JP2002262402A - Control device for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an electric vehicle capable of suppressing battery consumption, even if a state that the operation amount of an accelerator is large continues for long hours when a motor is in stalling. SOLUTION: The control device for an electric vehicle is provided with a battery, the motor driven by the battery, and a control means for controlling the motor. The control device is also provided with a stall-state detection means for the motor, and an in-stall current upper-limit setting means that sets the value of a current flowing to the motor to an in-stall current upper-limit value based on an output signal of the stall-state detection means, and further provided with a final-current indication value calculation means that reduces the power consumption of the battery by suppressing the value of the current flowing to the motor, when the stalling is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electric vehicle, and more particularly, to a control device for an electric vehicle configured to reduce waste of a battery when an electric motor is stalled.

[0002]

2. Description of the Related Art Generally, electric vehicles such as electric vehicles and forklifts are driven by controlling electric power from a battery and rotating an electric motor based on a signal from an electric vehicle control device. In order to obtain the same operational feeling as an automobile equipped with a normal internal combustion engine, the conventional electric vehicle control device controls the electric current flowing through the electric motor so that the generated torque changes according to the increase or decrease of the accelerator operation amount. A control mechanism that performs control to increase or decrease the speed and thereby accelerates / decelerates is used.

[0003] Here, when a so-called stall state occurs, in which a current flows through a motor without flowing, the temperature of the motor or the like rises and causes a failure. Therefore, the stall prevention or the stall state is prevented. An electric vehicle control device technology for reducing electric power to an electric motor in response to detection to prevent damage due to a rise in temperature of a field effect transistor (FET) included in the electric motor and a drive circuit, or to correct a defect in a stall prevention operation. Have been proposed (for example, JP-A-5-168285, JP-A-7-
336807, JP-A-8-51793, JP-A-9-201087, JP-A-2000-2642
No. 32).

As another prior art, since the electric vehicle is based on the electric power of the battery, the consumption of the battery is a particular problem. To solve this problem, acceleration by depressing the accelerator at the time of transmission is required. There has been proposed a technology of an electric vehicle control device that allows a driver to feel the arrival of a recharge time of a battery by reducing performance (for example, see Japanese Patent Application Laid-Open No. 9-191506).

[0005]

By the way, the market needs for the electric vehicle include stall prevention, cost reduction and compactness of the system, prolongation of one charge traveling distance of the battery, and stall occurrence. In some cases, the maximum output time can be extended.

Here, for example, when the electric vehicle is stopped, such as when the electric vehicle is in a groove or the like, the driver is instructing the electric vehicle to drive. Battery is wasted. That is, in the case where the motor is in the stall state, if the state where the accelerator operation amount is large is continued for a long time, a large current continues for a long time in the motor even though the vehicle does not run. Because it flows.

That is, in the normal state, the inventor sets the value of the current flowing through the electric motor based on the accelerator operation amount and the state of the vehicle, and corrects the set value to a value equal to or less than the maximum current limit value. If the stall state of the electric motor is detected and the accelerator operation amount is equal to or more than a predetermined value, the maximum current limit value is reduced at least once. That is, when the state where the accelerator operation amount is large in the stall state of the electric motor is continued for a long time, it is necessary to temporarily suppress the current value flowing through the electric motor to prevent waste of the battery. Has gained insights.

[0008] However, the prior art is aimed at preventing stalls or failures of electric motors and the like, and in all cases, special consideration is given to reducing the power consumption of the battery. Absent. The present invention has been made in view of such a problem, and an object of the present invention is to suppress battery waste even when a state in which the accelerator operation amount is large in an stalled state continues for a long time. It is an object of the present invention to provide a control device for an electric vehicle that can perform the control.

[0009]

In order to achieve the above object,
An electric vehicle control device of the present invention is basically an electric vehicle control device including a battery, an electric motor driven by the battery, and a unit for controlling the electric motor,
The control device includes: a stall state detection unit for the electric motor;
A stall current upper limit value setting unit that sets a current value flowing through the electric motor to a stall current upper limit value based on an output signal of the stall state detection unit,
When detecting a stall, a final current command value calculating means for suppressing the current value flowing through the electric motor to reduce the power consumption of the battery is provided.

[0010] In the electric vehicle control device according to the present invention configured as described above, when the stall state detecting means detects that the motor is in the stall state, the current upper limit value setting means at the time of the stall is connected to the electric motor. Since the power consumption of the battery is reduced by suppressing the flowing current value, for example, even when the motor is stalled and the accelerator operation amount is large, the amount of current flowing out of the battery is limited to an arbitrary value or less. The battery consumption can be suppressed, and the extension of one charge traveling distance of the electric vehicle, the extension of the continuation time of the maximum output during stall, and the like can be realized.

In a specific aspect of the control device for an electric vehicle according to the present invention, the stall state detecting means includes: a rotation speed of the electric motor, a rotation direction of the electric motor, a current value flowing through the electric motor, and an accelerator detection amount. Detecting the stall state based on the above, or the stall current upper limit value setting means, the temperature of the motor or the temperature of the element provided in the means for controlling the motor, and the output signal from the stall state detection means The upper limit value is set based on the following formula, or the current upper limit value setting means at the time of the stall sets the upper limit value to be equal to or less than the continuous rated current value of the electric motor.

Further, in another specific embodiment of the electric vehicle control device according to the present invention, the electric motor is an AC motor, and the means for controlling the electric motor is an inverter.
When the temperature of the switching element in the inverter becomes equal to or higher than a predetermined value in the stall state, the current upper limit value setting means may set the current upper limit value to be reduced at least once, or The current upper limit setting means sets the current upper limit to be reduced when the temperature of the switching element is equal to or higher than a predetermined value, and sets the current when the temperature of the switching element is equal to or lower than the predetermined value. The upper limit value is set to be raised, or the current upper limit value setting means at the time of the stall is set to reduce the current upper value at least once when the temperature of the electric motor becomes a certain value or more in the stall state. Or the current upper limit value setting means at the time of the stall, when the temperature of the electric motor becomes a certain value or more. Is set to lower the current upper limit value, and if the temperature of the electric motor becomes equal to or lower than a certain value, the current upper limit value is set to be raised, or the current upper limit value setting means at the time of stall is a stall state. If the stall state continues for a certain period of time, the current upper limit value is set to be reduced at least once, or the stall current upper limit value setting unit lowers the current upper limit value when the stall state continues for a certain period of time. Make the settings,
Thereafter, the current upper limit value is set to be raised at regular intervals.

Still further, in still another specific embodiment of the electric vehicle control device according to the present invention, the stall state detecting means is configured so that the rotation speed of the electric motor is 0 and a current value flowing through the electric motor is positive. , And when the state of the maximum value of the accelerator detection amount has continued for a certain time or more,
Detecting that the motor is in the stall state, or detecting the stall state when the rotation of the motor is in the reverse direction in response to the rotation direction command from the means for controlling the motor. Or the stall state detecting means prohibits the detection of the stall state when the state in which the maximum value of the accelerator detection amount continues in the inclined state for a predetermined time or more. .

Further, the electric vehicle control device generates a warning sound from the electric motor according to the setting of raising and lowering the upper limit value by the current upper limit value setting means at the time of stall, and the driver is in a stall state. Or the electric vehicle is an electric vehicle, or the electric vehicle is a forklift.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an electric vehicle control device according to the present invention will be described in detail with reference to the drawings. Figure 1
1 is a circuit configuration diagram of an electric vehicle having an electric control device 7 of the present embodiment. The circuit includes a battery 1, a key switch 3 for starting the system, an input circuit 3a for inputting the state of the key switch 3 to the electric control device (microcomputer) 7, a fuse 4, and a drive for the inverter 12. A contactor 5 for opening and closing the power supply, a drive circuit 5a for the contactor 5, a constant voltage circuit 6 for a power supply of a microcomputer 7, a microcomputer 7, an accelerator 8, and an operation amount of the accelerator 8
An input circuit 8a for inputting a signal to the microcomputer 7; a forward / backward switch 9 for issuing a command for the rotation direction of the induction motor 15;
a, an inverter 12 for driving an induction motor 15, and a MOS-FE as a switching element in the inverter 12
T10, a temperature sensor 11 for detecting the temperature of the MOS-FET 10, an input circuit 11a for inputting a signal from the temperature sensor 11 to the microcomputer 7, a current sensor 13 for detecting a field current of the induction motor 15, Sensor 13
Circuit 13 for inputting a signal from the microcomputer to the microcomputer 7
a, a temperature sensor 14 for detecting the temperature of the induction motor 15,
An input circuit 14 a for inputting a signal from the temperature sensor 14 to the microcomputer 7, a three-phase AC induction motor 15, a resolver 16 as a rotation angle detector connected to the induction motor 15, and a signal from the resolver 16. It comprises an input circuit 16a for inputting to the microcomputer 7.

FIG. 2 is a block diagram showing a processing content configuration of the microcomputer 7 which is the electric control device. Note that the microcomputer 7 executes the initial processing only once immediately after startup, and defines the initial state and the like of the microcomputer 7, but the block diagram of FIG. 2 shows the state after the initial processing of the microcomputer 7 is completed.

The microcomputer 7 includes an input processing means 20, a current command calculation means 21, a stall detection processing means 22,
The key switch 3 and its input circuit 3a are composed of a current upper limit value setting means 23 at the time of stall, another current upper limit value setting means 24, a final command value calculating means 25, and a drive signal transmitting means 26 for the inverter 12. The operation is performed while the signal KEY is turned on to control the electric motor 15.

The input processing means 20 includes an accelerator input circuit 8
a, the forward / reverse direction command FR from the front / rear switch input circuit 9a, MOS-F
MOS-FET1 from ET temperature sensor input circuit 11a
0 temperature TTMP, induction motor temperature sensor input circuit 14
a from the motor 15 and the field current signal C of the motor 15 from the induction motor current sensor input circuit 13a.
D is input. At this time, the resolver input circuit 1
The rotation angle ANGLE from the motor 15a is also input, but this rotation angle ANGLE is differentiated and the rotation speed S
Treated as PD.

The stall detection processing means 22 calculates the accelerator operation amount ACC and the rotation speed SPD of the electric motor 15.
And a forward / backward direction command FR and a field current signal CD of the electric motor 15 to set a flag STOOL to be described later,
It outputs to the current upper limit value setting means 23 at the time of stall.

The current upper limit value setting means 23 at the time of stall is
The flag STOOL and the temperature TTM of the MOS-FET 10
The first maximum current limit value STLMT is calculated based on P or the temperature MTMP of the electric motor 15 and is output to the final command value calculation means 25. In addition, the current upper limit value setting means 23 at the time of stall is set to a value having a small current capacity of a switching element or the like at the time of stall, separately from a current value which enters the machine in response to a general current control command, as described later. This is set as a limit value at the time of stall to prevent the battery 1 from being wasted.

On the other hand, the current command calculating means 21 calculates an ideal current command value IMT from the accelerator operation amount ACC and the rotational speed SPD of the electric motor 15 and outputs the calculated current command value IMT to the final command value calculating means 25. Other current upper limit setting means 24
Is the nth current limit value L when the current value needs to be limited due to various other factors other than the stall.
MTn is calculated, and this is also output to the final command value calculating means 25. Here, n indicates that there may be a plurality of such limit values.

The final command value calculating means 25 calculates a current command value IMT which is an ideal value obtained by the current command calculating means 21.
And a first current limit value SLMMT by the current upper limit value setting means 23 during stall and an n-th current limit value LMTn by the other current upper limit value setting means 24. IMT2 is calculated and output to the drive signal transmitting means 26 for the inverter 12, and the drive signal transmitting means 26 transmits a drive signal for the inverter 12 so that the final current command value IMT2 flows to the electric motor 15. This drive signal is output from the MOS-FE in the inverter 12.
Applied to T10, the electric motor 15 is driven.

[0023] FIG. 3 is an operational flowchart of the microcomputer 7, wherein an electric control device. First, when the key switch 3 is turned on, the constant voltage circuit 6 operates, and power is supplied to the microcomputer 7 to start it. In step 101, initial processing is executed by the input processing means 20, processing such as initialization of the microcomputer 7 is performed, a signal is sent to the drive circuit 5 a to close the contactor 5, power is supplied to the inverter 12, and power is supplied to the inverter 12. Proceed to.

In step 102, input processing is executed by the input processing means 20, and a key switch detection value KEY obtained through the key switch input circuit 3a, a field current signal CD obtained through the current sensor input circuit 13a, and
An accelerator detection value ACC obtained through an accelerator input circuit 8a, a forward / backward traveling direction command FR obtained through a forward / reverse switch input circuit 9a, and an induction motor 15 obtained through an input circuit 16a of a resolver 16 as a rotation detector.
And the process proceeds to step 103. At this time, the rotation speed SPD is obtained by differentiating the rotation angle ANGLE.

Also in step 103, input processing is executed by the input processing means 20, and the motor temperature sensor input circuit 14
a, the temperature MTMP of the motor 15 obtained through
The temperature TTMP of the MOS-FET 10 obtained through the S-FET temperature sensor input circuit 11a is fetched, and the process proceeds to step 104.

In step 104, a stall detection process is executed by the stall detection processing means 22, as will be described later, and if the motor 15 is in a stall state, the flag S
TOOL = 1, otherwise the flag STOOL
= 0 and the routine proceeds to step 105.

In step 105, the stall current upper limit value setting means 23 calculates a first maximum current limit value STLMT as a limit value for the field current when the motor 15 is in a stall state as described later. , Step 1
Proceed to 06. In step 106, the other current upper limit setting unit 24 sets the n-th current limit LMT as described later.
n is set, and the routine proceeds to step 107.

In step 107, the final command value calculating means 25 will be described later based on signals from the current command calculating means 21, the current upper limit value setting means 23 during stall, and other current upper limit value setting means. To the final current command value I
MT2 is set, and the routine proceeds to step 108. Step 10
At 8, the drive signal is output to the inverter 12 by the drive signal transmitting means 26 to the inverter 12 so that the field current signal CD flows in accordance with the current command value IMT2, and the routine proceeds to step 109.

In step 109, the key switch 3
Is determined to be in the ON state. If the key switch 3 is ON, that is, if YES, the steps 102 to 108 are repeatedly executed. On the other hand, when the key switch 3 is not turned on, the microcomputer 7 is stopped and a series of operations is ended.

FIG. 4 is an operation flowchart of stall detection by the stall detection processing means 22. In step 104 (FIG. 3) of the stall detection processing means 22, as a stall detection process, first, a reverse rotation detection process, which will be described later, is executed in step 201. If the motor 15 is rotating in the reverse direction, the flag INV = 1 is set. INV is the case not
= 0 and the routine proceeds to step 202.

In step 202, the accelerator operation amount AC
C, the accelerator operation amount ACC is equal to a predetermined value ACMA.
It is determined whether or not X is equal to or greater than X. If accelerator operation amount ACC is equal to or greater than predetermined value ACMAX, the process proceeds to step 203; otherwise, the process proceeds to step 209 and SL is performed.
Set OPE = 0. Here, the predetermined value ACMAX is:
For example, the maximum operation amount of the accelerator 8 is set.

In step 203, it is determined whether or not the flag SLOPE = 0 with reference to the flag SLOPE (initial value is 0) indicating the slope of the slope. If there is, go to step 204;
Proceed to. In step 204, referring to the rotation speed SPD,
It is determined whether or not the rotation speed SPD = 0, and the rotation speed SPD
Proceeds to step 212 when a PD = 0, if not speed SPD = 0, the process proceeds to step 205.

In step 205, it is determined whether or not the rotation direction is positive with reference to the direction INV of the rotation speed SPD. If the rotation direction is positive, that is, if INV = 0, the process proceeds to step 207, Direction is negative, ie INV = 1
If it is, the process proceeds to step 208. In step 212, it is determined whether or not the field current signal CD> 0 with reference to the field current signal CD.
If it is, go to step 206; otherwise, go to step 207.

In step 206, the accelerator operation amount ACC is equal to or more than the predetermined value ACMAX, and there is no inclination due to the slope, that is, the flag SLOPE = 0, and the rotation speed SPD.
= 0 and the field current signal CD> 0, so that the process proceeds to step 210 with the slope flag SLOPE = 0 and the stall condition is detected as the flag STOOL = 1, which is the stall condition. 10
Proceed to 5 (FIG. 3).

In step 207, the accelerator operation amount AC
C is equal to or greater than a predetermined value ACMAX and the flag SLOPE = 0, but the rotation speed SPD is not 0 and the direction is positive INV =
Since the flag is 0, the flag SLOPE is set to 0 and step 21 is executed.
Proceed to 1. Further, the accelerator operation amount ACC is equal to a predetermined value ACM.
AX or more, flag SLOPE = 0, rotation speed SPD = 0
However, since the field current signal is not CD> 0, the flag SLOPE = 0 is set and the process proceeds to step 211. further,
Also in step 209, the accelerator operation amount ACC is
Since it is less than or equal to CMAX, the flag SLOPE = 0 is set and the process proceeds to step 211.

In step 208, the accelerator operation amount AC
Although C is equal to or greater than the predetermined value ACMAX, SLOPE is not 0, and the slope is present. Therefore, the flag SLOPE is set to 1 so as not to suppress the output, and the process proceeds to step 211. The accelerator operation amount ACC is equal to or greater than a predetermined value ACMAX and the flag SLOPE = 0, but the rotation speed SPD =
Since the rotation direction is negative INV = 1 instead of 0, the flag SLOPE = 1 is set and the process proceeds to step 211.

In step 211, it is detected that the vehicle is not in a stall state, the flag STOOL = 0 is set, the operation in step 104 is terminated, and the routine proceeds to step 105 (FIG. 3). Incidentally, in the branch step 204 of FIG.
If the electric motor 15 is not completely stalled, or if the motor 15 is slightly rotated due to backlash of the machine or the like, the condition of the branch step 204 may be set to | SPD | <SPDL, and this SPDL is, for example, equivalent to 10 cm / sec. Value.

Also, | SPD | <SPDL and | SP using the rotation angle ANGLE of the electric motor 15
If the displacement of the rotation angle after D | <SPDL is within a minute range, steps 206 and 210
May be executed, and if not, step 205 may be executed. In this case, when the vehicle is slowly retreating on a slope or the like, the amount of displacement of the rotation angle continues to increase, so that it is possible to more accurately detect that the vehicle is climbing a slope. Further, when the magnitude of the current value during the stall is known in the branching step 212, the field current signal CD ≧ CDST may be satisfied. Here, CDST is a current value flowing at the time of stall.

FIG. 5 is an operation flowchart of the reverse rotation detection by the stall detection processing means 22. In step 201 (FIG. 4) of the stall detection processing means 22, first, in step 301, the forward / rearward traveling direction command FR
, It is determined whether or not FR = F (rotation in the forward direction). If FR = F, the process proceeds to step 303; otherwise, the process proceeds to step 302. Also in step 302, referring to the forward / backward traveling direction command FR, FR =
R (rotation in the reverse direction), FR = R
If it is, go to step 304; otherwise, go to step 308.

In step 304, it is determined whether or not the rotation speed SPD is positive by referring to the rotation speed SPD. If the rotation speed SPD is positive, the process proceeds to step 306.
Otherwise, go to step 307. Also in step 303, it is determined whether or not the rotation speed SPD is positive. If the rotation speed SPD is positive, step 3
Go to step 05, otherwise go to step 306.

Then, in step 305, FR = F,
The rotation speed SPD is positive, and in step 307, FR
= R, the rotational speed SPD is positive, and in step 308, since FR is not equal to R, the reverse rotation detection flag INV = 0
And the operation of step 201 is terminated.
Proceed to (FIG. 4).

On the other hand, in step 306, although FR = F, the rotation speed SPD is not positive, the reverse rotation detection flag INV = 1 is set, and since FR = R and the rotation speed SPD is positive, reverse rotation detection is performed. When the flag INV is set to 1, the operation of Step 201 ends, and the process proceeds to Step 202 (FIG. 4).

FIG. 6 is an operation flowchart for setting the first maximum current limit value STLMT by the current upper limit value setting means 23 during stall. In step 105 (FIG. 3) of the current upper limit value setting means 23 at the time of stall, as the setting of the first maximum current limit value STLMT, it is first determined in step 401 whether or not the flag STOOL indicating a stall state is 1 or not. If the flag STOOL = 1, that is, if YES, the process proceeds to step 402, where the first maximum current limit value STLMT is set to the continuous rated current ISTD or less as described later, and the operation of step 105 is terminated. To step 106 (FIG. 3).

On the other hand, if the flag STOOL is not 1, the routine proceeds to step 403, and since the state is a normal state, the first maximum current limit value STLMT is set to a predetermined value IMLM.
AX is set, the operation of step 105 is completed, and the process proceeds to step 106 (FIG. 3). Here, the predetermined value IMAX
Is, for example, the smaller of the maximum current values that can be passed through the motor 15 or the MOS-FET 10. Alternatively, the value may be smaller than this.

FIG. 7 is a timing chart for setting the first maximum current limit value STLMT by the current upper limit value setting means 23 during stall. The value of the first maximum current limit value STLMT as a limit value for the field current when the electric motor 15 is in the stall state in step 402 (FIG. 6) is set as shown in the following time-series graph.

In the figure, the upper graph (1) shows the time change of the accelerator operation amount ACC. The accelerator operation amount ACC is depressed to ACMAX at a certain time t1, and the depression is relaxed at t2. It is shown that. The next graph (2) shows that at the time point t1, the stall determination condition is satisfied and the flag STOOL = 1.
This indicates that the stall condition is no longer satisfied at the time point t2 and the flag STOOL = 0.

Then, of the following two lower graphs,
Graph (3) shows the temperature MTMP (or MO
A graph (4) shows a time change of the temperature TTMP of the S-FET 10 with respect to the time change with respect to the set value of the first maximum current limit value STLMT.

In a normal state, the first maximum current limit value SLTMT = IMAX as described above,
The flag STOOL = 1 indicating the stall state, and the accelerator operation amount ACC reaches ACMAX t
At time points 3, 3, t5 and t7, the temperature MTMP of the electric motor 15 ≧ the predetermined value MTMAX (or the MOS-FET 10
TTMP ≧ predetermined value TTMAX), the first maximum current limit value STLMT is changed to the predetermined value ISTD.
The value is reduced to the following value (for example, 90% of ISTD). Here, the predetermined value ISTD is, for example, the smaller one of the continuous rated currents of the motor 15 and the MOS-FET 10 and the predetermined value MTMAX.
Is, for example, 90% of the heat resistance of the electric motor 15, and the predetermined value TTMAX is, for example, the heat resistance of the MOS-FET 10.
90%.

On the other hand, at each time point of t4 and t6, the temperature MTMP of the motor 15 ≦ the predetermined value MTSTD (or MO
Since the temperature of the S-FET 10 is TTMP ≦ the predetermined value TTSTD), the first maximum current limit value STLMT is changed from the predetermined value ISTD to the first maximum current limit value STLMT.
= Pull up again to IMAX and set. Here, the predetermined value MTSTD is, for example, a steady temperature when a continuous rated current is applied to the electric motor 15, and the predetermined value TTSTD is:
For example the steady state temperature when a current of rated continuous current in MOS-FET 10.

As described above, in the case of the stall state, the maximum output state IMAX and the limited state ISTD are repeated within the range of the heat resistance of the motor 15 and the MOS-FET 10 and flow through the motor 15. current value can be reduced power consumption of the battery 1 is suppressed, the electric vehicle can be kept even longer a state where the maximum output is put out even immediately after emerged from the stall state.

Further, by repeating the maximum output state IMAX and the limited state ISTD, the current is greatly pulsated and a warning sound is generated from the electric motor 15, so that the driver is notified that the vehicle is in a stall state in which the vehicle cannot escape. You can also. Note that, as the limited state, the first maximum current limit value STLMT may be reduced to 0, and also in this case, the motor 15 generates a loud warning sound,
The driver can be notified of the stall condition.

The trigger for changing the value of the first maximum current limit value STLMT is not the temperature change of the electric motor 15 or the like as described above, but, for example, the first maximum current limit 3 minutes after the stall state. The value of the limit value STLMT may be set as a certain time, such as decreasing the value, increasing the value every minute thereafter, and repeatedly decreasing the value.

FIG. 8 shows the setting of another limit value LMTn by another current upper limit value setting means 24. In this limit process, for example, the motor 15 or the MOS-FET 1
There is a limiting process for the purpose of 0 temperature protection. As shown in the figure, when the temperature of the motor 15 is MTMP ≦ MTMAX (or the temperature of the MOS-FET 10 is TTMP ≦ TTMA).
If X, the other limit value LMTn is set to the predetermined value IMAX, and step 106 (FIG. 1) is performed. If the temperature MTMP of the electric motor 15 is greater than MTMAX (or the temperature TTMP of the MOS-FET 10). > TTMAX), the other limit value LMTn is set to the predetermined value ISTD.
This means that step 106 (FIG. 1) is performed by setting the following value (for example, a value corresponding to 50% of ISTD).

FIG. 9 is an operational flowchart for setting the final current limit value IMT2 by the final command value calculating means 25. In step 501, the minimum value among the first maximum current limit value SLTMT to the n-th maximum current limit value LMTn is set to the minimum value among the final maximum current limit value processing 1 to n setting values. The final current limit value LMT is set, and the process proceeds to step 502. In step 502, it is determined whether or not IMT> LMT by referring to the current command value IMT calculated by the current command calculating means 21.
If it is MT, the process proceeds to step 503; otherwise, the process proceeds to step 504.

In step 503, since IMT> LMT and the current command value IMT is larger, the final current command value IMT2 = final current limit value LMT
Step 107 (FIG. 3) ends. On the other hand, in step 504, since the current command value IMT is smaller, the step 107 (FIG. 3) ends with the final current command value being IMT2 = the current command value IMT calculated by the current command calculation means 21. . As described above, the embodiment of the present invention has the following functions by the above configuration.

That is, in the electric vehicle control device 7 of the present embodiment, the stall state detection processing means 22 of the electric motor 15
When the stall state is detected, the current value flowing through the motor 15 is limited to the maximum output state IMAX within the range of the heat resistance of the motor 15 and the MOS-FET 10 by the current upper limit value setting unit 23 during the stall. State ISTD
When the accelerator is operated in the stall state of the electric motor, power is continuously consumed during the operation, whereas the power consumption in the operation is reduced by raising and lowering the battery by raising and lowering the battery. Waste can be suppressed, the extension of the traveling distance per charge of the electric vehicle, the extension of the maximum output continuation time during a stall, and the like can be reliably achieved to meet the needs of the market. In other words, in order to suppress the battery consumption, a method of suppressing the magnitude of the current and a method of shortening the outflow time are conceivable.In the present embodiment, the setting of raising and lowering the upper limit is repeated. The above methods have been successfully combined.

Further, according to the configuration of the present embodiment, it is possible to suppress an increase in the length of a system for radiating heat, and to reduce the size without increasing the cost. The temperature rise of the switching elements in the electric motor and the inverter is also suppressed, and it is not necessary to increase the temperature resistance. As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various changes may be made in the design without departing from the spirit of the invention described in the claims. You can do it.

For example, in step 402 of the current upper limit value setting unit 23 during stall according to the present embodiment, the first maximum current limit value STLMT is set as the maximum output as the limit value for the field current when the motor 15 is in the stall state. State I
MAX and the limited state ISTD are repeated, but when it is not necessary to increase the current value again, FIG.
As shown in graph (2), the motor temperature MTMP (or M
OS-FET temperature TTMP is MTMAX (or TTM)
AX), the first value is reached as shown in graph (3).
The maximum current limit value STLMT of the
Thereafter, as long as the flag STOOL = 1, the value of the first maximum current limit value STLMT may not be changed. At this time, the value of the first maximum current limit value STLMT after being reduced is a value equal to or less than ISTD (for example, ISTD).
(A value of 90% of D).

In the present embodiment, the upper limit value of the field current of the induction motor 15 has been obtained. However, the upper limit value of the torque current value in the vector control may be used. In this case, it is necessary to consider the existence of the exciting current.
Further, the case where the induction motor 15 is a synchronous motor may be used as a method for obtaining the upper limit value of the field current. Furthermore, it may be used as well if the induction motor 15 is a DC motor. In this case, the same effect may be obtained even when the field current is an armature current. In this case, the same effect as described above can be obtained.

[0060]

As can be understood from the above description, the electric vehicle control apparatus of the present invention wastes battery even when the motor is in a stall state and the accelerator operation amount is large for a long time. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of an electric vehicle having an electric control device according to an embodiment.

FIG. 2 is a block diagram showing a processing content configuration of the electric control device of FIG. 1;

[3] operation flowchart of the electric control device of FIG.

FIG. 4 is an operation flowchart of stall detection by the stall detection processing means of FIG. 2;

FIG. 5 is an operation flowchart of reverse rotation detection by the stall detection processing means of FIG. 2;

FIG. 6 is an operation flowchart for setting a first maximum current limit value by a current upper limit value setting means during stall in FIG. 2;

FIG. 7 is a timing chart for setting a first maximum current limit value by a current upper limit value setting unit during stall in FIG. 2;

8 is a diagram showing setting of another limit value by another current upper limit value setting unit in FIG. 2;

9 is an operation flowchart for setting a final current limit value by a final command value calculation unit in FIG. 2;

FIG. 10 is a timing chart for setting a first maximum current limit value by a current upper limit value setting unit during a stall in an electric control device according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery 7 Electric vehicle control device (microcomputer) 8 Accelerator 9 Motor rotation direction output device 10 Element (MOS-FET) 11 Element temperature sensor 12 Means for controlling motor (inverter) 13 Motor current sensor 14 Motor temperature sensor 15 Motor Reference Signs List 16 motor rotation angle detector 20 input processing means 21 current command calculation means 22 stall state detection means 23 current upper limit value setting means during stall 24 other upper limit value setting means 25 final current command value calculation means 26 inverter drive signal Transmission method of

[Procedure amendment]

[Submission date] June 11, 2001 (2001.6.1)
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

Further, in another specific embodiment of the electric vehicle control device according to the present invention, the electric motor is an AC motor, and the means for controlling the electric motor is an inverter.
When the temperature of the switching element in the inverter becomes equal to or higher than a predetermined value in the stall state, the current upper limit value setting means may set the current upper limit value to be reduced at least once, or The current upper limit setting means sets the current upper limit to be reduced when the temperature of the switching element is equal to or higher than a predetermined value, and sets the current when the temperature of the switching element is equal to or lower than the predetermined value. The upper limit value is set to be raised, or the current upper limit value setting means at the time of the stall is set to reduce the current upper value at least once when the temperature of the electric motor becomes a certain value or more in the stall state. Or the current upper limit value setting means at the time of the stall, when the temperature of the electric motor becomes a certain value or more. Is set to lower the current upper limit value, and if the temperature of the electric motor becomes equal to or lower than a certain value, the current upper limit value is set to be raised, or the current upper limit value setting means at the time of stall is a stall state. When the stall state continues for a certain period of time, the current upper limit value is set to be lowered at least once, or the stall current upper limit value setting unit lowers the current upper limit value when the stall state continues for a certain period of time. Make the settings,
Thereafter, the current upper limit is raised and lowered at regular intervals.
Is set to be repeated .

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroyuki Yamada 2477 Takaba, Hitachinaka City, Ibaraki Prefecture Inside Hitachi Car Engineering Co., Ltd. Within the Automotive Equipment Group (72) Inventor Kazuhito Ishida 2477 Takaba, Hitachinaka-shi, Ibaraki Prefecture Inside Hitachi Car Engineering Co., Ltd. F-term in the equipment group (reference) 5H115 PA08 PG04 PI13 PU09 PV09 PV24 QE04 QE08 QH06 QN02 QN09 QN10 SE06 TI05 TO05 TO12 TU02 TU06 TU09 TU20 TW01 TZ09 UI12 5H576 AA06 AA15 CC02 DD02 DD04 EE01 FF04 GG01 GG01 GG01 LL56 LL58 MM06 MM10

Claims (16)

[Claims] 1. An electric vehicle control device comprising a battery, a motor driven by the battery, and means for controlling the motor, the control device comprising: a stall state detection means for the motor;
A stall current upper limit value setting unit that sets a current value flowing through the electric motor to a stall current upper limit value based on an output signal of the stall state detection unit,
A control device for an electric vehicle, comprising: final current command value calculating means for suppressing a current value flowing through the electric motor to reduce power consumption of the battery when a stall is detected. 2. The stall state detection means detects a stall state based on a rotation speed of the electric motor, a rotation direction of the electric motor, a current value flowing through the electric motor, and an accelerator detection amount. 2. The control device for an electric vehicle according to claim 1. 3. The stall current upper limit value setting means is configured to determine the upper limit value based on a temperature of the motor or a temperature of an element provided in a means for controlling the motor, and an output signal from the stall state detecting means. The control device for an electric vehicle according to claim 1 or 2, wherein: 4. The electric device according to claim 1, wherein the stall current upper limit value setting unit sets the upper limit value to be equal to or less than a continuous rated current value of the electric motor. Control device for car. 5. The motor is an AC motor, the means for controlling the motor is an inverter, and the current upper limit value setting means at the time of a stall is such that a temperature of a switching element in the inverter is constant at a stall state. The electric vehicle control device according to any one of claims 1 to 4, wherein when the above condition is satisfied, the current upper limit value is set to be reduced at least once. 6. The stall current upper limit value setting means sets the current upper limit value to be reduced when the temperature of the switching element is equal to or higher than a predetermined value, and the temperature of the switching element is equal to or lower than the predetermined value. The control device for an electric vehicle according to claim 5, wherein the setting is made so as to raise the current upper limit value in the case of: 7. The stall current upper limit value setting means sets the current upper limit value to be reduced at least once when the temperature of the electric motor has reached a certain value or more in a stall state. Claims 1 to 5
The control device for an electric vehicle according to any one of claims 1 to 4. 8. The stall current upper limit value setting means sets the current upper limit value to be reduced when the temperature of the electric motor becomes equal to or higher than a certain value, and the temperature of the electric motor becomes equal to or lower than the certain value. 8. The electric vehicle control device according to claim 7, wherein a setting is made to increase the current upper limit value in the case of the occurrence. 9. The stall current upper limit value setting means sets the current upper limit value to be reduced at least once when the stall state continues for a certain period of time. The control device for an electric vehicle according to claim 1. 10. The stall current upper limit value setting means sets the current upper limit value to be reduced when the stall state continues for a predetermined time, and thereafter sets the current upper limit value to be increased at regular time intervals. The control device for an electric vehicle according to claim 9, wherein: 11. The stall state detecting means, wherein the state in which the rotation speed of the electric motor is 0, the value of the current flowing through the electric motor is positive, and the maximum value of the accelerator detection amount is maintained for a predetermined time or more. The electric vehicle control device according to any one of claims 1 to 10, wherein when it is determined that the vehicle is in a stalled state, the control device detects that the vehicle is in a stalled state. 12. The stall state detecting means prohibits detection of a stall state when the rotation of the motor is in a reverse direction in response to a rotation direction command from a means for controlling the motor. The electric vehicle control device according to any one of claims 1 to 11, wherein 13. The stall state detection means, wherein the stall state detection unit prohibits the detection of the stall state when the state of the maximum value of the accelerator detection amount continues for a predetermined time or more in the inclined state. Item 13. The control device for an electric vehicle according to any one of Items 1 to 12. 14. The control device, by raising and lowering upper limit value setting by the current upper limit value setting means at the time of the stall, said to generate a warning sound from the motor, to inform that the stall condition to the driver The control device for an electric vehicle according to any one of claims 1 to 13, wherein: 15. The electric vehicle control device according to claim 1, wherein the electric vehicle is an electric vehicle. 16. The control device for an electric vehicle according to claim 1, wherein the electric vehicle is a forklift.