JP4544423B2 - Vehicle power supply - Google Patents

Description

  The present invention relates to a vehicle power supply device, and more particularly to a technique for supplying stable electric power to electrical components provided in a vehicle.

In recent years, vehicles equipped with large current actuators with relatively large loads such as electric power steering and electric air conditioners are increasing as electrical components.
Conventionally, vehicle power supplies have also supplied power to the large current actuator and other electrical components while charging the battery with the power generated by the alternator.
However, in such a configuration, when a large current actuator is operated, a large voltage drop occurs in the power supply for the vehicle, and the voltage is lower than the voltage required to operate the electrical component, and the operation of the electrical component becomes unstable. There was a problem.

Therefore, a switch is provided between the battery and the alternator, a large current actuator (for example, electric power steering (EPS)) is connected to the alternator side, and other electrical components are connected to the battery side. A technique for securing electric power necessary for a high-current actuator by disconnecting the alternator and the battery is known (see Patent Document 1).
JP 2003-137115 A

However, when the connection between the battery and the alternator is disconnected as in the technique disclosed in Patent Document 1, voltage fluctuation (ripple ripple) of the generated power by the alternator that has been alleviated by the battery when the battery and the alternator are in a connected state. Voltage) is not relaxed, and the voltage fluctuation of the generated power by the alternator increases.
When the voltage variation of the alternator increases in this way, power noise occurs, causing problems such as unstable operation of the high-current actuator, deterioration of radio reception, blinking of the headlight, and the like.

In addition, in order to sufficiently supply power to the high-current actuator only with the alternator, it is necessary to improve the power generation performance of the alternator, which may cause the alternator to be enlarged.
The present invention has been made to solve such a problem, and the object of the present invention is to stably operate a high-current actuator and other electrical components provided in a vehicle and to use an alternator. An object of the present invention is to provide a vehicular power supply device that can alleviate voltage fluctuations of generated power and suppress generation of power supply noise.

  In order to achieve the above object, in the vehicle power supply device according to claim 1, a battery connected to the first electric load, an alternator connected to the second electric load, and the battery and the alternator Current adjusting means provided between the battery and the alternator for adjusting a current flowing between the battery and the alternator; and a control means for controlling the current adjusting means in accordance with voltage fluctuation or current fluctuation of power generated by the alternator. It is characterized by having.

That is, a current adjusting means is provided between the battery and the alternator, a first electric load is connected to the battery, a second electric load is connected to the alternator, and the current adjusting means adjusts the current between the battery and the alternator. Is controlled according to the voltage fluctuation or current fluctuation of the power generated by the alternator.
According to a second aspect of the present invention, there is provided the vehicle power supply device according to the first aspect, wherein the current adjusting means is switching means capable of switching between connection and disconnection between the battery and the alternator, and the control means includes the alternator. And detecting the voltage fluctuation or current fluctuation of the generated power by the control circuit, and controlling the switching means by pulse width modulation so that the current flowing between the battery and the alternator increases or decreases in synchronization with the voltage fluctuation or the current fluctuation. It is characterized by.

That is, the current adjusting means is constituted by switching means capable of switching between connection and disconnection between the battery and the alternator, and the adjustment of the current between the battery and the alternator by the switching means adjusts the voltage fluctuation or current fluctuation of the generated power by the alternator. Control by pulse width modulation in synchronization with
According to a third aspect of the present invention, there is provided the vehicular power supply apparatus according to the second aspect, wherein the switching means is a ballast made of a semiconductor.

That is, pulse width modulation is realized using a semiconductor.
According to a fourth aspect of the present invention, there is provided the vehicle power supply device according to any one of the first to third aspects, wherein the control means once controls the current adjusting means to a current cutoff state when the first electric load starts to operate. The current adjusting means is controlled so that a current between the battery and the alternator is increased or decreased in synchronization with a voltage fluctuation or a current fluctuation of the alternator after starting.

That is, when the first electric load connected to the battery starts operating, the current flowing between the battery and the alternator is first interrupted by the current adjusting means (switching means), and the first electric load After the start of operation, the current adjusting means (switching means) is controlled in synchronization with the voltage fluctuation or current fluctuation of the generated power by the alternator.
According to a fifth aspect of the present invention, there is provided the vehicle power supply device according to the fourth aspect, wherein the first electric load is larger than the second electric load.

  That is, a first electric load having a relatively large load is connected to the battery, and a second electric load having a relatively small electric load is connected to the alternator.

  According to the vehicular power supply apparatus of the present invention using the above means, the current flowing between the battery and the alternator is controlled by the current adjusting means according to the voltage fluctuation or current fluctuation of the generated power by the alternator. The current flowing from the alternator to the battery can be adjusted in accordance with the voltage fluctuation or current fluctuation of the generated power due to. As a result, voltage fluctuation or current fluctuation of the generated power by the alternator can be mitigated, and generation of power supply noise can be prevented.

  According to the vehicle power supply device of claim 2, the connection and disconnection between the battery and the alternator are controlled by the pulse width modulation in synchronization with the voltage fluctuation or current fluctuation of the generated power by the alternator by the switching means. The current flowing from the alternator to the battery can be increased or decreased in accordance with the voltage fluctuation or current fluctuation of the power generated by the alternator while simply configuring the adjusting means using the switching means. As a result, voltage fluctuation or current fluctuation of the generated power by the alternator can be mitigated, and generation of power supply noise can be prevented.

  According to the vehicle power supply device of claim 3, by performing the pulse width modulation with a ballast constituted by a semiconductor, the switching means can be easily constituted by an analog circuit using a semiconductor, and the pulse width modulation can be performed at high speed. Therefore, the current flowing from the alternator to the battery can be appropriately increased or decreased in accordance with the voltage fluctuation or current fluctuation of the power generated by the alternator.

  According to the vehicle power supply device of the fourth aspect, the current flowing between the battery and the alternator is temporarily interrupted by the current adjusting means (switching means) at the start of the operation of the first electric load, so that the electric power generated by the alternator is reduced. A voltage drop can be prevented and stable electric power can be supplied to each electric load. After the operation of the first electric load is started, current adjusting means (switching) is synchronized with voltage fluctuation or current fluctuation of the generated power by the alternator. By controlling (means), it is possible to reduce the voltage fluctuation or current fluctuation of the generated power by the alternator generated on the alternator side by the interruption of the current, and to prevent the occurrence of power supply noise.

  According to the vehicle power supply device of the fifth aspect, when the first electric load having a relatively large load is connected to the battery and the second electric load having a relatively small electric load is connected to the alternator, Although there is a risk of a significant voltage drop in the power generated by the alternator due to the operation of the electrical load, the current drop between the battery and the alternator is temporarily interrupted by the current adjustment means (switching means) to prevent the voltage drop. Thus, stable electric power can be supplied to each electric load, and after the start of the operation of the first electric load, the current adjusting means (switching means) is controlled in synchronization with the voltage fluctuation or current fluctuation of the generated power by the alternator. As a result, voltage fluctuations or power generated by the alternator generated on the alternator side due to the interruption of the current To relax the change, it is possible to prevent the occurrence of power supply noise.

  Further, since a relatively small electric load is connected to the alternator side, a small alternator can be used.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Referring to FIG. 1, there is shown a schematic configuration diagram of a vehicle power supply device according to the present invention.
As shown in FIG. 1, a large current actuator 2 (first electric load) having a relatively large load such as an electric power steering and an electric air conditioner provided in the vehicle is connected to a battery 4.

In addition, another electrical component 6 (second electrical load) having a relatively small load other than the large current actuator 2 is connected to the alternator 8.
A ballast 10 (stabilizer, switching means, current adjusting means) is provided between the battery 4 and the alternator 8, and the battery 4 and the alternator 8 are connected via the ballast 10. The ballast 10 is a semiconductor relay such as a MOS-FET, for example, and switches between disconnection (ON) and connection (OFF) between the battery 4 and the alternator 8 (hereinafter referred to as “battery-alternator”). Note that the MOS-FET can perform appropriate ON-OFF switching at high speed (approximately every 1 nanosecond interval).

  Further, a resistor 12 is connected in parallel with the ballast 10 between the battery and the alternator, and the resistor 12 is connected to the battery-alternator even when the ballast 10 fails and cannot be switched on and off. Has a function of guaranteeing a failure so that it is not completely disconnected. Further, even when the ballast 10 is in the OFF state, it is possible to slightly reduce the increase in the voltage or current fluctuation of the alternator by passing a small current between the battery and the alternator via the resistor 12.

  The ballast 10 is connected to a ballast controller 20 (control means). The ballast control device 20 has a function of controlling ON / OFF switching of the ballast 10. Specifically, the ballast control device 20 uses a detection unit 22 that detects a ripple voltage (voltage fluctuation) of the generated power generated by the alternator 8, a reference voltage unit 24 that calculates a reference voltage, and a ripple voltage detected by the detection unit 22 as a reference. An adjustment unit 26 that offsets according to the voltage, a control unit 28 that calculates the ballast correction signal by synthesizing the offset voltage pattern with the ballast drive signal, and ON / OFF switching control of the ballast 10 It is comprised from the conversion part 30 converted into a signal. That is, the ballast control device 20 includes an analog circuit including the detection unit 22, the reference voltage unit 24, the adjustment unit 26, the control unit 28, and the conversion unit 30.

Further, the vehicle is provided with an ECU 40 (electronic control unit) that controls various devices. The ECU 40 is connected to the control unit 28 of the ballast control device 20 and has a function of transmitting a ballast drive signal when the large current actuator 2 is activated.
Hereinafter, the operation of the vehicle power supply device according to the present invention configured as described above will be described.
Referring to FIG. 2, the control routine executed by the ballast control device 20 when the large current actuator 2 is operated is shown in a flowchart. Also, referring to FIGS. 3 to 5, the alternator when the ballast is ON and when the ballast is OFF. The ripple voltage pattern when the ballast 10 is controlled according to the voltage ripple voltage pattern, the ballast correction signal pattern, and the ballast correction signal is shown. Hereinafter, description will be made based on the flowchart of FIG. 2 with reference to FIGS.

  In FIG. 2, in step S <b> 1, it is determined whether or not the control unit 28 has received a ballast drive signal from the ECU 40, that is, whether or not the large current actuator 2 is operating. If the determination result is false (No), the determination is repeated. On the other hand, if the determination result is true (Yes), that is, if the large current actuator 2 is activated and the control unit 28 receives a ballast drive signal from the ECU 40, the process proceeds to step S2.

In step S2, the ballast 10 is switched from the OFF (connected) state to the ON (disconnected) state in accordance with the ballast drive signal received in step S1.
In the next step S <b> 3, the detection unit 22 detects the generated voltage by the alternator 8. At this time, since the ballast 10 is in the ON state and the continuity between the battery 4 and the alternator 8 is cut off, the ripple voltage of the power generated by the alternator 8 is not relaxed by the battery current, as shown in FIG. The detected ripple voltage pattern (shown by a solid line) has an increased waveform compared to the ripple voltage pattern (shown by a broken line) when the ballast 10 is in the OFF state.

In step S4, the adjustment unit 26 offsets the ripple voltage pattern of the generated power by the alternator 8 detected by the detection unit 22 in accordance with the reference voltage received from the reference voltage unit 24, and the process proceeds to step S5.
In step S5, the control unit 28 calculates a ballast correction signal by combining the ripple voltage pattern offset in step 4 (hereinafter referred to as an offset voltage pattern) and the ballast drive signal received from the ECU 40. Specifically, as shown in FIG. 4, the ballast correction signal is calculated by synthesizing the offset voltage pattern on the ON portion of the ballast drive signal. The ballast correction signal calculated in this way is such that the voltage fluctuates slightly from the ON state to the OFF side. If the duty ratio is 100% when the ballast drive signal is in the ON state, the ballast correction signal is It can be said that this is a ballast drive signal having an average duty ratio of approximately 90%.

In the next step S <b> 6, the conversion unit 30 converts the ballast correction signal calculated in step S <b> 5 into an ON / OFF switching control signal executed by the ballast 10. Specifically, the waveform of the ballast correction signal is converted into a so-called PWM (pulse width modulation) control signal that is controlled by the ratio of the time in the ON state and the time in the OFF state.
In step S7, the ballast correction signal converted in step S6 is output to the ballast 10, thereby switching the ballast 10 on and off according to the ballast correction signal.

  As described above, the ballast 10 is controlled according to the ballast correction signal calculated from step S3 to step S6, so that the current flowing through the ballast 10 varies according to the ballast correction signal in synchronization with the ripple voltage pattern. become. Thus, the conduction between the battery and the alternator is in a half-cut state with an average duty ratio of about 90%, and the ripple voltage pattern of the generated power by the alternator 8 is the amount of current flowing from the alternator 8 to the battery 4 as shown in FIG. Only a reduced waveform is obtained.

  In the next step S8, it is determined again whether the ballast drive signal is received. That is, it is determined whether or not the large current actuator 2 continues to operate. If the determination result is true (Yes), the process returns to step S3. That is, the ballast correction signal is calculated again, and control according to the ripple voltage of the alternator 8 is always performed while the large current actuator 2 is operating. On the other hand, if the determination result is false (No), that is, if the large current actuator 2 is stopped, the routine is exited.

  As described above, in the vehicular power supply device according to the present invention, when the large current actuator 2 starts operating while the ballast control device 20 is simply configured with an analog circuit with high responsiveness, By cutting off the current flowing between the battery and the alternator, it is possible to prevent a voltage drop of the generated power by the alternator 8 and to stably supply power to the large current actuator 2 and other electrical components 6. And also about the increase in the ripple voltage of the generated power by the alternator 8 caused by the interruption, the ballast drive signal is corrected so as to be synchronized with the ripple voltage pattern, and the ballast 10 is controlled according to the ballast correction signal. In addition, the current flowing from the alternator to the battery can be increased or decreased, and the ripple voltage can be reduced. Thereby, generation | occurrence | production of power supply noise can be prevented and the deterioration of reception of a radio etc., the blink of a headlight, etc. can be prevented reliably.

The large current actuator 2 is connected to the battery 4, and the alternator 8 is connected to another electrical component 6 having a relatively small electrical load, so that a small alternator can be used.
Although the description of the embodiment of the vehicle power supply device according to the present invention has been completed above, the embodiment is not limited to the above embodiment.

For example, in the above embodiment, since the ballast 10 is composed of a MOS-FET, the ballast control device 20 performs control based on the voltage of the power generated by the alternator. However, the ballast 10 is composed of, for example, a transistor, You may control based on.
Further, the ballast 10 may be configured by using, for example, other semiconductor relays other than the MOS-FET and the transistor as long as the connection between the battery and the alternator can be switched between connection and disconnection. It may be configured by a simple switch device or the like.

Although the ballast 10 is used here, the ballast 10 is not limited to such an ON-OFF control. For example, a variable resistor may be used as long as the current flowing between the battery and the alternator can be controlled.
Moreover, in the said embodiment, although the ballast control apparatus 20 is comprised from the detection part 22, the reference voltage part 24, the adjustment part 26, the control part 28, and the conversion part 30, it is not restricted to such a structure.

1 is a schematic configuration diagram of a vehicle power supply device according to the present invention. It is a flowchart which shows the control routine performed by the ballast control apparatus in the power supply device for vehicles concerning the present invention at the time of operation of a large current actuator. It is the figure which showed the ripple voltage pattern of the alternator voltage at the time of ballast ON and ballast OFF. It is the figure which showed the ballast correction signal. It is the figure which showed the ripple voltage pattern at the time of controlling a ballast according to a ballast correction signal.

Explanation of symbols

2 Large current actuator (first electrical load)
4 Battery 6 Alternator 8 Other electrical components (second electrical load)
10 Ballast (ballast, switching means, current adjustment means)
20 Ballast control device (control means)
40 ECU

Claims (5)

A battery connected to the first electrical load;
An alternator connected to a second electrical load;
A current adjusting means provided between the battery and the alternator, capable of adjusting a current flowing between the battery and the alternator;
Control means for controlling the current adjusting means in accordance with voltage fluctuation or current fluctuation of power generated by the alternator;
A vehicle power supply apparatus comprising: The current adjusting means is a switching means capable of switching between connection and disconnection between the battery and the alternator,
The control means detects the voltage fluctuation or current fluctuation of the generated power by the alternator, and the switching means adjusts the current flowing between the battery and the alternator to increase or decrease in synchronization with the voltage fluctuation or the current fluctuation. The vehicle power supply device according to claim 1, wherein the vehicle power supply device is controlled by pulse width modulation.   The vehicular power supply device according to claim 2, wherein the switching means is a ballast made of a semiconductor.   The control means controls the current adjusting means once in a current interruption state at the start of operation of the first electric load, and the current between the battery and the alternator after the start of the operation is a voltage fluctuation or current of the alternator. 4. The vehicle power supply device according to claim 1, wherein the current adjusting means is controlled to increase or decrease in synchronization with fluctuation.   5. The vehicle power supply device according to claim 4, wherein the first electric load is larger than the second electric load. 6.

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