JPH09266635A - Electric motor car controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely inform a driver that the depth of the discharging of a battery has amounted to the specified position or more, and also, prevent the discharging from advancing above it when the depth of discharging amounts to the limit value. SOLUTION: A microcomputer 25 gets the temperature Tb of a battery 10 by temperature detectors 24A to 24E, in case that the discharging current Ib of the battery 10 detected by a current detector 23, and besides it makes an alarm lamp 27 perform the information when it judges that the depth of the discharging of the battery 10 has reached 90%, referring to the terminal voltage Vb of the battery 10 detected by the voltage detector 22d, and also it gives a control signal to an inverter 12 and controls this so at to gradually lower the maximum output of an induction motor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle controller for controlling the drive of a drive motor by controlling an inverter circuit that converts a DC voltage of a battery into an AC voltage.

[0002]

2. Description of the Related Art An electric vehicle converts a DC voltage of a battery into an AC voltage by an inverter circuit or the like and supplies the AC voltage to a drive motor such as a brushless motor or an induction motor. The drive motor drives a transmission, a differential gear and an axle. It is configured to drive by driving wheels via the wheels. In this case, a rechargeable lead acid battery or the like is used as the battery.

Since the battery discharges as the electric vehicle is driven, its capacity gradually decreases. In order to inform the driver of the remaining capacity of this battery, conventionally,
For example, as disclosed in Japanese Patent Laid-Open No. 61-135335, the terminal voltage of a battery is detected, and the terminal voltage is compared with a plurality of preset reference voltages to calculate the remaining capacity, The remaining capacity was displayed on the remaining capacity meter installed in the combination meter in the driver's seat.

Further, as disclosed in Japanese Patent Laid-Open No. 62-55576, the time during which the electrolyte temperature of the battery is above the upper limit value or below the lower limit value is integrated, and the integrated time reaches a predetermined value. Then, the warning device was operating.

In such a conventional technique, the driver is
When the decrease in the remaining capacity of the battery is recognized by looking at the remaining capacity meter or by noticing the warning of the warning device, the battery is charged.

[0006]

However, the driver continues to drive the electric vehicle without overlooking the remaining capacity meter and noticing the decrease of the remaining capacity of the battery, or even if the warning of the warning device is noticed. In this case, the battery may exceed the completely discharged state and become over-discharged, resulting in a problem that the life of the battery is shortened.

The present invention solves the above-mentioned problems, and an object of the present invention is to reliably notify the driver that the depth of discharge of a battery has reached a predetermined value or more, and when the depth of discharge reaches a limit value, An object of the present invention is to provide an electric vehicle control device that prevents further discharge.

[0008]

In order to achieve the above object, an electric vehicle control apparatus according to claim 1 is a battery mounted in an electric vehicle and a drive motor for converting a DC voltage of the battery into an AC voltage. Applied to the inverter circuit, voltage detection means for detecting the terminal voltage of the battery, current detection means for detecting the discharge current of the battery, notification means for informing the driver, and voltage detection means for detecting. The discharge depth of the battery is detected from the discharge current detected by the terminal voltage and current detection means, and when the discharge depth becomes equal to or greater than a predetermined value, the notification means is controlled to perform the notification operation and the drive motor Control means for controlling the inverter circuit so as to gradually reduce the maximum output of the inverter.

In this case, the control means may be configured to control the maximum output of the drive motor by gradually decreasing the upper limit of the maximum discharge current of the battery (claim 2). Further, the control means may be configured to control so as to decrease the maximum output of the drive motor by gradually decreasing the upper limit value of the voltage applied to the drive motor (claim 3).

Further, it is preferable that the temperature detection means for detecting the temperature of the battery is provided, and the control means is configured to correct the detection of the depth of discharge of the battery based on the temperature of the battery detected by the temperature detection means ( Claim 4). In addition, the control means may be configured to control the driving of the drive motor when the depth of discharge of the battery reaches the limit value (claim 5).

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. First, in FIG. 6 showing the overall configuration, an induction motor 2 is mounted as a drive motor in an electric vehicle 1. As shown in FIG. 1, the induction motor 2 includes a stator 3 having stator coils 3U, 3V and 3W having a plurality of phases, for example, three phases, and a rotor (not shown). The induction motor 2 drives the axles 7, 7 of the rear wheels 6, 6 via the transmission 4 and the differential gear 5. The axles 9, 9 of the front wheels 8, 8 of the electric vehicle 1 are not driven. A battery 10 such as a lead storage battery is mounted on the electric vehicle 1, and a DC voltage from the battery 10 is applied to the control device 11
An internal inverter circuit 12 (see FIG. 1), which will be described later, converts the AC voltage into an AC voltage and supplies the AC voltage to the induction motor 2.

In this case, as shown in FIG. 2, the battery 10 includes a plurality of, for example, 18 unit batteries (12V) 1
0a are arranged in 3 rows and 6 columns to form a rectangular parallelepiped shape, and 18 unit batteries 10a are electrically connected in series.

Now, regarding the specific configuration of the control device 11,
It will be described with reference to FIG. The inverter circuit 12 has six N
PN type transistors 13U, 13V, 13W and 14
U, 14V, and 14W are configured by connecting three-phase bridges, and flywheel diodes 15U, 15V, 15W and 16U, 16 are provided between the collector and the emitter, respectively.
V and 16 W are connected. The input terminals 17 and 18 of the inverter circuit 12 are connected to the DC buses 19 and 20.
Connected between the positive and negative terminals of the battery 10 via
The output terminals 21U, 21V and 21W are respectively connected to the respective terminals of the three-phase stator coils 3U, 3V and 3W of the induction motor 2. The stator coil 3
The other terminals of U, 3V and 3W are commonly connected.

The voltage detector 22 is connected between the DC buses 19 and 20 and detects the terminal voltage Vb of the battery 10. Further, the current detector 23 is arranged on the DC bus 20, and the discharge current I of the battery 10 is
It is designed to detect d. As shown in FIG. 2, the temperature detectors 24A to 24E, which are temperature detecting means, are installed at four corner portions and five central portions on the upper surface of the battery 10 having a rectangular parallelepiped shape. The temperature of each part of the battery 10 is detected.

A microcomputer (hereinafter, referred to as a microcomputer) 25, which is a control means, has its input terminals connected to the output terminals of the voltage detector 22, the current detector 23, and the temperature detectors 24A to 24E. The output terminal of the microcomputer 25 is connected to each input terminal of the photocoupler type gate drive circuit 26, and operates as described later. Each output terminal of the gate drive circuit 26 has six transistors 13U, 13V, 13W and 14U, 14V, 14W that form the inverter circuit 12.
Are connected to the base (gate) of each. In addition, the output terminal of the microcomputer 25 is provided with a warning lamp 27 as a notification means.
Is connected to the input terminal of This warning lamp 27
It is arranged on the combination panel in the driver's seat of the electric vehicle 1.

Next, the operation of this embodiment will be described with reference to FIGS. First, the operation of the electric vehicle 1 during traveling will be described. That is, the microcomputer 25 outputs an energization timing signal to the transistors 13U to 13W and 14U to 14W of the inverter circuit 12 and supplies the energization timing signal to the gate drive circuit 26, and the gate drive circuit 26 responds to the energization timing signal by the transistors 13U to 13W. And the base signals of 14U to 14W are applied to the bases in a predetermined order so that their transistors
And 14U to 14W are turned on / off. As a result, the inverter circuit 12 creates an AC voltage from the DC voltage of the battery 10 and gives it to the induction motor 2, and the induction motor 2 rotates and the electric vehicle 1 runs.

In this case, the microcomputer 25 PWM-controls the transistors 13U to 13W and 14U to 14W according to the opening degree of an accelerator (not shown), and thus controls the rotation speed of the induction motor 2. In addition, the transmission 4 is
It has a clutch function and an automatic speed change function, and controls the differential gear 5 so as to give optimum torque to the wheels 6 and 6.

Next, the detection of the depth of discharge of the battery 10 will be described. The battery 10 has, for example, an output voltage 216.
It is assumed that V and capacity are 40 Ah. FIG. 3 shows the relationship between the discharge capacity (discharged capacity) and the terminal voltage when the battery 10 has different temperatures. That is, the terminal voltage Vb when the battery 10 is fully charged (the discharge capacity is 0 Ah) is around 225 V, and the terminal voltage Vb decreases as the discharge progresses (the discharge capacity increases). The terminal voltage Vb of the battery 10 is approximately 180V.
The battery 10 is in a completely discharged state at the time when the battery capacity drops to 0. Therefore, the discharge capacity reaches about 40 Ah at that time.

The discharge depth, which expresses the degree of discharge depth of the battery 10 as a percentage, is 0% when the battery 10 is fully charged (voltage 225 V, discharge capacity 0 Ah), and complete discharge (voltage 180 V, discharge capacity 40 Ah). In case of 100%
Is defined.

FIG. 4 shows temperature-voltage characteristics of the battery 10 when the depth of discharge is 90% as a predetermined value when the battery 10 is discharging at 13A. The microcomputer 25 stores the temperature-voltage characteristics in the discharge depth of 90% to 100% of the battery 10 in the internal ROM as a data table.

While the electric vehicle 1 is running,
The microcomputer 25 uses the battery 1 detected by the current detector 23.
When the discharge current Ib of 0 indicates 13 A, the battery 1
When the terminal voltage Vb of 0 and the temperature Tb of the battery 10 are obtained by referring to the voltage detector 22 and the temperature detectors 24A to 24E, the value of the terminal voltage Vb at the temperature Tb is 90% of the discharge depth stored in the ROM. It is determined whether the depth of discharge of the battery 10 has reached 90% by comparing with the value of the data table of. The temperature Tb of the battery 10
Is the battery 1 detected by the temperature detectors 24A to 24E.
It is obtained by averaging the temperature of each part of 0.

When the microcomputer 25 judges that the depth of discharge of the battery 10 has reached 90%, the warning lamp 2
7 is turned on to notify the driver that the remaining capacity of the battery 10 is low.

If the driver does not notice the lighting of the warning lamp 27 and continues to drive the electric vehicle 1, the microcomputer 25, as shown in FIG.
The maximum output current of the induction motor 2 is controlled so as to gradually decrease the maximum output of the induction motor 2.

That is, when the depth of discharge of the battery 10 exceeds 90% and reaches 92.5%, the microcomputer 25 determines the ratio of the upper limit value of the maximum discharge current of the battery 10 to the upper limit value during normal operation. The PWM signal given to the inverter circuit 12 is controlled so as to be suppressed to 75% of 100%. As a result, the maximum speed or acceleration when driving the electric vehicle 1 decreases, so that the driver can also know from the operating state of the electric vehicle 1 that the remaining capacity of the battery 10 is low.

Then, as shown in FIG.
When the depth of discharge further reaches 95% and 97.5%, the microcomputer 25 adjusts the maximum discharge current rate to 5%.
When the depth of discharge is suppressed to 0% and 25% and the depth of discharge reaches 100%, that is, the state of complete discharge (limit value), the inverter circuit 12 is turned off to set the maximum discharge current rate to 0% and the electric vehicle 1 is stopped. This prevents the battery 10 from being discharged further and entering an over-discharged state.

As described above, according to this embodiment, when the discharge current Ib of the battery 10 detected by the current detector 23 is 13 A, the microcomputer 25 controls the temperature Tb of the battery 10 by the temperature detectors 24A to 24E. And
The terminal voltage Vb of the battery 10 detected by the voltage detector 22
If it is determined that the depth of discharge of the battery 10 has reached 90%, the warning lamp 27 is controlled to perform a notification operation, and the maximum output of the induction motor 2 is gradually reduced. To control the induction motor 2.

Therefore, the battery 10 based on the temperature Tb
Can be accurately detected, and even when the driver does not notice the notification operation of the warning lamp 27, it is clear that the remaining capacity of the battery 10 is small by changing the operating state of the electric vehicle 1. Since the notification can be given, the driver can be made to charge the battery 10 at an appropriate time.

Further, according to this embodiment, the microcomputer 25
In accordance with the depth of discharge of the battery 10 exceeding 90% and further increasing by 2.5%, the ratio of the upper limit value of the maximum discharge current of the battery 10 is set to 100% as the upper limit value during normal operation. So that it will decrease by 25%
Since the PWM signal applied to the inverter circuit 12 is controlled, the maximum speed and acceleration of the electric vehicle 1 can be gradually reduced, and the remaining capacity of the battery 10 can be effectively reduced to the driver. Can be notified.

Further, according to this embodiment, the microcomputer 25
Controls to stop driving the induction motor 2 when the depth of discharge of the battery 10 reaches 100%, so that the battery 10 can be prevented from being in an over-discharged state. The life can be extended.

The present invention is not limited to the embodiments described above and shown in the drawings, but the following modifications are possible. Although the depth of discharge is detected from the temperature and terminal voltage characteristics of the battery 10 when the discharge current Ib is 13 A, the discharge current Ib is not limited to 13 A and may be any value. Further, although the predetermined value is set to 90% of the depth of discharge, it may be appropriately changed. The number of small batteries forming the battery 10 is not limited to 18, and may be changed appropriately according to the required voltage. Further, the number of the temperature detectors 24 is not limited to five, and may be any number as long as an appropriate average temperature of the battery 10 can be obtained.

The battery 10 is not limited to a lead storage battery, but may be any secondary battery such as nickel cadmium, nickel manganese, or nickel hydride. Although the induction motor 2 is used as the drive motor, the two-phase motor,
A brushed DC motor, a brushless DC motor, a reluctance motor, or the like may be used. The depth of discharge of the battery 10 may be detected as a ratio of an integrated value of power consumption or an integrated value of only discharge current. The step of the depth of discharge for suppressing the maximum discharge current rate is not limited to 2.5% and may be changed as appropriate. Further, the rate of decreasing the maximum discharge current is not limited to 25% and may be changed as appropriate. When gradually decreasing the output of the induction motor 2, instead of suppressing the maximum discharge current rate, an output voltage detector that detects the output voltage of the inverter circuit 12 is provided to suppress the maximum output voltage rate. Is also good.

[0032]

Since the present invention is as described above,
The following effects are obtained. According to the electric vehicle control device of claim 1, the control means detects the depth of discharge of the battery from the terminal voltage detected by the voltage detection means and the discharge current detected by the current detection means, and the discharge depth is predetermined. When it exceeds a predetermined value, the notifying means is caused to perform the notifying operation and the inverter circuit is controlled so as to gradually reduce the maximum output of the motor. Therefore, specifically, the upper limit value of the maximum discharge current of the battery is gradually increased. (Claim 2) or the upper limit value of the voltage applied to the motor is gradually decreased (Claim 3), so that not only the notification of the notification means but also the operating state of the electric vehicle is changed. By doing so, it is possible to clearly inform the driver that the remaining capacity of the battery is low, and it is possible to charge the battery at an appropriate time.

According to the electric vehicle control device of the present invention, the control means corrects the detection of the depth of discharge of the battery based on the temperature of the battery detected by the temperature detection means. The discharge depth can be known, and the time when the notification operation is performed can be made more accurate.

According to another aspect of the electric vehicle control device of the present invention, the control means controls the driving of the motor to be stopped when the depth of discharge of the battery reaches a limit value. Can be prevented, and the life of the battery can be extended.

[Brief description of drawings]

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

FIG. 2 is a perspective view schematically showing a battery.

FIG. 3 is a diagram showing discharge characteristics of a battery.

FIG. 4 is a diagram showing temperature-voltage characteristics of a battery at a discharge depth of 90%.

FIG. 5 is a diagram showing a ratio for controlling a maximum discharge current rate of a battery.

FIG. 6 is an explanatory diagram of a configuration of an electric vehicle

[Explanation of symbols]

1 is an electric vehicle, 2 is an induction motor (driving motor), 10 is a battery, 11 is a control device, 12 is an inverter circuit, 22 is a voltage detector (voltage detection means), 23 is a current detector (current detection means), 24A to 24E are temperature detectors (temperature detecting means), 25 is a microcomputer (controlling means), and 27 is a warning lamp (notifying means).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H02M 7/48 9181-5H H02M 7/48 M H02P 7/63 302 H02P 7/63 302D (72) Inventor Masaki Hirata 991, Anada Town, Seto City, Aichi Prefecture, Toshiba Aichi Factory (72) Inventor, Seiji Kato, 3-3-22 Nakanoshima, Kita-ku, Osaka City, Osaka Prefecture Kansai Electric Power Co., Inc.

Claims (5)

[Claims] 1. A battery mounted on an electric vehicle, an inverter circuit for converting a DC voltage of the battery into an AC voltage and applying the AC voltage to a drive motor, a voltage detection unit for detecting a terminal voltage of the battery, and the battery. Current detection means for detecting the discharge current of the battery, notification means for notifying the driver of the driver, and the discharge voltage of the battery from the terminal voltage detected by the voltage detection means and the discharge current detected by the current detection means. When the depth of discharge is detected and becomes equal to or greater than a predetermined value, the notifying unit is controlled to perform the notifying operation, and the inverter circuit is controlled to gradually reduce the maximum output of the drive motor. And an electric vehicle control device. 2. The electric vehicle control apparatus according to claim 1, wherein the control means controls to gradually reduce the upper limit value of the maximum discharge current of the battery to reduce the maximum output of the drive motor. . 3. The electric vehicle control according to claim 1, wherein the control means controls so as to decrease the maximum output of the drive motor by gradually decreasing the upper limit value of the voltage applied to the drive motor. apparatus. 4. A temperature detection means for detecting the temperature of the battery is provided, and the control means corrects the detection of the depth of discharge of the battery based on the temperature of the battery detected by the temperature detection means. The electric vehicle control device according to any one of Items 1 to 3. 5. The electric vehicle control device according to claim 1, wherein the control means controls to stop driving the drive motor when the depth of discharge of the battery reaches a limit value. .