Electric vehicle control device

Abstract

To provide a control device of an electric vehicle which can suppress degradation of a battery.SOLUTION: In a control device 1 of an electric vehicle according to one aspect of the present disclosure, an ECU 17, in a case where a motor 13 performs regenerative power generation in such a situation that a user does not want to perform charging of a battery 14, performs regeneration prohibition control of preventing the battery 14 from being charged by preventing the flow in the battery 14 of a regenerative current Ib obtained when the regenerative power generation is performed by making an inverter 21 generate phase voltages Vu, Vv, Vw in the same magnitude as the induced voltage ωφ generated by the motor 13 with the regenerative power generation.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a control device for an electric vehicle. [Background technology]

[0002] As a conventional technology relating to a control device for an electric vehicle, Patent Document 1 discloses a technology for performing low-efficiency regenerative control that reduces the power obtained by regenerative power generation when the motor in a hybrid vehicle generates power regeneratively (using the rotational power transmitted from the tires) when the battery is close to being fully charged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-77808 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology disclosed in Patent Document 1, low-efficiency regeneration control is performed when the battery is nearly fully charged, but the battery is continuously charged, which may cause the battery to become overcharged, which may lead to battery deterioration.

[0005] Therefore, the present disclosure has been made to solve the above-mentioned problems, and has an object to provide a control device for an electric vehicle that can suppress deterioration of the battery. [Means for solving the problem]

[0006] One form of the present disclosure made to solve the above problems is a control device for an electric vehicle having a motor connected to a tire, regeneratively controlled and powered by an inverter, and performing regenerative power generation using rotational power transmitted from the tire, a battery connected to the inverter, and a control unit that controls the electric vehicle, wherein, when the motor performs regenerative power generation under a situation in which charging of the battery is not desired, the control unit performs charge prevention control to prevent the battery from being charged by causing the inverter to generate a voltage having the same magnitude as an induced voltage generated in the motor as a result of the regenerative power generation, thereby preventing the regenerative current obtained by the regenerative power generation from flowing to the battery.

[0007] According to this aspect, when charging the battery is not desired due to the risk of battery deterioration, even if the regenerative conditions are met and the motor performs regenerative power generation, the regenerative current does not flow to the battery, so charging of the battery can be prevented, thereby suppressing battery deterioration.

[0008] In the above aspect, it is preferable that the device has a charge amount value acquisition unit that acquires the value of the charge amount of the battery, and that a situation in which it is not desired to charge the battery is a situation in which the value of the charge amount of the battery acquired by the charge amount value acquisition unit is equal to or greater than a predetermined threshold value that is close to full charge.

[0009] According to this aspect, when the charge amount of the battery is equal to or greater than a predetermined threshold value close to full charge, even if the regenerative condition is met and the motor performs regenerative power generation, the regenerative current does not flow to the battery, so that the battery can be prevented from being charged. Therefore, the battery can be prevented from being overcharged, and thus the deterioration of the battery can be prevented.

[0010] In the above aspect, it is preferable that the control unit has a regenerative current value acquisition unit that acquires the value of the regenerative current, and when the charging prevention control is executed, the control unit performs regenerative current zero control, which performs feedback control so that the value of the regenerative current becomes zero by adjusting the voltage generated by the inverter based on the value of the regenerative current acquired by the regenerative current value acquisition unit.

[0011] According to this aspect, when the charging prevention control is executed, the battery can be more reliably prevented from being charged. Effect of the Invention

[0012] According to the control device for an electric vehicle of the present disclosure, deterioration of the battery can be suppressed. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a structural diagram of a control device for a hybrid vehicle according to the first and second embodiments. [Diagram 2] FIG. 2 is a configuration diagram of a motor, a battery, and an inverter. [Diagram 3] FIG. 2 is a diagram illustrating the configuration of a motor. [Figure 4] FIG. 4 is a flowchart showing the contents of control performed in the first embodiment. [Diagram 5] FIG. 11 is a diagram showing an example of waveforms when regenerative control is performed. [Figure 6] FIG. 13 is a diagram showing a motor model when regenerative control is performed. [Figure 7] FIG. 4 is a diagram showing a current flow when regenerative control is performed. [Figure 8] FIG. 11 is a diagram showing an example of waveforms when regeneration inhibition control is performed. [Figure 9] FIG. 4 is a control block diagram of regeneration inhibition control. [Figure 10] FIG. 13 is a diagram showing a motor model when regeneration prohibition control is performed. [Figure 11] FIG. 4 is a diagram showing a current flow when regeneration inhibition control is performed. [Figure 12]FIG. 11 is a flowchart showing the contents of control performed in the second embodiment. [Figure 13] FIG. 11 is a diagram showing an example of waveforms when battery current 0A control is performed. [Figure 14] FIG. 1 is a control block diagram of a battery current 0 A control. [Figure 15] FIG. 11 is a diagram showing an example of waveforms when battery current 0 A control is not performed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, a hybrid vehicle control device 1 will be described as an example of an embodiment of the control device for an electric vehicle of the present disclosure. Note that in the following description, a hybrid vehicle is exemplified as the electric vehicle, but the control device for an electric vehicle of the present disclosure can also be applied to electric vehicles other than hybrid vehicles (for example, electric automobiles, etc.).

[0015] [First embodiment] First, the first embodiment will be described.

[0016] <Hybrid vehicle overview> First, an overview of a hybrid vehicle 10 in a hybrid vehicle control device 1 of this embodiment will be described. As shown in Fig. 1, the hybrid vehicle 10 has an engine 11, a transmission 12, a motor 13, a battery 14, front tires 15 (non-driven wheels), rear tires 16 (driven wheels), an ECU 17, and the like.

[0017] The engine 11 is a power source for the motor 13 and is connected to the motor 13 via the transmission 12 .

[0018] The motor 13 is disposed at a position closer to the rear tires 16 than the transmission 12, i.e., on the opposite side of the engine 11 from the transmission 12, and is connected to the rear tires 16 via a drive shaft 18, a differential gear 19, and an axle 20. The motor 13 functions as a generator that generates mechanical power from electrical energy, and as a generator that generates electrical energy from mechanical energy.

[0019] That is, the motor 13 functions as a generator that generates power (that is, mechanical power) for propelling the hybrid vehicle 10 using the power (that is, electrical energy) supplied from the battery 14.

[0020] The motor 13 also functions as a generator that generates electricity (i.e., performs regenerative power generation) by utilizing the rotational power (i.e., mechanical energy) transmitted from the rear tires 16, and charges the power (i.e., electrical energy) into the battery 14. The motor 13 is a three-phase motor.

[0021] The battery 14 is connected to the motor 13. The battery 14 supplies electric power to the motor 13 to discharge the electric power, and receives electric power from the motor 13 to charge the electric power.

[0022] The ECU 17 is a control unit that controls the components of the hybrid vehicle 10 (for example, the engine 11, the transmission 12, the motor 13, etc.), and includes a central processing unit (CPU), various memories, an external input circuit, an external output circuit, and the like.

[0023] <Explanation of the motor, inverter and battery> As shown in FIG. 2, the motor 13 is electrically connected to the battery 14 via an inverter 21, and the inverter 21 performs regeneration control and power running control.

[0024] As shown in FIG. 1, a charge amount sensor 22 (an example of a "charge amount value acquisition unit" in the present disclosure) that acquires the value of the charge amount of the battery 14 is connected to the battery 14.

[0025] 2, a current sensor 23 (an example of a "regenerative current value acquisition unit" in the present disclosure) that acquires a value of regenerative current Ib is provided between the motor 13 (more specifically, the inverter 21) and the battery 14. Furthermore, as shown in Fig. 2 and Fig. 3, phase current sensors 24u, 24v, and 24w that detect phase currents Iu, Iv, and Iw output from the motor 13 are provided between the motor 13 and the inverter 21.

[0026] <Control performed by the control device of a hybrid vehicle> Next, the control performed by the control device 1 for the hybrid vehicle, that is, the control performed by the ECU 17 will be described.

[0027] As shown in Fig. 1, the motor 13 is connected to the rear tires 16, so when the regeneration conditions are met, the motor 13 rotates in accordance with the rotation of the rear tires 16. In this way, the motor 13 performs regenerative power generation, which generates electricity using the rotational power transmitted from the rear tires 16. The regenerative current obtained by the regenerative power generation flows into the battery 14, thereby charging the battery 14. In this way, the regenerative control is performed.

[0028] However, when the charge amount of the battery 14 is close to the full charge amount (i.e., the charging rate is 100%), if the regenerative control is performed to charge the battery 14, the battery 14 may be overcharged. If this happens, the battery 14 may be deteriorated.

[0029] Therefore, in this embodiment, the ECU 17 performs regenerative control when the charge level of the battery 14 is not close to the full charge level, while performing regenerative inhibition control (an example of the "charge prevention control" of the present disclosure) described later when the charge level of the battery 14 is close to the full charge level so as not to perform regenerative control.

[0030] Specifically, the ECU 17 performs the control shown in Fig. 4. As shown in Fig. 4, the ECU 17 determines whether or not a regeneration condition is satisfied (step S1). Here, the regeneration condition is, for example, a condition that the accelerator opening is 0% (i.e., the depression amount of the accelerator pedal (not shown) is 0) or a condition that the brake pedal (not shown) is operated.

[0031] If the regeneration condition is met (step S1: YES), the ECU 17 determines whether the charge amount of the battery 14 (indicated as "battery remaining amount" in the drawing) acquired by the charge amount sensor 22 is equal to or greater than a predetermined threshold (e.g., the charging rate of the battery 14 is 90% or greater) (i.e., whether the charge amount of the battery 14 is close to full charge) (step S2). If the regeneration condition is not met (step S1: NO), the ECU 17 ends the control process.

[0032] Then, in step S2, if the charge amount of the battery 14 is less than the predetermined threshold (step S2: NO), that is, if the charge amount of the battery 14 is not close to full charge, the ECU 17 performs regeneration control (step 3).

[0033] Here, the regenerative control is a control for charging the battery 14 with electric power obtained by the motor 13 performing regenerative power generation. Specifically, in the regenerative control, as shown in FIG. 5(b), the inverter 21 generates a phase voltage Vu lower than the induced voltage ωφ generated by the motor 13. As a result, as shown in FIG. 5(a) and FIG. 6, a phase current Iu is generated due to the difference between the induced voltage ωφ and the phase voltage Vu, and as shown in FIG. 5(c) and FIG. 7, a regenerative current Ib is generated as a battery current (i.e., a current flowing to the battery 14). The regenerative current Ib thus generated flows to the battery 14, thereby charging the battery 14. Note that the phase voltages Vv and Vw are also generated by the inverter 21 in the same manner, so that the phase currents Iv and Iw are generated, and the regenerative current Ib is generated as a battery current.

[0034] Returning to the explanation of FIG. 4, on the other hand, if the charge amount of the battery 14 is equal to or greater than the predetermined threshold in step S2 (step S2: YES), that is, if the charge amount of the battery 14 is close to full charge, the ECU 17 performs regeneration inhibition control (step 4).

[0035] Here, the regeneration inhibition control is a control that does not allow the battery 14 to be charged with the electric power obtained by the motor 13 performing regenerative power generation. Specifically, as shown in FIG. 9, feedback control is performed so that the phase currents Iu, Iv, and Iw output by the motor 13 become zero. More specifically, in the regeneration inhibition control, as shown in FIG. 8(b), the inverter 21 generates a phase voltage Vu that is the same as the induced voltage ωφ generated by the motor 13. As a result, as shown in FIG. 8(a) and FIG. 10, there is no difference between the induced voltage ωφ and the phase voltage Vu, so that the phase current Iu is not generated, and as shown in FIG. 8(c) and FIG. 11, the regenerative current Ib is not generated as the battery current. Therefore, the regenerative current Ib does not flow to the battery 14, so that the battery 14 can be prevented from being charged. Note that, by similarly generating the phase voltages Vv and Vw by the inverter 21, the phase currents Iv and Iw are not generated, and the regenerative current Ib is not generated as the battery current, so that the battery 14 can be prevented from being charged.

[0036] As described above, in this embodiment, when the motor 13 performs regenerative power generation under a condition in which the value of the charge amount of the battery 14 acquired by the charge amount sensor 22 is equal to or greater than a predetermined threshold, the ECU 17 performs regeneration inhibition control to prevent charging of the battery 14. In this regeneration inhibition control, the inverter 21 generates phase voltages Vu, Vv, Vw having the same magnitude as the induced voltage ωφ generated in the motor 13 by regenerative power generation, thereby preventing the regenerative current Ib obtained by regenerative power generation from flowing to the battery 14, thereby preventing charging of the battery 14.

[0037] In this way, when the charge amount value of the battery 14 is equal to or greater than a predetermined threshold value close to full charge, even if the regeneration condition is met and the motor 13 performs regenerative power generation, the regenerative current Ib does not flow to the battery 14, preventing the battery 14 from being charged. This makes it possible to prevent the battery 14 from being overcharged. This makes it possible to prevent the battery 14 from deteriorating.

[0038] Thus, in this embodiment, the ECU 17 performs regeneration inhibition control when it is not desired to charge the battery 14, that is, when the charge amount of the battery 14 is equal to or greater than a predetermined threshold and the motor 13 performs regenerative power generation. As a modified example, the ECU 17 may perform regeneration inhibition control when it is not desired to charge the battery 14, that is, when the temperature of the battery 14 is equal to or greater than a predetermined temperature.

[0039] Second Embodiment Next, the second embodiment will be described with respect to the points that differ from the first embodiment.

[0040] When the regeneration inhibition control is performed, for example, if an error is superimposed on the detection value of the phase current sensor 24u, the value of the phase current Iu (indicated as "microcomputer recognized value" in the figure) acquired and recognized by the ECU 17 from the phase current sensor 24u may be 0 [A] as shown in FIG. 15(a), but the phase current Iu may actually flow. In this case, since the phase voltage Vu is output while feeding back the phase current Iu, a difference between the induced voltage ωφ and the phase voltage Vu occurs as shown in FIG. 15(b). Then, due to the difference between the induced voltage ωφ and the phase voltage Vu thus generated, a regenerative current Ib may be generated as a battery current as shown in FIG. 15(c). The same applies to the case where an error is superimposed on the detection value of the phase current sensor 24v or the phase current sensor 24w.

[0041] Therefore, in this embodiment, when regeneration prohibition control is being implemented and an error is superimposed on the detection values ​​of the phase current sensors 24u, 24v, and 24w, in order to prevent a regenerative current Ib from being generated as a battery current and charging the battery 14, the control shown in Figure 12 is performed.

[0042] As shown in FIG. 12, different from FIG. 4, when the ECU 17 performs the regeneration prohibition control (step S104), it determines whether or not the regeneration current Ib detected by the current sensor 23 is 0 [A] (step S105).

[0043] If the regenerative current Ib is not 0 [A] (step S105: NO), the ECU 17 performs battery current 0A (zero ampere) control (an example of the "zero regenerative current control" of the present disclosure) (step S106).

[0044] Here, the battery current 0A control is a control represented by the block diagram shown in Fig. 14, and as shown in Fig. 13 (after the time indicated as "battery current feedback ON" in the figure), feedback control of the regenerative current Ib is performed by adjusting the phase voltage Vu generated by the inverter 21 based on the value of the regenerative current Ib acquired by the current sensor 23 so that it is equal to the induced voltage ωφ, and the value of the regenerative current Ib acquired by the current sensor 23 becomes 0. Note that the phase voltages Vv and Vw generated by the inverter 21 are also adjusted in a similar manner to perform feedback control of the regenerative current Ib.

[0045] As described above, in this embodiment, when regeneration inhibition control is executed, the ECU 17 adjusts the phase voltages Vu, Vv, Vw generated by the inverter 21 based on the value of the regenerative current Ib acquired by the current sensor 23, and performs battery current 0A control, which performs feedback control so that the value of the regenerative current Ib becomes zero.

[0046] This makes it possible to more reliably prevent the battery 14 from being charged when the regeneration inhibition control is executed, even if errors are superimposed on the detection values ​​of the phase current sensors 24u, 24v, 24w.

[0047] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way. Needless to say, various improvements and modifications are possible without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0048] 1. Hybrid vehicle control device 10 Hybrid vehicles 11 Engine 13 Motor 14 Battery 16 Rear tires 17 ECU 21 Inverter 22 Charge level sensor 23 Current Sensor 24u, 24v, 24w phase current sensor ωφ Induced voltage Vu, Vv, Vw phase voltages Iu,Iv,Iw Phase current Ib regenerative current

Claims

1. a motor connected to a tire, regeneratively controlled and powered by an inverter, and configured to generate electricity by utilizing rotational power transmitted from the tire; a battery connected to the inverter; A control unit that controls an electric vehicle; A control device for an electric vehicle having the control unit, when the motor performs the regenerative power generation under a condition where charging of the battery is not desired, generates a voltage in the inverter that is the same magnitude as an induced voltage generated in the motor by the regenerative power generation, thereby preventing a regenerative current obtained by the regenerative power generation from flowing to the battery, thereby performing a charging prevention control to prevent charging of the battery; A control device for an electric vehicle, comprising:

2. The control device for an electric vehicle according to claim 1, a charge amount value acquisition unit that acquires a value of the charge amount of the battery; The situation in which charging of the battery is not desired is a situation in which the value of the charge amount of the battery acquired by the charge amount value acquisition unit is equal to or greater than a predetermined threshold value that is close to full charge; A control device for an electric vehicle, comprising:

3. The control device for an electric vehicle according to claim 1 or 2, a regenerative current value acquisition unit that acquires a value of the regenerative current, the control unit, when executing the charging prevention control, adjusts a voltage generated by the inverter based on the value of the regenerative current acquired by the regenerative current value acquisition unit, thereby performing a regenerative current zero control that performs feedback control so that the value of the regenerative current becomes zero; A control device for an electric vehicle comprising:

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