Seriesand ShuntCompensators forPower Quality Compensation

Thispaperpresents seriesand shunt compensators basedonneutral point diode clamptopology for powerquality compensation. The function oftheseries compensator istoprevent theloadvoltage variation against the abnormal voltage disturbance, suchasvoltage sagandvoltage swell attheutility side. Thefeature oftheshuntcompensator will supply ordrawactive current fromthesystem tokeepthe dcbusvoltage constant andimprove thecurrent quality atthe utility side. Theneutral point clampinverter hasless voltage stress ofpowersemiconductor comparedwiththevoltage stress ofswitching devices intheconventional full-bridge inverter. Experiments basedona laboratory prototype are presented toverify theeffectiveness andvalidity ofthe proposed control scheme.