JPH0612932B2 - Secondary battery charge control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used for an electric braking device of an automobile. In particular, it is used for an electric braking device having a structure in which the electric energy generated from the electric braking device is regenerated in the secondary battery.

[Conventional technology]

A technique for regenerating electric energy generated by an electric braking device in a secondary battery at the time of braking has been researched, but the techniques up to now are not necessarily satisfactory and have not been applied to commercially available automobiles.

However, by using a squirrel-cage polyphase induction machine and controlling the rotation speed of the rotating magnetic field applied to the stator of this squirrel-cage polyphase induction machine, the squirrel-cage polyphase induction machine is operated as a generator to generate a braking device. In addition, a technique for operating as an electric motor to form an auxiliary drive device has been developed. The inventors of the present application have conducted a test of this technology and found that, when this technology is used, the electric energy generated by braking is regenerated in a considerable proportion in the secondary battery, and this can be effectively used as a power source for auxiliary power. It was

On the other hand, a secondary battery mounted on a conventional vehicle is designed and controlled so that the secondary battery is always charged to almost 100% of its rated charge capacity and the charged energy is used.
That is, in the conventional control method, the secondary battery is charged by the generator connected to the internal combustion engine, and charging is continued as long as the internal combustion engine is rotating. When the charging energy is used by the operation of the starter motor or the operation of various outfitting devices, the charging circuit is controlled so as to reach the full charge state of the rated charge capacity in the shortest possible time.

[Problems to be solved by the invention]

However, as described above, under the technology of regenerating the energy generated by braking as an electric energy in a secondary battery mounted on a vehicle, and using the energy charged in the secondary battery as an auxiliary power for vehicle traveling, If the secondary battery is always charged to the rated charge capacity, the energy generated by braking cannot be efficiently regenerated and used.
That is, it is not possible to make the fuel used in an automobile more efficient with the above technology.

It is an object of the present invention to provide a vehicle-mounted secondary battery charge control method capable of efficiently regenerating and utilizing electric energy to the secondary battery.

[Means for solving problems]

The present invention is characterized in that the state of charge of the secondary battery is maintained at a predetermined target capacity smaller than its rated charge capacity, for example, 50 to 70.

[Action]

The braking device cannot predict the occurrence state in advance according to the driving state of the vehicle, and always occurs in an unexpected situation. As mentioned above, the charge capacity of the secondary battery is set to be small rather than the full charge rated capacity. As a result, when electric energy is generated by electric braking, the secondary battery has a margin for regenerative charging. By utilizing the regeneratively charged energy as the auxiliary driving force, the fuel consumption of the internal combustion engine can be reduced accordingly.

The predetermined target capacity is the performance of the braking system, the operating condition of the vehicle,
It is a value that should be selectively designed according to the absolute capacity of the secondary battery, operating temperature, and various other conditions. If this target capacity is set close to 100%, the energy generated by braking cannot be efficiently regenerated. Also,
If it is set too low, inconvenience will occur when starting is repeated many times depending on operating conditions. Therefore, it is appropriate to set the target capacity to 50% or more and 70% or less.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

The figure is a block diagram of an apparatus according to an embodiment of the present invention. The rotary shaft of the cage multiphase induction machine I is directly connected to the internal combustion engine En of the automobile. This cage type polyphase induction machine I has a rotation sensor S
S is attached. This automobile is equipped with a DC power supply device E including a secondary battery. Inverter means In is inserted between the DC terminal of the DC power supply device E and the AC terminal of the cage multiphase induction machine I. The inverter means In uses a DC power source to apply a rotating magnetic field to the stator of the cage-type multiphase induction machine I, and converts the alternating current generated by the braking of the stator of the cage-type polyphase induction machine I into DC. The DC power supply device E is regeneratively charged.

Further, a discharge resistor R is connected to the DC power supply device E through a switch circuit SW, and when the vehicle is suddenly braked and excessive electric energy that cannot be regenerated is generated, the discharge resistor R is connected to the discharge resistor R. It is configured to be dissipated by.

A control signal for giving a rotating magnetic field corresponding to the rotation of the rotor to the stator of the squirrel cage multiphase induction machine I is supplied to the inverter means In from the squirrel cage multiphase induction machine CONT. The rotation information from the rotation sensor SS is input to the control circuit CONT, and the information of the DC power supply device E regarding the charging state of the secondary battery is input. This control circuit CO
NT includes a microprocessor. Further, the control circuit CONT includes means for taking in an operation control signal which changes according to the driving condition by the driver's operation.

As described above, this inverter device In can supply the energy of the DC side terminal to the AC side terminal and the energy generated at the AC side terminal to the DC side terminal. Further, by controlling the control circuit CONT, the rotation speed of the rotating magnetic field is controlled so that the squirrel cage polyphase induction machine I becomes an electric motor, and a driving force is applied to the rotation shaft of the squirrel cage polyphase induction machine I to generate the internal combustion engine En. Can be operated as an auxiliary drive device of the. At this time, the electric energy charged in the DC power supply device E is used.

The inverter means In is specially designed here for an automobile, but its basic technique is known as a technique for elevators, cranes and the like.

Here, the device of the present invention is characterized in that the charging state of the secondary battery of the DC power supply device E is controlled so as to reach a predetermined target capacity smaller than its rated charging capacity in a steady state. As the target capacity, 50 to 70% is suitable as described above.

By doing so, electric braking is performed as the vehicle is driven, and when electric energy is generated, it can be regenerated by the secondary battery of the DC power supply device E. If the secondary battery is 100% of the rated charging capacity as in the conventional method, it cannot be regeneratively charged.

When the electric energy regenerated and charged in this manner gradually increases and exceeds the predetermined target value, a warning is issued to the driver to urge the driver to actively use the auxiliary driving force. As a result, the charged electric energy is given to the squirrel cage polyphase induction machine I to generate power and be effectively used.

Regarding the information for monitoring the state of charge of the secondary battery and transmitting it to the control circuit CONT, the method of observing and identifying the terminal voltage of the secondary battery is used in the above embodiment. According to this method, the state of charge can be monitored although the accuracy is low. In order to further improve accuracy, there are a method of monitoring the specific gravity of the electrolytic solution of the secondary battery, a method of measuring and integrating the charge and discharge of the secondary battery, and the like.

When the charge capacity exceeds a predetermined target value, the driver is alerted to use the auxiliary driving force to reduce the fuel consumption of the internal combustion engine, and the microprocessor incorporated in the control circuit CONT A method may be used in which information is taken in and the squirrel cage multiphase induction machine I is automatically operated as a motor during steady operation in accordance with the depression amount of the accelerator pedal operated by the driver.

The present invention can be similarly applied to not only the electric braking device based on the squirrel cage polyphase induction machine shown in the above example but also other types of electric braking devices that regenerate the generated electric energy.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention has an advantage that the energy generated when the vehicle is braked can be effectively regenerated by the secondary battery. In particular, when this regenerated energy is used for the auxiliary driving force of the automobile, there is an effect of reducing the fuel consumption by the internal combustion engine.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing an electrical configuration of an embodiment of the present invention. En ... Internal combustion engine, I ... Cage type multi-phase induction machine, SS ...
Rotation sensor, In ... Inverter means, CONT ... Control circuit, E ... DC power supply device including secondary battery. , SW ...
… Switch circuit, R… Discharge resistance.

Continued Front Page (72) Inventor Atsushi Obata 3-1-1 Hinodai, Hino City, Tokyo Hino Motors Ltd. (72) Inventor Koji Sasaki 1-1-1 Shibaura, Minato-ku, Tokyo Toshiba Corporation In the head office (72) Inventor Hiroshi Uchino No. 1 Toshiba-cho, Fuchu-shi, Tokyo Inside the Fuchu factory, Toshiba Corporation

Claims (3)

[Claims] 1. A charging control method for a secondary battery, wherein an electric braking device and a secondary battery are mounted on one automobile, and electric energy generated from the electric braking device is regenerated to charge the secondary battery. A charging control method for a secondary battery, characterized in that the state of charge of the secondary battery is maintained at a predetermined target capacity that is smaller than its rated charging capacity. 2. The charge control method for a secondary battery according to claim 1, wherein the predetermined target capacity is 50% to 70% of the rated charge capacity. 3. The electric braking device according to claim 1, further comprising a squirrel-cage polyphase induction machine and means for controlling a rotation speed of a rotating magnetic field applied to the squirrel-cage polyphase induction machine. Secondary battery charge control method.