JPH04251599A - Power supply for vehicle - Google Patents

Abstract

PURPOSE:To facilitate driving of electrical load of vehicle, starting of engine and suppression of engine torque pulsation through a single rotating machine and to provide a power supply for vehicle in which such elements as transistors can be reduced in size and heat production and fluctuation of power supply voltage for the electric load of vehicle can be reduced. CONSTITUTION:A complex bridge 2 for feeding/receiving power between a single three-phase AC rotating machine for vehicle and a high voltage capacitor 4 is constituted of a diode 21 and a transistor 22. The rotating machine 1 and a low voltage storage means (a battery 2 or a poor capacitor) of vehicle rated voltage are connected through an SCR half-bridge and the complex bridge starts the engine and absorbs the exciting torque.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle power supply device, and more particularly to a vehicle power supply device useful for improving startability and quietness of an internal combustion engine.

0002

2. Description of the Related Art Conventionally, there have been proposals to use a vehicle generator as a starter motor for starting an internal combustion engine. This device has a composite bridge that connects the three-phase winding wound around the armature and the battery, and this composite bridge constitutes a three-phase full-wave rectifier and outputs from the three-phase winding. A plurality of diodes charge the battery by full-wave rectifying the three-phase AC voltage, and both ends of each diode are short-circuited at a predetermined timing to supply the three-phase AC current for starting from the battery to the three-phase winding. It consists of a plurality of transistors that supply

[0003] Furthermore, a proposal has been made to reduce the torque pulsation caused by the explosion of the internal combustion engine by causing a three-phase alternating current rotary machine for a vehicle driven by an internal combustion engine to generate electricity and operate electrically in synchronization with the explosion of the internal combustion engine. It is being

0004

[Problems to be Solved by the Invention] However, in the above-mentioned plan of using the conventional vehicle generator as a starting motor, the starting current is much larger than the rated generation current.
A troublesome problem arises in that large power transistors having a large allowable current must be used as transistors for the inverter of the composite bridge, and sufficient consideration must be given to cooling them. .

On the other hand, in a scheme in which a three-phase alternating current rotating machine for a vehicle driven by an internal combustion engine generates electricity and operates electrically in synchronization with the explosion of the internal combustion engine, the battery voltage fluctuates due to the frequent repetition of electrical generation and electrical operation. Also, problems arise in that power loss due to wiring resistance cannot be ignored. Furthermore, since a large current flows in both power generation and electric power generation, there is a drawback that the power loss of the transistor is large. Furthermore, there are concerns that the repeated rapid charging and discharging of the battery due to such frequent repetition of the generator-motor operation will increase the internal power loss and heat generation of the battery, and shorten the service life of the battery.

The present invention was developed in view of these problems, and aims to reduce the size of the transistor of the composite bridge, reduce power loss during starting and generator motor operation, and, despite these functional enhancements, The object of the present invention is to provide a power supply device for a vehicle that is free from concerns about shortening of battery service life.

[0007]

[Means for Solving the Problems] The vehicle power supply device of the present invention includes a vehicle three-phase AC rotating machine driven by an internal combustion engine, and each of the three-phase armature windings of the vehicle three-phase AC rotating machine. a composite bridge comprising diodes connected to the output end in a three-phase full-wave rectifier bridge format and transistors individually connected in parallel to each of the diodes; connected to the DC output end of the composite bridge; A high-voltage capacitor that transfers power to and from the vehicle three-phase AC rotating machine via the composite bridge, and each input terminal connected to each output terminal of the three-phase armature winding, and A half bridge rectifies the output three-phase AC voltage, one end is connected to the output end of the half bridge, the other end is connected to one end of the DC output end of the composite bridge, and the vehicle rated voltage load is connected to the half bridge. The present invention is characterized in that it includes a low-voltage power storage means for driving, and a control means for controlling the generated voltage of the three-phase alternating current rotating machine for a vehicle.

[0008] As the half bridge, various three-terminal switching elements such as an SCR and a transistor can be used.

[0009]

[Operation] In the low voltage storage means charging mode, the half bridge is operated to cut off the transistors of the composite bridge, and the control means reduces the current flowing to the field coil to reduce the generated voltage. This charges the low voltage storage means. The high-voltage capacitor is charged when the voltage is lower than the low-voltage storage means, and is not charged when the voltage is lower than the low-voltage storage means.

In the high-voltage capacitor charging mode used to absorb engine torque pulsations, the transistors of the half-bridge and composite bridge are cut off, and the control means increases the current flowing to the field coil to increase the generated voltage. This charges the high voltage capacitor and separates the low voltage storage means from the power generation side. In the high-voltage capacitor discharge mode used for engine starting and engine torque pulsation absorption,
The half bridge is cut off and the transistors of the composite bridge are made alternately conductive, and the control means appropriately controls the current flowing to the field coil. As a result, the rotating machine is driven as an electric motor by the discharged power from the high-voltage capacitor.

[0011]

Therefore, according to the present invention, high-voltage power is transferred between a high-voltage capacitor and a vehicle three-phase AC rotating machine through a composite bridge, and a low-voltage storage device that drives a vehicle rated voltage load by a half-bridge is provided. Since a configuration is adopted in which the means is charged, the starting current and the generator motor current for absorbing torque pulsation can be significantly reduced.
Rotating machines, composite bridge transistors and diodes,
The resistance loss, heat generation, size, and cost of high voltage wiring can be significantly reduced. For example, if the vehicle rated voltage is 14V
If the maximum voltage of the high-voltage capacitor is 280V, the current can be reduced to 1/20th, and the resistance loss can thereby be reduced to 1/400th.

Further, according to the present invention, since the high voltage capacitor and the above-mentioned high voltage rated composite bridge are used for the starting operation and for suppressing torque pulsation of the internal combustion engine, the voltage of the low voltage storage means that drives the vehicle rated voltage load is reduced. Fluctuations can be prevented, and furthermore, even when a battery is used as the low-voltage storage means, shortening of its service life can be prevented.

Furthermore, according to the present invention, the device configuration can be significantly simplified compared to the case where two systems of high voltage power supply and low voltage power supply are provided completely independently.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the vehicle power supply device of the present invention. This vehicle power supply device has a three-phase AC rotating machine 1 connected to a rotating shaft of an engine (not shown), and this three-phase rotating machine 1 has an excitation winding 11 wound around a rotor. , an armature winding 12 wound around a stator, and a damper conductor circuit 13 provided on a rotor. Damper conductor circuit 13
has the same structure and function as the squirrel cage conductor circuit of a so-called squirrel cage induction motor.

A composite bridge 2 and a half bridge 3 are connected to each output end of the star-connected armature winding 12. The composite bridge 2 consists of six diodes 21 connected as a three-phase full-wave rectifier bridge, and six MOS transistors 22 individually connected in parallel with each diode 21. , three SCRs 31 each having an anode connected to each output end of the armature winding 12 and a cathode connected in common.

The high output end of the composite bridge 2 is directly connected to one end of a high voltage capacitor 4, and the other end of the high voltage capacitor 4 is grounded. The common cathode end of the half bridge 3 is connected to the positive electrode of a battery 6 (low voltage storage means in the present invention) having a constant voltage of 14.4 V, and the other end of the battery 6 is grounded. The one end of the high voltage capacitor 4 is connected via a switch 5 to the high end of a high voltage load 9 consisting of an ice melting device, and the positive electrode of the battery 6 is connected to one end of a vehicle electric load 8. The lower end of the high voltage load 9 and the other end of the vehicle electrical load 8 are grounded.

Furthermore, the positive electrode of the battery 6 and the high end of the high voltage capacitor 4 are connected by a converter 7. This converter 7 is a bidirectional DC-DC converter, and has a reactor 71 connected to the positive electrode of the battery 6 at one end.
, a MOS transistor 72 connecting the other end of the reactor 71 and the high end of the high voltage capacitor 4, and the reactor 7.
Further, backflow prevention diodes 74 and 75 are individually connected in parallel to each transistor 72 and 73, respectively.

Excitation winding 13, MOS transistor 22,
72, 73, and SCR 31 are energized and controlled by control means 100. As shown in FIG. 2, this control means 100 includes a microcomputer 101 that calculates various signals received, and drive circuits 102, 103, and 1 that generate necessary switching signals based on the signals output from the microcomputer 101.
Consisting of 04 and 105. Such a microcomputer control circuit itself is well known, and since it departs from the main part of the present invention, a detailed circuit explanation will be omitted. However, the three-phase AC rotating machine for vehicles is equipped with a rotor position sensor that detects the angular position of the rotor (not shown), and the rotor position signal is transmitted to the control means 10.
It is input to 0.

The operation of this vehicle power supply device will be explained below. (Low-voltage power storage means charging mode) In the low-voltage power storage means charging mode, the control means 100 performs necessary charging based on the rotor position signal (or may be based on the phase of the three-phase AC voltage input to the composite bridge 2). Switching control is performed to alternately turn on each SCR 31 of the half bridge 3 in synchronization with the phase of the generated three-phase AC voltage, while the transistor 22 of the composite bridge 2 is turned off. Further, the control means 100 controls the excitation current by the duty ratio control switching operation of the drive circuit 102, and sets the generated voltage of the rotating machine 1 to a value suitable for the battery 6. Thereby, the battery 6 is charged, and the battery 6 drives the vehicle electric load 8. (High Voltage Load Drive Mode) In the high voltage load drive mode, the control means 100 shuts off each SCR 31 of the half bridge 3 and the transistor 22 of the composite bridge 2. Further, the control means 100 controls the excitation current by the duty ratio control switching operation of the drive circuit 102, and changes the generated voltage of the rotating machine 1 to the high voltage load 9.
The voltage is increased to an appropriate value (300V).

The three-phase AC high voltage generated by the armature 12 is three-phase full-wave rectified by each diode of the composite bridge 2, and then supplied to the high voltage load 9. At this time, high voltage capacitor 4 is also
Charged to 00V. The high voltage load mode is started when the control means 100 detects that the switch 45 is turned on, and ends when the control means 100 detects that the switch 5 is turned off. (Engine starting mode) In the engine starting mode, the control means 100 controls the composite bridge 2
The switching control necessary for the transistor 22 is performed, and a three-phase AC voltage is applied to the armature winding 12. As a result, an induced current flows through the damper conductor circuit 13 as a squirrel cage conductor circuit due to the rotating magnetic field generated in the stator, thereby generating a starting torque in the rotor and starting the engine. Thereafter, the switching of the transistor 22 is controlled based on the rotor position signal, and current is applied to the excitation winding to accelerate the motor as a commutatorless DC motor.

At this time, the control means 100 controls the drive circuit 1
The duty ratio control switching operation of 02 increases the excitation current, strengthens the magnetic poles of the rotor, and increases the starting torque. The important thing is to connect the starting power to high voltage capacitor 4.
Since the starting current is reduced and the resistance loss is greatly reduced, the transistor 22 of the composite bridge 2 can also be made smaller, and the loss due to the internal resistance of the high-voltage capacitor 4 is also small. (Engine Torque Pulsation Suppression Mode) The engine torque pulsation suppression mode suppresses torque fluctuations caused by explosions in the reciprocating internal combustion engine. That is, when the engine torque is low, a three-phase pulse voltage of a predetermined phase is applied to the armature winding 12 by switching control of the transistor 22 to drive the rotor and assist the torque generated by the engine. Therefore, in this case, the high voltage capacitor 4 is discharged to the three-phase AC rotating machine 1 for the vehicle.

Conversely, when the engine torque is high, the transistor 22 is turned off and the three-phase AC voltage generated by the armature winding 12 is rectified by the diode 21 into a three-phase full wave to charge the high voltage capacitor 4. . Figure 3(a) shows engine rotational fluctuations, Figure 3(b) shows the torque generated to cancel this rotational fluctuation, and Figure 4(c) shows the torque during electric operation in Figure 3(b). This figure shows the change in pulse width. That is, the transistor 22 is given a PWM (pulse width modulation) signal as shown in FIG. 4(d) based on the rotor position signal, and switches between an electric operation and a power generation operation. In this way, vibrations due to engine torque fluctuations can be reduced. Note that in this mode, the control means 10
0 can also control the torque by controlling the duty ratio of the pulse current applied to the excitation winding 11. In this way, engine torque pulsation can be suppressed.

What is important is that the vibration damping power is temporarily stored by an independent high voltage capacitor 4, so the battery 6
It is possible to reduce the burden on the power supply and its power supply voltage fluctuations. Further, since the capacitor can be rated at a high voltage of, for example, 300V, various resistance power losses can be reduced. Furthermore, it also helps to extend the service life of the battery 6. Next, the operation of the converter 7 will be explained.

This converter 7 is used to mutually exchange electric power between the battery 6 and the high voltage capacitor 4, and the voltage of the battery 6 and the voltage of the high voltage capacitor 4 are monitored by the control means. Based on this, switching of the transistors 72 and 73 is controlled as appropriate. That is, in order to transmit power from the battery 6 to the high-voltage capacitor 4, the transistor 73 is made conductive for a short time to accumulate magnetic energy in the reactor 71, and then the transistor 73 is cut off and the high voltage generated in the reactor 71 is transferred to the diode. 74
The voltage is applied to the high voltage capacitor 4 through. Repeat this at high speed. To transmit power from the high-voltage capacitor 4 to the battery 6, the transistor 73 is cut off, the transistor 72 is turned on and off at high speed, and the magnetic energy accumulated in the reactor 71 by the current from the high-voltage capacitor 4 is converted into a current after the transistor 72 is cut off. Supplied to battery 6.

FIG. 4 shows an example of the vehicle three-phase AC rotating machine 1 used in the above embodiment. A clutch disc 202 is attached to the drive shaft, that is, the crankshaft 201 of the internal combustion engine 200.
are directly connected. A rotor 19 of a three-phase AC rotating machine 1 for a vehicle is fitted into the clutch disc 202 so as to be rotatable and displaceable in the axial direction. They are facing each other with a distance between them. A ring-shaped recess is provided on the left end surface of the rotor 19 in the drawing, and a yoke 17 around which the excitation winding 11 is wound is accommodated in this recess. Unlike the rotor 19, the yoke 17 is arranged so that it cannot rotate.
The right end portion 17a of 7 is thin. Also, rotor 1
A damper conductor circuit (not shown) is provided on the outer circumferential surface of rotor 19, and a stator 18 on which armature winding 12 is wound is provided at a predetermined distance from the outer circumferential surface of rotor 19. There is.

At the time of starting, a three-phase alternating current whose frequency gradually increases is applied to the armature winding 12, whereby the rotor 19 is rotated by the action of the squirrel cage induction motor by the damper conductor circuit. When the rotation exceeds a certain level, the armature current is optimally controlled based on the rotor position signal, and then the excitation winding 11 is energized to operate as a commutatorless motor. That is, the right end 17a of the yoke 17 is magnetically saturated by the excitation current, and the soft magnetic rotor 1 is caused by leakage magnetic flux.
9 is attracted to a soft magnetic clutch disk 202, the rotor 19 is directly connected to a crankshaft 201 of an internal combustion engine 200, and the engine 200 is started.

In this embodiment, the operation of the engine torque pulsation suppression mode described above is carried out during idling when vibrations are noticeable.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of a vehicle power supply device of the present invention.

[Figure 2] Block diagram of the control means in Figure 1

[Figure 3] Torque fluctuation diagram

[Figure 4] Control voltage waveform diagram

[Figure 5] Cross-sectional view of the three-phase AC rotating machine for vehicles adopted in this example

[Explanation of symbols]

1 Three-phase AC rotating machine for vehicles 2 Composite bridge 3 Half bridge 4 High voltage capacitor 6 Battery 7 Converter 8 Vehicle electrical load 9 High voltage load 100 Control means

Claims (1)

[Claims] Claim 1: A three-phase AC rotating machine for a vehicle driven by an internal combustion engine, and a three-phase full-wave rectifying bridge connected to each output end of a three-phase armature winding of the three-phase AC rotating machine for a vehicle. a composite bridge consisting of a diode and a transistor individually connected in parallel to each diode; a high-voltage capacitor that transfers power to and from the machine, and a half bridge whose input terminals are connected to each output terminal of the three-phase armature winding, and which rectifies the three-phase AC voltage output from the three-phase armature winding. a low-voltage power storage means having one end connected to the output end of the half bridge and the other end connected to one end of the DC output end of the composite bridge and driving a vehicle rated voltage load; and the vehicle three-phase AC A power supply device for a vehicle, comprising: a control means for controlling a generated voltage of a rotating machine.