JP3611390B2 - Control device for electric vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control apparatus for an electric vehicle comprising a plurality of systems of accelerator opening detecting means for detecting an accelerator opening, and an output command value calculating means for calculating an output command value of a motor based on the detected accelerator opening. About.
[0002]
[Prior art]
In general, an electric vehicle determines an output command value to be generated by the motor according to the accelerator opening and the motor rotation speed, and performs feedback control of the motor so that the output actually generated by the motor matches the output command value. ing. In order to prepare for the failure of the accelerator opening sensor that detects the accelerator opening, there is also known one provided with two accelerator opening sensors.
[0003]
[Problems to be solved by the invention]
By the way, if two accelerator opening sensors are provided, even if one accelerator opening sensor fails, the motor control can be continued based on the output of the other accelerator opening sensor. Before the opening sensor fails, it is necessary to repair the failed accelerator opening sensor.
[0004]
The present invention has been made in view of the above circumstances, and when one accelerator opening sensor of two systems fails, the driver is made to recognize the failure before the other accelerator opening sensor fails. The purpose is to encourage repairs.
[0005]
[Means for Solving the Problems]
In order to achieve the object, the invention described in claim 1 calculates a plurality of accelerator opening detecting means for detecting an accelerator opening, and calculates a motor output command value based on the detected accelerator opening. In the control apparatus for an electric vehicle including the output command value calculation means, when a failure detection means for detecting a failure of the accelerator opening detection means and a failure of any one of the accelerator opening detection means is detected, when a selection means for outputting the selected output command value calculating means accelerator opening detected by the accelerator opening detection means other strains, the failure of any one system accelerator opening detection means is detected, selected Output command value limiting means for limiting the output command value of the motor based on the accelerator opening selected by the means .
[0006]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, the output command value limiting means performs the limitation by performing a predetermined delay process on the output command value of the motor. .
[0007]
According to a third aspect of the present invention, in addition to the configuration of the first aspect, the operation of the output command value limiting means is prohibited when the direction in which the vehicle should travel and the direction in which the vehicle travels do not match. It is characterized by.
[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 8 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 first part of a flowchart of a torque command value calculation routine, FIG. 5 is a second part of a flowchart of a torque command value calculation routine, and FIG. 6 is a graph showing a change in accelerator opening at the time of failure. 7 is a flowchart of a torque command value limiting routine, and FIG. 8 is a graph showing changes in the torque command value at the time of failure.
[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 direct current portion 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,} first, second accelerator opening θ detected by the first accelerator opening sensor _{S 4-1} and the second accelerator opening sensor _{S 4-2 AP-1,} and θ _AP-2, a shift position P detected by the shift position sensor _{S 5} is inputted to the electronic control unit 10.
[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, and the motor 1, and when the motor 1 is driven (regeneration), the three-phase AC power generated by the motor 1 is converted into DC power and supplied to the main battery 3.
[0013]
Next, the circuit configuration and operation of the electronic control unit 10 will be described with reference to FIG.
[0014]
The electronic control unit 10 includes a torque command value calculation unit 21 (output command value calculation unit), a target power calculation unit 22, an actual power calculation unit 23, a comparison unit 24, a PWM control unit 25, a failure detection unit 26, a selection unit 27, and Torque command value limiting means 28 (output command value limiting means) is provided.
[0015]
The failure detection means 26 is based on the first and second accelerator openings θ _AP-1 and θ _AP-2 detected by the first accelerator opening sensor S _4-1 and the second accelerator opening sensor S _4-2. The failure of the first and second accelerator opening sensors S _4-1 and S _4-2 is detected. Based on the detection result of the failure detection means 26, the selection means 27 selects one of the first and second accelerator opening θ _AP-1 and θ _AP-2 as the accelerator opening θ _AP used for control.
[0016]
Torque command value calculating means 21, based on the motor rotation speed Nm detected by the motor rotational speed sensor S _3, the accelerator opening theta _AP was selected by the selecting means 27, a shift position P detected by the shift position sensor S ₅ Thus, the torque command value Q _TRQ that the driver is going to generate in the motor 1 is calculated based on a preset torque map.
[0017]
Torque command value limiting means 28, the detection result of the failure detection unit 26, the motor rotation speed Nm, based on the accelerator opening theta _AP, below the torque command value Q _TRQ torque command value calculating means 21 calculates Add certain restrictions.
[0018]
Target power calculating means 22, to be supplied to the motor 1 by multiplying the motor rotation speed Nm detected by the torque command value Q _TRQ and the motor rotational speed sensor S ₃ calculated by the torque command value calculating unit 21, or by regenerative A target power to be extracted from the motor 1 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.
[0019]
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.
[0020]
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, and the PWM control means 25 is based on the deviation between the target power calculated there and the actual power. The inverter 6 is PWM controlled. As a result, the operation state of the motor 1 is feedback-controlled so that the actual power matches the target power.
[0021]
Next, a failure determination routine executed mainly by the failure detection means 26 and the selection means 27 will be described with reference to the flowcharts shown in FIGS.
[0022]
First, with determining the failure of the first accelerator opening sensor _{S 4-1} and the second accelerator opening sensor _{S 4-2} in step S1 and step S2, the first, second accelerator opening sensor _{S 4} in step S3 _-1 and _S4-2 are determined.
[0023]
The first accelerator opening θ _AP-1 and the second accelerator opening θ _AP-2 detected by the first accelerator opening sensor _S4-1 and the second accelerator opening sensor _S4-2 are a predetermined upper limit value and It has a lower limit, and the first accelerator opening θ _AP-2 or the second accelerator opening θ _AP-2 , θ _AP-1 exceeds the upper limit due to a short circuit or the like or falls below the lower limit due to a disconnection or the like In this case, it is determined that the first accelerator opening sensor _S4-1 or the second accelerator opening sensor _S4-2 has failed. 6 (a) is shows an example of when the first accelerator opening sensor _{S 4-1} is determined to have failed at step S1, the first accelerator opening sensor _{S 4-1} at time _{t 1} Fails due to a short circuit or the like, and when the first accelerator opening θ _AP-1 exceeds the upper limit value, it is determined that a failure has occurred.
[0024]
If the first accelerator opening sensor _S4-1 and the second accelerator opening sensor _S4-2 are normal, the difference between the first accelerator opening θAP _-1 and the second accelerator opening θAP _-2 is Although it is a slight amount corresponding to an error, when the difference exceeds a predetermined value, it is determined that the first accelerator opening sensor _S4-1 or the second accelerator opening sensor _S4-2 has failed. FIG. 6B shows an example of a case where it is determined in step S3 that a differential failure has occurred. The first and second accelerator openings θ _AP-1 and θ _AP-2 at time t ₂ are shown. It is determined that a failure has occurred when the difference exceeds a predetermined value.
[0025]
Thus, if the occurrence of a failure is not determined in steps S1 to S3, the output restriction flag is set to “0” in step S4. When both the first accelerator opening sensor _S4-1 and the second accelerator opening sensor _S4-2 are normal, the first and second accelerator opening θAP _-1 and θAP _-2 are set. one value (e.g., smaller value) is selected as the accelerator opening theta _AP by the selection means 27.
[0026]
On the other hand, if in step S1 is the first accelerator opening sensor S _4-1 is determined to be faulty, the second accelerator opening theta _AP of the second accelerator opening sensor S _4-2 non-failing in step S5 _-2 is selected as the accelerator opening theta _AP. Also the second accelerator opening sensor _{S 4-2} is determined to have failed in step S2, the first accelerator opening theta _AP-1 of the first accelerator opening sensor _{S 4-1} non-failing in step S6 There is selected as the accelerator opening theta _AP. If it is determined in step S3 that a differential failure has occurred, the smaller value of the first and second accelerator openings θ _AP-1 and θ _AP-2 is selected as the accelerator opening θ _AP in step S7. .
[0027]
Thus, if any failure is determined in steps S1 to S3, an alarm lamp is turned on in step S8 to alert the driver.
[0028]
In the following step S9, the rotation direction of the selected motor 1 (“D” range is forward, “R” range is reverse) and the actual rotation direction of the motor 1 are compared. If the vehicle slides backward when trying to move forward on an uphill, or if the vehicle slides forward when trying to move backward on a downhill, the process proceeds to step S4 and the output restriction flag is set to “ Set to “0”.
[0029]
In step S10, S11 followed, the current and previous values of the selected accelerator opening theta _AP, compared respectively with a predetermined value. And either the current value of the accelerator opening theta _AP is less than the predetermined value in step S10, or the previous accelerator opening theta _AP current value of the accelerator opening theta _AP is in the step S11 even more than a predetermined value in step S10 If the value is equal to or greater than the predetermined value, the process proceeds to step S4, and the output restriction flag is set to “0”.
[0030]
In the following step S12, the motor rotation speed Nm is compared with a predetermined value. If the motor rotation speed Nm is equal to or greater than the predetermined value, the process proceeds to step S4 and the output restriction flag is set to “0”. The process proceeds to step S13. If the previous value of the output restriction flag is not “1” in step S13, that is, if the previous value of the output restriction flag is “0”, the process proceeds to step S14 and the output restriction flag is set to “1”. In step S15, the torque command value Q _TRQ at that time is set as an initial value of the output restriction control of the motor 1.
[0031]
To summarize what is meant by the steps S9 to S12, when the failure in the first accelerator opening sensor S _4-1 or the second accelerator opening sensor S _4-2 occurs, sliding down occurs in slope If the accelerator pedal is large and is depressed quickly and the motor speed Nm is low, the output restriction flag is set to “1”. As a result, on the premise that there is no possibility that the vehicle will slide down on the slope, the output limitation control of the motor 1 is performed when the driver has a strong intention to accelerate and the motor 1 generates a large torque at a low speed. Is executed.
[0032]
And Thus, in step S16, and updates the previous value in the newly selected current value of the accelerator opening theta _AP in this loop.
[0033]
Next, a torque command value limiting routine executed mainly in the torque command value limiting means 28 will be described with reference to the flowchart shown in FIG.
[0034]
First, in step S21~ step S23, the torque command value calculating unit 21 reads the motor rotation speed Nm, the accelerator opening theta _AP and shift position P, and calculated based on the torque map a torque command value _{Q TRQ} in step S24. If the output restriction flag is set to “1” in the subsequent step S25, the process _proceeds to step S26, where the first delay process is performed on the torque command value Q _TRQ to limit the output of the motor 1. That is, as shown in FIG. 8A, when the output restriction flag is set to “1” at time t ₃ , the torque command value Q _TRQ is changed from the initial value to the current torque command value Q _TRQ (torque map value). ) Increase gradually without increasing rapidly.
[0035]
As a result, even if the driver depresses the accelerator pedal suddenly, the expected acceleration cannot be obtained, and this indicates that some failure has occurred in the first and second accelerator opening sensors S _4-1 and S _4-2. The driver can recognize it and prompt repair. Even if the motor output is limited as described above, the torque command value Q _TRQ eventually increases to the torque map value with a time delay, so that there is no problem in traveling to a repair shop, for example. Furthermore, even if both the first and second accelerator opening sensors S _4-1 and S _4-2 fail, it is possible to avoid the torque command value Q _TRQ from increasing rapidly.
[0036]
Instead of limiting the torque command value Q _TRQ by the first-order lag process, as shown in FIG. 8B, the torque command value Q _TRQ is increased from the initial value to a torque map value by a predetermined value for each loop. The same effect can be obtained.
[0037]
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.
[0038]
For example, in the embodiment, the motor output is limited by limiting the torque command value Q _TRQ , but the motor opening degree θ _AP output by the selection means 27 and the duty ratio of the PWM control means 25 are limited. It is also possible to limit the output. Further, when the motor output is limited, the output may be limited so that the output is steadily smaller than the target value by a certain ratio or by a certain amount. Further, the number of accelerator opening sensors _S4-1 and _S4-2 is not limited to two, and may be three or more.
[0039]
【The invention's effect】
As described above, according to the first aspect of the present invention, when a failure of the accelerator opening detecting means of any one system is detected, the accelerator opening detected by the accelerator opening detecting means of another system is detected. Is selected to control the motor and limit the motor output, so that even if one of the accelerator opening detection means fails, the motor control can be continued and the motor output is limited. Then, the repair can be urged by notifying the driver of the occurrence of the failure.
[0040]
According to the second aspect of the present invention, since the output of the motor is limited by applying a predetermined delay process to the output command value of the motor, the motor output is gradually increased to the output command value and the vehicle travels. It is possible to secure output enough to continue.
[0041]
According to the third aspect of the present invention, since the operation of the output command value limiting means is prohibited when the direction in which the vehicle should travel and the direction in which the vehicle actually travels do not match, the vehicle slides down when starting on a slope. When this happens, the output of the motor can be quickly increased to prevent the sliding.
[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. Fig. 5 is a second part of the flowchart of the torque command value calculation routine. Fig. 6 is a graph showing changes in the accelerator opening at the time of failure. Fig. 7 is a flowchart of the torque command value limiting routine. Graph showing changes in torque command value [Explanation of symbols]
1 Motor 21 Torque command value calculation means (output command value calculation means)
26 Failure detection means 27 Selection means 28 Torque command value limiting means (output command value limiting means)
Q _TRQ torque command value (output command value)
S _4-1 First accelerator opening sensor (accelerator opening detecting means)
S _4-2 Second accelerator opening sensor (accelerator opening detecting means)
θ _AP-1 first accelerator opening (accelerator opening)
θ _AP-2 Second accelerator opening (accelerator opening)

Claims (3)

Accelerator opening _{(θ AP-1, θ AP} -2) an accelerator opening detection means of a plurality of systems for detecting the (S _4-1, S _4-2) and the accelerator opening (θ _AP-1 was detected, theta _AP-2 ) In an electric vehicle control device comprising an output command value calculating means (21) for calculating an output command value (Q _TRQ ) of the motor (1) based on
Accelerator opening detection means (S _4-1, S _4-2) a failure detecting means (26) for detecting a failure of any one system accelerator opening detection means (S _4-1, S _4-2) When a malfunction is detected, select and output the accelerator opening (θ _AP-1 , θ _AP-2 ) detected by the accelerator opening detection means (S _4-1 , S _4-2 ) of another system Selecting means (27) for outputting to the command value calculating means (21);
The output of the motor (1) based on the accelerator opening selected by the selecting means (27) when a failure of the accelerator opening detecting means ( _S4-1 , _S4-2 ) of any one system is detected. Output command value limiting means (28) for limiting the command value (Q _TRQ );
An electric vehicle control apparatus comprising: The control of an electric vehicle according to claim 1, wherein the output command value limiting means (28) performs the limitation by applying a predetermined delay process to the output command value (Q _TRQ ) of the motor (1). apparatus. 2. The control device for an electric vehicle according to claim 1, wherein the operation of the output command value limiting means (28) is prohibited when the direction in which the vehicle should travel and the direction in which the vehicle actually travels do not match.

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