JPH07193903A - Controller for electric vehicle - Google Patents

Abstract

PURPOSE:To obtain a controller for electric vehicle in which the running feeling is prevented from deteriorating due to abnormal voltage drop of a main battery by limiting the current even if accelerator operation is increased when the inner resistance of the main battery increases thereby preventing abrupt malfunction or hunting of the vehicle. CONSTITUTION:The controller for electric vehicle comprises a controller 5A for an inverter 2 to generate a desired power torque To from an induction motor 1 using the output voltage alpha from an accelerator position sensor 4 as a variable, means 6 for detecting the voltage Vb of a main battery 3, means 7 for setting a voltage reference Vr higher than the lowest operating voltage of the inverter controller, and an auxiliary control means 9 for controlling the inverter to limit the power torque from the induction motor when the voltage of main battery drops below the voltage reference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle controller for controlling the voltage and frequency of an inverter in response to the output of an accelerator position sensor to control the power running torque of an induction motor, and particularly when the voltage of a main battery drops. The present invention relates to an electric vehicle control device capable of preventing abnormal reduction in main battery voltage and maintaining smooth running by suppressing the power running torque of an induction motor.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing a conventional electric vehicle control device using an inverter and an induction motor, and schematically shows a power running drive control system. In the figure, reference numeral 1 indicates a power running torque To for driving a vehicle 3
The phase induction motor 2 is an inverter that serves as a main circuit for controlling the voltage and frequency applied to the induction motor 1, and the reference numeral 3 is a main battery that supplies electric power energy to the induction motor 1 and the inverter 2.

Reference numeral 4 denotes an accelerator position sensor (hereinafter referred to as APS) which detects the position α of the accelerator operated by the driver's intention with a voltage signal. Reference numeral 5 denotes an inverter control device that controls the induction motor 1 via the inverter 2 in accordance with the detection signal α (accelerator opening) of the APS 4, and uses the output voltage value of the APS 4 as a variable.
So as to generate a desired power running torque To.
The M signal controls the current and frequency for the inverter 2.

The APS 4 is composed of, for example, a potentiometer and generates a voltage according to the accelerator opening. Further, the inverter control device 5 follows the function characteristic of FIG. 8 so as to be substantially proportional to the output voltage value α [V] of the APS 4 corresponding to the accelerator opening degree.
Control [N · m].

Generally, the applied voltage and frequency to the induction motor 1 controlled by the inverter control device 5 via the inverter 2 are controlled so that the ratio of the applied voltage and the drive frequency is substantially constant. Further, the driving performance of the vehicle is required to have a characteristic as shown in FIG. 9, and the power running torque To is controlled to be constant at a rotational speed No [rpm] or less of the induction motor 1 based on the rated value, and a high-speed rotation region of the rated No or higher. Then, the constant output control is performed and the power running torque To is gradually reduced.

Therefore, in order to obtain the power running torque characteristics as shown in FIG. 9 over a wide range of rotation speeds N from 0 to the maximum rotation speed, the inverter control device 5 requires the exciting current and load torque supplied to the induction motor 1. Is calculated as a vector, and the power running torque To output from the induction motor 1 is made to coincide with the command torque in all operating zones. The control technique of the induction motor 1 based on such a vector control method has been introduced in recent years and has already been put into practical use, and is a widely known technique. Therefore, detailed description of the operation is omitted.

By the way, in the control of the induction motor 1 by the inverter 2, the power running torque To which is substantially proportional to the accelerator operation amount α is output from the induction motor 1 and the main battery 3
Supplies the necessary electric power for driving the induction motor 1 regardless of the remaining amount of the main battery 3 itself. Therefore, when the remaining amount of the main battery 3 is small, or when the characteristics of the main battery 3 are deteriorated, the internal resistance of the main battery 3 is high,
When the induction motor 1 is required to have a high output due to the accelerator operation, the main battery 3 may cause an excessive voltage drop.

In the case of an electric vehicle, it is necessary to drive at least to the place where the charging equipment is located when the end of discharge of the main battery 3 is detected. The voltage Vb of the battery 3 may fall below the minimum operating voltage Vo of the inverter control device 5, and the vehicle may suddenly be disabled. Further, as a result of the inability to drive the vehicle, the supply current Ib of the main battery 3 decreases, the voltage Vb of the main battery 3 rises, and the vehicle is driven again. Further, the voltage Vb of the main battery 3 increases. Occurs again and the hunting phenomenon occurs that the driving of the vehicle becomes impossible,
It becomes impossible to obtain a good running and acceleration feeling.

[0009]

As described above, the conventional electric vehicle control device supplies the electric power necessary for driving the induction motor 1 from the main battery 3 regardless of the remaining amount. When a high output power running torque To is required for the induction motor 1 in a state where the internal resistance of the main battery 3 is high such as when the remaining amount of the battery 3 is small or when the characteristics are deteriorated, the main battery 3 is An excessive voltage drop is caused to fall below the minimum operating voltage Vo of the control device 5, the driving of the vehicle is suddenly disabled, and a hunting phenomenon of the vehicle driving is generated.
There is a problem that it is not possible to travel smoothly to a place with a charging facility.

The present invention has been made in order to solve the above problems, and suppresses the power running torque of the induction motor when the voltage of the main battery drops, thereby improving the driving feeling due to an abnormal drop in the voltage of the main battery. An object is to obtain an electric vehicle control device that prevents deterioration.

[0011]

An electric vehicle control apparatus according to claim 1 of the present invention comprises an induction motor for driving a vehicle,
An inverter that controls the applied voltage and frequency to the induction motor, a main battery that supplies energy to the induction motor and the inverter, an APS that detects the position of an accelerator operated by the driver, and an output voltage value of the APS as variables. An inverter control device that controls the inverter so as to generate a desired power running torque from the induction motor, a voltage detection means that detects the voltage of the main battery, and a reference voltage setting that sets a reference voltage that is equal to or higher than the minimum operating voltage of the inverter control device. Means, and inverter auxiliary control means for controlling the inverter so as to suppress the power running torque of the induction motor when the voltage of the main battery becomes lower than the reference voltage.

According to a second aspect of the present invention, in the electric vehicle control system according to the first aspect, the inverter auxiliary control means gradually reduces the power running torque of the induction motor at regular time intervals.

According to a third aspect of the present invention, in the electric vehicle control system according to the first aspect, the inverter auxiliary control means provides the power running torque of the induction motor corresponding to the deviation between the voltage of the main battery and the reference voltage. It suppresses.

According to a fourth aspect of the present invention, there is provided an electric vehicle control device according to the first, second or third aspect, which includes a display for notifying a driver of the state of the vehicle.
The display drive means for driving the display in response to the control state of the inverter auxiliary control means is provided, and the display is in a state immediately before the power running torque of the induction motor is suppressed, and the power running torque of the induction motor is currently suppressed. It informs that it is in the middle or that the voltage of the main battery is in an abnormally low state.

[0015]

According to the first aspect of the present invention, even if the voltage of the main battery detected by the voltage detecting means is lowered, the power running of the induction motor is prevented so that the voltage of the main battery does not become lower than the minimum operating voltage of the inverter control device. Suppress torque.

Further, according to the second aspect of the present invention, the power running torque of the induction motor is gradually reduced at a constant time interval.

According to the third aspect of the present invention, the power running torque of the induction motor is suppressed corresponding to the deviation between the voltage of the main battery and the reference voltage.

Further, according to claim 4 of the present invention, the power running torque suppression state or the abnormal voltage reduction state of the main battery is displayed to inform the driver of the abnormal state, and a prompt countermeasure against the voltage decrease of the main battery is taken. to enable.

[0019]

【Example】

Example 1. A first embodiment of the present invention (corresponding to claim 1 and claim 4) will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of Embodiment 1 of the present invention.
To 4 are the same as described above. Further, 5A corresponds to the inverter control device 5. In this case, the inverter control device 5A has a voltage monitoring function of the main battery 3 and a power running torque suppressing function of the electric motor 1, as described later.

6 is a voltage detecting means for detecting the voltage Vb of the main battery 3, and 7 is the minimum operating voltage V of the inverter control unit 5A.
Reference voltage setting means for setting a reference voltage Vr equal to or higher than o, 8
Is an arithmetic means including a comparator for comparing the magnitude of the reference voltage Vr with the voltage Vb of the main battery 3.

Reference numeral 9 is an inverter auxiliary control means added in the inverter control device 5A, and in response to the operation output signal C from the operation means 8, the voltage Vb of the main battery 3 becomes lower than the reference voltage Vr. In this case, the inverter 2 is controlled so as to suppress the power running torque To of the induction motor 1.

Reference numeral 10 is an indicator for notifying the driver of the vehicle control status by the inverter auxiliary control means 9, and 11 is an indicator 1 in response to the control state of the inverter auxiliary control means 9.
It is a display driving means for driving 0. The display device 10 is under the control of the display device driving means 11 that the power running torque To of the induction motor 1 is in a state immediately before being suppressed, that the power running torque To of the induction motor 1 is currently being suppressed, or the main battery. It is notified that the voltage Vb of 3 is in an abnormally lowered state.

FIG. 2 is a characteristic diagram showing the relationship between the discharge current Ib of the main battery 3 and the voltage Vb. The solid line is the characteristic curve when the main battery 3 is fully charged, and the broken line is the characteristic curve at the end of discharge of the main battery 3. is there. As is clear from FIG. 2, when the driver performs excessive accelerator operation, especially when the internal resistance of the main battery 3 is large in the final discharge state or deterioration state,
The voltage Vb of the main battery 3 decreases as the discharge current Ib increases (see the broken line).

Next, the operation of the first embodiment of the present invention will be described with reference to the flowchart of FIG. First, the voltage detector 6 detects the voltage Vb of the main battery 3 (step S1), and the calculator 8 calculates the main battery voltage Vb.
b and the reference voltage Vr are compared to determine whether the main battery voltage Vb is equal to or lower than the reference voltage Vr (step S
2).

If it is determined that the main battery voltage Vb is higher than the reference voltage Vr (that is, NO), the routine returns, and if it is determined that the main battery voltage Vb is equal to or lower than the reference voltage Vr (that is, YES), The calculation means 8 generates a calculation output signal C indicating an abnormality with respect to the inverter auxiliary control device 9 in the inverter control device 5A.

The inverter auxiliary control device 9 responds to the operation output signal C indicating the abnormal voltage drop and responds to the indicator driving means 1
A state in which the display 10 is driven via 1 to display an abnormal decrease in the voltage Vb of the main battery 3 as a warning and the power running torque To output from the induction motor 1 is to be suppressed (state immediately before suppression). Is displayed in advance (step S3).

Subsequently, the voltage Vb of the main battery 3 is changed to the reference voltage V
In order to avoid the state of r or less, the power running torque To of the induction motor 1 is suppressed (step S4). That is, the inverter auxiliary control means 9 detects the voltage Vb of the main battery 3 by the voltage detection means 6 at every predetermined timing when the electric vehicle is running, and the main battery voltage Vb is the reference voltage Vr.
When the following occurs, the display 10 warns the driver of the abnormal voltage drop of the main battery 3 and the induction motor 1
After notifying that the power running torque To of 1 is suppressed, the power running torque To of the induction motor 1 is suppressed. In addition, display 1
0 indicates that the power running torque To is under the suppression control.

By the above power running torque suppression control, the power running torque To of the induction motor 1 is reduced and the current Ib of the main battery 3 is reduced.
Therefore, the voltage Vb of the main battery 3 can always be controlled to be equal to or higher than the reference voltage Vr. Therefore, it is possible to prevent the vehicle from suddenly stopping due to the decrease of the main battery voltage Vb, and to control the voltage Vb of the main battery 3 to the inverter control device 5A
Can be controlled to the minimum operating voltage Vo or higher.

Further, by maximizing the remaining capacity of the main battery 3, the traveling distance can be maximized. Further, since the abnormal state is displayed by the display device 10, while traveling with a smooth and good feeling to the place where the charging equipment is located while the power running torque To is suppressed,
The driver can quickly take measures to avoid the abnormality.

Example 2. In the first embodiment, the power running torque suppression step S4 was not specifically described, but in reality, when the main battery voltage Vb becomes equal to or lower than the reference voltage Vr, a large amount of power running torque suppression is performed at once. Since there is a problem that a shock will occur, it is desirable to gradually suppress it.

FIG. 4 is a flow chart showing the operation of the second embodiment (corresponding to claim 2) of the present invention for suppressing the power running torque so that the vehicle shock does not occur, S2 is the same step as described above, and S41 And S42 correspond to the power running torque suppressing step S4.

In this case, when it is determined in step S2 that the main battery voltage Vb is equal to or lower than the reference voltage Vr, a predetermined torque amount ΔT from the current power running torque To which causes no shock to the vehicle is stepped at predetermined timings. Subtraction (step S41), and the predetermined timing is returned via the timer (step S42) for setting. In this way, by gradually reducing the power running torque To at every predetermined timing, it is possible to avoid a shock due to a sudden change in the vehicle running state.

Example 3. In the second embodiment, the power running torque To is reduced by the predetermined torque amount ΔT at every predetermined timing, but the suppression rate of the power running torque To may be changed according to the deviation ΔV between the main battery voltage Vb and the reference voltage Vr. Good. FIG. 5 is a flowchart showing a third embodiment (corresponding to claim 3) of the present invention in which the power running torque suppression coefficient is determined according to the deviation ΔV between the main battery voltage Vb and the reference voltage Vr.

In this case, the calculating means 8 includes a voltage deviation calculating means for calculating a deviation ΔV between the reference voltage Vr and the detected main battery voltage Vb, and the calculating means 8 calculates the deviation ΔV from the reference voltage Vr to the main battery voltage Vb.
To obtain the voltage deviation ΔV (step S4
3), output to the inverter auxiliary control means 9.

Further, the inverter auxiliary control means 9 includes a suppression coefficient calculation means for calculating a suppression coefficient K corresponding to the voltage deviation ΔV, and the suppression coefficient K (0 <K
<1) is calculated (step S44), and a value obtained by multiplying the current power running torque To by the suppression coefficient K is set as the suppressed power running torque To '(step S45).

FIG. 6 shows the suppression coefficient K in step S44.
It is a characteristic diagram used to determine the voltage deviation Δ
The suppression coefficient K also increases in accordance with the increase of V, and after reaching K = 1, it becomes constant at K = 1 regardless of the increase of the voltage deviation ΔV. In the third embodiment of the present invention, when the voltage deviation ΔV is small, the power running torque To is suppressed to the necessary minimum to minimize the shock, and when the voltage deviation ΔV is large, the power running torque To is quickly suppressed. can do.

In the above-described second or third embodiment as well, similar to the first embodiment, the sudden stop of the vehicle due to the decrease of the main battery voltage Vb is prevented and the voltage Vb of the main battery 3 is reduced.
Can be controlled to be equal to or higher than the minimum operating voltage Vo of the inverter control device 5A. It is needless to say that the same effect can be obtained by adding the display device 10 as in the first embodiment.

[0038]

As described above, according to claim 1 of the present invention, an induction motor for driving a vehicle, an inverter for controlling a voltage and a frequency applied to the induction motor, and an induction motor and a main for supplying energy to the inverter. APS that detects the position of the battery and the accelerator operated by the driver
And an inverter control device for controlling the inverter so as to generate a desired power running torque from the induction motor using the output voltage value of the APS as a variable, a voltage detection means for detecting the voltage of the main battery, and a minimum operation of the inverter control device. A reference voltage setting means for setting a reference voltage equal to or higher than the voltage, and an inverter auxiliary control means for controlling the inverter so as to suppress the power running torque of the induction motor when the voltage of the main battery becomes lower than the reference voltage, Since the power running torque of the induction motor is suppressed when the main battery voltage drops, the current is suppressed even if the accelerator operation amount increases when the internal resistance of the main battery increases, and sudden vehicle incapability or hunting may occur. In addition, there is an effect that an electric vehicle control device can be obtained in which the driving feeling is prevented from deteriorating due to an abnormal decrease in the main battery voltage.

According to a second aspect of the present invention, in the first aspect, the inverter auxiliary control means gradually reduces the power running torque of the induction motor at regular time intervals. There is an effect that it is possible to obtain an electric vehicle control device that more reliably prevents the deterioration of the driving feeling due to an abnormal reduction.

According to a third aspect of the present invention, in the electric vehicle control system according to the first aspect, the inverter auxiliary control means provides the power running torque of the induction motor corresponding to the deviation between the voltage of the main battery and the reference voltage. Since the control is promptly performed, there is an effect that an electric vehicle control device can be obtained in which the deterioration of the driving feeling due to the abnormal decrease of the main battery voltage is more surely prevented.

According to a fourth aspect of the present invention, there is provided an electric vehicle control device according to any one of the first, second or third aspects, which includes a display for notifying a driver of the state of the vehicle.
The display drive means for driving the display in response to the control state of the inverter auxiliary control means is provided, and the display is in a state immediately before the power running torque of the induction motor is suppressed, and the power running torque of the induction motor is currently suppressed. Since it is notified that it is in the middle or that the voltage of the main battery is abnormally low, deterioration of the driving feeling due to abnormally low voltage of the main battery is prevented, and promptly for abnormal conditions. There is an effect that an electric vehicle control device that can deal with the problem can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing the reference voltage in Example 1 of the present invention together with the voltage of the main battery.

FIG. 3 is a flowchart showing the operation of the first embodiment of the present invention.

FIG. 4 is a flowchart showing a power running torque suppressing operation according to the second embodiment of the present invention.

FIG. 5 is a flowchart showing a power running torque suppressing operation according to a third embodiment of the present invention.

FIG. 6 is a characteristic diagram showing a relationship between a voltage deviation for determining a suppression coefficient and the suppression coefficient according to the third embodiment of the present invention.

FIG. 7 is a block diagram showing a conventional electric vehicle control device.

FIG. 8 is a characteristic diagram showing a relationship between an accelerator position and a power running torque in a general electric vehicle control device.

FIG. 9 is a characteristic diagram showing a relationship between a rotation speed and a power running torque in a general electric vehicle control device.

[Explanation of symbols]

 1 Induction Motor 2 Inverter 3 Main Battery 4 Accelerator Position Sensor 5A Inverter Control Device 6 Voltage Detection Means 7 Reference Voltage Setting Means 8 Computing Means 9 Inverter Auxiliary Control Means 10 Display 11 Display Means α Accelerator Position To Power Torque Vb Main Battery Voltage Vo Minimum operating voltage Vr Reference voltage ΔV Voltage deviation

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[Procedure amendment]

[Submission date] March 24, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

By the above power running torque suppression control, the power running torque To of the induction motor 1 is reduced and the current Ib of the main battery 3 is reduced.
Therefore, the voltage Vb of the main battery 3 can always be controlled to be equal to or higher than the reference voltage Vr. Therefore, it is possible to prevent the vehicle from running suddenly due to a decrease in the main battery voltage Vb, and to control the voltage Vb of the main battery 3 to be equal to or higher than the minimum operating voltage Vo of the inverter control device 5A.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

In the above-described second or third embodiment, as in the first embodiment, it is possible to prevent the vehicle from suddenly being unable to run due to a decrease in the main battery voltage Vb, and to control the voltage Vb of the main battery 3 by an inverter control device. It can be controlled to a minimum operating voltage Vo of 5 A or higher. Further, as in the first embodiment,
It goes without saying that the addition of the display 10 produces the same effect.

Claims (4)

[Claims] 1. An induction motor for driving a vehicle, an inverter for controlling a voltage and a frequency applied to the induction motor, a main battery for supplying energy to the induction motor and the inverter, and an accelerator operated by a driver. An electric vehicle control device including an accelerator position sensor that detects a position, and an inverter control device that controls the inverter so as to generate a desired power running torque from the induction motor by using an output voltage value of the accelerator position sensor as a variable. In the voltage detection means for detecting the voltage of the main battery, the reference voltage setting means for setting a reference voltage higher than the minimum operating voltage of the inverter control device, the voltage of the main battery is lower than the reference voltage The inverter so as to suppress the power running torque of the induction motor. Electric vehicle control apparatus is characterized by providing an inverter auxiliary control means Gosuru. 2. The electric vehicle control device according to claim 1, wherein the inverter auxiliary control means gradually reduces the power running torque of the induction motor at regular time intervals. 3. The electric vehicle control device according to claim 1, wherein the inverter auxiliary control means suppresses the power running torque of the induction motor in accordance with a deviation between the voltage of the main battery and the reference voltage. . 4. A display device for notifying a driver of the state of the vehicle, and a display drive device for driving the display device in response to a control state of the inverter auxiliary control device are provided. A notification that the power running torque of the induction motor is in a state immediately before being suppressed, that the power running torque of the induction motor is currently being suppressed, or that the voltage of the main battery is in an abnormally low state. The electric vehicle control device according to claim 1, claim 2, or claim 3.