JPH0833228A - Power supply for internal-combustion engine - Google Patents

Abstract

PURPOSE:To obtain a power supply for an internal-combustion engine which can feed DC power to a load even when the r.p.m. of engine is quite low. CONSTITUTION:Diodes D1, D2 and MOSFETs F1, F2 are connected in a bridge to constitute a rectifier circuit 2 which is applied, between the AC input terminals 2u, 2v thereof, with the AC output from a magnet generator 1. A load RL is connected between the output terminals of the rectifier circuit 2. An FET control circuit 3 turns both FETs F1, F2 ON/OFF simultaneously by applying in-phase drive signals thereto.

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 direct current output by using a magnet generator installed in 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 Magnetogenerators that include a magnet rotor attached to an output shaft of an engine and a stator fixed to a case or cover of the engine are often used. Since the magneto generator generates an AC output, if there is an electrical component that needs to be driven by DC, a circuit that converts the AC output of the magnet generator into a DC output is required.

When a battery is mounted on a vehicle or a working machine driven by an internal combustion engine, the battery and a DC load are connected in parallel between the output terminals of the generator so that the engine speed is low. 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 voltage of the generator exceeds the terminal voltage of the battery by increasing the engine speed, Power is supplied to the load. When the battery and the load are connected in parallel between the output terminals of the magnet generator in this way, the magnet generator is required to have the characteristics shown in FIGS. 15 and 16. FIG.
5 shows the relationship between the output voltage Vo and the output current Io of the generator,
The rotation speed N is shown as a parameter. In the figure, VB is the battery voltage, and Ni is the idle rotation speed [rpm.
], And there is a relationship of Ni <N1 <N2. See also FIG.
6 shows the relationship between the charging current Ich of the battery and the engine speed N.

As shown in FIG. 15, when the battery is connected between the output terminals of the magnet generator, it is necessary to start charging the battery from the idle speed Ni of the engine. It is required that the no-load voltage of the magneto generator at Ni be above the battery voltage VB. In addition, as shown in FIG. 16, in the region where the engine speed exceeds the idle speed, it is necessary to increase the charging current as the engine speed increases so that the charging current Ich is as large as possible during steady operation.

In order to allow a large charging current to flow from the magneto generator to the battery during steady operation, it is necessary to lower the impedance of the magneto coil of the magneto generator, but the no-load voltage at idle speed is the battery voltage. To achieve the above, it is necessary to increase the number of turns of the power generating coil. When the number of turns of the magneto coil is increased, the inductance is increased and the winding resistance is increased, so that the impedance of the magneto coil is increased. Especially when there is a restriction on the space around which the power generating coil is wound, if the number of windings of the power generating coil is increased, it is necessary to use a coil conductor having a small wire diameter, so that the winding resistance increases significantly. .

As described above, the demand for increasing the no-load voltage generated at the idle speed and the demand for maximizing the charging current flowing through the battery are contradictory to the magnet generator, and therefore satisfy both of them. Obtaining a power supply was quite difficult.

Therefore, as disclosed in Japanese Patent Laid-Open No. 59-35538, there has been proposed a power supply device in which a booster circuit is constructed by connecting a transistor as a switching element to a power generation coil having a reduced number of turns and a reduced impedance. In this power supply device, a short-circuit current is caused to flow in the power-generating coil by making the transistor conductive, and energy is accumulated in the power-generating coil. When the short-circuit current reaches a predetermined value, the transistor is shut off and stored in the power-generating coil. Energy (Li ² ) / 2 [L is the inductance of the winding,
i is a short circuit current] to induce a high voltage in the generator coil.

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

However, in the power supply device of Japanese Patent Laid-Open No. 59-35538, the generator coil is short-circuited when the output voltage of the generator coil of the magnet generator exceeds the set value in addition to the transistor for short-circuiting the generator coil. Since it is necessary to provide a regulator to prevent the occurrence of overvoltage, it is unavoidable that the structure becomes complicated.

Further, in the power supply device of Japanese Patent Laid-Open No. 59-35538, since the transistor constituting the booster circuit cuts off the short-circuit current only once in each half-wave of the output of the generator coil, the rotational speed of the engine is high. When it 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-shaped voltage induced by the cut-off of the short-circuit current in each half-wave disappears. However, there was a problem that the battery could not be fully charged when the engine speed was low.

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 generating coil which constitutes a booster circuit, and the transistor is connected to the power generating coil. It is repeatedly turned on and off at a short cycle regardless of the phase of the induced voltage to release the energy (Li ² ) / 2 accumulated in the magneto coil when the transistor is off,
At that time, a power supply device has been proposed in which a high voltage induced in the generator 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, the short-circuiting and the interruption of the power-generating coil are repeated many times, so that the number of times the charging current flows through the battery at a low speed of the engine can be increased. Therefore, the total amount of charging current can be increased. Further, according to the above configuration, since the on-duty ratio of the transistor is controlled to be small as the output voltage rises, it is possible to prevent an overvoltage from occurring at a high speed, so that the regulator can be omitted. is there.

[0013]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the power supply devices shown in Japanese Patent No. 44798 and Japanese Patent Laid-Open No. 5-344799, when a short circuit of the power generation coil W1 of the magnet generator is constructed, as shown in FIG. Since one diode Do of the circuit and the collector-emitter circuit of the transistor TRo are connected in series, the output voltage of the magnet generator is the collector-emitter saturation voltage VCE of the transistor TRo and the forward voltage of the diode Do. There is a problem that the short-circuit current does not flow unless the threshold voltage Vt corresponding to the sum VCE + VF of the drop VF is exceeded, and the short-circuit current cannot flow in the extremely low engine speed region.

For example, in FIG. 14B, 20DL2C4 manufactured by Toshiba Corporation as a diode Do.
It is assumed that 1A is used and 2SC3710 manufactured by Toshiba Corporation is used 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 characteristics of the collector-emitter saturation voltage VCE vs. collector current Ic in the grounded emitter of the transistor TRo are as follows:
As shown in FIG. 18, when the temperature is 25 ° C., VCE ≧
It becomes 0.04 [V].

Here, at low speed of the magnet generator (100 [rpm]
Output current Io for output voltage Vo of 300 to 300 [rpm])
13 is shown, for example, as shown in FIG. 13. When the load line in the case of using the transistor TRo and the diode Do is written in the characteristic, the line B in FIG. 13 is obtained. That is, in order to make the transistor TRo conductive and to flow the short-circuit current to perform the boosting operation, the generator needs to induce a voltage exceeding the threshold voltage Vt = 0.64 [V]. Since the short-circuit current cannot flow at a rotation speed at which the output voltage of 6 does not reach 0.64 [V], the booster circuit becomes invalid.

It is also possible to use a compound transistor connected in Darlington as the transistor TRo.
As shown in FIG. 9, the collector-emitter saturation voltage is further increased, so that the threshold voltage is further increased. FIG. 1
9 shows the characteristics of the collector-emitter saturation voltage VCE vs. collector current Ic when the emitter of the Darlington connection transistor 2SD1525 manufactured by Toshiba Corporation is grounded.

When a battery is provided on the load side and the battery is sufficiently charged, electric power can be supplied from the battery side to the electrical component load in a region where the engine speed is low, so that boosting is performed at low speed. The engine can be satisfactorily operated from the time of starting to the time of high speed even if the above power supply device in which the circuit does not work is used.

However, when the above power supply device is used,
Even if a battery is provided, if the battery becomes over-discharged (if it goes up), it will not be possible to satisfactorily supply power to the load at low engine speeds. In the case where electric components essential for starting the engine, such as a fuel pump, an injector (fuel injector), or a control device for these, are included, it becomes difficult to start the engine.

That is, when the battery is useless,
Cranking the engine by starting the rope using human power (rotating the crankshaft of the engine by an external force)
However, it is difficult to increase the rotational speed of the engine in the cranking by human power, and a voltage exceeding the threshold voltage Vt is generated in the generator coil at the time of the starting operation so that the short-circuit current flows. Since it is not easy to perform the boosting operation, it is difficult to generate the voltage necessary for driving the fuel pump, the injector, etc., and it may not be possible to start the engine.

Further, recently, in an internal combustion engine used in a vehicle, a work machine or the like without a battery, it has been considered to drive a fuel pump, an injector and a microcomputer for controlling them by using a magnet generator attached to the engine as a power source. ing. Also in this case, the impedance is lowered by reducing the number of turns of the magneto coil of the magneto generator, and a booster circuit that short-circuits and cuts off the magneto coil is provided, so that the power supply device can operate in the region of idling speed or more. It is conceivable to increase the load current that can be taken out from. However, also in this case, since it is necessary to manually start the engine, it is inevitable that the engine will be difficult to start for the same reason as described above.

When a load such as a fuel pump or an injector is driven by the output of the magnet generator without using a battery,
If the number of turns of the generator coil is set sufficiently large, the voltage required to drive the fuel pump and the injector can be obtained when the engine is started by human power.However, if the number of turns of the generator coil is increased, the impedance of the generator coil is increased. Since it becomes large, it becomes difficult to take out a large load current in a steady operation region of idling speed or more, and there is a problem that the load operated during steady operation is limited.

It is an object of the present invention to operate the generator coil from the very low speed of the engine even when the battery connected in parallel to the load becomes useless due to over discharge or when the load does not include the battery. It is an object of the present invention to provide a power supply device for an internal combustion engine, which can perform a boosting operation by turning on / 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 that is 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. The present invention relates to a power supply device for an internal combustion engine, which comprises a rectifier circuit that rectifies an AC voltage obtained between n output terminals of the magnet generator.

In the present invention, the rectifying circuit includes n rectifying diodes and n MOSFETs,
The n rectifying diodes and the MOSFETs are respectively arranged so that a diode bridge full-wave rectifying circuit is constituted by the n rectifying diodes and the parasitic diodes existing between the drains and sources of the n MOSFETs. It is composed of a circuit in which the two are located on the same side and bridge-connected. In the present invention, the n MOSFEs described above are used.
FE that gives a rectangular-wave drive signal of the same phase to the gate of T
A T control circuit is provided and n FETs are controlled by the FET control circuit.
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 means n M
By connecting n rectifying diodes in series to the drain-source circuit of the OSFET, n FEs are connected.
T / diode series circuit is configured to include the n FETs /
The diode series circuit is a circuit in which the respective MOSFETs and rectifying diodes are located on the same side and connected in parallel. In this case, in each FET / diode series circuit, the direction of the rectifying diode and the direction of the parasitic diode of the MOSFET should be the same.
Also, set the direction of the rectifying diode.

In the above structure, n MOSFETs are provided.
Is provided to form a switch circuit (chopper circuit) that turns on and off between the output terminals of the magnet generator. In the present invention, the switch circuit is turned on and off to interrupt the current flowing through the magneto coil of the magneto generator to induce a boosted voltage in the magneto coil,
A full-wave rectification circuit using a parasitic diode of a MOSFET as a part of a rectification element rectifies the boosted voltage so that a high voltage can be supplied to a load.

In the present invention, when the magneto generator has two output terminals 1a and 1b to generate a single-phase AC output,
The rectifier circuit has first and second rectifying diodes in which the cathodes are commonly connected (which means that they are connected to each other so as to form the same potential portion), as shown in the embodiment of FIG. 1, for example. It can be constituted by D1 and D2 and first and second MOSFETs F1 and F2 of N-channel type whose drains are respectively connected to the anodes of the first and second rectifying diodes and whose sources are commonly connected. In this case, the first and second rectifying diodes D1 and D2 and the parasitic diodes Df1 and Df2 existing between the drain sources of the first and second MOSFETs form a single-phase diode bridge full-wave rectifying circuit. , The single-phase AC output of the magneto-generator 1 is input between the 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 applying a rectangular-wave drive signal having the same phase is provided to the gates of the first and second MOSFETs, and the control circuit 3 simultaneously turns on and off the first and second MOSFETs forming the switch circuit. Let

As described above, the N-channel type MOSFET
In the case of using the above-mentioned rectifying circuit, the rectifying circuit also includes first and second rectifying diodes D1 and D2 having common anodes connected to each other and the first and second rectifying diodes as shown in the embodiment of FIG. It can also be constituted by N-channel type first and second MOSFETs F1 and F2 in which the source is connected to the cathode and the drain is commonly connected. In this case, the first and second rectifying diodes D1 and D2 and the parasitic diodes Df1 and Df2 existing between the drain sources of the first and second MOSFETs form a single-phase diode bridge full-wave rectifying circuit. , The single-phase AC output of the magneto-generator 1 is input between the connection points of the cathodes of the first and second rectifying diodes and the sources of the first and second MOSFETs. In this case as well, the FET control circuit 3 for applying the rectangular-wave drive signals of the same phase is provided to the gates of the first and second MOSFETs, and both MOSFETs are turned on / off simultaneously by the control circuit.

In the above example, the N-channel type MOSFET is used as the MOSFET, but the P-channel type MOSFET may be used as the MOSFET. P channel type M
When the OSFET is used, the rectifying circuit is, for example, as shown in
No. 0, the first and second rectifying diodes D1 and D2 with their anodes connected in common and the first and second rectifying diodes D1 and D2
And the second rectifying diode has a cathode connected to the drain and a common source connected to the P-channel first and second MOSFETs F1 and F2. Also in this case, the first and second rectifying diodes D1 and D2 and the first and second MOSFET F
A single-phase diode bridge full-wave rectification circuit is constituted by the parasitic diodes Df1 and Df2 existing between the respective drain sources of 1 and F2, and the cathodes of the first and second rectification diodes and the first and second MOSFETs. Input the output of the magneto generator 1 between the respective connection points with the drain of the. The point where the FET control circuit 3 is provided, which applies a rectangular-wave drive signal of the same phase to the gates of the first and second MOSFETs to turn both FETs on and off at the same time, is the same as above.

In the present invention, when the magneto generator has three output terminals 1a to 1c to generate a three-phase AC output,
In the rectifying circuit, for example, as shown in the embodiment of FIG. 5, first to third rectifying diodes D1 to D3 having cathodes commonly connected and drains to the anodes of the first to third rectifying diodes, respectively. 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 form a three-phase diode bridge full-wave rectifier circuit, and the anodes of the first to third rectifying diodes and the first to third MOSFETs The three-phase AC output obtained between the output terminals 1a to 1c of the magneto generator is input between the connection points 2u to 2w of the drain. Further, an FET control circuit 3 for providing a rectangular-wave drive signal of the same phase is provided to the gates of the first to third MOSFETs, and the FET control circuit controls the first to third MO transistors.
The SFET is turned on and off at the same time.

Even when a three-phase magneto generator is used, FIG.
Similarly to the embodiment shown in FIG.
To third rectifying diodes and first to third N-channel MOSFETs having sources connected to the anodes of the first to third rectifying diodes and commonly connected drains to form a rectifying circuit. be able to.

When a P-channel type MOSFET is used, the rectifying circuit has drains at the anodes of the first to third rectifying diodes and the anodes of the first to third rectifying diodes whose anodes are commonly connected. First to third MOSs connected to each other and commonly connected to sources
A three-phase diode bridge full-wave rectifier circuit is constituted by the FET, and the first to third rectifying diodes and the parasitic diodes of the first to third MOSFETs.

As described above, in the present invention, the MOS
A FET forms a switch circuit (chopper circuit) that turns on and off the output terminals of the magneto generator, and the switch circuit interrupts the current flowing through the magneto coil of the magneto generator to boost the output voltage of the magneto generator. . In the above configuration, when a rectifier circuit that rectifies a three-phase AC voltage is configured, three MOSFETs are provided and a switch circuit that short-circuits each of the three-phase magneto coils is configured. However, in the present invention, the DC voltage may be supplied to the load, and the output voltage of the magneto generator boosted by the chopper operation does not have to have a symmetrical waveform. The switching circuit may be configured to short-circuit only a part of the three-phase power generation coils among the three-phase power generation coils. In the example of FIG. 7, MOSFETs F1 and F2
A switch circuit for turning on / off between the output terminals 1a and 1b of the magneto generator 1 is configured, and 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 magneto-generator that outputs a multi-phase AC voltage has n output terminals, a MOSFET is formed so as to form a switch circuit that short-circuits at least two output terminals of the magneto-generator. Should be provided. Two MOSFETs are required to form a switch circuit that short-circuits the two magneto coils of the magneto generator. Therefore, when a N-channel type MOSFET is positioned on the negative DC output terminal side to form a rectifying circuit for step-up rectifying a multi-phase AC voltage, the configuration is generalized as follows.

That is, the rectifier circuit used when the magneto generator has n output terminals (n is an integer of 3 or more) is:
It is provided with m (m is an integer not less than 2 and not more than n) MOSFETs having sources commonly connected and drains connected to different output terminals of the magneto-generator and 2n−m rectifying diodes. The diode bridge full-wave rectification circuit for full-wave rectifying the multi-phase AC voltage is constructed by the parasitic diode existing between the drain and source of each MOSFET and the 2n-m rectification diodes so as to form a 2n-m rectification circuit. It is composed of a circuit in which a diode for power supply and m MOSFETs are bridge-connected. In this case, the FET control circuit is configured to apply a rectangular-wave drive signal having the same phase to the gates of the m MOSFETs to simultaneously turn on / off the m MOSFETs.

When a N-channel type MOSFET is positioned on the positive DC output terminal side to form a rectifying circuit for step-up rectifying a multi-phase AC voltage, the configuration is generalized as follows.
The rectifier circuit comprises m (m is an integer of 2 or more and n or less) MOSFETs having drains commonly connected and sources connected to different output terminals of the magneto generator and 2n−m rectifying diodes. 2n− and a parasitic diode existing between the drain and source of each of the m MOSFETs.
A diode bridge full-wave rectifier circuit for full-wave rectifying a multi-phase AC voltage with m rectifying diodes is formed so that 2n−m rectifying diodes and m MOSFEs are formed.
It is configured by a circuit in which T and T are bridge-connected. In this case as well, the FET control circuit applies a rectangular-wave drive signal of the same phase to the gates of the m MOSFETs to output the m MOSFs.
It is configured to turn ET 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 forming the full-wave rectifying circuit. However, in order to increase the current capacity, a parasitic diode is formed between the drain and source of each MOSFET. It does not prevent the parallel connection of diodes in the same direction.

[0038]

The function of the present invention will be described by taking the structure in the case where the magneto-generator generates a single-phase AC output as an example among the structures mentioned in the above section. In the power supply device configured as described above, as shown in FIG. 14 (A), the switch circuit for the chopper, which is composed of two MOSFETs F1 and F2 whose sources are connected in common and which are connected in series, is used for the magnet power generation. It is connected to both ends of the generator coil W1 of the machine.
When a drive signal is applied to the OSFETs F1 and F2 at the same time, a short circuit of the generator coil W1 is formed. When the same rectangular wave drive signal is applied to the two MOSFETs F1 and F2 to turn on and off both FETs at the same time, both FETs are turned on at the same time when the drive signal is applied to short-circuit the magneto coil W1 of the magnet generator. , Energy of (Li ² ) / 2 is stored in the power generation coil W1. When the rectangular-wave drive signal disappears, both FETs are cut off at the same time, so that the short-circuit current flowing through the generator coil W1 is cut off. At this time, a high voltage in the direction in which the short-circuit current that has been flowing until now continues to flow is induced in the generator coil W1, and this voltage is applied to the first and second diodes D1 and D1.
2 and the parasitic diodes Df1 and Df2 existing in the first and second MOSFETs are rectified by the full-wave rectification circuit and supplied to the load.

In the power supply device of the present invention, when a drive signal is applied to the first and second MOSFETs, current flows from the drain side to the source side of one FET,
In the other FET, current flows from the source side to the drain side. In the MOSFET to which a drive signal is applied (a predetermined voltage is applied between the source and gate), the drain current ID (or the reverse drain current IDR) flows at the same time as the voltage VSD is applied between the source and drain due to its characteristics. , If the source-drain voltage is within a certain range,
A drain current ID (or reverse drain current IDR) flows substantially 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 resistance, and the resistance value RDS between the source and drain in the ON state shows a substantially constant value in the region where VSD and ID are proportional. 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 given 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 (a) of FIG. Therefore, the threshold voltage required to make the FET conductive is substantially zero, and if a slight voltage is induced in the magneto coil of the magneto 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 generator coil, a short-circuit current will flow in the generator coil, and
A voltage can be induced in the magneto coil when the drive signal of T disappears and the short-circuit current is cut off.

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

In the above description, it is assumed that the magneto-generator produces a single-phase AC output, but the same applies to the case of producing a multi-phase AC output.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment in which a magneto generator produces a single-phase AC output. In FIG. 1, reference numeral 1 designates a magnet rotor mounted on a crankshaft of an internal combustion engine and a case of the engine. It is a magnet generator consisting of a stator fixed to. A magneto coil W1 is provided on the stator of the magneto generator 1, and an alternating voltage Ve is induced in the magneto coil W1 in synchronization with the rotation of the engine. In the present invention, the generator coil W1 has a small number of turns and a low impedance so that a large current can be taken out from the generator coil even when the engine is running at high speed.

Reference numeral 2 is a full-wave rectifier circuit for rectifying the AC voltage induced in the power generating coil W1, and this rectifier circuit has first and second diodes D1 and D2 whose cathodes are commonly connected.
And N-channel type first and second MOSFETs whose drains are respectively connected to the anodes of the first and second diodes D1 and D2 and whose sources are commonly connected.
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 the positive side DC output terminal 2a and the negative side DC output terminal 2b, respectively. The terminals are connected to the output terminals 4A and 4B of the power supply unit 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.
The output terminals 1a and 1b of the generator coil W1 of the generator 1 are connected to u and 2v, respectively. MOSFET F1
And F2 are N-channel type power MOSFE having parasitic diodes Df1 and Df2 between drain and source.
T is used, and the first and second parasitic diodes Df1 and Df2 and the first and second diodes D1 and D2, which are inherent in the first and second MOSFETs F1 and F2, respectively.
And constitute a single-phase diode bridge full-wave rectifier circuit.

In this example, MOSFETs F1 and F2
Thus, a switch circuit for a chopper that turns on and off between 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. One output terminal 3a is commonly connected to the gates of FETs F1 and F2, and the other output terminal 3b is FET.
A common connection point (minus side DC output terminal) 2b of the sources of F1 and F2 is connected. The FET control circuit 3 oscillates when a DC power supply voltage is applied, for example.
An oscillator for generating a rectangular wave signal as shown in (A), wherein the rectangular wave signal output from the control circuit 3 is applied as a drive signal VGS between the gate and source of the first and second MOSFETs. There is. In this embodiment, the MOS
In order to absorb the surge generated in the generator coil W1 when the FETs F1 and F2 are cut off, and the rectifier circuit 2
A capacitor Co is connected between the DC output terminals 2a and 2b of the rectifier circuit 2 in order to smooth the output voltage.

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 generator coil W1, and this rectangular wave signal is FET F
Both FETs are simultaneously driven by being applied as a drive signal VGS having the same phase between the gate and source of 1 and F2. FET
When a drive signal having a polarity in which the gate has a positive potential with respect to the source is applied between the gate and source of F1 and F2, both F
When ET F1 and F2 are in a state where they can be conducted, and even if a voltage with a polarity such that the drain has a positive potential with respect to the source is applied between the respective drains, a drain current flows in both FETs and the power generation coil W1 flows. 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 generator coil W1 is interrupted, and the short-circuit current that has been flowing until then continues to flow through the generator coil W1. The boosted voltage Vep (see FIG. 2B) is induced. Due to this voltage, a current Ie as shown in FIG. 2 (C) flows through the magneto coil W1,
Diodes D1 and D2 and parasitic diodes Df1 and Df2
A load current IL as shown in FIG. 2 (E) flows through the load RL through the full-wave rectification circuit constituted by Figure 2
(D) shows the waveform of the voltage VL across the load RL.

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

Therefore, two MOSFETs F1 and F2, to which a drive signal is applied, are applied to both ends of the power generation coil W1.
The circuit connected through the series circuit (switch circuit) of
It becomes equivalent to a circuit in which both ends of the generator coil are connected via a resistor, and the load line of the generator in the state where the drive signals are simultaneously applied to the two MOSFETs is a straight line passing through the origin as shown in (a) of FIG. Become. Therefore, the threshold voltage required to turn on the MOSFET becomes substantially zero, and if a slight voltage is induced in the magneto coil of the magneto generator, a short circuit current will flow in the magneto 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 generator coil, the MOSFETs F1 and F2 can be made conductive and a short-circuit current can flow in the generator coil. Therefore, the boosted voltage can be induced in the magneto coil when the drive signals of the MOSFETs F1 and F2 disappear and the short-circuit current is cut off.

It is now assumed that the magneto 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 of FIG. 3 and shows a waveform in the vicinity of the zero point of the output voltage of the generator (A part in FIG. 3).
FIG. 3B shows the waveform of the drive signal VGS given to the gate of the MOSFET. FIG. 4C shows the waveform of the current Ie flowing through the generator coil W1. According to the present invention, the current Ie flows even when the voltage Ve is almost zero. Therefore, a short-circuit current can be passed through the generator coil W1 from a state where the induced voltage is extremely low, and the load is driven by inducing a voltage by interrupting the short-circuit current even when the engine speed is low. You can

On the other hand, as shown in FIG. 14B, a conventional switch circuit for a chopper is formed by connecting a collector-emitter circuit of a transistor TRo to both ends of a magneto coil W1 through a diode Do. In the power supply device, as shown in FIG. 4D, the output voltage Ve of the generator is
Is below the threshold voltage Vt, the current Ie 'is generated in the generator coil.
Since it becomes impossible to flow the short-circuit current, the period in which the short-circuit current can flow becomes short, and the total amount of direct current that can be supplied to the load at extremely low speeds 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. When the conventional power supply device shown in FIG. 14B is used as the switch circuit for the chopper, the DC current can be supplied to the load only during the period T1 in FIG. 12, and the cranking in the period T1 is performed. The average number of rotations is N2. That is, in the case where the battery is not provided, the electric power cannot be supplied to the load unless the average value of the cranking rotation speed can be set to N2 by pulling the rope. On the other hand, according to the present invention, electric power can be supplied to the load during the entire period of To, T1 and T2 in FIG. 12, and the average value of the cranking speeds (To Since it is possible to reduce the average number of revolutions during the period from to T2) to N1 (<N2), it is possible to easily start the engine.

In the present invention, the MOSFET F
It is important to turn on and off 1 and F2 at the same time.
If the driving of one of the MOSFETs is delayed, the forward voltage drop of the parasitic diode of the MOSFET whose driving is delayed becomes the threshold voltage of the short-circuit circuit, so that the above effect cannot be obtained.

When a MOSFET, which is a voltage control element, is used as the switching element for the chopper that short-circuits and cuts off the power-generating coil as described above, it is possible to reduce the loss that occurs in the switching element when the power-generating coil is short-circuited. Therefore, heat generation from the power supply device can be reduced, and the heat dissipation plate attached to the switching element can be downsized.

FIG. 5 shows an embodiment in which the magneto generator produces a three-phase AC output. In this embodiment, the stator of the magneto generator 1 has three-phase magneto coils W1 to W3. However, these generator coils are star-connected. In this case as well, the number of turns of the magneto coils W1 to W3 is reduced to sufficiently lower the impedance of each coil. The rectifier circuit 2 includes first to third diodes D1 to D3 having common cathodes and first to third diodes D1 to D3.
First to third MOSs having drains connected to anodes 1 to D3 and sources commonly connected
FETs F1 to F3, and a common connection point of the cathodes of the first to third diodes D1 to D3 and the first
Or a circuit in which the common connection points of the sources of the third MOSFETs F1 to F3 are the positive side DC output terminal 2a and the negative side DC output terminal 2b, respectively. The connection points 2u, 2v and 2w of 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
The output terminals 1a, 1b and 1c on the side opposite to the neutral point of the magneto coils W1, W2 and W3 are connected to w. In this example, the MOSFETs F1 to F3 constitute a switch circuit for a chopper that turns on and off the output terminals 1a, 1b, 1c of the magneto generator.

Between the output terminals 2a and 2b of the rectifier circuit 2,
An FET control circuit 3 for applying a rectangular-wave drive signal of the same phase to the gates of the first to third MOSFETs F1 to F3 to turn on / off the first to third MOSFETs at the same time.
The gates and sources of the MOSFETs F1 to F3 are commonly connected to the output terminals 3a and 3b of the control circuit. As each MOSFET, an N-channel type having a parasitic diode between the drain and the source is used as in the embodiment of FIG. 1, and the first to third diodes D1 to D3 and the first to third MOSFETs are used.
3 with the parasitic diodes Df1 to Df3 of F1 to F3
A phase diode bridge full-wave rectifier circuit is configured.
The other points are similar to those of the embodiment shown in FIG.

In the embodiment shown in FIG. 5, the first through third
The MOSFETs F1 to F3 are simultaneously driven by the rectangular-wave drive signal VGS as shown in FIG. As a result, the short-circuiting and interruption of the magneto coils W1 to W3 are repeated, and when the MOSFETs F1 to F3 are interrupted, the boosted voltage is induced in the magneto coils W1 to W3. This voltage is supplied to the load through a full-wave rectifying circuit composed of rectifying diodes D1 to D3 and parasitic diodes Df1 to Df3. FIG. 6B shows the voltage VL applied to the load RL.
6C, and FIG. 6C shows the 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, but in order to prevent the output voltage from becoming too high at the time of high speed rotation of the engine, the output voltage becomes too high. So as to be less than or equal to the set value, the duty ratio (= the signal width of the drive signal / the generation period of the drive signal) of the drive signal output from the FET control circuit 3 and / or the frequency of the drive signal are controlled according to the output voltage. It may be controlled. Further, when the output voltage becomes excessively high even when the drive signal is zero when the engine is rotating at high speed, a voltage regulator that suppresses the output voltage rise by short-circuiting the output of the magneto generator 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 installed, the control circuit 3 is driven by the battery. You may Further, when the battery is not mounted, the FET control circuit 3 may be driven by using a simple battery such as a dry battery.

In the above embodiment, the three-phase AC voltage is boosted,
Three MOSFEs are used to form a rectifying circuit for rectifying.
The switch circuit is configured so as to turn on / off each of the three output terminals of the magnet generator by providing T, but the switch circuit is configured to turn on / off only between some output terminals of the magnet generator. You can also do it. FIG. 7 shows an embodiment thereof, and in this example, the first and second MO
SFETs F1 and F2 and four rectifying diodes D
The rectifier circuit 2 is composed of 1 to D3 and D3 '. The configuration of this rectifier circuit is MO in the embodiment of FIG.
This corresponds to the SFET F3 replaced by the diode D3 '.

In the case of the configuration shown in FIG. 7, the MOSF
ET F1 and F2 are turned on and off to interrupt only the current flowing through some of the magneto coils W1 and W2 of the magnet generator, so the output voltage of the magnet generator has an asymmetric waveform. Since it is rectified and smoothed by the capacitor Co and supplied to the load RL, it does not hinder the driving of the load.

In the above embodiment, the sources of the MOSFETs are connected in common, the drains are connected to the anodes of the corresponding rectifying diodes, and the MOSFETs are positioned on the negative DC output terminal side of the rectifying circuit to form the rectifying circuit. But
The MOSFET may be connected so that the direction of its parasitic diode is the same as the direction of the rectifying diode, and the connection is not limited to that 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 the diodes D1 and D2 whose anodes are commonly connected, The 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 give 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, but when a rectifier circuit that rectifies a three-phase AC output is formed, the MOSFET is connected to the positive DC output terminal side. It can be positioned. That is,
First to third MOSFETs F1 to F3 and first to third rectifying diodes D1 to D3 are provided, and
The drains of the first to third MOSFETs are commonly connected to the positive DC output terminal of the rectifier circuit, and the sources of these first to third MOSFETs F1 to F3 are commonly connected to the negative DC output terminal of the anode. It is also possible to adopt a configuration in which the cathodes of the first to third rectifying diodes D1 to D3 are respectively connected.

Further, as shown in FIG. 7, when a switch circuit for turning on / off only a part of output terminals of the magnet generator is constituted by MOSFETs smaller in number than the output terminals of the multi-phase magnet generator, Can be provided on the positive DC output terminal side.

Generally, in order to construct a rectifying circuit for rectifying and boosting the output of a magnet generator which has n (n is an integer of 3 or more) output terminals and outputs a multi-phase AC voltage, the magnet generator is used. The switch circuit may be configured to short-circuit at least two output terminals of the machine. In order to configure a switch circuit that short-circuits between two magneto coils of a magneto generator,
Two MOSFETs are needed. Therefore, in a rectifier circuit that positions an N-channel MOSFET on the negative DC output terminal side to boost and rectify a multi-phase AC voltage, the sources are commonly connected and the drains are connected to different output terminals of the magneto generator. MOSFETs (m is an integer from 2 to n)
And 2n−m rectifying diodes, and full-wave rectify the multi-phase AC voltage by the parasitic diodes existing between the drain and source of the m MOSFETs and the 2n−m rectifying diodes. A diode bridge full-wave rectifier circuit can be configured 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
The gates of the OSFETs are configured to be supplied with in-phase rectangular wave drive signals to simultaneously turn on / off the m MOSFETs.

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

In the above embodiment, each MOSFET is in the off state when the potential of the gate with respect to the source is 0 volt, and is in the on state when a drive signal for making the gate potential positive with respect to the source is given. P channel that is in the ON state when the gate potential is 0 volt and is in the OFF state when a drive signal that makes the gate potential a positive potential with respect to the source is given. Shape 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 the first and second P-channel type MOSFETs F1 and F2 are commonly connected and the first and second MOSFETs F1 and F2 are connected together. The anodes of the first and second rectifying diodes D1 and D2 are commonly connected, and MO
The drains of SFETs F1 and F2 are connected to the cathodes of diodes D1 and D2, respectively. MOSFET
F1 and F2 parasitic diode and rectifying diode D1
And D2 form 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 of the OSFETs F1 and F2 (the positive side output terminal of the rectifier circuit) is required.

Also in this case, the drains are connected to the anodes of the first to third rectifying diodes D1 to D3 and the anodes of which the anodes are commonly connected, and the sources are commonly connected. P-channel type first to third MOSFETs F1 to F3
With, a rectifier circuit for boosting and rectifying the three-phase AC output can be configured.

Even when a rectifying circuit for rectifying a multi-phase AC output voltage is constructed by using a P-channel type MOSFET,
Similar to the case of using the N-channel type MOSFET, the number of MOSFEs which is smaller than the number of output terminals of the magnet generator is set so that only some output terminals of the magnet generator are turned on and off.
A switch circuit can be formed by T.

In general, a rectifier circuit for boosting and rectifying 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 outputting a DC voltage is , N-sources connected in common and drains connected to different output terminals of the magneto-generator (m is an integer of 2 or more and n or less), and 2n−
With m rectifying diodes, m MOSFE
In order to form a diode bridge full-wave rectification circuit for full-wave rectifying the multi-phase AC output voltage by the parasitic diode existing between the drain and source of T and 2n−m rectification diodes, m MOSFETs and 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 invention disclosed in the present specification are as follows.

(1) A magnet generator that is 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 a plurality of output terminals, wherein the rectifier circuit includes n rectifying diodes and n MOSFETs, Rectifier diode and n MOSFETs
A circuit in which the n number of rectifying diodes and MOSFETs are positioned on the same side and bridge-connected so that a diode bridge full-wave rectifying circuit is constituted by a parasitic diode existing between each drain source of T. And a switch circuit for turning on and off between the n output terminals of the magneto-generator is constituted by the n MOSFETs, and a rectangular-wave drive signal of the same phase is applied 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 / off T at the same time.

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

(3) In the internal-combustion-engine power supply device for full-wave rectifying the single-phase AC output voltage of the magnet generator driven by the internal combustion engine to output the DC voltage, the drains are commonly connected and the source is the magnet generator. Switch circuit composed of first and second MOSFETs respectively connected to different output terminals of the machine, parasitic diodes existing between the drain and source of the first and second MOSFETs, and first and second rectification A diode bridge full-wave rectification circuit configured by a diode to perform full-wave rectification of an AC voltage obtained between output terminals of the magnet generator, and rectangular-wave drive of the same phase for 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 the internal-combustion-engine power supply device for full-wave rectifying the single-phase AC output voltage of the magnet generator driven by the internal combustion engine to output the DC voltage, the sources are commonly connected and the drain is the magnet generator. P-channel type first and second MOSFs respectively connected to different output terminals of the machine
A switch circuit including an ET and the first and second MOs
A diode-bridge full-wave rectification circuit for full-wave rectifying an AC voltage obtained between the output terminals of the magneto generator, which is composed of a parasitic diode existing between the drain and source of each SFET and first and second rectification diodes. When,
A power supply device for an internal combustion engine, comprising: a FET control circuit that applies a rectangular-wave drive signal of the same phase to the gates of the first and second MOSFETs to turn both MOSFETs on and off at the same time.

(5) In a power supply device for an internal combustion engine which outputs a DC voltage by full-wave rectifying the three-phase AC output voltage of a magnet generator driven by the internal combustion engine, the sources are commonly connected and the drain is the magnet power generator. N-channel type first to third MOSs respectively connected to different output terminals of the machine
Between the output terminal of the magneto-generator, the switch circuit including an FET, the parasitic diode existing between the drain and source of each of the first to third MOSFETs, and the first to third rectifying diodes. A diode bridge full-wave rectification circuit for full-wave rectifying the obtained three-phase AC voltage, and a rectangular-wave drive signal of the same phase are given to the gates of the first to third MOSFETs to drive the first to third MOSFETs. A power supply device for an internal combustion engine, comprising: a FET control circuit for simultaneously turning on and off.

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

(7) A polyphase obtained between the n output terminals of a magneto generator that is 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, m sources of the N-channel type (m is 2 or more and n are connected to each other) have sources commonly connected and drains connected to different output terminals of the magneto-generator. A switch circuit composed of MOSFETs (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 configured by n-m rectifying diodes to perform full-wave rectification of the multiphase AC output voltage of the magneto-generator, and a rectangular-wave-shaped rectangular wave having the same phase at the gates of the m MOSFETs. Applying a drive signal, the m M
A power supply device for an internal combustion engine, comprising: a FET control circuit that simultaneously turns on and off the OSFET.

(8) A polyphase obtained between the n output terminals of a magnet generator that is driven by an internal combustion engine and generates 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, m drains of m-channels (m is 2 or more and n are connected to each other) are commonly connected to drains and connected to different output terminals of the magneto-generator. A switch circuit composed of MOSFETs (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 configured by n-m rectifying diodes to perform full-wave rectification of the multiphase AC output voltage of the magneto-generator, and a rectangular-wave-shaped rectangular wave having the same phase at the gates of the m MOSFETs. Applying a drive signal, the m M
A power supply device for an internal combustion engine, comprising: a FET control circuit that simultaneously turns on and off the OSFET.

(9) A polyphase obtained between the n output terminals of a magneto generator that is 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 that rectifies an AC voltage and outputs a DC voltage, m sources of the P-channel type (m is 2 or more and n are commonly connected to each other and have drains connected to different output terminals of the magneto-generator). A switch circuit composed of MOSFETs (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 configured by n-m rectifying diodes to perform full-wave rectification of the multiphase AC output voltage of the magneto-generator, and a rectangular-wave-shaped rectangular wave having the same phase at the gates of the m MOSFETs. Applying a drive signal, the m M
A power supply device for an internal combustion engine, comprising: a FET control circuit that simultaneously turns on and off the OSFET.

[0082]

As described above, according to the present invention, at least two outputs of the magneto-generator are provided by a plurality of MOSFETs in which the relationship between the applied voltage and the energized current is the same as when the voltage is applied to the resistor. A bridge full-wave rectifier circuit is constituted by a parasitic diode existing between the drain and source of the MOSFET and another rectifying diode, and a plurality of MOSFETs.
Since the plurality of MOSFETs are simultaneously turned on and off by turning on and off between the output terminals of the magneto-generator to boost the output voltage of the magneto-generator, the short-circuit current is generated in the generator. The threshold voltage of the applied voltage required to flow is substantially zero, and from the state where the output voltage of the generator is extremely low, it is possible to flow a short-circuit current through the MOSFET to the generator coil to perform boosting operation,
There is an advantage that power can be supplied to the load even when the engine is extremely low speed.

Further, according to the present invention, an MO having a parasitic diode as a switching element for short-circuiting the magneto coil
Since the full-wave rectifier circuit is configured by 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 switching element for short circuit, the loss generated in the switching element when the power generating coil is short-circuited can be made small, and the loss is generated in the switching element. There is an advantage that heat generation can be suppressed and the heat sink can be downsized.

[Brief description of drawings]

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

FIG. 2 is a waveform diagram showing signal waveforms of respective parts in FIG.

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

FIG. 4 is a waveform diagram for explaining a difference in operation when an FET is used as a switching element that short-circuits a power generation coil and when a bipolar transistor is used.

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

FIG. 6 is a signal waveform diagram of each part of 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.

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 diagram 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 the output voltage-output current characteristics of the magnet generator together with the load line.

FIG. 14 (A) is a circuit diagram showing a short circuit of a magneto coil in an example of the present invention. (B) is a circuit diagram showing a short circuit of a power generating coil in a conventional power supply device.

FIG. 15 is a diagram showing an example of output voltage versus output current characteristics required for a magnet generator attached to an internal combustion engine equipped with a battery.

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

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 vs. collector current characteristic of a transistor.

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

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

21 is a diagram showing a reverse drain current-source-drain voltage characteristic of the same MOSFET as FIG. 20. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magneto-generator 1a-1c Output terminal W1-W3 Generator coil 2 Rectifier circuit D1-D3 1st thru | or 3rd rectifying diode F1-F3 1st thru | or 3rd MOSFET Df1-Df3 1st thru | or 3rd parasitic diode 3 FET control circuit RL load

Claims (7)

[Claims] 1. n (n is 2) driven by an internal combustion engine.
A magnet generator that generates a single-phase or multi-phase AC voltage between the output terminals (the above integers), 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 transistors.
The n rectifying diodes are provided so that a diode bridge full-wave rectifying circuit is constituted by the n rectifying diodes and the parasitic diodes existing between the drain sources of the n MOSFETs. And M
An FET control circuit which is composed of a circuit in which OSFETs and bridges are connected to each other on the same side, and a rectangular-wave drive signal of the same phase is applied to the gates of the n MOSFETs to simultaneously turn on / 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. Commonly connected first and second rectifying diodes, and N-channel first and second drains connected to the anodes of the first and second rectifying diodes, and sources commonly connected
And a second rectifying diode and a parasitic diode existing between the drain and source of each of the first and second MOSFETs to form a single-phase diode bridge full-wave rectifying circuit. The single-phase AC output of the magneto-generator is input between the connection points of the anodes of the first and second rectifying diodes and the drains of the first and second MOSFETs, respectively. A power supply device for an internal combustion engine, comprising: a FET control circuit that applies a rectangular-wave drive signal of the same phase to the gate of the second MOSFET to simultaneously turn on and off both MOSFETs. 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 full-wave rectifying a single-phase AC output of the magnet generator, wherein the rectifier circuit has an anode. First and second rectifying diodes connected in common, and N-channel first and second rectifying diodes whose sources are connected to the cathodes of the first and second rectifying diodes and whose drains are connected in common.
And a second rectifying diode and a parasitic diode existing between the drain and source of each of the first and second MOSFETs to form a single-phase diode bridge full-wave rectifying circuit. The single-phase AC output of the magneto-generator is input between the connection points of the cathodes of the first and second rectifying diodes and the sources of the first and second MOSFETs, respectively. A power supply device for an internal combustion engine, comprising: a FET control circuit that applies a rectangular-wave drive signal of the same phase to the gate of the second MOSFET to simultaneously turn on and off both MOSFETs. 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 full-wave rectifying a single-phase AC output of the magnet generator, wherein the rectifier circuit has an anode. Commonly connected first and second rectifying diodes, and P-channel first and second drains connected to the cathodes of the first and second rectifying diodes, and sources commonly connected
And a second rectifying diode and a parasitic diode existing between the drain and source of each of the first and second MOSFETs to form a single-phase diode bridge full-wave rectifying circuit. The single-phase AC output of the magneto-generator is input between the connection points of the cathodes of the first and second rectifying diodes and the drains of the first and second MOSFETs, respectively. And a FET control circuit that applies a rectangular-wave drive signal of the same phase to the gate of the second MOSFET to turn both FETs on and off 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. First to third rectifying diodes connected in common and first to third N-channel type rectifying diodes whose drains are respectively connected to anodes of the first to third rectifying diodes and whose sources are commonly connected And a first-third rectifying diode and a parasitic diode of the first-third MOSFET to form a three-phase diode bridge full-wave rectifier circuit. Rectifier diode anode and first to third MOS
The three-phase AC output of the magneto-generator is input between the respective connection points with the drain of the FET, and a rectangular-wave drive signal of the same phase is given to the gates of the first to third MOSFETs to supply the first-third MOSFET. To the third MOS
A power supply device for an internal combustion engine, comprising an FET control circuit for simultaneously turning on and off the FETs. 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 the three-phase AC output of the magnet generator, wherein the rectifier circuit has an anode. First to third rectifying diodes connected in common and first to third P-channel type rectifying diodes whose drains are connected to anodes of the first to third rectifying diodes and whose sources are connected in common A first-third rectifying diode and a parasitic diode of the first-third MOSFET to form a three-phase diode-bridge full-wave rectifier circuit. Rectifier diode cathode and first to third MOSFETs
The three-phase AC output of the magneto-generator is input between respective connection points with the drain of T, and the first-third MOSFET gates are supplied with in-phase rectangular-wave drive signals to provide the first-third MOSFET drive signals. To the third MOS
A power supply device for an internal combustion engine, comprising an FET control circuit for simultaneously turning on and off the FETs. 7. An n number (n is 3) driven by an internal combustion engine.
An internal combustion engine including a magneto generator that generates a polyphase AC voltage between output terminals of the above integers) and a rectifier circuit that rectifies the polyphase AC voltage obtained between n output terminals of the magneto generator. In the power supply device for m, the rectifier circuit has m sources (m is 2), the sources of which are commonly connected and the drains of which are connected to different output terminals of the magneto-generator.
(N is an integer equal to or less than n) and 2n−m rectifying diodes, and the parasitic diodes existing between the drain and source of the m MOSFETs and the 2n−m rectifying diodes are used. A diode bridge full-wave rectifying circuit for full-wave rectifying the multi-phase AC voltage. The circuit is configured by bridge-connecting the 2n−m rectifying diodes and m MOSFETs, and the m MOSFETs. An internal combustion engine power supply device is provided with an FET control circuit that applies a rectangular-wave drive signal of the same phase to the gates of the above-mentioned FETs to simultaneously turn on / off the m MOSFETs.