JP3161241B2 - Power supply for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for generating a DC output using a magnet generator attached to an internal combustion engine as a power supply.

[0002]

2. Description of the Related Art As a generator mounted on an internal combustion engine,
2. Description of the Related Art A magnet generator including a magnet rotor attached to an output shaft of an engine and a stator fixed to a case or a cover of the engine is often used. Since a magnet generator generates an AC output, a circuit for converting the AC output of the magnet generator to a DC output is required when there is an electrical component that needs to be driven by DC.

When a battery is mounted on a vehicle, a working machine, or the like driven by an internal combustion engine, the battery and a DC load are connected in parallel between output terminals of a generator to reduce the engine speed. While the output voltage of the generator is lower than the terminal voltage of the battery, power is supplied from the battery to the load, and when the output speed of the generator exceeds the terminal voltage of the battery as the engine speed increases, the load is supplied from the generator. Power is supplied to the load. When the battery and the load are connected in parallel between the output terminals of the magnet generator as described above, the magnet generator is required to have characteristics as shown in FIGS. FIG.
5 shows the relation between the output voltage Vo of the generator and the output current Io,
In the figure, VB is a battery voltage, and Ni is an idle speed [rpm].
And there is a relationship of Ni <N1 <N2. FIG.
6 shows the relationship between the charging current Ich of the battery and the engine speed N.

As shown in FIG. 15, when a battery is connected between output terminals of a magnet generator, it is necessary to start charging the battery from the engine idle speed Ni. It is required that the no-load voltage of the magnet generator at Ni is equal to or higher than the battery voltage VB. Further, as shown in FIG. 16, in a region exceeding the idling rotational speed, it is necessary to increase the charging current as the rotational speed increases, and to flow the charging current Ich as large as possible during the steady operation.

In order to allow a large charging current to flow from the magnet generator to the battery during steady operation, it is necessary to lower the impedance of the generating coil of the magnet generator. In order to achieve the above, it is necessary to increase the number of turns of the power generation coil. When the number of turns of the power generation coil is increased, the inductance increases and the winding resistance increases, so that the impedance of the power generation coil increases. In particular, when the space for winding the power generation coil is limited, if the number of turns of the power generation coil is increased, it is necessary to use a coil conductor having a small wire diameter. .

As described above, the requirement to increase the no-load voltage generated at the idle speed and the requirement to increase the charging current flowing to the battery as much as possible are contradictory to the magnet generator. It was very difficult to obtain a power supply.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 59-35538, there has been proposed a power supply device in which a booster circuit is formed by connecting a transistor as a switching element to a power generating coil having a reduced number of turns and a reduced impedance. In this power supply device, a short-circuit current is supplied to the power generation coil by turning on the transistor, energy is stored in the power generation coil, and when the short-circuit current reaches a predetermined value, the transistor is turned off to be stored in the power generation coil. Energy (Li ² ) / 2 [L is the inductance of the winding,
i causes a short-circuit current] to induce a high voltage in the power generation coil.

[0008] According to this power supply device, while the impedance of the generating coil is lowered to secure a large charging current at medium and high speeds, the no-load output voltage of the generator in a relatively low rotation speed region near the idle speed. Even when the voltage does not reach the voltage VB of the battery, the charging current can flow through the battery by the high induced voltage generated when the short-circuit current is cut off.

However, in the power supply device disclosed in JP-A-59-35538, when the output voltage of the power generation coil of the magnet generator exceeds a set value, the power generation coil is short-circuited in addition to the transistor for short-circuiting the power generation coil. Therefore, it is necessary to provide a regulator for preventing the occurrence of overvoltage, so that the structure cannot be avoided.

In the power supply device disclosed in Japanese Patent Application Laid-Open No. 59-35538, the transistor constituting the booster circuit cuts off the short-circuit current only once in each half-wave of the output of the power generation coil. When the voltage is low, generate a voltage large enough to allow the charging current to flow until the short-circuit current is cut off in the next half-wave after the pulse-like voltage induced by the cut-off of the short-circuit current has disappeared in each half-wave. However, there is a problem that the battery cannot be sufficiently charged at a low speed of the engine.

Therefore, as disclosed in JP-A-5-344798 and JP-A-5-344799, a bipolar transistor is used as a switching element for short-circuiting a power generation coil constituting a booster circuit, and the transistor is connected to the power generation coil. The energy (Li ² ) / 2 accumulated in the power generation coil is released when the transistor is turned off, by repeatedly turning on and off in a short cycle regardless of the phase of the induced voltage,
There has been proposed a power supply device in which a high voltage induced in a power generation coil is supplied to a load through a diode bridge full-wave rectifier circuit.

According to such a configuration, in each half-wave of the output of the magnet generator, since the short-circuit and the cut-off of the generating coil are repeated many times, the number of times that the charging current flows to the battery at a low speed of the engine is increased. And the total amount of charging current can be increased. Further, according to the above configuration, by controlling the on-duty ratio of the transistor to decrease with an increase in the output voltage, it is possible to prevent an overvoltage from occurring at a high speed, so that the regulator can be omitted. is there.

[0013]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open No. Hei 5-3
In the power supply apparatus disclosed in Japanese Patent No. 44798 and JP-A-5-344799, as shown in FIG. 14B, when a short circuit of the power generation coil W1 of the magnet generator is formed, rectification is performed on the short circuit. Since one diode Do of the circuit and the circuit between the collector and the emitter of the transistor TRo are connected in series, the output voltage of the magnet generator becomes the collector-emitter saturation voltage VCE of the transistor TRo and the forward voltage of the diode Do. The short-circuit current does not flow unless the threshold voltage Vt corresponding to the sum VCE + VF with the drop VF is exceeded, and the short-circuit current cannot flow in a region where the engine speed is extremely low.

For example, in FIG. 14B, a diode Do is a 20DL2C4 manufactured by Toshiba Corporation.
1A, and 2SC3710 also manufactured by Toshiba Corporation as the bipolar transistor TRo. In this case, the characteristic curve showing the relationship between the forward current and the forward voltage of the diode Do is as shown in FIG.
At a temperature of 25 ° C., Vf> 0.6 [V]. The collector-emitter saturation voltage VCE vs. collector current Ic characteristic of the transistor TRo at the common emitter is shown.
As shown in FIG. 18, when the temperature is 25 ° C., VCE ≧
0.04 [V].

Here, when the speed of the magnet generator is low (100 [rpm])
Output current Io for an output voltage Vo of about 300 [rpm]).
13 is, for example, as shown in FIG. 13. If a load line using the transistor TRo and the diode Do described above is written therein, the characteristic becomes as shown in FIG. That is, in order to make the transistor TRo conductive and cause a short-circuit current to flow to perform the boosting operation, the generator needs to induce a voltage exceeding the threshold voltage Vt = 0.64 [V]. If the output voltage does not reach 0.64 [V], the short-circuit current cannot flow at the number of revolutions, and the booster circuit becomes invalid.

It is conceivable to use a composite transistor connected in Darlington as the transistor TRo.
As shown in FIG. 9, since the collector-emitter saturation voltage further increases, the threshold voltage further increases. FIG. 1
Reference numeral 9 denotes a collector-emitter saturation voltage VCE-collector current Ic characteristic of the Darlington connection transistor 2SD1525 manufactured by Toshiba Corporation when the emitter is grounded.

When a battery is provided on the load side and the battery is sufficiently charged, power can be supplied from the battery side to the electric component load in a region where the engine speed is low. Even if the above-described power supply device in which the circuit does not work is used, the engine can be operated satisfactorily from the start to the high speed.

However, when the above power supply device is used,
Even if a battery is provided, if the battery is over-discharged (goes up), it will not be possible to satisfactorily supply power to the load at low engine speeds. If electrical components indispensable for starting the engine, for example, a fuel pump, an injector (fuel injector), or a control device for these components, it is difficult to start the engine.

That is, when the battery is useless,
Cranking of the engine by rope start using human power (rotating the crankshaft of the engine by external force)
However, it is difficult to increase the number of revolutions of the engine by manual cranking, and a voltage exceeding the threshold voltage Vt is generated in the power generation coil at the time of the start operation to cause a short-circuit current to flow. Since it is not easy to perform the boosting operation, it is difficult to generate a voltage required to drive the fuel pump, the injector, and the like, and the engine may not be able to be started.

Recently, in an internal combustion engine used for a vehicle, a working machine, or the like without a battery, it has been studied to drive a fuel pump, an injector, and a microcomputer for controlling the fuel pump, using a magnet generator attached to the engine as a power source. ing. Also in this case, the impedance is reduced by reducing the number of windings of the power generating coil of the magnet generator, and a booster circuit for short-circuiting and shutting off the power generating coil is provided, so that the power supply device can be operated in an idling rotational speed or more. It is conceivable to increase the load current that can be extracted from the load current. However, also in this case, it is necessary to manually start the engine, and it is unavoidable that starting the engine becomes difficult for the same reason as described above.

When a load such as a fuel pump or an injector is driven by the output of a magnet generator without using a battery,
If the number of turns of the generating coil is sufficiently large, the voltage required to drive the fuel pump and the injector can be obtained when the engine is started manually, but if the number of turns of the generating coil is increased, the impedance of the generating coil becomes large. As a result, it becomes difficult to extract a large load current in a steady operation region equal to or higher than the idling rotation speed, and there is a problem that the load operated during the steady operation is limited.

It is an object of the present invention to provide a power generation coil that operates from an extremely low speed of an engine even when a battery connected in parallel to a load becomes useless due to overdischarge or when the load does not include a battery. It is an object of the present invention to provide a power supply device for an internal combustion engine that can perform a boosting operation by turning on and off a short-circuit current and can drive a load satisfactorily from an extremely low speed to a high speed of the engine.

[0023]

SUMMARY OF THE INVENTION The present invention is a magnet generator driven by an internal combustion engine to generate a single-phase or multi-phase AC voltage between n (n is an integer of 2 or more) output terminals; A rectifier circuit for rectifying an AC voltage obtained between n output terminals of the magnet generator.

In the present invention, the rectifier circuit includes n rectifier diodes and n MOSFETs,
The n rectifying diodes and the MOSFET are respectively formed so that a diode bridge full-wave rectifier circuit is constituted by the n rectifying diodes and a parasitic diode present between the drain and the source of the n MOSFETs. On the same side and a bridge-connected circuit. In the present invention, the n MOSFEs
FE for providing a rectangular wave drive signal of the same phase to the gate of T
A T control circuit is provided, and n M
The OSFET is turned on and off at the same time.

Incidentally, a circuit in which n MOSFETs and n rectifying diodes are bridge-connected corresponds to n M MOSFETs.
By connecting n rectifying diodes in series to the drain-source circuit of the OSFET, n FEs
A T / diode series circuit is formed, and the n FETs /
This is a circuit in which diode series circuits are connected in parallel with the respective MOSFETs and rectifying diodes located on the same side. In this case, in each of the FET / diode series circuits, the MOSFETs are placed so that the direction of the rectifying diode and the direction of the parasitic diode of the MOSFET are the same.
And the direction of the rectifying diode.

In the above configuration, n MOSFETs
Is provided to configure a switch circuit (chopper circuit) for turning on and off the output terminals of the magnet generator. In the present invention, by turning on and off the switch circuit to interrupt the current flowing through the power generation coil of the magnet generator, to induce a boosted voltage in the power generation coil,
This boosted voltage is rectified by a full-wave rectifier circuit using a parasitic diode of a MOSFET as a part of a rectifying element so that a high voltage can be supplied to a load.

In the present invention, when the magnet generator has two output terminals 1a and 1b to generate a single-phase AC output,
For example, as shown in the embodiment of FIG. 1, the rectifier circuit includes first and second rectifying diodes having cathodes connected in common (meaning that the cathodes are connected to each other so as to form the same potential portion). D1 and D2 and N-channel first and second MOSFETs F1 and F2 having drains connected to the anodes of the first and second rectifying diodes and a source connected together, respectively. In this case, a single-phase diode bridge full-wave rectifier circuit is constituted by the first and second rectifying diodes D1 and D2 and the parasitic diodes Df1 and Df2 present between the respective drain sources of the first and second MOSFETs. The single-phase AC output of the magnet generator 1 is input between respective connection points of the anodes of the first and second rectifying diodes and the drains of the first and second MOSFETs. Further, an FET control circuit 3 for providing a rectangular waveform drive signal of the same phase to the gates of the first and second MOSFETs is provided, and the control circuit 3 turns on and off the first and second MOSFETs constituting the switch circuit simultaneously. Let it.

As described above, an N-channel MOSFET
When the rectifier circuit is used, the rectifier circuit also includes first and second rectifier diodes D1 and D2 having anodes connected in common and the first and second rectifier diodes as shown in the embodiment of FIG. It is also possible to use N-channel first and second MOSFETs F1 and F2 in which the source is connected to the cathode and the drain is connected in common. In this case, a single-phase diode bridge full-wave rectifier circuit is constituted by the first and second rectifying diodes D1 and D2 and the parasitic diodes Df1 and Df2 present between the respective drain sources of the first and second MOSFETs. , A single-phase AC output of the magnet generator 1 is input between respective connection points of the cathodes of the first and second rectifying diodes and the sources of the first and second MOSFETs. Also in this case, an FET control circuit 3 for providing a rectangular waveform drive signal having the same phase to the gates of the first and second MOSFETs is provided, and both MOSFETs are simultaneously turned on and off by the control circuit.

In the above example, an N-channel MOSFET is used, but a P-channel MOSFET may be used. P-channel type M
When an OSFET is used, the rectifier circuit is, for example, as shown in FIG.
0, the first and second rectifying diodes D1 and D2 having their anodes connected in common are connected to the first and second rectifying diodes D1 and D2.
And first and second P-channel MOSFETs F1 and F2, whose drains are connected to the cathodes of the second rectifying diodes and whose sources are connected in common, respectively. Also in this case, the first and second rectifier diodes D1 and D2 and the first and second MOSFETs F
A single-phase diode bridge full-wave rectifier circuit is constituted by the parasitic diodes Df1 and Df2 existing between the respective drain and source of F1 and F2, and the cathodes of the first and second rectifier diodes and the first and second MOSFETs. The output of the magnet generator 1 is input between each connection point with the drain of the magnet generator 1. As described above, an FET control circuit 3 is provided which supplies a drive signal in the form of a rectangular wave having the same phase to the gates of the first and second MOSFETs to simultaneously turn on and off both FETs.

In the present invention, when the magnet generator has three output terminals 1a to 1c to generate a three-phase AC output,
For example, as shown in the embodiment of FIG. 5, the rectifier circuit has drains respectively connected to first to third rectifier diodes D1 to D3 whose cathodes are commonly connected and anodes of the first to third rectifier diodes. And N-channel type first to third MOSFETs F1 to F3 whose sources are commonly connected. In this case, the first to third rectifying diodes D1
To D3 and the parasitic diodes Df1 to Df3 of the first to third MOSFETs constitute a three-phase diode bridge full-wave rectifier circuit, wherein the anodes of the first to third rectifier diodes and the first to third MOSFETs are connected. A three-phase AC output obtained between the output terminals 1a to 1c of the magnet generator is input between respective connection points 2u to 2w with the drain. Further, an FET control circuit 3 for providing the same phase rectangular wave driving signal to the gates of the first to third MOSFETs is provided, and the first to third MOs are controlled by the FET control circuit.
The SFET is turned on and off at the same time.

When a three-phase magnet generator is used, FIG.
As in the embodiment shown in FIG.
A rectifier circuit is constituted by the third to third rectifier diodes and the first to third N-channel MOSFETs whose sources are connected to the anodes of the first to third rectifier diodes and whose drains are commonly connected. be able to.

[0032] In the case of using a P-channel type MOSFET, said rectifier circuit, the drains to the cathode of the first to third rectifier diode and the first to third rectifier diode and the anode commonly connected First to third MOSs connected and commonly connected to the source
The three-phase diode bridge full-wave rectifier circuit is constituted by the first to third rectifier diodes and the first to third MOSFET parasitic diodes.

As described above, in the present invention, the MOS
A switch circuit (chopper circuit) for turning on and off the output terminals of the magnet generator is constituted by the FET, and the current flowing through the power generation coil of the magnet generator is turned on and off by the switch circuit to boost the output voltage of the magnet generator. . In the above configuration, when a rectifier circuit for rectifying a three-phase AC voltage is formed, three MOSFETs are provided to form a switch circuit that short-circuits the three-phase power generation coils, thereby forming a three-phase induced voltage. In the present invention, it is sufficient to supply a DC voltage to the load, and the output voltage of the magnet generator boosted by the chopper operation may not have a symmetric waveform. As shown in the embodiment, the switch circuit may be configured to short-circuit only some of the three-phase power generation coils. In the example of FIG. 7, the MOSFETs F1 and F2
A switch circuit for turning on and off between the output terminals 1a and 1b of the magnet generator 1 is configured, and a switch circuit between the output terminals 1b and 1c and 1
A switch circuit for turning on and off between c and 1a is not configured.

In general, when a magnet generator for outputting a multi-phase AC voltage has n output terminals, a MOSFET is formed so as to constitute a switch circuit for short-circuiting between at least two output terminals of the magnet generator. May be provided. In order to configure a switch circuit for short-circuiting between two power generating coils of a magnet generator, two MOSFETs are required. Therefore, when an N-channel MOSFET is positioned on the negative DC output terminal side to form a rectifier circuit for boosting and rectifying a multi-phase AC voltage, the configuration is generalized as follows.

That is, the rectifier circuit used when the magnet generator has n (n is an integer of 3 or more) output terminals is as follows:
The power supply includes m (m is an integer of 2 or more and n or less) MOSFETs whose sources are commonly connected and drains are connected to different output terminals of the magnet generator, and 2 nm m rectifying diodes. 2n-m rectifiers constitute a diode bridge full-wave rectifier circuit that performs full-wave rectification of a polyphase AC voltage with a parasitic diode existing between the drain and source of each MOSFET and 2n-m rectifying diodes. And a m-type MOSFET and a bridge-connected circuit. In this case, the FET control circuit is configured to apply a rectangular waveform drive signal having the same phase to the gates of the m MOSFETs to simultaneously turn on and off the m MOSFETs.

When a rectifier circuit for boosting and rectifying a multi-phase AC voltage by arranging an N-channel MOSFET on the positive DC output terminal side is generalized,
The rectifier circuit includes m (m is an integer of 2 or more and n or less) MOSFETs whose drains are commonly connected and whose sources are connected to different output terminals of the magnet generator, and 2n-m rectifying diodes. And a parasitic diode existing between the drain and source of each of the m MOSFETs and 2n-
2n-m rectifier diodes and m MOSFEs so as to constitute a diode bridge full-wave rectifier circuit for full-wave rectification of a polyphase AC voltage with m rectifier diodes.
It is composed of a circuit in which T is bridge-connected. In this case as well, the FET control circuit gives the same phase rectangular wave drive signal to the gates of the m MOSFETs, and
The ET is configured to be turned on and off at the same time.

In the present invention, the parasitic diode of each MOSFET is used as a part of the rectifying element constituting the full-wave rectifier circuit. In order to increase the current capacity, a parasitic diode is connected between the drain and source of each MOSFET. There is no hindrance to connecting diodes in the same direction in parallel.

[0038]

The operation of the present invention will be described by taking, as an example, a configuration in which the magnet generator generates a single-phase AC output among the configurations described in the above section. In the power supply device configured as described above, as shown in FIG. 14A, a switch circuit for a chopper including two MOSFETs F1 and F2 whose sources are connected in common and connected in series is a magnet power generation device. Connected to both ends of the generator coil W1 of the
When a drive signal is applied to the OSFETs F1 and F2 at the same time, a short circuit of the power generation coil W1 is formed. If both FETs are turned on and off simultaneously by supplying the same rectangular waveform drive signal to the two MOSFETs F1 and F2, both FETs conduct simultaneously with the supply of the drive signal, and short-circuit the generator coil W1 of the magnet generator. The energy of (Li ² ) / 2 is stored in the power generation coil W 1. When the rectangular drive signal disappears, both FETs are simultaneously turned off, so that the short-circuit current flowing through the power generation coil W1 is cut off. At this time, a high voltage is induced in the power generating coil W1 to keep the short-circuit current flowing until now, and this voltage is generated by the first and second diodes D1 and D1.
2 and rectified by a full-wave rectifier circuit composed of parasitic diodes Df1 and Df2 present in the first and second MOSFETs and supplied to a load.

In the power supply device of the present invention, when a drive signal is applied to the first and second MOSFETs, a current flows from the drain side to the source side of one of the FETs.
In the other FET, current flows from the source side to the drain side. In a MOSFET to which a drive signal is applied (a predetermined voltage is applied between the source and the gate), a drain current ID (or a reverse drain current IDR) flows at the same time as the voltage VSD is applied between the source and the drain due to its characteristics. If the source-drain voltage is within a certain range,
A drain current ID (or a reverse drain current IDR) flows almost in proportion to the source-drain voltage VSD. Therefore, the MOSFET to which the drive signal is applied operates in the same manner as the resistor, and in a region where VSD and ID are proportional, the resistance value RDS between the source and the drain in the ON state shows a substantially constant value. Therefore, a circuit in which both ends of the power generation coil are connected through a series circuit of two MOSFETs to which a drive signal is applied is equivalent to a circuit in which both ends of the power generation coil are connected via a resistor, and the drive signal is applied to the two MOSFETs. The load line of the generator in the given state is a straight line passing through the origin as shown in FIG. Therefore, the threshold voltage required to make the FET conductive becomes substantially zero, and when a voltage is slightly induced in the generating coil of the magnet generator, two M
A short-circuit current will flow through the OSFET. Therefore, even when the engine speed is extremely low, such as when the engine is rope-started, if a slight voltage is induced in the power generation coil, a short-circuit current flows through the power generation coil, and FE
When the drive signal of T disappears and the short-circuit current is cut off, a voltage can be induced in the power generation coil.

Therefore, a relatively high DC voltage can be applied to the load even at an extremely low speed of the engine, and the load can be driven from the extremely low speed of the engine, so that the engine using the injector and the fuel injection pump can be used. When the engine is manually started when the battery is over-discharged,
Even when the injector or fuel pump is driven only by the output of the magnet generator without using the battery, the engine can be started without any trouble.

In the above description, the magnet generator generates a single-phase AC output, but the same applies to the case of generating a multi-phase AC output.

[0042]

FIG. 1 shows an embodiment in which a magnet generator generates a single-phase AC output. In FIG. 1, reference numeral 1 denotes a magnet rotor attached to a crankshaft of an internal combustion engine and a case of the engine. And a stator fixed to the magnet generator. A generator coil W1 is provided on the stator of the magnet generator 1, and an AC voltage Ve is induced in the generator coil W1 in synchronization with the rotation of the engine. In the present invention, in order to be able to take out a large current from the power generation coil even when the engine is running at high speed, a power generation coil W1 having a small number of turns and a low impedance is used.

Reference numeral 2 denotes a full-wave rectifier circuit for rectifying an AC voltage induced in the power generation coil W1. The rectifier circuit includes first and second diodes D1 and D2 having cathodes connected in common.
And N-channel first and second MOSFETs having drains connected to the anodes of the first and second diodes D1 and D2, respectively, and a source connected together.
TF1 and F2. In this rectifier circuit, the common connection point of the cathodes of the diodes D1 and D2 and the common connection point of the sources of the MOSFETs F1 and F2 are a positive DC output terminal 2a and a negative DC output terminal 2b, respectively. The terminals are connected to the output terminals 4A and 4B of the power supply to which the load RL is connected. The connection points between the anodes of the first and second diodes D1 and D2 and the drains of the first and second MOSFETs F1 and F2 are AC input terminals 2u and 2v, respectively.
Output terminals 1a and 1b of a generator coil W1 of the generator 1 are connected to u and 2v, respectively. MOSFET F1
And F2 are N-channel type power MOSFETs having parasitic diodes Df1 and Df2 between the drain and the source.
T, the first and second parasitic diodes Df1 and Df2 and the first and second diodes D1 and D2 inherent in the first and second MOSFETs F1 and F2, respectively.
These constitute a single-phase diode bridge full-wave rectifier circuit.

In this example, the MOSFETs F1 and F2
Thus, a chopper switch circuit for turning on and off the output terminals 1a and 1b of the magnet generator is configured. This switch circuit can be represented as shown in FIG.

An FET control circuit 3 for outputting a drive signal VGS is connected between the DC output terminals 2a and 2b of the rectifier circuit 2. This control circuit has output terminals 3a and 3b, the gates of FETs F1 and F2 are commonly connected to one output terminal 3a, and the FETs F1 and F2 are connected to the other output terminal 3b.
A common connection point (negative side DC output terminal) 2b of the sources of F1 and F2 is connected. The FET control circuit 3 oscillates when, for example, a DC power supply voltage is applied, and
(A) An oscillator for generating a rectangular wave signal as shown in FIG. 1 (A), and a rectangular wave signal output from the control circuit 3 is applied as a drive signal VGS between the gate and the source of the first and second MOSFETs. I have. In this embodiment, the MOS
A rectifier circuit 2 is provided to absorb a surge generated in the power generation coil W1 when the FETs F1 and F2 are cut off.
A capacitor Co is connected between the DC output terminals 2a and 2b of the rectifier circuit 2 to smooth the output voltage of the rectifier circuit 2.

In the embodiment of FIG. 1, the FET control circuit 3
Generates a rectangular wave signal having a frequency sufficiently higher than the output frequency of the power generation coil W1, and this rectangular wave signal
Both FETs are driven at the same time by providing the same phase drive signal VGS between the gate and the source of F1 and F2. FET
When a drive signal having a polarity such that the gate is at a positive potential with respect to the source is applied between the gate and source of F1 and F2,
When ET F1 and F2 become conductive and a voltage of a polarity that causes the drain to have a positive potential with respect to the source is applied between the respective drain and source, a drain current flows through both FETs, and a current flows through the generating coil W1. Short circuit current flows. When the drive signal VGS becomes zero, the FETs F1 and F2 are cut off, so that the short-circuit current flowing through the power generation coil W1 is cut off, and the short-circuit current that has been flowing through the power generation coil W1 continues to flow. , The induced voltage Vep (see FIG. 2B) is induced. Due to this voltage, a current Ie as shown in FIG.
Diodes D1 and D2 and parasitic diodes Df1 and Df2
A load current IL as shown in FIG. 2E flows through the load RL through the full-wave rectifier circuit composed of FIG.
(D) shows the waveform of the voltage VL across the load RL.

The MOSFET has a bidirectional property, acts like a resistor when a drive signal is applied, and a drain current ID flows when even a slight voltage VSD is applied between the source and the drain. For example, assuming that 2SK1911 manufactured by Hitachi, Ltd. is used as each MOSFET, the drain-source resistance RDS vs. drain current ID characteristic during conduction is as shown in FIG. 20, and the reverse drain current IDR vs. the source-drain voltage VSD. The characteristics are as shown in FIG. From these, when the drive signal VGS of the polarity in which the source has a positive potential with respect to the gate is applied between the gate and the source of the MOSFET, the drain-source resistance shows a constant value in a wide range, and the drain current and the source-drain It can be seen that there is a substantially proportional relationship with the intermediate voltage VSD, that is, the FET can be regarded as substantially a resistor.

For this reason, two MOSFETs F1 and F2 to which a drive signal is applied are connected to both ends of the power generation coil W1.
The circuit connected through the series circuit (switch circuit) of
It is equivalent to a circuit in which both ends of the generating coil are connected via a resistor, and the load line of the generator in a state where the drive signals are simultaneously applied to the two MOSFETs is a straight line passing through the origin as shown in FIG. Become. Therefore, the threshold voltage required for conducting the MOSFET becomes substantially zero, and if a voltage is slightly induced in the power generation coil of the magnet generator, a short-circuit current flows through the power generation coil W1 through the two MOSFETs F1 and F2. become. Therefore, even when the engine speed is extremely low, such as when the internal combustion engine is rope-started, if a slight voltage is induced in the power generation coil, the MOSFETs F1 and F2 can be turned on to cause a short-circuit current to flow through the power generation coil. Thus, when the drive signals of the MOSFETs F1 and F2 disappear and the short-circuit current is cut off, a boosted voltage can be induced in the power generation coil.

Assume that the magnet generator 1 generates an AC voltage Ve having a no-load voltage waveform as shown in FIG.
FIG. 4 (A) is an enlarged view of the time axis in FIG. 3 showing a waveform near the zero point of the output voltage of the generator (A in FIG. 3).
FIG. 3B shows the waveform of the drive signal VGS applied to the gate of the MOSFET. FIG. 4C shows the waveform of the current Ie flowing through the power generation coil W1. According to the present invention, the current Ie flows even when the voltage Ve is almost zero. Accordingly, a short-circuit current can be supplied to the power generation coil W1 from a state where the induced voltage is extremely low, and even when the engine speed is low, the voltage is induced by interrupting the short-circuit current to drive the load. Can be.

On the other hand, as shown in FIG. 14B, a conventional chopper switch circuit is formed by connecting a collector-emitter circuit of a transistor TRo to both ends of a power generating coil W1 via a diode Do. In the power supply device, as shown in FIG.
Is lower than the threshold voltage Vt, the current Ie '
Therefore, the period during which the short-circuit current can flow is shortened, and the total amount of DC current that can be supplied to the load at an extremely low speed such as when the engine is rope-started decreases.

The curve shown in FIG. 12 shows the change in the cranking speed N of the engine when the rope is pulled to start the engine with the rope. When the conventional power supply device shown in FIG. 14B is used as the chopper switch circuit, a DC current can be supplied to the load only during the period T1 in FIG. The average value of the rotation speed is N2. That is, when the battery is not provided, the power cannot be supplied to the load unless the average value of the cranking speed can be set to N2 by pulling the rope. On the other hand, according to the present invention, the power can be supplied to the load during the entire period of To, T1, and T2 in FIG. 12, and the average value (To, Since the average rotation speed during the period from T2 to T2 can be reduced to N1 (<N2), the start of the engine can be facilitated.

In the present invention, the MOSFET F
It is important that 1 and F2 be turned on and off simultaneously.
If the drive of one MOSFET is delayed, the forward voltage drop of the parasitic diode of the MOSFET whose drive is delayed becomes the threshold voltage of the short circuit, so that the above-described effects cannot be obtained.

When a MOSFET, which is a voltage control element, is used as a switching element for a chopper for short-circuiting and shutting off the power generation coil as described above, the loss caused by the switching element when the power generation coil is short-circuited can be reduced. Therefore, heat generation from the power supply device can be reduced, and the heat sink attached to the switching element can be reduced in size.

FIG. 5 shows an embodiment in which the magnet generator generates three-phase AC output. In this embodiment, the stator of the magnet generator 1 has three-phase power generation coils W1 to W3. These power generating coils are star-connected. Also in this case, the number of windings of the power generation coils W1 to W3 is reduced so that their impedances are sufficiently low. The rectifier circuit 2 includes first to third diodes D1 to D3 whose cathodes are commonly connected, and first to third diodes D1 to D3.
First to third MOS transistors each having a drain connected to the anodes of 1 to D3 and a source connected in common.
FETs F1 to F3, the common connection point of the cathodes of the first to third diodes D1 to D3 and the first connection point.
And a circuit in which the common connection point of the sources of the third to third MOSFETs F1 to F3 is a plus side DC output terminal 2a and a minus side DC output terminal 2b, respectively. The connection points 2u, 2v and 2w between the anodes of the first to third diodes D1 to D3 and the drains of the first to third MOSFETs F1 to F3 are AC input terminals. Terminals 2u, 2v and 2
Output terminals 1a, 1b and 1c on the opposite side of the neutral points of the generating coils W1, W2 and W3 are connected to w. In this example, the MOSFETs F1 to F3 constitute a chopper switch circuit for turning on and off the output terminals 1a, 1b, and 1c of the magnet generator.

Between the output terminals 2a and 2b of the rectifier circuit 2,
An FET control circuit 3 which applies a rectangular waveform drive signal of the same phase to the gates of the first to third MOSFETs F1 to F3 to turn on and off the first to third MOSFETs simultaneously.
The gates and sources of the MOSFETs F1 to F3 are commonly connected to the output terminals 3a and 3b of the control circuit. Each MOSFET is of an N-channel type having a parasitic diode between the drain and the source as in the embodiment of FIG. 1, and includes first to third diodes D1 to D3 and first to third MOSFETs.
By the parasitic diodes Df1 to Df3 of F1 to F3, 3
A phase diode bridge full-wave rectifier circuit is configured.
Other points are the same as those of the embodiment shown in FIG.

In the embodiment shown in FIG. 5, the first to third
MOSFETs F1 to F3 are simultaneously driven by a rectangular-wave-shaped drive signal VGS as shown in FIG. As a result, the short-circuit and interruption of the power generation coils W1 to W3 are repeated, and when the MOSFETs F1 to F3 are interrupted, a boosted voltage is induced in the power generation coils W1 to W3. This voltage is supplied to the load through a full-wave rectifier circuit including rectifying diodes D1 to D3 and parasitic diodes Df1 to Df3. FIG. 6B shows the voltage VL applied to the load RL.
FIG. 6C shows a waveform of the current IL flowing through the load RL.

In each of the above embodiments, the oscillation frequency of the FET control circuit 3 and the duty ratio of the output signal may be constant. However, in order to prevent the output voltage from becoming too high during high-speed rotation of the engine, the output voltage The duty ratio of the drive signal output from the FET control circuit 3 according to the output voltage (= the signal width of the drive signal / the generation period of the drive signal) and / or the frequency of the drive signal so that You may make it control. If the output voltage becomes excessive even when the drive signal is set to zero during high-speed rotation of the engine, a voltage regulator that short-circuits the output of the magnet generator and suppresses an increase in the output voltage can be used together.

In the above embodiment, the FET control circuit 3 is driven by the rectified output of the generator 1. However, when a battery is mounted, the control circuit 3 is driven by the battery. It may be. When a battery is not mounted, the FET control circuit 3 may be driven using a simple battery such as a dry battery.

In the above embodiment, the three-phase AC voltage is boosted,
In order to configure a rectifier circuit for rectification, three MOSFETs
The switch circuit is configured so that T is provided to turn on and off the three output terminals of the magnet generator. However, the switch circuit is configured to turn on and off only some of the output terminals of the magnet generator. You can also. FIG. 7 shows the embodiment. In this example, the first and second MOs are shown.
SFETs F1 and F2 and four rectifying diodes D
The rectifier circuit 2 is constituted by 1 to D3 and D3 '. The configuration of this rectifier circuit is the same as that of the embodiment shown in FIG.
This is equivalent to replacing the SFET F3 with a diode D3 '.

In the case of the configuration shown in FIG.
Since only the current flowing through a part of the generator coils W1 and W2 of the magnet generator is turned on and off by turning on and off the ET F1 and F2, the output voltage of the magnet generator has an asymmetric waveform. The current is rectified, smoothed by the capacitor Co, and supplied to the load RL, so that driving of the load is not hindered.

In the above embodiment, the rectifier circuit is constructed by connecting the sources of the MOSFETs in common, connecting the drains to the anodes of the corresponding rectifying diodes, and positioning the MOSFETs on the negative DC output terminal side of the rectifier circuit. But
The MOSFET may be connected so that the direction of the parasitic diode is the same as the direction of the rectifying diode, and is not limited to the connection in the above embodiment. For example, as shown in FIG. 8, the drains of the first and second MOSFETs F1 and F2 are commonly connected, and the respective sources are connected to the cathodes of diodes D1 and D2 whose anodes are commonly connected. Two MOSFETs may be located on the positive DC output terminal side of the rectifier circuit. However, in this case, in order to turn on the MOSFETs F1 and F2, as shown in FIG.
, It is necessary to apply a gate voltage higher than the drain potential VL.

In the example of FIG. 8, the rectifier circuit 2 rectifies a single-phase AC output. However, even when a rectifier circuit for rectifying a three-phase AC output is configured, the MOSFET is connected to the positive DC output terminal side. It can be configured to be positioned. That is,
By providing first to third MOSFETs F1 to F3 and first to third rectifying diodes D1 to D3,
And the drains of the third to third MOSFETs are commonly connected to the positive DC output terminal of the rectifier circuit, and the sources of the first to third MOSFETs F1 to F3 are connected in common to the anodes connected to the negative DC output terminal. It is also possible to adopt a configuration in which the diodes are connected to the cathodes of the first to third rectifying diodes D1 to D3, respectively.

As shown in FIG. 7, even when a switch circuit that turns on and off only a part of the output terminals of the magnet generator is constituted by MOSFETs smaller than the number of output terminals of the polyphase magnet generator, Can be provided on the positive DC output terminal side.

In general, in order to construct a rectifier circuit that has n (n is an integer of 3 or more) output terminals and rectifies and boosts the output of a magnet generator that outputs a polyphase AC voltage, it is necessary to use a magnet generator. The switch circuit may be configured to short-circuit between at least two output terminals of the device. In order to configure a switch circuit for short-circuiting between two power generating coils of a magnet generator,
Two MOSFETs are required. Therefore, the rectifier circuit for boosting and rectifying the multi-phase AC voltage with the N-channel MOSFET positioned on the negative DC output terminal side has a common source and a drain connected to different output terminals of the magnet generator. MOSFETs (m is an integer from 2 to n)
And 2 nm rectifying diodes, and a full-wave rectification of the multi-phase AC voltage is performed by the parasitic diodes existing between the respective drain sources of the m MOSFETs and 2 nm rectifying diodes. In order to constitute a diode bridge full-wave rectifier circuit, it can be constituted by a circuit in which 2n-m rectifying diodes and m MOSFETs are bridge-connected. In this case, the FET control circuit has m M
A drive signal in the form of a rectangular wave having the same phase is supplied to the gate of the OSFET to turn on and off the m MOSFETs at the same time.

A rectifier circuit for boosting and rectifying a multi-phase AC voltage by placing an N-channel MOSFET on the positive DC output terminal side has a drain connected in common and a source connected to different output terminals of the magnet generator. M (m is 2 or more and n
The following integer) MOSFETs and 2 nm rectifying diodes, and a parasitic diode existing between the respective drain sources of the m MOSFETs and 2 nm
2n-m rectifier diodes and m MOSFEs so as to constitute a diode bridge full-wave rectifier circuit for full-wave rectification of the multi-phase AC voltage with the rectifier diodes.
It can be constituted by a circuit in which T and T are bridge-connected.

In the above embodiment, each MOSFET is off when the potential of the gate with respect to the source is 0 volt, and is on when a drive signal for setting the gate potential to the positive potential is applied to the source. N-channel type is used, but the P-channel is turned on when the gate potential is 0 volt, and turned off when a drive signal for making the gate potential positive with respect to the source is applied. Shaped MOSFETs can also be used.

FIG. 10 shows an embodiment in which a P-channel type MOSFET is used. In this example, the sources of P-channel type first and second MOSFETs F1 and F2 are commonly connected, and The anodes of the first and second rectifying diodes D1 and D2 are commonly connected, and
The drains of SFETs F1 and F2 are connected to the cathodes of diodes D1 and D2, respectively. MOSFET
Parasitic diodes of F1 and F2 and rectifying diode D1
And D2 constitute a single-phase diode bridge full-wave rectifier circuit.

In this embodiment, in order to turn off the MOSFETs F1 and F2, as shown in FIG.
A gate voltage higher than the potential VL of the sources (plus output terminals of the rectifier circuits) of the OSFETs F1 and F2 is required.

[0069] In this case, the source is commonly connected with the respective drains to the cathode of the first to third rectifier diode D1 to D3 and the first to third rectifier diode having an anode connected in common is connected P-channel type first to third MOSFETs F1 to F3
Thus, a rectifier circuit for boosting and rectifying the three-phase AC output can be formed.

When a rectifier circuit for rectifying a polyphase AC output voltage using a P-channel type MOSFET is also constructed,
As in the case of using the N-channel type MOSFET, a MOSFET having a smaller number of output terminals than the number of the output terminals of the magnet generator so as to turn on and off only a part of the output terminals of the magnet generator.
A switch circuit can be configured by T.

Generally, a rectifier circuit that boosts and rectifies a polyphase AC voltage obtained from a magnet generator that generates a polyphase AC voltage between n output terminals (n is an integer of 3 or more) and outputs a DC voltage is , A P-channel MOSFET (m is an integer of 2 or more and n or less) having a source connected in common and a drain connected to different output terminals of the magneto-generator;
m rectifier diodes and m MOSFEs
The m MOSFETs and m MOSFETs are configured to form a diode bridge full-wave rectifier circuit that performs full-wave rectification of the polyphase AC output voltage with a parasitic diode existing between each drain and source of T and 2 nm rectifying diodes. It can be configured by a circuit in which 2n-m rectifying diodes are bridge-connected.

The preferred embodiments of the present invention have been described above. The main aspects of the present invention disclosed in this specification are as follows.

(1) A magnet generator driven by an internal combustion engine to generate a single-phase or multi-phase AC voltage between n (n is an integer of 2 or more) output terminals, and n of the magnet generator
A power supply device for an internal combustion engine, comprising: a rectifier circuit for rectifying an AC voltage obtained between the output terminals; wherein the rectifier circuit includes n rectifier diodes and n MOSFETs; Rectifier diode and n MOSFETs
A circuit in which the n rectifier diodes and the MOSFET are bridge-connected with each other on the same side so that a diode bridge full-wave rectifier circuit is constituted by a parasitic diode present between each drain and source of T. A switch circuit for turning on and off between the n output terminals of the magnet generator by the n MOSFETs, and providing a drive signal in the form of a rectangular wave having the same phase to the gates of the n MOSFETs. The n MOSFEs
A power supply device for an internal combustion engine, comprising an FET control circuit for turning on and off T at the same time.

(2) In a power supply device for an internal combustion engine which outputs a DC voltage by full-wave rectifying a single-phase AC output voltage of a magnet generator driven by the internal combustion engine, a source is commonly connected and a drain is connected to the magnet power generation device. A switch circuit comprising N-channel first and second MOSFETs connected to different output terminals of the machine; and the first and second MOSFETs
Diode bridge full-wave rectifier, which is composed of a parasitic diode existing between the respective drain sources and the first and second rectifying diodes, and full-wave rectifies an AC voltage obtained between output terminals of the magnet generator. A power supply apparatus for an internal combustion engine, comprising: a circuit; and a FET control circuit that supplies a drive signal of a rectangular waveform having the same phase to the gates of the first and second MOSFETs to turn on and off the two MOSFETs at the same time.

(3) In a power supply device for an internal combustion engine which outputs a DC voltage by full-wave rectifying a single-phase AC output voltage of a magnet generator driven by the internal combustion engine, a drain is connected in common and a source is connected to the magnet power generation device. A switching circuit composed of first and second MOSFETs respectively connected to different output terminals of the device, a parasitic diode existing between the respective drain sources of the first and second MOSFETs, and first and second rectifiers. A diode bridge full-wave rectifier circuit configured by a diode to perform full-wave rectification of an AC voltage obtained between output terminals of the magnet generator; and a rectangular-wave-shaped drive having the same phase at the gates of the first and second MOSFETs. FE that gives a signal to turn on and off both MOSFETs at the same time
A power supply device for an internal combustion engine, comprising a T control circuit.

(4) In a power supply device for an internal combustion engine that outputs a DC voltage by full-wave rectifying a single-phase AC output voltage of a magnet generator driven by the internal combustion engine, a source is commonly connected, and a drain is connected to the magnet power generation device. P-channel type first and second MOSFs respectively connected to different output terminals of the device
A switch circuit made of ET, and the first and second MOs.
A diode bridge full-wave rectifier circuit configured by a parasitic diode existing between each drain and source of the SFET and first and second rectifier diodes to perform full-wave rectification of an AC voltage obtained between output terminals of the magnet generator. When,
A power supply device for an internal combustion engine, comprising: an FET control circuit that applies a rectangular waveform drive signal having the same phase to the gates of the first and second MOSFETs to simultaneously turn on and off the two MOSFETs.

(5) In a power supply device for an internal combustion engine which outputs a DC voltage by full-wave rectifying a three-phase AC output voltage of a magnet generator driven by the internal combustion engine, a source is commonly connected, and a drain is provided by the magnet power generation device. N-channel first to third MOSs respectively connected to different output terminals of the device
A switching circuit composed of an FET, a parasitic diode existing between the drain and source of each of the first to third MOSFETs, and a first to third rectifying diode, between the output terminals of the magnet generator; A diode bridge full-wave rectifier circuit for full-wave rectification of the obtained three-phase AC voltage; and a first-third MOSFET having the same phase rectangular-wave drive signal applied to the gates of the first to third MOSFETs to drive the first-third MOSFET. A power supply device for an internal combustion engine, comprising: a FET control circuit for turning on and off at the same time.

(6) In a power supply device for an internal combustion engine which outputs a DC voltage by full-wave rectifying a three-phase AC output voltage of a magnet generator driven by the internal combustion engine, a source is commonly connected, and a drain is provided by the magnet power generation device. P-channel first to third MOSs respectively connected to different output terminals of the device
A three-phase switch circuit comprising an FET, a parasitic diode existing between the drain and source of each of the first to third MOSFETs, and a first to third rectifying diode, and obtained from the magnet generator. A diode-bridge full-wave rectifier circuit for full-wave rectification of an AC voltage; and a first-to-third M-wave drive signal given to the gates of the first to third MOSFETs by applying a drive signal of a rectangular waveform having the same phase.
A power supply device for an internal combustion engine, comprising a FET control circuit for turning on and off an OSFET simultaneously.

(7) A polyphase obtained between the n output terminals of a magnet generator driven by an internal combustion engine to generate a polyphase AC voltage between n (n is an integer of 3 or more) output terminals In an internal combustion engine power supply device that rectifies an AC voltage and outputs a DC voltage, an N-channel type m (m is 2 or more and n or more) having a source connected in common and a drain connected to different output terminals of the magnet generator Switch circuit consisting of MOSFETs of the following integers), a parasitic diode existing between the drain and source of each of the m MOSFETs, and 2
a diode bridge full-wave rectifier circuit composed of nm rectifying diodes for full-wave rectification of the multi-phase AC output voltage of the magnet generator; A drive signal is given to the m M
A power supply device for an internal combustion engine, comprising: a FET control circuit for simultaneously turning on and off an OSFET.

(8) A polyphase obtained between the n output terminals of a magnet generator driven by an internal combustion engine to generate a polyphase AC voltage between n (n is an integer of 3 or more) output terminals In an internal combustion engine power supply device that rectifies an AC voltage and outputs a DC voltage, an N-channel type m (m is 2 or more and n is an n-channel type) having a drain commonly connected and a source connected to different output terminals of the magnet generator Switch circuit consisting of MOSFETs of the following integers), a parasitic diode existing between the drain and source of each of the m MOSFETs, and 2
a diode bridge full-wave rectifier circuit composed of mn rectifying diodes for full-wave rectification of the multi-phase AC output voltage of the magnet generator; A drive signal is given to the m M
A power supply device for an internal combustion engine, comprising: a FET control circuit for simultaneously turning on and off an OSFET.

(9) A polyphase obtained between the n output terminals of a magnet generator driven by an internal combustion engine to generate a polyphase AC voltage between n (n is an integer of 3 or more) output terminals In a power supply device for an internal combustion engine which rectifies an AC voltage and outputs a DC voltage, a P-channel type m (m is 2 or more and n or more) having a source connected in common and a drain connected to different output terminals of the magnet generator Switch circuit consisting of MOSFETs of the following integers), a parasitic diode existing between the drain and source of each of the m MOSFETs, and 2
a diode bridge full-wave rectifier circuit composed of mn rectifying diodes for full-wave rectification of the multi-phase AC output voltage of the magnet generator; A drive signal is given to the m M
A power supply device for an internal combustion engine, comprising: a FET control circuit for simultaneously turning on and off an OSFET.

[0082]

As described above, according to the present invention, at least two outputs of the magnet generator are generated by the plurality of MOSFETs having the same relationship between the applied voltage and the flowing current as when a voltage is applied to the resistor. A bridge full-wave rectifier circuit is formed by turning on and off the terminals, and a bridge full-wave rectifier circuit is formed by a parasitic diode existing between the drain and source of the MOSFET and another rectifying diode.
The same phase drive signal is applied to the plurality of MOSFETs to turn on and off simultaneously, thereby turning on and off the output terminals of the magnet generator to boost the output voltage of the magnet generator. The threshold value of the applied voltage required for flowing the current can be made substantially zero, and from a state where the output voltage of the generator is extremely low, a short-circuit current can be supplied to the power generation coil through the MOSFET to perform the boosting operation.
There is an advantage that power can be supplied to the load even at extremely low speeds of the engine.

According to the present invention, there is provided an MO having a parasitic diode as a switching element for short-circuiting a power generation coil.
Since the full-wave rectifier circuit is configured using the SFET and the parasitic diode of the MOSFET, the circuit configuration can be simplified.

Further, according to the present invention, since the MOSFET which is the voltage control element is used as the short-circuiting switching element, the loss generated in the switching element when the power generation coil is short-circuited can be made small, and the switching element generates a short-circuit. There is an advantage that heat generation can be suppressed and the heat sink can be downsized.

[Brief description of the drawings]

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

FIG. 2 is a waveform diagram showing signal waveforms at various parts in FIG.

FIG. 3 is a waveform diagram showing an example of a no-load output voltage waveform of a magnet generator.

FIG. 4 is a waveform diagram for explaining a difference in operation between a case where an FET is used as a switching element for short-circuiting a power generation coil and a case where a bipolar transistor is used.

FIG. 5 is a circuit diagram showing another embodiment of the present invention.

6 is a signal waveform diagram of each part in the embodiment of FIG.

FIG. 7 is a circuit diagram showing still another embodiment of the present invention.

FIG. 8 is a circuit diagram showing still another embodiment of the present invention.

FIG. 9 is a waveform diagram showing a drive signal of the FET used in the embodiment of FIG.

FIG. 10 is a circuit diagram showing still another embodiment of the present invention.

11 is a waveform chart showing a drive signal of the FET used in the embodiment of FIG.

FIG. 12 is a diagram showing a change in cranking speed when the engine is manually started.

FIG. 13 is a diagram showing output voltage-output current characteristics of a magnet generator together with load lines.

FIG. 14A is a circuit diagram showing a short circuit of a power generation coil according to an embodiment of the present invention. (B) is a circuit diagram showing a short circuit of a power generation coil in a conventional power supply device.

FIG. 15 is a diagram showing an example of an output voltage-output current characteristic required for a magnet generator mounted on an internal combustion engine equipped with a battery.

FIG. 16 is a diagram showing an example of a desirable relationship between a charging current of a battery and an engine speed.

FIG. 17 is a diagram showing an example of a forward current vs. forward voltage characteristic of a diode.

FIG. 18 is a diagram showing a collector-emitter saturation voltage-collector current characteristic of a certain transistor.

FIG. 19 is a diagram showing a collector current characteristic with respect to a collector-emitter saturation voltage of another transistor.

FIG. 20 is a diagram showing an example of drain-source resistance-drain current characteristics when the MOSFET is conducting.

FIG. 21 is a diagram showing reverse drain current vs. source-drain voltage characteristics of the same MOSFET as in FIG. 20;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnet generator 1a-1c Output terminal W1-W3 Generating coil 2 Rectifier circuit D1-D3 First-third rectifier diode F1-F3 First-third MOSFET Df1-Df3 First-third parasitic diode 3 FET control circuit RL load

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-35538 (JP, A) JP-A-62-144542 (JP, A) JP-A-5-344798 (JP, A) JP-A-5-344798 344799 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02J ^7/ 14-7/24 H02P 9/00-9/48

Claims (7)

(57) [Claims] An internal combustion engine driven by n (n is 2)
A magnet generator that generates a single-phase or multi-phase AC voltage between the output terminals of the above (integer), and a rectifier circuit that rectifies the AC voltage obtained between the n output terminals of the magnet generator. In the power supply device for an internal combustion engine, the rectifier circuit includes n rectifier diodes and n MO diodes.
SFETs and the n rectifier diodes so that a diode bridge full-wave rectifier circuit is constituted by the n rectifier diodes and a parasitic diode present between the drain and source of each of the n MOSFETs. And M
An OSFET and a circuit in which each is positioned on the same side and bridge-connected, and a FET control circuit for supplying a drive signal in the form of a rectangular wave having the same phase to the gates of the n MOSFETs to simultaneously turn on and off the n MOSFETs A power supply device for an internal combustion engine, comprising: 2. A power supply device for an internal combustion engine, comprising: a magnet generator driven by an internal combustion engine; and a rectifier circuit for full-wave rectifying a single-phase AC output of the magnet generator, wherein the rectifier circuit has a cathode. N-channel first and second N-channel rectifier diodes having drains connected to anodes of the first and second rectifier diodes connected in common and anodes of the first and second rectifier diodes, respectively, and having a source connected in common.
Comprising a single-phase diode bridge full-wave rectifier circuit including first and second rectifying diodes and a parasitic diode present between the drain and source of each of the first and second MOSFETs. And a single-phase AC output of the magnet generator is input between respective connection points of the anodes of the first and second rectifying diodes and the drains of the first and second MOSFETs. A power supply device for an internal combustion engine, comprising: an FET control circuit that applies a rectangular waveform drive signal to the gate of the second MOSFET to turn on and off both MOSFETs at the same time. 3. A power supply device for an internal combustion engine, comprising: a magnet generator driven by an internal combustion engine; and a rectifier circuit for performing full-wave rectification on a single-phase AC output of the magnet generator. N-channel first and second N-channel rectifier diodes having a source connected to the commonly connected first and second rectifier diodes and a cathode connected to each of the first and second rectifier diodes and a drain connected together.
Comprising a single-phase diode bridge full-wave rectifier circuit including first and second rectifying diodes and a parasitic diode present between the drain and source of each of the first and second MOSFETs. And a single-phase AC output of the magnet generator is input between respective connection points of the cathodes of the first and second rectifying diodes and the sources of the first and second MOSFETs. A power supply device for an internal combustion engine, comprising: an FET control circuit that applies a rectangular waveform drive signal to the gate of the second MOSFET to turn on and off both MOSFETs at the same time. 4. A power supply device for an internal combustion engine, comprising: a magnet generator driven by an internal combustion engine; and a rectifier circuit for performing full-wave rectification of a single-phase AC output of the magnet generator. P-channel first and second P-channel type commonly connected first and second rectifying diodes, and drains connected to the cathodes of the first and second rectifying diodes, respectively, and sources connected together.
Comprising a single-phase diode bridge full-wave rectifier circuit including first and second rectifying diodes and a parasitic diode present between the drain and source of each of the first and second MOSFETs. And a single-phase AC output of the magnet generator is input between respective connection points between the cathodes of the first and second rectifying diodes and the drains of the first and second MOSFETs. And an FET control circuit for supplying a drive signal in the form of a rectangular wave having the same phase to the gate of the second MOSFET to turn on and off both FETs at the same time. 5. A power supply device for an internal combustion engine, comprising: a magnet generator driven by an internal combustion engine; and a rectifier circuit for full-wave rectifying a three-phase AC output of the magnet generator, wherein the rectifier circuit has a cathode. N-channel first to third rectifier diodes having drains connected to the anodes of the first to third rectifier diodes connected in common and the anodes of the first to third rectifier diodes and having a source connected in common. A three-phase diode bridge full-wave rectifier circuit including a first to a third rectifier diode and a parasitic diode of the first to third MOSFETs. Of the rectifier diode and the first to third MOSs
A three-phase AC output of the magnet generator is input between respective connection points with the drain of the FET, and a drive signal of an in-phase rectangular wave is given to the gates of the first to third MOSFETs to provide the first to third gates. Or the third MOS
A power supply device for an internal combustion engine, comprising an FET control circuit for turning on and off the FET simultaneously. 6. A power supply device for an internal combustion engine, comprising: a magnet generator driven by an internal combustion engine; and a rectifier circuit for full-wave rectifying a three-phase AC output of the magnet generator. P-channel first to third rectifier diodes in which the drains are connected to the commonly connected first to third rectifier diodes and the cathodes of the first to third rectifier diodes and the sources are connected together. A three-phase diode bridge full-wave rectifier circuit comprising a first to a third rectifier diode and a parasitic diode of the first to third MOSFETs. Cathode of rectifier diode and first to third MOSFETs
A three-phase AC output of the magnet generator is input between each connection point with the drain of T, and a drive signal in the form of a rectangular wave having the same phase is given to the gates of the first to third MOSFETs, thereby the first Or the third MOS
A power supply device for an internal combustion engine, comprising an FET control circuit for turning on and off the FET simultaneously. 7. An engine driven by an internal combustion engine, wherein n (n is 3)
An internal combustion engine comprising: a magnet generator that generates a polyphase AC voltage between the output terminals of the above (integer); and a rectifier circuit that rectifies the polyphase AC voltage obtained between n output terminals of the magnet generator. In the power supply device for m, the rectifier circuit includes m (m is 2) having a source connected in common and a drain connected to different output terminals of the magnet generator.
(N is an integer of n or less) and 2n-m rectifying diodes, and a parasitic diode existing between the drain and source of each of the m MOSFETs and the 2n-m rectifying diodes. A diode bridge full-wave rectifier circuit for full-wave rectification of the polyphase AC voltage, a bridge-connected circuit of the 2n-m rectifier diodes and m MOSFETs, and the m MOSFETs A power supply device for an internal combustion engine, which is provided with an FET control circuit that supplies a drive signal in the form of a rectangular wave to the gates of the transistors and turns on and off the m MOSFETs simultaneously.