Voltage fluctuation and higher harmonics suppressor
First Claim
1. A device for suppressing voltage fluctuation and higher harmonics of a power system which supplies power to a load with large power fluctuation and higher harmonic current, said device comprising:
- a self-commutated converter provided in parallel with said load;
a higher harmonic filter provided in parallel with said load;
first calculation means connected to receive a load current flowing through said load and a system voltage of said power system for calculating a reactive power consumed by said load based on said load current and said system voltage and for generating a fundamental harmonic current command value to compensate said reactive power;
second calculation means connected to receive a current flowing from said power system for detecting a higher harmonic current flowing out to said power system and for generating a higher harmonic current command value to suppress said higher harmonic current;
adder means connected to said first and second calculation means for adding said fundamental harmonic current command value and said higher harmonic current command value to generate a current command value of said self-commutated convertion; and
control means connected to receive said current command value for controlling said self-commutate converter based on said current command value;
thereby suppressing said voltage fluctuation and higher harmonics of said power system.
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Abstract
A device for suppressing voltage fluctuation and higher harmonics of a power system which supplies power to a load with large power fluctuation and higher harmonic current. The device includes a self-commutated converter and a higher harmonic filter, both provided in parallel with the load. The device includes a first calculation circuit which calculates a reactive power consumed by the load based on a load current and system voltage and generates a fundamental harmonic current command value to compensate the reactive power. The device further includes a second calculation circuit which detects a higher harmonic current flowing out to the power system based on a current flowing from the power system and generates a higher harmonic current command value to suppress the higher harmonic current. The device further includes an adder which adds the fundamental harmonic current command value and the higher harmonic current command value to generate a current command value of the self-commutated converter. The device includes a control circuit which receive the current command value for controlling the self-commutated converter.
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Citations
5 Claims
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1. A device for suppressing voltage fluctuation and higher harmonics of a power system which supplies power to a load with large power fluctuation and higher harmonic current, said device comprising:
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a self-commutated converter provided in parallel with said load; a higher harmonic filter provided in parallel with said load; first calculation means connected to receive a load current flowing through said load and a system voltage of said power system for calculating a reactive power consumed by said load based on said load current and said system voltage and for generating a fundamental harmonic current command value to compensate said reactive power; second calculation means connected to receive a current flowing from said power system for detecting a higher harmonic current flowing out to said power system and for generating a higher harmonic current command value to suppress said higher harmonic current; adder means connected to said first and second calculation means for adding said fundamental harmonic current command value and said higher harmonic current command value to generate a current command value of said self-commutated convertion; and control means connected to receive said current command value for controlling said self-commutate converter based on said current command value; thereby suppressing said voltage fluctuation and higher harmonics of said power system. - View Dependent Claims (2, 3, 4, 5)
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Specification