JP4502595B2 - Automotive power circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automobile power supply circuit.
[0002]
[Prior art]
Conventionally, for example, an AC generator is connected to an engine, and a battery is charged by an AC voltage of an AC generator that rotates in conjunction with the rotation of the engine (see, for example, Patent Document 1).
[0003]
For example, FIG. 6 shows an example in which a power circuit of a small motorcycle is configured as described above. In the figure, a power input terminal 2a of a battery voltage control circuit 2 is connected to a voltage terminal 1a of an AC generator (ACG), and a DC load 3 and a battery 4 are connected to a charging terminal 2b of the battery voltage control circuit 2. Yes.
[0004]
In the voltage control circuit 2, the thyristor SCR1 is connected in a direction in which a current flows from the power input terminal 2a to the charging terminal 2b. The thyristor SCR1 is controlled by a battery voltage detection circuit 5 connected to its gate. The battery voltage detection circuit 5 detects the voltage (battery voltage) at the charging terminal 2b, and turns on the thyristor SCR1 when the battery voltage is lower than a predetermined lower limit value.
[0005]
The cathode of the lamp lighting thyristor SCR2 is connected to the power input terminal 2a, and the anode of the thyristor SCR2 is connected to the lamp connection terminal 2c. The lamp connection terminal 2c is connected to a lamp 6, for example a headlamp, having one end grounded. The thyristor SCR2 is controlled by a lamp voltage detection circuit 7 connected to its gate. The lamp voltage detection circuit 7 detects the voltage (negative voltage) at the lamp connection terminal 2c, and turns off the thyristor SCR2 when the lamp 6 reaches a predetermined voltage or higher to control the lighting of the lamp 6. .
[0006]
In addition, a capacitor C1 is connected to a node between the thyristor SCR1 and the charging terminal 2b via a diode D1 that is directed to pass a current toward the ground side. An output terminal 2d for supplying a voltage to the external engine control load 8 is taken out from the node of the diode D1 and the capacitor C1. The engine control load 8 is composed of various electric components corresponding to the digitization of engine control systems in recent years.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-149562 (right column on page 3, FIG. 1)
[0008]
[Problems to be solved by the invention]
However, in small motorcycles, a small-capacity battery is used, and the battery may be in a so-called battery disconnection state such as battery voltage drop or battery line disconnection due to insufficient maintenance. A kick pedal that enables the engine to rotate from the outside is provided so that the engine can be started even in such a case.
[0009]
On the other hand, in recent small motorcycles, the engine control load 8 and the like electronically controlled as described above are used from the viewpoint of improving fuel efficiency, and the load on the battery tends to increase more and more. Under such circumstances, there is a problem that engine start-up becomes more difficult if the battery falls off. And when the battery voltage is insufficient, the starter cannot start as expected and kick starts. In this case, the rotation speed of the alternator is low, so only a low voltage may be generated. A sufficient voltage cannot be supplied to the engine control load 8. As a countermeasure, the above-described capacitor C1 is used as a pseudo-stabilized power source.
[0010]
The potential of the terminal 2b in the case where the battery voltage is insufficient is shown by a solid line in FIG. The capacitor C1 is charged by the positive voltage waveform, but is discharged to drive the engine control load 8 in the waveform disappearance section (between the positive half-wave waveform), so the potential is shown by an imaginary line in the figure. It becomes like this. Therefore, since it is necessary to increase the capacity of the capacitor C1 in order to ensure stable driving of the engine control load 8, there is a problem that the apparatus is increased in size and cost.
[0011]
[Means for Solving the Problems]
In order to solve such a problem and to reduce the capacity of a capacitor serving as a pseudo power source at the time of start-up due to insufficient battery voltage, etc., in the present invention, an AC generator driven by an engine and A battery, an engine control load connected to the battery, a positive voltage drive circuit for charging the battery and driving the engine control load with a positive voltage waveform of the AC generator, and a negative voltage of the AC generator A power supply circuit for an automobile having a negative voltage drive circuit for driving a negative voltage drive load by a waveform, wherein the AC generator has a phase of 180 with respect to a first coil and an output waveform of the first coil. and a second coil which is adapted to output a time shifted waveform, the positive voltage driver circuit, wherein the engine each positive voltage waveform is continuously output from each coil Having respective positive voltage rectifier circuit connected respectively to the each coil so as to be output to the control load, the negative voltage drive circuit, wherein the negative voltage each negative voltage waveform is continuously output from each coil Each negative voltage rectifier circuit connected to each coil so as to be output to the drive load, and each positive voltage in the full-wave rectification state between the positive voltage drive circuit and the engine control load It is assumed that a pseudo power supply capacitor is provided for charging with the waveform and driving the engine control load with the charge / discharge waveform .
[0012]
According to this, since the waveform from the AC generator is 180 degrees out of phase with each other, the first and second coils are output and only each positive voltage waveform is passed through the positive voltage drive load. A positive voltage waveform is obtained. For example, in a small motorcycle that starts with a kick when the battery voltage is insufficient, if the start control circuit is used as a positive voltage drive load, a sufficient output is required for the positive voltage drive load. With this configuration, an output with a positive voltage waveform in the full-wave rectification state is obtained, and the space between the waveforms is reduced to about half of that using the positive voltage waveform of the half-wave rectification, so a pseudo power supply capacitor is provided as a battery replacement In this case, the discharge time is shortened, a high charging voltage of the capacitor is ensured, and sufficient power can be supplied to the positive voltage drive load even when generating power at a low rotational speed at the time of kicking start.
[0013]
In particular, the coils are connected in series with each other and their commons are grounded, and the positive voltage rectifier circuit has unidirectional energization elements respectively connected to output terminals of the coils, and the negative voltage rectifier circuit. However, it is preferable to have each one-way energization element connected to the output terminal of each coil.
[0014]
According to this, since the full-wave rectified waveforms of the positive voltage waveform and the negative voltage waveform can be obtained with a small number of elements (a total of four for each of two for positive voltage / negative voltage rectification), the circuit configuration is A power supply circuit that can be simplified and reduced in cost can be provided.
[0015]
The waveforms output from the coils may be shifted in phase by 180 degrees by changing the winding direction of the coils or the magnetization direction of the permanent magnet facing the coils. .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on specific examples shown in the accompanying drawings.
[0017]
FIG. 1 is a diagram showing a power circuit of a small motorcycle to which the present invention is applied. It should be noted that the same parts as those in FIG. 6 shown in the conventional example are denoted by the same reference numerals, and detailed description thereof is omitted. Even in the battery voltage control circuit 2, a power input terminal 2a, a charging terminal 2b, a lamp connection terminal 2c, and an output terminal 2d are provided.
[0018]
The AC generator 1 is provided with a first coil L1 and a second coil L2, both coils L1 and L2 are connected in series with each other, and a node thereof is grounded. The first voltage terminal 1a is provided on the side opposite to the ground side of the first coil L1, and the first voltage terminal 1a is connected to the power input terminal 2a. The second voltage terminal 1b is provided on the side opposite to the ground side of the second coil L2, and the second voltage terminal 1b is connected to the second power input terminal 2e provided in the battery voltage control circuit 2. Yes.
[0019]
As in the conventional example, a DC load 3 as a positive voltage drive load and a battery 4 are connected to the charging terminal 2b, and an engine control load as a positive voltage drive load in parallel with the DC load 3 is connected to the output terminal 2d. 8 and a control circuit (ECU) 9 are connected to the lamp connection terminal 2c, for example, a lamp 6 as a headlamp as a negative voltage drive load. Examples of the engine control load 8 include a spark plug, an ignition coil, and an electronic ignition control circuit. The thyristor SCR1 and the battery voltage detection circuit 5 constitute a positive voltage drive circuit.
[0020]
In the battery voltage control circuit 2, a thyristor SCR3 is provided between the lamp connection terminal 2c and the node of the thyristor SCR2 and the second power input terminal 2e. In the thyristor SCR3, the anode is connected to the lamp connection terminal 2c and the node of the thyristor SCR2, and the cathode is connected to the second power input terminal 2e. These thyristors SCR2 and SCR3 are provided as negative voltage conducting elements. Also, each diode D2 as a positive voltage energizing element that allows current to flow toward the thyristor SCR1 between the power input terminal 2a and the thyristor SCR1 and between the second power input terminal 2e and the thyristor SCR1. -D3 is provided.
[0021]
The gate of the thyristor SCR1 is controlled by the battery voltage detection circuit 5 as in the conventional example, and the gate of the thyristor SCR3 is controlled by the ramp voltage detection circuit 7 similarly to the gate of the thyristor SCR2. These thyristors SCR2 and SCR3 and the ramp voltage detection circuit 7 constitute a negative voltage drive circuit.
[0022]
An example of the AC generator 1 applicable to the present invention is shown in FIG. For example, the coils L1 and L2 are alternately wound around each pole of an 8-pole stator, and the winding directions thereof are indicated by solid arrows and broken arrows in the figure with respect to the normal winding direction indicated by an imaginary line in the figure. Make the orientation shown in. In the case of a normal winding, adjacent ones are paired, whereas in the illustrated example, a pair of adjacent coils L1 with a coil L2 in between is paired, A pair of adjacent coils L2 across the coil L1 form a pair.
[0023]
By winding in this way, when the voltage output of the coil L1 becomes as shown in the upper stage shown by the terminal 1a in FIG. 3, the voltage output of the coil L2 becomes like the lower stage shown in the terminal 1b of FIG. The AC waveforms are 180 degrees out of phase. Note that the structure for outputting voltage waveforms whose phases are shifted from each other by 180 degrees from the coils L1 and L2 is not limited to the difference in the winding method of the windings. For example, in the magnetization direction of the permanent magnet on the rotor side It is also possible to change the combination.
[0024]
The control circuit 9 can detect the battery voltage by detecting the voltage at the power supply terminal 2d, and is connected to the lamp voltage detection circuit 7 so as to control the thyristors SCR2 and SCR3, thereby controlling the engine control system. The engine control load 8 is connected as much as possible. The control circuit 9 also receives a rotational speed detection signal from a pickup coil 10 provided in the AC generator 1 for detecting the engine rotational speed as a start detection means.
[0025]
Next, the control procedure by the battery voltage control circuit 2 according to the present invention will be described below. The target small motorcycle can be started by kicking a kick pedal that can be engaged with a crankshaft of an engine. In the description of the illustrated example, it can be started by a starter motor, but may be always kick-started.
[0026]
When the charge amount of the battery 4 is sufficient, the engine can be started by the starter motor by turning on a starter switch (not shown). In this case, the voltage necessary for driving the engine control load 8 can be supplied from the battery 4.
[0027]
On the other hand, since the starter motor cannot start the battery 4 in an insufficient voltage state when the charge amount of the battery 4 decreases or the battery comes off, the kick pedal is kicked and started as described above. To do.
[0028]
When the AC generator 1 rotates, AC waveforms having phases shifted from each other by 180 degrees are output from the coils L1 and L2 as shown in FIG. As shown by the solid line and the broken line in FIG. 1, currents in opposite directions flow alternately in both coils L1 and L2. Therefore, the positive voltage waveform of the first coil L1 passes through the diode D2, the positive voltage waveform of the second coil L2 passes through the diode D3, and the charging terminal 2b has a continuous positive voltage waveform as shown in FIG. Is output. The DC load 3 is driven by this continuous positive voltage waveform, and the potential of the capacitor C1 is charged and discharged as shown by the imaginary line in the figure, and the engine control load 8 can be driven by the charge / discharge waveform.
[0029]
As described above, since the positive voltage waveform in the full-wave rectification state is output to the charging terminal 2b, the capacitor is approximately half the cycle with respect to the potential change (the broken-line waveform in FIG. 4) by the conventional half-wave rectification. C1 is charged. Therefore, in the conventional case, it was necessary to increase the capacity of the capacitor in order to suppress a voltage drop due to a long discharge time, whereas the capacity of the capacitor C1 can be reduced, thereby reducing the cost of the circuit. .
[0030]
Further, the negative voltage waveform of the first coil L1 turns around the ground side and passes through the thyristor SCR2 via the lamp 6, and the negative voltage waveform of the second coil L2 turns around the ground side and turns around the thyristor via the lamp 6 similarly. In order to pass through the SCR 3, a continuous negative voltage waveform is output to the lamp connection terminal 2c as shown in FIG. Since the lamp 6 can be driven by this continuous negative voltage waveform, when viewed from the lamp 6 side, a full-wave rectified output is obtained. Thereby, AC lighting which drives the lamp 6 with a negative voltage can be used. One of the thyristors SCR2 and SCR3 may be replaced with a diode.
[0031]
For example, when the lamp is driven by a battery, a sufficient power generation voltage for the battery cannot be obtained at a low idling speed. Therefore, the lamp is mainly driven from the battery, increasing the capacity of the battery and further alternating current. The cost of the entire circuit is increased due to the increased capacity of the generator. On the other hand, by driving the lamp 6 with negative voltage half-wave output, it is not necessary to drive the lamp 6 by the battery 4, and it is not necessary to include the lighting amount of the lamp 6 in the capacity of the battery 4. The alternator 1 can also be reduced in size, and the cost of the entire circuit can be reduced. Furthermore, the preferred lamp lighting without flickering can be realized by the negative voltage full-wave rectification state.
[0032]
When the capacity of the AC generator 1 is the same, the average voltage value can be reduced by half because the coil is divided into two. However, due to the significant reduction in the discharge time, it is simply halved. In other words, the engine control load 8 can be driven. For example, even if it is necessary to increase the capacity of the AC generator 1, it is not necessary to increase the size significantly.
[0033]
In addition, the waveform shown in FIG. 4 can be obtained with the circuit configuration of the example shown in FIG. 1, and can be used as a power supply waveform from the start to idling and normal rotation in that state. For example, each element is controlled separately only at the start. No control circuit is required. Therefore, the circuit can be simplified and the cost of the apparatus can be reduced. Moreover, two diodes can be reduced with respect to the rectifier circuit using four diodes.
[0034]
Although FIG. 1 shows an example in which two diodes D2 and D3 are provided in front of the thyristor SCR1, the full-wave rectification circuit having a positive voltage waveform is not limited thereto, and another example is shown in FIG. . In the figure, the same portions as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
[0035]
In the circuit of FIG. 5, a thyristor SCR4 in parallel with the thyristor SCR1 is provided between the second power input terminal 2e and the node of the thyristor SCR1 and the charging terminal 2b. Even in this case, the positive voltage waveform of the first coil L1 passes through the thyristor SCR1, the positive voltage waveform of the second coil L2 passes through the thyristor SCR4, and is continuously connected to the charging terminal 2b as shown in FIG. A positive voltage waveform is output. Therefore, the same effect as described above can be obtained in this circuit example.
[0036]
【The invention's effect】
As described above, according to the present invention, an output with a positive voltage waveform in the full-wave rectification state is obtained, and the interval between the waveforms is narrowed to about a half compared to that using the positive voltage waveform of the half-wave rectification. When a pseudo-power supply capacitor is installed as a battery replacement in a small motorcycle that starts by kicking, the discharge time is shortened, a high charging voltage is secured, and power is generated at a low rotational speed at the start of kicking. However, sufficient power can be supplied to the positive voltage drive load, and the negative voltage drive load can be driven simultaneously. When a lamp is used as the negative voltage drive load, flicker is prevented.
[0037]
In particular, it is possible to obtain each full-wave rectified waveform of the positive voltage waveform and the negative voltage waveform with a small number of four elements, two each for positive voltage / negative voltage rectification. A power supply circuit that can be simplified and reduced in cost can be provided. In addition, the phase of each waveform output from each coil can be shifted by 180 degrees by a simple structure in which the winding direction of each coil or the magnetization direction of the permanent magnet facing each coil is changed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a power circuit of a small motorcycle to which the present invention is applied.
FIG. 2 is an explanatory diagram showing windings of an AC generator.
FIG. 3 is a view showing an output waveform of each coil.
FIG. 4 is a diagram showing a full-wave rectification state.
FIG. 5 is a view similar to FIG. 1 showing another example.
FIG. 6 shows a conventional power supply circuit.
FIG. 7 is a diagram showing a capacitor potential when a battery voltage is insufficient in a conventional power supply circuit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 AC generator 2 Battery voltage control circuit 3 DC load 4 Battery 5 Battery voltage detection circuit 6 Lamp 7 Lamp voltage detection circuit 8 Engine control load C1 Capacitor D2 / D3 Diode SCR2 / SCR3 Thyristor

Claims (3)

An AC generator driven by an engine, a battery, an engine control load connected to the battery, and a positive voltage drive circuit for charging the battery and driving the engine control load by a positive voltage waveform of the AC generator And a negative voltage driving circuit for driving a negative voltage driving load by a negative voltage waveform of the AC generator,
The AC generator includes a first coil and a second coil configured to output a waveform whose phase is shifted by 180 degrees with respect to the output waveform of the first coil,
The positive voltage driving circuit has positive voltage rectifier circuits connected to the coils so that positive voltage waveforms output from the coils are continuously output to the engine control load;
The negative voltage drive circuit has negative voltage rectifier circuits connected to the coils so that the negative voltage waveforms output from the coils are continuously output to the negative voltage drive load;
Wherein between the positive voltage drive circuit and the engine control load, the full-wave rectification state each positive voltage pseudo power supply capacitor for driving the engine control load by charged and charge-discharge waveform by waveform is provided A power supply circuit for an automobile. The coils are connected in series with each other and the common is grounded;
The positive voltage rectifier circuit has each one-way energization element connected to the output terminal of each coil,
2. The automobile power supply circuit according to claim 1, wherein the negative voltage rectifier circuit includes unidirectional energization elements respectively connected to output terminals of the coils.     The waveforms output from the coils are shifted from each other by 180 degrees by changing the winding direction of the coils or the magnetization direction of the permanent magnet facing the coils. The power supply circuit for an automobile according to claim 1 or 2.

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