초록 ▼

An active filter (300) generates multi-phase compensating current in an AC power supply system (10) that supplies a load (200). The filter (300) includes a compensating current output device (34) outputting multi-phase compensating current to an AC power line (50); and a controller (310) for control

An active filter (300) generates multi-phase compensating current in an AC power supply system (10) that supplies a load (200). The filter (300) includes a compensating current output device (34) outputting multi-phase compensating current to an AC power line (50); and a controller (310) for controlling the compensating current output (340) such that the multi-phase compensating current compensates for current harmonics and power factor on said AC power line (50). The controller (310) estimates current harmonics and power factor compensating values as a function of multi-phase power measurements.

대표청구항 ▼

1. An active filter for generating multi-phase compensating current in an AC power supply system that supplies a load, said filter comprising:a compensating current output device outputting multi-phase compensating current to an AC power line; and a controller for controlling said compensating curre

1. An active filter for generating multi-phase compensating current in an AC power supply system that supplies a load, said filter comprising:a compensating current output device outputting multi-phase compensating current to an AC power line; and a controller for controlling said compensating current output device without using a transformer such that the multi-phase compensating current compensates for current harmonics and power factor on said AC power line, said controller estimating current harmonics and power factor compensating values as a function of multi-phase power measurement. 2. The active filter according to claim 1, wherein said multi-phase compensating current further compensates for phase imbalance of multi-phase voltage and multi-phase current of said power supply system and said controller estimates phase imbalance compensating values as a function of multi-phase supply voltage and multi-phase supply current measurements.3. The active filter according to claim 1, wherein said power supply system is a variable frequency system.4. The active filter according to claim 3, wherein said power system is a variable frequency power system of an aircraft.5. The active filter according to claim 1, wherein the controller estimates the current harmonics and power factor compensating values as a function of a multi-phase voltage measurement.6. An active filter for generating multi-phase compensating current in an AC power supply system that supplies a load, said filter comprising:a compensating current output device outputting multi-phase compensating current to an AC power line; and a controller for controlling said compensating current output such that the multi-phase compensating current compensates for current harmonics and power factor on said AC power line, said controller estimating current harmonics and power factor compensating values as a function of multi-phase power measurement, wherein said controller comprises: a digital phase lock loop unit that computes voltage reference signals in a quadratic domain. 7. The active filter according to claim 6, wherein said controller further comprises:a compensating current reference estimator that estimates compensating current reference values based on voltage reference signals computed by said digital phase lock loop unit, said compensating current reference values being in the quadratic domain; and a domain transformer for transforming said compensating current reference values from said quadratic domain to a multi-phase current domain by using a look-up table. 8. The active filter according to claim 7, whereinsaid compensating current output is an inverter, and said controller further comprises: an inverter switching control unit that generates inverter switching control signals in accordance with calculated compensating current values. 9. The active filter according to claim 6, wherein said digital phase lock loop unit calculates reference voltage values by:transforming multi-phase voltage measurement values into a quadratic (d-q) reference frame signals; filtering the quadratic (d-q) reference frame signals to extract fundamental d-q voltage signals; and processing the fundamental d-q voltage signals to generate said reference voltage values. 10. The active filter according to claim 7, wherein said compensating current reference estimator transforms multi-phase current measurements into transformed current values, said transformed current values having a DC component corresponding to a fundamental current, an AC component corresponding to current harmonics, and a zero sequence current corresponding to multi-phase current balance.11. The active filter according to claim 7, wherein said compensating current reference values represent a plurality of power conditions, including current harmonics, power factor, and multi-phase current balance.12. The active filter according to claim 7, wherein said compensating current reference estimator accesses a look up table to generate said compensating current reference values and to achieve desired power quality combinations.13. A controller of an active filter that generates multi-phase compensating current in an AC power supply system that supplies a load, said controller comprising:an input for receiving multi-phase power measurements; a compensating current calculation unit for calculating multi-phase compensating current based on said multi-phase power measurements; and an output for outputting control signals based on the calculated multi-phase compensating current to control a compensating current output device to compensate for current harmonics and power factor on an AC power line without using a transformer. 14. The controller according to claim 13, wherein said multi-phase compensating current further compensates for phase imbalance of multi-phase voltage and multi-phase current of said power supply system and said controller estimates phase imbalance compensating values as a function of multi-phase supply voltage and multi-phase supply current measurements.15. The controller according to claim 13, wherein said power supply system is a variable frequency system.16. The controller according to claim 15, wherein said power system is a variable frequency power system of an aircraft.17. The controller according to claim 13, wherein the compensating current calculation unit calculates the multi-phase compensating current based on a multi-phase voltage measurement.18. A controller of an active filter that generates multi-phase compensating current in an AC power supply system that supplies a load, said controller comprising:an input for receiving multi-phase power measurements; a compensating current calculation unit for calculating multi-phase compensating current based on said multi-phase power measurements; and an output for outputting control signals based on the calculated multi-phase compensating current to control a compensating current output device to compensate for current harmonics and power factor on an AC power line, wherein said compensating current calculation unit comprises: a digital phase lock loop unit that computes voltage reference signals in a quadratic domain. 19. The controller according to claim 18, wherein said compensating current calculation unit further comprises:a compensating current reference estimator that estimates compensating current reference values based on voltage reference signals computed by said digital phase lock loop unit, said compensating current reference values being in the quadratic domain; and a domain transformer for transforming said compensating current reference values from said quadratic domain to a multi-phase current domain by using a look-up table. 20. The controller according to claim 19, whereinsaid compensating current output is an inverter, and said controller generates inverter switching control signals in accordance with calculated compensating current values. 21. The controller according to claim 19, wherein said digital phase lock loop unit calculates reference voltage values by:transforming multi-phase voltage measurement values into a quadratic (d-q) reference frame signals; filtering the quadratic (d-q) reference frame signals to extract fundamental d-q voltage signals; and processing the fundamental d-q voltage signals to generate said reference voltage values. 22. The controller according to claim 19, wherein said compensating current reference estimator transforms multi-phase current measurements into transformed current values, said transformed current values having a DC component corresponding to a fundamental current, an AC component corresponding to current harmonics, and a zero sequence current corresponding to multi-phase current balance.23. The controller according to claim 19, wherein said compensating current reference values represent a plurality of power conditions, including current harmonics, power factor, and multi-phase current balance.24. The controller according to claim 19, wherein said compensating current reference estimator accesses a look up table to generate said compensating current reference values and to achieve desired power quality combinations.25. A method of generating multi-phase compensating current in an AC power supply system that supplies a load, said method comprising:outputting multi-phase compensating current to an AC power line without using a transformer; and adjusting the compensating current output to the AC power line without using a transformer such that the multi-phase compensating current compensates for current harmonics and power factor on the AC power line, said adjusting step estimating current harmonics and power factor compensating values as a function of multi-phase power measurement. 26. The method according to claim 25, wherein said multi-phase compensating current further compensates for phase imbalance of multi-phase voltage and multi-phase current of the power supply system and said step of adjusting estimates phase imbalance compensating values as a function of multi-phase supply voltage and multi-phase supply current measurements.27. The method according to claim 25, wherein said power supply system is a variable frequency system.28. The method according to claim 27, wherein said power system is a variable frequency power system of an aircraft.29. The method according to claim 25, wherein the current harmonics and power factor compensating values are estimated as a function of a multi-phase voltage measurement.30. The method of generating multi-phase compensating current in an AC power supply system that supplies a load, said method comprising:outputting multi-phase compensating current to an AC power line; and adjusting the compensating current output to the AC power line such that the multi-phase compensating current compensates for current harmonics and power factor on the AC power line, said adjusting step estimating current harmonics and power factor compensating values as a function of multi-phase power measurement, wherein said step of adjusting comprises: executing a digital phase lock loop function that computes voltage reference signals in a quadratic domain. 31. The method according to claim 30, wherein said step of adjusting further comprises:estimating compensating current reference values based on voltage reference signals computed by said digital phase lock loop function, said compensating current reference values being in the quadratic domain; and transforming said compensating current reference values from said quadratic domain to a multi-phase current domain by using a look-up table. 32. The method according to claim 30 wherein said digital phase lock loop function calculates reference voltage values by:transforming multi-phase voltage measurement values into a quadratic (d-q) reference frame signals; filtering the quadratic (d-q) reference frame signals to extract fundamental d-q voltage signals; and processing the fundamental d-q voltage signals to generate said reference voltage values. 33. The method according to claim 31, wherein said compensating current reference values represent a plurality of power conditions, including current harmonics, power factor, and multi-phase current balance.34. The method according to claim 31, wherein said step of estimating compensating current reference values accesses a look up table to generate said compensating current reference values and to achieve desired power quality combinations.