JP3622633B2 - Charging system with multiple AC generators for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a charging system provided with a vehicular AC generator, and more particularly to a vehicular AC generator charging system suitable as an automobile power generator.
[0002]
[Prior art]
Conventional vehicular AC generators include the following known examples. First, as described in Japanese Patent Application Laid-Open Nos. 61-125964 and 61-1555056, the first and second known examples use the first vehicular AC generator for 12V system power generation. A second vehicle alternator using a power source for electric power steering is disclosed. As a power source for the electric power steering, power is supplied only from the second vehicle alternator, and no battery for the second vehicle alternator is provided. As the third and fourth known examples, there are two low-voltage side vehicle alternators and high-voltage side vehicle alternators described in JP-A-2-97236 and JP-A-3-183331. A vehicle equipped with a stand is disclosed, and when power on the low voltage side is insufficient, power is supplied to the low voltage side from the AC generator for the high voltage side. As a fifth known example, Japanese Patent Application Laid-Open No. 5-212727 discloses a vehicle AC generator for low pressure or high pressure, in which a high pressure side load and a low pressure side load are connected. A configuration is disclosed in which both batteries can be charged. As a sixth known example, the output of one vehicular AC generator configured to rotate at a constant speed as described in JP-A-6-62539 is a DC voltage output and an AC voltage 2 There are various types of output, the AC voltage side output is configured to charge the low voltage side battery via the voltage conversion circuit, and the DC voltage output is directly connected to the high voltage side.
[0003]
[Problems to be solved by the invention]
In the above 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, but there is no means for supplying power to each other. Therefore, an AC generator for a vehicle corresponding to each load is required, leading to an increase in the size of the individual AC generator for a vehicle. Further, in the third and fourth known examples, power supply from the high voltage side to the low voltage side is possible, but it is a configuration that cannot cope with a shortage of power on the high voltage side. In the fifth known example, one vehicle alternator is configured to be charged with two types of voltages. Since the number of vehicle alternators is one, the physique may be increased. In addition, when one vehicle alternator fails, there is a problem that both power supplies stop charging. In the sixth known example, in order to create two power sources of a low-voltage side power source and a high-voltage side power source in the same manner as the fifth known example from a vehicle AC generator configured to be able to rotate at a constant speed, If the alternator fails, the power supply of either system cannot be charged and the vehicle cannot run.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to propose a system capable of mutually supplying electric power in a vehicle system that requires a low-voltage power supply and a high-voltage power supply so that the other power supply can be charged from either power supply. Is.
[0005]
[Means for Solving the Problems]
The present invention is a vehicle charging system including at least two power supplies, and includes at least two vehicle alternators provided corresponding to the at least two power supplies and a voltage provided between the at least two power supplies. The vehicle AC generator includes a rotor that generates a rotating magnetic field, and a stator that is arranged at a predetermined interval from the rotor and generates an AC voltage by magnetization of the rotor. A stator having windings, and a rectifier circuit that converts an AC voltage into a DC voltage. A battery is connected in parallel to one side of the vehicle AC generator, and the other side of the vehicle AC generator A load circuit is directly connected to the output terminal on the side, and the field current supplied to the other side of the vehicle alternator is supplied from a battery connected in parallel to one side of the vehicle alternator. Voltage change The circuit converts between the output voltage on one side of the vehicle alternator and supplies it to a load circuit directly connected to the output terminal on the other side of the vehicle alternator. It is provided.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
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 the low-voltage side 12V battery 3, and the 12V electric load 5 is also connected in parallel. At this time, the negative side of the battery 3 for 12 V is the ground potential of the electronic circuit system and is connected to the vehicle body of the vehicle. Next, the second vehicular AC generator 2 is connected in parallel with the 36 V battery 4 and the 36 V load circuit 6. The output of the first vehicle alternator is connected to the output of the second vehicle alternator 2 via the DC voltage conversion circuit 7. The output of the second vehicular AC generator 2 is connected to the output of the first vehicular AC generator 1 via a DC voltage conversion circuit 8. The arrows in the figure indicate the direction of power movement.
[0007]
Each of the DC voltage conversion circuits 7 and 8 converts an input side voltage into an output side voltage. In the present embodiment, the DC voltage conversion circuit 7 corresponds to a booster circuit, and the 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 the other load having a different voltage. In addition, since either one of the DC voltage conversion circuit 7 or the DC voltage circuit 8 is controlled to operate, even if it has a function capable of converting the step-up / step-down with one circuit configuration, it can be used. good.
[0008]
Next, the reason why a configuration in which two vehicle alternators are provided will be described. As in the conventional example, in the known example, since one power source is generated using one vehicle AC generator and the second voltage must be generated using a voltage conversion circuit, Two types of power sources must be created with the vehicle alternator. Therefore, since the power generation capacity of the vehicle alternator has to be increased, there is a drawback that the size of the vehicle alternator increases. Moreover, if the physique is large, it will lack in-vehicle property. In the present embodiment, the high-voltage side 36V power supply is assumed to be a power supply used for a relatively large electric power, and is used for an electrocatalyst, an auxiliary power motor, and the like. For example, taking an electrocatalyst as an example, the time when the electric power is most necessary is immediately after the engine is started and when the engine speed is almost the idling speed. Since the conventional vehicle alternator has a pulley ratio of about 2.5 times the engine speed, it is multiplied by 2.5 times assuming that the idling speed is 800 r / min. Then, it was necessary to supply the maximum power at 2000 r / min. As a result, he did not gain an increase in physique.
[0009]
In the present invention, a plurality of vehicle AC generators are operated independently according to the required power supply, and in-vehicle performance is taken into consideration, and the output of each vehicle generator is converted to a DC voltage so that it can be used by another power supply. It is configured via a circuit. Therefore, it goes without saying that the individual vehicle alternator can be made smaller, and the pulley ratio with the engine can be set separately according to the load used, so that the rotational speed can be changed according to the load. In addition, by providing a vehicular AC generator for each generated voltage, even if a problem occurs in one vehicular AC generator, backup can be performed with the remaining vehicular AC generator and a step-up / down circuit. The worst situation can be avoided.
[0010]
The low-voltage side 12V power source described above is a power source supplied to a load such as a lamp or an electronic circuit. The high-voltage side 36V power source is a motor drive power source, electrocatalyst, molten glass or the like having a relatively large power. It does not require power, and large power is consumed in a short time. Therefore, power is always stored in the high-voltage side 36V battery 4, and the power is supplied by operating the battery 4 and the second vehicular AC generator 2 when power is required. Further, when the electric power from the low-voltage side 12V load is insufficient and cannot be generated by the vehicle alternator 1, the DC voltage conversion circuit 8 is operated to supply electric power from the high-voltage side to the low-voltage side. . As for 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. A specific operation will be described in the case where current is supplied from the high voltage side to the low voltage side vehicle alternator 1 side. The generated voltage of the vehicle alternator 1 is about 14.5 V when there is no load, but the terminal voltage of the battery 3 decreases as the current flowing through the electric load 5 increases. 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 power generation of the first vehicular AC generator 1 occurs. The power can be supplied from the high voltage side, and the discharge of the low voltage battery can be prevented. On the other hand, if the DC voltage conversion circuit 7 is set to operate when the battery terminal voltage on the high-voltage side becomes 40.5 V or less, the power generation by the second vehicular AC generator 2 is insufficient. Can supply power from the low voltage side to the high voltage side. In addition, when the low voltage and high voltage drop at the same time, the stability of the control system is achieved by giving priority to the low-voltage power supply that supplies the power of the engine control unit that controls the engine. .
[0011]
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 first low-voltage vehicle alternator 1. The negative side of the battery 3 is grounded to the vehicle body and serves as a reference potential for the power source. The high-voltage power supply circuit has a high-voltage load circuit 6 connected to the output terminal of the second vehicular AC generator 2, and the reference potential is the same as the low-voltage reference potential described above. The DC voltage conversion circuit 7 has a configuration in which the booster circuit 7 is arranged so that charging can be performed by converting the voltage from the low voltage side to the high voltage side. As shown by the arrows in the figure, the power flow is in one direction from the low pressure side to the high pressure side. This is because the power supply time is short due to the characteristics of the load used on the high voltage side. Even if the low-voltage side battery 3 is somewhat burdened, the high-voltage side vehicle alternator 2 can be downsized. In this case, the field current of the vehicle AC generator 2 on the high voltage side is supplied with power 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 high-voltage side vehicle alternator 2 is operated by the signal 10 from the engine control unit 9 (ECU). The engine control unit 9 detects the load demand on the high pressure side and turns on / off the high voltage side vehicle alternator 2. The engine control unit 9 constantly monitors the terminal voltage of the 12V battery 3 (not shown) so that the low-voltage side battery 3 is not overdischarged.
[0012]
As shown in FIG. 2, there is no power demand on the high-voltage side by operating the second vehicular AC generator 2 only when power is supplied to the high-voltage load 6 that operates discontinuously. In this case, control is performed so that power generation is stopped by a signal 10 from the engine control unit 9 so that the second vehicular AC generator 2 does not generate power. The DC voltage conversion circuit 7 detects the voltage on the output side, and in the case of the present embodiment, the high voltage side power supply is assumed to be 36V, so when the voltage becomes 40.5 V or less, the DC voltage conversion circuit 7 7 is turned on to supply power from the low voltage side to the high voltage side.
[0013]
FIG. 3 illustrates the configuration of a vehicle AC generator that is actually attached to the engine in the first embodiment.
[0014]
FIG. 3 shows a state where the two vehicle alternators described in FIG. 1 are connected via the crank pulley of the engine. The configuration will be described. The pulley 12 of the first vehicle alternator 1 is connected to the crank pulley 13 of the engine 11 via a belt. Since the first vehicle alternator 1 always rotates for use at a low voltage, the pulley ratio is set to about 2.5 times. The pulley 14 of the second vehicular AC generator 2 is connected to the crank pulley 15 of the engine 11 via a belt. The operation of the second vehicular AC generator 2 is assumed to be an operation only when the engine is started, so the pulley ratio is about 4 times larger than the pulley ratio of the first vehicular AC generator 1. Even if the engine 11 is idling and rotating, the rotation speed is set so that sufficient output can be obtained. As described above, the low voltage side 12V battery 3 and the low voltage side load circuit 5 are connected to the load side of the first vehicle alternator 1. A high voltage side 36V battery 4 and a high voltage side load circuit 6 are connected to the load side of the second vehicular AC generator 2. A DC voltage conversion circuit 78 is disposed 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 and high-voltage battery voltages are lower than the reference voltage, the low-voltage charging is prioritized.
[0015]
FIG. 4 shows a circuit configuration of the DC voltage conversion circuit 78 described in FIG. The configuration will be described. A smoothing capacitor 22 is connected in parallel between both terminals of the low-voltage 12V battery 3. The positive terminal of the capacitor 22 is connected to the reactor 21 and the other is connected to the collector of the boosting transistor 23. The collector is connected to the cathode of the step-up diode 24, the emitter of the step-down transistor, and the anode of the step-down diode 26. The collector of the step-down transistor 25, the cathode of the step-down diode 26, the positive side of the smoothing capacitor 27, and the positive 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 boosting diode 24, the emitter of the boosting transistor 23, the negative side of the capacitor 22, and the negative terminal of the low voltage side battery 3. An output of the AND circuit 28 is connected to the base of the boosting transistor 23, and a boost / step-down selection signal U / D for selecting boost or step-down and a duty signal Ud at the time of boost are connected to two inputs of the AND circuit 28. Has been. The step-up / step-down selection signal U / D described above is also connected to the input side of the inverter circuit 30, and the output of the inverter circuit 30 is connected to the input of the AND circuit 29. A step-down duty signal Dd is connected to the other input of the AND circuit 29, and an output signal of the AND circuit 29 is connected to the base of the step-down transistor 25.
[0016]
The operation of the above configuration will be described. First, the case where the voltage is increased from the low voltage side battery 3 to the high voltage side battery 4 will be described. In this case, it operates 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 is lower than the above-mentioned value of 40.5 V, the boost / step-down selection signal U / D is set to the H level in order to operate the boost circuit. Then, the duty of the boost duty signal Ud applied to the base of the boosting transistor 23 is determined so that the terminal voltage of the step-down battery 4 is about 40.5V. 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 electric power used by the load 5 on the low voltage side becomes larger than the amount of power generated by the AC generator 1 for the low voltage side, and the terminal voltage of the battery 3 on the low voltage side is 13.5V. It works 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 is lower than the reference voltage (13.5 V), the boosting / lowering selection signal U / D is set to L level output. Therefore, the output of the AND circuit 28 becomes L level,
The output signal of the AND circuit 29 becomes H level. The engine control unit determines the previous duty of the step-down duty signal Dd so that the terminal voltage of the low voltage side battery 3 is about 13.5V. In the above description, a transistor is used for the step-up / step-down switch. However, if a switching element such as a MOS-FET or IGBT is used, the same function is achieved. In addition, the voltage detection level at which the booster circuit and the step-down circuit operate is described as 13.5V in the case of a low voltage and 40.5V which is three times 13.5V on the high voltage side, but this voltage may be slightly changed. . In addition, although the conversion voltage for voltage conversion has been described as 10.5 V for the low voltage and 40.5 V, which is three times 13.5 V for the high voltage side, this voltage value may be slightly increased. However, when it is increased, it is necessary to provide hysteresis to the operating voltage.
[0017]
FIG. 5 shows a case where 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. 1 shows a booster circuit configuration for supplying power from a low voltage side to a high voltage side. First, the configuration will be described. One terminal of the reactor 21 is connected in series to the plus 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 positive side of the smoothing capacitor 27 and the positive side of the high-voltage battery 4 are connected to the cathode side of the diode 26. Side terminals are 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 mentioned above, the boosting operation has a calculation unit such as an engine control unit or a comparator that can output a duty only when the detected voltage is lower than the reference voltage preset in the analog circuit. The boosting duty of the transistor is determined by the comparison circuit used.
[0018]
The feature of the step-up / down circuit is to reduce the size of the high-voltage side vehicle alternator 2 in a system based on the assumption that the high-frequency side load is used less frequently. When the load current on the low high voltage side is insufficient, power is supplied from the low voltage side.
[0019]
In the above description, the case where two vehicle alternators are driven by one engine has been described. However, in the case of a vehicle equipped with two engines, the low voltage side vehicle alternator and the high pressure side The vehicle alternator can also be driven by a separate engine. For example, examples of mounting two engines include a bus and a camper.
[0020]
Next, a structure in which the low voltage side and high voltage side batteries and the DC voltage conversion circuit are integrated and miniaturized will be described with reference to FIG. First, the configuration will be described. A low voltage side battery 3 and a high voltage side battery 4 are arranged inside the case 40. A DC voltage conversion circuit 78 is arranged between the batteries in order to convert the voltages of both batteries. Each battery is connected by a wiring 41, and terminals of both batteries are connected to the low-voltage vehicle alternator 1 and the high-voltage vehicle alternator 2. As shown in this figure, a compact arrangement can be realized by integrating the battery and the DC voltage conversion circuit. As shown in the figure, the case 40 may be made of a plastic material made of a heat insulating material, but may be shielded with a metal case so as not to emit switching noise to the outside.
[0021]
In the present invention, the ground level on the low-voltage side and the high-voltage side are described as the same. However, for example, when the voltage on the high-voltage side is equal to or higher than the 36V power supply, it may be better to insulate the high-voltage side. . In that case, it is realizable with the structure which has arrange | positioned the insulation transformer in the part of a booster circuit.
[0022]
As described above, the object of the present invention is to realize power sharing between the low voltage side and the high voltage side, and has the effect of reducing the size of each vehicle AC generator and the size of the battery.
[0023]
【The invention's effect】
As described above, according to the present invention, even when one of the low-voltage side and high-voltage side AC generators breaks down, the low-voltage side and high-voltage side power is supplied by the one-side vehicle AC generator. As a result, it is possible to safely drive the car to the repair shop using the minimum functions.
[Brief description of the drawings]
FIG. 1 is a configuration diagram for charging the voltage of two power sources using two vehicular AC generators for explaining the first embodiment.
FIG. 2 is a system configuration diagram illustrating a second embodiment.
FIG. 3 is a layout diagram of an engine and an AC generator for a vehicle.
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 ... Low voltage side vehicle AC generator, 2 ... High voltage side vehicle AC generator, 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 (Boost 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 ... power supply for excitation, 21 ... Reactor, 22, 27 ... Capacitor, 23, 25 ... Transistor, 24, 26 ... Diode, 28, 29 ... AND circuit, 30 ... Inverter circuit, Ud ... Boost duty signal, Dd ... Buck duty signal, U / D ... Step-up / step-down selection signal, 40 ... case, 41 ... wiring,
78 ... Buck-boost DC voltage conversion circuit.

Claims (6)

A vehicle charging system with at least two power sources,
At least two vehicular AC generators corresponding to at least two power sources;
A voltage conversion circuit provided between at least two power sources,
The vehicle alternator is
A rotor that generates a rotating magnetic field;
A stator having a stator winding disposed at a predetermined interval from the rotor and generating an alternating voltage by magnetization of the rotor;
A rectifier circuit for converting the AC voltage into a DC voltage,
A battery is connected in parallel to one side of the vehicle alternator,
A load circuit is directly connected to the output terminal on the other side of the vehicle alternator,
The field current supplied to the other side of the vehicle alternator is supplied from a battery connected in parallel to one side of the vehicle alternator,
The voltage conversion circuit converts at least the output voltage on one side of the vehicle alternator and supplies it to a load circuit directly connected to the output terminal on the other side of the vehicle alternator. A charging system comprising a plurality of vehicle AC generators, which is provided between two power sources. Oite charging system comprising an AC generator for a plurality of vehicles according to claim 1,
One side of the AC generator for the vehicle is intended to be operated continuously,
The other side of the vehicle AC generator, the charging system comprising an AC generator for a plurality of vehicles, characterized in that to operate discontinuously, depending on the load. In the charging system comprising a plurality of vehicle alternators according to claim 1,
A charging system comprising a plurality of vehicle AC generators, wherein the other side of the vehicle AC generator is activated and stopped by a signal from an engine control unit. In the charging system comprising a plurality of vehicle alternators according to claim 1,
The vehicle alternator is connected by a belt so as to rotate in conjunction with a crank pulley of the engine,
A charging system comprising a plurality of vehicle AC generators, wherein the output voltages of the vehicle AC generators are different. In the charging system comprising a plurality of vehicle alternators according to claim 1,
The other side of the vehicle alternator is
The output voltage is higher than one side of the vehicle alternator,
The ratio of the pulley to the crank pulley of the engine is larger than the ratio of the pulley on one side of the vehicle alternator to the crank pulley of the engine, and is driven at a higher speed than the one side of the vehicle alternator. A charging system comprising a plurality of vehicle AC generators. In the charging system comprising a plurality of vehicle alternators according to claim 1,
The other side of the vehicle alternator operates when instructed by an operation command from the engine control unit only when power needs to be supplied to a load circuit directly connected thereto, and when power supply is required. Is a charging system comprising a plurality of vehicle AC generators, characterized in that operation is stopped.

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