JPH08237805A - Regenerative braking apparatus - Google Patents

Abstract

PURPOSE: To provide a regenerative braking apparatus by which the regenerative amount of electric energy generated in a braking operation is increased and whose changing capability is enhanced by a method wherein, when the step-m amount of an accelerator pedal becomes zero and a vehicle speed at this time is at a threshold value or higher, a braking pedal is controlled automatically so as not to exceed the vehicle speed. CONSTITUTION: When an accelerator pedal 21 is not stepped on, it is judged whether a vehicle speed from a vehicle speed sensor is at a threshold value or higher. When the vehicle speed does not exceed the threshold value, the regenerative operation of electric energy is continued. When the vehicle speed exceeds the threshold value, a braking pedal is controlled so as not to exceed the present vehicle speed. When a brake pedal 22 or the accelerator pedal 21 is not stepped on during the execution of a braking level control operation, the regenerative operation of the electric energy is continued as it is. Thereby, it is possible to obtain a regenerative braking apparatus which can increase the regenerative amount of the electric energy when a car which is provided with an electric braking device and with an auxiliary accelerating device goes down a hill and whose charging capability can be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used for regenerative braking of automobiles. The present invention is a technique suitable for an electric vehicle that uses electric energy regenerated by braking for traveling.

The present invention is an invention relating to an electric braking and auxiliary accelerator for an automobile, which is manufactured and sold by the applicant under the name of HIMR and is disclosed in International Publication WO88 / 06107 (International Application No. PCT / JP88 / 00157). However, it can be widely used for vehicles other than this vehicle.

[0003]

2. Description of the Related Art Conventionally, as an apparatus of this type, an electric braking and auxiliary acceleration apparatus for an automobile disclosed in the above-mentioned International Publication WO08 / 08107 (International Application No. PCT / JP88 / 00157) by the present applicant has been known. Has been.

In this device, as shown in FIG. 6, a squirrel-cage induction machine 2 whose rotor portion is directly connected to an internal combustion engine 1, a battery 3, and a DC voltage of the battery 3 are connected to the squirrel-cage induction machine 2. It is converted into an AC voltage having a frequency suitable for inducing a rotating magnetic field having a rotation speed lower than the shaft rotation speed, and this is converted into a squirrel cage induction machine
And an inverter circuit 4 for converting the AC power from the squirrel cage induction machine 2 into DC power, and this inverter circuit 4
And a control circuit 5 for generating a control signal for setting the frequency of the AC side voltage. The control circuit 5 includes means for generating a control command by the driver according to the driving of the automobile.

Further, a rotation sensor 6 is attached to the squirrel cage induction machine 2, a signal from the rotation sensor 6 is given to a control circuit 5, and the control circuit 5 is further provided with information on the charging state of the battery 3. To enter.

A capacitor 7 and a semiconductor switch circuit 12 are connected to the output side of the inverter circuit 4, and a resistor 11 is connected via the semiconductor switch circuit 12.
This resistor 11 is designed to dissipate when the vehicle is heavily braked and excessive electrical energy is generated which cannot be regenerated.

Further, the battery 3 and the semiconductor switch circuit 12 are connected to a detection circuit 13 for detecting the output voltage of the inverter circuit 4, and the resistor 11 is provided with a current detector 15 for detecting a change in current. A switch control circuit 14 that controls the semiconductor switch circuit 12 according to the detection signal is connected to the current detector 15. The detection circuit 13 is connected to the switch control circuit 14.

The conventional apparatus thus configured has a starting mode, an auxiliary acceleration mode, and a braking mode as operation modes, and when any one of the modes is set as necessary, the squirrel cage induction is performed. It is a very useful device that can operate a machine as an electric motor or a generator to start an internal combustion engine, assist acceleration during running, electric braking, and regenerate electric energy to a battery.

[0009]

Among these modes, the braking mode according to the present invention is controlled by the main shaft of the internal combustion engine by controlling so that the slip of the rotating magnetic field given to the squirrel cage induction machine keeps a negative value. The squirrel cage induction machine is rotated to brake the internal combustion engine, and the electric energy generated at this time is regenerated in the battery. This operation is performed each time electric braking is performed, but since the amount of electric energy regenerated is designed as shown in FIG. 3 depending on the gear position of the transmission, a smaller gear ratio (for example, 2nd speed) is given to the driver when going downhill. When is set, the rotation speed of the internal combustion engine decreases and the amount of electric energy regenerated is extremely small. On the other hand, when the driver sets a large gear ratio, the vehicle accelerates and the driver must depress the brake pedal. Also in this case, there is a problem that the regenerative energy becomes small.

The present invention has been made against such a background, and provides an apparatus capable of increasing the amount of electric energy regenerated during a downhill to improve the charging ability and improve the driving operability. The purpose is to do. An object of the present invention is to provide a device capable of automatically and efficiently regenerating electric energy generated during braking.

[0011]

The present invention is characterized in that electric energy generated during braking by electric braking means is efficiently regenerated without being restricted by the position of the transmission.

That is, the present invention provides a regenerative braking device comprising electric braking means, a battery charged by the electric energy generated by the electric braking means, and a control circuit for controlling the braking level of the electric braking means. , A vehicle speed sensor and an accelerator sensor for detecting displacement of the accelerator pedal, the control circuit takes in the outputs of the two sensors, and when the accelerator pedal depression amount becomes zero, the vehicle speed at that time is equal to or more than a threshold value. If any, it further comprises means for automatically controlling the braking level so as not to exceed the vehicle speed.

A brake sensor for detecting the operation of the brake pedal is provided, and the control circuit takes in the output of the brake sensor and automatically controls when the brake pedal is depressed or the accelerator pedal is depressed. Means for releasing the means, which means that the brake pedal is depressed when the accelerator pedal is zero,
If the vehicle speed at that time is equal to or higher than the threshold value when the brake pedal is released thereafter, it is desirable to provide means for automatically controlling the braking level so as not to exceed the vehicle speed. The electric braking means is a squirrel cage induction machine directly connected to a crankshaft of an internal combustion engine, and the control circuit controls the braking level by controlling the rotational speed of a rotating magnetic field applied to the squirrel cage induction machine. Can be

[0014]

The electric energy generated by the electric braking means when electric braking is performed on a downhill or the like is regenerated in the battery according to a predetermined braking level. At this time, the output from the vehicle speed sensor that detects the vehicle speed and the output from the accelerator sensor that detects the displacement of the accelerator pedal are taken in, and when the accelerator pedal depression amount becomes zero, that is, the driver accelerates. When the vehicle speed when not performing is above a predetermined threshold value (for example, 30 km / h), the control level is automatically controlled so as not to exceed the vehicle speed at that time or to maintain the vehicle speed at that time. . As a result, the amount of electric energy regenerated to the battery can be increased, and the regeneration of electric energy can be improved even if the transmission is set at an optimal position by the driver.

When the operation of the brake pedal is detected by the brake sensor or when the accelerator sensor detects that the accelerator pedal is depressed during such electric braking, the control circuit brakes at will of the driver. Alternatively, the above control is canceled assuming that acceleration has been performed.

The brake pedal is depressed when the accelerator pedal is zero, and the brake pedal is released thereafter, that is, braking is performed without the driver's intention to accelerate, and then If the vehicle speed when the braking is released is equal to or more than the threshold value, the control circuit maintains the current vehicle speed and automatically controls the braking level so as not to exceed the vehicle speed.

In practice, a squirrel cage induction machine directly connected to the crankshaft of an internal combustion engine is used as the electric braking means.
In this case, the braking level is changed and set by controlling the rotation speed of the rotating magnetic field applied to the squirrel cage induction machine by the control circuit.

[0018]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention.

In the embodiment of the present invention, the electric braking means, the battery 3 charged by the electric energy generated by the electric braking means, the control circuit 5 for controlling the braking level of the electric braking means, and the vehicle speed sensor 16 are provided. , An accelerator sensor 17 for detecting the displacement of the accelerator pedal 21, and a brake pedal 2
The brake circuit 18 for detecting the operation of No. 2 is further provided, and the control circuit 5 further takes in the outputs of the two sensors, and when the depression amount of the accelerator pedal 21 becomes zero, if the vehicle speed at that time is equal to or more than the threshold value, Means for automatically controlling the braking level so as not to exceed the vehicle speed, and the brake sensor 18
And a means for canceling the control operation of the means for automatically controlling when the brake pedal 22 is depressed or the accelerator pedal 21 is depressed. When the brake pedal 22 is stepped on when the amount of depression is zero, and then the brake pedal 22 is released, if the vehicle speed at that time is equal to or greater than a threshold value, the braking level is automatically controlled so as not to exceed the vehicle speed. Means for doing so.

In the electric braking means, a squirrel cage induction machine 2 whose rotor is directly connected to a crankshaft of an internal combustion engine 1 and a DC voltage of a battery 3 are rotated at a rotation speed lower than a rotation speed of the squirrel cage induction machine 2. And an inverter circuit 4 for converting the AC voltage of the frequency suitable for inducing the rotating magnetic field of the above to the cage induction machine 2 and for converting the AC power from the cage induction machine 2 into the DC power, The circuit 5 includes means for generating a control signal for setting the frequency of the AC side voltage of the inverter circuit 4.

Further, the cage type induction machine 2 has a rotation sensor 6
When the capacitor 7 and the semiconductor switch circuit 12 connected to the output side of the inverter circuit 4 are connected to the semiconductor switch circuit 12 and excessive braking energy is applied to the semiconductor switch circuit 12 and an excessive amount of electric energy that cannot be regenerated is generated. A resistor 11 for dissipating, a detection circuit 13 for detecting the output voltage of the inverter circuit 4, a current detector 15 for detecting a change in the current flowing through the resistor 11, and a semiconductor switch according to the detection output of the current detector 15. Circuit 12
And a switch control circuit 14 for controlling. A DC / DC converter 19 is connected to the battery 3.

Next, the operation of the embodiment of the present invention configured as described above will be described. The operation performed by the electric braking means is roughly classified into a start mode, an auxiliary acceleration mode,
And there is a braking mode. First, the operation of the braking mode according to the present invention will be described.

When the braking mode is set by operation, the control circuit 5 causes the rotation sensor 6 to detect the squirrel cage induction machine 2.
A rotating magnetic field having a speed smaller than the rotating speed of the rotor unit is applied to the stator unit to control the slip of the rotating magnetic field to be negative.
As a result, power is generated, the internal combustion engine 1 is loaded, and braking is performed. The electric energy generated at this time is converted into DC energy by the inverter circuit 4 and supplied to the battery 3 as a charging current.

When the braking torque is large and the battery 3 cannot absorb this DC energy, the DC terminal voltage rises above a predetermined value, and the detection circuit 13 detects this and the switch receiving this detection output. The control circuit 14 controls the semiconductor switch circuit 12 to connect the resistor 1 to the terminal of the battery 3.
Connect 1. Excessive electrical energy is dissipated from the resistor 11.

The automatic control operation of the braking level in the braking mode, which is a feature of the present invention, will be described. FIG. 2 is a flow chart showing the flow of the braking level automatic control operation in the embodiment of the present invention.

When the braking mode is set by the driver's operation, the control circuit 5 takes in the rotation speed of the internal combustion engine 1 from the rotation sensor 6 and the vehicle speed V from the vehicle speed sensor 16 so that the current gear position is changed. Determine which one it is. As shown in the example of FIG. 3, the amount of regenerated electric energy is designed so that the level varies depending on the gear position (2nd speed to 5th speed) of the transmission, and therefore the braking level at the currently set gear position. To regenerate electric energy.

If there is an output from the accelerator sensor 17 indicating that the accelerator pedal 21 has been stepped on during the regeneration of this electric energy, it is assumed that the driver has an intention to accelerate, and the braking level control is released to set the current gear position. Continue to regenerate electrical energy at the braking level.

If the accelerator pedal 21 is not depressed, the vehicle speed V from the vehicle speed sensor 16 is the threshold value T (for example, 30 km /
h) It is determined whether or not it is not less than, and if the threshold value T is not exceeded, regeneration of electric energy is continued. If it exceeds the threshold value T, the braking level is controlled so as not to exceed the current vehicle speed V. In this braking level control, as shown in FIG. 4, in the internal combustion engine 1 designed for each gear position of the transmission, the characteristic value indicating the regeneration amount of the electric energy with respect to the rotation speed is within the range from solid line to broken line + S to -S. It is done by changing to. This is done by changing the amount of negative slip of the rotating magnetic field applied to the squirrel cage induction machine 2.

Actually, even if the braking level is controlled so as not to exceed the current vehicle speed, there is a limit to the change of the negative slip amount of the rotating magnetic field given to the squirrel cage induction machine 2, and it cannot be handled. Sometimes. FIG. 5 is a flowchart showing the flow of operations in that case.

In the control circuit 5, the vehicle speed V shown in FIG.
After confirming the following, it is determined whether or not the vehicle speed V is increasing. If the vehicle speed V has not risen, the amount of slip given to the rotating magnetic field is maintained as it is. Vehicle speed V
If is increased, the slip amount S is changed, and whether or not the changed value S exceeds the change limit value Slimit (for example, 5%) of the slip amount, that is, | S |> | Slimit | To determine.

If the change value S does not exceed the limit value Slimit, the process returns to the vehicle speed conversion determination, and if it exceeds the limit value, an alarm is issued to prompt the driver to change the transmission gear position. This alarm is issued by displaying it on a display provided in the driver's seat. Next, it is determined whether the gear position of the transmission has been changed, and if not changed, the alarm is continued. If it has been changed, the process is returned to the vehicle speed change determination.

If the brake pedal 22 or the accelerator pedal 21 is not depressed during execution of this braking level control,
Continue to regenerate electric energy. If the brake pedal 22 or the accelerator pedal 21 is depressed,
Assuming that braking or acceleration has been performed, the braking level control is released, and it is determined what pedal is depressed.

If the accelerator pedal 21 is used, the regeneration of electric energy at the braking level at that gear position is continued. If it is the brake pedal 22, it is determined whether or not it is released after being stepped on. If it is not released, the braking is continued because the braking is continued, and if it is released, the transmission is released. Regeneration of electric energy is continued according to the braking level according to the gear position.

[0034]

As described above, according to the present invention, it is possible to increase the amount of electric energy regenerated when a vehicle equipped with a device for performing electric braking and auxiliary acceleration is downhill, thereby increasing the charging capacity. This has the effect of improving the driving operability as well as improving the driving performance.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing the flow of the overall operation of the braking level automatic control in the embodiment of the present invention.

FIG. 3 is a diagram showing a series of design values of the electric energy regeneration amount in the embodiment of the present invention.

FIG. 4 is a diagram for explaining slip of a rotating magnetic field in the example of the present invention.

FIG. 5 is a flowchart showing the flow of braking level control in the embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

 1 Internal Combustion Engine 2 Cage Induction Machine 3 Battery 4 Inverter Circuit 5 Control Circuit 6 Rotation Sensor 7 Capacitor 11 Resistor 12 Semiconductor Switch Circuit 13 Detection Circuit 14 Switch Control Circuit 15 Current Detector 16 Vehicle Speed Sensor 17 Accelerator Sensor 18 Brake Sensor 19 DC / DC converter 21 Accelerator pedal 22 Brake pedal

Claims (4)

[Claims] 1. A regenerative braking device comprising: an electric braking means; a battery charged by electric energy generated by the electric braking means; and a control circuit for controlling a braking level of the electric braking means, a vehicle speed sensor, An accelerator sensor for detecting a displacement of an accelerator pedal, wherein the control circuit takes in the outputs of the two sensors, and when the accelerator pedal depression amount becomes zero, the vehicle speed at that time is equal to or more than a threshold value, the vehicle speed. And a means for automatically controlling the braking level so as not to exceed the limit. 2. A brake sensor for detecting the operation of a brake pedal is provided, and the control circuit takes in the output of the brake sensor and automatically outputs the brake pedal when the brake pedal is depressed or the accelerator pedal is depressed. The regenerative braking device according to claim 1, further comprising means for releasing the means for controlling. 3. The brake pedal is depressed when the amount of depression of the accelerator pedal is zero, and when the brake pedal is subsequently released, if the vehicle speed at that time is equal to or more than the threshold value, the vehicle speed is not exceeded. 3. The regenerative braking device according to claim 2, further comprising means for automatically controlling the braking level. 4. The braking means is a squirrel cage induction machine directly connected to a crankshaft of an internal combustion engine, and the control circuit controls the rotation speed of a rotating magnetic field applied to the squirrel cage induction machine. The regenerative braking device according to claim 1, wherein the regenerative braking device is configured to control a level.