Warm-up control method and warm-up control device

Abstract

The present invention provides a warm-up control method for an electric vehicle that has an electric powertrain that includes an inverter and a rotary electric machine, wherein a d-axis current is made to flow through the rotary electric machine while the rotation of the rotary electric machine is stopped, and heat produced at the electric powertrain by the flow of the d-axis current is used to warm up a prescribed target apparatus that is installed on the electric vehicle. One warm-up position from among a plurality of warm-up positions that maximize the sum of phase currents for making the d-axis current flow is selected, the rotary electric machine is rotated to the selected warm-up position, and the d-axis current is made to flow at the selected warm-up position. The warm-up position at which the d-axis current is made to flow is repeatedly changed while the target apparatus is warmed up.

Description

Warm-up control method and warm-up control device

[0001] The present invention relates to a warm-up control method and a warm-up control device for warming up a predetermined target device mounted on an electric vehicle.

[0002] JP6468401B discloses a temperature abnormality detection device for a power conversion device that determines that a temperature abnormality has occurred when the difference between the temperature of the power conversion unit and the temperature of the cooling fluid is greater than a difference threshold value and the temperature of the power conversion unit is higher than a preset power conversion unit temperature threshold value.

[0003] An electric vehicle includes an electric powertrain that includes an inverter and a rotating electric machine. In recent electric vehicles, heat generated in the electric powertrain may be used to warm up certain target devices mounted on the electric vehicle. For example, by maintaining the q-axis current at zero and passing a d-axis current, the inverter and the rotating electric machine generate heat while the rotating electric machine is stopped from rotating. The generated heat is then transported to warm up a cold battery or other device in the electric vehicle.

[0004] In this warm-up control that uses heat generated in the electric powertrain by the d-axis current, the temperature of the switching elements included in the inverter is likely to reach the heat resistance temperature (upper limit temperature). Therefore, the heat resistance temperature of the switching elements essentially limits the amount of heat generated per unit time in the electric powertrain. Therefore, in warm-up control that uses heat generated in the electric powertrain by the d-axis current, the heat resistance temperature of the switching elements becomes a bottleneck, and the time required to complete warm-up of the target equipment is lengthened.

[0005] The present invention aims to provide a warm-up control method and a warm-up control device that, when warming up a battery or the like using heat generated in an electric powertrain by a d-axis current, can improve the amount of heat generated per unit time in an electric powertrain and complete warm-up of the target equipment more quickly than before.

[0006] One aspect of the present invention is a warm-up control method for an electric vehicle having an electric powertrain including an inverter and a rotating electric machine, in which a d-axis current is passed through the rotating electric machine when the rotating electric machine is stopped, and heat generated in the electric powertrain by the d-axis current is used to warm up a predetermined target device mounted on the electric vehicle. In this warm-up control method, one warm-up position is selected from multiple warm-up positions that maximize the total amount of phase current for passing the d-axis current, the rotating electric machine is rotated to the selected warm-up position, and the d-axis current is passed at the selected warm-up position. Then, while warming up the target device, the warm-up position through which the d-axis current is passed is repeatedly changed.

[0007] FIG. 1 is an explanatory diagram showing a schematic configuration of an electric vehicle. FIG. 2 is a block diagram showing the configuration of a controller. FIG. 3 is a flowchart related to warm-up control. FIG. 4 is a graph showing phase currents and warm-up positions for flowing d-axis current. FIG. 5 is a graph schematically showing changes in switching element temperature. FIG. 6 is a graph showing changes in torque when changing a warm-up position. FIG. 7 is a flowchart related to limiting the torque rate when changing a warm-up position. FIG. 8 is a flowchart related to selecting a destination when changing a warm-up position. FIG. 9 is a flowchart related to selecting a destination when changing a warm-up position. FIG. 10 is a flowchart related to adjusting a switching frequency. FIG. 11 is a flowchart related to initial setting of a switching frequency. FIG. 12 is a flowchart related to adjusting a d-axis current. FIG. 13 is a flowchart related to initial setting of a d-axis current.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] 1 is an explanatory diagram showing a schematic configuration of an electric vehicle 100. The electric vehicle 100 is an electric vehicle, a hybrid vehicle, or the like. As shown in FIG. 1 , the electric vehicle 100 includes a battery 10, an electric powertrain 11, a cooling circuit 12, and a controller 13.

[0010] The battery 10 is a DC power source that stores power for driving the electric vehicle 100. The battery 10 is configured, for example, as a lithium ion battery or the like, and is rechargeable. The battery 10 is charged by an external power source or an on-board power generation system (neither of which is shown). The battery 10 can also be charged by regenerative power input from the electric powertrain 11. The available output power (DC voltage V ｄｃ ), temperature (hereinafter referred to as battery temperature T ｂａｔ Parameters representing the state of the battery 10, such as the charge rate (hereinafter referred to as "charge rate"), the SOC (State of Charge) representing the charging rate, and the acceptable power, can be detected as appropriate using a sensor (not shown) or obtained as appropriate by calculation.

[0011] The performance of the battery 10 is determined by the battery temperature T ｂａｔ For example, the battery temperature T ｂａｔ When the battery 10 is in a low temperature state that is lower than a predetermined appropriate temperature range, the outputtable power and the receivable power of the battery 10 decrease. Therefore, when the battery 10 is used or charged in a low temperature state, the battery 10 is warmed up and the battery temperature T ｂａｔ It is necessary to raise the battery temperature T ｂａｔ For the threshold (hereinafter, the lower limit T ｂａｔ－ｌｉｍ ) is set, and the battery temperature T ｂａｔ is the lower limit T ｂａｔ－ｌｉｍ When the battery 10 is used or when the battery 10 is charged, the battery 10 is warmed up. ｂａｔ－ｌｉｍ is preset to, for example, the minimum value of the appropriate temperature range or a value close to it.

[0012] The electric powertrain 11 is a system that generates driving force for the electric vehicle 100 using electric power supplied from the battery 10. The electric powertrain 11 includes, for example, a rotating electric machine 16 and an inverter 17. The electric powertrain 11 is also used to warm up target devices mounted on the electric vehicle 100. In this embodiment, the electric powertrain 11 is used to warm up the battery 10 when the rotation of the rotating electric machine 16 is stopped. The electric powertrain 11 also includes components (not shown) such as gears and drive shafts for transmitting the torque T generated by the rotating electric machine 16.

[0013] The rotating electric machine 16 is a motor or a generator. In this embodiment, the rotating electric machine 16 is a motor and serves as a drive source for the electric vehicle 100. The rotating electric machine 16 is, for example, an IPM (Interior Permanent Magnet) type three-phase AC synchronous motor having three phases, UVW. The operation of the rotating electric machine 16 is controlled by a so-called d-axis current i ｄ and q-axis current i ｑ The d-axis current i ｄ and q-axis current i ｑ is the current in a coordinate system that rotates together with the rotor (not shown) in which permanent magnets are embedded. The d-axis current i ｄ corresponds to the magnetic flux generated by the stator coils of the U, V and W phases, and the q-axis current i ｑ corresponds to the torque T (driving force) generated by the rotating electrical machine 16. Therefore, the q-axis current i ｑ is kept to zero, the d-axis current i ｄ In this embodiment, this property is utilized, and when warming up the battery 10, the d-axis current i is set to 0 so as not to rotate the rotating electric machine 16. ｄ is washed away.

[0014] The current i flowing through each phase of UVW Ｕ , i Ｖ , i Ｗ (Hereinafter, phase current i ＵＶＷ ), the temperature T ＭＧThe rotational position θ of the rotating electrical machine 16 (the position or orientation of the rotor) and the like are measured appropriately by various sensors (not shown). ＭＧ is the maximum value of the temperatures of the windings of each phase and the permanent magnets, etc. In this embodiment, the rotational position θ of the rotating electric machine 16 is expressed by an electrical angle. In the following, the rotational position θ when the rotating electric machine 16 stops rotating due to the electric vehicle 100 being stopped is referred to as the stop position θ. ｓｔｏｐ In addition, the d-axis current i ｄ and q-axis current i ｑ is the phase current i ＵＶＷ The heat resistance temperature T ＭＧ－ｌｉｍ (Upper limit temperature) is a parameter known through experiments, simulations, or the like.

[0015] The inverter 17 converts DC power supplied from the battery 10 into AC power and supplies it to the rotating electric machine 16. This drives (rotates) the rotating electric machine 16. Furthermore, when the rotating electric machine 16 is rotated by the electric vehicle 100, the inverter 17 converts regenerative AC power output from the rotating electric machine 16 into DC power and inputs it to the battery 10. This charges the battery 10.

[0016] The inverter 17 is configured using a plurality of switching elements (UP, UN, VP, VN, WP, WN). UP and UN are switching elements that respectively configure the upper and lower arms of the U phase. VP and VN are switching elements that respectively configure the upper and lower arms of the V phase. Similarly, WP and WN are switching elements that respectively configure the upper and lower arms of the W phase. The switching elements UP-WN include, for example, transistors such as an insulated gate bipolar transistor (IGPT) or a metal-oxide-semiconductor field-effect transistor (MOSFET), and a freewheeling diode.

[0017] When rotating the rotating electric machine 16, the switching elements UP-WN are used almost equally.ＳＷ = {T ＵＰ , T ＵＮ , T ＶＰ , T ＶＮ , T ＷＰ , T ＷＮ} is generally uniform.

[0018] On the other hand, in order to warm up the battery 10, the d-axis current i ｄ When the phase current i flows, some of the switching elements UP-WN ＵＶＷ Therefore, the temperature T of the switching element UP-WN ＳＷ In particular, the maximum phase current i ＵＶＷ The temperature of a specific switching element through which ＳＷ－ｌｉｍ Therefore, the d-axis current i ｄ When the battery 10 is warmed up by energizing the ＰＴ is substantially the heat resistance temperature T ＳＷ－ｌｉｍ is limited by

[0019] In this embodiment, the temperature T ＳＷ = {T ＵＰ , T ＵＮ , T ＶＰ , T ＶＮ , T ＷＰ , T ＷＮ} can be measured appropriately by a temperature sensor (not shown). ＳＷ－ｌｉｍ is a parameter known by experiment, simulation, or the like.

[0020] Switching frequency f of switching element UP-WN ＳＷ In this embodiment, the basic switching frequency f ＳＷ (Hereinafter, the fundamental frequency f ｉｎｉ Therefore, the switching elements UP-WN are, in principle, driven at a fundamental frequency f ｉｎｉ However, when certain conditions are met, the switching frequency fＳＷ is the fundamental frequency f ｉｎｉ (hereinafter referred to as high frequency f Ｈ ), or the fundamental frequency f ｉｎｉ (hereinafter referred to as low frequency f Ｌ is changed to "(

[0021] The cooling circuit 12 cools the battery 10, the electric powertrain 11, and the like by circulating a refrigerant such as coolant (hereinafter simply referred to as coolant) through the battery 10, the electric powertrain 11, and other components that require cooling. When warming up the battery 10, the cooling circuit 12 exchanges heat with the electric powertrain 11 and circulates the coolant, whose temperature has increased, through the battery 10, and the like. As a result, heat generated in the electric powertrain 11 is transported to the battery 10, and the like. In this embodiment, when warming up of the battery 10 is required, the cooling circuit 12 circulates the coolant through the battery 10 and the electric powertrain 11. As a result, the cooling circuit 12 cools the battery 10 and the electric powertrain 11 in response to the d-axis current i ｄ The heat generated in the electric power train 11 by the current flow is transported to the battery 10, and the battery temperature T ｂａｔ Increases.

[0022] The temperature of the cooling water (hereinafter referred to as the cooling water temperature T Ｗ The temperature of the cooling water can be measured by a sensor (not shown) as needed. The flow rate of the cooling water can be adjusted. In this embodiment, when the battery 10 is warmed up, the flow rate of the cooling water is adjusted based on the cooling water temperature T Ｗ Specifically, in a scene where the battery 10 is warmed up, the cooling water temperature T Ｗ When the cooling water temperature T Ｗ When the temperature drops, the flow rate of the cooling water is reduced accordingly. The flow rate of the cooling water is adjusted by changing the output of a cooling water circulation pump (not shown) that circulates the cooling water.

[0023] The controller 13 is a control device that comprehensively controls each part of the electric vehicle 100. The controller 13 is configured, for example, by one or more computers, and is programmed to control each part of the electric vehicle 100 at a predetermined control cycle.

[0024] In particular, the controller 13 is configured to function as a warm-up control device that warms up a predetermined target device that is in a low temperature state using the electric powertrain 11. ｂａｔ is the lower limit T ｂａｔ－ｌｉｍ When the battery 10 is in a low temperature state, the controller 13 supplies the d-axis current i ｄ By passing the current through the electric power train 11, heat is generated in the electric power train 11, and the generated heat is used to warm up the battery 10.

[0025] 2 is a block diagram showing the configuration of the controller 13. Here, the configuration of the controller 13 related to the warm-up control of the battery 10 and the like will be described, and the description of the other parts will be omitted.

[0026] As shown in FIG. 2, the controller 13 includes a warm-up necessity determining unit 21 , a rotational position control unit 22 , a current control unit 23 , a frequency control unit 24 , and a flow rate adjusting unit 25 .

[0027] The warm-up necessity determination unit 21 determines whether warm-up is necessary. In this embodiment, the warm-up necessity determination unit 21 determines whether warm-up is necessary based on the battery temperature T ｂａｔ The lower limit T ｂａｔ－ｌｉｍ Then, the warm-up necessity determining unit 21 compares the battery temperature T ｂａｔ is the lower limit T ｂａｔ－ｌｉｍ When the battery 10 is in a low temperature state, it is determined that the battery 10 needs to be warmed up.

[0028] The rotational position control unit 22 adjusts or changes the rotational position (electrical angle) θ of the rotating electrical machine 16 when warming up the battery 10. Specifically, the rotational position control unit 22 adjusts or changes the d-axis current i ｄ Phase current i for flowing ＵＶＷ The total amount (|i Ｕ |+|i Ｖ |+|i ＷThe rotating electric machine 16 is rotated so as to reach a rotational position θ (hereinafter referred to as a warm-up position) at which the rotational angle θ is maximized. However, there are multiple rotational positions that can be used as the warm-up position. Specifically, θ １ -θ ６ Six warm-up positions θ ｎ (n=1-6).

[0029] In this embodiment, the rotational position control unit 22 determines the stop position θ of the rotating electric machine 16. ｓｔｏｐ Based on this, multiple warm-up positions θ ｎ , one warm-up position (hereinafter referred to as the initial position) to be used when starting to warm up the battery 10. Specifically, the rotational position control unit 22 selects one warm-up position (hereinafter referred to as the initial position) from the stop position θ ｓｔｏｐ The warm-up position θ closest to ｎ is selected as the initial position. Then, at least until the warm-up of the battery 10 starts, the rotational position control unit 22 sets the rotating electrical machine 16 to the stop position θ ｓｔｏｐ Therefore, when the warm-up of the battery 10 is started, the d-axis current i ｄ is energized.

[0030] In this embodiment, after starting the warm-up of the battery 10, the rotational position control unit 22 rotates the rotating electric machine 16 to set the warm-up position θ ｎ Specifically, while the battery 10 is being warmed up, the rotational position control unit 22 changes the d-axis current i ｄ Warm-up position θ used to flow ｎ Repeatedly change.

[0031] The rotation position θ is adjusted to the initial position, or the warm-up position θ ｎ When the rotating electric machine 16 is rotated to change the rotational position θ, the rotating electric machine 16 generates a torque T. Therefore, in this embodiment, when adjusting or changing the rotational position θ, the rotational position control unit 22 limits the torque T of the rotating electric machine 16 and the time rate of change of the torque T (hereinafter referred to as the torque rate).

[0032] In this embodiment, the warm-up position θ ｎ The warm-up position θ ｎ and the d-axis current iｄ That is, at the warm-up position θ ｎ and the d-axis current i ｄ The time to flow is t α (not shown), and the warm-up position θ ｎ The time required to change β (not shown), then t α >t β and the warm-up position θ ｎ is continually changed.

[0033] However, warm-up position θ ｎ The d-axis current i ｄ The time for which the ｎ That is, the time required to change t α <t β and the warm-up position θ ｎ may be varied almost continuously.

[0034] In this embodiment, the warm-up position θ ｎ When the warm-up position θ is changed, the rotating electric machine 16 is rotated in a certain direction. For example, when the rotating electric machine 16 is rotated in the forward direction (the direction in which the rotational position θ increases) and adjusted to the initial position, ｎ When the rotational position θ is changed, the rotating electric machine 16 is rotated in the positive direction. When the rotating electric machine 16 is rotated in the negative direction (the direction in which the rotational position θ is decreased) and adjusted to the initial position, the rotating electric machine 16 is rotated in the positive direction. ｎ When the rotational direction of the rotating electric machine 16 is changed, the rotating electric machine 16 is rotated in the negative direction.

[0035] However, warm-up position θ ｎ When changing the warm-up position θ, the rotating electric machine 16 may be rotated in the reverse direction relative to the previous rotation direction. ｎ When this happens, next, the warm-up position θ ｎ When changing the warm-up position θ , the rotating electric machine 16 may be rotated in the negative direction. ｎ When this happens, next, the warm-up position θ ｎ When changing the rotational direction, the rotating electrical machine 16 may be rotated in the forward direction.

[0036] The current control unit 23 is configured to control the battery 10 and the like to be warmed up. ｎ When this is the case, the d-axis current i ｄ In this embodiment, the current control unit 23 generates heat by supplying a d-axis current i ｄ (Hereinafter, basic d-axis current i ｄ－ｉｎｉ (This is called "the sound of a bell").

[0037] However, the current control unit 23 is configured to control the temperature T ＳＷ , T ＭＧ Based on this, the d-axis current i ｄ The basic d-axis current i ｄ－ｉｎｉ High d-axis current i ｄＨ That is, the temperature T ＳＷ , T ＭＧ is low, and the d-axis current i ｄ Even if the temperature is increased, the switching element UP-WN and the rotating electrical machine 16 do not exceed the heat resistance temperature T ＳＷ－ｌｉｍ , T ＭＧ－ｌｉｍ When it is difficult to reach the d-axis current i ｄ The basic d-axis current i ｄ－ｉｎｉ From high d-axis current i ｄＨ may increase to.

[0038] Also, warm-up position θ ｎ Even if the temperature T of the switching element UP-WN is repeatedly changed, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ If it is expected that the d-axis current i ｄ The basic d-axis current i ｄ－ｉｎｉ The low d-axis current i ｄＬ may be changed to.

[0039] The current control unit 23 supplies the d-axis current i ｄ The phase current i ＵＶＷ More specifically, the d-axis current i ｄThe current control unit 23 generates a PWM (Pulse Width Modulation) signal that switches the switching elements UP-WN so that a phase current iUVW that realizes the above flows, and controls the inverter 17 based on this PWM signal.

[0040] The frequency control unit 24 controls the d-axis current i ｄ When the electric power train 11 is heated by passing the current, the switching frequency f ＳＷ In this embodiment, the frequency control unit 24 sets or changes the switching frequency f ＳＷ In principle, the fundamental frequency f ｉｎｉ Set to.

[0041] However, the frequency control unit 24 does not ＳＷ Based on this, the switching frequency f ＳＷ is the fundamental frequency f ｉｎｉ to high frequency f Ｈ That is, the temperature T ＳＷ is low, and the switching frequency f ＳＷ Even if the temperature T of the switching element UP-WN is increased, ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ When it is difficult to reach the switching frequency f ＳＷ at high frequency f Ｈ Change to.

[0042] Also, warm-up position θ ｎ Even if the temperature T of the switching element UP-WN is repeatedly changed, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ If it is expected that the switching frequency f ＳＷ at low frequency f Ｌ may be changed to.

[0043] The flow rate adjusting unit 26 adjusts the d-axis current i ｄ When the electric powertrain 11 is heated by flowing the cooling water, the flow rate of the cooling water circulating between the battery 10 and the electric powertrain 11, which is a heat source, is adjusted.Ｗ When the cooling water temperature T Ｗ When the temperature drops, the flow rate adjusting unit 26 reduces the output of the cooling water circulation pump so that the flow rate of the cooling water decreases accordingly.

[0044] 3 is a flowchart relating to the warm-up control. As shown in FIG. 3, in step S10, the warm-up necessity determining unit 21 determines whether or not the battery 10 needs to be warmed up. In step S10, the battery temperature T ｂａｔ is the lower limit T ｂａｔ－ｌｉｍ When it is equal to or greater than (T ｂａｔ ≧T ｂａｔ－ｌｉｍ ), the warm-up necessity determining unit 21 determines that the temperature is not low enough to require warm-up. Therefore, the warm-up of the battery 10 is not performed. On the other hand, in step S10, the battery temperature T ｂａｔ is the lower limit T ｂａｔ－ｌｉｍ When it is lower than (T ｂａｔ <T ｂａｔ－ｌｉｍ ), the warm-up necessity determining unit 21 determines that the battery 10 is in a low temperature state and that warm-up is necessary. Therefore, the control proceeds to step S11.

[0045] In step S11, the rotation position control unit 22 determines the stop position θ of the rotating electric machine 16. ｓｔｏｐ The warm-up position θ closest to ｎ Then, in step S12, the rotational position control unit 22 rotates the rotary electric machine 16 until the rotational position θ of the rotary electric machine 16 reaches the initial position.

[0046] Thereafter, in step S13, the flow rate adjusting unit 26 adjusts the flow rate of the coolant. That is, when the warm-up of the battery 10 is started, the flow rate adjusting unit 26 starts circulating the coolant in step S13. When the warm-up of the battery 10 has already started, the flow rate adjusting unit 26 adjusts the flow rate of the coolant in step S13. Ｗ The flow rate of the cooling water is increased or decreased depending on the temperature.

[0047] In step S14, the frequency control unit 24 sets the switching frequency f ＳＷIn step S15, the current control unit 23 sets or changes the d-axis current i ｄ Set or change the size of

[0048] Then, in step S16, the current control unit 23 supplies the d-axis current i ｄ As a result, the electric power train 11 flows a d-axis current i ｄ The heat generated in the electric powertrain 11 is transported to the battery 10 by the cooling water. ｂａｔ rises.

[0049] Thereafter, in step S17, the warm-up necessity determining unit 21 determines whether the warm-up of the battery 10 has been completed. ｂａｔ is the lower limit T ｂａｔ－ｌｉｍ If it becomes more than (T ｂａｔ ≧T ｂａｔ－ｌｉｍ ), the warm-up necessity determining unit 21 determines that the warm-up of the battery 10 has been completed and that further warm-up is not required. Therefore, the warm-up control is terminated. On the other hand, in step S17, the battery temperature T ｂａｔ is still the lower limit T ｂａｔ－ｌｉｍ If it is lower than (T ｂａｔ <T ｂａｔ－ｌｉｍ ), the warm-up necessity determining unit 21 determines that it is still necessary to continue warming up the battery 10. Therefore, the control proceeds to step S18.

[0050] In step S18, the rotational position control unit 22 determines the warm-up position θ ｎ That is, the rotational position control unit 22 changes the warm-up position θ ｎ The rotating electric machine 16 is rotated until

[0051] In this embodiment, the rotational position control unit 22 is set to the warm-up position θ ｎ When the rotating electric machine 16 is rotated to change the d-axis current i ｄ However, the current control unit 23 temporarily stops the d-axis current i ｄIn this case, the amount of heat generated in the electric powertrain 11 can be maintained at Q ＰＴ Although the temperature is temporarily reduced, the heat generated by the electric powertrain 11 is maintained and the temperature is maintained at the warm-up position θ ｎ Therefore, the warm-up position θ ｎ Even if the temperature is changed, the battery 10 can be warmed up quickly.

[0052] As mentioned above, the warm-up position θ ｎ When the flow rate of the cooling water is changed, the control returns to step S13. ＳＷ (Step S14), the d-axis current i ｄ After setting the magnitude of the d-axis current i (step S15), the d-axis current i ｄ That is, the warm-up position θ ｎ Change of the new warm-up position θ ｎ d-axis current i ｄ The energization is repeated until the warm-up of the battery 10 is completed.

[0053] FIG. 4 shows the d-axis current i ｄ Phase current i for flowing ＵＶＷ and warm-up position θ ｎ As shown in FIG. ｑ is maintained at zero, and the d-axis current i ｄ Phase current i for flowing ＵＶＷ changes depending on the rotational position θ of the rotating electrical machine 16.

[0054] In addition, the phase current i ＵＶＷ When either of these becomes maximum, the phase current i ＵＶＷ The total amount (|i Ｕ |+|i Ｖ |+|i Ｗ Therefore, the d-axis current i ｄ The heat generation amount Q of the electric powertrain 11 generated by the flow of ＰＴ Specifically, θ = 30, 90, 150, 210, 270, 330 [deg] = θ １ , θ ２ , θ ３ , θ４ , θ ５ , θ ６ When this is the case, the d-axis current i ｄ Phase current i for flowing ＵＶＷ Therefore, the total amount of the rotational position θ of the rotating electrical machine 16 is maximized. １ -θ ６ ) when the d-axis current i ｄ The heat generation amount Q of the electric powertrain 11 generated by ＰＴ Therefore, the warm-up position θ to be used when warming up the battery 10 is maximized. ｎ is the above θ １ -θ ６ is.

[0055] Warm-up position θ ｎ = θ １ When using a V-phase upper arm switching element VP, a V-phase current i Ｖ flows, and the W-phase current i flows through the switching elements WN and UN constituting the lower arms of the W-phase and U-phase, respectively. Ｗ and U-phase current i Ｕ Then, the V-phase current i Ｖ The size of |i Ｖ | is the W-phase current i Ｗ and U-phase current i Ｕ The size of |i Ｗ |, |i Ｕ More specifically, |i Ｖ |=|i Ｗ |+|i Ｕ Further, a phase current i is supplied to the switching element VN constituting the lower arm of the V phase, the switching element WP constituting the upper arm of the W phase, and the switching element UP constituting the upper arm of the U phase. ＵＶＷ Therefore, the amount of heat generated by each of the switching elements UP to WN is different. ｎ = θ １ When the warm-up position θ is used, the switching element VP generates the most heat, followed by the switching elements WN and UN. ｎ = θ １ If the switching element VP continues to be used, it will reach its heat resistance temperature T ＳＷ－ｌｉｍ may be reached.

[0056] This is because, as will be explained below, the other warm-up positions θ ｎ = θ ２ -θ ６ The same applies when using

[0057] Warm-up position θ ｎ = θ ２ When using the U-phase current i Ｕ flows, and the V-phase current i flows through the switching elements VP and WP. Ｖ and W-phase current i Ｗ And the magnitude of these is |i Ｕ |=|i Ｖ |+|i Ｗ In addition, the switching elements UP, VN, and WN have a phase current i ＵＶＷ Therefore, the warm-up position θ ｎ = θ ２ If the temperature continues to rise, the switching element UN will reach its heat resistance temperature T ＳＷ－ｌｉｍ may be reached.

[0058] Warm-up position θ ｎ = θ ３ When using the switching element WP, the W-phase current i Ｗ flows, and the U-phase current i flows through the switching elements UN and VN. Ｕ and V-phase current i Ｖ And the magnitude of these is |i Ｗ |=|i Ｕ |+|i Ｖ In addition, the switching elements UP, VP, and WN have a phase current i ＵＶＷ Therefore, the warm-up position θ ｎ = θ ３ If the switching element WP continues to be used, it will reach the heat resistance temperature T ＳＷ－ｌｉｍ may be reached.

[0059] Warm-up position θ ｎ = θ ４ When using the V-phase current i Ｖ flows, and W-phase current i flows through the switching elements WP and UP, respectively. Ｗ and U-phase current i ＵAnd the magnitude of these is |i Ｖ |=|i Ｗ |+|i Ｕ In addition, the switching elements UN, VP, and WN have a phase current i ＵＶＷ Therefore, the warm-up position θ ｎ = θ ４ If the switching element VN continues to be used, it will reach its heat resistance temperature T ＳＷ－ｌｉｍ may be reached.

[0060] In addition, the warm-up position θ ｎ = θ １ and warm-up position θ ｎ = θ ４ Then, the phase current i ＵＶＷ That is, at the warm-up position θ ｎ = θ １ Then, the positive V-phase current i Ｖ , negative W-phase current i Ｗ , negative U-phase current i Ｕ flows, while the warm-up position θ ｎ = θ ４ Then, the negative V-phase current i Ｖ , positive W-phase current i Ｗ , positive U-phase current i Ｕ However, the magnitude of the V-phase current iV is |i Ｖ |, W phase current i Ｗ The size of |i Ｗ |, and U-phase current i Ｕ The size of |i Ｕ | is the warm-up position θ ｎ = θ １ and warm-up position θ ｎ = θ ４ In the following, the phase current i ＵＶＷ Warm-up position θ where ｎ is called the reversal position. Here, the warm-up position θ ｎ = θ １ and warm-up position θ ｎ = θ ４ are in a mutually inverted position relationship.

[0061] Warm-up position θ ｎ = θ ５ When using the U-phase current i Ｕflows, and the V-phase current i flows through the switching elements VN and WN. Ｖ and W-phase current i Ｗ And the magnitude of these is |i Ｕ |=|i Ｖ |+|i Ｗ In addition, the switching elements UN, VP, and WP have a phase current i ＵＶＷ Therefore, the warm-up position θ ｎ = θ ５ If you continue to use it, the switching element will reach its heat resistance temperature T ＳＷ－ｌｉｍ In addition, the warm-up position θ ｎ = θ ２ and warm-up position θ ｎ = θ ５ are in a mutually inverted position relationship.

[0062] Warm-up position θ ｎ = θ ６ When using the switching element WN, the W-phase current i Ｗ flows, and the U-phase current i flows through the switching elements UP and VP. Ｕ and V-phase current i Ｖ And the magnitude of these is |i Ｗ |=|i Ｕ |+|i Ｖ In addition, the switching elements UN, VN, and WP have a phase current i ＵＶＷ Therefore, the warm-up position θ ｎ = θ ６ If the switching element WN continues to be used, it will reach its heat resistance temperature T ＳＷ－ｌｉｍ In addition, the warm-up position θ ｎ = θ ３ and warm-up position θ ｎ = θ ６ are in a mutually inverted position relationship.

[0063] As described above, in the present embodiment, the stop position θ of the rotary electric machine 16 is ｓｔｏｐ The warm-up position θ closest to ｎ is selected as the initial position. In FIG. ｓｔｏｐ is the warm-up position θ ｎ = θ １ and warm-up position θ ｎ= θ ２ It is located between the warm-up position θ ｎ = θ ２ Therefore, the initial position is close to the warm-up position θ ｎ = θ ２ Stop position θ ｓｔｏｐ There are two warm-up positions θ ｎ If the position is exactly halfway between the two positions, the initial position is selected according to a predetermined setting (specification).

[0064] However, the rotation position control unit 22 determines the stop position θ ｓｔｏｐ And this stop position θ ｓｔｏｐ The initial position can be selected according to the direction of rotation of the rotating electric machine 16 immediately before it is stopped.

[0065] For example, when the rotating electric machine 16 rotates in the forward direction and reaches the stop position θ ｓｔｏｐ When the rotational position control unit 22 stops the rotational position θ ｎ can be selected as the initial position. Also, when the rotating electric machine 16 rotates in the negative direction and reaches the stop position θ ｓｔｏｐ When the rotating electric machine 16 is stopped in the positive direction, the rotational position control unit 22 can select the warm-up position θn closest to the negative direction as the initial position. ｓｔｏｐ When the engine is stopped at the warm-up position θ ｎ = θ ２ On the other hand, when the rotating electric machine 16 rotates in the negative direction and reaches the stop position θ ｓｔｏｐ When the engine is stopped at the warm-up position θ ｎ = θ １ is the initial position. In this way, the stop position θ ｓｔｏｐ and the stop position θ ｓｔｏｐ When the initial position is selected according to the rotation direction immediately before the electric powertrain 11 stopped, the rotating electric machine 16 can be rotated to the initial position while the gears included in the electric powertrain 11 are in mesh. This reduces the occurrence of noise due to gear backlash.

[0066] FIG. 5 shows the temperature T ＳＷ 1 is a graph showing a change in the temperature T of each switching element UP-WN over time from the start of the warm-up control. ＳＷ= {T ＵＰ , T ＵＮ , T ＶＰ , T ＶＮ , T ＷＰ , T ＷＮ}. Also, the warm-up position θ ｎ = θ ２ is the initial position, and the warm-up position θ ｎ are the inverted positions θ ２ and θ ５ can be switched alternately with

[0067] In addition, the warm-up position θ ｎ = θ ２ When the phase current i ＵＶＷ The temperature T of the switching elements UN, VP, and WP ＵＮ , T ＶＰ , T ＷＰ is shown by a solid line, and the warm-up position θ ｎ = θ ２ When the phase current i ＵＶＷ The temperature T of the switching elements UP, VN, and WN where no current flows ＵＰ , T ＶＮ , T ＷＮ The dashed line indicates the warm-up position θ ｎ The initial position (θ ２ ) and warm-up position θ ｎ = θ ２ In the d-axis current i ｄ The temperature T of the switching element UN in the comparative example in which the current is continuously applied is ＵＮ Also, the temperature T of each switching element UP-WN at the start of warm-up is ＳＷ are all equal, and the initial temperature T ＳＷ－ｉｎｉ is.

[0068] Also, here, each warm-up position θ ｎ = θ ２ , θ ５ The d-axis current i flows in ｄ is the basic d-axis current i ｄ－ｉｎｉ and the switching frequency fSW is the fundamental frequency f ｉｎｉ is.

[0069] As shown in FIG. 5, the warm-up position θ ｎ = θ ２When the warm-up of the battery 10 is started from the initial position, as shown by the solid line, the phase current i ＵＶＷ The temperature T of the switching elements UN, VP, and WP ＵＮ , T ＶＰ , T ＷＰ At this time, the maximum phase current (U-phase current i Ｕ ) flows through the switching element UN. ＵＮ On the other hand, as shown by the dashed line, the phase current i ＵＶＷ The temperature T of the switching elements UP, VN, and WN where no current flows ＵＰ , T ＮＶ , T ＷＮ will go down.

[0070] Warm-up position θ ｎ is θ ５ When the phase current i ＵＶＷ The temperature T of the switching elements UP, VN, and WN ＵＰ , T ＮＶ , T ＷＮ At this time, the maximum phase current (U-phase current i Ｕ ) flows through the switching element UP. ＵＰ On the other hand, the phase current i ＵＶＷ The temperature T of the switching elements UN, VP, and WP where no current flows ＵＮ , T ＶＰ , T ＷＰ will go down.

[0071] Then, the warm-up position θn is again θ ２ When the switching is switched to , the temperature T ＵＮ , T ＶＰ , T ＷＰ rises, and the temperature T of the switching elements UP, VN, and WN ＵＰ , T ＮＶ , T ＷＮ will go down.

[0072] In this way, the warm-up position θ ｎ When the switching is repeated, the temperature T ＳＷ The maximum phase current (U-phase current i Ｕ ) flows through the switching elements UP and UN. ＵＰ , TＵＮ Even if both of these temperatures T ＵＰ , T ＵＮ is the heat-resistant temperature T ＳＷ－ｌｉｍ The time to reach is delayed.

[0073] For example, the warm-up position θ ｎ Without changing the initial position, the warm-up position θ ｎ = θ ２ In the d-axis current i ｄ If the current continues to flow, the temperature T of the switching element UN, which is most likely to rise, will increase as shown by the dashed line. ＵＮ is the time t ａ Heat resistant temperature T ＳＷ－ｌｉｍ to reach.

[0074] Therefore, the predetermined heat generation amount Q ＰＴ The time required for the warm-up of the battery 10 to be completed (hereinafter referred to as the expected warm-up completion time t ｒｅｑ Before the temperature T ＵＮ is the heat-resistant temperature T ＳＷ－ｌｉｍ If the temperature of the switching element UN reaches ＵＮ Therefore, the actual completion of warm-up is delayed by the estimated warm-up completion time t ｒｅｑ That is, t ａ <t ｒｅｑ When the temperature is high, the heat resistance temperature T ＳＷ－ｌｉｍ The heat generation amount Q of the electric powertrain 11 is calculated by ＰＴ is limited, and the warm-up completion time t ｒｅｑ takes more time than

[0075] On the other hand, in this embodiment, the warm-up position θ ｎ When the temperature T of the switching elements UP and UN, which are most likely to rise, is repeatedly changed, as described above, ＵＰ , T ＵＮ is the heat-resistant temperature T ＳＷ－ｌｉｍ (hereinafter referred to as the time to reach the heat-resistant temperature t) ｂ ) is the temperature T ＵＮ is the heat-resistant temperature TＳＷ－ｌｉｍ The time t to reach ａ That is, t ａ <t ｂ In most cases, the time t ｂ is the estimated warm-up completion time t ｒｅｑ That is, in most cases, the warm-up position θ ｎ By repeatedly changing t ａ <t ｒｅｑ <t ｂ The switching element UP-WN reaches the heat resistance temperature T ＳＷ－ｌｉｍ The time it takes to reach

[0076] Therefore, the initial position (θ ２ ) and d-axis current i ｄ If the flow continues, the completion of warm-up will be delayed. ｎ If you repeatedly change the warm-up completion time t ｒｅｑ During this time, the heat generation amount Q of the electric powertrain 11 ＰＴ As a result, the warm-up is completed as scheduled at the estimated warm-up completion time t ｒｅｑ In other words, in this embodiment, the heat generation amount Q per unit time in the electric powertrain 11 is ＰＴ becomes larger, and the warm-up of the battery 10 can be completed more quickly than in the comparative example.

[0077] FIG. 6 shows the warm-up position θ ｎ 6 is a graph showing the transition of torque T when the warm-up position θ ｎ The rotational position control unit 22 limits the magnitude of the torque T generated by the rotary electric machine 16 when switching the warm-up position θ to a magnitude that does not cause the electric vehicle 100 to start moving. ｎ When the warm-up position θ is changed, the torque T generated by the rotary electric machine 16 is limited to a value that does not violate the parking lock. ｎ When switching the target torque T ＊ is the torque T equivalent to the parking lock ｒｏｃｋ Set to a value smaller than (T＊ <T ｒｏｃｋ ). This allows the warm-up position θ ｎ Even if the target torque T is changed, the torque T generated by the rotary electric machine 16 is suppressed, and the electric vehicle 100 does not start moving. ＊ is a torque T equivalent to the parking lock based on experiments or simulations. ｒｏｃｋ It is determined in advance depending on the

[0078] More specifically, the rotational position control unit 22 controls the warm-up position θ ｎ When changing the torque T of the rotating electrical machine 16 to the target torque T ＊ Then, the rotational position control unit 22 determines whether the torque T is equal to the target torque T ＊ After reaching the target torque T ＊ After that, the rotational position control unit 22 reduces the torque T to the target torque T ＊ Increase again to

[0079] Here, time t ０ Warm-up position θ ｎ The torque T of the rotating electrical machine 16 is changed to the target torque T ＊ And, at time t １ The torque T is the target torque T ＊ Furthermore, after time t1, the torque T increases again, and ２ Then, the target torque T ＊ Then, the target torque T ＊ is following suit.

[0080] In this way, the warm-up position θ ｎ When the torque T is changed as described above, the torsional vibration of the drive shaft included in the electric powertrain 11 is suppressed. ｎ Even if the rotational speed is changed, vibrations are unlikely to occur in the electric vehicle 100.

[0081] In FIG. 6, the warm-up position θ ｎ However, the present invention is not limited to this. ｓｔｏｐ The same applies to the case where the rotation position θ is adjusted from the stop position θ to the initial position.ｓｔｏｐ When adjusting the rotational position θ from the stop position θ to the initial position, the rotational position control unit 22 limits the torque T of the rotating electrical machine 16 as described above. ｓｔｏｐ When adjusting the torque T from the initial position to the target torque T ＊ Transition towards.

[0082] FIG. 7 shows the warm-up position θ ｎ 7 is a flowchart relating to the limiting of the torque rate when changing the torque rate. As shown in Fig. 7, in step S21, the rotational position control unit 22 determines whether the gears of the electric powertrain 11 are engaged. If it is determined in step S21 that the gears are not engaged, the process proceeds to step S22, where the rotational position control unit 22 limits the torque rate to a first torque rate threshold Th Ｒ１ The rotating electrical machine 16 starts to rotate with the torque rate limited to or below the first torque rate threshold Th Ｒ１ The torque rate is limited by the torque limiting value θ 1 , which continues from the start of rotation of the rotary electric machine 16 until the gears are engaged. ｎ When changing gear ratio, noise caused by gear backlash is less likely to occur.

[0083] If it is determined in step S21 that the gears are engaged, the process proceeds to step S23. In step S23, the rotational position control unit 22 calculates the torque rate based on a second torque rate threshold Th Ｒ２ The rotating electrical machine 16 is rotated while being limited to the second torque rate threshold Th Ｒ２ The torque rate is limited by the rotational position θ when the rotational position θ reaches the target warm-up position θ ｎ This continues until the warm-up position θ ｎ When changing the speed, torsional vibration of the drive shaft is less likely to occur.

[0084] The first torque rate threshold Th Ｒ１ and the second torque rate threshold Th Ｒ２is determined in advance by adaptation based on experiments, simulations, etc. Ｒ１ is determined by adaptation so as to suppress noise due to gear backlash. Ｒ２ is determined by adaptation so as to suppress torsional vibration of the drive shaft. Ｒ１ is usually the second torque rate threshold Th Ｒ２ That is, Th Ｒ１ <Th Ｒ２ Therefore, when the torque rate is equal to or greater than the first torque rate threshold Th Ｒ１ When the torque is limited to the range below this, noise caused by gear backlash is unlikely to occur, and torsional vibration of the drive shaft is also unlikely to occur.

[0085] The rotational position control unit 22 can determine whether the gears of the electric powertrain 11 are engaged, for example, based on the torque T output by the rotating electric machine 16. Specifically, the rotational position control unit 22 determines that the gears of the electric powertrain 11 are not engaged after the rotating electric machine 16 starts to rotate until the torque T is output. Then, when the torque T is output, the rotational position control unit 22 determines that the gears of the electric powertrain 11 are engaged.

[0086] In addition, warm-up position θ ｎ When the change of the rotational direction starts, the rotational position control unit 22 can determine whether the gears of the electric powertrain 11 are engaged based on the history of the rotational direction of the rotating electric machine 16. For example, if the rotating electric machine 16, which has rotated in a predetermined direction and is stopped, is further rotated in the same direction to change the rotational direction of the electric powertrain 11 to the warm-up position θ ｎ When changing the warm-up position θ, the rotational position control unit 22 can determine that the gears of the electric powertrain 11 are already engaged. ｎ When the rotational position control unit 22 changes the gears of the electric powertrain 11, the rotational position control unit 22 can determine that the gears of the electric powertrain 11 are not engaged.

[0087] Here, the warm-up position θ ｎ Although the example in which the torque rate is limited when changing the stop position θ has been described, the present invention is not limited to this. ｓｔｏｐ When adjusting the rotational position θ from the initial position to the initial position, the rotational position control unit 22 also limits the torque rate in the same manner as described above.

[0088] FIG. 8 shows the warm-up position θ ｎ 8 is a flowchart showing the selection of a destination when changing the current warm-up position θ ｎ Check whether the current warm-up position θ is the initial position. ｎ is the initial position, the process proceeds to step S32, and the rotational position control unit 22 ｎ the phase current i ＵＶＷ On the other hand, the current warm-up position θ ｎ is not the initial position, the process proceeds to step S33, and the rotational position control unit 22 ｎ is changed to the initial position. ｎ is alternately changed between an initial position and its inverted position.

[0089] More specifically, if the initial position is θ １ or θ ４ When the warm-up position θ ｎ is θ １ and θ ４ The initial position is changed alternately by θ ２ or θ ５ When the warm-up position θ ｎ is θ ２ and θ ５ The initial position is changed alternately by θ ３ or θ ６ When the warm-up position θ ｎ is θ ３ and θ ６ are alternately changed.

[0090] In this way, the warm-up position θ ｎ When the initial position and its reverse position are alternately changed, the warm-up position θ ｎ Each time the phase current iＵＶＷ The switching element UP-WN through which the warm-up d-axis current i ｄ The heat generated by the switching element UP-WN is dispersed within the inverter 17, and the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ becomes more difficult to reach.

[0091] Also, warm-up position θ ｎ is alternately changed between the initial position and its inverted position, the phase current i ＵＶＷ When the reverse position is used, the phase current i flows through the switching element UP-WN. ＵＶＷ Similarly, when using the reverse position, the phase current i ＵＶＷ When the initial position is used, the phase current i ＵＶＷ As a result, the phase current i ＵＶＷ The switching element UP-WN, whose temperature has risen due to the flow of current, is at the warm-up position θ ｎ After changing the warm-up position θ, the engine tends to cool down quickly. ｎ When the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ becomes more difficult to reach.

[0092] For convenience of explanation, the initial position and the reverse position are alternately set to the warm-up position θ ｎ However, the specific warm-up position θ other than the initial position is changed. ｎ and the reverse position alternately at the warm-up position θ ｎ For example, if the initial position is θ １ In principle, if θ １ and θ ４ Warm-up position θ ｎ However, if the initial position is θ １ Even if θ ２ and θ ５ Alternately warm-up position θ ｎ or by changing θ ３ and θ ６ Alternately warm-up position θ ｎcan be changed. If the initial position is θ １ In other words, the rotational position control unit 22 determines the current warm-up position θ regardless of the initial position. ｎ and the current warm-up position θ ｎ For phase current i ＵＶＷ and the warm-up position θ ｎ In this case, as described above, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ becomes more difficult to reach.

[0093] FIG. 9 shows the warm-up position θ ｎ 9 is a flowchart showing the selection of a destination when changing the phase current i ＵＶＷ The warm-up position θ ｎ You can also select the destination of the change.

[0094] Specifically, in step S41, the rotational position control unit 22 determines the current warm-up position θ ｎ is the phase current i ＵＶＷ Of which, U-phase current i Ｕ The warm-up position θ at which ｎ Then, the current warm-up position θ ｎ is the U-phase current i Ｕ The warm-up position θ at which ｎ If so, the process proceeds to step S42, and the rotational position control unit 22 calculates the W-phase current i Ｗ or V-phase current i Ｖ The next warm-up position θ where ｎ , warm-up position θ ｎ On the other hand, the current warm-up position θ ｎ is the U-phase current i Ｕ The warm-up position θ at which ｎ If not, the process proceeds to step S43.

[0095] In step S43, the rotational position control unit 22 determines the current warm-up position θ ｎ is the phase current i ＵＶＷ Of which, V-phase current i Ｖ The warm-up position θ at which ｎThen, the current warm-up position θ ｎ is the V-phase current i Ｖ The warm-up position θ at which ｎ If so, the process proceeds to step S44, and the rotational position control unit 22 determines whether the U-phase current i Ｕ or W-phase current i Ｗ The next warm-up position θ where ｎ , warm-up position θ ｎ On the other hand, the current warm-up position θ ｎ is the V-phase current i Ｖ The warm-up position θ at which ｎ If not, the process proceeds to step S45.

[0096] In step S45, the rotational position control unit 22 determines the current warm-up position θ ｎ is the W-phase current i Ｗ The warm-up position θ at which ｎ and the V-phase current i Ｖ or U-phase current i Ｕ The next warm-up position θ where ｎ , warm-up position θ ｎ Change the

[0097] In this way, the warm-up position θ ｎ When changing the warm-up position θ ｎ is the total warm-up position θ ｎ Specifically, it changes cyclically via ...→θ １ →θ ２ →θ ３ →θ ４ →θ ５ →θ ６ →θ １ →… or…→θ １ →θ ６ →θ ５ →θ ４ →θ ３ →θ ２ →θ １ →... and so on, warm-up position θ ｎ is repeatedly changed. In this case, the d-axis current i ｄ Since the heat generated by the ＳＷ In particular, the heat resistance temperature T ＳＷ－ｌｉｍbecomes more difficult to reach.

[0098] FIG. 10 shows the switching frequency f ＳＷ 10, in step S51, the frequency control unit 24 adjusts the temperature T ＳＷ is obtained and used as the element temperature threshold value Th ＳＷ Here, the frequency control unit 24 compares the temperature T ＳＷ = {T ＵＰ , T ＵＮ , T ＶＰ , T ＶＮ , T ＷＰ , T ＷＮ} is the maximum value of the element temperature threshold Th ＳＷ Compare with.

[0099] Element temperature threshold Th ＳＷ is the temperature T of the switching element UP-WN during warm-up control. ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ This is the criterion for determining whether the switching element UP-WN is in a low temperature state sufficiently so as not to exceed the element temperature threshold Th. ＳＷ is determined in advance based on experiments, simulations, etc. However, the element temperature threshold Th ＳＷ is at least the heat-resistant temperature T ＳＷ－ｌｉｍ is set to a value lower than

[0100] In step S51, the temperature T ＳＷ is the element temperature threshold Th ＳＷ If it is determined that the switching element UP-WN is in a sufficiently low temperature state, the process proceeds to step S52. Then, in step S52, the frequency control unit 24 adjusts the switching frequency f ＳＷ is the fundamental frequency f ｉｎｉ High frequency f Ｈ Set or change to

[0101] On the other hand, in step S51, the temperature T ＳＷ is the element temperature threshold Th ＳＷIf the switching frequency f is higher than the switching frequency f , and the switching element UP-WN is not in a sufficiently low temperature state, the process proceeds to step S53. ＳＷ is the fundamental frequency f ｉｎｉ Set or change to

[0102] The temperature T of the switching element UP-WN ＳＷ Switching frequency f based on ＳＷ The adjustment of the switching frequency f is performed every time step S14 (see FIG. 3) is executed. Therefore, for example, when the warm-up control is started, if the switching element UP-WN is in a sufficiently low temperature state, the switching frequency f ＳＷ is the high frequency f Ｈ Furthermore, even after the start of the warm-up control, if the switching elements UP-WN are cooled by the circulation of cooling water and reach a sufficiently low temperature, the switching frequency f ＳＷ is the high frequency f Ｈ is set to

[0103] In this way, the temperature T of the switching element UP-WN ＳＷ Based on this, the switching frequency f ＳＷ When the switching frequency f is adjusted, the amount of heat generated in the inverter 17 increases. ＳＷ is the high frequency f Ｈ When the switching frequency f is set to , the heat generated in each of the switching elements UP-WN increases due to so-called switching loss. ＳＷ Always use the fundamental frequency f ｉｎｉ The heat generation amount Q of the electric powertrain 11 is ＰＴ Therefore, the warm-up of the battery 10 can be completed particularly quickly. Specifically, the warm-up of the battery 10 can be completed, for example, within a warm-up completion estimated time t ｒｅｑ may be completed earlier than

[0104] In other words, the warm-up position θ ｎ The switching element UP-WN is changed to the heat-resistant temperature T ＳＷ－ｌｉｍ At least temporarily, the switching frequency f ＳＷ is the fundamental frequency fｉｎｉ The heat generation amount Q of the electric powertrain 11 is set higher than ＰＴ As a result, the warm-up of the battery 10 is completed earlier.

[0105] FIG. 11 shows the switching frequency f ＳＷ 11 is a flowchart relating to the initial setting of the warm-up position θ ｎ Even if the temperature T of the switching element UP-WN is repeatedly changed, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ Here, the frequency control unit 24 determines whether the estimated warm-up completion time t ｒｅｑ and the time t ｂ This determination is made by comparing the estimated warm-up completion time t ｒｅｑ For example, the d-axis current i ｄ is the basic d-axis current i ｄ－ｉｎｉ and the switching frequency f ＳＷ is the fundamental frequency f ｉｎｉ The heat generation amount Q of the electric powertrain 11 when ＰＴ and battery temperature T ｂａｔ The time to reach the heat-resistant temperature t ｂ is the warm-up position θ ｎ Specific modifications and d-axis current i ｄ It can be calculated based on the magnitude of

[0106] In step S61, the estimated warm-up completion time t ｒｅｑ The time to reach the heat-resistant temperature t ｂ is short (t ｂ <t ｒｅｑ ), warm-up position θ ｎ Even if the temperature T of the switching element UP-WN is repeatedly changed, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ If it is expected that the switching frequency f will exceed the predetermined value, the process proceeds to step S62. ＳＷ is the fundamental frequency f ｉｎｉ Low frequency f ＬSet to.

[0107] On the other hand, in step S61, the heat-resistant temperature reaching time t ｂ is the estimated warm-up completion time t ｒｅｑ or more (t ｂ ≧t ｒｅｑ ), warm-up position θ ｎ By repeatedly changing the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ If it is not expected that the switching frequency f will exceed 100 Hz, the process proceeds to step S63. In step S63, the frequency control unit 24 ＳＷ is the fundamental frequency f ｉｎｉ Set to.

[0108] In this way, when starting the warm-up, the frequency control unit 24 basically sets the switching frequency f ＳＷ is the fundamental frequency f ｉｎｉ However, during warm-up, the warm-up position θ ｎ Even if the temperature T of the switching element UP-WN is repeatedly changed, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ When it is expected that the switching frequency f ＳＷ is the fundamental frequency f ｉｎｉ As a result, the frequency control unit 24 reduces the amount of heat generated by the switching element UP-WN. As a result, the temperature T ＳＷ is the heat resistance temperature T ＳＷ－ｌｉｍ becomes more difficult to reach.

[0109] FIG. 12 shows the d-axis current i ｄ 12, in step S71, the current control unit 23 adjusts the temperature T ＳＷ is obtained and used as the element temperature threshold value Th ＳＷ Here, the current control unit 23 compares the temperature T ＳＷ = {T ＵＰ , T ＵＮ , T ＶＰ , T ＶＮ , T ＷＰ, T ＷＮ} is the maximum value of the element temperature threshold Th ＳＷ Compare with.

[0110] In step S71, the temperature T of the switching element UP-WN ＳＷ is the element temperature threshold Th ＳＷ If it is determined that the temperature of the switching element UP-WN is sufficiently low, the process proceeds to step S72. ＭＧ is acquired and used as the rotating electrical machine temperature threshold value Th ＭＧ Compare with.

[0111] Rotating electrical machine temperature threshold Th ＭＧ is the temperature T of the rotating electrical machine 16 during the warm-up control. ＭＧ is the heat-resistant temperature T ＭＧ－ｌｉｍ This is a criterion for determining whether the rotating electrical machine 16 is in a sufficiently low temperature state so as not to exceed the rotating electrical machine temperature threshold value Th ＭＧ is determined in advance based on experiments, simulations, etc. However, the rotating electrical machine temperature threshold value Th ＭＧ is at least the heat-resistant temperature T ＭＧ－ｌｉｍ is set to a value lower than

[0112] In step S72, the temperature T ＭＧ is the rotating electrical machine temperature threshold value Th ＭＧ If it is determined that the temperature of the rotating electrical machine 16 is sufficiently low, the process proceeds to step S73. Then, in step S73, the current control unit 23 calculates the d-axis current i ｄ The fundamental d-axis current i ｄ－ｉｎｉ High d-axis current i ｄＨ Set or change to

[0113] On the other hand, in step S71, the temperature T ＳＷ is the element temperature threshold Th ＳＷ When the temperature T ＭＧ is the rotating electrical machine temperature threshold value Th ＭＧIf the temperature is higher than the d-axis current i ｄ The basic d-axis current i ｄ－ｉｎｉ Set or change to

[0114] The temperature T of the switching element UP-WN ＳＷ and the temperature T of the rotating electrical machine 16 ＭＧ d-axis current i based on ｄ The adjustment of the d-axis current i is performed every time step S15 (see FIG. 3) is executed. Therefore, for example, when the warm-up control is started, if the switching element UP-WN and the rotating electrical machine 16 are in a sufficiently low temperature state, the d-axis current i ｄ is the high d-axis current i ｄＨ Furthermore, even after the start of the warm-up control, if the switching element UP-WN and the rotating electrical machine 16 are cooled by the circulation of the cooling water and both of them reach a sufficiently low temperature, the d-axis current i ｄ is the high d-axis current i ｄＨ is increased to

[0115] In this way, the temperature T of the switching element UP-WN ＳＷ and the temperature T of the rotating electrical machine 16 ＭＧ Based on this, the d-axis current i ｄ When the d-axis current i is adjusted, the heat generation amount of the inverter 17 and the heat generation amount of the rotating electrical machine 16 increase. ｄ The basic d-axis current i ｄ－ｉｎｉ The heat generation amount Q of the electric powertrain 11 is ＰＴ Therefore, the warm-up of the battery 10 can be completed particularly quickly. Specifically, the warm-up of the battery 10 can be completed, for example, at a warm-up completion estimated time t ｒｅｑ may be completed earlier than

[0116] In other words, the warm-up position θ ｎ The switching element UP-WN is changed to the heat-resistant temperature T ＳＷ－ｌｉｍ At least temporarily, the d-axis current i ｄ By increasing the heat generation amount Q of the electric powertrain 11, ＰＴAs a result, the warm-up of the battery 10 is completed earlier.

[0117] FIG. 13 shows the d-axis current i ｄ 13 is a flowchart relating to the initial setting of the warm-up position θ ｎ Even if the temperature T of the switching element UP-WN is repeatedly changed, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ Here, the current control unit 23 determines whether the estimated warm-up completion time t ｒｅｑ and the time t ｂ This determination is made by comparing:

[0118] In step S81, the estimated warm-up completion time t ｒｅｑ The time to reach the heat-resistant temperature t ｂ is short (t ｂ <t ｒｅｑ ), warm-up position θ ｎ Even if the temperature T of the switching element UP-WN is repeatedly changed, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ If it is expected that the d-axis current i ｄ The basic d-axis current i ｄ－ｉｎｉ The low d-axis current i ｄＬ Set to.

[0119] On the other hand, in step S81, the heat-resistant temperature reaching time t ｂ is the estimated warm-up completion time t ｒｅｑ or more (t ｂ ≧t ｒｅｑ ), warm-up position θ ｎ By repeatedly changing the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ If it is not expected that the d-axis current i ｄ The basic d-axis current i ｄ－ｉｎｉ Set to.

[0120] In this way, when starting the warm-up, the current control unit 23 basically controls the d-axis current i ｄ The basic d-axis current i ｄ－ｉｎｉ However, during warm-up, the warm-up position θ ｎ Even if the temperature T of the switching element UP-WN is repeatedly changed, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ When the d-axis current i ｄ The magnitude of the basic d-axis current i ｄ－ｉｎｉ As a result, the current control unit 23 reduces the amount of heat generated by the switching element UP-WN. As a result, the temperature T ＳＷ is the heat resistance temperature T ＳＷ－ｌｉｍ becomes more difficult to reach.

[0121] As described above, in the warm-up control method according to the above embodiment, in the electric vehicle 100 having the electric power train 11 including the inverter 17 and the rotating electric machine 16, when the rotation of the rotating electric machine 16 is stopped, the d-axis current i ｄ flows, and the d-axis current i ｄ This is a warm-up control method for warming up a predetermined target device (for example, the battery 10) mounted on the electric vehicle 100 by using heat generated in the electric power train 11 by flowing the d-axis current i ｄ Phase current i for flowing ＵＶＷ The total amount (|i Ｕ |+|i Ｖ |+|i Ｗ |) are maximized at multiple warm-up positions θ ｎ One warm-up position θ ｎ Select the warm-up position θ ｎ The rotating electric machine 16 is rotated to the selected warm-up position θ ｎ In the d-axis current i ｄ Then, while the target device (battery 10) is warming up, the d-axis current i ｄ Warm-up position θ ｎ Repeatedly change.

[0122] In this way, during the warm-up control, the warm-up position θ ｎWhen the value is repeatedly changed, the heat generation amount Q of the electric powertrain 11 ＰＴ While maintaining the temperature T of the switching element UP-WN ＳＷ is the heat resistance temperature T ＳＷ－ｌｉｍ Therefore, it becomes difficult to reach the warm-up position θ ｎ By repeatedly changing the d-axis current i at the initial position, the warm-up can be completed quickly. ｄ If the flow continues, the completion of warm-up will be delayed. ｎ By repeatedly changing the value, the warm-up is completed as scheduled within the expected warm-up completion time t ｒｅｑ Completed in.

[0123] In the warm-up control method according to the above embodiment, a threshold value (Th Ｒ１ , Th Ｒ２ ) and warm-up position θ ｎ When changing the torque rate, the threshold value (Th Ｒ１ , Th Ｒ２ ) The rotating electrical machine 16 is rotated so that the following occurs:

[0124] In this way, when the torque rate is limited, the warm-up position θ ｎ Even if the rotational speed is changed, the electric vehicle 100 is unlikely to generate noise or vibration.

[0125] In the warm-up control method according to the above embodiment, the first torque rate threshold Th used when starting to rotate the rotary electric machine 16 is used as a threshold for the torque rate. Ｒ１ is set, and the torque rate is set to a first torque rate threshold Th Ｒ１ Restrict to the following:

[0126] In this way, the warm-up position θ ｎ When changing the torque rate, the torque rate is set to the first torque rate threshold Th Ｒ１ If limited to, the warm-up position θ ｎ Even if the rotating electrical machine 16 is rotated to change the rotational speed, noise due to gear backlash is unlikely to occur.

[0127] In the warm-up control method according to the above embodiment, a second torque rate threshold Th is determined according to the torsional vibration characteristics of the drive shaft as a threshold for the torque rate. Ｒ２ Set the warm-up position θ ｎ When the rotating electrical machine 16 is rotated to change the torque rate, the torque rate is set to at least the second torque rate threshold value Th Ｒ２ Restrict to the following:

[0128] In this way, the warm-up position θ ｎ When changing the torque rate, the torque rate is set to the second torque rate threshold Th Ｒ２ If limited to the following, the warm-up position θ ｎ Even if the rotating electrical machine 16 is rotated to change the rotational speed, torsional vibration of the drive shaft is unlikely to occur.

[0129] In the warm-up control method according to the above embodiment, the warm-up position θ ｎ When changing the torque T of the rotating electrical machine 16, the predetermined target torque T ＊ and the target torque T ＊ After reaching the target torque T, the torque T of the rotating electric machine 16 is reduced, and then the torque T of the rotating electric machine 16 is set to the target torque T ＊ Increase again to

[0130] Warm-up position θ ｎ When changing the torque T as described above, the warm-up position θ ｎ Even if the rotating electrical machine 16 is rotated to change the rotational speed, torsional vibration of the drive shaft is unlikely to occur.

[0131] In the warm-up control method according to the above embodiment, the temperature T ＳＷ and the temperature T ＳＷ is a predetermined element temperature threshold Th ＳＷ If the switching frequency f of the inverter 17 is ＳＷ Increases.

[0132] In this way, when the switching element UP-WN is in a sufficiently low temperature state, the switching frequency f ＳＷ When the value of the heat generated by the electric powertrain 11 is increased, the heat generation amount Q ＰＴIn particular, the amount of heat generated in the switching elements UP-WN can be increased, resulting in faster completion of warm-up.

[0133] In the warm-up control method according to the above embodiment, the temperature T ＳＷ , and the temperature T of the rotating electrical machine 16 ＭＧ and the temperature T ＳＷ is a predetermined element temperature threshold Th ＳＷ and the temperature T ＭＧ is a predetermined rotating electrical machine temperature threshold value Th ＭＧ If the d-axis current i ｄ Increases.

[0134] In this way, when the switching element UP-WN and the rotating electrical machine 16 are in a sufficiently low temperature state, the d-axis current i ｄ When the value of the heat generated by the electric powertrain 11 is increased, the heat generation amount Q ＰＴ As a result, warm-up is completed sooner.

[0135] In the warm-up control method according to the above embodiment, the warm-up position θ ｎ Even if the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ When the switching frequency f of the inverter 17 exceeds ＳＷ , or d-axis current i ｄ Decreases.

[0136] In this way, the warm-up position θ ｎ Even if the temperature T of the switching element UP-WN is repeatedly changed, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ Even if the switching frequency f ＳＷ or d-axis current i ｄ If the temperature T ＳＷ The heat resistance temperature T ＳＷ－ｌｉｍ becomes more difficult to reach.

[0137] In the warm-up control method according to the above embodiment, the current warm-up position θ ｎand the current warm-up position θ ｎ For phase current i ＵＶＷ and the warm-up position θ ｎ Change the

[0138] In this way, the current warm-up position θ ｎ and the current warm-up position θ ｎ For phase current i ＵＶＷ and the warm-up position θ ｎ When changing the warm-up position θ ｎ Each time the phase current i ＵＶＷ The switching element UP-WN through which the warm-up d-axis current i ｄ The heat generated by the switching element UP-WN is dispersed within the inverter 17, and the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ In addition, it becomes difficult for the phase current i ＵＶＷ The switching element UP-WN, whose temperature has risen due to the flow of current, is at the warm-up position θ ｎ After changing the warm-up position θ, the engine tends to cool down quickly. ｎ When the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ becomes more difficult to reach.

[0139] In the warm-up control method according to the above embodiment, the phase current i ＵＶＷ The warm-up position θ ｎ Change the

[0140] In this way, the phase current i ＵＶＷ The warm-up position θ ｎ When changing the d-axis current for warm-up i ｄ Since the heat generated by the ＳＷ In particular, the heat resistance temperature T ＳＷ－ｌｉｍ It is difficult to reach.

[0141] In the warm-up control method according to the above embodiment, the warm-up position θ ｎ The warm-up position θ ｎand the d-axis current i ｄ flush.

[0142] In this way, the warm-up position θ ｎ The warm-up position θ ｎ and the d-axis current i ｄ and intermittently warm up at the warm-up position θ ｎ When the value is changed, the heat generation amount Q of the electric powertrain 11 ＰＴ Therefore, the temperature T ＳＷ is the heat-resistant temperature T ＳＷ－ｌｉｍ This makes it difficult to reach this temperature, while making it easier to complete warm-up early.

[0143] In the warm-up control method according to the above embodiment, the warm-up position θ ｎ The d-axis current i ｄ The time for which the warm-up position θ ｎ This can be shorter than the time required to change the

[0144] In this way, the warm-up position θ ｎ The d-axis current i ｄ The time for which the warm-up position θ ｎ The time required to change the warm-up position θ is set to be shorter than the time required to change the warm-up position θ ｎ When the temperature T of the switching element UP-WN is changed, ＳＷ In particular, the heat resistance temperature T ＳＷ－ｌｉｍ In addition, deterioration (reduced life span) of the switching elements UP-WN can be easily prevented.

[0145] In the warm-up control method according to the above embodiment, the warm-up position θ ｎ When changing the rotational speed, the rotating electric machine 16 is rotated in a certain direction.

[0146] In this way, the warm-up position θ ｎ When changing the warm-up position θn, if the rotating electric machine 16 is rotated in a certain direction, the warm-up position θn can be changed while the gears of the electric powertrain 11 are kept in mesh. ｎ Even if the gear ratio is changed, noise caused by gear backlash is unlikely to occur.

[0147] In the warm-up control method according to the above embodiment, the warm-up position θ ｎWhen changing the rotation direction, the rotating electric machine 16 can be rotated in the reverse direction relative to the previous rotation direction.

[0148] In this way, the warm-up position θ ｎ When the warm-up position θ is changed, if the rotating electric machine 16 is rotated in the reverse direction relative to the previous rotation direction, the sign (positive or negative) of the torque T of the rotating electric machine 16 is reversed, and the time average becomes zero. ｎ This is particularly useful when warming up the battery 10 or the like in a state where the movement of the electric vehicle 100 is not restricted by a parking lock or brake.

[0149] The warm-up control device according to the above embodiment is configured to supply a d-axis current i to the rotating electric machine 16 when the rotating electric machine 16 is stopped in an electric vehicle 100 having an electric power train 11 including an inverter 17 and a rotating electric machine 16. ｄ flows, and the d-axis current i ｄ The warm-up control device (controller 13) warms up a predetermined target device (for example, the battery 10) mounted on the electric vehicle 100 by using heat generated in the electric power train 11 by flowing the d-axis current i ｄ Phase current i for flowing ＵＶＷ The total amount (|i Ｕ |+|i Ｖ |+|i Ｗ |) are maximized at multiple warm-up positions θ ｎ One warm-up position θ ｎ Select the warm-up position θ ｎ a rotation position control unit 22 that rotates the rotating electrical machine 16 to the selected warm-up position θ ｎ In the d-axis current i ｄ The rotational position control unit 22 controls the d-axis current i ｄ Warm-up position θ ｎ Repeatedly change.

[0150] In this way, during the warm-up control, the warm-up position θ ｎ When the value is repeatedly changed, the heat generation amount Q of the electric powertrain 11 ＰＴWhile maintaining the temperature T of the switching element UP-WN ＳＷ is the heat resistance temperature T ＳＷ－ｌｉｍ Therefore, it becomes difficult to reach the warm-up position θ ｎ By repeatedly changing the d-axis current i at the initial position, the warm-up can be completed quickly. ｄ If the flow continues, the completion of warm-up will be delayed. ｎ By repeatedly changing the value, the warm-up is completed as scheduled within the expected warm-up completion time t ｒｅｑ Completed in.

[0151] The above describes embodiments and modifications of the present invention, but the configurations described in the above embodiments and modifications merely illustrate some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

Claims

1. A warm-up control method for an electric vehicle having an electric powertrain including an inverter and a rotating electric machine, in which a d-axis current is passed through the rotating electric machine when rotation of the rotating electric machine is stopped, and heat generated in the electric powertrain by passing the d-axis current is used to warm up a specified target device mounted on the electric vehicle, the warm-up control method comprising: selecting one warm-up position from a plurality of warm-up positions that maximizes the total amount of phase current for passing the d-axis current; rotating the rotating electric machine to the selected warm-up position; passing the d-axis current at the selected warm-up position; and repeatedly changing the warm-up position for passing the d-axis current while warming up the target device.

2. A warm-up control method according to claim 1, comprising: setting a threshold value for a torque rate, which is the rate of change of torque over time generated by the rotating electric machine; and when changing the warm-up position, rotating the rotating electric machine so that the torque rate is equal to or less than the threshold value.

3. A warm-up control method as described in claim 2, wherein a first torque rate threshold value used when starting to rotate the rotating electric machine is set as the threshold value for the torque rate, and the torque rate is limited to be equal to or less than the first torque rate threshold value from the time when the rotating electric machine starts to rotate until the gears of the electric powertrain mesh.

4. A warm-up control method as claimed in claim 2, wherein a second torque rate threshold determined according to the torsional vibration characteristics of the drive shaft is set as the threshold value for the torque rate, and when the rotating electric machine is rotated to change the warm-up position, the torque rate is limited to at least the second torque rate threshold or less.

5. A warm-up control method according to claim 1, wherein, when changing the warm-up position, the torque of the rotating electric machine is increased to a predetermined target torque, and after reaching the target torque, the torque of the rotating electric machine is reduced, and the torque of the rotating electric machine is increased again to the target torque.

6. A warm-up control method according to claim 1, comprising: acquiring the temperature of a switching element included in the inverter; and increasing the switching frequency of the inverter when the temperature of the switching element is equal to or lower than a predetermined element temperature threshold value.

7. A warm-up control method according to claim 1, comprising: acquiring the temperature of a switching element included in the inverter and the temperature of the rotating electric machine; and increasing the d-axis current when the temperature of the switching element is equal to or lower than a predetermined element temperature threshold and the temperature of the rotating electric machine is equal to or lower than a predetermined rotating electric machine temperature threshold.

8. A warm-up control method according to claim 1, wherein, when the temperature of a switching element included in the inverter exceeds a heat-resistant temperature before warm-up is completed even after the warm-up position is changed, the switching frequency of the inverter or the d-axis current is reduced.

9. A warm-up control method according to claim 1, wherein the warm-up position is changed alternately between the current warm-up position and an inversion position where the phase current is inverted relative to the current warm-up position.

10. A warm-up control method according to claim 1, wherein the warm-up position is changed so that the phase with the maximum phase current is switched over in sequence.

11. A warm-up control method according to claim 1, wherein the d-axis current is caused to flow while the warm-up position remains in place for a longer period than the time required to change the warm-up position.

12. A warm-up control method according to claim 1, wherein the time during which the warm-up position is maintained and the d-axis current flows is shorter than the time required to change the warm-up position.

13. A warm-up control method according to claim 1, wherein when the warm-up position is changed, the rotating electrical machine is rotated in a fixed direction.

14. A warm-up control method according to claim 1, wherein when the warm-up position is changed, the rotating electric machine is rotated in a direction reverse to the previous rotation direction.

15. A warm-up control device for an electric vehicle having an electric powertrain including an inverter and a rotating electric machine, which causes a d-axis current to flow through the rotating electric machine when rotation of the rotating electric machine is stopped, and warms up a specified target device mounted on the electric vehicle using heat generated in the electric powertrain by flowing the d-axis current, the warm-up control device comprising: a rotational position control unit that selects one warm-up position from a plurality of warm-up positions that maximizes the total amount of phase current for flowing the d-axis current, and rotates the rotating electric machine to the selected warm-up position; and a current control unit that flows the d-axis current at the selected warm-up position, wherein the rotational position control unit repeatedly changes the warm-up position for flowing the d-axis current while warming up the target device.

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