Stepping motor

• US 5,231,342 A
• Filed: 03/14/1991
• Issued: 07/27/1993
• Est. Priority Date: 05/31/1989
• 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): Masih, Karen
• Application Number:
  US07/646,725
• Time in Patent Office: 866 Days
• Field of Search: 318/685, 318/696
• US Class Current: 318/696
• CPC Class Codes: H02P 25/089 Sensorless control direct torque control H02P23/30

Abstract

The present invention is a stepping motor used as a driving source for stepping movement of autmatic-machine members. Diodes are connected to the terminal side of a DC power source in a forward direction to prevent accumulated magnetic energy from returning to the power source. A high-voltage large current due to reduction of magnetic energy rushes into an exciting coil to be excited, the magnetic energy of the exciting coil quickly decreases, and a high-speed stepping operation is exeuted. Moreover, the digital signal of each address in a ROM corresponding to the number of steps is read, the read digital signal is converted into an analog signal, acceleration is executed by the frequency of the stepping electric signal corresponding to the frequency proportional to the analog signal for the shortest time without outstepping, and deceleration is executed for the shortest time by reading the ROM backward when the number of steps is halved.

Therefore, the numerical control of load movement can be executed for a shortest time without outstepping.

Claims

1. A stepping motor comprising:

an n-phase (n=2, 3, 4, . . . ) full-wave rotor having salient poles;

n-phase exciting coils installed on n-phase magnetic poles;

semiconductor switching devices connected to both sides of first, second, third, . . . , and n-th phase exciting coils configured into first and first-bar exciting coils, second and second-bar exciting coils, third and third-bar exciting coils, . . . , and n-th and nth-bar exciting coils, respectively;

diodes respectively inversely connected to a series connection respectively comprising said n-phase exciting coils and a transistor switch;

a DC power source applying voltage to said exciting coils through said semiconductor switching devices;

a first backflow-preventive diode, said first and first bar exciting coils connected to a positive or negative terminal of said DC power source through said first backflow-preventive diode;

an excitation control circuit including said second and second-bar exciting coils, said third and third-bar exciting coils, . . . , and n-th and n-th-bar exciting coils respectively excited by similarly-connected second, third, . . . , and n-th backflow-preventive diodes, and the first, second, . . . , and n-th small capacity condensers connected between the positive and negative poles of said DC power source together with the back-flow-preventive diodes;

a specified-frequency n-phase full-wave stepping electric-signal generator;

a first electric circuit generating a stepping torque by electrifying the semiconductor switching devices connected to respectively-corresponding said first, second, third, . . . , and n-th phase exciting coils by said stepping electric signal; and

a stepping electric-signal generator, said stepping electric-signal generator comprising;

a ROM including a digital memory;

a memory circuit memorizing a specified number of steps;

first and second counting circuits;

a second electric circuit, operatively connected to said first and second counting circuits, inputting said specified number of steps of said first counting circuits, inputting said specified number of steps to said first counting circuit and half said number of specified steps to said second counting circuit;

a third electric circuit for starting subtraction of said first and second counting circuits according to said number of specified steps, reading digital memory stores in said ROM, and inversely reading said digital memory of said ROM by a zero-count output signal from said second counting circuit when the stepping motor starts;

an oscillation circuit, connected to said ROM, converting the read signal from said ROM into an analog signal to obtain a frequency of oscillation pulse proportional to said analog signal;

a pulse distributor outputting n-phase full- or half-wave stepping electric signals by inputting the frequency of the output oscillation pulse from said oscillation circuit; and

a third electric circuit, connected to said pulse distributor, for starting input of the output stepping electric signal from said pulse distributor to said excitation control circuit by a driving start command electric signal of the reluctance-type stepping motor and to stop inputting the oscillation-circuit pulse to said pulse distributor when said first counting circuit counts zero.

2. A stepping motor comprising:

an n-phase (n=3, 4, 5, . . . ) half-wave rotor having salient poles;

n-phase exciting coils installed on n-phase magnetic poles;

semiconductor switching devices connected to both sides of first, second, third, . . . , and n-th phase exciting coils;

diodes respectively inversely connected to a series connection comprising said n-phase exciting coils and a transistor switch;

a DC power source, operatively connected to said exciting coils, for applying voltage to said exciting coils through said semiconductor switching devices;

first, second, third, . . . , nth backflow-preventive diodes connected to a positive or negative pole of said DC power source in a forward direction and to said semiconductor switching devices for exciting said respective exciting coils;

first, second, third, . . . , n-th small capacity condensers connected between the positive and negative poles of said DC power source together with said first, second, third, . . . , nth backflow-preventive diodes;

an excitation control circuit including said second, third, . . . , and n-th backflow-preventive diodes, and first, second, third, . . . , and said n-th small capacity condensers;

a specified-frequency n-phase half-wave stepping electric-signal generator;

a first electric circuit generating stepping torque by electrifying said semiconductor switching devices connected to said respectively-corresponding first, second third, . . . , and n-th phase exciting coils by said stepping electric signal; and

a stepping electric-signal generator, comprising;

a ROM including a digital memory;

a memory circuit memorizing a specified number of steps;

first and second counting circuits;

a second electric circuit, operatively connected to said first and second counting circuits, inputting said specified number of steps to said first counting circuit and half said number of specified steps to said second counting circuit;

a third electric circuit for starting subtraction of said first and second counting circuits according to said number of specified steps, reading digital memory stores in said ROM, and inversely reading said digital memory of said ROM by the zero-count output signal from said second counting circuit when the stepping motor starts;

an oscillation circuit, connected to said ROM, converting the read signal from said ROM into an analog signal to obtain a frequency of oscillation pulse proportional to said analog signal;

a pulse distributor outputting n-phase full- or half-wave stepping electric signals by inputting the frequency of the output oscillation pulse from said oscillation circuit; and

a third electric circuit, connected to said pulse distributor, for starting input of the output stepping electric signal from said pulse distributor to said excitation control circuit by a driving start command electric signal of the reluctance-type stepping motor and to stop inputting the oscillation-circuit pulse to said pulse distributor when said first counting circuit counts zero.

3. A stepping motor comprising:

an n-phase (n=2, 3, 4, . . .) full-wave magnet rotor;

n-phase exciting coils installed on n-phase magnetic poles of a fixed armature;

an excitation control circuit including several sets of transistors including exciting coils having various phases;

a DC power source, connected to said excitation control circuit, for applying voltage to said excitation control circuit;

"n" backflow-preventive diodes connected to said DC power source in a forward direction;

diodes inversely connected in parallel to transistors of said circuit to return magnetic energy to said DC power source when said n-phase exciting coils are turned off;

a first electric circuit, connected to said excitation control circuit, for supplying power to the excitation control circuit and including several sets of transistors through said "n" backflow-preventive diodes;

a specified-frequency n-phase full-wave stepping electric-signal generator;

an apparatus, connected to said excitation control circuit, for generating stepping torque by electrifying said excitation control circuit by said stepping electric signal; and

a stepping electric-signal generator comprising;

a memory circuit for memorizing a specified number of steps;

first and second counting circuits;

a ROM;

a second electric circuit, connected to said memory circuit and said first and second counting circuits, for inputting said specified number of steps to said first counting circuit and half said number of specified steps to said second counting circuit;

a third electric circuit, connected to said first and second counting circuits, for starting subtraction of said first and second counting circuits according to said number of specified steps, reading a digital memory stored in said ROM, and reading backward the digital memory of said ROM by employing a zero-count output signal from said second counting circuit when the stepping motor starts;

an oscillation circuit, connected to said ROM, for converting the read signal of said ROM into an analog signal to obtain a frequency of an oscillation pulse proportional to said analog signal;

a pulse distributor, connected to said oscillation circuit, for outputting n-phase full- or half-wave stepping electric signals by inputting the frequency of the output oscillation pulse of said oscillation circuit and including an output stepping electric signal; and

a fourth electric circuit, connected to said pulse distributor, for starting input to said output stepping electric signal of said pulse distributor to said excitation control circuit of the motor by the driving start command electric signal of the stepping motor and to stop inputting the oscillation-circuit pulse to said pulse distributor when said first counting circuit counts zero.

4. A stepping motor comprising:

an n-phase (n=3, 4, 5, . . . ) half-wave magnet rotor;

n-phase exciting coils installed on n-phase magnetic poles of a fixed armature;

transistors connected to both sides of said exciting coils;

diodes respectively connected to a series connection comprising said n-phase exciting coils and a transistor switch;

a DC power source for applying voltage to said exciting coils through said transistors;

"n" backflow-preventive diodes connected to said DC power source in a forward direction;

an excitation control circuit for respectively electrifying said n-phase exciting coils through "n" backflow-preventive diodes;

"n" condensers having a specified capacity, respectively connected between output sides of said "n" backflow-preventive diodes and a negative pole of said DC power source;

a specified-frequency stepping electric-signal generator;

a first electric circuit, connected to said specified-frequency stepping electric signal generator, for generating stepping torque by electrifying said transistors connected to both sides of respectively-corresponding n-phase exciting coils by said stepping electric signal; and

a stepping electric-signal generator comprising;

a memory circuit for memorizing a specified number of steps;

first and second counting circuits;

a ROM;

a second electric circuit, connected to said memory circuit and said first and second counting circuits, for inputting said specified number of steps to said first counting circuit and half said number of specified steps to said second counting circuit;

a third electric circuit, connected to said first and second counting circuits, for starting subtraction of said first and second counting circuits according to the said number of specified steps, reading a digital memory stored in said ROM, and reading backward the digital memory of said ROM by employing a zero-count output signal from said second counting circuit when the stepping motor starts;

an oscillation circuit, connected to said ROM, for converting the read signal of said ROM into an analog signal to obtain a frequency of an oscillation pulse proportional to said analog signal;

a pulse distributor, connected to said oscillation circuit, for outputting n-phase full- or half-wave stepping electric signals by inputting the frequency of the output oscillation pulse of said oscillation circuit and including an output stepping electric signal; and

a fourth electric circuit, connected to said pulse distributor, for starting into to said output stepping electric signal of said pulse distributor to said excitation control circuit of the motor by the driving start command electric signal of the stepping motor and to stop inputting the oscillation-circuit pulse to said pulse distributor when said first counting circuit counts zero.