JP2001309574A - Charging system comprising a plurality of alternator for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve reduction in size and improvement in function of an alternator for vehicle. SOLUTION: An alternator for vehicle is allocated in separation for a low voltage side (1) and a high voltage side (2), and batteries (3, 4) corresponding to respective alternators for vehicle are also provided to use in common the power of both alternators.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging system provided with a vehicle alternator, and more particularly to a vehicle alternator charging system suitable as a vehicle power generator.

[0002]

2. Description of the Related Art There are the following known examples of conventional vehicle alternators. First, the first and second known examples are disclosed in
As described in JP-A-125964 and JP-A-61-155056, the first vehicle alternator is
There is disclosed a system in which a second vehicular AC generator is used as a power source for an electric power steering, which is used for 2V power generation. As a power source for the electric power steering, power is supplied only from the second vehicle alternator, and no battery is provided for the second vehicle alternator. As third and fourth known examples, JP-A-2-97236 and JP-A-3-97236
JP-A-183331 discloses a vehicle equipped with two units, a low-voltage-side vehicle AC generator and a high-voltage-side vehicle AC generator. Power is supplied to the low voltage side from the vehicle AC generator on the side. A fifth known example is disclosed in
Japanese Patent Application Publication No. 11727 discloses a configuration in which a vehicle alternator is one for low voltage or high voltage, and is capable of charging both a high voltage side load and a battery to which a low voltage side load is connected. ing. As a sixth known example, as described in Japanese Patent Application Laid-Open No. 6-62539, the output of one vehicle AC generator configured to rotate at a constant speed is a DC voltage output and an AC voltage output. There are three types of outputs: an AC voltage side output is configured to charge a low voltage side battery via a voltage conversion circuit, and a DC voltage output is directly connected to a high voltage side.

[0003]

In the above-mentioned prior art, in the first and second known examples, two vehicle AC generators are divided into a low-speed side and a high-speed side to supply power. Since there is no means for mutually supplying power, a vehicle alternator corresponding to each load is required, which leads to an increase in the size of each vehicle alternator. Further, in the third and fourth known examples, power can be supplied from the high voltage side to the low voltage side, but the configuration cannot cope with a shortage of power on the high voltage side. In the fifth known example, one type of vehicle alternator is configured to charge two kinds of voltages, and since the number of vehicle alternators is one, the physical size may be increased. Further, when one vehicle alternator fails, charging of both power sources is stopped. In the sixth known example, as in the fifth known example, one vehicle is used to generate two power supplies of a low voltage side power supply and a high voltage side power supply from a vehicle AC generator configured to be able to rotate at a constant speed. If the AC generator fails, neither system can be charged, and the vehicle cannot run.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle system that requires a low-voltage power supply and a high-voltage power supply so that one of the power supplies can charge the other power supply so that power can be mutually supplied. Is proposed.

[0005]

In order to achieve the above object, according to the present invention, a low-voltage side and a high-pressure side dedicated vehicle AC generator are provided, and batteries corresponding to the respective vehicle AC generators are provided. It is possible to exchange power from a low voltage to a high voltage side or vice versa, from a high voltage to a low voltage side. In addition, the present invention is realized by using a two-vehicle AC generator, a battery for storing the output of each vehicle, and a DC voltage conversion circuit capable of mutually exchanging power.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a vehicle power supply system using two vehicle alternators. The overall configuration will be described. The first vehicle alternator 1 is connected in parallel to a low voltage side 12 V battery 3,
Similarly, the electric loads 5 for 2 V are connected in parallel. At this time, the negative side of the 12 V battery 3 is connected to the ground potential of the electronic circuit system and to the vehicle body. Next, the second vehicular alternator 2 is connected in parallel with a 36 V battery 4 and a 36 V load circuit 6. The output of the first vehicle alternator 2 is connected to the output of the second vehicle alternator 2 via a DC voltage conversion circuit 7. The output of the second vehicle alternator 2 is connected to the output of the first vehicle alternator 1 via a DC voltage conversion circuit 8. Arrows in the figure indicate the moving direction of electric power.

[0007] The respective DC voltage conversion circuits 7 and 8
It converts the voltage on the input side to the voltage on the output side. In this embodiment, the DC voltage conversion circuit 7 corresponds to a booster circuit,
DC voltage conversion circuit 8 corresponds to a step-down circuit. Therefore, if one of the two DC voltage conversion circuits is operated, power can be supplied to loads having different voltages. In addition, the DC voltage conversion circuit 7 or the DC voltage circuit 8 is controlled so that only one of them operates, and therefore, if one circuit configuration has a function of performing step-up / step-down conversion, it may be used. good.

Next, the reason why two vehicle alternators are provided will be described. As in the conventional example, in the known example, one power source is generated by using one vehicle alternator, and the second voltage must be generated by using the voltage conversion circuit. Two types of power sources must be created for the vehicle alternator. For this reason, the power generation capacity of the vehicle alternator must be increased, and there is a disadvantage that the physical size of the vehicle alternator increases. In addition, if the physique is large, it lacks in-vehicle properties. Further, in this embodiment, the 36V power supply on the high voltage side is assumed to be a power supply used for a relatively large power supply, and is used for an electric catalyst, an auxiliary power motor, and the like. For example, taking an electrocatalyst as an example, when the electric power is required most, it is immediately after the start of the engine when the engine speed is almost equal to the idling speed. Since the pulley ratio of the conventional vehicle alternator is set to about 2.5 times the engine speed, the engine speed is assumed to be 800 r / min when idling and multiplied by 2.5 times. Then, it was necessary to supply the maximum power at 2000 r / min. As a result, he did not gain any physique.

According to the present invention, a plurality of vehicle alternators are operated independently in accordance with a required power supply, so that the on-board performance is taken into consideration and the output of each vehicle generator can be used by another power supply. It is configured via a DC voltage conversion circuit. Therefore, it goes without saying that each vehicle alternator can be made smaller, and the number of revolutions can be changed according to the load by setting the pulley ratio with the engine separately according to the load used. In addition, by providing a vehicle alternator for each power generation voltage, even if a trouble occurs in one vehicle alternator, it can be backed up by the remaining vehicle alternator and the buck-boost circuit. The worst can be avoided.

The above described low voltage side 12V power supply is a lamp,
A power supply supplied to loads such as electronic circuits.
The 6V power supply does not require continuous power such as a motor drive power supply having a relatively large power, an electrocatalyst, and molten glass, but consumes large power in a short time. Therefore, the power is always stored in the 36V battery 4 on the high voltage side, and when the power is needed, the battery 4 and the second vehicle alternator 2 are operated to supply the power. Further, when the power of the low voltage side 12V load is insufficient and cannot be covered by the power generation of the vehicle AC generator 1, the DC voltage conversion circuit 8 is operated to supply the power from the high voltage side to the low voltage side. . Regarding the operation of the DC voltage conversion circuit, ON / OFF of the operation is determined by detecting the battery terminal voltage on the supply side. Specific actions,
A case where a current is supplied from the high voltage side to the low voltage side vehicle AC generator 1 will be described. The generated voltage of the vehicle alternator 1 is about 14.5 V when there is no load,
When the current flowing through the battery 3 increases, the terminal voltage of the battery 3 decreases. If the voltage converter 8 is set to operate when the terminal voltage of the battery 3 on the supply side becomes, for example, 13.5 V or less, the first vehicle alternator 1
When power generation shortage occurs, power can be supplied from the high voltage side, and discharge of the low voltage side battery can be prevented. If the DC voltage conversion circuit 7 is set to operate when the battery terminal voltage on the opposite high voltage side becomes 40.5 V or less, the power generation of the second vehicle AC generator 2 becomes insufficient. Can supply electric power from the low voltage side to the high voltage side. Further, when the low voltage and the high voltage decrease at the same time, the stability of the control system is achieved by giving priority to the low voltage side power supply that supplies the power of the engine control unit that controls the engine. .

Next, a second embodiment will be described with reference to FIG. FIG. 2 shows a case where the high voltage side battery is omitted from the high voltage side load circuit 6. The overall configuration of FIG. 2 will be described. A 12V battery 3 and a 12V load 5 are connected in parallel to the low-voltage first vehicle alternator 1. The negative side of the battery 3 is grounded to the vehicle body and serves as a reference potential of the power supply. In the high-voltage side power supply circuit, a high-voltage load circuit 6 is connected to the output terminal of the second vehicle alternator 2, and the reference potential is the same as the low-voltage side reference potential described above. The DC voltage conversion circuit 7 has a configuration in which the booster circuit 7 is arranged so that the voltage can be converted from the low voltage side to the high voltage side and charged. As shown by arrows in the figure, the flow of electric power is in one direction from the low pressure side to the high pressure side.
The reason for this is that the power supply time is short due to the characteristics of the load used on the high voltage side. Even if a small load is applied to the low-voltage side battery 3, it is possible to reduce the size of the high-voltage side AC generator 2 for a vehicle. In this case, the field current of the vehicle alternator 2 on the high voltage side is supplied from the battery 3 on the low voltage side because there is no battery on the high voltage side. Further, the signal for determining the operation of the vehicle alternator 2 on the high voltage side operates according to the signal 10 from the engine control unit 9 (ECU). The engine control unit 9 detects the load request on the high pressure side and turns on and off the vehicle alternator 2 on the high pressure side. Further, the engine control unit 9 constantly monitors the terminal voltage of the 12V battery 3 so that the low-voltage battery 3 is not over-discharged (not shown).

As shown in FIG. 2, by operating the second vehicular alternator 2 only when power is supplied to the high-voltage load 6 that operates discontinuously, the power on the high-voltage side is increased. When there is no demand, the second vehicle alternator 2 is controlled to stop the power generation by a signal 10 from the engine control unit 9 so as not to generate the power. The DC voltage conversion circuit 7 detects the voltage on the output side. In this embodiment, the power supply on the high voltage side is assumed to be 36 V. 7 is turned on to supply power from the low voltage side to the high voltage side.

FIG. 3 illustrates the configuration of the vehicle alternator actually mounted on the engine in the first embodiment.

FIG. 3 shows a state in which the two vehicle alternators described with reference to FIG. 1 are connected via a crank pulley of the engine. The configuration will be described. The pulley 12 of the first automotive alternator 1 is connected to a crank pulley 13 of the engine 11 via a belt. The pulley ratio is set to about 2.5 times because the first vehicle alternator 1 always rotates to use it for low voltage. The pulley 14 of the second vehicle alternator 2 is connected to a crank pulley 15 of the engine 11 via a belt. The operation of the second vehicular alternator 2 is assumed to be performed only when the engine is started. Therefore, the pulley ratio is about four times larger than the pulley ratio of the first vehicular alternator 1. The number of rotations is set so that the output is sufficient even if the engine 11 is idling and rotating. As described above, the 12 V battery 3 on the low voltage side and the load circuit 5 on the low voltage side are connected to the load side of the first vehicle alternator 1. The 36 V battery 4 on the high voltage side and the high voltage side load circuit 6 are connected to the load side of the second vehicle alternator 2. A DC voltage conversion circuit 78 is arranged between the batteries, and the booster circuit or the step-down circuit is set to operate according to the terminal voltage of the battery. As described above, when both the low-voltage battery voltage and the high-voltage battery voltage become lower than the reference voltage, the low-voltage charging is prioritized.

FIG. 4 shows the DC voltage conversion circuit 7 described with reference to FIG.
8 shows a circuit configuration. The configuration will be described. 1 for low pressure
A smoothing capacitor 2 is connected between both terminals of the 2V battery 3.
2 are connected in parallel. The positive terminal of the capacitor 22 is connected to the reactor 21, and the other terminal is connected to the collector of the boosting transistor 23. The collector has a cathode of a step-up diode 24, an emitter of a step-down transistor, and a step-down diode 2.
6 is connected to the anode. The collector of the step-down transistor 25, the cathode of the step-down diode 26, the plus side of the smoothing capacitor 27, and the plus terminal of the high-voltage battery 4 are connected. The negative side of the battery 4 is connected to the negative side of the capacitor 27, the anode of the boost diode 24, the emitter of the boost transistor 23, the negative side of the capacitor 22, and the negative terminal of the low-voltage battery 3. The output of an AND circuit 28 is connected to the base of the boosting transistor 23, and a boost / step-down selection signal U / D for selecting step-up or step-down and a duty signal Ud at the time of step-up are connected to two inputs of the AND circuit 28. Have been. As mentioned earlier,
The step-down select signal U / D is also connected to the input side of the inverter circuit 30, and the output of the inverter circuit 30 is
It is connected to the input of D circuit 29. The other input of the AND circuit 29 is connected to the step-down duty signal Dd, and the output signal of the AND circuit 29 is connected to the base of the step-down transistor 25.

The operation of the above configuration will be described. First, the case of boosting the voltage from the low-voltage battery 3 to the high-voltage battery 4 will be described. In this case, the operation is performed when the terminal voltage of the battery 4 on the high voltage side becomes 40.5 V or less, and this voltage detection is performed by an engine control unit (not shown). When the voltage becomes lower than the above-mentioned value of 40.5 V, the boost / step-down select signal U / D is set to H in order to operate the booster circuit.
Level. Then, the boosting transistor 2 is set so that the terminal voltage of the step-down battery 4 becomes about 40.5 V.
3 determines the duty of the boost duty signal Ud applied to the base. In this case, since the step-up / step-down selection signal U / D of the AND circuit 29 is at the L level, the high-voltage side transistor 25 does not operate in the off state. Next, the operation at the time of step-down will be described. The step-down occurs when the power used by the low-voltage side load 5 becomes large with respect to the power generation amount of the low-voltage side vehicle alternator 1, and the terminal voltage of the low-voltage side battery 3 becomes 13.5 V. It operates when divided. In the voltage detection, the terminal voltage of the battery 3 on the low voltage side is detected by an engine control unit (not shown) as in the case of boosting, and when the voltage becomes lower than the reference voltage (13.5 V), a boost / step-down selection signal is output. U / D is set to L level output. Therefore, the output of the AND circuit 28 goes low, and the output signal of the AND circuit 29 goes high. Further, the step-down duty signal Dd is output from the engine control unit to the terminal voltage of the low-voltage side battery 3.
The duty is determined so as to be about 13.5V. In the above description, a transistor is used for the step-up / step-down switch. However, a similar function can be achieved by using a switching element such as a MOS-FET or IGBT. Further, the voltage detection level at which the booster circuit and the step-down circuit operate is 13.5 V in the case of a low voltage, and 3 times of 13.5 V in the high voltage side.
Although described as 5 V, this voltage may be slightly different. Further, the conversion voltage to be converted is 13.5 V in the case of a low voltage, and 40.5 V which is three times 13.5 V in the case of a high voltage.
However, this voltage value may be slightly increased. However, when the voltage is increased, it is necessary to provide the operating voltage with hysteresis.

FIG. 5 shows that the battery 4 is connected only to the low-voltage side vehicle alternator 1 shown in FIG. 2, and only the high-voltage side electric load is connected to the high-voltage side vehicle alternator 2. In this case, a booster circuit configuration for supplying power from the low voltage side to the high voltage side is shown. First, the configuration will be described. One terminal of a reactor 21 is connected in series to the positive side of the low voltage side battery 3. The other terminal of the reactor 21 is connected to the collector of the boosting transistor 23, the cathode of the diode 24, and the anode of the diode 26. The cathode of the diode 26 is connected to the positive side of the smoothing capacitor 27 and the positive side of the high-voltage battery 4. Side terminal is connected. The negative side of the battery 3 on the low voltage side is connected to the emitter of the transistor 23, the anode of the diode 24, the negative side of the capacitor 27, and the negative terminal of the battery 4 on the high voltage side. As described above, the boosting operation includes an operation unit such as an engine control unit, a comparator that can output a duty only when a detection voltage becomes smaller than a reference voltage set in advance by an analog circuit, and the like. The boosting duty of the transistor is determined by the used comparison circuit.

The feature of providing this step-up / step-down circuit is to reduce the size of the high-voltage side vehicle alternator 2 in a system on the premise that the load on the high-voltage side is used less frequently. When the load current on the high-voltage side, which is used less frequently, is insufficient, the power is supplied from the low-voltage side to achieve this.

In the above description, the case where two vehicle alternators are driven by one engine has been described.
In the case of a vehicle equipped with two engines, the low-voltage side vehicle alternator and the high-pressure side vehicle alternator can be driven by different engines. For example, buses, campers, and the like are examples of two engines.

Next, referring to FIG. 6, a description will be given of a structure in which the low-voltage side and high-voltage side batteries and the DC voltage conversion circuit are integrally formed to reduce the size. First, the configuration will be described. The low-voltage battery 3 and the high-voltage battery 4 are arranged inside the case 40. A DC voltage conversion circuit 78 is arranged between the batteries to convert the voltages of both batteries. The batteries are connected by wiring 41, and the terminals of both batteries are connected to the low-voltage side vehicle alternator 1 and the high-voltage side vehicle alternator 2. As shown in this figure, a compact arrangement can be realized by integrally configuring the battery and the DC voltage conversion circuit. As shown in the figure, the case 40 may be made of a plastic made of a heat insulating material, but may be shielded by a metal case in order to prevent switching noise from being emitted outside.

In the present invention, the ground level of the low voltage side and the ground level of the high voltage side are described as the same. However, for example, when the voltage on the high voltage side is a voltage of 36 V or more, it is better to insulate the high voltage side. In some cases. In that case, it can be realized by a configuration in which an insulating transformer is arranged in the booster circuit portion.

As described above, the object of the present invention is to realize the sharing of power on the low-voltage side and the high-voltage side, and to reduce the size of each vehicle alternator and the size of the battery. .

[0023]

As described above, according to the present invention, even if either the low-voltage side or the high-voltage side AC generator breaks down, one of the vehicle AC generators uses the low-voltage side and the high-voltage side. Since the power can be supplied to the vehicle, the vehicle can be safely driven to the repair shop using the minimum functions.

[Brief description of the drawings]

FIG. 1 is a configuration diagram for charging a voltage of two power sources by using two vehicle alternators to explain a first embodiment.

FIG. 2 is a system configuration diagram illustrating a second embodiment.

FIG. 3 is a layout diagram of an engine and a vehicle alternator.

FIG. 4 is an explanatory diagram of a step-up / step-down circuit according to the first embodiment;

FIG. 5 is an explanatory diagram of a booster circuit according to a second embodiment.

FIG. 6 is a configuration diagram in which a battery and a voltage conversion circuit are integrally disposed in a case.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... AC generator for low voltage side vehicles, 2 ... AC generator for high voltage side vehicles, 3 ... Low voltage side battery, 4 ... High voltage side battery,
5: low voltage side load, 6: high voltage side load, 7: DC voltage conversion circuit (step-up side), 8: DC voltage conversion circuit (step-down side), 9 ...
Engine control unit, 10 start signal, 11
... Engine, 12, 14 ... Pulley, 13,15 ... Crank pulley, 16 ... Excitation power supply, 21 ... Reactor, 2
2, 27 ... capacitor, 23, 25 ... transistor, 2
4, 26 ... diode, 28, 29 ... AND circuit, 30
... Inverter circuit, Ud ... Step-up duty signal, Dd ...
Step-down duty signal, U / D ... step-up / step-down select signal, 4
0: case, 41: wiring, 78: step-up / step-down DC voltage conversion circuit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuo Nishihama 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Kazuo Tahara 7, Omikamachi, Hitachi City, Ibaraki Prefecture No. 1-1 Inside Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Masami Takano 2520 Oji Takaba, Hitachinaka-shi, Ibaraki F-term in Hitachi Automotive Equipment Group 5G060 AA20 BA01 BA08 DA01 DB02 DB08 5H590 AA01 AA03 CA23 CB10 CD10 CE05 FB01 FC12 FC17 FC22 HA02

Claims (8)

[Claims] A rotor that generates a rotating magnetic field; and a stator that is disposed at a predetermined distance from the rotor and has a stator winding that generates an AC voltage by magnetization of the rotor. Wherein at least two or more vehicular AC generators each including a rectifier circuit for converting the AC voltage into a DC voltage are provided, and a step-up / step-down circuit capable of converting the voltage of both vehicular AC generators is provided between the power supplies. A charging system including a plurality of vehicle alternators. 2. The vehicle alternator according to claim 1, wherein the first vehicle alternator is operated continuously, and the second vehicle alternator operates discontinuously according to the load. A charging system equipped with multiple vehicle alternators. 3. A first vehicle alternator according to claim 1, wherein a battery is connected in parallel with the first vehicle alternator, and an output of the second vehicle alternator is directly connected to a load circuit. The field power of the vehicle alternator is supplied from a battery to which the first vehicle alternator is connected, and the output voltage of the first vehicle alternator is applied to the load circuit. A charging system comprising a plurality of vehicle alternators, wherein power is supplied to the second load circuit via a heater. 4. The charging system according to claim 3, wherein the start / stop signal is operated by a signal from an engine control unit. 5. The vehicle alternator according to claim 1, wherein the plurality of vehicle alternators are connected by a belt so as to rotate in conjunction with a crank pulley of the engine, and each of the vehicle alternators has an output voltage. A charging system comprising a plurality of vehicle alternators characterized by being different. 6. The output voltage of the second vehicle alternator is set to be higher than that of the first vehicle alternator in the first vehicle AC generator. A charging system having a plurality of vehicle alternators, wherein the crank pulley of the engine and the vehicle alternator have a large pulley ratio and are driven at a higher speed than the first vehicle alternator. . 7. The engine according to claim 3, wherein a load is directly connected to an output terminal of the second vehicle alternator, and an operation command is issued from an engine control unit only when power is required for the load. A charging system comprising a plurality of vehicle alternators, wherein the operation is stopped when the load does not require electric power. 8. The battery according to claim 1, wherein the first battery, the second battery, the first battery voltage and the second battery are connected to the first vehicle alternator and the second vehicle alternator. A charging system comprising a plurality of vehicle AC generators, wherein a voltage conversion circuit for converting the voltage of the battery is converted into a single case.