected by the first device temperature sensor 36a is also referred to as the "first device temperature," and the temperature difference between the first device temperature and the saturation temperature Tsat is also referred to as the "temperature difference ΔTa." The device temperature Tj detected by the second device temperature sensor 36b is also referred to as the "second device temperature," and the temperature difference between the second device temperature and the saturation temperature Tsat is also referred to as the "temperature difference ΔTb." The device temperature Tj detected by the third device temperature sensor 36c is also referred to as the "third device temperature," and the temperature difference between the third device temperature and the saturation temperature Tsat is also referred to as the "temperature difference ΔTc."

[0183] In this modified example, an abnormality in the first device temperature refers to, for example, the temperature difference ΔTa being equal to or greater than the higher failure determination threshold ThH or equal to or less than the lower failure determination threshold ThL. An abnormality in the second device temperature refers to, for example, the temperature difference ΔTb being equal to or greater than the higher failure determination threshold ThH or equal to or less than the lower failure determination threshold ThL. An abnormality in the third device temperature refers to, for example, the temperature difference ΔTc being equal to or greater than the higher failure determination threshold ThH or equal to or less than the lower failure determination threshold ThL.

[0184] Fig. 11 is a diagram showing an example of a determination made by the control device 50 in accordance with the state of each device temperature in a modified example of the third use example. As shown in table 1100 in Fig. 11, in this modified example, if "State A-1," "State A-2," or "State A-3" occurs in which only one of the first, second, and third device temperatures is abnormal, and if this state continues for a predetermined period of time Tmx, the control device 50 determines that an abnormality has occurred in the device temperature sensor that detected that device temperature.

[0185] 11, when "State B-1," "State B-2," or "State B-3" occurs in which two of the first, second, and third device temperatures are abnormal and the other is normal, the control device 50 does not determine that an abnormality has occurred in any of the device temperature sensors 36a, 36b, and 36c, but rather determines that an abnormality is being determined for the water temperature sensor 35. This is because it is considered unlikely that two of the first, second, and third device temperature sensors 36a, 36b, and 36c will become abnormal at the same time.

[0186] 11, when "State C" occurs, in which the first device temperature, the second device temperature, and the third device temperature are all abnormal, and this state continues for a predetermined period of time Tmx, the control device 50 determines that an abnormality has occurred in the water temperature sensor 35. In other words, when "State C" occurs, it is more likely that the value of the water temperature TW used to derive the saturation temperature Tsat is abnormal, i.e., that an abnormality has occurred in the water temperature sensor 35, than that an abnormality has occurred in each of the device temperature sensors 36a, 36b, and 36c. Therefore, when "State C" occurs, the control device 50 determines that an abnormality has occurred in the water temperature sensor 35, thereby preventing erroneous detection of an abnormality in each of the device temperature sensors 36a, 36b, and 36c and enabling accurate detection of an abnormality in the water temperature sensor 35.

[0187] Figure 12 is a diagram showing an example of a method for detecting an abnormality in a water temperature sensor in a modified example of the third use example. In (A) of Figure 12, the vertical axis represents the temperature difference ΔTa, and the horizontal axis represents the time. In (B) of Figure 12, the vertical axis represents the temperature difference ΔTb, and the horizontal axis represents the time. In (C) of Figure 12, the vertical axis represents the temperature difference ΔTc, and the horizontal axis represents the time.

[0188] 12, from time t21, only the temperature difference ΔTa becomes equal to or greater than the high failure determination threshold ThH, and therefore the control device 50 determines the state of the vehicle 1 as "state A-1." Thereafter, from time t22, before the predetermined period Tmx has elapsed since time t21, the temperature difference ΔTb also becomes equal to or greater than the high failure determination threshold ThH, and therefore the control device 50 determines the state of the vehicle 1 as "state B-1."

[0189] Then, at time t23 after time t22, the temperature difference ΔTc also becomes equal to or greater than the high failure determination threshold ThH, so the control device 50 determines that the state of the vehicle 1 is "State C." Thereafter, even at time t24, when a predetermined period of time Tmx has elapsed since time t23, the temperature differences ΔTa, ΔTb, and ΔTc remain equal to or greater than the high failure determination threshold ThH. In this way, when the state in which the temperature differences ΔTa, ΔTb, and ΔTc remain equal to or greater than the high failure determination threshold ThH (i.e., "State C") continues for the predetermined period of time Tmx, the control device 50 determines that an abnormality has occurred in the water temperature sensor 35.

[0190] In the example described here, the control device 50 determines that an abnormality has occurred in the water temperature sensor 35 when the state of the vehicle 1 is "State C," but this is not limited to this. For example, the control device 50 may also determine that an abnormality has occurred in the water temperature sensor 35 when the state of the vehicle 1 is "State B-1," "State B-2," or "State B-3."

[0191] In the example described here, three device temperature sensors 36, namely, the first device temperature sensor 36a, the second device temperature sensor 36b, and the third device temperature sensor 36c, are provided, but this is not limiting. For example, two device temperature sensors 36 may be provided, and the control device 50 may determine that an abnormality has occurred in the water temperature sensor 35 if the device temperatures corresponding to these two device temperature sensors are all abnormal. Alternatively, four or more device temperature sensors 36 may be provided, and the control device 50 may determine that an abnormality has occurred in the water temperature sensor 35 if the device temperatures corresponding to these two or more device temperature sensors are all abnormal, or if a predetermined number of two or more device temperatures are abnormal.

[0192] As described above, in this modification, the control device 50 determines whether the water temperature sensor 35 is abnormal based on the device temperatures Tj and saturation temperatures Tsat detected by the respective device temperature sensors. This makes it possible to accurately determine whether the water temperature sensor 35 is abnormal.

[0193] [7. Fourth usage example] Next, a fourth application example of the present invention will be described. In this fourth application example, the control device 50 (for example, the vehicle control unit 56) determines the load state of the vehicle 1 based on the saturation temperature Tsat, and controls the vehicle 1 based on the determination result.

[0194] 13 is a diagram illustrating an example of a vehicle control method in the fourth usage example. As shown in FIG. 13, in the fourth usage example, a cooling priority threshold and a warm-up priority threshold are provided as thresholds that are set based on the device temperature Tj detected by the device temperature sensor 36. For example, the control device 50 sets the cooling priority threshold to a temperature obtained by adding a predetermined value greater than 0 to the device temperature Tj, and sets the warm-up priority threshold to a temperature obtained by subtracting a predetermined value greater than 0 from the device temperature Tj. Here, the predetermined values ​​are determined in advance by the manufacturer of the vehicle 1, etc.

[0195] 13, in the fourth usage example, when the saturation temperature Tsat is lower than the cooling priority threshold and higher than the warm-up priority threshold, i.e., when the vehicle 1 is in a medium load state, the control device 50 determines that the state of the vehicle 1 is "pattern α" and executes efficiency-priority control. In the efficiency-priority control, the control device 50 optimizes the efficiency of the vehicle 1 by, for example, controlling the electric pump 22 at the optimal duty cycle found as described in the first usage example, or by controlling the power conversion device 10 at the optimal V2 voltage found as described in the second usage example.

[0196] Furthermore, when the saturation temperature Tsat is equal to or higher than the cooling priority threshold, i.e., when the vehicle 1 is in a high-load state, the control device 50 determines that the state of the vehicle 1 is "pattern β" and executes cooling priority control. In the cooling priority control, the control device 50 increases the duty of the electric pump 22 from the current value to suppress a temperature rise in the power conversion device 10. At this time, the control device 50 may set the duty of the electric pump 22 to the maximum value within the applicable range of the duty.

[0197] Furthermore, when the saturation temperature Tsat is equal to or lower than the warm-up priority threshold, i.e., when the vehicle 1 is in a low-load state, the control device 50 determines that the state of the vehicle 1 is "pattern γ" and executes warm-up priority control. In the warm-up priority control, the control device 50 promotes a temperature rise in the power conversion device 10 by reducing the duty of the electric pump 22 from the current value. At this time, the control device 50 may set the duty of the electric pump 22 to the minimum value within the applicable range of duty.

[0198] As described above, in the fourth usage example, the control device 50 determines the load state of the vehicle 1 based on the device temperature Tj and the saturation temperature Tsat detected by the device temperature sensor 36, and controls the vehicle 1 based on the determination result, thereby making it possible to appropriately control the vehicle 1 taking into account the load state of the vehicle 1.

[0199] In the above-described embodiment, an example has been described in which the control device of the present invention is realized by the control device 50 mounted on the vehicle 1, but this is not limiting. For example, the control device of the present invention may be realized by a server capable of communicating with the control device 50. In this case, for example, each of the processes of the control device 50 described above may be performed by a processing unit realized by the CPU of the server. Furthermore, the control device of the present invention may be realized by cooperation between the control device 50 and the server, and for example, some of the processes of the control device 50 described above may be executed by the server.

[0200] The control method described in the above-described embodiment can be realized by executing a prepared program on a computer (in other words, a processor). This program (control program) is stored in a computer-readable storage medium and executed by being read from the storage medium. This program may be provided in a form stored in a non-volatile (non-transient) storage medium such as a flash memory, or may be provided via a network such as the Internet. The computer that executes this program may be included in the vehicle 1, or may be included in an external device (e.g., a server) that can communicate with the vehicle 1.

[0201] Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention.

[0202] For example, in the above-described embodiment, the moving body of the present invention is the vehicle 1, which is a hybrid electric vehicle, but is not limited to this. For example, the moving body of the present invention may be a BEV, an eVTOL (electric vertical take-off and landing aircraft), or a drone (unmanned aerial vehicle).

[0203] This specification etc. describes at least the following matters. Note that the components etc. corresponding to those in the above embodiment are shown in parentheses, but are not limited to these.

[0204] (1) A control method executed by a computer (control device 50) that controls a moving body (vehicle 1) including motor generators (first motor generator MG1, second motor generator MG2), power conversion devices (power conversion device 10, first inverter 11, second inverter 12, voltage conversion device 13) that exchange power with the motor generators, and a cooling device (cooling device 20) that cools the power conversion devices, The computer Based on the operating conditions of the motor generator, a loss characteristic (loss characteristic Lc) representing a loss for each temperature of the power conversion device when the motor generator is operated under the operating conditions is derived (step Sp3); Based on the cooling conditions of the power conversion device by the cooling device, a thermal resistance (thermal resistance Rt) of the power conversion device when the power conversion device is cooled under the cooling conditions is derived (step Sp5); A thermal resistance characteristic (thermal resistance characteristic Rc) representing an attained temperature for each loss of the power conversion device is derived based on the loss characteristic and the thermal resistance (step Sp6); Based on the loss characteristics and the thermal resistance characteristics, a saturation temperature (saturation temperature Tsat) that is the temperature reached by the power conversion device when the motor generator is operated under the operating conditions and the power conversion device is cooled under the cooling conditions, and a loss at saturation temperature (loss at saturation temperature PlsTsat) that is the loss of the power conversion device at the saturation temperature are derived (step Sp7); Controlling the moving body based on the saturation temperature and / or the loss at saturation temperature (step Sp8); A method of control, which performs processing.

[0205] According to (1), it is possible to derive the saturation temperature and the loss at saturation temperature when the motor generator is operated under predetermined operating conditions and the power conversion device is cooled under predetermined cooling conditions, so it is possible to control a moving object taking into account the saturation temperature and / or the loss at saturation temperature, which in turn can contribute to improving the energy efficiency of the moving object.

[0206] (2) The control method according to (1), The computer In a plane in which one axis represents the loss of the power conversion device and the other axis represents the temperature of the power conversion device, the loss of the power conversion device corresponding to an intersection (intersection CP) between the loss characteristic and the thermal resistance characteristic is derived as the loss at saturation temperature, and the temperature of the power conversion device corresponding to the intersection is derived as the saturation temperature. Control method.

[0207] According to (2), the saturation temperature and the loss at the saturation temperature can be calculated accurately by simple calculation.

[0208] (3) The control method according to (1) or (2), The computer The loss characteristics are derived based on the rotation speed (MOT rotation speed, GEN rotation speed) and output torque (MOT torque, GEN torque) of the motor generator, and the voltage value (V2 voltage) of the power exchanged between the motor generator and the power conversion device, as the operating conditions. Control method.

[0209] According to (3), it is possible to derive loss characteristics taking into consideration the rotation speed and output torque of the motor generator and the voltage value of the electric power exchanged between the motor generator and the power conversion device.

[0210] (4) The control method according to (3), The computer deriving the loss characteristics when the voltage value is a predetermined first voltage value and when the voltage value is a predetermined second voltage value different from the first voltage value; deriving the saturation temperature and the loss at the saturation temperature when the first voltage value is set and when the second voltage value is set based on the loss characteristic and the thermal resistance characteristic; controlling the power conversion devices based on the respective losses at saturated temperature; Control method.

[0211] According to (4), it is possible to control the power conversion device in consideration of the loss at saturation temperature for each voltage value of the power exchanged between the motor generator and the power conversion device.

[0212] (5) The control method according to (1) or (2), The cooling device includes a cooling circuit (cooling circuit 21) through which cooling water circulates, and an electric pump (electric pump 22) that pumps the cooling water in the cooling circuit, The moving body includes a water temperature sensor (water temperature sensor 35) that detects the temperature of the cooling water, The computer As the cooling condition, a flow rate (flow rate Fw) of the cooling water pumped by the electric pump per unit time is derived based on the temperature (water temperature TW) of the cooling water detected by the water temperature sensor and the driving state (duty) of the electric pump (step Sp4); Deriving the thermal resistance based on the flow rate. Control method.

[0213] According to (5), it is possible to appropriately derive the thermal resistance of the power conversion device without providing a flow rate sensor that detects the flow rate of the cooling water pressure-fed by the electric pump.

[0214] (6) The control method according to (5), The computer deriving the flow rate when the drive state of the electric pump is in a predetermined first state and when the drive state is in a predetermined second state different from the first state; deriving the thermal resistance when the first state is set and the thermal resistance when the second state is set based on the flow rates; deriving the saturation temperature and the loss at the saturation temperature for the first state and the second state based on the loss characteristic and the thermal resistance characteristic corresponding to each of the thermal resistances; controlling the electric pump based on each of the losses at saturated temperature; Control method.

[0215] According to (6), it is possible to control the electric pump in consideration of the loss at the saturated temperature for each flow rate of the cooling water pumped by the electric pump.

[0216] (7) The control method according to (1) or (2), the moving body includes a device temperature sensor (device temperature sensor 36) that detects the temperature of the power conversion device; The computer determining whether the device temperature sensor is abnormal based on the temperature of the power conversion device detected by the device temperature sensor and the saturation temperature; Control method.

[0217] According to (7), it is possible to accurately determine whether or not the device temperature sensor that detects the temperature of the power conversion device is abnormal.

[0218] (8) The control method according to (1) or (2), The cooling device includes a cooling circuit (cooling circuit 21) through which cooling water circulates, The moving body includes a water temperature sensor (water temperature sensor 35) that detects the temperature of the cooling water, and a plurality of device temperature sensors (first device temperature sensor 36a, second device temperature sensor 36b, third device temperature sensor 36c) that detect the temperatures of the power conversion devices, The computer determining whether the water temperature sensor is abnormal based on the temperatures of the power conversion devices detected by the device temperature sensors and the saturation temperature; Control method.

[0219] According to (8), it is possible to accurately determine whether or not the water temperature sensor that detects the temperature of the cooling water circulating through the cooling circuit is abnormal.

[0220] (9) The control method according to (1) or (2), the moving body includes a device temperature sensor (device temperature sensor 36) that detects the temperature of the power conversion device; The computer determining a load state of the moving body based on the temperature of the power conversion device detected by the device temperature sensor and the saturation temperature, and controlling the moving body based on the determination result; Control method.

[0221] According to (9), it is possible to appropriately control the moving body in consideration of the load state of the moving body.

[0222] (10) The control method according to (1) or (2), the moving body includes a plurality of motor generators (a first motor generator MG1, a second motor generator MG2) as the motor generators, The computer deriving the saturation temperature and the loss at the saturation temperature for each of the motor generators; Control method.

[0223] According to (10), even if a moving body is equipped with multiple motor generators, it is possible to control the moving body taking into account the saturation temperature and / or loss at saturation temperature corresponding to each motor generator.

[0224] (11) A control device (control device 50) for controlling a moving body (vehicle 1) including motor generators (first motor generator MG1, second motor generator MG2), power conversion devices (power conversion device 10, first inverter 11, second inverter 12, voltage conversion device 13) that exchange power with the motor generators, and a cooling device (cooling device 20) that cools the power conversion devices, a loss characteristic derivation unit (loss characteristic derivation unit 51) that derives, based on an operating condition of the motor generator, a loss characteristic (loss characteristic Lc) that represents a loss for each temperature of the power conversion device when the motor generator is operated under the operating condition; a thermal resistance derivation unit (thermal resistance derivation unit 53) that derives a thermal resistance (thermal resistance Rt) of the power conversion device when the power conversion device is cooled under the cooling conditions of the cooling device, based on the cooling conditions of the power conversion device; a thermal resistance characteristic derivation unit (thermal resistance characteristic derivation unit 54) that derives a thermal resistance characteristic (thermal resistance characteristic Rc) that represents an attained temperature for each loss of the power conversion device based on the loss characteristic derived by the loss characteristic derivation unit and the thermal resistance derived by the thermal resistance derivation unit; a saturation temperature / loss at saturation temperature derivation unit (saturation temperature / loss at saturation temperature derivation unit 55) that derives a saturation temperature (saturation temperature Tsat) that is the temperature reached by the power conversion device when the motor generator is operated under the operating conditions and the power conversion device is cooled under the cooling conditions, and a loss at saturation temperature (loss at saturation temperature PlsTsat) that is the loss of the power conversion device at the saturation temperature, based on the loss characteristic and the thermal resistance characteristic derived by the thermal resistance characteristic derivation unit; a moving body control unit (vehicle control unit 56) that controls the moving body based on the saturation temperature and / or the loss at saturation temperature derived by the saturation temperature / loss at saturation temperature derivation unit; A control device comprising:

[0225] According to (11), it is possible to derive the saturation temperature and the loss at saturation temperature when the motor generator is operated under predetermined operating conditions and the power conversion device is cooled under predetermined cooling conditions, so it is possible to control a moving object taking into account the saturation temperature and / or the loss at saturation temperature, which in turn can contribute to improving the energy efficiency of the moving object.

[0226] (12) A control program for causing a computer (control device 50) to execute predetermined processing to control a moving body (vehicle 1) including motor generators (first motor generator MG1, second motor generator MG2), power conversion devices (power conversion device 10, first inverter 11, second inverter 12, voltage conversion device 13) that exchange power with the motor generators, and a cooling device (cooling device 20) that cools the power conversion devices, The computer, Based on the operating conditions of the motor generator, a loss characteristic (loss characteristic Lc) representing a loss for each temperature of the power conversion device when the motor generator is operated under the operating conditions is derived (step Sp3); Based on the cooling conditions of the power conversion device by the cooling device, a thermal resistance (thermal resistance Rt) of the power conversion device when the power conversion device is cooled under the cooling conditions is derived (step Sp5); A thermal resistance characteristic (thermal resistance characteristic Rc) representing an attained temperature for each loss of the power conversion device is derived based on the loss characteristic and the thermal resistance (step Sp6); Based on the loss characteristics and the thermal resistance characteristics, a saturation temperature (saturation temperature Tsat) that is the temperature reached by the power conversion device when the motor generator is operated under the operating conditions and the power conversion device is cooled under the cooling conditions, and a loss at saturation temperature (loss at saturation temperature PlsTsat) that is the loss of the power conversion device at the saturation temperature are derived (step Sp7); Controlling the moving body based on the saturation temperature and / or the loss at saturation temperature (step Sp8); A control program that executes processing.

[0227] According to (12), it is possible to derive the saturation temperature and the loss at saturation temperature when the motor generator is operated under predetermined operating conditions and the power conversion device is cooled under predetermined cooling conditions, so it is possible to control a moving object taking into account the saturation temperature and / or the loss at saturation temperature, which in turn can contribute to improving the energy efficiency of the moving object. [Explanation of symbols]

[0228] 1. Vehicle (moving object) 10 Power conversion device 11 First inverter (power conversion device) 12 Second inverter (power conversion device) 13 Voltage conversion device (power conversion device) 20 Cooling device 21 Cooling circuit 22 Electric pump 35 Water temperature sensor 36 Device Temperature Sensor 36a First device temperature sensor 36b Second Device Temperature Sensor 36c Third Device Temperature Sensor 50 Control device 51 Loss characteristic derivation part 52 Flow rate derivation part 53 Thermal resistance lead part 54 Thermal resistance characteristic derivation section 55 Saturation temperature / Loss derivation section at saturation temperature 56 Vehicle control unit (mobile body control unit) CP intersection Lc loss characteristics PlsTsat Loss at saturation temperature RC thermal resistance characteristics Tsat saturation temperature

Claims

1. A control method executed by a computer for controlling a moving object including a motor generator, a power conversion device that exchanges electric power with the motor generator, and a cooling device that cools the power conversion device, comprising: The computer deriving loss characteristics representing losses for each temperature of the power conversion device when the motor generator is operated under operating conditions of the motor generator; deriving a thermal resistance of the power conversion device when the power conversion device is cooled under a cooling condition based on the cooling condition of the power conversion device by the cooling device; deriving a thermal resistance characteristic representing an attained temperature for each loss of the power conversion device based on the loss characteristic and the thermal resistance; deriving a saturation temperature, which is the temperature reached by the power conversion device when the motor generator is operated under the operating conditions and the power conversion device is cooled under the cooling conditions, and a loss at saturation temperature, which is the loss of the power conversion device when the saturation temperature is reached, based on the loss characteristics and the thermal resistance characteristics; controlling the moving body based on the saturation temperature and / or the loss at the saturation temperature; A method of control, which performs processing.

2. 2. The control method according to claim 1, The computer a loss of the power conversion device corresponding to an intersection of the loss characteristic and the thermal resistance characteristic on a plane having the loss of the power conversion device on one axis and the temperature of the power conversion device on the other axis is derived as the loss at saturation temperature, and the temperature of the power conversion device corresponding to the intersection is derived as the saturation temperature; Control method.

3. 3. The control method according to claim 1 or 2, The computer The loss characteristics are derived based on the operating conditions including the rotation speed and output torque of the motor generator and a voltage value of the electric power exchanged between the motor generator and the power conversion device. Control method.

4. 4. The control method according to claim 3, The computer deriving the loss characteristics when the voltage value is a predetermined first voltage value and when the voltage value is a predetermined second voltage value different from the first voltage value; deriving the saturation temperature and the loss at the saturation temperature when the first voltage value is set and when the second voltage value is set based on the loss characteristic and the thermal resistance characteristic; controlling the power conversion devices based on the respective losses at saturated temperature; Control method.

5. 3. The control method according to claim 1 or 2, the cooling device includes a cooling circuit through which cooling water circulates, and an electric pump that pumps the cooling water in the cooling circuit, the moving body includes a water temperature sensor that detects the temperature of the cooling water; The computer deriving, as the cooling condition, a flow rate of the cooling water pressure-fed by the electric pump per unit time based on the temperature of the cooling water detected by the water temperature sensor and a driving state of the electric pump; Deriving the thermal resistance based on the flow rate. Control method.

6. 6. The control method according to claim 5, The computer deriving the flow rate when the driving state of the electric pump is in a predetermined first state and when the driving state is in a predetermined second state different from the first state; deriving the thermal resistance when the first state is set and the thermal resistance when the second state is set based on the flow rates; deriving the saturation temperature and the loss at the saturation temperature for the first state and the second state based on the loss characteristic and the thermal resistance characteristic corresponding to each of the thermal resistances; controlling the electric pump based on each of the losses at saturated temperature; Control method.

7. 3. The control method according to claim 1 or 2, the moving object includes a device temperature sensor that detects the temperature of the power conversion device; The computer determining whether the device temperature sensor is abnormal based on the temperature of the power conversion device detected by the device temperature sensor and the saturation temperature; Control method.

8. 3. The control method according to claim 1 or 2, the cooling device includes a cooling circuit through which cooling water circulates, the moving body includes a water temperature sensor that detects the temperature of the cooling water, and a plurality of device temperature sensors that detect the temperature of the power conversion device; The computer determining whether the water temperature sensor is abnormal based on the temperatures of the power conversion devices detected by the device temperature sensors and the saturation temperature; Control method.

9. 3. The control method according to claim 1 or 2, the moving object includes a device temperature sensor that detects the temperature of the power conversion device; The computer determining a load state of the moving body based on the temperature of the power conversion device detected by the device temperature sensor and the saturation temperature, and controlling the moving body based on the determination result; Control method.

10. 3. The control method according to claim 1 or 2, the moving body includes a plurality of motor generators as the motor generators, The computer deriving the saturation temperature and the loss at the saturation temperature for each of the motor generators; Control method.

11. A control device for controlling a moving body including a motor generator, a power conversion device that exchanges electric power with the motor generator, and a cooling device that cools the power conversion device, a loss characteristic deriving unit that derives, based on an operating condition of the motor generator, a loss characteristic that represents a loss for each temperature of the power conversion device when the motor generator is operated under the operating condition; a thermal resistance derivation unit that derives, based on a cooling condition of the power conversion device by the cooling device, a thermal resistance of the power conversion device when the power conversion device is cooled under the cooling condition; a thermal resistance characteristic derivation unit that derives thermal resistance characteristics that represent an attained temperature for each loss of the power conversion device based on the loss characteristics derived by the loss characteristic derivation unit and the thermal resistance derived by the thermal resistance derivation unit; a saturation temperature / loss at saturation temperature derivation unit that derives a saturation temperature, which is the temperature reached by the power conversion device when the motor generator is operated under the operating conditions and the power conversion device is cooled under the cooling conditions, and a loss at saturation temperature, which is the loss of the power conversion device at the saturation temperature, based on the loss characteristic and the thermal resistance characteristic derived by the thermal resistance characteristic derivation unit; a mobile body control unit that controls the mobile body based on the saturation temperature and / or the loss at saturation temperature derived by the saturation temperature / loss at saturation temperature derivation unit; A control device comprising:

12. A control program for causing a computer to execute predetermined processing to control a moving body including a motor generator, a power conversion device that exchanges electric power with the motor generator, and a cooling device that cools the power conversion device, the control program comprising: The computer, deriving loss characteristics representing losses for each temperature of the power conversion device when the motor generator is operated under operating conditions of the motor generator; deriving a thermal resistance of the power conversion device when the power conversion device is cooled under a cooling condition based on the cooling condition of the power conversion device by the cooling device; deriving a thermal resistance characteristic representing an attained temperature for each loss of the power conversion device based on the loss characteristic and the thermal resistance; deriving a saturation temperature, which is the temperature reached by the power conversion device when the motor generator is operated under the operating conditions and the power conversion device is cooled under the cooling conditions, and a loss at saturation temperature, which is the loss of the power conversion device when the saturation temperature is reached, based on the loss characteristics and the thermal resistance characteristics; controlling the moving body based on the saturation temperature and / or the loss at the saturation temperature; A control program that executes processing.

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