JPH11332006A - Controller of electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller for an electric vehicle, wherein its brake performance when its regenerative brake is disordered is improved, while suppressing the accuracy reduction of the determination of its regenerative brake being disordered. SOLUTION: When the voltage of a regenerative charging system ranging from a traveling motor 8 to a battery 1 is increased, because the regenerative brake of an electric vehicle becomes disordered by the generation of the nonconformities of the associative circuit thereof, its regenerative brake is determined as being disordered, if the increase rate of an increasing signal voltage Vi or (Vi-Vb), when its regenerative brake is disordered exceeds a predetermined value. In this way, the disorder of the regenerative brake can be determined quickly, while suppressing the accuracy reduction for the determination of its regenerative brake being disordered to make its brake performance improvable, when its regenerative brake is disordered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle control device for controlling a driving motor of an electric vehicle.

[0002]

2. Description of the Related Art In a conventional electric vehicle control device that runs on a battery charged from a fixed power supply or an on-board engine, when the running motor is regeneratively braked, an error such as a blown fuse or a main relay is opened. When power supply to the battery is cut off through the power supply, regenerative braking becomes impossible.

For this reason, conventionally, when the input voltage of the inverter circuit exceeds a predetermined threshold value during regenerative braking, it is determined that regenerative braking is malfunctioning, the regenerative braking operation thereafter is prohibited, and the normal mechanical braking operation is performed. Double pressure is increased to secure braking force.

[0004]

However, in the conventional method for regenerative braking malfunction described above, it takes time from the occurrence of regenerative braking malfunction to the completion of the increase in brake pressure, and the braking force during this time also decreases. There is a problem that the braking distance is extended. Of course, if the threshold value is set to a small value, the detection of regenerative braking malfunction can be promptly performed, but the accuracy of the determination naturally decreases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an electric vehicle control device which improves braking performance when regenerative braking is malfunctioning while suppressing a decrease in accuracy of regenerative braking malfunction determination. The purpose is.

[0006]

According to the electric vehicle control apparatus of the first configuration of the present invention, the regenerative braking becomes unstable due to the occurrence of a circuit failure, and the regenerative charging circuit system from the driving motor to the battery is provided. Since the signal voltage composed of the voltage increases when the regenerative braking is malfunctioning, it is determined that the regenerative braking is malfunctioning when the rate of increase of the signal voltage exceeds a predetermined value.

With this configuration, it is possible to quickly determine the regenerative braking malfunction while suppressing a decrease in the accuracy of the regenerative braking malfunction determination, thereby improving the braking performance when the regenerative braking malfunction occurs. According to a second aspect of the present invention, in the electric vehicle control device according to the first aspect, the input voltage of the inverter circuit is further detected as a signal voltage.

Since the input voltage of the inverter circuit has less voltage fluctuation than the voltage of other parts of the circuit other than the voltage increase at the time of regenerative braking failure, the accuracy of regenerative braking failure determination can be improved. According to a third aspect of the present invention, in the electric vehicle control device according to the first aspect, a voltage difference between an input voltage of the inverter circuit and a voltage of the battery is further detected as a signal voltage.

With this configuration, in addition to the operation and effect described in the second aspect, the influence of the battery voltage fluctuation can be further eliminated, so that the determination accuracy can be improved. According to a fourth aspect of the present invention, in the electric vehicle control device according to any one of the first to third aspects, further, when the voltage difference between the input voltage of the inverter circuit and the voltage of the battery exceeds a predetermined threshold, regenerative braking is performed. Judge as malfunction.

[0010] In this manner, in addition to the above-described effects, it is possible to prevent erroneous determination due to a noise voltage having a small absolute value but a large change rate. Claim 5
According to the electric vehicle control device described above, a signal voltage (for example, an inverter input voltage) that increases when regenerative braking malfunction is detected
When the voltage difference between the battery voltage and the battery voltage exceeds a predetermined value during regenerative braking, it is determined that regenerative braking is malfunctioning.

With this configuration, the influence of the battery voltage fluctuation can be eliminated, so that the determination accuracy can be improved. According to the electric vehicle control device of the sixth aspect, when it is determined that the regenerative braking has failed due to the occurrence of a circuit failure, a braking force increase command is output to the mechanical brake device. Further, thereafter, a command is issued to the inverter circuit to stop regenerative braking with a predetermined time delay from the braking force increase command.

With this configuration, even after the regenerative braking malfunction is detected and the mechanical braking force increase command is issued, the regenerative braking is continued, so that the regenerative electric power can be stored in the capacitor. The braking distance of the electric vehicle can be reduced by converting the power into electrostatic energy.
Particularly, when the output of the mechanical braking force increase command and the regenerative braking stop are performed simultaneously, there is a delay time from the output of the mechanical braking force increase command to the actual increase of the mechanical braking force. During this period, the overall braking force as a whole due to the stop of the regenerative braking is low, but according to this configuration, the regenerative braking is temporarily continued even after the mechanical braking force increase command, so that extra charge is stored in the capacitor during this period. The above-mentioned overall braking force can be improved by the amount of the regenerated electric power.

According to a seventh aspect of the present invention, in the electric vehicle control device according to the sixth aspect, the regenerative braking is stopped when the input voltage of the inverter circuit is less than the maximum allowable voltage of the inverter circuit. When the value exceeds, the stop of the regenerative braking is commanded. With this configuration, the driving power can be recovered by the capacitor even after the mechanical braking force increase command based on the regenerative braking malfunction detection without impairing the safety of the inverter circuit, and the braking distance of the electric vehicle can be reduced. Can be planned.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the electric vehicle control device according to the present invention will be specifically described with reference to the following embodiments.

[0015]

Embodiment 1 An embodiment to which an electric vehicle control device of the present invention is applied will be described with reference to FIG. FIG. 1 is a block diagram of a circuit device for traveling of an electric vehicle including the electric vehicle control device. 1 is a vehicle-mounted battery serving as an input, 2 is a battery voltage detector, 3 is a fuse, 4a and 4b are main relays, 5 is an inverter input voltage detector, 6 is an input capacitor, and 7 is a known 6-arm bridge configuration. Three-phase inverter circuit (inverter circuit), 8 is a traveling motor,
Reference numeral 9 denotes a controller with a built-in microcomputer for supplying a drive signal to the inverter, determining various abnormal states such as overvoltage and overcurrent, and performing protection, and reference numeral 10 denotes a mechanical brake device (not shown).

Next, the operation of this embodiment will be described. The controller 9 supplies a drive signal to the inverter 7 based on a command from a higher-level controller that controls the entire vehicle (not shown), and also supplies the inverter circuit 7 and the traveling motor 8
Temperature, motor current, motor speed, battery voltage V
b) Detect the state of the inverter input voltage Vi and the like, and feed back the information to a higher-level controller (not shown).

The battery voltage detector 2 detects the battery voltage on the battery 1 side from the fuse 3 and the main relays 4a and 4b. The inverter input voltage detector 5 detects the battery voltage on the inverter circuit 7 side from the fuse and the main relay. The input voltage of the inverter circuit 7 is detected. When the driver steps on the brake, the controller 9 supplies a drive signal to the inverter circuit 7 so as to apply regenerative braking according to a command from the host controller.

In a normal state, the battery 1 is connected to the inverter circuit 7 so as to be able to exchange power, so that the battery voltage Vb is substantially equal to the inverter input voltage Vi, and the only difference that occurs is a voltage drop due to the resistance of the wiring. . In this normal state, the regenerative electric power flows into the battery 1, so that the rate of change of the inverter input voltage Vi during the regeneration is small.

On the other hand, if the fuse is blown or the main relay is opened due to some abnormality,
Since all the regenerative power flows into the input capacitor 5, the change rate (increase rate) dVi / dt of the inverter input voltage Vi sharply increases, and the change rate dVb / dt of the battery voltage Vb.
Becomes almost zero. Further, the difference between the two voltages (Vi-Vb) also increases as shown in FIG. Therefore, in this embodiment,
When the rate of change dVi / dt of the inverter input voltage Vi exceeds a predetermined threshold value Vth, regenerative braking is determined to be malfunctioning.

An example of the regenerative braking monitoring routine executed by the controller 9 will be described with reference to the flowchart shown in FIG. Note that this routine is started when a signal indicating that the driver has depressed the brake is input to the controller 9 and the controller 9 outputs a drive signal for regenerative braking to the inverter circuit 7. First,
The inverter input voltage Vi is detected (S100), and the rate of change dVi / dt is calculated (S102).

Next, the rate of change d of the inverter input voltage Vi
It is checked whether Vi / dt is greater than a predetermined threshold value Vth in the positive direction (S104). If it is greater, it is determined that regenerative braking is malfunctioning, and the mechanical brake device 10 is instructed to increase the brake double pressure and the inverter circuit 7 is activated. The output of the regenerative braking drive signal to the controller 9 is prohibited (S106). Otherwise, it is determined that there is no regenerative braking problem, and the process returns to the main routine of the controller 9.

In this way, the inverter input voltage V
Compared with the conventional determination method for determining whether or not i exceeds a predetermined threshold, the influence of the fluctuation or variation of the battery voltage Vb is avoided, and the regenerative braking malfunction is detected reliably and promptly immediately after the regenerative braking malfunction occurs. And as a result,
The brake pressure increase can be realized with a short delay time.

The threshold value Vth is set larger than the rate of change of the battery voltage Vb.

[0024]

Embodiment 2 Another embodiment to which the electric vehicle control device of the present invention is applied will be described with reference to FIG. This embodiment is different from the electric vehicle control device described in the first embodiment only in that the regenerative braking monitoring routine shown in FIG. 3 is changed.

In the regenerative braking monitoring routine of this embodiment, as shown in FIG.
i and Vb are detected (S200), and the rate of change d (Vi−
Vb) / dt is calculated (S202). Next, the rate of change d
It is checked whether (Vi−Vb) / dt is greater than a predetermined threshold value Vth in the positive direction (S204). If it is greater, it is determined that regenerative braking is malfunctioning, and a brake pressure increase is commanded. The output of the regenerative braking drive signal is prohibited (S206). Otherwise, it is determined that there is no regenerative braking problem, and the process returns to the main routine of the controller 9.

By doing so, the inverter input voltage V
Compared with the conventional determination method for determining whether or not i exceeds a predetermined threshold, the influence of the fluctuation or variation of the battery voltage Vb is avoided, and the regenerative braking malfunction is detected reliably and promptly immediately after the regenerative braking malfunction occurs. And as a result,
The brake pressure increase can be realized with a short delay time.

Particularly, in this embodiment, when the fuse 3 and the main relays 4a and 4b are not opened, the difference voltage (Vi-Vb) is obtained regardless of the fluctuation of the battery voltage Vb.
Is very small, so that an erroneous determination due to a change in the battery voltage Vb can be avoided.

[0028]

Embodiment 3 Another embodiment to which the electric vehicle control device of the present invention is applied will be described with reference to FIG. This embodiment differs from the electric vehicle control device described in the second embodiment only in that S205 is added to the regenerative braking monitoring routine shown in FIG.

That is, in the regenerative braking monitoring routine of this embodiment, as shown in FIG. 5, the rate of change d (Vi-V
b) If it is determined that / dt is greater than the predetermined threshold value Vth in the positive direction (S204), the difference between the two voltages (Vi)
It is determined whether or not −Vb) is greater than a predetermined threshold value Vth ′ (S205).

In this way, the fluctuation of the inverter input voltage Vi, whose absolute value is small but changes at a high speed, such as ripple of the inverter input voltage Vi and external electromagnetic noise caused by the switching operation of the inverter circuit 7, is regenerated. It is possible to prevent erroneous determination that braking is malfunctioning. Of course, the absolute value determination in S205 can be applied to the regenerative braking malfunction determination in the first embodiment shown in FIG.

[0031]

Embodiment 4 Another embodiment to which the electric vehicle control device of the present invention is applied will be described with reference to FIG. This embodiment is different from the electric vehicle control device described in the first embodiment only in that the regenerative braking monitoring routine shown in FIG. 3 is changed.

In the regenerative braking monitoring routine of this embodiment, as shown in FIG.
i and Vb are detected (S300), and the difference voltage Δ (Vi−
Vb) is calculated (S302). Next, the difference voltage Δ (Vi
It is checked whether or not −Vb) is larger than a predetermined threshold value Vth ′ in the positive direction (S304). If it is larger, it is determined that regenerative braking is malfunctioning, and an increase in brake pressure is commanded, and regenerative braking to the inverter circuit 7 is performed. The output of the drive signal is prohibited (S306). If not, it is determined that there is no regenerative braking problem, and the process returns to the main routine of the controller 9.

In this way, the inverter input voltage V
Compared with the conventional determination method for determining whether i exceeds a predetermined threshold value, the influence of the fluctuation or variation of the battery voltage Vb can be avoided, so that the regenerative braking malfunction can be determined more accurately. Since the threshold value can be reduced without lowering the determination accuracy by that amount, the determination can be made quickly, and a rapid increase in brake pressure can be expected.

In each of the above-described embodiments, the operation sequence of increasing the brake pressure increase and inhibiting the regenerative braking after the regenerative braking malfunction is determined is arbitrary. In each of the above embodiments, at least the inverter input voltage Vi is used for regenerative braking malfunction detection. However, if the voltage is linked to an increase in the voltage of the traveling motor 8 at the time of regenerative braking malfunction, the main relay 4a will It goes without saying that voltages of other parts in the circuit up to the motor 8 may be used.

[0035]

Embodiment 5 Another embodiment to which the electric vehicle control device of the present invention is applied will be described with reference to FIG. This embodiment is different from the electric vehicle control device described in the first embodiment only in that the regenerative braking monitoring routine shown in FIG. 3 is changed.

The regenerative braking monitoring routine of this embodiment is as follows.
This is executed at the same time as the start of regenerative braking. As shown in FIG. 7, first, it is determined whether regenerative braking is malfunctioning, and if not, the process returns to the main routine (S400). Note that this determination itself can employ the same determination method as in the above-described first to fourth embodiments. If it is determined that the regenerative braking is malfunctioning, the mechanical brake device 10 is instructed to increase the brake double pressure (S402). Then, the input voltage, that is, the terminal voltage Vi of the capacitor 5 is increased to a predetermined threshold voltage. Vt
It is checked whether h '' has been exceeded (S404), and the process waits until the value exceeds h ''. If the value exceeds h '', the inverter circuit 7 is instructed to stop the braking operation (S406), and the process returns to the main routine of the controller 9.

The threshold voltage Vth ″ is set as high as possible within a range lower than the maximum allowable voltage value of the inverter circuit 7 and the capacitor 6. However,
After stopping the regenerative braking, the input voltage Vi slightly increases due to the emission of the electromagnetic energy from the motor 8, so that the threshold voltage Vth ″ should be set in consideration of this increase.

In this way, regenerative braking malfunction is detected (S400), and a mechanical braking force increase command is issued (S40).
2) After that, the input voltage Vi is still higher than the threshold voltage Vth ″.
Until the regenerative electric power is stored in the capacitor 5, the regenerative braking is continued, so that the regenerative braking effect can be further improved. It is needless to say that a part of the regenerative electric power can be consumed by the wiring, the inverter circuit or the like when the regenerative braking is excessively continued.

Further, in this embodiment, the main relay 4a,
The same effect as described above can be exerted even in a state where regenerative braking is not complete but operable due to incomplete conduction of 4b or partial opening of wiring connecting inverter circuit 7 and battery 1. .

[Brief description of the drawings]

FIG. 1 is a block diagram of a driving circuit device of an electric vehicle including an electric vehicle control device according to a first embodiment.

FIG. 2 is a timing chart showing a time change of a battery voltage Vb, an inverter input voltage Vi, a change rate dVi / dt of the inverter input voltage Vi, and a brake double pressure in the electric vehicle control device of the first embodiment.

FIG. 3 is a flowchart illustrating a regenerative braking monitoring routine in the electric vehicle control device according to the first embodiment.

FIG. 4 is a flowchart illustrating a regenerative braking monitoring routine in the electric vehicle control device according to the second embodiment.

FIG. 5 is a flowchart illustrating a regenerative braking monitoring routine in the electric vehicle control device according to the third embodiment.

FIG. 6 is a flowchart illustrating a regenerative braking monitoring routine in the electric vehicle control device according to the fourth embodiment.

FIG. 7 is a flowchart illustrating a regenerative braking monitoring routine in the electric vehicle control device according to the fifth embodiment.

[Explanation of symbols]

1 is a battery, 5 is an inverter input voltage detector (voltage detection means), 6 is a capacitor, 7 is an inverter circuit, 8 is a running motor, 9 is a controller (voltage increase rate calculation means, regenerative braking malfunction determination means, mechanical control). Power increase command means (s402), regenerative braking stop means (s406))

Claims (7)

[Claims] 1. An inverter circuit interposed between a battery charged from a fixed power supply or a vehicle-mounted engine and a traveling motor to drive and regeneratively brake the traveling motor, and to increase when the regenerative braking is out of order. Voltage detecting means for obtaining a signal voltage; voltage increasing rate calculating means for calculating an increasing rate of the signal voltage; regenerative braking for determining that regenerative braking is malfunctioning when the increasing rate of the signal voltage exceeds a predetermined value during regenerative braking An electric vehicle control device, comprising: a malfunction determination unit. 2. The electric vehicle control device according to claim 1, wherein said voltage detecting means detects an input voltage of said inverter circuit as said signal voltage. 3. The electric vehicle control device according to claim 1, wherein said voltage detecting means detects a voltage difference between an input voltage of said inverter circuit and a voltage of said battery as said signal voltage. Control device. 4. The electric vehicle control device according to claim 1, wherein the regenerative braking malfunction determination unit determines that the rate of increase of the signal voltage exceeds a predetermined value during the regenerative braking, and the inverter circuit An electric vehicle control device characterized in that when the voltage difference between the input voltage of the battery and the voltage of the battery exceeds a predetermined threshold value, it is determined that regenerative braking is malfunctioning. 5. An inverter circuit interposed between a battery charged from a fixed power supply or a vehicle-mounted engine and the traveling motor to drive the regenerative motor and perform regenerative braking, and increases when the regenerative braking is detected. Voltage detecting means for obtaining a signal voltage and a battery voltage, and regenerative braking malfunction determining means for determining regenerative braking malfunction when a voltage difference between the signal voltage and the battery voltage exceeds a predetermined value during regenerative braking. Characteristic electric vehicle control device. 6. An inverter circuit interposed between a battery charged from a fixed power supply or a vehicle-mounted engine and a traveling motor to drive and regeneratively brake the traveling motor, and between an input terminal pair of the inverter circuit. A regenerative braking malfunction determining means for determining a malfunction of the regenerative braking; a mechanical braking force increasing command means for outputting a braking force increasing command to a mechanical brake device when the regenerative braking malfunction is determined; An electric vehicle, comprising: regenerative braking stop means for instructing the inverter circuit to stop the regenerative braking after a predetermined time delay from the braking force increase command to the mechanical brake device when the regenerative braking malfunction is determined. Control device. 7. The electric vehicle control device according to claim 6, further comprising: voltage detection means for detecting an input voltage of the inverter circuit, wherein the regenerative braking stop means has a maximum allowable value of the detected input voltage of the inverter circuit. An electric vehicle control device for commanding stop of the regenerative braking when a predetermined threshold voltage lower than a voltage is exceeded.