JP2004096824A - Control method for electric vehicle and motor mounted thereon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent excessive current from being applied to a motor by deterring a wrong decision. <P>SOLUTION: When a motor current Im is not less than a threshold Iref and the variation dI of the motor current Im is not less than a threshold dIref(S132 and S134), the larger the motor current Im is (S138), the smaller the torque upper limit value Tmax is set, so that the torque to be outputted to a driving shaft form a motor is limited to be not more than the set torque upper limit value Tmax1. Since the decision is made, based on the motor current Im and the variation dI, wrong decision can be detected, as compared with the case of deciding it by only the motor current Im. Moreover, since smaller the torque upper limit value Tmax1 is set, the larger the motor current Im becomes, it can prevent excessive current from being applied to the motor, with higher certainty. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric vehicle and a method for controlling an electric motor mounted on the electric vehicle, and more particularly, to an electric vehicle including an electric motor capable of outputting power to a drive shaft connected to drive wheels and a method for controlling the electric motor mounted on the electric vehicle. About.
[0002]
[Prior art]
Conventionally, as an electric vehicle of this type, when an electric current value applied to a motor that outputs torque to a drive shaft becomes equal to or more than a predetermined value, an integration operation in control of the motor is stopped and a control amount is increased or decreased or fixed. Has been proposed (for example, see Patent Document 1). In this electric vehicle, by performing such control, an excessive current is prevented from being applied to the electric motor when the drive wheels idle.
[0003]
[Patent Document 1]
JP-A-2000-50419 (pages 4 to 5)
[0004]
[Problems to be solved by the invention]
However, in this electric vehicle, the overload of the electric motor is determined only by the current value applied to the electric motor. Therefore, when a detection signal detected as a current value is mixed with noise or a detection error, an erroneous determination may occur. is there. Further, when the current applied to the motor based on the idling of the drive wheels becomes equal to or more than a predetermined value, it is possible not only to prevent the excessive current from being applied to the motor but also to quickly converge the idling of the drive wheels. In addition, it is necessary to reflect the driver's intention even when the idling of the drive wheels converges.
[0005]
It is an object of the electric vehicle and the control method of the electric motor mounted on the electric vehicle of the present invention to suppress erroneous determination and more appropriately prevent excessive current from being applied to the electric motor. Another object of the present invention is to provide an electric vehicle and a method for controlling an electric motor mounted on the electric vehicle, in which the idling of the drive wheels is quickly converged. Further, the electric vehicle of the present invention and the control method of the electric motor mounted thereon have an object to output a torque reflecting the driver's intention to the drive shaft even when the idling of the drive wheels converges. One.
[0006]
[Means for Solving the Problems and Their Functions and Effects]
The electric vehicle and the control method of the electric motor mounted on the electric vehicle according to the present invention employ the following means in order to achieve at least a part of the above object.
[0007]
The electric vehicle of the present invention
An electric vehicle including an electric motor capable of outputting power to a drive shaft connected to drive wheels,
Drive control means for driving and controlling the motor so that torque is output from the motor to the drive shaft based on a driver's operation and a running state of the vehicle;
Current value detecting means for detecting a current value applied to the electric motor,
Change amount calculating means for calculating a change amount per unit time of the detected current value;
With
The drive control means, when the current value detected by the current value detection means is equal to or more than a predetermined current value and the change amount calculated by the change amount calculation means is equal to or more than a predetermined change amount, from the electric motor to the drive shaft It is a means to limit the output torque
That is the gist.
[0008]
In the electric vehicle of the present invention, when the current value applied to the motor is equal to or greater than the predetermined current value and the amount of change in the current value per unit time is equal to or greater than the predetermined amount, the torque output from the motor to the drive shaft is limited. Therefore, erroneous determination based on noise or a detection error can be suppressed as compared with the case where only an electric current value is applied to the electric motor, and an excessive current can be more appropriately prevented from being applied to the electric motor. Even if the torque is limited, if the torque based on the driver's operation and the running state of the vehicle is within the range of the torque limitation, the torque is output from the electric motor to the drive shaft, so that the driver's intention is Can be reflected.
[0009]
In such an electric vehicle of the present invention, the drive control means sets a first torque upper limit value based on the detected current value, and sets the torque output from the electric motor to the drive shaft to the set first torque upper limit value. It may be a means for restricting the value to be equal to or less than the value. In this way, the torque output from the motor to the drive shaft can be limited based on the current value applied to the motor.
[0010]
In the electric vehicle according to the aspect of the invention, in which the torque is limited using the first torque upper limit value set based on the current value, the drive control unit may be configured to decrease as the detected current value increases. It may be a means for setting one torque upper limit. With this configuration, the first torque upper limit value is set as the current value applied to the electric motor increases and the degree of the idling at the time of idling of the drive shaft increases, so that the idling of the drive shaft can be quickly converged.
[0011]
Further, in the electric vehicle according to the aspect of the invention, in which the torque is limited by using the first torque upper limit value set based on the current value, a rotation angular acceleration detecting means for detecting a rotation angular acceleration of the drive shaft; Slip detecting means for detecting slip due to idling of the drive wheel based on the detected rotational angular acceleration, wherein the drive control means detects the slip by the rotational angular acceleration detecting means when the slip detecting means detects the slip. Means for setting a second torque upper limit value based on the set rotational angular velocity, and limiting the torque output from the electric motor to the drive shaft so as to be equal to or less than the set second torque upper limit value. it can. In this case, the idle rotation of the drive wheels can be quickly converged based on the rotational angular acceleration of the drive shaft. In the electric vehicle according to the aspect of the present invention, the drive control means uses the relationship between the current value and the torque upper limit value used when setting the first torque upper limit value and sets the second torque upper limit value. The relationship between the rotational angular acceleration and the torque upper limit may be shared as the same relationship to set the first torque upper limit and the second torque upper limit. With this configuration, the first torque upper limit value and the second torque upper limit value can be set based on the same relationship, so that there is no need to store a separate relationship, and control can be simplified.
[0012]
The control method of the electric motor of the present invention,
A control method of a motor capable of outputting power to a drive shaft mounted on a vehicle and connected to drive wheels,
Detecting a current value applied to the electric motor,
Calculate the amount of change per unit time of the detected current value,
When the detected current value is less than a predetermined current value or the calculated change amount is less than a predetermined change amount, torque is output from the electric motor to the drive shaft based on a driver's operation and a running state of the vehicle. When the detected current value is equal to or more than a predetermined current value and the calculated change amount is equal to or more than a predetermined change amount, the motor is controlled based on the driver's operation and the running state of the vehicle. Drive control of the motor is performed such that torque output to the shaft is limited to a torque upper limit value set based on the detected current value or less and torque is output from the motor to the drive shaft.
That is the gist.
[0013]
According to the motor control method of the present invention, when the value of the current applied to the motor is equal to or greater than the predetermined current value and the amount of change in the current value per unit time is equal to or greater than the predetermined amount of change, the motor outputs to the drive shaft. Therefore, the erroneous determination based on noise and detection error is suppressed as compared with the determination based only on the current value applied to the electric motor, thereby preventing the excessive current from being more appropriately applied to the electric motor. be able to. Further, since the torque limitation is performed by the torque upper limit value set based on the current value applied to the electric motor, the idling is quickly performed by setting the torque upper limit value so that the idling quickly converges when the driving wheels are idling. Can be converged. Further, even if the torque is limited, if the torque based on the driver's operation and the running state of the vehicle is within the range of the torque limit, the torque is output from the electric motor to the drive shaft, so that the driver's intention is Can be reflected.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described using examples. FIG. 1 is a configuration diagram schematically showing the configuration of an electric vehicle 10 according to one embodiment of the present invention. As shown, the electric vehicle 10 according to the embodiment includes a motor 12 capable of outputting power to a drive shaft connected to drive wheels 18a and 18b using electric power supplied from a battery 16 via an inverter circuit 14. And an electronic control unit 40 for controlling the entire vehicle.
[0015]
The motor 12 is configured, for example, as a well-known synchronous generator motor that functions as a motor and also functions as a generator, and the inverter circuit 14 converts a plurality of power from the battery 16 into power suitable for driving the motor 12. It is composed of switching elements.
[0016]
The electronic control unit 40 is configured as a microprocessor having a CPU 42 as a center. In addition to the CPU 42, a ROM 44 storing a processing program, a RAM 46 temporarily storing data, an input / output port (not shown), Is provided. The electronic control unit 40 includes a motor current Im from a current sensor 15 attached to a power line from the inverter circuit 14 to the motor 12 and a rotation axis of the motor 12 detected by a rotation angle sensor 22 attached to the drive shaft. , The vehicle speed V of the electric vehicle 10 detected by the vehicle speed sensor 24, the wheel speeds Vf1, Vf2 of the drive wheels 18a, 18b detected by the wheel speed sensors 26a, 26b, 28a, 28b, and the driven wheels 19a, 19b. , The shift position from the shift position sensor 32 for detecting the position of the shift lever 31, and the accelerator opening from the accelerator pedal position sensor 34 for detecting the accelerator opening Acc in accordance with the amount of depression of the accelerator pedal 33. Acc, detects the amount of depression of the brake pedal 35 A brake depression amount from a brake pedal position sensor 36 is input through an input port that. The electronic control unit 40 outputs a switching control signal to a switching element of the inverter circuit 14 for controlling the driving of the motor 12 through an output port. Although the current detected by the current sensor 15 is the phase current of each phase of uvw of the motor 12, in the embodiment, for the sake of simplicity, the motor current Im is an effective value, that is, the discharge of the battery 16 It shall be treated as an agreement with the current.
[0017]
Next, an operation of the electric vehicle 10 of the embodiment configured as described above, particularly an operation when controlling the motor 12 so that the motor current Im does not become excessive will be described. FIG. 2 is a flowchart illustrating an example of a motor drive control routine executed by the electronic control unit 40 according to the embodiment. This routine is repeatedly executed every predetermined time (for example, every 8 msec).
[0018]
When the motor drive control routine is executed, the CPU 42 of the electronic control unit 40 first determines the accelerator opening degree Acc from the accelerator pedal position sensor 34, the vehicle speed V from the vehicle speed sensor 24, and the rotation angle θ of the rotation angle sensor 22. A process for inputting the motor rotation speed Nm calculated as described above, the motor current Im from the current sensor 15, and the like is executed (step S100). Here, in the embodiment, the vehicle speed V used is the one detected by the vehicle speed sensor 24, but is calculated from the wheel speeds Vf1, Vf2, Vr1, Vr2 detected by the wheel speed sensors 26a, 26b, 28a, 28b. It does not matter.
[0019]
Next, the required torque Tm * of the motor 12 is set based on the input accelerator opening Acc and vehicle speed V (step S102). In the embodiment, the setting of the motor required torque Tm * is determined in advance by obtaining the relationship between the accelerator opening Acc, the vehicle speed V, and the motor required torque Tm * and storing the relationship in the ROM 44 as a required torque setting map. Given the vehicle speed V, the corresponding motor required torque Tm * is derived from the map. FIG. 3 shows an example of the required torque setting map.
[0020]
When the required motor torque Tm * is set, a torque upper limit Tmax1, which is an upper limit of the torque output from the motor 12, is set based on the motor current Im read in step S100 (step S104), and the set torque upper limit Tmax1 is set. The motor required torque Tm * is limited so as to be as follows (steps S106 and S108). Here, the setting of the torque upper limit value Tmax1 is performed based on a torque upper limit value setting processing routine illustrated in FIG. When this routine is executed, first, a process of calculating a variation dI of the motor current Im is executed (step S130). In the embodiment, the change amount dI is calculated by subtracting the previous motor current Im input in the previous routine from the motor current Im input in this routine (current motor current Im-previous motor current Im). And This change amount dI can be considered in the same manner as the time change rate of the motor current Im, and the unit thereof is [A / 8 msec] because the execution time interval of this routine is 8 msec. Of course, any unit may be adopted as long as it can be expressed as a time change rate of the motor current Im. When the change amount dI is calculated in this way, the motor current Im is compared with the threshold value Iref (step S132), and the calculated change amount dI is compared with the threshold value dIref (step S134). Here, the threshold value Iref is set as the lower limit of the current value at which the torque limitation of the motor 12 is started, and a value smaller than the rated current of the motor 12, for example, a value of 80% thereof can be used. The threshold dIref is set as the lower limit of the amount of change in the motor current Im at which the torque of the motor 12 is started. For example, the threshold dIref is set to a value larger than the amount of change in the motor current Im that normally occurs when the vehicle is gripping. Can be used. If the motor current Im is less than the threshold value Iref or the variation dI is less than the threshold value dIref, it is determined that there is no need to limit the torque of the motor 12, and the rated torque of the motor 12 is set to the torque upper limit value Tmax1 (step S136). When this routine is completed and the motor current Im is equal to or greater than the threshold value Iref and the variation dI is equal to or greater than the threshold value dIref, it is determined that the torque of the motor 12 is required to be limited, and the torque upper limit value Tmax1 is set based on the motor current Im ( Step S138), this routine ends. In the embodiment, the torque upper limit value Tmax1 is set using a torque upper limit value setting map illustrated in FIG. In the example of FIG. 5, as the motor current Im increases, a smaller torque upper limit value Tmax is derived and set as the torque upper limit value Tmax1, and when the motor current Im reaches the rated current (rated maximum current) Imax of the motor 12, the torque increases. The upper limit value Tmax1 is set to a value 0. As a result, application of an excessive current to the motor 12 can be more reliably prevented. The torque upper limit setting map illustrated in FIG. 5 is also used for setting a torque upper limit Tmax2 based on the rotational angular acceleration α described later and a torque upper limit Tmax3 based on the torque limit δ1.
[0021]
Subsequently, the rotational angular acceleration α is calculated based on the motor rotational speed Nm input in step S100 (step S110), and the slip state of the drive wheels 18a and 18b is determined based on the calculated rotational angular acceleration α (step S112). ). The determination of the slip state is performed based on the slip state determination processing routine of FIG. When this slip state determination processing routine is executed, first, it is determined whether or not the rotational angular acceleration α calculated in step S110 of the routine in FIG. 2 exceeds a threshold αslip that can be regarded as causing slip due to idling. Is determined (step S140). When it is determined that the rotational angular acceleration α exceeds the threshold αslip, it is determined that a slip has occurred in the drive wheels 18a and 18b, and a slip occurrence flag F1 indicating the occurrence of the slip is set to a value of 1 (step S142), this routine ends. On the other hand, when it is determined that the rotational angular acceleration α does not exceed the threshold αslip, the value of the slip occurrence flag F1 is checked next (step S144). When the slip occurrence flag F1 has the value 1, it is determined whether the rotational angular acceleration α is a negative value and has continued for a predetermined time (step S146), and the rotational angular acceleration α is a negative value and If it is determined that this has continued for a predetermined time, it is determined that the slip generated on the drive wheels 18a and 18b has converged, and a value of 1 is set in the slip convergence flag F2 (step S148), and this routine is terminated. When it is determined that the slip occurrence flag F1 has the value 1 and the rotational angular acceleration α is not a negative value, or when it is determined that the rotational angular acceleration α has a negative value but does not continue for a predetermined time. Then, it is determined that the slip that has occurred has not yet converged, and the routine ends as it is.
[0022]
When the slip occurrence flag F1 and the slip convergence flag F2 are set by the slip state determination processing routine of FIG. 6, it is determined based on the slip occurrence flag F1 and the slip convergence flag F2 whether a slip has occurred or a slip has converged ( Step S114), processing according to the determination result (steps S116 and S118), that is, when it is determined that the slip occurrence flag F1 has the value 1 and the slip convergence flag F2 has the value 0, the slip occurrence processing is performed (step S114). (Step S116) When it is determined that both the slip occurrence flag F1 and the slip convergence flag F2 have a value of 1 and the slip has converged, a slip convergence process is performed (Step S118), and the final result is obtained. The motor 12 is driven so that the motor required torque Tm * is driven. 12 is controlled and driven (step S120), and terminates the motor drive control routine.
[0023]
The processing at the time of occurrence of slip in step S116 is performed by a control routine at the time of occurrence of slip illustrated in FIG. When this routine is executed, first, it is determined whether or not the rotational angular acceleration α exceeds the peak value αpeak (step S150). If it is determined that the rotational angular acceleration α exceeds the peak value αpeak, the peak is determined. A process for updating the value of the value αpeak to the rotational angular acceleration α is performed (step S152). Here, the peak value αpeak is basically the value of the rotational angular acceleration when the rotational angular acceleration α increases due to slip and shows a peak, and the value 0 is set as an initial value. Therefore, the peak value αpeak is sequentially updated to the value of the rotation angular acceleration α until the rotation angular acceleration α reaches the peak, and when the rotation angular acceleration α reaches the peak, the rotation angular acceleration α Is fixed as the peak value αpeak. When the peak value αpeak is set in this way, a process of setting a torque upper limit value Tmax2, which is the upper limit of the torque that the motor 12 can output, based on the peak value αpeak is performed (step S154). The setting of the torque upper limit value Tmax2 is performed using the torque upper limit value setting map illustrated in FIG. 5 used when setting the torque upper limit value Tmax1 based on the motor current Im described above. As shown in the map, the map has a characteristic that the torque upper limit value Tmax decreases as the peak value αpeak of the rotational angular acceleration increases. Accordingly, as the rotational angular acceleration α increases and the peak value αpeak increases, that is, as the degree of slip increases, a smaller value is set as the torque upper limit value Tmax2, and the torque output from the motor 12 is limited accordingly. become. When the torque upper limit Tmax2 is set, the motor required torque Tm * is limited by the set torque upper limit Tmax2 (steps S236 and S238), and this routine ends. By such processing, when the slip occurs, the torque output from the motor 12 is reduced to a low torque for suppressing the slip (specifically, the torque upper limit value Tmax corresponding to the peak value αpeak of the rotational angular acceleration in the map of FIG. 5). ), The slip can be effectively suppressed.
[0024]
The process at the time of slip convergence in step S118 is performed by a control routine at the time of slip convergence illustrated in FIG. When this routine is executed, first, a process of inputting the torque limit amount δ1 (the unit is [rpm / 8 msec] of the same unit as the rotational angular acceleration) is performed (step S160). Here, the torque limit amount δ1 is used to set a degree of return when the torque upper limit value Tmax set in correspondence with the peak value αpeak of the angular acceleration is raised in the slip occurrence control to return from the torque limit. These parameters are set based on the torque limit setting processing routine of FIG. This torque control amount setting processing routine is performed when the value 1 is set to the slip occurrence flag F1 in step S142 of the slip state determination processing routine illustrated in FIG. 6 (that is, when the rotational angular acceleration α exceeds the threshold αslip). Is executed. In this routine, the motor rotation speed Nm calculated based on the rotation angle θ detected by the rotation angle sensor 22 is input, the rotation angular acceleration α is calculated based on the input motor rotation speed Nm, and the rotation angular acceleration α Is repeated until the rotational angular acceleration α becomes less than the threshold αslip (steps S180 to S186). In the embodiment, the calculation of the time integral value αint of the rotational angular acceleration α is performed using the following equation (1). Here, Δt is an execution time interval for repeating steps S180 to S186 of this routine, and is 8 msec in the embodiment.
[0025]
(Equation 1)
αint ← αint + (α-αslip) · Δt (1)
[0026]
When the rotational angular acceleration α becomes smaller than the threshold value αslip, the calculated time integral value αint is multiplied by a predetermined coefficient k1 to set a torque limit amount δ1 (step S188), and the present routine ends. In this routine, the torque limit amount δ1 is obtained by calculation using a predetermined coefficient k1, but a map showing the relationship between the torque upper limit value Tmax and the time integral value αint is prepared, and the calculated time limit δ1 is calculated. It may be derived from the integral value αint by applying a map.
[0027]
Returning to the control routine at the time of slip convergence in FIG. 8, when the thus set torque limit amount δ1 is input, a release request for releasing the torque limit amount δ1 is input (step S162), and it is determined whether or not there is a release request. (Step S164). This process is a process of determining whether or not a request for canceling the torque limit amount δ1, which is a parameter used when setting the degree of return from torque limitation (gradually increasing the degree of return), has been input. In the present embodiment, a release request is input by a release amount Δδ1, which is set so as to increase from zero by a certain increment every time a predetermined standby period elapses after this routine is first executed. It was assumed. The standby period and the increase amount of the release amount Δδ1 may be changed according to the driver's own release request, for example, the magnitude of the accelerator opening indicating the torque output request desired by the driver. . If a release request is determined, the torque limit amount δ1 is released by subtracting the release amount Δδ1 from the torque limit amount δ1 input in step S160 (step S166). When it is determined that there is no cancellation request, that is, until the above-described predetermined standby period elapses after the execution of this routine is started, the torque limit amount δ1 is not canceled.
[0028]
Subsequently, a torque upper limit Tmax3, which is an upper limit of the torque that the motor 12 can output based on the torque limit δ1, is set using the above-described torque upper limit setting map of FIG. 5 (step S168), and the set torque upper limit is set. The motor required torque Tm * is limited by Tmax3 (steps S170, S172). Then, it is determined whether or not the torque limit δ1 has been released to a value equal to or less than 0 (step S174). If the torque limit δ1 has been released to a value equal to or less than 0, the slip occurrence flag F1 and the slip convergence flag F2 are reset to 0 (step S174). Step S176), this routine ends. As described above, controlling the torque of the motor 12 based on the torque limit amount δ1 set in accordance with the time integral value of the rotational angular acceleration α is performed when the generated slip is converged, depending on the situation of the generated slip. This is to restore an appropriate amount of torque in response. That is, in a situation where the time integral value of the rotational angular acceleration α is large and re-slip is likely to occur, the torque to be returned when the slip converges is reduced, and the time integral value of the rotational angular acceleration α is small and re-slip occurs. In a difficult situation, by increasing the torque to be returned when the slip has converged, it is possible to more reliably prevent the occurrence of re-slip without excessive torque limitation.
[0029]
Now, consider a case where slippage occurs due to idling of the drive wheels 18a and 18b. With respect to this slip, in the motor drive control routine of FIG. 2, the torque at the torque upper limit value Tmax2 is performed by the slip occurrence process in step S116, and the slip is suppressed. On the other hand, the idling of the drive wheels 18a and 18b appears as a sudden increase in the motor current Im applied to the motor 12, so that when the motor current Im becomes equal to or more than the threshold value Iref and the variation dI becomes equal to or more than the threshold value dIref, the torque upper limit value is increased. The torque of the motor 12 is also limited at Tmax1. At the time of such a slip, the torque limitation by the torque upper limit value Tmax1 and the torque limitation by the torque upper limit value Tmax2 are simultaneously performed. However, in the motor drive control routine of FIG. Thus, the torque is limited, so that the application of the excessive current of the motor 12 is prevented and the slip is suppressed at the same time. Although depending on the values of the threshold value Iref, the threshold value dIref, and the threshold value αslip, depending on which one of a phenomenon of a sudden increase in the motor current Im due to slip and a phenomenon of a change in the rotational angular acceleration α appears faster, It is determined whether the first torque limit is performed using the upper limit value.
[0030]
According to the electric vehicle 10 of the embodiment described above, the torque output from the motor 12 is limited based on the motor current Im and the amount of change dI so that an excessive current does not flow through the motor 12, so that the motor current Im Noise that can be mixed into the detection signal and erroneous determination due to erroneous detection can be suppressed as compared with the case where control is performed based on the above. That is, it is possible to more appropriately determine the possibility that an excessive current is applied to the motor 12 and suppress the application of the excessive current. In addition, since the torque of the motor 12 is limited by setting the torque upper limit Tmax1 so as to become smaller as the motor current Im becomes larger, it is possible to more reliably prevent an excessive current from being applied to the motor 12. Further, even under such torque limitation, the torque according to the driver's intention can be output from the motor 12 to the drive shaft within the range of the torque limitation.
[0031]
Further, according to the electric vehicle 10 of the embodiment, a torque upper limit value setting map used when setting the torque upper limit value Tmax1 based on the motor current Im to prevent an excessive current from being applied to the motor 12, A torque upper limit value setting map used to set the torque upper limit value Tmax2 based on the peak value αpeak of the rotational angular acceleration in order to suppress slip due to idling, and the torque of the motor 12 restricted for suppressing the slip is restored. In order to prevent an excessive torque from acting upon the setting, a torque upper limit value setting map used when setting the torque upper limit value Tmax3 based on the torque limit amount δ1 is shared. It can be simplified.
[0032]
Naturally, according to the electric vehicle 10 of the embodiment, the slip caused by the idling of the drive wheels 18a and 18b can be quickly and surely converged, and the re-slip immediately after the suppression of the slip can be more reliably suppressed. Further, even under the torque limitation in the control for suppressing such slip, the torque according to the driver's intention can be output from the motor 12 to the drive shaft within the range of the torque limitation.
[0033]
In the electric vehicle 10 of the embodiment, the setting of the torque upper limit value Tmax1 for preventing an excessive current from being applied to the motor 12, the setting of the torque upper limit value Tmax2 for suppressing slip due to idling, and the torque return of the motor 12 The torque upper limit setting map illustrated in FIG. 5 is commonly used for setting the torque upper limit Tmax3 at the time, but a different torque upper limit setting map may be used for setting each torque upper limit. No problem.
[0034]
In the electric vehicle 10 according to the embodiment, the drive control of the motor 12 is performed to prevent an excessive current from being applied to the motor 12, an excessive current prevention control for limiting a torque, and a slip due to idling of the drive wheels 18 a and 18 b is suppressed. Although the slip control is incorporated, the overcurrent prevention control may be incorporated, but the slip control may not be incorporated. Even in this case, as described above, the excessive current prevention control can be directly used as control for suppressing slippage of the drive wheels 18a and 18b due to idling, so that slippage of the drive wheels 18a and 18b due to idling can be suppressed.
[0035]
In the embodiment, the control of the motor 12 in the automobile 10 including the motor 12 mechanically connected to the drive shafts connected to the drive wheels 18a and 18b so that power can be directly output has been described. The invention may be applied to a vehicle having any configuration as long as the vehicle includes an electric motor capable of directly outputting power to an axle. For example, an engine, a generator connected to an output shaft of the engine, a battery for charging the generated power from the generator, and a supply of power from the battery mechanically connected to a drive shaft connected to drive wheels. The present invention may be applied to a so-called series-type hybrid vehicle including a driving motor. In this case, the motor does not need to be mounted on the drive shaft, but may be mounted on the axle, or may be mounted directly on the drive wheels like a so-called wheel-in motor. Further, as shown in FIG. 12, the engine 111, a planetary gear 117 connected to the engine 111, a motor 113 capable of generating electric power connected to the planetary gear 117, and also connected to the planetary gear 117 and to the driving wheels. The present invention can also be applied to a so-called mechanical distribution type hybrid vehicle 110 including a motor 112 mechanically connected to the drive shaft so that power can be directly output to the drive shaft. As shown in FIG. It has an inner rotor 213a connected to the output shaft and an outer rotor 213b attached to the drive shaft connected to the drive wheels 218a and 218b, and relatively rotates by the electromagnetic action of the inner rotor 213a and the outer rotor 213b. Motor 213 and a drive shaft capable of directly outputting power to the drive shaft. Can also be applied to a hybrid vehicle 210 of a so-called electric distribution type comprising a coupled to motor 212. Alternatively, as shown in FIG. 12, an engine 311 connected to a drive shaft connected to drive wheels 318a and 318b via a transmission 314 (such as a continuously variable transmission or a stepped automatic transmission), and an engine 311 And a motor 312 connected to the drive shaft via a transmission 314 (or a motor directly connected to the drive shaft). At this time, when slippage occurs in the drive wheels, the torque output to the drive shaft is limited by mainly controlling the motor mechanically connected to the drive shaft from the output response of the torque and the like. However, other motors or engines may be controlled in cooperation with the control of the motor.
[0036]
In the embodiment, a hybrid vehicle that prevents an excessive current of the motor 12 has been described.
[0037]
As described above, the embodiments of the present invention have been described using the examples. However, the present invention is not limited to these examples, and may be implemented in various forms without departing from the gist of the present invention. Obviously you can get it.
[Brief description of the drawings]
FIG. 1 is a configuration diagram schematically showing the configuration of an electric vehicle 10 according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating an example of a motor drive control routine executed by an electronic control unit 40 according to the embodiment.
FIG. 3 is an explanatory diagram showing an example of a required torque setting map.
FIG. 4 is a flowchart illustrating an example of a torque upper limit value setting routine;
FIG. 5 is an explanatory diagram showing an example of a torque upper limit value setting map.
FIG. 6 is a flowchart illustrating an example of a slip state determination processing routine.
FIG. 7 is a flowchart showing an example of a slip occurrence control routine.
FIG. 8 is a flowchart showing an example of a slip convergence control routine.
FIG. 9 is a flowchart illustrating an example of a torque limit amount setting processing routine;
FIG. 10 is a configuration diagram schematically showing a configuration of a hybrid type automobile 110.
FIG. 11 is a configuration diagram schematically showing a configuration of a hybrid type automobile 210.
FIG. 12 is a configuration diagram schematically showing a configuration of a hybrid type automobile 310.
[Explanation of symbols]
10, 110, 210, 310 electric vehicle, 12, 112, 212, 312 motor, 14, 114 inverter circuit, 15 current sensor, 16 battery, 18a, 18b, 118a, 118b, 218a, 218b, 318a, 318b driving wheel, 19a, 19b, 119a, 119b, 219a, 219b, 319a, 319b Follower wheels, 22 rotation angle sensors, 24 vehicle speed sensors, 26a, 26b, 28a, 28b Wheel speed sensors, 31 shift levers, 32 shift position sensors, 33 accelerator pedals , 34 accelerator position sensor, 35 brake pedal, 36 brake pedal position sensor, 40 electronic control unit, 42 CPU, 44 ROM, 46 RAM, 111, 211, 311 engine, 113 motor, 117 planetary gear , 213a inner rotor, 213b outer rotor, 213 motor, 314 transmission.

Claims (6)

An electric vehicle including an electric motor capable of outputting power to a drive shaft connected to drive wheels,
Drive control means for driving and controlling the motor so that torque is output from the motor to the drive shaft based on a driver's operation and a running state of the vehicle;
Current value detecting means for detecting a current value applied to the electric motor,
Change amount calculating means for calculating a change amount per unit time of the detected current value;
With
The drive control means, when the current value detected by the current value detection means is equal to or more than a predetermined current value and the change amount calculated by the change amount calculation means is equal to or more than a predetermined change amount, from the electric motor to the drive shaft An electric vehicle that is a means for limiting output torque. The drive control means sets a first torque upper limit value based on the detected current value, and limits the torque output from the electric motor to the drive shaft to be equal to or less than the set first torque upper limit value. The electric vehicle according to claim 1, wherein The electric vehicle according to claim 2, wherein the drive control unit is a unit that sets the first torque upper limit value in such a manner that the larger the detected current value is, the smaller the first torque upper limit value is. The electric vehicle according to claim 2 or 3,
Rotation angle acceleration detection means for detecting a rotation angle acceleration of the drive shaft,
Slip detecting means for detecting slip due to idling of the drive wheels based on the detected rotational angular acceleration,
With
When a slip is detected by the slip detecting means, the drive control means sets a second torque upper limit value based on the rotational angular velocity detected by the rotational angular acceleration detecting means, and sets the second torque upper limit value. An electric vehicle, which is means for restricting a torque output from the electric motor to the drive shaft so as to be less than or equal to a value. The drive control means is configured to determine a relationship between a current value and a torque upper limit used when setting the first torque upper limit and a relationship between a rotational angular acceleration and a torque upper limit used when setting the second torque upper limit. 5. The electric vehicle according to claim 4, wherein the first torque upper limit value and the second torque upper limit value are set using the same relationship as the same relationship. 6. A control method of a motor capable of outputting power to a drive shaft mounted on a vehicle and connected to drive wheels,
Detecting a current value applied to the electric motor,
Calculate the amount of change per unit time of the detected current value,
When the detected current value is less than a predetermined current value or the calculated change amount is less than a predetermined change amount, torque is output from the electric motor to the drive shaft based on a driver's operation and a running state of the vehicle. When the detected current value is equal to or more than a predetermined current value and the calculated change amount is equal to or more than a predetermined change amount, the motor is controlled based on the driver's operation and the running state of the vehicle. A motor for controlling the motor so as to limit the torque output to the shaft to be equal to or less than a torque upper limit value set based on the detected current value and to output the torque from the motor to the drive shaft. Control method.

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