JPH1059261A - Battery control method of electric-motor car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To utilize the capacity of the battery of an electric-motor car sufficiently, and to allow to use plural sorts (capacities) of batteries. SOLUTION: Normally, a microcomputer 31 reads a torque signal with the ratio according to the input torque and the car speed of a bicycle from its inner memory, controls an FET element 34 by modulating the pulse width of an FET drive circuit 33 depending on this torque signal and an input torque signal from a torque detecting circuit 35, and controls the drive of a motor 8 for assist. And, a finish voltage V - a current I standard value of the battery is memorized in the memory of the microcomputer 31, the battery voltage is detected by resistances R1 and R2 during the motor driving, while the current is detected by a resistance R3, to input them to the microcomputer 31, and when the voltage and the current are less than a standard value at 5.0 Ah, the duty ratio of the pulse width modulation of the FET drive circuit 33 is reduced and controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery control suitable for use in an electric vehicle including an electric bicycle, which is a so-called assisted bicycle, which assists human driving force by a motor driving force. The present invention relates to a battery control method for an electric vehicle that enables the use of a common battery.

[0002]

2. Description of the Related Art Recently, both a human-powered drive unit and a motor-driven electric drive unit are provided, and a motor is driven in accordance with the magnitude of the manual drive force, and the human-powered drive force is assisted by the motor drive force. Electric bicycles are gaining in popularity.

Here, an electric bicycle of the type in which the rear wheel is directly rotated by an electric motor provided by the present applicant, a so-called electric bicycle,
An example of an assist type electric bicycle of a rear-wheel direct drive type will be described with reference to the drawings.

FIG. 1 is an overall perspective view of an electric bicycle of a rear-wheel direct drive type, in which 1 is an electric bicycle main body.
The electric bicycle body 1 is provided with a motor 8 to be described later. The driving force of the motor 8 is changed in accordance with the magnitude of the torque by human power, and the electric power is driven by assisting the power of the motor 8 by the power of the motor 8. Has become.

[0005] A front wheel 2, a rear wheel 3, a handle 13 and a saddle 21 are mounted on a frame 4 of the electric bicycle main body 1, and the front wheel 2 is steered by the handle 13. A disk-shaped casing 5 is provided on the rotation shaft of the rear wheel 3.
Is provided.

The disc-shaped casing 5 has a rotating casing 6 and a fixed casing 7 fixed to the electric bicycle main body 1. The rotating casing 6 rotates integrally with the rear wheel 3. I have.

A motor 8 is built in the board-shaped casing 5 and is driven when electric driving is required to rotate the rotating casing 6 together with a human-powered driving unit 10 described later. The driving portion including the disc-shaped casing 5 is the electric driving unit 9.

The human-powered drive unit 10 includes a pedal 11 and a chain 12, and when the user steps on the pedal 11,
The rear wheel 3 is rotated via the chain 12. In this example, the chain 12 is a transmission member of human power. However, the invention is not limited thereto, and a chain, a rotating shaft, or the like may be used instead of the chain 12.

Brake levers 14 and 15 are attached to both left and right ends of a steering wheel 13 for steering the front wheels 2, and brake devices 18 and 19 are provided for the front wheels 2 and the rear wheels 3, respectively. And brake devices 18, 19
Are connected by wires 16 and 17.

The wires 16, 17 are pulled by pulling the brake levers 14, 15, and the wires 16, 17 are pulled.
The front and rear brake devices 18 and 19 are respectively operated by 17. Further, a brake switch 20 is provided in the middle of the wires 16 and 17, and the mechanism is such that energization of the motor 8 is stopped when the brake levers 14 and 15 are operated.

A battery section 22 serving as a power supply for the motor 8 is mounted on the frame 4 on the rear wheel 3. The battery section 22 includes a battery case 23 slidably attached to the frame 4 and a single-type rechargeable battery housed in the battery case 23. The power supply voltage is approximately 24 volts. Note that the battery case 23 may be provided in another place of the frame 4.

Next, the disc-shaped casing 5 will be described with reference to FIGS. FIG. 2 is a front view showing the configuration of the disc-shaped casing 5 shown in FIG. 1, and in the drawing, reference numeral 7 denotes a fixed casing fixed to the electric bicycle main body.

The fixed casing 7 includes a control board (not shown) composed of a control board and a heat sink, a motor 8, a first pulley for transmitting the output of an output shaft 24 of the motor 8, and a pulley set 25 of a second pulley. A speed reduction mechanism 26 composed of three pulley groups of the last stage pulley 28, and a transmission belt 27 connecting between the pulleys of the speed reduction mechanism 26 and the last stage pulley 28 are arranged.

The last-stage pulley 28 is fixed to the rotary casing 6. When the motor 8 rotates, the portion from the output shaft 24 of the motor 8 to the last-stage pulley 28 is rotated by the transmission belt 27, and is decelerated to a final stage. The rotation side casing 6 rotates together with the pulley 28.

The second pulley 28 connected to the last pulley 28
A one-way clutch (not shown) is interposed in the smaller pulley so that the motor 8 is not turned when a force from the pedal is applied, that is, the pedal is light. 29 is a rear wheel axle.

FIG. 3 shows a motor 8 in the disk-shaped casing 5.
It is a front view which shows the arrangement state of a stator, 30 is a stator, 40
Is a magnet.

[0017]

In such an electric bicycle, it is required to reduce the size and weight of the battery, to make full use of the capacity of the battery, and to enhance the compatibility of the battery. ing. In contrast,
Conventionally, there is known a control in which the voltage of a battery is monitored and the power supply to a motor is stopped when the voltage drops below a predetermined value, for example, 15 volts.

However, in this control, when the remaining amount of the battery becomes equal to or less than a predetermined value, the power supply to the motor is stopped, and the assist force is suddenly lost, so that there is a problem that the riding comfort is extremely poor. . Further, since the driving of the motor is stopped when the current and voltage values reach predetermined values, it has been impossible to use the battery to the maximum extent.

Accordingly, the present invention provides a compatible battery control system for an electric bicycle that has a good ride comfort, uses up the battery sufficiently, and uses batteries of different capacities by using up the battery sufficiently. Is what you do.

[0020]

According to a first aspect of the present invention, there is provided an electric vehicle battery control system comprising: a motor; and a current control circuit for inputting a battery voltage and a detection value of a current detection circuit. The current control circuit has a battery end voltage-current standard value, and is configured to control a current value so as not to fall below the standard value.

Thus, the capacity of the battery can be fully utilized by using up the battery sufficiently so as not to impair the life of the battery.

According to a second aspect of the present invention, there is provided an electric vehicle having a motor and a pulse width modulation type current control circuit for inputting a battery voltage and a detection value of a current detection circuit. The pulse width modulation type current control circuit has a battery cut-off voltage-current standard value, and is configured to control the current value so as not to fall below that value.

As a result, since the motor is driven while gradually reducing the current, the driving of the motor is not suddenly stopped, so that the riding comfort is good, and the capacity of the battery is fully used up without impairing the life of the battery. Fully available.

According to a third aspect of the present invention, there is provided an electric vehicle battery control system comprising: a motor; and a current control circuit or a pulse width modulation type current control circuit for inputting a battery voltage and a detection value of a current detection circuit. In the vehicle, each of the current control circuits has a battery cut-off voltage-current standard value, and controls the current value so as not to fall below that value. In the case where the battery is selected and mounted, the control is performed in accordance with the final voltage-current standard value of the large capacity battery.

As a result, since the motor is driven while gradually reducing the current, the driving of the motor is not suddenly lost, so that the riding comfort is good, and the capacity of the battery is fully used up without impairing the life of the battery. The battery can be used sufficiently, and a plurality of types (capacity) of batteries can be used as the battery for driving the electric bicycle without being limited to one type, and the motor control circuit can be used as it is.

According to a fourth aspect of the present invention, there is provided an electric vehicle battery control system comprising: a motor; and a current control circuit or a pulse width modulation type current control circuit for inputting a battery voltage and a detection value of a current detection circuit. In a car, each of the current control circuits has a battery cut-off voltage-current standard value, and usually controls a current value so as not to fall below that value. Is configured to stop energization.

[0027] Thus, by fully using the battery without impairing the life of the battery, the capacity of the battery can be fully utilized.

According to a fifth aspect of the present invention, there is provided an electric vehicle battery control system comprising: a motor; and a current control circuit or a pulse width modulation type current control circuit for inputting a battery voltage and a detection value of a current detection circuit. In the vehicle, each of the current control circuits has a battery cut-off voltage-current standard value, and usually controls a current value so as not to fall below that value. When the battery is selected and mounted, it is characterized in that the power supply to the motor is stopped when the standard voltage-current standard value of the large capacity battery falls below the standard value.

As a result, even if a plurality of types (capacity) of batteries are used as the driving battery for the electric bicycle and not limited to one type, the battery can be fully used without deteriorating the life of the battery, and the capacity of the battery can be improved. Is fully available.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described based on an embodiment with reference to the drawings. FIG. 4 shows a configuration diagram of a motor drive circuit of the electric bicycle of the present invention.

In FIG. 4, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals.
22 is a battery, 31 is a microcomputer, 32 is a constant voltage circuit,
Reference numeral 33 denotes an FET drive circuit, reference numeral 34 denotes an FET element, and reference numeral 35 denotes a torque detection circuit. The resistors R1 and R2 detect a battery voltage, and the resistor R3 detects a current.

The microcomputer 31 is supplied with a voltage obtained by stabilizing the voltage of the battery 22 by the constant voltage circuit 32, and receives a battery voltage, a current signal, and a motor torque signal from the torque detection circuit 35.

In the drive circuit thus constructed, the microcomputer 31 normally outputs a torque signal required as an output of the motor at a ratio corresponding to the input torque from the torque detection circuit 35 and the vehicle speed of the bicycle from its internal memory. Based on the read torque signal, the FET drive circuit 33 is pulse width-modulated based on the torque signal to control the FET element 34, thereby controlling the drive of the assist motor 8.

Generally, the relationship between the discharge end voltage V and the current I depends on the capacity of the battery as shown in FIG. That is, for example, the VI of a battery having a capacity of 5.0 Ah
The characteristics are as shown by a straight line A, and the VI characteristics of a battery having a capacity of 2.5 Ah are as shown by a straight line B.

Therefore, the usable range must be above the straight lines A and B so as not to impair the life of the battery. On the other hand, conventionally, when a 24 volt battery is used, the battery voltage is monitored, and when the voltage drops below 15 volts, for example, the power supply to the motor is stopped.

However, in this method, it is impossible to make full use of the capacity of the battery. Therefore, according to the driving method of the present invention, the voltage V− shown in FIG.
The current I standard value is stored, and the resistance R
The battery voltage is detected by R1, R2, and the current is detected by the resistor R3 and input to the microcomputer 31 so that the voltage and the current become 5.0.
If it is above the standard value of Ah, that is, above the straight line A, FET
The pulse width modulation of the drive circuit 33 is controlled with a normal duty ratio.

Once the remaining battery power becomes low and reaches 5.0 A
When h becomes a standard value or less, the duty ratio is reduced by a predetermined value a (for example, 10%) to control the FET drive circuit 33 to supply the reduced current to the motor.

As a result, the motor current decreases, and the battery voltage tries to return to the original level, and therefore becomes larger than the 5Ah straight line A as indicated by the arrow in FIG.
Then, further driving is performed in this state, and the 5.0 Ah straight line A
If it is lower than the lower limit, the duty ratio of the FET drive circuit 33 is further reduced by a to reduce the motor current and drive.

If the voltage is not recovered above the 5.0 Ah straight line A even if the duty ratio is reduced by repeating the control as described above, the battery power is turned off and the driving of the assist motor is stopped.

In the above example, the description has been made on the assumption that the duty ratio is controlled by using the FET drive circuit that performs pulse width modulation.
Other means may be used as long as the means controls the motor so as to reduce the drive current to the motor when it falls below the 0Ah straight line A.

It is convenient for the user in terms of compatibility that a plurality of types (capacity) of batteries can be used as the battery for driving the electric bicycle without being limited to one type. Therefore, the battery capacity is not limited to that of 5.0 Ah, but may be 2.5 Ah.
Even when using a battery of Ah capacity, 2.
The voltage V-current I standard value of the 5 Ah battery is 5.0 Ah
, The drive circuit of the assist motor uses a battery with a battery capacity of 5.0 Ah as it is, and the voltage V-current I standard value of the battery of 5.0 Ah is used even for a battery of 2.5 Ah. , The same control as described above can be performed.

By controlling in this manner, the motor drive does not suddenly stop, and since the drive is performed while the current is gradually reduced, the riding comfort is good and the battery can be used effectively to the end.

Next, the control flow of the present invention will be described with reference to FIG. When the control is started, the current value of the motor detected in step 61 is input to the microcomputer. Similarly, the voltage value of the battery detected in step 62 is input to the microcomputer.

Next, at step 63, it is determined whether the input current and voltage values are less than 5.0 lines from the voltage V-current I standard value shown in FIG. It is determined whether or not. If it does not exist below the 5.0 line, that is, if it exists above the 5.0 line, the process proceeds to step 64, and the control of the FET drive circuit is continued with the current duty D to drive the motor.

If the input current and voltage values are less than 5.0 lines, the duty D is set to Da at step 65, and the FET drive is performed at the changed duty D at step 66. Controls the circuit and drives the motor.

Again, in step 67, the current and voltage values are input, and in step 68, it is determined whether the current value is less than 5.0 lines. If it does not exist below the 5.0 line, that is, if it exists above the 5.0 line, the process returns to step 61 and the same operation is repeated.

If the input current and voltage values are less than 5.0 lines, the process proceeds to step 69, where it is determined whether or not the duty D = 0. At 70, the operation of the motor is stopped. That is, the battery has been used effectively to the end.

If the duty D is not 0, the flow returns to step 65 to set the duty D = Da again and repeat the operation.

Although the above description has been made on the assumption that a battery with a battery capacity of 5.0 Ah is used, a battery with a different capacity, for example, a battery with a capacity of 2.0 Ah, has a capacity of 5.0 Ah stored in the memory of the microcomputer. Even if the same control is performed by using the voltage V-current I standard value of 0 Ah as it is, 2.5
Since the voltage V-current I standard value of the battery of Ah is below that of 5.0 Ah, the object of the present invention can be sufficiently achieved without any change in the control circuit.

[0050]

As described above, according to the present invention, since the motor is driven while the current is gradually reduced, the motor drive is not suddenly stopped, the riding comfort is good, and the battery is sufficiently charged so as not to impair the life of the battery. By using up, the capacity of the battery can be fully utilized.

Further, the battery for driving the electric vehicle is not limited to one type, and a plurality of types (capacities) of batteries can be used and the motor control circuit can be used as it is, so that the electric vehicle is convenient for the user in terms of compatibility. A battery control method can be provided.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an electric bicycle.

FIGS. 2A and 2B are a front view and a side view showing a configuration of a board-shaped casing.

FIG. 3 is a layout view of a motor on a board-shaped casing.

FIG. 4 is a configuration diagram of a motor control circuit of the present invention.

FIG. 5 is a characteristic diagram of a battery voltage V-current I standard value.

FIG. 6 is a control flowchart of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric bicycle main body 2 Front wheel 3 Rear wheel 4 Frame 5 Disc-shaped casing 6 Rotation side casing 7 Fixed side casing 8 Motor 9 Electric drive unit 10 Human power drive unit 11 Pedal 12 Chain 13 Handle 14, 15 Brake lever 16, 17 Wire 18, Reference Signs List 19 brake device 20 brake switch 21 saddle 22 battery unit 23 battery case 24 motor output shaft 25 pulley set 26 reduction mechanism 27 transmission belt 28 last stage pulley 29 rear wheel axle 30 stator 31 microcomputer 32 constant voltage circuit 33 FET drive circuit 34 FET Element 35 Torque detection circuit

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Toshihiro Matsumoto 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Yoshihiko Maeda 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Kazuhisa Matsumoto 2-5-5 Keihan Hondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (5)

[Claims] 1. An electric vehicle having a motor and a current control circuit for inputting a battery voltage and a detection value of a current detection circuit, wherein the current control circuit has a battery end voltage-current standard value, and A battery control method for an electric vehicle, characterized in that a current value is controlled so as not to fall below a threshold value. 2. The battery control system according to claim 1, wherein the current control circuit is of a pulse width modulation control type. 3. The method according to claim 1, wherein when a battery having an arbitrary capacity is selected from a plurality of batteries having different capacities, the battery is controlled in accordance with a standard voltage-current standard value of a battery having a large capacity. A battery control system for an electric vehicle according to claim 2. 4. The battery control system for an electric vehicle according to claim 1, wherein the power supply to the motor is stopped when the voltage falls below a final voltage-current standard value. 5. The battery for an electric vehicle according to claim 3, wherein when the battery is selected and installed, the power supply to the motor is stopped when the battery voltage falls below a final voltage-current standard value of the battery having a large capacity. control method.