High-speed motor

• US 5,274,287 A
• Filed: 11/05/1992
• Issued: 12/28/1993
• Est. Priority Date: 03/07/1991
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Kabushikigaisha Sekogiken
• Inventors: Bahn, Itsuki
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): NGUYEN, MATTHEW VAN
• Application Number:
  US07/946,445
• Time in Patent Office: 418 Days
• Field of Search: 310/68 R, 310/68 B, 310/71, 310/72, 310/106, 310/156, 310/166, 310/254, 310/256, 310/261, 310/262, 310/269, 318/138, 318/439, 318/685, 318/696, 318/254, 318/701
• US Class Current: 310/68.00B
• CPC Class Codes: H02P 25/089 Sensorless control direct torque control H02P23/30

Abstract

The object of the present invention is to obtain a motor capable of producing a large torque and operating with good efficiency in a high-speed region. A reluctance type motor according to the present invention, when one armature coil (32a) is deactivated through one switching element connected to a negative voltage terminal, prevents the magnetic energy stored in the magnetic core from returning to the electric power source by means of a back-flow preventing diode (21a). The magnetic energy is used to charge a small-capacitance capacitor (47a) to hold it to a high voltage. Thus, a trailing-off of current becomes steep. After a predetermined time has elapsed, a next armature coil (32e) is activated. As an applied voltage is a high voltage charged in the capacitor, the exciting current builds up sharply. Since the building-up and the trailing-off of the exciting current of the armature coil can be made sharp, the rotational speed can also be increased up to several 10 thousand rpm. Furthermore, the inductance coil is activated when the armature coil is activated. When both the armature coil and the inductance coil are deactivated, magnetic energies stored in both coils are discharged into the capacitor to charge it. Then, the energy thus charged in the capacitor is used to compensate the energy loss caused by copper loss and iron loss.

Claims

1. A high-speed three-phase half-wave current supply mode reluctance type motor including a fixed armature and a magnetic rotor, characterized by comprising:

a plurality of salient poles with the same widths, disposed on an outer surface of the magnetic rotor and mutually spaced at regular intervals of the same angle;

6n pieces (n;

a positive integer) of magnetic pole protruding from an inner peripheral surface of the fixed armature to face said salient poles through slight gaps, said magnetic poles, disposed at regular intervals and having the same circumferential width of 120 degrees or 180 degrees by electrical angle, to be wound by an associated armature coil, each pair of which are symmetrically disposed and have the same phase;

No.1-, No.2- and No.3-phase armature coils associated with said magnetic poles;

a position detecting device including a plurality of position detecting elements for detecting rotational positions of said salient poles and generating rectangular-waveform No.1-phase position detecting signals having the same width of 120 degrees by electrical angle and a phase difference of 360 degrees by electrical angle therebetween, and rectangular-waveform No.2- and No.3-phase position detecting signals having the same width and phase difference as the No.1-phase position detecting signals but being successively delayed one another from the No.1-phase position detecting signals by an electric angle of 120 degrees;

a switching element connected to both ends of each armature coil;

first diodes inversely connected to a negative voltage terminal of a DC electric power source in parallel with serial joint units each consisting of said switching element and its corresponding armature coil, and second diodes each having one end inversely connected to a negative voltage terminal of said armature coil;

first, second and third current supply control circuits for supplying currents to said No.1-, No.2- and No.3-phase armature coils through third, fourth and fifth back-flow preventing diodes respectively connected to the DC electric power source in a forward direction, by turning on said switching elements connected to both ends of the armature coils in response to said No.1-, No.2- and No.3-phase position detecting signal;

first, second and third capacitors having small capacitances for storing magnetic energies discharged from said No.1-, No.2- and No.3-phase armature coils through said first and second diodes each having one end being inversely connected to the negative voltage terminal and included in the first, second and third current supply control circuits respectively, when these armature coils are deactivated;

an electric circuit for supplying electrostatic energy charged in the first capacitor to the No.3-phase armature coil when the No.3-phase armature coil is activated, and supplying electrostatic energies charged in the third and second capacitors to the No.2-phase and No.1-phase armature coils when the No.2-phase and No.1-phase armature coils are activated respectively; and

a means for fixing said position detecting elements on the side of the fixed armature so that said armature coils wound around said magnetic poles can be activated at a predetermined point within an electric angle of approximately 30 degrees beginning from a point at which said salient poles start entering said magnetic poles.

2. A high-speed motor in accordance with claim 1, further comprising an inductance coil which is supplied with current corresponding to first halves of said No.1-, No.2- and No.3-phase position detecting signals, and an electric circuit for converting magnetic energy stored in said inductance coil into electrostatic energy of said first, second and third capacitors when said inductance coil is deactivated.

3. A high-speed a three-phase full-wave current supply mode reluctance type motor including a fixed armature and a magnetic rotor, characterized by comprising:

a plurality of salient poles having the same widths, disposed on an outer surface of the magnetic rotor at regular intervals and the equal angles;

12n pieces (n;

a positive integer) of magnetic pole protruding from an inner peripheral surface of the fixed armature to face said salient poles through slight gaps, said magnetic poles, disposed at regular intervals and having the same circumferential width of 120 degrees or 180 degrees by electrical angle, to be wound with an associated armature coil, each pair of which are symmetrically disposed and have the same phase;

armature coils wound around said magnetic poles;

a position detecting device including a plurality of position detecting elements for detecting rotational positions of said salient poles, as well as for generating rectangular-waveform No.1-phase position detecting signals having the equal widths by an electric angle of 120 degrees and a phase difference by an electric angle of 360 degrees therebetween, rectangular-waveform No.2- and No.3-phase position detecting signals having the same width and phase difference as the No.1-phase position detecting signals but being successively delayed from one another from the No.1-phase position detecting signals by an electric angle of 120 degrees, further a rectangular-waveform No.1-phase position detecting signals having the same width and phase difference as the No.1-phase position detecting signals but being delayed from said No.1-phase position detecting signals by an electric angle of 180 degrees, and rectangular-waveform No.2- and No.3-phase position detecting signals having the same width and phase difference as the No.1-phase position detecting signals but being successively delayed from another from the No.1-phase position detecting signals by an electric angle of 120 degrees;

a pair of armature coils to be activated with No.1-phase half-wave current, which are referred to as No.1 and No.1 armature coils, and pairs of armature coils to be activated with No.2-phase and No.3 phase half-wave currents, which are respectively referred to as No.2 and No.2 armature coils, and No.3 and No.3 armature coils;

a switching element connected to both ends of each armature coil;

first diodes inversely connected at a negative voltage terminal of a DC electric power source in parallel with serial joint units each consisting of said switching element and its corresponding armature coil, and second diodes each having one end inversely connected to a negative voltage terminal of said armature coil;

a first electric circuit for turning on the switching elements connected to both ends of said No.1-, No.2- and No.3-armature coils wound round said magnetic poles of the fixed armature in response to said No.1-, No.2- and No.3-phase position detecting signals, as well as for turning on the switching elements connected with both ends of said No.1-, No.2- and No.3-armature coils wound round other magnetic poles of the fixed armature in response to said No.1-, No.2- and No.3-phase position detecting signals, respectively;

first and second current supply control circuits for supplying currents, by turning on said switching elements, to said No.1-. No.2-, No.3-armature coils and No.1-, No.2-, No.3-armature coils through third, fourth, - - - and eighth back-flow preventing diodes, respectively connected to the DC electric power source in a forward direction;

No.1-, No.2-, No.3-, No.1-, No.2- and No.3-capacitors with small capacitances for storing magnetic energies discharged from said No.1-, No.2-, No.3-phase armature coils and said No.1-, No.2-, No.3-phase armature coils through said first and second diodes, each having one end inversely connected to the negative voltage terminal and included in the first and second current supply control circuits when said No.1-, No.2- and No.3-phase armature coils and said No.1-, No.2- and No.3-phase armature coils are deactivated, respectively;

a second electric circuit for supplying electrostatic energies charged in the No.1- and No.1-capacitors to the No.3- and No.3-phase armature coils when the No.3- and No.3-phase armature coils are activated, for supplying electrostatic energies charged in the No.3- and No.3-capacitors to the No.2- and No.2-phase armature coils when the No.2- and No.2-phase armature coils are activated, and further for supplying electrostatic energies charged in the No.2- and No.2-capacitors to the No.1- and No.1-phase armature coils when the No.1- and No.1-phase armature coils are activated; and

a means for fixing said position detecting elements on the fixed armature so that said armature coils wound round said magnetic poles can be activated at a point corresponding to predetermined angle within approximately 30 degrees by electrical angle after said salient poles begin to enter said magnetic poles.

4. A high-speed motor in accordance with claim 3 further comprising a first inductance coil which is supplied with current corresponding to first halves of said No.1-, No.2- and No.3-phase position detecting signals, a second inductance coil which is supplied with current corresponding to first halves of said No.1-, No.2- and No.3-phase position detecting signals, and an electric circuit for converting magnetic energy stored in said first inductance coil into electrostatic energies of said No.1-, No.2- and No.3-capacitors when said first inductance coil is deactivated and further converting magnetic energy stored in said second inductance coil into electrostatic energies of said No.1-, No.2-, and No.3-capacitors when said second inductance coil is deactivated.

5. A high-speed three-phase full-wave current supply mode DC motor including a fixed armature and a magnet rotor, characterized by comprising:

No.1-, No.2- and No.3-phase armature coils associated with magnetic poles of the armature;

said armature coils including an armature coil referred to as a No.1-phase armature coil of No.1-phase normal-direction current supply mode, an armature coil referred to as a No.1-phase armature coil of No.1-phase reverse-direction current supply mode, armature coils being referred to as No.2- and No.3-phase armature coils of No.2-phase and No.3-phase normal-direction current supply modes, and armature coils referred to as No.2- and No.3-phase armature coils of No.2-phase and No.3-phase reverse-direction current supply modes;

a position detecting device including a plurality of position detecting elements for detecting rotational positions of N- and S-poles of said magnet rotor, and generating rectangular-waveform No.1-phase position detecting signals having the same width by an electric angle of 120 degrees and a phase difference by an electric angle of 360 degrees therebetween, and rectangular-waveform No.2- and No.3-phase position detecting signals having the same width and phase difference as the No.1-phase position detecting signals but successively delayed one another from the No.1-phase position detecting signals by an electric angle of 120 degrees and further rectangular-waveform No.1-phase position detecting signals having the same width and phase difference as the No.1-phase position detecting signals but delayed from said No.1-phase position detecting signals by an electric angle of 180 degrees, and rectangular-waveform No.2- and No.3-phase position detecting signals having the same width and phase difference as the No.1-phase position detecting signals but successively delayed one another from the No.1-phase position detecting signals by an electric angle of 120 degrees;

a switching element connected to both ends of each armature coil;

first diodes inversely connected to a negative voltage terminal of a DC electric power source in parallel with serial joint units each consisting of said switching element and its corresponding armature coil, and second diodes each having one end being inversely connected to a negative voltage terminal of said armature coil;

a first electric circuit for turning on the switching elements connected to both ends of said No.1-, No.2- and No.3-armature coils in response to said No.1-, No.2- and No.3-phase position detecting signals, and further turning on the switching elements connected to both ends of said No.1-, No.2- and No.3-armature coils in response to said No.1-, No.2- and No.3-phase position detecting signals, respectively;

first and second current supply control circuits, for supplying currents to said No.1-, No.2-, No.3-armature coils and No.1-, No.2-, No.3-armature coils through third, fourth, - - - and eighth back-flow preventing diodes, respectively connected to the DC electric power source in a forward direction, by turning on said switching elements;

No.1-, No.2-, No.3-, No.1-, No.2- and No.3-capacitors with small capacitances for storing magnetic energies discharged from said No.1-, No.2-, No.3-phase armature coils and said No.1-, No.2-, No.3-phase armature coils through said first and second diodes, each having one end inversely connected to the negative voltage terminal and included in the first and second current supply control circuits, when said No.1-, No.2-, No.3-phase armature coils and said No.1-, No.2-, No.3-phase armature coils are deactivated respectively;

a second electric circuit for supplying electrostatic energies charged in the No.1- and No.1-capacitors to the No.3- and No.3-phase armature coils when the No.3- and No.3-phase armature coils are activated, for supplying electrostatic energies charged in the No.3- and No.3-capacitors to the No.2- and No.2-phase armature coils when the No.2- and No.2-phase armature coils are activated, and further for supplying electrostatic energies charged in the No.2- and No.2-capacitors to the No.1- and No.1-phase armature coils when the No.1- and No.1-phase armature coils are activated; and

a means for fixing said position detecting elements on the fixed armature so that an output torque generated by activations of respective armature coils becomes a maximum value.

6. A high-speed plural-phase reluctance type motor including a fixed armature and a magnetic rotor, characterized by comprising:

a plurality of salient poles, each having the same width and disposed on an outer surface of the magnetic rotor, and being mutually spaced at regular intervals of the same angle;

2n pieces (n;

a positive integer not less than

     3) of magnetic pole protruding from an inner peripheral surface of the fixed armature to face said salient poles through slight gaps, said magnetic poles, disposed at regular intervals and having the same circumferential width of 120 degrees or 180 degrees by electric angle, to be wound with an associated armature coil, each pair of which are symmetrically disposed and have the same phase;

plural-phase armature coils associated with said magnetic poles;

a position detecting device for detecting rotational positions of said salient poles and generating plural-phase position detecting signals;

one switching element connected to each armature coil on the side of a negative terminal of an electric power source;

a first diode connected, in a normal direction, to the armature coil on the side of a positive terminal of the electric power source;

a DC electric power source for supplying electric power to a serial joint unit consisting of said first diode, said armature coil and the switching element;

a current supply control circuit for activating plural-phase armature coils to generate an output torque by turning on said switching elements connected to respective armature coils, in response to said plural-phase position detecting signals;

a first electric circuit for discharging magnetic energy stored in said armature coils through second diodes, each connected between the armature coil and the switching element, and storing them in a small-capacitance capacitor when the switching element is turned off at a terminal end of the position detecting signal so that armature current of the armature coil can be decreased steeply; and

a second electric circuit for supplying electrostatic energy charged in the small-capacitance capacitor to the armature coil through a semiconductor element to be turned on in response to the position detecting signal when the armature coil is activated in response to the position detecting signal after a predetermined time has elapsed so that the armature current builds up sharply.

7. A high-speed motor in accordance with claim 6, further comprising an inductance coil to be supplied with current by a width predetermined from beginning point of plural-phase position detecting signals, and a third electric circuit for converting magnetic energy stored in said inductance coil into electrostatic energy of said small-capacitance capacitor when said inductance coil is deactivated so that the electrostatic energy is held to a value added with electrostatic energy converted from the magnetic energy stored in the armature coils, thereby compensating copper loss of the armature coils, and iron loss of the magnetic core respectively occurring when the magnetic energy is transferred between the armature coils, as well as sharpening a building-up of the armature current of the armature coil.

8. A high-speed motor in a plural-phase DC motor including a fixed armature and a magnet rotor, characterized by comprising:

a plurality of N- and S-magnetic poles each having the same width and alternately disposed to be N- or S-pole on an outer surface of the magnet rotor;

3n pieces (n;

a positive integer not less than

     3) of field magnetic pole disposed to face said N- and S-magnetic poles through slight gaps, said field magnetic poles, disposed at regular intervals and having the same circumferential width of 120 degrees-180 degrees by electric angle, to be wound with an electric angle of 120 degrees-180 degrees;

plural-phase armature coils of bifilar winding associated with said magnetic poles;

a position detecting device including a plurality of position detecting elements for detecting rotational positions of said N- and S-magnetic poles, and for generating rectangular-waveform No.1-phase position detecting signals having the same width by an electric angle of 120 degrees and a phase difference by an electric angle of 360 degrees therebetween, and rectangular-waveform No.2- and No.3-phase position detecting signals having the same width and phase difference as the No.1-phase position detecting signals but being successively delayed one another from the No.1-phase position detecting signals by an electric angle of 120 degrees;

one switching element connected, in a normal direction to each armature coil on the side of a negative terminal of an electric power source;

a first diode connected to the armature coil on the side of a positive terminal of the electric power source;

a DC electric power source for supplying electric power to a serial joint unit consisting of said first diode, said armature coil and the switching element;

a current supply control circuit for activating No.1-, No.2- and No.3-phase armature coils to generate an output torque by turning on said switching elements connected to respective armature coils in response to No.1-, No.2- and No.3-phase position detecting signals;

a first electric circuit for discharging magnetic energy stored in said armature coils through second diodes, each connected between the armature coil and the switching element, and storing them in a small-capacitance capacitor when the switching element is turned off at a terminal end of the position detecting signal so that armature current of the armature coil can be decreased steeply; and

a second electric circuit for supplying electrostatic energy charged in the small-capacitance capacitor to the armature coil through a semiconductor element to be turned on in response to the position detecting signal when the armature coil is activated in response to the position detecting signal after a predetermined time has elapsed so that the armature current builds up sharply.

9. A high-speed motor in a plural-phase reluctance type stepping motor including a fixed armature and a magnetic rotor, characterized by comprising:

a plurality of salient poles, each having the same width and disposed on an outer surface of the magnetic rotor and mutually spaced at regular intervals of the same pitch;

2n pieces (n;

a positive integer not less than

     3) of magnetic pole protruding from an inner peripheral surface of the fixed armature to face said salient poles through slight gaps, said magnetic poles, disposed at regular intervals and with the same circumferential width of 120 degrees or 180 degrees by electric angle, to be wound with an associated armature coil, each pair of which are symmetrically disposed and have the same phase;

plural-phase armature coils associated with said magnetic poles;

a pulse oscillator and a pulse distributer for generating plural-phase stepping electric signals consisting of electric signals, having an electric angle width of 180 degrees, and spaced one another by 180 degrees and electric signals offset from said electric signals by a predetermined phase difference;

one switching element connected to each armature coil on the side of a negative terminal of an electric power source;

a first diode connected, in a normal direction, to the armature coil on the side of a negative terminal of the electric power source;

a DC electric power source for supplying electric power to a serial joint unit consisting of said first diode, said armature coil and the switching element;

a current supply control circuit for activating plural-phase armature coils to generate a stepping output torque by turning on said switching elements connected to respective armature coils, in response to said plural-phase stepping electric signals;

a first electric circuit for discharging magnetic energy stored in said armature coils through second diodes, each connected between the armature coil and the switching element, and storing them in a small-capacitance capacitor when the switching element is turned off at a terminal end of the position detecting signal so that armature current of the armature coil can be decreased steeply; and

a second electric circuit for supplying electrostatic energy charged in the small-capacitance capacitor to the armature coil through a semiconductor element to be turned on in response to the stepping electric signal when the armature coil is activated in response to a next arriving stepping electric signal so that the armature current can be built up sharply.

10. A high-speed motor in accordance with claim 9, further comprising an inductance coil which is supplied with current by widths predetermined from beginning points of plural-phase stepping electric signals, and a third electric circuit for converting magnetic energy stored in said inductance coil into electrostatic energy of said small-capacitance capacitor when said inductance coil is deactivated, so that the electrostatic energy is held to a value added with electrostatic energy converted from the magnetic energy stored in the armature coils, thereby compensating copper loss of the armature coils and iron loss of the magnetic core respectively occurring when the magnetic energy is transferred between the armature coils, as well as sharpening a building-up of the armature current of the armature coil.