Preheating control method and preheating control device

Abstract

The present application provides a preheating control method for preheating a vehicle-mounted device that is a preheating target by recovering waste heat from a motor unit including a motor and an inverter to preheat refrigerant circulating in a cooling circuit of a vehicle. In the preheating control method, a motor temperature, an inverter temperature, and a refrigerant temperature are obtained, a motor-refrigerant temperature difference, which is a difference between the motor temperature and the refrigerant temperature, and an inverter-refrigerant temperature difference, which is a difference between the inverter temperature and the refrigerant temperature, are calculated, and at least one of a current adjustment process for adjusting a current flowing to the motor unit and a frequency adjustment process for adjusting a frequency of the inverter is executed with reference to the motor-refrigerant temperature difference and the inverter-refrigerant temperature difference.

Description

Technical Field

[0001] The present invention relates to a preheating control method and a preheating control device for promoting the preheating of on-board equipment that is to be preheated in an electric vehicle having an electric motor unit including an electric motor and an inverter. Background Technology

[0002] JP2008-189249A discloses a cooling system that utilizes the heat generated by the driving of an electric motor and an inverter mounted on an electric vehicle to promote the preheating of on-board equipment (particularly batteries) in a cooling system shared with the electric motor and inverter. Summary of the Invention

[0003] In low-temperature environments requiring preheating, the temperature and flow rate of the refrigerant in the aforementioned cooling system are low, leading to increased thermal resistance. Consequently, the amount of heat transferred from the motor and inverter (motor unit), which become heat sources, to the cooling water decreases, increasing the thermal stress on the motor unit and raising concerns about its impact on strength and reliability.

[0004] Therefore, the purpose of this invention is to ensure the strength and reliability of the motor unit while promoting the preheating of the preheating target equipment.

[0005] According to one aspect of the present invention, a preheating control method is provided, which preheats on-board equipment that is to be preheated by circulating refrigerant in the cooling circuit of a vehicle and recovering waste heat from a motor unit including a motor and an inverter.

[0006] In this preheating control method, the motor temperature, inverter temperature, and refrigerant temperature are obtained, and the difference between the motor temperature and the refrigerant temperature (i.e., the motor-refrigerant temperature difference) and the difference between the inverter temperature and the refrigerant temperature (i.e., the inverter-refrigerant temperature difference) are calculated. Furthermore, referring to the motor-refrigerant temperature difference and the inverter-refrigerant temperature difference, at least one of the following is performed: current regulation processing to adjust the current flowing to the motor unit and frequency regulation processing to adjust the frequency of the inverter. Attached Figure Description

[0007] Figure 1 This is a block diagram showing the structure of a vehicle system implementing a preheating control method according to an embodiment of the present invention.

[0008] Figure 2 This is a flowchart illustrating the overall process in the preheating control method of this embodiment.

[0009] Figure 3 This is a flowchart illustrating the detailed process of the first current regulation.

[0010] Figure 4This is a flowchart illustrating the details of the second frequency adjustment process.

[0011] Figure 5 This is a flowchart illustrating the details of the first frequency adjustment process.

[0012] Figure 6 This is a flowchart illustrating the detailed process of the second current regulation. Detailed Implementation

[0013] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0014] Figure 1 This is a block diagram showing the structure of a vehicle system 10 that performs the preheating control method based on this embodiment.

[0015] in particular, Figure 1 The vehicle system 10 shown has an electric motor unit E mounted on an electric vehicle (electric vehicle or hybrid vehicle), a battery 32, a cooling circuit C (first cooling circuit C1 and second cooling circuit C2) for cooling them, and a controller 50 for controlling various devices.

[0016] The motor unit E is composed of a housing that integrally houses the motor 20 and the inverter 30, and has a cooling supply system (water jacket) for heat exchange with the motor 20 and the inverter 30 using cooling water.

[0017] The electric motor 20 functions as a driving source for an electric vehicle, and is particularly composed of a three-phase AC motor. Furthermore, the electric motor 20 is equipped with a device for detecting the temperature of the windings constituting the motor 20 (hereinafter referred to as "motor temperature T"). m The motor temperature sensor 60 is, for example, composed of a thermistor.

[0018] Inverter 30 controls the power supplied from battery 32 to motor 20. Specifically, inverter 30 has multiple semiconductor elements (IGBTs, etc.). Furthermore, these semiconductor elements are driven (turned on or off) according to switching command signals (duty cycle command signals) generated based on instructions from controller 50. Additionally, inverter 30 is equipped with a system for detecting the temperature of the elements within it (hereinafter referred to as "inverter temperature T"). i The inverter temperature sensor 61 is, for example, composed of a thermistor.

[0019] Battery 32 is a DC power source that functions as a drive power source for motor 20. For example, battery 32 may be configured as a high-voltage battery (drive battery) for vehicle use, such as a lithium-ion secondary battery.

[0020] The cooling circuit C has a first cooling circuit C1 that circulates cooling water supplied to the motor unit E and a second cooling circuit C2 that circulates cooling water supplied to the battery 32.

[0021] In the first cooling circuit C1, cooling water is circulated by driving the cooling water pump 41, thereby supplying refrigerant (cooling water) that undergoes heat exchange in the radiator 42 to the motor unit E. The output (cooling water flow rate) of the cooling water pump 41 is regulated by the controller 50. In particular, the controller 50 regulates the output of the cooling water pump 41 based on the required driving force of the electric vehicle and the preheating requirements (required heat) of the battery 32. Furthermore, a device for detecting the temperature of the cooling water (hereinafter referred to as "cooling water temperature T") is provided in the first cooling circuit C1 (particularly around the cooling water inlet of the motor unit E). w The cooling water temperature sensor 62.

[0022] In the second cooling circuit C2, cooling water is circulated by the cooling water pump 44, thereby supplying cooling water from the first cooling circuit C1 via the three-way valve 43 to the battery 32. The output of the cooling water pump 44 (cooling water flow rate) and the opening of the three-way valve 43 (the amount of cooling water flowing into the second cooling circuit C2) are regulated by the controller 50. In particular, the controller 50 adjusts the output of the cooling water pump 44 and the opening of the three-way valve 43 according to the preheating requirements (required heat) of the battery 32.

[0023] The controller 50 is an onboard computer that controls various devices mounted on the electric vehicle. Furthermore, the controller 50 can be composed of a single piece of hardware or multiple pieces of hardware. Typically, the controller 50 consists of a vehicle controller and a motor controller. The vehicle controller provides unified control over various parts of the electric vehicle, including the cooling water pump 41, the three-way valve 43, and the cooling water pump 44. The motor controller controls the operation of the motor unit E (specifically, the current I flowing into the motor unit E). E The frequency f of the inverter 30 is controlled so that they perform the processes described later in a distributed manner.

[0024] The controller 50 operates the motor unit E and each cooling actuator (cooling water pump 41, three-way valve 43 and cooling water pump 44) based on the occupant's operation of the accelerator pedal or the required driving force corresponding to the command from the autopilot controller and inputs from various sensors.

[0025] In particular, in scenarios where the controller 50 of this embodiment charges the battery 32 using an external charging device in a low-temperature environment, it recovers waste heat (especially heat generated by the motor 20 and inverter 30) from the motor unit E to preheat the battery 32, which is to be preheated. More specifically, when the controller 50 detects a preheating requirement for the battery 32, it operates each cooling actuator to circulate the cooling water in the cooling circuit C and adjusts the current I to the motor unit E. E The frequency f of the inverter 30.

[0026] Here, the following control is adopted: During the preheating process described above, the current I flowing to the motor unit E is controlled... E (The current I flowing into motor 20) m and the current I flowing to inverter 30 i The heat generated by the motor unit E is increased (set to a target value for preheating) to promote preheating. On the other hand, in low-temperature environments, the cooling water temperature T... w With low cooling water flow, the thermal resistance of the cooling water increases, and the amount of heat transferred from the motor unit E to the cooling water decreases. Therefore, the inventors focused on the following aspect: in conjunction with the increase in heat generation of the motor unit E, the temperature of the motor unit E (motor temperature T) m and / or inverter temperature T i ) and cooling water temperature T w The widening difference leads to increased thermal stress on the motor 20 and / or inverter 30.

[0027] In view of the above, the inventors have conceived of the following technical concept: In a scenario where preheating of vehicle-mounted equipment such as battery 32, which is to be preheated, is performed in a low-temperature environment, with reference to the motor temperature T... m With cooling water temperature T w The difference (hereinafter referred to as "motor cooling water temperature difference ΔT") mw ") and inverter temperature T i With cooling water temperature T w The difference (hereinafter referred to as "inverter cooling water temperature difference ΔT") iw ), executing the current I flowing in the opposite direction of the motor unit E. E The process of adjusting the current (hereinafter, appropriately referred to as "current regulation process") and / or adjusting the frequency f of the inverter 30 (hereinafter, appropriately referred to as "frequency regulation process") thereby protecting the motor unit E (motor 20 and inverter 30) and promoting preheating.

[0028] The above preheating control method is explained in detail below.

[0029] Figure 2This is a flowchart illustrating the preheating control method of this embodiment. Furthermore, it is envisioned that the preheating process performed on battery 32 occurs when charging is performed using a specified external charging device in a low-temperature environment. Figure 2 Each process. In particular, Figure 2 Each of the processes shown is initiated by the controller 50 based on the detection of preheating requirements.

[0030] exist Figure 2 In the preheating control method shown, in step S100, the controller 50 obtains the motor temperature T. m Measured values, inverter temperature T i The measured values ​​and cooling water temperature T w The measured value.

[0031] More specifically, controller 50 is used to measure the motor temperature T. m The measured value is obtained as a moving average of the detection values ​​of the motor temperature sensor 60 obtained at multiple sampling times. Furthermore, the moving average is calculated by applying a moving average filter to each of the acquired detection values. Additionally, the controller 50 uses the inverter temperature T... i The measured values ​​and cooling water temperature T w Similarly, the moving average values ​​of each detection value of the inverter temperature sensor 61 and the moving average values ​​of each detection value of the cooling water temperature sensor 62 are obtained respectively.

[0032] In step S110, the controller 50 determines the motor temperature T obtained in step S100. m Inverter temperature T i and cooling water temperature T w To calculate the temperature difference ΔT between the motor cooling water and the electric motor mw Temperature difference ΔT between inverter cooling water and inverter iw More specifically, controller 50 receives the motor temperature T. m Subtract cooling water temperature T w To calculate the temperature difference ΔT between the motor cooling water and the electric motor. mw Additionally, controller 50 receives data from the inverter temperature T. i Subtract cooling water temperature T w Calculate the inverter cooling water temperature difference ΔT iw .

[0033] In step S120, the controller 50 calculates the motor coolant temperature difference ΔT mw The value is compared with the predetermined value for the first motor. Here, the first motor is determined by the judgment value as the motor temperature T that is permissible from the viewpoint of achieving protection for motor 20. m With cooling water temperature T wThe maximum value of the difference. Furthermore, the first motor is predetermined to an appropriate value through experimentation or simulation using a judgment value.

[0034] Controller 50 measures the temperature difference ΔT between the motor cooling water and the water temperature. mw If the value used for the first motor is below the specified value (if step S120 is not specified), then the inverter cooling water temperature difference ΔT calculated in step S110 is further evaluated. iw The value is compared with the specified first inverter judgment value. Here, the first inverter judgment value is determined to be the inverter temperature T that is permissible from the viewpoint of protecting the inverter 30. i With cooling water temperature T w The maximum value of the difference. In addition, the first inverter is predetermined to an appropriate value through experimentation or simulation using a judgment value.

[0035] Then, the controller 50 measures the temperature difference ΔT between the motor cooling water and the water temperature. mw If the current exceeds the determination value for the first motor (if step S120 is yes), the first current adjustment process of step S140 is executed.

[0036] Figure 3 This is a flowchart illustrating the details of the first current regulation process. As shown in the figure, in the first current regulation process, in step S141, the controller 50, based on the determination result of step S120 above, adjusts the current I flowing to the motor unit E. E Reduce. More specifically, controller 50 determines the temperature difference ΔT between the motor cooling water and the actual temperature. m When the current exceeds the threshold set by the first motor, the current supplied from the external charging device to the motor unit E is reduced, thereby reducing the current I flowing to the motor unit E. E It is smaller than the target value used for basic preheating.

[0037] Therefore, in the motor cooling water temperature difference ΔT m In scenarios with a certain or greater scale (electric motor cooling water temperature difference ΔT) m In situations where there is no surplus heat, the heat generated by the motor 20 can be suppressed, thus protecting the motor 20.

[0038] Then, in step S142, as described above, the controller 50 controls the current I flowing to the motor unit E. E Under reduced conditions, the motor temperature T is obtained again. m The measured values ​​and cooling water temperature T w The measured value. More specifically, the controller 50 obtains the motor temperature T by performing the same calculation (moving average method) as in obtaining the measured values ​​in step S100. m The measured values ​​and cooling water temperature T wThe measured value.

[0039] In step S143, the controller 50 uses the motor temperature T obtained in step S142. m and cooling water temperature T w The motor cooling water temperature difference ΔT is calculated again using the same calculation as in step S110. mw .

[0040] In step S144, the controller 50 calculates the motor coolant temperature difference ΔT. mw The value is compared with the specified value for the second motor. Here, from the viewpoint of increasing heat generation within a range that can protect motor 20, the second motor is determined using a judgment value ΔT to judge the temperature difference ΔT between the motor cooling water and the motor. m Whether a certain surplus value was generated. In addition, the second motor is predetermined to an appropriate value through experiments or simulation using the judgment value.

[0041] Then, the controller 50 determines the temperature difference ΔT between the motor cooling water and the actual temperature. mw When the determination value for the second motor is below a certain value, the current I flowing to the motor unit E is... E Increase (step S145). More specifically, the controller 50 increases the current supplied from the external charging device to the motor unit E, etc., so that the current I flowing to the motor unit E... E It is larger than the reduced value after the processing in step S141.

[0042] In the first current regulation process described above, the current I reduced by the process in step S141 is utilized. E This is to protect the motor 20 and circulate the cooling water in the cooling circuit C, thereby heating the cooling water from the motor unit E, and raising the cooling water temperature T. w The temperature gradually increases. Therefore, the cooling water flow rate increases while the thermal resistance decreases, and the temperature difference ΔT between the motor cooling water and the ambient temperature rises. m Reduce (motor cooling water temperature difference ΔT) m (Close to 0). Furthermore, when determined by step S144, the temperature difference ΔT between the motor cooling water and the actual temperature is determined to be... m To fully reduce (motor cooling water temperature difference ΔT) m When a surplus is generated, in step S145, the current I is increased. E This increases the heat generation (heat recovery) of the motor unit E, which further promotes preheating.

[0043] Then, the controller 50 causes the current I flowing to the motor unit E to... E After the increase, the first frequency adjustment process of step S150 is executed.

[0044] Figure 4 This is a flowchart illustrating the details of the first frequency regulation process. As shown in the figure, in the first frequency regulation process, in step S151, the controller 50 again obtains the inverter temperature T. i The measured values ​​and cooling water temperature T w The measured value.

[0045] More specifically, the controller 50 uses the same calculation (moving average method) as in step S100 to obtain the measured values, and sets the inverter temperature T as the inverter temperature. i The measured values ​​and cooling water temperature T w The measured values ​​are obtained.

[0046] In step S152, the controller 50 uses the inverter temperature T obtained in step S151. i and cooling water temperature T w The inverter cooling water temperature difference ΔT is calculated again using the same method as in step S110. iw .

[0047] In step S153, the controller 50 applies the inverter cooling water temperature difference ΔT calculated in step S152. iw The value is compared with the first inverter's determination value mentioned above. Furthermore, the controller 50 determines the inverter cooling water temperature difference ΔT. iw If the determination value for the first inverter is below the value (if step S153 is not true), the processing in step S154 is executed.

[0048] In step S154, the controller 50 calculates the inverter cooling water temperature difference ΔT in step S152. iw Within a specified range below the second inverter's determination value, the frequency f of inverter 30 is increased. More specifically, controller 50 adjusts the inverter cooling water temperature difference ΔT of inverter 30. iw Feedback control adjusts the frequency f such that the difference between the second inverter's determination value and the value used by the second inverter is within a specified value. Here, the determination value for the second inverter is determined as the allowable inverter cooling water temperature difference ΔT within a range capable of protecting the inverter 30. iw The increase in margin (surplus). In addition, the second inverter is predetermined to an appropriate value through experimentation or simulation using a judgment value.

[0049] As described above, the current I increased by the process via step S150 E In scenarios where preheating is facilitated, the inverter cooling water temperature difference ΔT is determined through step S153. iwIf there is a certain surplus, the heat generation (heat recovery) of the motor unit E (especially the inverter 30) can be increased through the processing in step S154, which can further promote preheating.

[0050] Return to Figure 2 At the temperature difference ΔT between the motor cooling water and the water temperature m The first motor's judgment value is below the value and the inverter cooling water temperature difference ΔT iw If the value exceeds the first inverter's determination value (if step S120 is no and step S130 is yes), the controller 50 performs the second current regulation process in step 160 and the second frequency regulation process in step S170.

[0051] Figure 5 This is a flowchart illustrating the details of the second frequency regulation process. As shown in the figure, in the second frequency regulation process, in step S161, the controller 50 reduces the frequency f of the inverter 30. More specifically, the controller 50 reduces the frequency f of the inverter 30 by lowering it below a predetermined basic value (the predetermined frequency during preheating), etc.

[0052] Therefore, although the temperature difference ΔT between the motor cooling water and the water temperature m There is surplus, but the inverter cooling water temperature difference ΔT iw In situations where there is no surplus heat, the inverter 30 can be protected by suppressing its heat generation.

[0053] Furthermore, in the above-described step S161, it is preferable to reduce the frequency f and reduce the current I flowing to the motor unit E. E (especially the current I flowing into motor 20) m The target value for preheating is set above the specified value. Therefore, although the motor cooling water temperature difference ΔT... m There is a surplus, which can also suppress the decrease in preheating efficiency caused by reducing the heat generated by the motor 20.

[0054] Furthermore, when the frequency f of the inverter 30 is reduced, there is a concern that undesirable torque may be generated in the motor 20 due to decreased torque control accuracy, leading to vehicle vibration. Therefore, it is preferable to pre-apply a predetermined torque to the motor 20 when the electric vehicle stops, thereby shortening the gears of the drive system connected to the motor 20.

[0055] In step S162, the controller 50 obtains the inverter temperature T again by performing the same calculation (moving average method) as in step S100 for each measured value. i Measured values ​​and cooling water temperature T w The measured value.

[0056] In step S163, the controller 50 uses the inverter temperature T obtained in step S162. i and cooling water temperature T w The inverter cooling water temperature difference ΔT is calculated again using the same calculation as in step S110. iw .

[0057] In step S164, the controller 50 applies the inverter cooling water temperature difference ΔT calculated in step S163. iw The value is compared with the first inverter's determination value mentioned above. Furthermore, the controller 50 determines the inverter cooling water temperature difference ΔT. iw If the determination value for the first inverter is below the value (if step S164 is not true), the processing in step S165 is executed.

[0058] In step S165, the controller 50, similarly to step S154 above, calculates the inverter cooling water temperature difference ΔT in step S163. iw The frequency f of inverter 30 is increased when the value for the second inverter described above is below the specified value.

[0059] In the second frequency regulation process described above, the inverter 30 is protected by the frequency f reduced by the process in step S161, and the cooling water in the cooling circuit C is circulated, thereby heating the cooling water from the motor unit E, and the cooling water temperature T w The temperature gradually increases. Therefore, the cooling water flow rate increases while the thermal resistance decreases, and the inverter cooling water temperature difference ΔT... iw Reduce (inverter cooling water temperature difference ΔT) iw (Close to 0). Furthermore, when determined by step S164, the inverter cooling water temperature difference ΔT... iw To fully reduce (inverter cooling water temperature difference ΔT) iw When a surplus is generated, the frequency f is increased in step S165, thereby enabling the use of the inverter cooling water temperature difference ΔT. iw The excess capacity is used to increase the heat generation (heat recovery) of the motor unit E (especially the inverter 30), further promoting preheating.

[0060] Then, the controller 50 performs the second current regulation process of step S170 in parallel with the feedback control of the frequency f of the inverter 30 in step S165.

[0061] Figure 6This is a flowchart illustrating the details of the second current regulation process. As shown in the figure, in the second current regulation process, in step S171, the controller 50, in parallel with the feedback control of the frequency f of the inverter 30, obtains the motor temperature T again through the same calculation (moving average method) as in step S100 for obtaining each measured value. m Measured values ​​and cooling water temperature T w The measured value.

[0062] In step S172, the controller 50 uses the motor temperature T obtained in step S171. m and cooling water temperature T w The motor cooling water temperature difference ΔT is calculated again using the same method as in step S110. mw .

[0063] In step S173, the controller 50 calculates the motor coolant temperature difference ΔT. mw Compare with the determined value of the second motor.

[0064] Furthermore, when the temperature difference ΔT between the motor cooling water and the water temperature... mw When the value for determining the second motor is below the threshold (No in step S173), the controller 50 causes the current I flowing to the motor unit E to... E Add (step S174).

[0065] As described above, in the feedback control of the frequency f of the inverter 30, the temperature difference ΔT of the motor cooling water is determined via step S173. mw If there is a certain surplus, the heat generation (heat recovery) of the motor unit E (especially the motor 20) can be increased through the process of step S174, which can further promote preheating.

[0066] The structure and effects of the preheating control method of this embodiment described above will be explained.

[0067] According to this embodiment, a preheating control method is provided in which waste heat is recovered from a motor unit E containing a motor 20 and an inverter 30 in the vehicle's cooling circuit C (first cooling circuit C1 and second cooling circuit C2) to preheat on-board equipment (battery 32) that is to be preheated.

[0068] In this preheating control method, the motor temperature T is obtained. m Inverter temperature T i and refrigerant temperature (cooling water temperature T) w ), calculate the motor temperature T m The difference between the motor refrigerant temperature and the cooling water temperature Tw is the motor cooling water temperature difference ΔT.mw ), and inverter temperature T i With cooling water temperature T w The difference is the inverter refrigerant temperature difference (inverter cooling water temperature difference ΔT). iw Furthermore, referring to the temperature difference ΔT between the motor cooling water and the actual temperature. mw Temperature difference ΔT between inverter cooling water and inverter iw The current I flowing in the opposing motor unit E is executed. E At least one of the current regulation process (first current regulation process and second current regulation process) for regulating the current (first frequency regulation process and second frequency regulation process) and the frequency regulation process (first frequency regulation process and second frequency regulation process) for regulating the frequency f of the inverter 30.

[0069] Therefore, by referring to the temperature difference ΔT between the motor cooling water and the electric motor mw Temperature difference ΔT between inverter cooling water and inverter iw Appropriately adjust the current I flowing to the motor unit E. E The current Im flowing to the motor 20 and the current Ii flowing to the inverter 30, and / or the frequency f of the inverter 30, can regulate the heat generated by the motor 20 and the inverter 30 (heat recovery). Therefore, component protection of the motor unit E composed of the motor 20 and the inverter 30 can be achieved, and preheating of the on-board equipment can be promoted.

[0070] In particular, through in-depth research, the inventors discovered that the strength limits of the components of the motor 20 and the inverter 30 are respectively related to the motor temperature T. m and inverter temperature T i Compared to themselves, and with cooling water temperature T w The difference is more strongly correlated. Therefore, by referring to the temperature difference ΔT of the motor cooling water... mw and the temperature difference ΔT between the inverter cooling water iw It can appropriately estimate the range within which the motor 20 and inverter 30 have not reached the strength limit, and within this range, it can increase the recovery of heat as much as possible to improve the preheating efficiency.

[0071] In particular, the aforementioned current regulation process includes a first current regulation process (step S140), which is based on the temperature difference ΔT between the motor cooling water and the current regulation process. mw If the current exceeds the predetermined value for the first motor, a first current regulation process is performed (steps S120 and S141). Furthermore, in the first current regulation process, the current I flowing through the motor unit E is adjusted... E reduce.

[0072] Therefore, in the motor cooling water temperature difference ΔT mw In the absence of excess heat, the heat generated by the motor 20 can be reduced, thus prioritizing the protection of the motor 20.

[0073] More specifically, in the first current regulation process, the current I flowing to the motor unit E is... E Under conditions of reduced cooling water circulation, the motor temperature T is obtained again. m and cooling water temperature T w (Step S142). Then, based on the obtained motor temperature T m and cooling water temperature T w Calculate the motor cooling water temperature difference ΔT again. mw (Step S143). Furthermore, when the temperature difference ΔT between the motor cooling water and the water temperature... mw When the specified value for the second motor is below the threshold value, the current I flowing to the motor unit E is... E Add (No to step S144 and step S145).

[0074] Therefore, when the current I E Under reduced conditions, it can accurately detect the temperature difference ΔT between the motor cooling water and the ambient temperature. mw This creates a surplus condition, under which the current I... E Increase. Therefore, it is possible to increase the heat generation (heat recovery) as much as possible within the range of achieving protection for motor 20, thereby further improving the preheating efficiency.

[0075] Furthermore, the aforementioned frequency regulation process includes a first frequency regulation process, which adjusts the current I flowing to the motor unit E. E When the frequency is increased (step S145), a first frequency adjustment process is performed (step S150). Then, in the first frequency adjustment process, the current I flowing to the motor unit E is adjusted. E Under the increased conditions, the inverter temperature T is obtained again. i and cooling water temperature T w (Step S151) Based on the obtained inverter temperature T i and cooling water temperature T w Calculate the inverter cooling water temperature difference ΔT again. iw (Step S152). Furthermore, when the inverter cooling water temperature difference ΔT iw When the specified first inverter judgment value is below the value, the inverter cooling water temperature difference ΔT iw The frequency f of inverter 30 is increased within the range below the specified second inverter determination value (No in step S153 and step S154).

[0076] Therefore, it is possible to make the current I flowing to the motor unit E E Under the increased conditions, the inverter cooling water temperature difference ΔT is further utilized. iwThe excess capacity is used to increase heat generation. Therefore, the heat generation (heat recovery) can be increased as much as possible within the range that can achieve component protection of motor unit E, thereby further improving the preheating efficiency.

[0077] Furthermore, the aforementioned frequency adjustment process includes a second frequency adjustment process (step S160), which adjusts the frequency based on the temperature difference ΔT between the motor cooling water and the motor. mw The first motor is below the specified judgment value and the inverter cooling water temperature difference ΔT iw If the first inverter's set value is exceeded (if step S120 is negative and step S130 is positive), a second frequency adjustment process is performed. Then, in the second frequency adjustment process, the frequency f of the inverter 30 is reduced (step S161).

[0078] Therefore, although the temperature difference ΔT between the motor cooling water and the water temperature m There is surplus, but the inverter cooling water temperature difference ΔT iw In scenarios where there is no margin of safety (such as scenarios where inverter 30 needs protection), the frequency f can be reduced to suppress the heat generation of inverter 30, thus prioritizing the protection of inverter 30.

[0079] More specifically, in the second frequency regulation process, while reducing the frequency f of inverter 30 and circulating the cooling water, the inverter temperature T is obtained again. i and cooling water temperature T w (Step S162) Based on the obtained inverter temperature T i and cooling water temperature T w Calculate the inverter cooling water temperature difference ΔT again. iw (Step S163). Furthermore, when the inverter cooling water temperature difference ΔT iw When the value used to determine the first inverter is below the threshold, the temperature difference ΔT between the inverter's cooling water and the threshold value is... iw The frequency f of inverter 30 is increased within the range below the specified second inverter determination value (No in step S164 and step S165).

[0080] Therefore, by reducing the frequency f of inverter 30, the inverter cooling water temperature difference ΔT can be accurately detected. iw This creates a surplus condition, under which the frequency f increases. Therefore, it is possible to maximize heat generation (heat recovery) within the range of achieving the protection of inverter 30, thereby further improving preheating efficiency.

[0081] Furthermore, the aforementioned current regulation process includes a second current regulation process (step S170), in which the frequency f of the inverter 30 is adjusted while performing the second current regulation process (steps S165 and S171). Then, in the second current regulation process, the motor temperature T is obtained again.m and cooling water temperature T w (Step S171), based on the obtained motor temperature T m and cooling water temperature T w Calculate the motor cooling water temperature difference ΔT again. mw (Step S172). Then, when the temperature difference ΔT between the motor cooling water and the temperature... mw When the current I flowing to motor unit E is below the specified motor determination value (second motor determination value) (step S173 is no), the current I flowing to motor unit E is... E Add (step S174).

[0082] Therefore, by increasing the frequency f of inverter 30, the temperature difference ΔT between the motor cooling water and the actual temperature can be accurately detected. mw A surplus condition is created, under which the current I flowing to the motor unit E is increased. E Increase. Therefore, it is possible to increase the heat generation (heat recovery) as much as possible within the range of achieving protection for motor 20, thereby further improving the preheating efficiency.

[0083] In addition, in this embodiment, the motor temperature T m Inverter temperature T i and cooling water temperature T w These values ​​are obtained as moving averages of the sensor values ​​obtained over a specified sampling time.

[0084] Therefore, the temperature difference ΔT between the motor cooling water and the motor can be calculated with higher accuracy. mw and the temperature difference ΔT between the inverter cooling water iw This improves the accuracy of determinations based on these determinations related to the necessity of protecting the motor 20 and / or inverter 30.

[0085] Furthermore, in this embodiment, a controller 50 is provided that functions as a preheating control device suitable for performing the above-described preheating control method. In particular, the controller 50 includes an acquisition unit that acquires the motor temperature T. m Inverter temperature T i and refrigerant temperature (cooling water temperature T) w The calculation unit calculates the motor temperature T. m With cooling water temperature T w The difference is the temperature difference of the refrigerant in the motor (the temperature difference of the cooling water in the motor ΔT). mw ), and inverter temperature T i With cooling water temperature T w The difference is the inverter refrigerant temperature difference (inverter cooling water temperature difference ΔT). iw The regulating and processing unit refers to the temperature difference ΔT between the motor cooling water and the temperature of the motor cooling water. mwand the inverter cooling water temperature difference ΔT iw The current I flowing in the opposing motor unit E is executed. E At least one of the following: current regulation processing (first current regulation processing and second current regulation processing) for regulating the current (first frequency regulation processing and second frequency regulation processing) and frequency regulation processing (first frequency regulation processing and second frequency regulation processing) for regulating the frequency f of the inverter 30.

[0086] The processing steps described above illustrate one example for implementing each embodiment. The order of some of the processing steps can be changed within the scope of implementing each embodiment, and some of the processing steps can be omitted or other processing steps can be added.

[0087] Furthermore, each process shown in each embodiment is executed based on a program for causing a computer to perform each process step. Therefore, each embodiment can also be understood as an embodiment of a program that performs the functions of these processes and a recording medium that stores the program.

[0088] The embodiments of each invention have been described above, but the above embodiments only show a part of the application examples of the present invention, and the technical scope of the present invention is not limited to the specific structure of the above embodiments.

Claims

1. A preheating control method for preheating on-board equipment by circulating refrigerant in the vehicle's cooling circuit and recovering waste heat from a motor unit including an electric motor and an inverter, characterized in that... Obtain the motor temperature, inverter temperature, and refrigerant temperature. Calculate the difference between the motor temperature and the refrigerant temperature, i.e., the motor-refrigerant temperature difference, and the difference between the inverter temperature and the refrigerant temperature, i.e., the inverter-refrigerant temperature difference. Referring to the refrigerant temperature difference of the motor and the refrigerant temperature difference of the inverter, at least one of the following is performed: current regulation processing to regulate the current flowing to the motor unit and frequency regulation processing to regulate the frequency of the inverter.

2. The preheating control method according to claim 1, characterized in that, The current regulation process includes a first current regulation process. If the temperature difference between the refrigerant and the motor exceeds a predetermined first motor-specific threshold, the first current regulation process is executed. In the first current regulation process, the current flowing to the motor unit is reduced.

3. The preheating control method according to claim 2, characterized in that, In the first current regulation process With the current flowing to the motor unit reduced and the refrigerant circulated, the motor temperature and the refrigerant temperature are obtained again. Based on the obtained motor temperature and refrigerant temperature, the motor-refrigerant temperature difference is calculated again. When the temperature difference between the refrigerant and the motor is below a predetermined value for the second motor, the current flowing to the motor unit is increased.

4. The preheating control method according to claim 3, characterized in that, The frequency adjustment process includes a first frequency adjustment process. When the current flowing to the motor unit is increased, the first frequency regulation process is executed. In the first frequency adjustment process With the current flowing to the motor unit increased, the inverter temperature and the refrigerant temperature are obtained again. Based on the obtained inverter temperature and refrigerant temperature, the inverter-refrigerant temperature difference is calculated again. When the inverter refrigerant temperature difference is below a predetermined first inverter determination value, the frequency of the inverter is increased within the range where the inverter refrigerant temperature difference is below a predetermined second inverter determination value.

5. The preheating control method according to claim 1, characterized in that, The frequency adjustment process includes a second frequency adjustment process. If the refrigerant temperature difference of the electric motor is below a predetermined first motor-use judgment value and the refrigerant temperature difference of the inverter exceeds a predetermined first inverter-use judgment value, the second frequency regulation process is executed. In the second frequency regulation process, the frequency of the inverter is reduced.

6. The preheating control method according to claim 5, characterized in that, In the second frequency adjustment process With the inverter frequency reduced and the refrigerant circulated, the inverter temperature and the refrigerant temperature are obtained again. The inverter refrigerant temperature difference is recalculated based on the obtained inverter temperature and refrigerant temperature. When the inverter refrigerant temperature difference is below the first inverter determination value, the frequency of the inverter is increased within the range where the inverter refrigerant temperature difference is below the predetermined second inverter determination value.

7. The preheating control method according to claim 6, characterized in that, The current regulation process includes a second current regulation process. While adjusting the frequency of the inverter, the second current regulation process is performed. In the second current regulation process The motor temperature and the refrigerant temperature are obtained again. Based on the obtained motor temperature and refrigerant temperature, the motor-refrigerant temperature difference is calculated again. The current flowing to the motor unit is increased when the temperature difference between the refrigerant and the motor is below a predetermined value for motor use.

8. The preheating control method according to any one of claims 1 to 7, characterized in that, The motor temperature, the inverter temperature, and the refrigerant temperature are obtained as moving averages of the sensor values ​​obtained at multiple sampling times.

9. A preheating control device that preheats onboard equipment by circulating refrigerant in the vehicle's cooling circuit and recovering waste heat from a motor unit including an electric motor and an inverter, characterized in that... The preheating control device has the following features: The acquisition unit acquires the motor temperature, inverter temperature, and refrigerant temperature. The calculation unit calculates the difference between the motor temperature and the refrigerant temperature, i.e., the motor-refrigerant temperature difference, and the difference between the inverter temperature and the refrigerant temperature, i.e., the inverter-refrigerant temperature difference. The regulation processing unit, with reference to the refrigerant temperature difference of the motor and the refrigerant temperature difference of the inverter, performs at least one of current regulation processing to regulate the current flowing to the motor unit and frequency regulation processing to regulate the frequency of the inverter.

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