Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1991-05-01
1992-05-05
Stephan, Steven L.
Electrical generator or motor structure
Dynamoelectric
Rotary
310166, 318254, 318376, H02K 1100, H02K 1712, H02P 308, H02P 314
Patent
active
051110911
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a reluctance type electric motor which can be used instead of an induction motor and a semiconductor motor (brushless motor) which are well known in the art, and more particularly to a reluctance type electric motor which is effective in a case where forward and reverse rotations are required and which can be used as a servo electric motor and a driving motor for electric cars, for example.
BACKGROUND ART
Since a reluctance type electric motor is large in output torque but low in rotation speed and has other defects, it is seldom put into practice.
Particularly, it is seldom that the reluctance type motor is used in a case where high-speed rotation is required.
Further, there is no case wherein the reluctance type motor is used when both the forward and reverse rotations are required and the electromagnetic braking is necessary.
DISCLOSURE OF THE INVENTION
The first subject of this invention is as follows:
The reluctance type electric motor cannot be formed to have a large number of phases unlike the ordinary commutator motor. This is because the semiconductor circuit of each phase is expensive and use of large number of phases makes it impractical.
Therefore, magnetic energy stored in each magnetic pole becomes large and it takes a long time to discharge and store the magnetic energy, so that it may have a high torque but low speed.
Particularly, in a case of a reluctance type motor having a large output torque, the number of magnetic poles of an armature becomes large and a gap in the magnetic path is small so that stored magnetic energy can be increased, and as a result, the above problem becomes more significant.
It becomes more difficult to solve the problem as the torque is made larger.
The second subject of this invention is as follows:
Since the reluctance type motor has no magnet on a rotor, no electric power is generated during the rotation. Therefore, it is impossible to obtain the electromagnetic braking force and no electromagnetic braking effect can be obtained. At the same time, no regenerative braking force can be obtained.
Therefore, it is difficult to use the reluctance type motor as a driving source for electric cars or a servomotor.
The third subject of this invention is as follows:
According to a general means, in order to prevent generation of counter torque, an energization width is set to be smaller than 180 electrical degrees by starting energization of the exciting coil before a salient pole starts to face a magnetic pole.
Therefore, since the time of interrupting the energization is delayed when the rotating operation is changed to the reverse rotation mode, reduced torque and counter torque are generated so as to change the torque characteristics in the forward and reverse rotation modes.
Accordingly, an object of this invention is to provide an inexpensive reluctance type electric motor of high output power and high speed which is capable of effecting the regenerative braking and is made simple in construction.
This invention is a two-phase reluctance type electric motor capable of effecting the regenerative braking, comprising a position detecting device for detecting positions of salient poles of a rotor by use of a plurality of position detection elements fixed on a fixed armature side with a preset separation angle and deriving an electrical signal having first, second, third and fourth position detection signals of a width of 90 electrical degrees which are cyclically generated to continue to one another without being superposed on one another; first semiconductor switching elements series-connected to both ends of first and second exciting coils and first and second exciting coils in a case where the first and first exciting coils and the second and second exciting coils respectively constitute first- and second-phase exciting coils; first diodes connected in a reverse direction to the series-connected bodies of the first semiconductor switching elements and the exciting coils; an energization control circuit for energizing
REFERENCES:
patent: 4143308 (1979-03-01), Deplante et al.
patent: 4253053 (1981-02-01), Ray et al.
patent: 4763056 (1988-08-01), Byrne et al.
patent: 4896089 (1990-01-01), Kliman et al.
patent: 5012172 (1991-04-01), Sember
Kabushikigaisha Sekogiken
La Balle Clayton
Stephan Steven L.
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