Prime-mover dynamo plants – Electric control – Starting and generating dynamo
Reexamination Certificate
2000-01-07
2001-08-21
Ponomarenko, Nicholas (Department: 2834)
Prime-mover dynamo plants
Electric control
Starting and generating dynamo
C290S032000, C322S046000, C310S113000, C310S114000
Reexamination Certificate
active
06278194
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention pertains to a stator generator for an internal combustion engine or an engine starting motor and generator apparatus adapted to be operated as an electric motor when the engine starts and to be operated as a magneto generator after the engine starts.
BACKGROUND OF THE INVENTION
An internal combustion engine has a magneto generator provided for driving various electrical equipment loads provided in the engine. The magneto generator for the internal combustion engine generally used comprises a flywheel magnet rotor provided on a crank shaft of the engine and a stator having armature coils wound on an armature core. The stator includes an igniting generator coil for driving an ignition system for the internal combustion engine, generator coils for driving a fuel injection device, generator coils for driving electrical equipment loads necessary for operating the engine and generator coils for supplying electric power to lamp loads, a battery and so on.
A ring gear is securely provided on an outer periphery of a peripheral wall of the flywheel magnet rotor and an engine starter motor is provided on an engine case. On an output shaft of the starter motor is provided a pinion gear, which is forwardly moved when the starter motor is driven so as to be meshed with the ring gear whereby the flywheel magnet rotor rotates together with the crank shaft.
As the magnet rotor rotates, the igniting generator coil on the stator has a voltage induced there across and therefore the ignition system for the internal combustion engine ignites and starts the engine.
As noted from the foregoing, the conventional internal combustion engine disadvantageously has a complicated construction because of the ring gear provided on the flywheel for starting the engine as well as the starter motor provided therein.
As disclosed in JP58-63085, a magnet generator provided on a crank shaft of an internal combustion engine has been proposed which is used for a starter generator, but is also operated as a brushless DC motor when the engine starts whereby a peculiar starter motor is omitted.
However, since the starter motor and the magnet generator for charging a battery have different winding specifications necessary for meeting their characteristics, such an idea as one rotary electric machine having a magnet rotor and multi-phase armature coils is operated as the brushless DC motor and also as the battery charging magnet generator has not been practically used.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the invention to provide a starter generator for an internal combustion engine serving as a starter motor when the engine starts so as to provide a high torque necessary for starting the engine and as a magnet generator after the engine starts so as to provide a high output even though the engine still rotates at low speed.
In accordance with the present invention, there is provided a starter generator for an internal combustion engine comprising a rotary electric machine including a magnet rotor having a magnet field of 2
m
(
m
is an integral number of more than one) rotor magnetic poles and a stator having an armature core with a plurality of teeth arranged in a peripheral direction and
n
(
n
is an integral number of more than two) phase armature coils of coil groups wound on the teeth of the armature core and connected to each other so as to form an
n
phase circuit so that leading ends of the teeth of the armature core form stator magnetic poles facing the rotor magnetic poles; an inverter circuit to control a current flowing through the armature coils of the rotary electric machine; and an inverter controller to control the inverter circuit whereby the rotary electric machine is operated as an electric motor when the engine starts so as to rotate the magnet rotor in a direction in which the engine starts and the rotary electric machine is operated as a magneto generator after the engine starts so as to flow a charging current to a battery via a full-wave rectifier circuit by an induction voltage induced in the
n
phase armature coils.
The inverter circuit used for the starter generator of the invention comprises a switch circuit of 2
n
on-off controllable switch elements connected to each other in an
n
phase bridge form and an
n
phase diode bridge full-wave rectifier circuit formed of 2
n
diodes connected to the 2
n
switch elements in a reversely parallel manner. A pair of DC side terminals of the full-wave rectifier circuit are connected to both terminals of the battery while
n
AC side terminals of the full-wave rectifier circuit are connected to
n
terminals led out from the
n
phase armature coils, respectively.
The inverter controller serves to control the switch elements of the inverter circuit so that a drive current flows from the battery via the switch elements of the inverter circuit while it is transferred to the
n
phase armature coils in a predetermined phase sequence.
In this invention, the magnetic field of the magnet rotor comprises main poles formed of 2
m
circular arc-shaped permanent magnets having a predetermined polar arc angle and 2
m
interpoles having a polar arc angle smaller than the polar arc angle of the main poles and formed of circular arc-shaped magnetic material having a permeability higher than the permanent magnets of the main poles, both of which are alternately arranged in a peripheral direction so that each one of the interpoles is disposed on both sides of the respective main poles.
The inverter controller is so formed as to control the inverter as herein just below mentioned when the rotary electric machine is operated as the motor or as the magneto generator.
More particularly, the inverter controller serves to control the switch elements of the inverter circuit so that when the internal combustion engine starts, each of the main poles and adjacent one of the interpoles located on the side advanced relative to the one main pole in a rotational direction of the magnet rotor serve as one rotor pole for the motor whereby a drive current flows from the battery through the
n
phase armature coils via the inverter circuit in a predetermined phase sequence while an excitation phase of the armature coils is switched at a motor standard excitation phase switch position set so as to have a relationship of a geometrical center position of the magnetic poles of the rotor for the motor and a geometrical center position of the stator magnetic poles at leading ends of the teeth of the armature core on which the respective phase armature coils are wound set relative to each other or at a motor excitation phase switch position having a predetermined control phase angle relative to the motor standard excitation phase switch position so as to rotate the magnet rotor in a direction in which the engine starts.
The inverter controller also serves to control the switch elements of the inverter circuit so that after the internal combustion engine starts, each of the main poles and adjacent one of the interpoles located on the side delayed relative to the one main pole in a rotational direction of the magnet rotor serve as one rotor pole for the generator whereby a control current flows from the battery through the
n
phase armature coils via the inverter circuit in a predetermined phase sequence at a generator standard excitation phase switch position set so as to have a relationship of a geometrical center position of the magnetic pole of the rotor for the generators and a geometrical center position of the stator magnetic poles at leading ends of the teeth of the armature core on which respective phase armature coils are wound set relative to each other or at a generator excitation phase switch position having a predetermined control phase angle relative to the generator standard excitation phase switch position.
The aforementioned inverter controller may comprise position detection means to detect a rotary angle position of the rotor for switching the excitation phase of the armature coils and switch
Inaba Yutaka
Nakagawa Masanori
Kokusan Denki Co. Ltd.
Pearne & Gordon LLP
Ponomarenko Nicholas
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