Method of controlling electric motors, corresponding device and motor

Patent metadata

Field	Value
Publication number	US-10476414-B2
Application number	US-201615377911-A
Country	US
Kind code	B2
Filing date	Dec 13, 2016
Priority date	Jun 28, 2016
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

A driving circuit for an electric motor including multiple windings includes a sensing circuit to sense motor winding currents. A motor rotation angle signal is generated from the sensed currents and motor control voltages are generated as a function of the motor rotation angle signal. The motor windings are driven with motor drive voltages obtained by injecting into the motor control voltages injection pulses. The sensed currents include both torque components and injection components. The motor rotation angle signal is generated as a function of the injection components of the sensed currents.

First claim

The invention claimed is:

1. A method of driving an electric motor including a plurality of windings, the method including:
sensing currents in the motor windings,
generating a motor rotation angle signal from the sensed currents,
generating motor control voltages as a function of said motor rotation angle signal,
simultaneously superimposing a pair of injection pulses on a corresponding pair of said motor control voltages to generate first and second motor drive voltages, without simultaneously superimposing an injection pulse on any other motor control voltage to generate a third motor drive voltage, wherein the pair of injection pulses comprises a first pulse and a second pulse and the first and second pulses have a 180 degree phase difference with respect to each other, and
applying the generated first, second and third motor drive voltages directly to corresponding windings of said plurality of windings of said electric motor,
wherein said sensed currents include torque components and injection components, and
wherein generating said motor rotation angle signal comprises generating the motor rotation angle signal as a function of said injection components of the sensed currents.

2. The method of claim 1 , wherein sensing currents comprises sensing said currents by subtraction between periods with opposed injected voltage polarity.

3. The method of claim 1 , wherein the motor includes three windings energized in three phases, respectively, the method including simultaneously superimposing said pair of injection pulses in two of said three phases without simultaneously superimposing any injection pulse in the third of said three phases, and wherein the sensed current is in the winding for the third of said three phases.

4. The method of claim 1 , wherein the motor has an impedance having resistive and inductive components R and L, respectively, the method including starting simultaneously superimposing said pair of injection pulses at an angle υ=arctg(L/R).

5. The method of claim 1 , wherein said pair of injection pulses include sinusoidal injection pulses.

6. The method of claim 1 , wherein said pair of injection pulses include square wave injection pulses.

7. The method of claim 1 , including:
generating from said motor rotation angle signal a motor rotation speed signal, and
generating said motor control voltages as a function of both said motor rotation angle signal and said motor rotation speed signal.

8. A device for driving an electric motor including a plurality of windings, the device including:
a sensing module configured to sense currents in the motor windings, and
a driving system configured to:
generate a motor rotation angle signal from the sensed currents,
generate motor control voltages as a function of said motor rotation angle signal,
simultaneously superimpose a pair of injection pulses on a corresponding pair of said motor control voltages to generate first and second motor drive voltages, without simultaneously superimposing an injection pulse on any other motor control voltage to generate a third motor drive voltage, wherein the pair of injection pulses comprises a first pulse and a second pulse and the first and second pulses have a 180 degree phase difference with respect to each other,
apply the generated first, second and third motor drive voltages directly to corresponding windings of said plurality of windings of said electric motor,
wherein said sensed currents include torque components and injection components, and
generate said motor rotation angle signal as a function of said injection components of the sensed currents.

9. The device of claim 8 , wherein the sensing module is configured to sense currents by subtraction between periods with opposed injected voltage polarity.

10. The device of claim 8 , wherein the motor includes three windings energized in three phases, respectively, said driving system configured to simultaneously superimpose said pair of injection pulses in two of said three phases without simultaneously superimposing any injection pulse in the third of said three phases, and wherein the sensed current is in the winding for the third of said three phases.

11. The device of claim 8 , wherein the motor has an impedance having resistive and inductive components R and L, respectively, said driving system configured to start simultaneously superimposing said pair of injection pulses at an angle υ=arctg(L/R).

12. The device of claim 8 , wherein said pair of injection pulses include sinusoidal injection pulses.

13. The device of claim 8 , wherein said par of injection pulses include square wave injection pulses.

14. The device of claim 8 , where said driving system is further configured to:
generate from said motor rotation angle signal a motor rotation speed signal, and
generate said motor control voltages as a function of both said motor rotation angle signal and said motor rotation speed signal.

15. A method of driving an electric motor including a first winding, a second winding and a third winding, the method including:
sensing currents in the first, second and third windings,
generating a motor rotation angle signal from the sensed currents,
generating first, second and third motor control voltages as a function of said motor rotation angle signal,
simultaneously performing:
injecting into the first motor control voltage a first injection pulse to generate a first motor drive voltage that is directly applied to the first winding,
injecting into the second motor control voltage a second injection pulse to generate a second motor drive voltage that is directly applied to the second winding, and
not injecting any injection pulse into the third motor control voltage to generate a third motor drive voltage that is directly applied to the third winding,

wherein the first and second injection pulses have a 180 degree phase difference with respect to each other, and
wherein generating said motor rotation angle signal comprises generating the motor rotation angle signal as a function of injection components within the sensed currents that result from the first and second injection pulses.

16. The method of claim 15 , wherein the motor has an impedance having resistive and inductive components R and L, respectively, the method including starting injecting the first and second injection pulses at an angle υ=arctg(L/R).

17. The method of claim 15 , wherein said first and second injection pulses are sinusoidal pulses.

18. The method of claim 15 , wherein said first and second injection pulses are square wave pulses.

19. The method of claim 15 , including:
generating a motor rotation speed signal from said motor rotation angle signal, and
generating said motor control voltages as a function of both said motor rotation angle signal and said motor rotation speed signal.

20. A method of driving an electric motor including first, second and third windings, the method including:
generating first, second and third motor control voltages;
simultaneously superimposing a first injection pulse and a second injection pulse on the first and second motor control voltages, without simultaneously superimposing an injection pulse on the third motor control voltage, to generate corresponding first, second and third motor drive voltages for application to the first, second and third windings, respectively, of the electric motor;
wherein the first injection pulse and the second injection pulse have a 180 degree phase difference with respect to each other;

Assignees

• St Microelectronics Des & Appl
• St Microelectronics Srl

Inventors

• Ryba Jiri
• Forte Gianluigi
• Spampinato Andrea

Classifications

• H02P6/18 Primary

  without separate position detecting elements · CPC title

• H02P6/183 Primary

  using an injected high frequency signal · CPC title