Power control of an induction machine
Regulation of the active and reactive power of an induction machine in a coordinate system fixed on the winding, wherein a first regulator output variable is generated using a first regulator as a function of a setpoint variable deviation of the active power and a second regulator output variable is generated using a second regulator as a function of a setpoint variable deviation of the reactive power, feedback variables are added to each of the first and second regulator output variables, which are functions of at least one chronologically changing system variable of the induction machine, and a voltage or a current of the induction machine is determined as a manipulated variable without further regulation at least from the first and second regulator output variables added to the feedback variables. The feedback variables may linearize the regulation path and then allow restriction to only two simple regulators, e.g., two PI regulators. The regulation may be used in double-fed asynchronous machines.
1. A method for regulating active and reactive power of an induction machine in a coordinate system fixed on a winding comprising the steps of:
generating a first regulator output variable using a first regulator as a function of a setpoint value deviation of the active power and a second regulator output variable using a second regulator as a function of a setpoint value deviation of the reactive power, and
adding the first and the second regulator output variables to respective feedback variables, which are functions of at least one time changeable system variable of the induction machine,
wherein a voltage or a current of the induction machine is determined as a manipulated variable at least from the first and second regulator output variables, which have been added to the feedback variables, without an additional subordinate control loop, and
wherein the feedback variables are selected in such a way that the reactive and active powers are at least partially decoupled.
2. The method according to claim 1 , wherein the regulators are linear regulators.
3. The method according to claim 1 , wherein the regulators are PI regulators.
4. The method according to claim 1 , wherein a rotor voltage of the induction machine is determined as the manipulated variable.
5. The method according to claim 1 , wherein a stator voltage of the induction machine is determined as the manipulated variable.
6. The method according to claim 1 , wherein an exciter current of the induction machine is determined as the manipulated variable.
7. The method according to claim 1 , wherein ohmic resistance of a stator of the induction machine is neglected when calculating the feedback variables.
8. The method according to claim 1 , wherein a stationary state is assumed when calculating the feedback variables.
9. The method according to claim 1 , wherein the active and reactive power of the stator of the induction machine is regulated.
10. The method according to claim 1 , wherein active and reactive power of mains ( 3 ) to which the induction machine is connected are regulated.
11. The method according to claim 1 , wherein the first regulator output variable is added to a feedback variable that corresponds to a cross product of rotor voltage and stator flux of the induction machine, and the second regulator output variable is added to a feedback variable that corresponds to a scalar product of rotor voltage and stator flux.
12. The method according to claim 1 , wherein the feedback variables are functions of at least stator voltage, stator flux, rotor current, and rotor speed.
13. The method according to claim 1 , wherein rotor voltage of the induction machine is determined as manipulated variable, without further regulation, from the first and second regulator output variables added to the feedback variables and the stator flux.
14. The method according to claim 1 , wherein at least the stator voltage and the rotor current of the induction machine are measured.
15. The method according to claim 1 , wherein the stator current of the induction machine is measured.
16. The method according to claim 1 , wherein rotor speed of the induction machine is measured or determined from stator voltage, stator current, and rotor current of the induction machine.
17. The method according to claim 1 , wherein rotor position angle of the induction machine is measured or determined from stator voltage, stator current, and rotor current of the induction machine.
18. The method of claim 1 , wherein the stator flux of the induction machine is calculated from the stator and the angular frequency of the stator voltage of the induction machine.
19. The method according to claim 1 , wherein voltages and currents of the induction machine are each measured and then transformed in a two-phase coordinate system, and the manipulated variable is determined in a two-phase coordinate system and then transformed in a three-phase coordinate system.
20. The method according to claim 1 , wherein the induction machine is a double-fed asynchronous machine, whose stator is directly connected to mains, and whose rotor is connected to an inverter.
21. A computer program having commands whose execution causes a processor to perform the method according to claim 1 .
22. A computer program product containing a computer program having commands whose execution causes a processor to perform the method according to claim 1 .
23. A device for regulating active and reactive power of an induction machine in a coordinate system fixed on a winding comprising:
a first regulator for generating a first regulator output variable in the event of setpoint variable deviations of the active power,
a second regulator for generating a second regulator output variable in the event of setpoint variable deviations of the reactive power,
a means for adding each of the first and second regulator output variables to feedback variables, wherein the feedback variables result as functions from at least one time changeable system variable of the induction machine, and
a means, which does not have any further subordinate control loops, for determining a voltage or a current of the induction machine as a manipulated variable from at least the first and second regulator output variables added to the feedback variables,
wherein the active and reactive power can be at least partially decoupled via the means for applying feedback variables to the first and second regulator output variables through the selection of the feedback variables.
24. The device according to claim 23 , wherein the regulators are linear regulators.
25. The device according to claim 23 , wherein the regulators are PI regulators.
26. The device according to claim 23 , wherein the means for determining a voltage or a current of the induction machine determines a rotor voltage as the manipulated variable.
27. The device according to claim 23 , wherein the means for determining a voltage or a current of the induction machine determines a stator voltage as the manipulated variable.
28. The device according to claim 23 , wherein the means for determining a voltage or a current of the induction machine determines an exciter current as the manipulated variable.
29. The device according to claim 23 , wherein the active and reactive power of the stator of the induction machine are regulated.
30. The device according to claim 23 , wherein the active and reactive power of the mains to which the induction machine is connected are regulated.
31. The device according to claim 23 , wherein the regulator output variable of the first regulator is added to a feedback variable that corresponds to a cross product of rotor voltage and stator flux of the induction machine, and the regulator output variable of the second regulator is added to a feedback variable that corresponds to a scalar product of rotor voltage and stator flux.
32. The device according to claim 23 , wherein the feedback variables are functions of at least stator voltage, stator flux, rotor current, and rotor speed.
33. The device according to claim 23 , wherein rotor voltage of the induction machine is determined as the manipulated variables from the first and second regulator output variables added to the feedback variables and stator flux, without further regulation.
34. The device according to claim 23 , wherein the device comprises means for measuring stator voltage and rotor current of the induction machine.
35. The device according to claim 23 , wherein the device comprises means for measuring stator current.
36. The device according to claim 1 , wherein the device comprises means for measuring rotor speed of the induction machine or for determining it from stator voltage, stator current, and rotor current of the induction machine.
37. The device according to claim 23 , wherein the device comprises means for measuring rotor position angle of the induction machine or for determining it from stator voltage, stator current, and rotor current of the induction machine.
38. The device according to claim 34 , wherein the device comprises means for measuring voltages and currents of the induction machine and for transforming them in a two-phase coordinate system, and the device comprises means for transforming the manipulated variable determined in a two-phase coordinate system in a three-phase coordinate system.
39. The device according to claim 23 , wherein the induction machine is a double-fed asynchronous machine, whose stator is connected directly to mains, and whose rotor is connected to an inverter.
40. An induction machine having a device for regulating the active power and reactive power of the induction machine in a coordinate system fixed on the winding according to claim 23 .