Switch-type reluctance motor and method to compensate for counter electromotive force

• US 5,663,625 A
• Filed: 06/12/1995
• Issued: 09/02/1997
• Est. Priority Date: 06/14/1994
• Status: Expired due to Fees

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Sato, Takashi, Fujibayashi, Kentaro
• Primary Examiner(s): Sircus, Brian
• Application Number:
  US08/489,985
• Time in Patent Office: 813 Days
• Field of Search: 388/876, 388/928.1, 318/701, 318/254, 318/439
• US Class Current: 318/701
• CPC Class Codes: H02P 25/08 Reluctance motors

Abstract

A switch-type reluctance motor and method to compensate for counter electromotive force. The switch-type reluctance motor includes an actual current detection unit to detect the actual current i of the motor or an electrical angle detection unit to detect the rotor electrical angle θ, a rotation rate detection unit to detect the rotor rotation rate and a counter electromotive force compensation unit to calculate a counter electromotive force compensation value based upon at least one of the actual current and the electrical angle, as well as the rotation rate. A voltage command is compensated with the calculated counter electromotive force compensation value Vc. Thus, counter electromotive force compensation corresponding to changes in the electrical angle θ and/or the current i is performed for the switch-type reluctance motor.

Claims

1. A method of compensating for counter electromotive force for a switch-type reluctance motor to be driven based upon a voltage command, said method comprising the steps of:

determining a rotation rate of the motor and at least one of an actual current value and an electrical angle;

determining a counter electromotive force compensation value based upon the rotation rate and at least one of the actual current value and the electrical angle; and

adding the counter electromotive force compensation value to the voltage command to generate a new voltage command to drive the motor, thereby compensating for the counter electromotive force.

2. A method of counter electromotive force compensation for a switch-type reluctance motor according to claim 1, wherein said step of determining a counter electromotive force compensation value comprises the steps of:

prestoring a plurality of counter electromotive force compensation values in a table based upon rotation rates and the at least one of actual current values and electrical angles as variables; and

reading out the counter electromotive force compensation value from the plurality of counter electromotive forces prestored in the table based upon the determined rotation rate and at least one of the actual current value and the electrical angle.

3. A method of counter electromotive force compensation for a switch-type reluctance motor according to claim 1, wherein said step of determining a counter electromotive force compensation value comprises the steps of:

preestablishing a relational expression for counter electromotive force compensation values using rotation rates and at least one of actual current values and electrical angles of the motor as variables; and

determining the counter electromotive force compensation value using the preestablished relational expression, the determined rotation rate and the at least one of the actual current value and the electrical value.

4. A method of counter electromotive force compensation for a switch-type reluctance motor as claimed in claim 1, wherein said step of determining a counter electromotive force value comprises the steps of:

prestoring a plurality of counter electromotive force compensation values in a table based upon rotation rates and the at least one of actual current values and electrical angles as variables;

determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate; and

reading out the counter electromotive force compensation value from the plurality of counter electromotive force compensation values prestored in the table based upon the determined rotation rate and at least one of the actual current value and the electrical angle, if the excitation is for acceleration or constant speed.

5. A method of counter electromotive force compensation for a switch-type reluctance motor as claimed in claim 1, wherein said step of determining a counter electromotive force value comprises the steps of:

prestoring a plurality of counter electromotive force compensation values in a table based upon rotation rates and the at least one of actual current values and electrical angles as variables;

determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate;

reading out the counter electromotive force compensation value from the plurality of counter electromotive force compensation values prestored in the table based upon the determined rotation rate and at least one of the actual current value and the electrical angle and altering the counter electromotive force compensation value to a smaller value, if the excitation is for deceleration; and

reading out the counter electromotive force compensation value from the plurality of counter electromotive force compensation values prestored in the table based upon the determined rotation rate and at least one of the actual current value and the electrical angle, if the excitation is for acceleration or constant speed.

6. A method of counter electromotive force compensation for a switch-type reluctance motor as claimed in claim 1, wherein said step of determining a counter electromotive force value comprises the steps of:

preestablishing a relational expression for counter electromotive force compensation values using rotation rates and at least one of actual current values and electrical angles of the motor as variables;

determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate; and

determining the counter electromotive force compensation value using the preestablished relational expression, the determined rotation rate and the at least one of the actual current value, and the electrical value, if the excitation is for acceleration or constant speed.

7. A method of counter electromotive force compensation for a switch-type reluctance motor as claimed in claim 1, wherein said step of determining a counter electromotive force value comprises the steps of:

preestablishing a relational expression for counter electromotive force compensation values using rotation rates and at least one of actual current values and electrical angles of the motor as variables;

determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate;

determining the counter electromotive force compensation value using the preestablished relational expression, the determined rotation rate and the at least one of the actual current value and the electrical value and adjusting the counter electromotive force compensation value by multiplying the same by a coefficient, if the excitation if the excitation is for deceleration; and

determining the counter electromotive force compensation value using the preestablished relational expression, the determined rotation rate and the at least one of the actual current value and the electrical value, if the excitation is for acceleration or constant speed.

8. A method of counter electromotive force compensation for a switch-type reluctance motor to be driven based upon a voltage command, said method comprising the steps of:

determining a rotation rate of the motor, an actual current value, and an electrical angle;

determining a counter electromotive force compensation value based upon the motor rotation rate, the actual current value, and the electrical angle; and

adding the counter electromotive force compensation value to the voltage command to generate a new voltage command to drive the motor, thereby compensating for the counter electromotive force.

9. A method of counter electromotive force compensation for a switch-type reluctance motor according to claim 8, wherein said step of determining a counter electromotive force compensation value comprises the steps of:

prestoring a plurality of counter electromotive force compensation values in a table based upon rotation rates, actual current values, and electrical angles as variables; and

reading out the counter electromotive force compensation value from the plurality of counter electromotive force compensation values prestored in the table based upon the determined rotation rate, the actual current value, and the electrical angle.

10. A method of counter electromotive force compensation for a switch-type reluctance motor according to claim 8, wherein said step of determining a counter electromotive force compensation value comprises the steps of:

preestablishing a relational expression for counter electromotive force compensation values using rotation rates, actual current values, and electrical angles of the motor as variables; and

determining the counter electromotive force compensation value using the preestablished relational expression, the determined rotation rate, the actual current value, and the electrical value.

11. A method of counter electromotive force compensation for a switch-type reluctance motor as claimed in claim 8, wherein said step of determining a counter electromotive force value comprises the steps of:

prestoring a plurality of counter electromotive force compensation values in a table based upon rotation rates, actual current values, and electrical angles as variables;

determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate; and

reading out the counter electromotive force compensation value from the plurality of counter electromotive force compensation values prestored in the table based upon the determined rotation rate, the actual current and the electrical angle, if the excitation is for acceleration or constant speed.

12. A method of counter electromotive force compensation for a switch-type reluctance motor as claimed in claim 8, wherein said step of determining a counter electromotive force value comprises the steps of:

restoring a plurality of counter electromotive force compensation values in a table based upon rotation rates, actual current values, and electrical angles as variables;

determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate;

reading out the counter electromotive force compensation value from the plurality of counter electromotive force compensation values prestored in the table based upon rotation rates, actual current values, and electrical angles and altering the counter electromotive force compensation value to a smaller value, if the excitation is for deceleration; and

reading out the counter electromotive force compensation value from the plurality of counter electromotive forces prestored in the table based upon rotation rates, actual current values, and electrical angles, if the excitation is for acceleration or constant speed.

13. A method of counter electromotive force compensation for a switch-type reluctance motor as claimed in claim 8, wherein said step of determining a counter electromotive force value comprises the steps of:

preestablishing a relational expression for counter electromotive force compensation values using rotation rates, actual current values, and electrical angles of the motor as variables;

determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate; and

determining the counter electromotive force compensation value using the relational expression, the determining rotation rate, the actual current value, and the electrical value, if the excitation is for acceleration or constant speed.

14. A method of counter electromotive force compensation for a switch-type reluctance motor as claimed in claim 8, wherein said step of determining a counter electromotive force value comprises the steps of:

preestablishing a relational expression for counter electromotive force compensation values using rotation rates, actual current values, and electrical angles of the motor as variables;

determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate;

determining the counter electromotive force compensation value using the relational expression, the determined rotation rate, the actual current value, and the electrical value and adjusting the counter electromotive force compensation value by multiplying the same by a coefficient, if the excitation if the excitation is for deceleration; and

determining the counter electromotive force compensation value using the relational expression, the determined rotation rate, the actual current value, and the electrical value, if the excitation is for acceleration or constant speed.

15. A switch-type reluctance motor driven based upon a voltage command, comprising:

at least one of actual current detection means for detecting an actual current of said motor and electrical angle detection means for detecting the rotor electrical angle of the motor;

rotation rate detection means for detecting a rotor rotation rate of the motor; and

counter electromotive force compensation means for calculating a counter electromotive force compensation value based upon said rotation rate and the at least one of said actual current and said electrical angle;

wherein the voltage command is used in conjunction with said counter electromotive force compensation value to compensate for a counter electromotive force of the motor.

16. A switch-type reluctance motor driven based upon a voltage command, comprising:

at least one of actual current detection means for detecting an actual current of said motor and electrical angle detection means for detecting a rotor electrical angle of the motor;

rotation rate detection means for detecting a rotor rotation rate of the motor; and

counter electromotive force compensation means for calculating a counter electromotive force compensation value based upon the rotation rate and the at least one of the actual current and the electrical angle; and

means for determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate;

wherein said counter electromotive force compensation means generates the counter electromotive force compensation value if the excitation is for acceleration or constant speed, and the voltage command is used in conjunction with said counter electromotive force compensation value to compensate for a counter electromotive force of the motor.

17. A switch-type reluctance motor driven based upon a voltage command, comprising:

at least one of actual current detection means for detecting an actual current of said motor and electrical angle detection means for detecting a rotor electrical angle of the motor;

rotation rate detection means for detecting a rotor rotation rate of the motor; and

counter electromotive force compensation means for calculating a counter electromotive force compensation value based upon the rotation rate and the at least one of the actual current and the electrical angle; and

means for determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate;

wherein said counter electromotive force compensation means generates a reduced electromotive force compensation value if the excitation is for deceleration and generates the counter electromotive force compensation value if the excitation is for acceleration or constant speed, and the voltage command is used in conjunction with said counter electromotive force compensation value to compensate for a counter electromotive force of the motor.

18. A switch-type reluctance motor driven based upon a voltage command, comprising:

rotation rate detection means for detecting a rotor rotation rate of the motor;

actual current detection means for detecting an actual current of the motor;

electrical angle detection means for detecting a rotor electrical angle of the motor; and

counter electromotive force compensation means for calculating a counter electromotive force compensation value based upon said rotation rate, said actual current and said electrical angle detected by said detection means,

means for determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate;

wherein said counter electromotive force compensation means generates the counter electromotive force compensation value if the excitation is for acceleration or constant speed, and the voltage command is used in conjunction with said counter electromotive force compensation value to compensate for counter electromotive force of the motor.

19. A switch-type reluctance motor driven based upon a voltage command, comprising:

rotation rate detection means for detecting a rotor rotation rate of the motor;

actual current detection means for detecting an actual current of the motor;

electrical angle detection means for detecting a rotor electrical angle of the motor; and

counter electromotive force compensation means for calculating a counter electromotive force compensation value based upon said rotation rate, said actual current and said electrical angle detected by said detection means,

means for determining whether an excitation of a stator of the motor is for deceleration by comparing a speed command with the rotation rate;

wherein said counter electromotive force compensation means generates a reduced electromotive force compensation value if the excitation is for deceleration and generates the counter electromotive force compensation value if the excitation is for acceleration or constant speed, and the voltage command is used in conjunction with said counter electromotive force compensation value to compensate for counter electromotive force of the motor.

20. A switch-type reluctance motor driven based upon a voltage command, comprising:

rotation rate detection means for detecting a rotor rotation rate of the motor;

actual current detection means for detecting an actual current of the motor;

electrical angle detection means for detecting a rotor electrical angle of the motor; and

counter electromotive force compensation means for calculating a counter electromotive force compensation value based upon said rotation rate, said actual current and said electrical angle detected by said detection means,

wherein the voltage command is used in conjunction with said counter electromotive force compensation value to compensate for counter electromotive force of the motor.