JPH0549101A - Power supply protective circuit for vehicle - Google Patents

Abstract

PURPOSE:To prevent deadlock at the time of starting/traveling by connecting a first inverter between a battery and an electric rotating machine being driven through an internal-combustion engine and further connecting a second inverter between the battery and a load and stopping the operation of the second inverter when the battery voltage drops below a predetermined level. CONSTITUTION:An AC three-phase electric rotating machine 3 being driven through an internal-combustion engine is connected with a battery 8 through a first inverter circuit 61, an electric brake circuit 64, a smoothing capacitor 63 and a chopper circuit 62. Furthermore, the battery 8 is connected through a controller 20 with a second chopper circuit 91, a smoothing capacitor 92 and a second inverter circuit 93 in order to drive a three-phase motor 15. When a voltmeter buit in the controller 20 detects the terminal voltage of the battery 8 lower than a predetermined level, a signal is delivered in order to stop the operation of the second chopper circuit 91 and the second inverter circuit 93. Consequently, the battery 8 is protected against overdischarge resulting in prevension of deadlock at the time of starting/traveling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle power source protection circuit capable of preventing an overload of a DC power source for supplying power to a load such as a refrigerator mounted on a vehicle using an internal combustion engine-electric hybrid system.

[0002]

2. Description of the Related Art In this type of internal combustion engine-electric hybrid system, a thin three-phase AC rotary machine is built in a flywheel housing of a large diesel engine, and the operation of the three-phase AC rotary machine is controlled by an inverter device. As a result, the braking energy is regenerated as electricity or electric power is generated as an alternator, and the direct current power source such as a battery is charged by the electric power, and when the vehicle starts and accelerates, the direct current power source supplies power to the three-phase alternating current rotating machine. Has been proposed by the same applicant as a device adapted to assist the torque of a diesel engine by supplying the electric power to the motor and operating it as an electric motor.

There is provided a vehicle equipped with such a system in which a power load such as a refrigerator is mounted.

FIG. 3 is a diagram showing a diesel-electric hybrid system including the electric load. In FIG. 3, a large diesel engine 1 has a flywheel housing 2 in which a thin three-phase AC rotating machine 3 is built. A transmission 4 is provided at the rear of the flywheel housing 2. A rotation sensor 5 is provided on the rotation shaft of the diesel engine 1. The three-phase AC rotating machine 3 is connected to a power converter 6 including a first inverter circuit. A resistor 7 for braking energy consumption is connected to the power converter 6. Further, a battery 8 which is a DC power source and a second power conversion device 9 including a second inverter circuit are connected to the electric terminals of the power conversion device 6. Further, the rotation detection signal from the rotation sensor 5, the signal from the starter switch 10, the signal from the retarder adjusting lever 11, and the accelerator opening signal from the accelerator sensor 12 are input to the power converter 6. The accelerator opening signal of the accelerator sensor 12 is input to the electronic governor computer 13, and the fuel injection pump 14 is driven by the control of the electronic governor computer 13. In addition, AC power is supplied from the second power conversion device 9 including the second inverter circuit to the AC motor 15 that drives the refrigerator or the like.

In the system having the above-mentioned structure, when the system is started, the power converter 6 which receives the signal from the starter switch 10 operates the three-phase AC rotating machine 3 as a starter. When the vehicle starts and accelerates, the accelerator sensor 12
The power converter 6 that receives the signal from the three-phase AC rotating machine 3
Is operated as a torque assist motor. When the vehicle is braked, the inverter 6 that receives the signal from the retarder adjusting lever 11 operates the three-phase AC rotating machine 3 as a retarder (electric brake). At this time, when the regenerated energy is excessive, the braking energy is consumed by the resistor 7. The second power converter 9 including the second inverter circuit converts the DC power from the battery 8 into AC power and supplies the AC power to the AC motor 15. As a result, the electric motor 15 rotationally drives the refrigerator or the like.

[0006]

However, in a vehicle equipped with a power load such as a refrigerator as described above, the second power converter 9 simply converts DC power into AC power, and the electric motor 15 is used. However, even if the battery 8 is discharged, the electric power is supplied to the electric motor 15 and the battery 8 is over-discharged. Since the battery 8 also serves as a 24 [V] power source used by a general automobile,
The battery 8 is over-discharged, which causes the inconvenience that the electric power of 24 [V] cannot be supplied, and as a result, there is a drawback that the vehicle cannot be started or traveled.

Therefore, an object of the present invention is to provide a vehicle power source protection circuit capable of protecting a DC power source capable of storing and discharging electric power.

[0008]

The vehicle power supply protection circuit of the present invention is capable of storing DC power and discharging the stored DC power, as well as a rotating machine connected to the main shaft of an internal combustion engine that drives the axle of the vehicle. A DC power source, a first inverter circuit that supplies AC power from the DC power source to the rotating machine, and regenerates generated power from the rotating machine to the DC power source, and supplies AC power to the load from the DC power source. A second inverter circuit for controlling the voltage of the DC power supply, and abnormal time control means for stopping the operation of the second inverter circuit when the voltage becomes equal to or lower than a reference value. .

[0009]

In the above vehicle power supply protection circuit, the abnormal time control means takes in the voltage of the DC power supply and monitors it, and when the voltage becomes equal to or lower than the reference value, outputs the inverter operation stop signal to the second inverter. Output to the circuit. As a result, the second inverter circuit stops the inverter operation. Therefore, the discharge state of the DC power supply can be prevented by setting the reference voltage to a value that does not cause the discharge state of the DC power supply.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments of the accompanying drawings.

FIG. 1 is a circuit diagram showing an electric circuit of a system including an embodiment of a vehicle power source protection circuit of the present invention.

In FIG. 1, an electric terminal of the three-phase AC rotating machine 3 is connected to a battery 8 which is a DC power source via a power converter 6. This power conversion device 6 can supply the generated power from the three-phase AC rotary machine 3 to the battery 8 and conversely can supply the power from the battery 8 to the three-phase AC rotary machine 3, and can also resist the generated power during electric braking. It is configured so that it can be consumed by the device 7, and includes a first inverter circuit 61, a first chopper circuit 62, a smoothing capacitor 63, and an electric brake circuit 64.

The first inverter circuit 61 is configured to operate the three-phase AC rotating machine 3 as a generator or an electric motor by controlling the ignition timing of a switching element (not shown). In addition, the first inverter circuit 6
Three-phase AC rotating machine 3 is connected to the AC terminal of 1,
A first chopper circuit 62, a smoothing capacitor 63 and an electric brake circuit 64 are connected to the DC terminal of the first inverter circuit 61. First chopper circuit 62
Is a switching transistor 62Q, a bypass diode 63Da connected in parallel to the collector and emitter of the transistor 62Q with opposite polarities, and a rectifying coil 63L.
And a flywheel diode 63Db. The first chopper circuit 62 charges the battery 8 by the action of the rectifying coil 62L and the diode 62Db after switching the supplied electric power by the switching transistor 62Q, or supplies the electric power from the battery 8 via the bypass diode 63Da. The circuit is configured so as to be supplied to one inverter circuit 61. The electric brake circuit 64 includes a parallel circuit including a switching transistor 64Q and a diode 64D connected to the switching transistor 64Q in reverse polarity, and a resistor 7 connected in series to the parallel circuit, and turns on the switching element 64Q to turn the resistor 7 The electric brake is applied by consuming electric power.

The second power converter 9 includes a second chopper circuit 91 for switching the DC power from the battery 8 to boost and output the DC power, and a smoothing circuit for smoothing the output from the second chopper circuit 91. It includes a capacitor 92 and a second inverter circuit 93 which converts the DC power stored in the smoothing capacitor 92 into AC power and supplies the AC power to the AC motor 15 as a load. A control device 20 is connected to the second power conversion device 9. The control device 20 is
The circuit is configured to monitor the voltage of the battery 8 and stop the operations of the second chopper circuit 91 and the second inverter circuit 93 when the voltage becomes a reference value or less.

The second chopper circuit 91 includes a boosting coil 91L, a switching transistor 91Q, a protection diode 91Da for the transistor 91Q, and a reverse current blocking diode 91Db. The voltage is boosted by the action of 91L and the backflow prevention diode 91Db to store high-voltage DC power in the smoothing capacitor 92. The control device 20 is composed of an analog / digital converter (not shown) that digitizes the voltage of the battery 8 and a computer device that can process digital data from the analog / digital converter and output a switching stop signal. do it.

Next, the operation of the embodiment configured as described above will be described with reference to FIGS. Here, FIG.
3 is a flowchart for explaining the operation of the control device 20.

The electric power generated by the three-phase AC rotating machine 3 is switched by the first inverter circuit 61 and stored in the smoothing capacitor 63 in a smooth manner. The electric power stored in the smoothing capacitor 63 is switched by the switching transistor 62Q, and then the battery 8 is charged by the action of the rectifying coil 62L and the diode 62Db.

The electric power from the battery 8 is supplied to the first inverter circuit 61 via the bypass diode 63Da.
Supply to. The first inverter circuit 61 converts the three-phase AC rotating machine 3 into an AC electric motor as needed to assist the diesel engine 1 with torque. The surplus power and the like are consumed by the resistor 7 by turning on the switching 64Q of the electric brake circuit 64.

By the way, when the battery 8 is no longer charged due to a failure of the three-phase AC rotating machine 3, the first inverter circuit 61, the first chopper circuit 62, etc., the AC motor 15, which is a power load, is transferred from the battery 8 to the AC motor 15. If the power is continuously supplied, the battery 8 will be in an over-discharged state. Therefore, the control device 20 first takes in the voltage of the battery 8 into the computer device via an analog-digital converter (not shown) (step 100). Then, the control device 20
Is a signal V for stopping the operations of the second chopper circuit 91 and the second inverter circuit 93 when the voltage of the taken-in battery 8 becomes equal to or lower than the reference value (step 101).
Output c (step 102). As a result, the operations of the second chopper circuit 91 and the second inverter circuit 93 are stopped (step 103).

When the taken-in voltage of the battery 8 is equal to or higher than the reference value (step 101), the control device 20 continues the normal switching operation without outputting the signal Vc, takes in the voltage of the battery 8, and Is repeated (steps 100 to 10).
1).

As described above, in this embodiment, the control device 20 detects that the voltage value of the battery 8 which is a DC power source decreases in accordance with the discharge state, and when the detected voltage becomes a certain value or less, By stopping the operation of the second inverter circuit 93, the battery 8 is prevented from being over-discharged and the vehicle cannot be started or run.

[0022]

As described above, according to the present invention, the voltage of the DC power supply is monitored, and when it falls below a certain value, the operation of the second inverter circuit for supplying power to the power load is stopped. By doing so, it is possible to prevent the DC power supply from being discharged and prevent the vehicle from being unable to start or run.

[Brief description of drawings]

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

FIG. 2 is a flow chart for explaining the operation of the embodiment of the present invention.

FIG. 3 is a configuration diagram showing a conventional internal combustion engine-electric hybrid system.

[Explanation of symbols]

 1 Diesel Engine 3 Three-Phase AC Rotating Machine 6 Inverter 7 Resistor 8 Battery (DC Power Supply) 9 Second Power Converter 15 Three-Phase Motor (Power Load) 20 Controller (Abnormal State Control Means) 61 First Inverter Circuit 62 First Chopper Circuit 91 Second Chopper Circuit 93 Second Inverter Circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Furudo 3-1-1 Hinodai, Hino-shi, Tokyo Hino Motors Co., Ltd. Hino factory

Claims (1)

[Claims] 1. A rotating machine connected to a main shaft of an internal combustion engine for driving an axle of a vehicle, a DC power supply capable of storing DC power and discharging the stored DC power, and AC power from the DC power supply to the rotating machine. And a second inverter circuit that supplies AC power to the load from the DC power supply, a first inverter circuit that regenerates the generated power from the rotating machine to the DC power supply, and a voltage of the DC power supply. A power supply protection circuit for a vehicle, comprising: an abnormality control means for monitoring and stopping the operation of the second inverter circuit when the voltage becomes equal to or lower than a reference value.