Reluctance-type electric motor

• US 5,138,244 A
• Filed: 04/02/1991
• Issued: 08/11/1992
• Est. Priority Date: 08/03/1989
• Status: Expired due to Fees

• Current Assignee: Kabushikigaisha Sekogiken
• Original Assignee: Kabushikigaisha Sekogiken
• Inventors: Bahn, Itsuki
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Cabeca, John W.
• Application Number:
  US07/651,254
• Time in Patent Office: 497 Days
• Field of Search: 318/701, 318/798, 318/799, 318/807, 318/809, 318/139, 318/254, 318/811, 318/439
• US Class Current: 318/701
• CPC Class Codes: H02P 25/089 Sensorless control direct torque control H02P23/30

Abstract

A reluctance-type motor which is used as a drive source of industrial equipment, and particularly as a servo motor, wherein an armature current is held at a preset value by chopper control in a section where a position detecting signal is present. Stored magnetic energy of an armature coil is converted to the stored magnetic energy of an armature coil to be energized next, thereby rapidly extinguishing the discharge current and simultaneously making the rise of the energization current of the next armature coil rapid. Accordingly, a motor of a highspeed and torque can be provided. Power is supplied from a D.C. power supply via a forwardly connected diode, and if necessary, a capacitor connected in parallel with the power supply can be additionally used.

Claims

1. A two-phase reluctance-type motor having armature coils of each phase energized with a fixed current, a torque becomes maximum in the vicinity of an electrical angle of 10 to 20 degrees when salient poles of the rotor start to enter magnetic poles and thereafter a flat torque is obtained only for a predetermined section, for removing ripple torque, comprising:

a position detecting unit including position detecting elements for detecting the positions of the salient poles, first, second, third and fourth single-phase position detecting signals are obtained including continuous position detecting signals having an electrical angle width of 90 degrees and not superposed in time;

semiconductor switching elements connected in series and connected to both ends of 1st, 1st, and 2nd and 2nd armature coils when armature coils of first and second phases are formed into said 1st and 1st armature coils and said 2nd and 2nd armature coils, respectively;

diodes, reversely connected to said respective semiconductor switching elements and said armature coils;

an energization control circuit, connected to said semiconductor switching elements, for making said semiconductor switching elements conductive by said 1st, 2nd, 3rd and 4th position detecting signals to energize said 1st, 2nd, 1st and 2nd armature coils, thereby generating an output torque in one direction;

a D.C. power supply for supplying power to said energization control circuit via a diode forwardly inserted in a positive or negative electrode side of said D.C. power supply;

means for adjusting fixing positions of said position detection elements to initiate the energization of each of said armature coils from the vicinity where the torque becomes maximum;

a chopper circuit for holding the armature current at a preset value; and

an electric circuit which, when said armature coil controlled for energization by a position detecting signal is de-energized at the end of said position detecting signal, prevents the magnetic energy stored in said armature coil from being fed back to said D.C. power supply via the reversely connected diodes by means of one diode forwardly inserted in the power supply side, and converts said magnetic energy to the stored magnetic energy of said armature coil to be energized next, thereby making the rise and fall of the armature current rapid.

2. A three-phase reluctance-type motor including a rotor, when armature coils of each phase are energized with a fixed current, a torque becomes maximum in the vicinity of an electric angle of 10 to 20 degrees when salient poles of the rotor start to enter magnetic poles and thereafter a flat torque is obtained only for a predetermined section, for removing ripple torque, comprising:

a position detecting unit including position detecting elements for detecting the positions of the salient poles by A-phase position detecting signals having disposed therein continuous 1st, 2nd and 3rd position detecting signals having an electrical angle width of 120 degrees and not superposed in time are obtained, and by B-phase position detecting signals having disposed therein 4th, 5th and 6th position detecting signals that have an electrical angle phase difference of 60 degrees from the 1st, 2nd and 3rd position detecting signals;

semiconductor switching elements connected to both ends of 1st, 1st, 2nd, 2nd, 3rd and 3rd armature coils corresponding to said armature coils of first, second and third phases, respectively;

diodes reversely connected to said respective semiconductor switching elements and said armature coils;

a first energization control circuit for energizing said semiconductor switching elements by said 1st, 2nd and 3rd position detecting signals to energize said 1st, 2nd and 3rd armature coils, respectively, thereby generating an output torque in one direction;

a second energization control circuit for making said semiconductor switching elements conductive by said 4th, 5th and 6th position detecting signals to energize said 1st, 2nd and 3rd armature coils, respectively, thereby generating a torque in the same direction;

a D.C. power supply for supplying power to said first and second energization control circuits via first and second diodes which are forwardly inserted in a positive or negative electrode side of said D.C. power supply;

means for adjusting fixing positions of said position detecting elements to initiate the energization of each of said armature coils from the vicinity where the torque becomes maximum;

a chopper circuit for holding the armature current at a preset value; and

an electric circuit which, when said armature coils are energized by said 1st, 2nd and 3rd position detecting signals and are de-energized at the end of said position detecting signals, prevents the magnetic energy stored in said armature coils from being fed back to said D.C. power supply via said reversely connected diodes by means of said first diode, and converts said magnetic energy to the stored magnetic energy of said armature coil to be energized next, and which, when said armature coils are energized by said 4th, 5th and 6th position detecting signals and are de-energized at the end of said position detecting signals, prevents the magnetic energy stored in said armature coils from being fed back to said D.C. power supply via said reversely connected diodes by means of said second diode, and converts said magnetic energy to the magnetic energy of said armature coil to be energized next, thereby making the rise and fall of said armature current rapid.