electric vehicles

Abstract

To provide a new technique for suppressing vibration generated in an electric vehicle being stopped.SOLUTION: An electric vehicle is provided with: a motor; a battery that supplies the motor with electric power; an inverter, provided between the battery and the motor, which converts DC power from the battery to AC power to be supplied to the motor; and a control device that controls operation of the inverter. The control device can execute specific operation involving distribution of power to the motor, while stopping the electric vehicle. The specific operation has a step of determining a target electric angle with respect to an electric angle of the motor, on the basis of an initial value of the electric angle; a step of controlling operation of the inverter, so that distribution of prescribed rated currents to the motor is started; and a step of identifying torque generated in the motor, on the basis of the rated currents and a current value of the electric angle, determining feedback torque for damping, on the basis of a deviation of the current value with respect to the target electric angle, and controlling currents distributed to the motor, on the basis of the generated torque, the feedback torque and the rated currents.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The technology disclosed in this specification relates to electric vehicles.

Background Art

[0002] Patent Document 1 discloses an electric vehicle including a motor that drives the wheels of the electric vehicle, a battery that supplies power to the motor, an inverter provided between the battery and the motor that converts DC power from the battery into AC power supplied to the motor, and a control device that controls the operation of the inverter.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an electric vehicle, power may be supplied to the motor while the electric vehicle is stopped. When power is supplied to the motor, a generated torque corresponding to the electrical angle of the motor occurs. Note that there is also an electrical angle at which no torque occurs even when power is supplied to the motor. When a generated torque occurs in the motor, the electrical angle of the motor fluctuates around the electrical angle at which no torque occurs. Accordingly, torque fluctuation occurs in the motor, and the electric vehicle vibrates. In the electric vehicle of Patent Document 1, vibration occurring in the stopped electric vehicle is suppressed by adjusting the electrical angle when the electric vehicle stops.

[0005] This specification provides a novel technology for suppressing vibration occurring in a stopped electric vehicle.

Means for Solving the Problems

[0006] In a first aspect disclosed herein, the electric vehicle comprises a motor for driving the wheels of the electric vehicle, a battery for supplying power to the motor, an inverter provided between the battery and the motor for converting DC power from the battery into AC power supplied to the motor, and a control device for controlling the operation of the inverter, wherein the control device is capable of performing a specific operation involving energizing the motor while the electric vehicle is stopped, and the specific operation may include the steps of: determining a target electrical angle relative to the electrical angle based on an initial value of the electrical angle of the motor; controlling the operation of the inverter to start energizing the motor at a predetermined rated current; identifying the generated torque generated in the motor based on the rated current and the current value of the electrical angle; determining a vibration damping feedback torque based on the deviation of the current value relative to the target electrical angle; and controlling the current supplied to the motor based on the generated torque, the feedback torque and the rated current.

[0007] According to the above configuration, the control device controls the current supplied to the motor based on the generated torque, feedback torque, and rated current. In this case, the motor's electrical angle can be brought closer to the target electrical angle. The target electrical angle is set to the electrical angle at which the generated torque when the motor is energized is approximately zero. This reduces the generated torque and suppresses fluctuations in the generated torque. Therefore, vibrations occurring in a stationary electric vehicle can be suppressed.

[0008] In a second embodiment, in the first embodiment, the control device may determine a target value for the current when controlling the current by dividing the sum of the generated torque and the feedback torque by the generated torque.

[0009] The generated torque is proportional to the current. Therefore, the magnitude of the generated torque can be adjusted by adjusting the magnitude of the current. By adjusting the magnitude of the generated torque, the motor's electrical angle can be brought closer to the target electrical angle more quickly. Consequently, vibrations occurring in a stationary electric vehicle can be suppressed more quickly.

[0010] In a third embodiment, another electric vehicle comprises a motor that drives the wheels of the electric vehicle, a battery that supplies power to the motor, an inverter provided between the battery and the motor that converts DC power from the battery into AC power supplied to the motor, and a control device that controls the operation of the inverter, wherein the control device is capable of performing a specific operation involving energizing the motor while the electric vehicle is stopped, and the specific operation includes the steps of controlling the operation of the inverter to start energizing the motor at a predetermined rated current, identifying the generated torque generated in the motor based on the rated current and the current value of the electrical angle of the motor, determining a vibration damping feedback torque based on the angular velocity of the electrical angle, and controlling the current supplied to the motor based on the generated torque, the feedback torque and the rated current.

[0011] According to the above configuration, the control device controls the current supplied to the motor based on the generated torque, feedback torque, and rated current. In this case, the electrical angle of the motor can be brought close to the electrical angle at which the generated torque when the motor is energized is approximately zero. This reduces the generated torque and suppresses fluctuations in the generated torque. Therefore, vibrations occurring in a stationary electric vehicle can be suppressed.

[0012] In the fourth embodiment, in the third embodiment, when the control device controls the energizing current, it determines a target value for the energizing current according to the ratio obtained by dividing the sum of the generated torque and the feedback torque by the generated torque.

[0013] The generated torque is proportional to the current. Therefore, the magnitude of the generated torque can be adjusted by adjusting the magnitude of the current. By adjusting the magnitude of the generated torque, the motor's electrical angle can be brought closer to the target electrical angle more quickly. Consequently, vibrations occurring in a stationary electric vehicle can be suppressed more quickly.

[0014] In the fifth embodiment, in any one of the first to fourth embodiments described above, the specific operation may be a battery heating operation for the purpose of raising the temperature of the battery, or a neutral point charging operation for charging the battery by connecting an external power supply to the neutral point of the motor.

[0015] According to the above configuration, vibrations in the electric vehicle can be suppressed when the battery temperature rise operation or neutral point charging operation is being performed. [Brief explanation of the drawing]

[0016] [Figure 1] The circuit diagram for charging system 2 is shown. [Figure 2] An example of torque map 64 is shown. [Figure 3] A flowchart of the current control process according to the first embodiment is shown. [Figure 4] The change in electrical angle when a neutral point charging operation is performed in the electric vehicle relating to the comparative example is shown. [Figure 5] The change in electrical angle when a neutral point charging operation is performed in the electric vehicle 10 according to the first embodiment is shown. [Figure 6] A flowchart of the current control process according to the second embodiment is shown. [Modes for carrying out the invention]

[0017] (First embodiment) As shown in FIG. 1, the charging system 2 includes an electric vehicle 10 and a charging device 100. The electric vehicle 10 includes a battery 12, a system main relay 14, a traveling smoothing capacitor 16, an inverter 20, a motor 30, a charging circuit 40, a charging inlet 50, and a control device 60. The charging inlet 50 is detachably connected to the charging device 100 and receives charging power for charging the battery 12.

[0018] The battery 12 is a rechargeable secondary battery that incorporates a plurality of secondary battery cells (not shown), such as lithium-ion cells for example, and is configured to be repeatedly charged and discharged, typically a lithium-ion battery. The battery 12 is connected to the inverter 20 via the system main relay 14. The operation of the system main relay 14 is controlled by the control device 60. The traveling smoothing capacitor 16 is provided between the battery 12 and the inverter 20.

[0019] The inverter 20 is provided between the traveling smoothing capacitor 16 and the motor 30. The inverter 20 is a device that converts DC power from the battery 12 into AC power. The inverter 20 includes three upper switching elements 22UH, 22VH, 22WH and three lower switching elements 22UL, 22VL, 22WL. Hereinafter, the "switching element" is denoted as "SW element". The upper SW elements 22UH, 22VH, 22WH are each connected in series to the lower SW elements 22UL, 22VL, 22WL.

[0020] The midpoint between the upper SW element 22UH and the lower SW element 22UL connected in series is electrically connected to the U-phase terminal 32 of the motor 30. Thus, the upper SW element 22UH and the lower SW element 22UL constitute a pair of upper and lower U-phase arms that connect the U-phase terminal 32 of the motor 30 to the positive or negative electrode of the battery 12. Similarly, the upper SW element 22VH and the lower SW element 22VL connected in series constitute a pair of upper and lower V-phase arms, and the midpoint between them is electrically connected to the V-phase terminal 34 of the motor 30. Also, the upper SW element 22WH and the lower SW element 22WL connected in series constitute a pair of upper and lower W-phase arms, and the midpoint between them is electrically connected to the W-phase terminal 36 of the motor 30. The operations of the three lower SW elements 22UL, 22VL, and 22WL, and the operations of the three lower SW elements 22UL, 22VL, and 22WL are controlled by the control device 60.

[0021] The motor 30 is a three-phase alternating current motor that drives the front wheels of the electric vehicle 10 using the power supplied from the battery 12. The motor 30 includes a U-phase coil 32A, a V-phase coil 34A, and a W-phase coil 36A. One end of each of the U-phase coil 32A, the V-phase coil 34A, and the W-phase coil 36A is connected to the U-phase terminal 32, the V-phase terminal 34, and the W-phase terminal 36, respectively. The other ends of the U-phase coil 32A, the V-phase coil 34A, and the W-phase coil 36A are connected to each other at the neutral point 30A. The motor 30 further includes an electrical angle sensor 38 that detects the electrical angle of the rotor (not shown) of the motor 30.

[0022] The charging circuit 40 is a circuit for supplying the power from the charging device 100 to the battery 12. The charging circuit 40 includes a first charging relay 42, a charging smoothing capacitor 44, and a second charging relay 46. The charging smoothing capacitor 44 is provided between the motor 30 and the charging inlet 50. The first charging relay 42 is provided between the neutral point 30A of the motor 30 and the first charging relay 42. The second charging relay 46 is provided between the charging inlet 50 and the charging smoothing capacitor 44. The operations of the first charging relay 42 and the second charging relay 46 are controlled by the control device 60.

[0023] The control device 60 is a computer equipped with a CPU. The control device 60 controls the operation of each component of the electric vehicle 10. The control device 60 is equipped with a memory 62 that stores a torque map 64. As shown in Figure 2, the torque map 64 is information that shows the relationship between the electrical angle [°] of the motor 30 and the generated torque [Nm]. The generated torque is the torque that is generated in the motor 30 when power is supplied to the motor 30. The torque map 64 is information used in the current supply control processing (Figure 3) which will be described later. The magnitude of the generated torque is proportional to the current value supplied to the motor 30. The torque map 64 is information that corresponds to the rated current Ir of the motor 30 in the neutral point charging operation which will be described later.

[0024] The control device 60 in Figure 1 is configured to perform a neutral point charging operation that energizes the motor 30 while the electric vehicle 10 is stopped. The neutral point charging operation is an operation to charge the battery 12 by boosting the voltage of the charging power received from the charging device 100. The control device 60 performs the neutral point charging operation when the charging device 100 is connected to the charging inlet 50 and the voltage of the charging power received from the charging device 100 (e.g., 400V) is lower than the rated voltage of the battery 12 (e.g., 800V).

[0025] The neutral point charging operation will now be described. As shown in Figure 1, the control device 60 electrically connects the system main relay 14, the first charging relay 42, and the second charging relay 46. The control device 60 then performs a boost operation to charge the battery 12. Specifically, the control device 60 keeps the upper SW elements 22UH, 22VH, and 22WH in the OFF state and repeatedly switches at least one of the lower SW elements 22UL, VL, and WL on and off. The control device 60 controls the duty cycle of the lower SW element being switched on and off. The control device 60 may also symmetrically switch the upper SW elements 22UH, 22VH, and 22WH on and off in synchronization with the lower SW elements 22UL, VL, and WL being repeatedly switched on and off. For example, the case where the lower SW element 22UL is switched on and off will be described. When the lower SW element 22UL is ON, current flows through the U-phase coil 32A and the lower SW element 22UL. Energy is stored in the U-phase coil 32A. When the lower SW element 22UL is turned off in this state, the energy stored in the U-phase coil 32A is superimposed on the power from the charging device 100. As a result, the voltage of the power supplied from the inverter 20 to the battery 12 is increased. This charges the battery 12.

[0026] (Current control processing; Figure 3) Referring to Figure 3, the energizing current control process performed during neutral point charging operation will be described. The energizing current control process is a process for controlling the energizing current I supplied to the motor 30 during neutral point charging operation. The control device 60 starts the process shown in Figure 3 at the same time as the neutral point charging operation begins.

[0027] In S10, the control device 60 determines the electrical angle of the motor 30 at the start of the neutral point charging operation (hereinafter referred to as "initial electrical angle φs"). The initial electrical angle φs is the initial value of the electrical angle of the motor 30.

[0028] In S12, the control device 60 determines the target electrical angle φt using the torque map 64 stored in the memory 62 and the initial electrical angle φs identified in S10. The control device 60 identifies the electrical angle closest to the initial electrical angle φs from among a plurality of electrical angles in which the generated torque is zero as the target electrical angle φt. For example, if the initial electrical angle φs is 110°, 120° is determined as the target electrical angle φt. In a modified example, the target electrical angle φt may be the electrical angle in which the generated torque when the motor 30 is energized is less than or equal to a predetermined torque.

[0029] In S14, the control device 60 controls the operation of the inverter 20 to start supplying power to the motor 30. The control device 60 determines the rated current Ir as the target value It of the supplying current I, and controls the operation of the inverter 20 so that it becomes the target value It.

[0030] In S20, the control device 60 determines the current electrical angle φp of the motor 30.

[0031] In S22, the control device 60 determines whether the absolute value of the electrical angle difference, obtained by subtracting the current electrical angle φp from the target electrical angle φt, has been less than a first predetermined value Va for a first predetermined time or longer. The first predetermined value Va is a positive value. If the absolute value of the electrical angle difference has been less than the first predetermined value Va for a first predetermined time or longer (YES in S22), the control device 60 terminates the process shown in Figure 3. After terminating the process shown in Figure 3, the control device 60 continues the neutral point charging operation with the rated current Ir as the target value It. On the other hand, if the absolute value of the electrical angle difference has not been less than the first predetermined value Va for a first predetermined time or longer (NO in S22), the control device 60 proceeds to S30.

[0032] In S30, the control device 60 determines the feedback torque Tf using the target electrical angle φt and the current electrical angle φp. Hereinafter, the feedback torque will be referred to as "FB torque". The FB torque Tf is the torque used to dampen vibrations occurring in the stationary electric vehicle 10. The control device 60 determines the FB torque Tf by multiplying the value obtained by subtracting the target electrical angle φt from the current electrical angle φp by a second predetermined value Vb. The second predetermined value Vb is a negative value.

[0033] In S32, the control device 60 determines the generated torque Tc using the rated current Ir, the torque map 64, and the current electrical angle φp.

[0034] In S34, the control device 60 calculates the output torque To. The control device 60 calculates the output torque To by adding the generated torque Tc to the FB torque Tf.

[0035] In S36, the control device 60 calculates the torque ratio R, which is the ratio obtained by dividing the output torque To by the generated torque Tc. That is, the torque ratio R is the ratio obtained by dividing the sum of the generated torque Tc and the FB torque Tf by the generated torque Tc.

[0036] In S40, the control device 60 determines whether the torque ratio R exceeds "1". If the torque ratio R exceeds "1" (YES in S40), the control device 60 proceeds to S42. On the other hand, if the torque ratio R is "1" or less (NO in S40), the control device 60 proceeds to S44.

[0037] In S42, the control device 60 determines the rated current Ir as the target value It. When S42 is completed, the control device 60 proceeds to S50.

[0038] In S44, the control device 60 determines whether the torque ratio R is greater than "0 (zero)". If the torque ratio R is greater than "0" (YES in S44), the control device 60 proceeds to S46. On the other hand, if the torque ratio R is less than or equal to "0" (NO in S44), the control device 60 proceeds to S48.

[0039] In S46, the control device 60 determines the target value It as the value obtained by multiplying the rated current Ir by the torque ratio R (R*Ir). In this case, the target value It is less than or equal to the rated current Ir. When S46 is completed, the control device 60 proceeds to S50.

[0040] In S48, the control device 60 determines the current value "0 (zero)" as the target value It. When S48 is completed, the control device 60 proceeds to S50.

[0041] In S50, the control device 60 controls the current I to reach the predetermined target value It. When S50 is completed, the control device 60 returns to S20.

[0042] As described above, the control device 60 executes the processes S30 to S50 until it determines YES in S22.

[0043] The effects of the energizing current control process (see Figure 3) will be explained with reference to Figures 4 and 5. The vertical axis of the time charts in Figures 4 and 5 represents the electrical angle of the motor 30. In the initial state of Figures 4 and 5, the electrical angle of the motor 30 of the stationary electric vehicle 10 is 117°. Figure 4 shows the change in the electrical angle in the comparative example electric vehicle, and Figure 5 shows the change in the electrical angle in the electric vehicle 10 of this embodiment. The comparative example electric vehicle has the same configuration as the electric vehicle 10, except that it does not perform the energizing current control process (see Figure 3).

[0044] In Figure 4, when the neutral point charging operation begins, the comparative example's electric vehicle starts supplying power to the motor. As shown in Figure 2, the generated torque Tc is a positive value when the motor's electrical angle is 117°. Therefore, as shown in Figure 4, when power is supplied to the motor, a positive generated torque Tc is generated in the motor, and the motor's electrical angle increases. Then, (1) when the motor's electrical angle exceeds 120°, a negative generated torque Tc is generated in the motor. Therefore, the motor's electrical angle decreases. Then, (2) when the motor's electrical angle becomes less than 120°, a positive generated torque Tc is generated in the motor, and the motor's electrical angle increases. After that, (1) and (2) are repeated. That is, the motor's electrical angle fluctuates approximately centered at 120°. Accordingly, torque fluctuations occur in the motor, and the comparative example's electric vehicle vibrates. In addition, the torque fluctuations of the motor may also cause a gear-clapping noise in the drive system of the comparative example's electric vehicle.

[0045] In Figure 5, when the neutral point charging operation is started, the electric vehicle 10 determines the initial electrical angle φs (117°) (S10 in Figure 3), sets 120° as the target electrical angle φt (S12), and starts energizing the motor 30 (S14). Similar to the comparative example in Figure 4, when energizing the motor 30 is started, a positive generated torque Tc is produced in the motor 30, and the electrical angle of the motor 30 increases. In the energizing current control process (see Figure 3), if the current electrical angle φp of the motor 30 is 120° or less, the FB torque Tf becomes a positive value (S30). Therefore, the torque ratio R becomes greater than 1 (YES in S40), and the target value It becomes the rated current Ir (S42). Also, if the current electrical angle φp is greater than 120°, the FB torque Tf becomes a negative value (S22). Therefore, the torque ratio R becomes less than 1 (NO in S40, YES in S44). In this case, the torque ratio R is greater than zero. Therefore, the target value It becomes "R*Ir" (S46). As a result, when the current electrical angle φp is greater than 120°, the target value It becomes smaller than the rated current Ir, and the absolute value of the torque Tc generated by the motor 30 becomes smaller than the absolute value of the torque Tc generated when the target value It is the rated current Ir. As the absolute value of the generated torque Tc decreases, the amplitude of the electrical angle decreases compared to when the target value It is the rated current Ir. And as the amplitude of the electrical angle decreases, the absolute value of the generated torque Tc when the electrical angle is 120° or less also decreases. In this way, as the amplitude of the electrical angle decreases, fluctuations in the electrical angle of the motor 30 are suppressed, and the electrical angle approaches the target electrical angle φt. As a result, vibrations of the electric vehicle 10 are damped. Also, the gear noise of the drive system of the electric vehicle 10 is suppressed.

[0046] As described above, the electric vehicle 10 includes a motor 30 that drives the front wheels (an example of "wheels") of the electric vehicle 10, a battery 12 that supplies power to the motor 30, an inverter 20 provided between the battery 12 and the motor 30 that converts DC power from the battery 12 into AC power supplied to the motor 30, and a control device 60 that controls the operation of the inverter 20. The control device 60 is capable of performing a neutral point charging operation (an example of "specific operation") that involves energizing the motor 30 while the electric vehicle 10 is stopped. The neutral point charging operation involves the steps of: determining a target electrical angle φt based on an initial electrical angle φs (an example of "initial value of the motor's electrical angle") (S12 in Figure 2); controlling the operation of the inverter 20 to start energizing the motor 30 with a predetermined rated current Ir (S14); identifying the generated torque Tc generated in the motor 30 based on the rated current Ir and the current electrical angle φp (an example of "current value of the electrical angle") (S32); determining the FB torque Tf based on the deviation of the current electrical angle φp from the target electrical angle φt (S30); and controlling the energizing current I to the motor 30 based on the generated torque Tc, FB torque Tf, and rated current Ir (S30-S50).

[0047] According to the above configuration, the control device 60 controls the current I supplied to the motor 30 based on the generated torque Tc, the FB torque Tf, and the rated current Ir. In this case, the electrical angle of the motor 30 can be brought closer to the target electrical angle φt. This reduces the generated torque Tc and suppresses fluctuations in the generated torque Tc. Therefore, vibrations occurring in the stationary electric vehicle 10 during neutral point charging operations can be suppressed.

[0048] Furthermore, when the control device 60 controls the energizing current I, it determines a target value It for the energizing current I according to the torque ratio R, which is the ratio obtained by dividing the sum of the generated torque Tc and the FB torque Tf by the generated torque Tc (S40~S48).

[0049] The generated torque Tc is proportional to the current I. Therefore, the magnitude of the generated torque Tc can be adjusted by adjusting the magnitude of the current I. By adjusting the magnitude of the generated torque Tc, the electrical angle of the motor 30 can be brought closer to the target electrical angle φt at an earlier stage. Consequently, vibrations occurring in the stationary electric vehicle 10 can be suppressed at an earlier stage.

[0050] (Second example) The electric vehicle 10 of the second embodiment differs in that it performs the energizing current control process shown in Figure 6 instead of the energizing current control process shown in Figure 3.

[0051] (Current control processing; Figure 6) Referring to Figure 6, the current control process performed during the neutral point charging operation will be described. S114 is the same as S14 in Figure 3.

[0052] In S120, the control device 60 determines the angular velocity ω of the motor 30.

[0053] In S122, the control device 60 determines whether the absolute value of the angular velocity ω is less than the third predetermined value Vc for a second predetermined time or longer. The third predetermined value Vc is a positive value. If the absolute value of the angular velocity ω is less than the third predetermined value Vc for a second predetermined time or longer (YES in S122), the control device 60 terminates the process shown in Figure 6. After terminating the process shown in Figure 6, the control device 60 continues the neutral point charging operation with the rated current Ir as the target value It for the energizing current I. On the other hand, if the absolute value of the angular velocity ω is not less than the third predetermined value Vc for a second predetermined time or longer (NO in S122), the control device 60 proceeds to S130.

[0054] In S130, the control device 60 determines the FB torque Tf using the angular velocity ω. The control device 60 determines the FB torque Tf by multiplying the angular velocity ω by a fourth predetermined value Vd. The fourth predetermined value Vd is a negative value.

[0055] Steps S132 to S150 are the same as steps S32 to S50 in Figure 3.

[0056] In this embodiment, vibrations of the electric vehicle 10 during neutral point charging can be suppressed by determining the FB torque Tf using the angular velocity ω.

[0057] As described above, the electric vehicle 10 includes a motor 30 that drives the front wheels of the electric vehicle 10, a battery 12 that supplies power to the motor 30, an inverter 20 provided between the battery 12 and the motor 30 that converts DC power from the battery 12 into AC power supplied to the motor 30, and a control device 60 that controls the operation of the inverter 20. The control device 60 can perform a neutral point charging operation that involves energizing the motor 30 while the electric vehicle 10 is stopped. The neutral point charging operation involves controlling the operation of the inverter 20 to start energizing the motor 30 with a predetermined rated current Ir (S114), identifying the generated torque Tc generated in the motor 30 based on the rated current Ir and the current ω of the motor 30 (S132), determining the vibration damping FB torque Tf based on the current angular velocity ω (S130), and controlling the current I supplied to the motor 30 based on the generated torque Tc, FB torque Tf and rated current Ir (S140~S150).

[0058] According to the above configuration, the control device 60 controls the current I supplied to the motor 30 based on the generated torque Tc, the FB torque Tf, and the rated current Ir. In this case, the electrical angle of the motor 30 can be brought close to the electrical angle at which the generated torque when the motor 30 is energized is approximately zero. This reduces the generated torque Tc and suppresses fluctuations in the generated torque Tc. Therefore, vibrations occurring in the stationary electric vehicle 10 can be suppressed.

[0059] Furthermore, when the control device 60 controls the energizing current I, it determines a target value It for the energizing current I according to the torque ratio R, which is the ratio obtained by dividing the sum of the generated torque Tc and the FB torque Tf by the generated torque Tc.

[0060] The generated torque Tc is proportional to the current I. Therefore, the magnitude of the generated torque Tc can be adjusted by adjusting the magnitude of the current I. By adjusting the magnitude of the generated torque Tc, the electrical angle of the motor 30 can be brought closer to the target electrical angle φt at an earlier stage. Consequently, vibrations occurring in the stationary electric vehicle 10 can be suppressed at an earlier stage.

[0061] The specific examples of the technology disclosed herein have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above. Modifications of the above embodiments are listed below.

[0062] The control device 60 may also be capable of performing a battery heating operation to raise the temperature of the battery 12 while the electric vehicle 10 is stopped. For example, in the battery heating operation, the control device 60 overheats the coolant of the drive system of the electric vehicle 10 by controlling the operation of the inverter 20 and the motor 30. Then, the heated coolant is used to raise the temperature of the battery 12. In this modified example, the control device 60 performs the energization current control process shown in Figure 3 or Figure 6 in the battery heating operation. With this configuration, vibrations of the electric vehicle 10 during the battery heating operation can be suppressed.

[0063] The technical elements described herein or in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated herein or in the drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of symbols]

[0064] 2: Charging system, 10: Electric vehicle, 12: Battery, 14: System main relay, 16: Driving smoothing capacitor, 20: Inverter, 22UH: Upper switch element, 22UL: Lower switch element, 22VH: Upper switch element, 22VL: Lower switch element, 22WH: Upper switch element, 22WL: Lower switch element, 30: Motor, 30A: Neutral point, 32: U-phase terminal, 32A: U-phase coil, 34: V-phase terminal, 34A: V-phase coil, 36: W-phase terminal, 36A: W-phase coil, 38: Electrical angle sensor, 40: Charging circuit, 42: First charging relay, 44: Charging smoothing capacitor, 46: Second charging relay, 50: Charging inlet, 60: Control device, 62: Memory, 64: Torque map

Claims

1. It is an electric vehicle, A motor that drives the wheels of the aforementioned electric vehicle, A battery that supplies power to the motor, An inverter is provided between the battery and the motor, which converts DC power from the battery into AC power supplied to the motor. The system includes a control device that controls the operation of the inverter, The control device is capable of performing specific operations involving the supply of power to the motor while the electric vehicle is stopped. The aforementioned specific operation is, Based on the initial value of the motor's electrical angle, the electrical angle at which the torque generated in the motor is approximately zero when power is supplied to the motor is determined as the target electrical angle. The operation of the inverter is controlled to start supplying power to the motor at a predetermined rated current. Based on the rated current and the current value of the electrical angle, the generated torque is determined. Based on the deviation of the current value from the target electrical angle, the feedback torque for vibration damping is determined. The current supplied to the motor is controlled based on the generated torque, the feedback torque, and the rated current, so that the electrical angle of the motor approaches the target electrical angle. Electric car.

2. The electric vehicle according to claim 1, wherein the control device determines a target value for the current when controlling the current, according to the ratio obtained by dividing the sum of the generated torque and the feedback torque by the generated torque.

3. It is an electric vehicle, A motor that drives the wheels of the aforementioned electric vehicle, A battery that supplies power to the motor, An inverter is provided between the battery and the motor, which converts DC power from the battery into AC power supplied to the motor. The system includes a control device that controls the operation of the inverter, The control device is capable of performing specific operations involving the supply of power to the motor while the electric vehicle is stopped. The aforementioned specific operation is, The operation of the inverter is controlled to start supplying power to the motor at a predetermined rated current. Based on the rated current and the current value of the motor's electrical angle, the torque generated by the motor is identified. Based on the angular velocity of the aforementioned electrical angle, the feedback torque for vibration damping is determined. The current supplied to the motor is controlled based on the generated torque, the feedback torque, and the rated current, so as to bring the electrical angle of the motor closer to the electrical angle at which the generated torque is approximately zero when the motor is energized. Electric car.

4. The electric vehicle according to claim 3, wherein the control device determines a target value for the current when controlling the current, according to the ratio obtained by dividing the sum of the generated torque and the feedback torque by the generated torque.

5. The electric vehicle according to any one of claims 1 to 4, wherein the specified operation is a battery heating operation for the purpose of raising the temperature of the battery, or a neutral point charging operation for charging the battery by connecting an external power supply to the neutral point of the motor.

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