A SERIES ACTIVE COMPENSATOR BASED ON SINGLE-PHASE CURRENT SOURCE CONVERTERS IS STUDIED. THE PROPOSAL HAS TWO ADVANTAGES; FIRST, IT REQUIRES JUST A FIRST ORDER CAPACITIVE FILTER ON THE AC SIDE AS COMPARED TO THE SECOND ORDER LC FILTER NEEDED BY VOLTAGE SOURCE BASED TOPOLOGIES. AS A RESULT, SAGS AND SWELLS CAN BE COMPENSATED WITHOUT THE HASSLE OF OSCILLATIONS AT THE LOAD VOLTAGE SIDE; SECOND, AN EXTERNAL CONTROL LOOP IS ADDED TO REGULATE THE DC CURRENT VALUE. THIS TECHNIQUE IS BASED ON THE CONVERTER MODULATING VECTOR MAGNITUDE CONTROL, AND IT GUARANTEES THE SYSTEM OPERATION AT MINIMUM DC LINK CURRENT, WHICH MINIMIZES THE CONDUCTING AND COMMUTATING LOSSES. THE TOPOLOGY AND CONTROL SCHEME CAN BE EXTENDED TO MULTI-LEVEL CONFIGURATIONS, WHICH MAKES THE ARRANGEMENT SUITABLE FOR MEDIUM TO HIGH VOLTAGE APPLICATIONS USING STANDARD SEMICONDUCTORS.

POWER ELECTRONIC LOADS ARE SOURCES OF UNWANTED HARMONIC AS WELL AS REACTIVE POWER. PASSIVE POWER FILTERS AND ACTIVE POWER FILTERS ARE A SUITABLE SOLUTION FOR THOSE POWER QUALITY ISSUES. IF ACTIVE POWER FILTERS ARE USED, THEN IT CONTROLS SYSTEMS NEED TO MEASURE OF HARMONIC AND REACTIVE POWER TO COMPENSATE IT THROUGH A CONTROLLED CURRENT OR VOLTAGE SOURCE. THUS, IT IS IMPORTANT TO DETERMINATE BOTH, FUNDAMENTAL COMPONENT AND HARMONICS COMPONENTS FOR THE ELECTRIC VARIABLE TO BE COMPENSATED. FURTHERMORE, IF THE DESIGN USES A MODULAR APPROACH WITH SEVERAL ACTIVE FILTERS COMPENSATING DIFFERENT HARMONICS THEN THE VALUE OF EACH HARMONIC IN REAL TIME IS REQUIRED. THIS WORK PRESENTS A METHOD TO FIND THE HARMONIC COMPONENTS OF SIGNAL BASED ON A ROBUST PLL WHERE A SINUSOIDAL BASE IS BUILT AND USED TO FIND THE FOURIER COEFFICIENTS FOR THE SELECTED HARMONICS. SIMULATED AND EXPERIMENTAL RESULTS ARE PRESENTED TO VALIDATE THE THEORETICAL CONSIDERATIONS.