Electric motor control device, method and program

• US 20010026135A1
• Filed: 03/29/2001
• Published: 10/04/2001
• Est. Priority Date: 03/30/2000
• Status: Active Grant

• Current Assignee: Establissements Andre Zalkin
• Original Assignee: Establissements Andre Zalkin
• Inventors: Zalkin, Daniel, Matthys, Philippe, Ostrowski, Laurent
• Granted Patent: US 6,525,498 B2
• Time in Patent Office: Days
• US Class Current: 318/432
• CPC Class Codes: B67B 3/208 Electrical means responsive to the torque applied and acting on motor control means, e.g. strain gauges or power measurement means B67B3/2093 takes precedence
• CPC Class Codes: H02P 5/74 controlling two or more ac dynamo-electric motors H02P5/46, H02P5/60 take precedence
• CPC Class Codes: H02P 6/04 Arrangements for controlling or regulating the speed or torque of more than one motor H02P6/10 takes precedence
• CPC Class Codes: H02P 6/34 Modelling or simulation for control purposes

Abstract

A device for controlling an electric motor measures the current I_m drawn by the motor and the torque C_m supplied by the motor. It includes a power supply 4 for the motor and an initialization unit 16 capable of generating a torque set point C_c and of receiving and processing information relating to the current I_m and the torque C_m to deduce therefrom a relationship between the set point C_c, the torque C_m and the current I_m in order to be able to determine the torque C_m from the set point C_c and the current I_m.

Claims

1. A device for controlling an electric motor, said device including means for measuring the current I_m drawn by said motor, means for measuring the torque C_m supplied by said motor, power supply means for said motor, and an initialization unit capable of generating a torque set point C_c and of receiving and processing information relating to said current I_m and said torque C_m to deduce therefrom a relationship between said set point C_c, said torque C_m and said current I_m in order to be able to determine said torque C_m from said set point C_c and said current I_m.

2. The device claimed in

claim 1

wherein said means for measuring said torque C_m supplied by said motor are removable.

3. The device claimed in

claim 1

further including a calculation unit associated with memory means and a user interface, a first data bus between said initialization unit and said power supply means of said motor, and a second data bus between said initialization unit and said calculation unit.

4. The device claimed in

claim 1

wherein said means for measuring said torque C_m are provided with a removable calibrator.

5. An electromechanical system including a device for controlling an electric motor, said device including means for measuring the current I_m drawn by said motor, means for measuring the torque C_m supplied by said motor, power supply means for said motor, and an initialization unit capable of generating a torque set point C_c and of receiving and processing information relating to said current I_m and said torque C_m to deduce therefrom a relationship between said set point C_c, said torque C_m and said current I_m in order to be able to determine said torque C_m from said set point C_c and said current I_m.

6. The system claimed in

claim 5

wherein said means for measuring said torque C_m supplied by said motor are removable.

7. The system claimed in

claim 5

further including a calculation unit associated with memory means and a user interface, a first data bus between said initialization unit and said power supply means of said motor, and a second data bus between said initialization unit and said calculation unit.

8. The system claimed in

claim 5

wherein said means for measuring said torque C_m are provided with a removable calibrator.

9. A method of controlling an electric motor in which an initialization unit generates a torque set point C_c addressed to power supply means of said motor, current measuring means measure the current I_m drawn by said motor, torque measuring means measure the torque C_m supplied by said motor, said initialization unit receives and processes information relating to said current I_m and said torque C_m to deduce therefrom a relationship between said set point C_m said torque C_m and said current I_m in order to be able to determine said torque C_m from said set point C_c and said current I_m.

10. The method claimed in

claim 9

wherein said torque measuring means are installed beforehand and then removed after measuring at least one value of said torque C_m.

11. The method claimed in

claim 9

wherein said initialization unit generates three torque set point values C_c, said current measuring means measure n values of said current I_m drawn by said motor, where n is greater than 2, said torque measuring means measure n values of said torque C_m supplied by said motor, and said initialization unit receives and processes n values relating to said current I_m and said torque C_m to deduce therefrom a relationship between said set point C_c, said torque C_m and said current I_m in order to be able to determine said torque C_m from only said set point C_c and said current I_m.

12. The method claimed in

claim 11

wherein said initialization unit calculates three coefficients a, b, c of a second order equation relating to said set point C_c and said torque C_m and three coefficients a′

, b′

, c′

of a second order equation linking said current I_m and said torque C_m.

13. A computer program including program code means for implementing the steps of a method of controlling an electric motor in which an initialization unit generates a torque set point C_c addressed to power supply means of said motor, current measuring means measure the current I_m drawn by said motor, torque measuring means measure the torque C_m supplied by said motor, said initialization unit receives and processes information relating to said current I_m and said torque C_m to deduce therefrom a relationship between said set point C_c, said torque C_m and said current I_m in order to be able to determine said torque C_m from said set point C_c and said current I_m.

14. The program claimed in

claim 13

wherein said torque measuring means are installed beforehand and then removed after measuring at least one value of said torque C_m.

15. The program claimed in

claim 13

wherein said initialization unit generates three torque set point values C_c, said current measuring means measure n values of said current I_m drawn by said motor, where n is greater than 2, said torque measuring means measure n values of said torque C_m supplied by said motor, and said initialization unit receives and processes n values relating to said current I_m and said torque C_m to deduce therefrom a relationship between said set point C_c, said torque C_m and said current I_m in order to be able to determine said torque C_m from only said set point C_c and said current I_m.

16. The program claimed in

claim 15

wherein said initialization unit calculates three coefficients a, b, c of a second order equation relating to set point C_c and said torque C_m and three coefficients a′

, b′

, c′

of a second order equation linking said current I_m and said torque C_m .

17. A medium which can be read by a device for reading program code means stored therein and which are adapted to implement the steps of a method of controlling an electric motor in which an initialization unit generates a torque set point C_c addressed to power supply means of said motor, current measuring means measure the current I_m drawn by said motor, torque measuring means measure the torque C_m supplied by said motor, said initialization unit receives and processes information relating to said current I_m and said torque C_m to deduce therefrom a relationship between said set point C_c, said torque C_m and said current I_m in order to be able to determine said torque C_m from said set point C_c and said current I_m.

18. The medium claimed in

claim 17

wherein said torque measuring means are installed beforehand and then removed after measuring at least one value of said torque C_m.

19. The medium claimed in

claim 17

wherein said initialization unit generates three torque set point values C_c, said current measuring means measure n values of said current I_m drawn by said motor, where n is greater than 2, said torque measuring means measure n values of said torque C_m supplied by said motor, and said initialization unit receives and processes n values relating to said current I_m and said torque C_m to deduce therefrom a relationship between said set point C_c, said torque C_m and said current I_m in order to be able to determine said torque C_m from only said set point C_c and said current I_m.

20. The medium claimed in

claim 19

wherein said initialization unit calculates three coefficients a, b, c of a second order equation relating to set point C_c and said torque C_m and three coefficients a′

, b′

, c′

of a second order equation linking said current I_m and said torque C_m.