JP3668553B2 - Electric vehicle control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an electric vehicle that determines drive / regenerative torque of a motor based on at least an accelerator opening, and controls the motor according to the determined drive / regenerative torque.
[0002]
[Prior art]
The response of the motor mounted on the electric vehicle to the opening and closing of the accelerator pedal is higher than the response of the internal combustion engine speed. For this reason, the vehicle body is affected by the reaction force that the motor receives when the accelerator pedal is depressed suddenly. There was a problem that the vibration was generated and the ride comfort was impaired. In particular, when the accelerator pedal is depressed and returned repeatedly at short time intervals, the shock when the backlash that exists in the power transmission system between the motor and the drive wheels disappears resonates with the natural frequency of the vehicle body, There has been a problem that vibrations that reduce ride comfort are likely to occur.
[0003]
Therefore, in the conventional electric vehicle, the occurrence of the vibration is prevented by delaying the rise of the motor torque when the accelerator pedal is stepped on rapidly.
[0004]
[Problems to be solved by the invention]
However, if the acceleration of the motor torque is delayed when the accelerator pedal is suddenly depressed as in the conventional case, the startup of the motor torque is delayed even when the driver requests rapid acceleration. There was a problem that acceleration performance deteriorated.
[0005]
The present invention has been made in view of the above circumstances, and an object thereof is to prevent the occurrence of the vibration while avoiding a decrease in the acceleration performance of the vehicle.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is an electric motor that determines a driving / regenerative torque of a motor based on at least an accelerator opening, and controls the motor according to the determined driving / regenerative torque. After detecting that the vehicle control device detects acceleration / deceleration detecting means for detecting acceleration / deceleration of the vehicle based on a change in the accelerator opening, and that the vehicle is switched from the acceleration state or the constant speed state to the deceleration state. And a torque increase limiting means for limiting an increase in the driving torque of the motor when acceleration of the vehicle is detected within the predetermined time.
[0007]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, the torque increase limiting means changes a time for limiting an increase in the driving torque of the motor in accordance with an accelerator opening during acceleration of the vehicle. It is characterized by doing.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.
[0009]
1 to 6 show an embodiment of the present invention. FIG. 1 is a diagram showing an overall configuration of an electric vehicle, FIG. 2 is a block diagram of a control system, and FIG. 3 is a block diagram showing a circuit configuration of an electronic control unit. FIG. 4, FIG. 4 is a flowchart for explaining the action, FIG. 5 is a time chart for explaining the action, and FIG. 6 is an explanatory view of a method for limiting the motor torque.
[0010]
As shown in FIGS. 1 and 2, the four-wheel electric vehicle V includes a pair of left and right front wheels Wf and Wf as drive wheels to which torque of the three-phase AC motor 1 is transmitted via a transmission 2, and driven wheels. Left and right rear wheels Wr, Wr. A main battery 3 of, for example, 288 volts mounted on the rear part of the electric vehicle V is connected to the motor 1 via the contactor 4, the joint box 5, the contactor 4, and the inverter 6 constituting the power drive unit. For example, the electronic control unit 10 connected to the sub-battery 7 of 12 volts via the main switch 8 and the fuse 9 is connected to the inverter 6 in order to control the driving torque and regenerative torque of the motor 1. A battery charger 11 and a DC / DC converter 12 are provided to charge the sub battery 7 with the power of the main battery 3.
[0011]
A high-voltage circuit connecting the main battery 3 and the inverter 6, that is, a DC sensor of the inverter 6 is provided with a current sensor S ₁ for detecting the current I _PDU and a voltage sensor S ₂ for detecting the voltage V _PDU. The current I _PDU of the DC part of the inverter 6 detected by the current sensor S ₁ and the voltage V _PDU of the DC part of the inverter 6 detected by the voltage sensor S ₂ are input to the electronic control unit 10. Further, the motor rotation speed Nm detected by the motor rotational speed sensor S _3, the accelerator opening theta _AP detected by the accelerator opening sensor S _4, the shift position P and an electronic control unit which is detected by the shift position sensor S ₅ 10 Is input.
[0012]
The inverter 6 includes a plurality of switching elements. By inputting a switching signal from the electronic control unit 10 to each switching element, the DC power of the main battery 3 is converted into three-phase AC power when the motor 1 is driven. The three-phase AC power generated by the motor 1 is converted into DC power and supplied to the main battery 3 when the motor 1 is driven (regeneration).
[0013]
The switching signal input from the electronic control unit 10 to the switching element of the inverter 6 is controlled by PWM (pulse width modulation). Further, field weakening control is performed after the duty ratio of PWM control reaches 100% in the high rotation region of the motor 1. In the field weakening control, the primary current supplied to the motor 1 has a field current component so that a field in the opposite direction to the field generated by the permanent magnet of the motor 1 is generated. The magnetism is weakened and the rotation speed of the motor 1 is extended to the high rotation speed side.
[0014]
Next, an outline of the circuit configuration and operation of the electronic control unit 10 will be described with reference to FIG.
[0015]
The electronic control unit 10 includes a torque command value calculation means 21, a target power calculation means 22, an actual power calculation means 23, a comparison means 24, a torque control means 25, an acceleration / deceleration detection means 28, and a torque increase restriction means 29. The comparison unit 24 and the torque control unit 25 constitute a feedback control unit 27.
[0016]
The torque command value calculation means 21 includes a motor rotation speed Nm detected by the motor rotation speed sensor S ₃ , an accelerator opening θ _AP detected by the accelerator opening sensor S ₄ , and a shift position P detected by the shift position sensor S _5. Based on the above, a torque command value that the driver is going to generate in the motor 1 is calculated by, for example, a map search. Acceleration / deceleration detection means 28 detects whether the or decelerating the vehicle is in the acceleration state based on a change in the accelerator opening theta _AP, torque increase limit unit 29 decelerates the acceleration / deceleration detection means 28 of the vehicle When the acceleration of the vehicle is detected within a predetermined time after detecting the above, a signal is output to the torque command value calculation means 21 to limit the rising of the torque command value of the motor 1.
[0017]
Target power calculating means 22, by multiplying the motor rotation speed Nm detected by the torque command value and the motor rotation speed sensor S ₃ calculated by the torque command value calculating unit 21, divides it in conversion efficiency, the motor 1 The target power to be supplied to the motor or to be taken out from the motor 1 by regeneration is calculated. The target power may be a positive value or a negative value. The positive target power corresponds to the case where the motor 1 generates driving torque, and the negative target power corresponds to the case where the motor 1 generates regenerative torque. To do.
[0018]
On the other hand, the actual power calculating means 23 multiplies the current I _PDU of the DC part of the inverter 6 detected by the current sensor S ₁ by the voltage V _PDU of the DC part of the inverter 6 detected by the voltage sensor S ₂ . The actual power input to the inverter 6 is calculated. Like the target power, the actual power can be either positive or negative. The positive actual power corresponds to the case where the motor 1 generates a driving torque, and the negative actual power is regenerated by the motor 1. This corresponds to the case where torque is generated.
[0019]
The target power calculated by the target power calculation means 22 and the actual power calculated by the actual power calculation means 23 are input to the comparison means 24 of the feedback control means 27, and based on the deviation between the target power calculated there and the actual power. The torque control means 25 controls the pulse width of the switching signal input to the inverter 6. As a result, the operation state of the motor 1 is feedback-controlled so that the actual power matches the target power.
[0020]
Next, the operation of the embodiment of the present invention will be described with reference to the flowchart of FIG.
[0021]
First, in step S1, the accelerator opening θ _AP detected by the accelerator opening sensor S ₄ is read, and in the subsequent step S2, the amount of change in the accelerator opening θ _AP per time, that is, the current value of the accelerator opening (θ _AP ) _N Then, the accelerator opening change amount Δθ _AP = (θ _AP ) _N − (θ _AP ) _N−1 is calculated by subtracting the previous value (θ _AP ) _N−1 from the value. As a result, if the accelerator opening change amount Δθ _AP is Δθ _AP <0 in step S3, that is, if the accelerator opening θ _AP is decreased and the vehicle is in a decelerating state, a torque increase restriction flag F described later in step S4. Is set to “1”, and a timer to be described later is cleared in step S5.
[0022]
In step S3, when the accelerator opening change amount Δθ _AP is not Δθ _AP <0 and the process proceeds to step S6, if the accelerator opening change amount Δθ _AP is held at Δθ _AP = 0, the process proceeds to step S7. Therefore, the first determination value T ₁ is set. Alternatively, if the accelerator opening change amount Δθ _AP is Δθ _AP > 0 in step S6 and the accelerator opening θ _AP at that time is less than the threshold θ _{REF in} step S8, the process proceeds to step S7 as well. Determination value T ₁ is reset. On the other hand, if the accelerator opening θ _AP at that time is greater than or equal to the threshold θ _REF in step S8, the process proceeds to step S8 and the second determination value T ₂ is set.
[0023]
The first determination value T ₁ and the second determination value T ₂ both define the time during which execution of torque increase limitation of the motor 1 is permitted, and the length of the first determination value T 1 is determined by the second determination value T ₂ . It is set to be shorter than T _1.
[0024]
Thus, when the vehicle shifts from the decelerating state to the accelerating state, the torque increase limiting flag F is already set to “1” in step S10 (see step S4). Therefore, the torque increase limiting control is executed in step S11. The As shown in FIG. 6A, when the vehicle is normally accelerated (acceleration not started within a predetermined time from the end of deceleration, but acceleration at the start of the vehicle, or acceleration started after a predetermined time has elapsed from the end of deceleration. ), The motor torque TRQ increases rapidly with a slight delay time as shown by the solid line, but when the torque increase restriction control is being executed, the motor torque TRQ gradually decreases with a relatively large delay time as shown by the broken line. To increase.
[0025]
In this torque increase limiting control, the timer currently counting is incremented in step S12, and the first determination value T ₁ or the second determination value T ₂ in which the count value of the timer is currently set in step S13 after a predetermined time has elapsed. Continue until over. When the count value of the timer exceeds the first determination value T ₁ or the second determination value T ₂ , the torque increase limit flag F is reset to “0” in step S14, and the torque increase limit control ends.
[0026]
Incidentally, when the first determination value T ₁ in step S7 to the accelerator opening change amount [Delta] [theta] _AP is a [Delta] [theta] _AP = 0 in step S6 is set, that is, when the vehicle is shifted from the deceleration state to the constant speed state In the first place, since the vehicle does not accelerate, the torque increase restriction control is not substantially executed in step S11. The count value of the timer if exceeds the first determination value T ₁ at step S13, it is torque increase limit control in step S14 is terminated. However, if the vehicle in the constant speed state shifts to the acceleration state in step S6, the first determination value T ₁ or the second determination value is determined depending on the magnitude relationship between the accelerator opening θ _AP and the threshold θ _{REF at} that time. T ₂ is newly set and torque increase restriction control is executed.
[0027]
In summary, when the vehicle deceleration state ends, the first determination value T ₁ having a relatively long time is set (step S7). If the vehicle shifts to an acceleration state with an accelerator opening θ _AP that is less than the threshold θ _REF before the count value of the timer exceeds the first determination value T ₁ (step S8), the first determination value T ₁ is reset ( Step S7), torque increase restriction control for delaying the increase speed of the motor torque TRQ is executed (step S11). This torque increase restriction control is continued until the count value of the timer exceeds the first determination value having a relatively long time (steps S13 and S14).
[0028]
Further, the count value of the timer transitions to the accelerating state the vehicle is at the threshold value theta _REF or more accelerator opening theta _AP before exceeding the first determination value T ₁ (step S8), and the second determination value T ₂ is newly set Then (step S9), torque increase restriction control for delaying the increase speed of the motor torque TRQ is executed (step S11). The torque increase limit control is continued until the count value of the timer exceeds the shorter second determination value T ₂ of the relatively time (step S13, S14).
[0029]
Furthermore, holding the constant speed state after the deceleration state of the vehicle is completed, when the count value of the timer has not shifted to the accelerating state to over first determination value T _1, the torque increase limit control is essentially Not executed.
[0030]
And Thus, when repeated at a time interval shorter than the first determination value T ₁ of the depression and a return of the accelerator pedal, the rate of increase of the motor torque TRQ during depression of the accelerator pedal is first determined value T ₁ or second determination Limited until value T ₂ elapses. As a result, the backlash existing in the power transmission system between the motor 1 and the drive wheels Wf and Wf expanded at the time of deceleration is prevented from suddenly disappearing at the time of acceleration and a shock is prevented, and the ride comfort is reduced due to the vibration of the vehicle body. Avoided.
[0031]
In addition, when there is no risk of a shock due to backlash existing in the power transmission system, that is, a time longer than the first determination value T ₁ has elapsed since the acceleration of the start of the vehicle or the end of the deceleration. At the time of subsequent acceleration, since the torque increase restriction control is not executed, the acceleration performance of the vehicle is not impaired. When the accelerator opening θ _AP during acceleration is equal to or greater than the threshold θ _REF and the driver is requesting rapid acceleration, the torque increase restriction control is executed only during the relatively short second judgment value T _2. Therefore, a decrease in the acceleration performance of the vehicle can be minimized.
[0032]
FIG. 5 is a time chart showing the operation when the accelerator opening degree θ _AP is increased or decreased stepwise. When the accelerator opening θ _AP decreases at time t ₁ , the motor torque TRQ decreases rapidly to the target torque with a normal slight delay time. At the same time, the torque increase limit flag F is set to “1” and the time is increased. A long first determination value T ₁ is set. If the accelerator opening θ _AP increases to a value less than the threshold θ _{REF at} time t ₂ before the first determination value T ₁ elapses, the first determination value T ₁ is reset, and at the same time, the torque TRQ increase limit control is performed. Is started, and the motor torque TRQ gradually increases with a delay time larger than usual. When the first determination value T ₁ elapses at time t ₃ , the torque increase restriction flag F is reset to “0”, and the torque increase restriction control ends. Note that when the accelerator opening θ _AP increases after the first determination value T ₁ has elapsed, the torque increase restriction control is not executed.
[0033]
Further, when the accelerator opening θ _AP decreases again at time t ₄ , the motor torque TRQ decreases rapidly to the target torque with a normal slight delay time, and at the same time, the torque increase limit flag F is set to “1”. Thus, the first determination value T ₁ is set. When the accelerator opening θ _AP increases to a value equal to or greater than the threshold θ _REF at time t ₅ before the first determination value T ₁ elapses, the second determination value T ₂ with a short time is set and at the same time, the torque increase limit When the control is started, the motor torque TRQ gradually increases with a delay time larger than usual. When the second determination value T ₂ elapses at time t ₆ , the torque increase limit flag F is reset to “0”, the torque increase limit control is terminated, and the motor torque TRQ reaches the target with a normal slight delay time. Increases quickly to torque. Also in this case, when the accelerator opening degree θ _AP increases after the first determination value T ₁ has elapsed, the torque increase restriction control is not executed.
[0034]
As mentioned above, although the Example of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.
[0035]
For example, in the embodiment, the torque increase restriction control is performed by changing the magnitude of the increase speed of the motor torque TRQ as shown in FIG. 6A. However, as shown in FIG. The torque increase restriction control may be performed by changing the time constant.
[0036]
【The invention's effect】
As described above, according to the first aspect of the present invention, the acceleration / deceleration of the vehicle is detected based on the change in the accelerator opening, and the vehicle is switched from the acceleration state or the constant speed state to the deceleration state. When the acceleration of the vehicle is detected within a predetermined time after the detection of the vehicle, the increase of the motor driving torque is limited, so when the accelerator pedal is depressed and returned repeatedly at short intervals, The backlash existing in the power transmission system from the motor is prevented from suddenly disappearing and a shock is prevented, and the ride comfort is improved. In addition, when there is no risk of shock due to backlash existing in the power transmission system, that is, during acceleration after starting the vehicle, torque during acceleration after the predetermined time has elapsed since the end of deceleration Since the increase restriction control is not executed, the acceleration performance of the vehicle is not impaired.
[0037]
According to the second aspect of the present invention, since the time for limiting the increase in the driving torque of the motor is changed according to the accelerator opening during the acceleration of the vehicle, the driving of the motor is performed when the driver's acceleration request is large. The acceleration performance can be ensured by shortening the time for limiting the increase in torque.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of an electric vehicle. FIG. 2 is a block diagram of a control system. FIG. 3 is a block diagram showing a circuit configuration of an electronic control unit. Time chart to explain 【FIG. 6】 Explanation of method to limit motor torque 【Explanation of symbols】
1 Motor 28 Acceleration / deceleration detection means 29 Torque increase limiting means θ _AP accelerator opening

Claims (2)

In the control device for an electric vehicle that determines the drive / regenerative torque of the motor (1) based on at least the accelerator opening (θ _AP ), and controls the motor (1) according to the determined drive / regenerative torque,
Acceleration / deceleration detection means (28) for detecting acceleration / deceleration of the vehicle based on a change in the accelerator opening (θ _AP );
Torque increase limit that limits the increase in driving torque of the motor (1) when acceleration of the vehicle is detected within a predetermined time after it is detected that the vehicle has switched from the acceleration state or the constant speed state to the deceleration state. Means (29);
An electric vehicle control apparatus comprising: The torque increase limiting means (29) changes a time for limiting an increase in driving torque of the motor (1) according to an accelerator opening (θ _AP ) during acceleration of the vehicle. The control apparatus of the electric vehicle as described.

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