Reluctance type motor

• US 5,355,069 A
• Filed: 07/14/1992
• Issued: 10/11/1994
• Est. Priority Date: 11/15/1990
• Status: Expired due to Fees

• Current Assignee: Kabushikigaisha Sekogiken
• Original Assignee: Kabushikigaisha Sekogiken
• Inventors: Bahn, Itsuki
• Primary Examiner(s): Ip, Paul
• Application Number:
  US07/910,021
• Time in Patent Office: 819 Days
• Field of Search: 318/701-820, 318/138, 318/139, 318/254, 318/696, 310/166, 310/68 B, 310/254, 310/257, 310/263
• US Class Current: 318/701
• CPC Class Codes: H02P 25/089 Sensorless control direct torque control H02P23/30

Abstract

A reluctance type motor capable of rotating at a high speed with a large output torque includes transistors (20a˜20f) connected to both ends of respective phase exciting coils (39a˜39c), a current supply control circuit for successively activating the exciting coils in response to position detecting signals representing the rotational positions of a rotor, and diodes (21a˜21f) connecting the exciting coils and capacitors (47a˜47c). When a current supply to the exciting coil is stopped, one of the capacitors is promptly charged with the magnetic energy stored in the exciting coil to rapidly extinguish the magnetic energy and also an exciting current supplied to a subsequently activated exciting coil is rapidly built up by use of a charged voltage in the capacitor. The position detecting element is fixed at a required position on an armature, so that an advanced-phase current supply can be made in such a manner that the exciting current is supplied to the exciting coil before salient-poles begin to enter magnetic poles, and is continued during a predetermined large electric angle.

Claims

1. A reluctance type motor driven by a DC electric power source and having a motor main body including a rotor equipped with a plurality of salient-poles and an armature equipped with a plurality of magnetic poles respectively associated with a plurality of exciting coils, said reluctance type motor comprising:

a position detecting device having a number of position detecting elements spaced apart from each other so as to correspond to said plurality of exciting coils, and successively outputting position detecting signals in accordance with a rotational position of the rotor;

a current supply control circuit connected to the DC electric power source for successively activating said exciting coils by supplying respective exciting currents to said exciting coils in response to said position detecting signals;

circuit means having a plurality of capacitors, for promptly discharging a magnetic energy stored in one of said exciting coils into a corresponding one of said plurality of capacitors, as a charged voltage, to charge said one capacitor and rapidly extinguish the magnetic energy stored in said one exciting coil at the moment when the respective exciting current supplied to said one exciting coil is stopped, said circuit means also steeply building up an exciting current supplied to a subsequently activated exciting coil by use of the charged voltage in said one capacitor; and

said number of position detecting elements being disposed such that, an interval before any one of said salient-poles begins to enter any one of said magnetic poles, said current supply control circuit is initiated to supply the respective exciting current to the one of said exciting coils associated with said any one of said magnetic poles, and said position detecting device outputs one of said position detecting signals sufficient for continuing the current supply of the respective exciting current to the one exciting coil during a predetermined large electric angle.

3. The reluctance type motor in accordance with claim 1 or 2, wherein a pair of corresponding magnetic poles of said plurality of magnetic poles are disposed facing each other in a diametric direction of the motor main body, and exciting coils respectively associated with said magnetic poles are activated simultaneously by said current supply control circuit so as to have the same phase.

4. The reluctance type motor in accordance with claim 1 or 2 wherein:

said motor main body comprises an outer casing having an inner surface;

said rotor is rotatably supported by said outer casing; and

said armature is fixed on the inner surface of the outer casing.

5. The reluctance type motor in accordance with claim 1 or 2, in which said rotor has an outer surface, and each of said plurality of salient-poles is formed on an outer surface of the rotor so as to be uniformly spaced with each other in a circumferential direction of the rotor and also to have the same circumferential width as each other.

6. The reluctance type motor in accordance with claim 1 or 2, wherein:

said armature has an inner surface, and each of said plurality of magnetic poles is formed on said inner surface of the armature by being spaced uniformly with each other in a circumferential direction of the armature and having the same circumferential width as each other, as well as being disposed facing said plurality of salient-poles over slight gaps.

7. A reluctance type motor in accordance with claim 1 or 2, wherein:

said current supply control circuit comprises a plurality of switching elements respectively interposed between said DC electric power source and a corresponding one of said exciting coils so that the exciting coils can be successively activated by alternately turning on and off said corresponding switching elements;

said circuit means includes diodes, each diode inversely connected to corresponding said switching elements, and back-flow preventing diodes respectively connected in a forward direction with respect to said DC electric power source; and

said capacitors, respectively interposed between respective said inversely connected diodes and back-flow preventing diodes, are successively charged through said inversely connected diodes.

8. The reluctance type motor in accordance with claim 1 or 2, comprising a chopper circuit stopping the corresponding current supplies to each of said exciting coils when said respective exciting current flowing through said respective exciting coil exceeds an upper limit, as well as for resuming the corresponding current supply when said respective exciting current decreases below a lower limit.

2. A reluctance type motor driven by a DC electric power source and having a motor main body including a rotor equipped with a plurality of salient-poles and an armature equipped with a plurality of magnetic poles respectively associated with a plurality of exciting coils, said reluctance type motor comprising:

a position detecting device having a number of position detecting elements spaced apart from each other so as to correspond to said plurality of exciting coils, and successively outputting a first group of a plurality of position detecting signals and also outputting a second group of said plurality of position detecting signals respectively having opposite phases with respect to said first group of position detecting signals, in accordance with a rotational position of said rotor;

a current supply control circuit being connected to the DC electric power source, successively activating a first group of said plurality of exciting coils in response to said first group of position detecting signals and also successively activating a second group of said plurality of exciting coils in response to said second group of position detecting signals, by supplying respective exciting currents to said plurality of exciting coils;

circuit means, having a plurality of capacitors, for promptly discharging a magnetic energy stored in one of said plurality of exciting coils into a corresponding one of said plurality of capacitors, as a charged voltage, so as to charge said corresponding one capacitor and to rapidly extinguish the magnetic energy stored in said one exciting coil at the moment when the respective exciting current supplied to said one exciting coil is stopped, said circuit means also steeply building up the respective exciting current supplied to a subsequently activated exciting coil by use of the charged voltage in said corresponding one capacitor; and

,

said position detecting elements being disposed in such a manner that, an interval before any one of said salient-poles begins to enter any one of said magnetic poles, the current supply control circuit is initiated to supply the exciting current respectively corresponding to the exciting coil associated with said any one of said magnetic poles, and said position detecting device outputs one of said position detecting signals sufficient for continuing the current supply to the associated exciting coil during a predetermined large electric angle.

9. A three-phase half-wave type reluctance type motor driven by a DC electric power source, said reluctance type motor comprising:

an outer casing having an inner surface;

a rotor having an outer surface formed with a plurality of salient-poles having equal circumferential widths and equally spaced with each other in a circumferential direction, the rotor rotatably supported on the outer casing;

an armature having an inner surface formed with 6 n (n;

a positive integer) pieces of magnetic pole respectively having circumferential widths of one of a 120-and a 180-degree electric angle and equally spaced with each other in the circumferential direction to face said plurality of salient-poles over slight gaps, and first, second and third phase exciting coils respectively associated with said magnetic poles, said armature being fixed on the inner surface of the outer casing;

a position detecting device, having a number of position detecting elements spaced apart from each other so as to correspond to said exciting coils, successively outputting a first phase position detecting signal having a rectangular waveform generating a predetermined signal level of a 120˜

180-degree width at regular intervals of a 360-degree electric angle, a second phase position detecting signal having the same rectangular waveform but delayed by an electric angle of 120 degrees with respect to the first phase position detecting signal and a third phase position detecting signal having the same rectangular waveform but delayed by an electric angle of 120 degrees with respect to the second phase position detecting signal, in accordance with a rotational position of said rotor;

a current supply control circuit including a plurality of switching elements each end of each phase exciting coil serially connected to a respective one of said plurality of switching elements, each of said plurality of switching elements interposed between the DC electric power source and a corresponding one of said first, second and third phase exciting coils, alternately activating and deactivating said first, second and third phase exciting coils by alternately turning on and off said corresponding serially connected switching elements in response to said first, second and third phase position detecting signals, to control exciting currents flowing through respective said first, second and third phase exciting coils, each switching element and corresponding serially connected exciting coil forming a joint unit;

circuit means including diodes respectively connected inversely to said joint units, first, second, and third back-flow preventing diodes respectively connected in a forward direction with respect to the DC electric power source and respectively related to said first, second and third phase exciting coils, and first, second and third capacitors respectively interposed between said inversely connected diodes and said first, second, and third back-flow preventing diodes, said circuit means promptly discharging a magnetic energy stored in one of said exciting coils into a corresponding one of said first, second, and third capacitors, as a charged voltage, through a corresponding one of said inversely connected diodes to charge said corresponding one capacitor and to rapidly extinguish the magnetic energy stored in said one exciting coil at the moment when the respective exciting current supplied to said one exciting coil is stopped, said circuit means also steeply building up the respective exciting current supplied to a subsequently activated exciting coil by use of the charged voltage in said corresponding capacitor;

said position detecting elements being disposed in such a manner that, before any one of said salient-poles begins to enter any one of said magnetic poles, the current supply control circuit is initiated to supply the exciting current respectively corresponding to the exciting coil associated with said any one of said magnetic poles, and said position detecting device outputs one of said detecting signals sufficient for continuing the current supply to the associated exciting coil during a predetermined large electric angle; and

a pair of corresponding magnetic poles of said plurality of magnetic poles being disposed to face each other in a diametric direction of said armature, and the exciting coils respectively associated with said magnetic poles being activated simultaneously by said current supply control circuit so as to have the same phase.

10. A three-phase full wave reluctance type motor driven by a DC electric power source, said high speed reluctance type motor comprising:

an outer casing having an inner surface;

a rotor having an outer surface formed with a plurality of salient poles having equal circumferential widths and equally spaced with each other in a circumferential direction, the rotor rotatably supported on the outer casing;

an armature having an inner surface being formed with 12 n (n;

a positive integer) pieces of magnetic pole respectively having circumferential widths of one of a 120-and a 180-degree electric angle and equally spaced from each other in the circumferential direction to face said plurality of salient poles over slight gaps, and including first through sixth phase exciting coils respectively associated with said magnetic poles, said armature being fixed on the inner surface of the outer casing;

a position detecting device having a number of position detecting elements spaced apart from each other so as to correspond to said phase exciting coils, successively outputting a first phase position detecting signal having a rectangular waveform generating a predetermined signal level of a 120˜

150-degree width at regular intervals of a 360-degree electric angle, a second phase position detecting signal having the same rectangular waveform but delayed by an electric angle of 120 degrees with respect to the first phase position detecting signal, and a third phase position detecting signal having the same rectangular waveform but delayed by an electric angle of 120 degrees with respect to the second phase position detecting signal and also outputting fourth, fifth and sixth phase position detecting signals having opposite phases with respect to said first, second and third phase position detecting signals, respectively, in accordance with a rotational position of said rotor;

a current supply control circuit including a plurality of switching elements, each end of each phase exciting coil serially connected to a respective one of said plurality of switching elements, each of said plurality of switching elements interposed between the DC electric power source and a corresponding one of said first through sixth phase exciting coils, alternately activating and deactivating said first through sixth phase exciting coils by alternately turning on and off said corresponding serially connected switching elements in response to said first through sixth phase position detecting signals, to control exciting currents flowing through respective said first through sixth phase exciting coils, each switching element and corresponding serially connected exciting coil forming a joint unit;

circuit means including diodes respectively connected inversely to said joint units, first, second and third back-flow preventing diodes respectively connected in a forward direction with respect to the DC electric power source and respectively relating to said first and fourth phase exciting coils, said second and fifth phase exciting coils and said third and sixth phase exciting coils, respectively, and first, second and third capacitors respectively interposed between said first, second and third back-flow preventing diodes, said circuit means promptly discharging a magnetic energy stored in one of said exciting coils into a corresponding one of said first, second and third capacitors, as a charged voltage, through a corresponding one of said inversely connected diodes to charge said corresponding one capacitor and to rapidly extinguish the magnetic energy stored in said one exciting coil at the moment when the respective exciting current supplied to said one exciting coil is stopped, said circuit means steeply building up the respective exciting current supplied to a subsequently activated exciting coil by use of the charged voltage in said corresponding one capacitor;

said number of position detecting elements being disposed in such a manner that, before any one of said salient poles begins to enter any one of said magnetic poles, said current supply control circuit is initiated to supply the exciting current respectively corresponding to the exciting coil associated with said any one of said magnetic poles, and said position detecting device outputs one of said position detecting signals sufficient for continuing the current supply of the respective exciting current to the one exciting coil during a predetermined large electric angle;

a pair of corresponding magnetic poles of said 12 n pieces of magnetic pole being disposed facing each other in a diametric direction of said armature, and said exciting coils respectively associated with said magnetic poles being activated simultaneously by said current supply control circuit to have the same phase.

14. The reluctance type motor as in one of claims 9-13, further comprising:

an exciting current detecting circuit for generating detecting signals representing values of actual respective said exciting coils; and

a chopper circuit maintaining each of the exciting currents at a current value corresponding to a standard voltage.

11. A two-phase full-wave reluctance type motor driven by a DC electric power source, said reluctance type motor comprising:

an outer casing having an inner surface;

a rotor having an outer surface formed with a plurality of salient poles having equal circumferential widths, equally spaced with each other in a circumferential direction, the rotor rotatably supported on the outer casing;

an armature having an inner surface formed with 8 n (n;

a positive integer) pieces of magnetic pole respectively having circumferential widths of a 120-degree electric angle and equally spaced from each other in the circumferential direction to face said plurality of salient poles over slight gaps, including first through fourth phase exciting coils, respectively associated with said magnetic poles, said armature being fixed on the inner surface of the outer casing;

a position detecting device, having a number of position detecting elements spaced apart from each other so as to correspond to said exciting coils, successively outputting a first phase position detecting signal having a rectangular waveform generating a predetermined signal level of a 90˜

150-degree width at regular intervals of a 360-degree electric angle, a second phase position detecting signal having the same rectangular waveform but delayed by an electric angle of 90 degrees with respect to the first phase position detecting signal, and also outputting third and fourth phase position detecting signals having opposite phases with respect to said first and second phase position detecting signals, respectively, in accordance with a rotational position of said rotor;

a current supply control circuit including a plurality of switching elements, each end of each exciting coil serially connected to a respective one of said plurality of switching elements, each of said plurality of switching elements interposed between the DC electric power source and a corresponding one of said first through fourth phase exciting coils, alternately activating and deactivating said first through fourth phase exciting coils by alternately turning on and off said corresponding serially connected switching elements in response to corresponding said first through fourth phase position detecting, to control exciting currents flowing through respective said first through sixth phase exciting coils, each switching element and corresponding serially connected exciting coil forming a joint unit;

circuit means including diodes respectively connected inversely to said joint units, first and second back-flow preventing diodes respectively connected in a forward direction with respect to the DC electric power source and respectively relating to said first and third phase exciting coils and said second and fourth phase exciting coils, respectively, and first and second capacitors respectively interposed between said first and second back-flow preventing diodes, said circuit means promptly discharging a magnetic energy stored in one of said exciting coils into a corresponding one of said first and second capacitors, as a charged voltage, through a corresponding one of said inversely connected diodes to charge said corresponding one capacitor and to rapidly extinguish the magnetic energy stored in said one exciting coil at the moment when the respective exciting current supplied to said one exciting coil is stopped, said circuit means steeply building up the respective exciting current supplied to a subsequently activated exciting coil by use of the charged voltage in said corresponding one capacitor;

said number of position detecting elements being disposed in such a manner that, before any one of said salient poles begins to enter any one of said magnetic poles, said current supply control circuit is initiated to supply the exciting current respectively corresponding to the exciting coil associated with said any one of said magnetic poles, and said position detecting device outputs one of said position detecting signals sufficient for continuing the current supply of the respective exciting current to the one exciting coil during a predetermined large electric angle;

a pair of corresponding magnetic poles of said 8 n pieces of magnetic pole being disposed facing each other in a diametric direction of said armature, and said exciting coils respectively associated with said magnetic poles being activated simultaneously by said current supply control circuit to have the same phase.

12. A two-phase full-wave reluctance type motor driven by a DC electric power source, said reluctance type motor comprising:

an outer casing having an inner surface;

a rotor having an outer surface formed with a plurality of salient poles having the same circumferential widths and equally spaced with each other in a circumferential direction, the rotor rotatably supported on the outer casing;

an armature having an inner surface formed with 8 n (n;

a positive integer) pieces of magnetic pole respectively having circumferential widths of a 120- degree electric angle and equally spaced from each other in the circumferential direction to face said plurality of salient poles over slight gaps, including first through fourth phase exciting coils, respectively associated with said magnetic poles, said armature being fixed on the inner surface of the outer casing;

a position detecting device, having a number of position detecting elements spaced apart from each other so as to correspond to said exciting coils, successively outputting a first phase position detecting signal having a rectangular waveform generating a predetermined signal level of a 90˜

150-degree width at regular intervals of a 360-degree electric angle, a second phase position detecting signal having the same rectangular waveform but delayed by an electric angle of 90 degrees with respect to the first phase position detecting signal, and also outputting third and fourth phase position detecting signals having opposite phases with respect to said first and second phase position detecting signals, respectively, in accordance with a rotational position of said rotor;

a current supply control circuit including a plurality of switching elements, each end of each exciting coil serially connected to a respective one of said plurality of switching elements, each of said plurality of switching elements interposed between the DC electric power source and a corresponding one of said first through fourth phase exciting coils, alternately activating and deactivating said first through fourth phase exciting coils by alternately turning on and off said corresponding serially connected switching elements in response to corresponding said first through fourth phase position detecting signals, to control exciting currents flowing through respective said first through sixth phase exciting coils, each switching element and corresponding serially connected exciting coil forming a joint unit;

circuit means including diodes respectively connected inversely to said joint units, first, second, third and fourth back-flow preventing diodes respectively connected in a forward direction with respect to the DC electric power source and respectively relating to said first through fourth phase exciting coils, respectively,, and first, second, third and fourth capacitors respectively interposed between said inversely connected diodes and said first, second, third and fourth back-flow preventing diodes, said circuit means promptly discharging a magnetic energy stored in one of said exciting coils into a corresponding one of said first and second capacitors, as a charged voltage, through a corresponding one of said inversely connected diodes to charge said corresponding one capacitor and to rapidly extinguish the magnetic energy stored in said one exciting coil at the moment when the respective exciting current supplied to said one exciting coil is stopped, said circuit means steeply building up the respective exciting current supplied to a subsequently activated exciting coil by use of the charged voltage in said corresponding one capacitor;

said number of position detecting elements being disposed in such a manner that, before any one of said salient poles begins to enter any one of said magnetic poles, said current supply control circuit is initiated to supply the exciting current respectively corresponding to the exciting coil associated with said any one of said magnetic poles, and said position detecting device outputs one of said position detecting signals sufficient for continuing the current supply of the respective exciting current to the one exciting coil during a predetermined large electric angle;

a pair of corresponding magnetic poles of said 8 n pieces of magnetic pole being disposed facing each other in a diametric direction of said armature, and said exciting coils respectively associated with said magnetic poles being activiated simultaneously by said current supply control circuit to have the same phase.

13. A three-phase full wave reluctance type motor driven by a DC electric power source, said reluctance type motor comprising:

an outer casing having an inner surface;

a rotor having an outer surface formed with a plurality of salient poles having the same circumferential widths and equally spaced with each other in a circumferential direction, the rotor rotatably supported on the outer casing;

an armature having an inner surface formed with 12 n (n;

a positive integer) pieces of magnetic pole respectively having circumferential widths of one of a 120- and a 180-degree electric angle and equally spaced from each other in the circumferential direction to face said plurality of salient poles over slight gaps, including first through sixth phase exciting coils, respectively associated with said magnetic poles, said armature being fixed on the inner surface of the outer casing;

a position detecting device, having a number of position detecting elements spaced apart from each other so as to correspond to said exciting coils, successively outputting a first phase position detecting signal having a rectangular waveform generating a predetermined signal level of a 90-degree width at regular intervals of a 360-degree electric angle, a second phase position detecting signal having the same rectangular waveform but delayed by an electric angle of 120 degrees with respect to the first phase position detecting signal, and a third phase position detecting signal having the same rectangular waveform but delayed by an electric angle of 120 degrees with respect to the second phase position detecting signal and also outputting fourth, fifth and sixth phase position detecting signals having opposite phases with respect to said first, second and third phase position detecting signals, respectively, in accordance with a rotational position of said rotor;

a current supply control circuit including a plurality of switching elements, each end of each exciting coil serially connected to a respective one of said plurality of switching elements, each of said plurality of switching elements interposed between the DC electric power source and a corresponding one of said first through sixth phase exciting coils, alternately activating and deactivating said first through sixth phase exciting coils by alternately turning on and off said corresponding serially connected switching elements in response to corresponding said first through sixth phase position detecting signals, to control exciting currents flowing through respective said first through sixth phase exciting coils, each switching element and corresponding serially connected exciting coil forming a joint unit;

circuit means including diodes respectively connected inversely to said joint units, first and second back-flow preventing diodes respectively connected in a forward direction with respect to the DC electric power source and respectively relating to said first, second and third phase exciting coils, and said fourth fifth and sixth phase exciting coils, respectively, and first and second capacitors respectively interposed between said inversely connected diodes and said and said first and second back-flow preventing diodes, said circuit means promptly discharging a magnetic energy stored in one of said exciting coils into a corresponding one of said first and second capacitors, as a charged voltage, through a corresponding one of said inversely connected diodes to charge said corresponding one capacitor and to rapidly extinguish the magnetic energy stored in said one exciting coil at the moment when the respective exciting current supplied to said one exciting coil is stopped, said circuit means steeply building up the respective exciting current supplied to a subsequently activated exciting coil by use of the charged voltage in said corresponding one capacitor;

said number of position detecting elements being disposed in such a manner that, before any one of said salient poles begins to enter any one of said magnetic poles, said current supply control circuit is initiated to supply the exciting current respectively corresponding to the exciting coil associated with said any one of said magnetic poles, and said position detecting device outputs one of said position detecting signals sufficient for continuing the current supply of the respective exciting current to the one exciting coil during a predetermined large electric angle;

a pair of corresponding magnetic poles of said 12 n pieces of magnetic pole being disposed facing each other in a diametric direction of said armature, and said exciting coils respectively associated with said magnetic poles being activated simultaneously by said current supply control circuit to have the same phase.

15. A reluctance type motor driven by a DC electric power source and having a motor main body including a rotor equipped with a plurality of salient-poles and an armature equipped with a plurality of magnetic poles respectively associated with a plurality of exciting coils, said reluctance type motor comprising:

a position detecting device having a number of position detecting elements spaced apart from each other and successively outputting position detecting signals in accordance with a rotational position of the rotor;

a current supply control circuit connected to the DC electric power source for successively activating said exciting coils by supplying respective exciting currents to said exciting coils in response to said position detecting signals; and

said number of position detecting elements being disposed wherein said current supply control circuit is initiated to supply the respective exciting current to the one of said exciting coils associated with said any one of said magnetic poles an interval before any one of said salient-poles begins to enter any one of said magnetic poles and said position detecting device outputs one of said position detecting signals sufficient for maintaining flow of the respective exciting current to the one exciting coil during a predetermined large electric angle.

16. A reluctance type motor driven by a DC electric power source and having a motor main body including a rotor equipped with a plurality of salient-poles and an armature equipped with a plurality of magnetic poles respectively associated with a plurality of exciting coils, said reluctance type motor comprising:

a position detecting device having a number of position detecting elements spaced apart from each other, and successively outputting a first group of a plurality of position detecting signals and also outputting a second group of said plurality of position detecting signals respectively having opposite phases with respect to said first group of position detecting signals, in accordance with a rotational position of said rotor;

a current supply control circuit being connected to the DC electric power source, successively activating a first group of said plurality of exciting coils in response to said first group of position detecting signals and also successively activating a second group of said plurality of exciting coils in response to said second group of position detecting signals, by supplying respective exciting currents to said plurality of exciting coils; and

,

said position detecting elements being disposed in such a manner that, an interval before any one of said salient-poles begins to enter any one of said magnetic poles, the current supply control circuit is initiated to supply the exciting current respectively corresponding to the exciting coil associated with said any one of said magnetic poles, and said position detecting device outputs one of said position detecting signals sufficient for continuing the current supply to the associated exciting coil during a predetermined large electric angle.